diff mbox series

[v13,2/3] i2c: aspeed: support AST2600 i2c new register mode driver

Message ID 20240819092850.1590758-3-ryan_chen@aspeedtech.com
State New
Headers show
Series Add ASPEED AST2600 I2Cv2 controller driver | expand

Commit Message

Ryan Chen Aug. 19, 2024, 9:28 a.m. UTC
Add i2c new register mode driver to support AST2600 i2c
new register mode. AST2600 i2c controller have legacy and
new register mode. The new register mode have global register
support 4 base clock for scl clock selection, and new clock
divider mode. The new register mode have separate register
set to control i2c master and slave. This patch is for i2c
master mode driver.

Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
---
 drivers/i2c/busses/Kconfig       |   11 +
 drivers/i2c/busses/Makefile      |    1 +
 drivers/i2c/busses/i2c-ast2600.c | 1057 ++++++++++++++++++++++++++++++
 3 files changed, 1069 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-ast2600.c

Comments

Ryan Chen Aug. 23, 2024, 6:23 a.m. UTC | #1
> Subject: Re: [PATCH v13 2/3] i2c: aspeed: support AST2600 i2c new register
> mode driver
> 
> On Thu, Aug 22, 2024 at 02:24:26AM +0000, Ryan Chen wrote:
> > > On Wed, Aug 21, 2024 at 06:43:01AM +0000, Ryan Chen wrote:
> > > > > On Mon, Aug 19, 2024 at 05:28:49PM +0800, Ryan Chen wrote:
> 
> ...
> 
> > > > > > +	/* Check 0x14's SDA and SCL status */
> > > > > > +	state = readl(i2c_bus->reg_base +
> AST2600_I2CC_STS_AND_BUFF);
> > > > > > +	if (!(state & AST2600_I2CC_SDA_LINE_STS) && (state &
> > > > > AST2600_I2CC_SCL_LINE_STS)) {
> > > > > > +		writel(AST2600_I2CM_RECOVER_CMD_EN,
> i2c_bus->reg_base
> > > +
> > > > > AST2600_I2CM_CMD_STS);
> > > > > > +		r =
> wait_for_completion_timeout(&i2c_bus->cmd_complete,
> > > > > i2c_bus->adap.timeout);
> > > > > > +		if (r == 0) {
> > > > > > +			dev_dbg(i2c_bus->dev, "recovery timed out\n");
> > > > > > +			ret = -ETIMEDOUT;
> > > > > > +		} else {
> > > > > > +			if (i2c_bus->cmd_err) {
> > > > > > +				dev_dbg(i2c_bus->dev, "recovery error\n");
> > > > > > +				ret = -EPROTO;
> > > > > > +			}
> > > > > > +		}
> > > > > > +	}
> > > > >
> > > > > ret is set but maybe overridden.
> > > >
> > > > If will modify by following.
> > > > 		if (r == 0) {
> > > > 			dev_dbg(i2c_bus->dev, "recovery timed out\n");
> > > > 			ret = -ETIMEDOUT;
> > > > 		} else if (i2c_bus->cmd_err) {
> > > > 			dev_dbg(i2c_bus->dev, "recovery error\n");
> > > > 			ret = -EPROTO;
> > > > 		}
> > > > If no error keep ret = 0;
> > >
> > > It doesn't change the behaviour. Still ret can be overridden below...
> >
> > Yes, it is expectable, previous is issue recovery command out then the
> > following is double confirm the bus status.
> > If bus still busy, the function still return recovery fail.
> >
> > Or should I modify by following?
> > 	/* Check 0x14's SDA and SCL status */
> > 	state = readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
> > 	if (!(state & AST2600_I2CC_SDA_LINE_STS) && (state &
> AST2600_I2CC_SCL_LINE_STS)) {
> > 		writel(AST2600_I2CM_RECOVER_CMD_EN, i2c_bus->reg_base +
> AST2600_I2CM_CMD_STS);
> > 		r = wait_for_completion_timeout(&i2c_bus->cmd_complete,
> i2c_bus->adap.timeout);
> > 		if (r == 0) {
> > 			dev_dbg(i2c_bus->dev, "recovery timed out\n");
> 
> > 			ret = -ETIMEDOUT;
> 
> This assignment doesn't make sense.

> 
> > 		} else if (i2c_bus->cmd_err) {
> > 				dev_dbg(i2c_bus->dev, "recovery error\n");
> > 				ret = -EPROTO;
> > 		}
> > 		/* check bus status */
> > 		state = readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
> > 		if (state & AST2600_I2CC_BUS_BUSY_STS) {
> > 			dev_dbg(i2c_bus->dev, "Can't recover bus [%x]\n", state);
> > 			ret = -EPROTO;
> > 		}
> > 	}
> 
> > > > > > +	/* Recovery done */
> > > > >
> > > > > Even if it fails above?
> > > >
> > > > This will keep check the bus status, if bus busy, will give ret =
> > > > -EPROTO;
> > > >
> > > > > > +	state = readl(i2c_bus->reg_base +
> AST2600_I2CC_STS_AND_BUFF);
> > > > > > +	if (state & AST2600_I2CC_BUS_BUSY_STS) {
> > > > > > +		dev_dbg(i2c_bus->dev, "Can't recover bus [%x]\n", state);
> > > > > > +		ret = -EPROTO;
> > >
> > > ...here.
> 
> See above.
OH, I understand now.
I will modify following

	if (!(state & AST2600_I2CC_SDA_LINE_STS) && (state & AST2600_I2CC_SCL_LINE_STS)) {
		writel(AST2600_I2CM_RECOVER_CMD_EN, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
		r = wait_for_completion_timeout(&i2c_bus->cmd_complete, i2c_bus->adap.timeout);
		if (r == 0) {
			dev_dbg(i2c_bus->dev, "recovery timed out\n");
++			writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
++			return -ETIMEDOUT;
		} else {
			if (i2c_bus->cmd_err) {
				dev_dbg(i2c_bus->dev, "recovery error\n");
				ret = -EPROTO;
			}
		}

> > > > > > +	}
> > > > > > +
> > > > > > +	/* restore original master/slave setting */
> > > > > > +	writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > > > > > +	return ret;
> 
> ...
> 
> > > > > > +		i2c_bus->master_dma_addr =
> > > > > > +			dma_map_single(i2c_bus->dev,
> i2c_bus->master_safe_buf,
> > > > > > +				       msg->len, DMA_TO_DEVICE);
> > > > >
> > > > > > +		if (dma_mapping_error(i2c_bus->dev,
> > > i2c_bus->master_dma_addr))
> > > > > {
> > > > > > +
> 	i2c_put_dma_safe_msg_buf(i2c_bus->master_safe_buf,
> > > msg,
> > > > > false);
> > > > > > +			i2c_bus->master_safe_buf = NULL;
> > > > >
> > > > > > +			return -ENOMEM;
> > > > >
> > > > > Why is the dma_mapping_error() returned error code shadowed?
> > > >
> > > > Sorry, please point me why you are think it is shadowed?
> > > > As I know dma_mapping_error() will return 0 or -ENOMEM. So I check
> > > > if it
> > > is !=0.
> > > > Than return -ENOMEM.
> > >
> > > First of all, it is a bad style to rely on the implementation
> > > details where it's not crucial. Second, today it may return only
> > > ENOMEM, tomorrow it can return a different code or codes. And in
> > > general, one should not shadow an error code without justification.
> > >
> > Understood, The following is better, am I right? (if yest, those will
> > update in driver)
> 
> Yes.
Thanks.
> 
> > 		Int ret;
> > 		.....
> > 		ret = dma_mapping_error(i2c_bus->dev,
> i2c_bus->master_dma_addr)
> > 		if (ret) {
> > 			i2c_put_dma_safe_msg_buf(i2c_bus->master_safe_buf, msg,
> false);
> > 			i2c_bus->master_safe_buf = NULL;
> > 			return ret;
> > 		}
> >
> > > > > > +		}
> 
> ...
> 
> > > > > > +	if (i2c_bus->mode == BUFF_MODE) {
> > > > > > +		i2c_bus->buf_base =
> > > > > devm_platform_get_and_ioremap_resource(pdev, 1, &res);
> > > > > > +		if (!IS_ERR_OR_NULL(i2c_bus->buf_base))
> > > > > > +			i2c_bus->buf_size = resource_size(res) / 2;
> > > > > > +		else
> > > > > > +			i2c_bus->mode = BYTE_MODE;
> > > > >
> > > > > What's wrong with positive conditional? And is it even possible
> > > > > to have NULL here?
> > > > >
> > > > Yes, if dtsi fill not following yaml example have reg 1, that will
> > > > failure at buffer
> > > mode.
> > > > And I can swith to byte mode.
> > > >
> > > > reg = <0x80 0x80>, <0xc00 0x20>;
> > >
> > > I was asking about if (!IS_ERR_OR_NULL(...)) line:
> > > 1) Why 'if (!foo) {} else {}' instead of 'if (foo) {} else {}'?
> > I will update to following.
> > 		if (IS_ERR(i2c_bus->buf_base))
> > 			i2c_bus->mode = BYTE_MODE;
> > 		else
> > 			i2c_bus->buf_size = resource_size(res) / 2;
> >
> > > 2) Why _NULL?
> > 	If dtsi file is claim only 1 reg offset. reg = <0x80 0x80>; that will goto byte
> mode.
> > 	reg = <0x80 0x80>, <0xc00 0x20>; can support buffer mode.
> > 	due to 2nd is buffer register offset.
> 
> I have asked why IS_ERR_OR_NULL() and not IS_ERR().
> 
OH, I will doing by this.
		if (IS_ERR_OR_NULL(i2c_bus->buf_base))
			i2c_bus->mode = BYTE_MODE;
		else
			i2c_bus->buf_size = resource_size(res) / 2;

> 
> --
> With Best Regards,
> Andy Shevchenko
>
Andy Shevchenko Aug. 23, 2024, 2:03 p.m. UTC | #2
On Fri, Aug 23, 2024 at 06:23:54AM +0000, Ryan Chen wrote:
> > On Thu, Aug 22, 2024 at 02:24:26AM +0000, Ryan Chen wrote:
> > > > On Wed, Aug 21, 2024 at 06:43:01AM +0000, Ryan Chen wrote:
> > > > > > On Mon, Aug 19, 2024 at 05:28:49PM +0800, Ryan Chen wrote:

...

> > > > > > > +	if (i2c_bus->mode == BUFF_MODE) {
> > > > > > > +		i2c_bus->buf_base =
> > > > > > devm_platform_get_and_ioremap_resource(pdev, 1, &res);
> > > > > > > +		if (!IS_ERR_OR_NULL(i2c_bus->buf_base))
> > > > > > > +			i2c_bus->buf_size = resource_size(res) / 2;
> > > > > > > +		else
> > > > > > > +			i2c_bus->mode = BYTE_MODE;
> > > > > >
> > > > > > What's wrong with positive conditional? And is it even possible
> > > > > > to have NULL here?
> > > > > >
> > > > > Yes, if dtsi fill not following yaml example have reg 1, that will
> > > > > failure at buffer
> > > > mode.
> > > > > And I can swith to byte mode.
> > > > >
> > > > > reg = <0x80 0x80>, <0xc00 0x20>;
> > > >
> > > > I was asking about if (!IS_ERR_OR_NULL(...)) line:
> > > > 1) Why 'if (!foo) {} else {}' instead of 'if (foo) {} else {}'?
> > > I will update to following.
> > > 		if (IS_ERR(i2c_bus->buf_base))
> > > 			i2c_bus->mode = BYTE_MODE;
> > > 		else
> > > 			i2c_bus->buf_size = resource_size(res) / 2;
> > >
> > > > 2) Why _NULL?
> > > 	If dtsi file is claim only 1 reg offset. reg = <0x80 0x80>; that will goto byte
> > mode.
> > > 	reg = <0x80 0x80>, <0xc00 0x20>; can support buffer mode.
> > > 	due to 2nd is buffer register offset.
> > 
> > I have asked why IS_ERR_OR_NULL() and not IS_ERR().
> > 
> OH, I will doing by this.
> 		if (IS_ERR_OR_NULL(i2c_bus->buf_base))

The question about _NULL remains unanswered...

> 			i2c_bus->mode = BYTE_MODE;
> 		else
> 			i2c_bus->buf_size = resource_size(res) / 2;
Ryan Chen Aug. 26, 2024, 7:50 a.m. UTC | #3
> Subject: Re: [PATCH v13 2/3] i2c: aspeed: support AST2600 i2c new register
> mode driver
> 
> On Fri, Aug 23, 2024 at 06:23:54AM +0000, Ryan Chen wrote:
> > > On Thu, Aug 22, 2024 at 02:24:26AM +0000, Ryan Chen wrote:
> > > > > On Wed, Aug 21, 2024 at 06:43:01AM +0000, Ryan Chen wrote:
> > > > > > > On Mon, Aug 19, 2024 at 05:28:49PM +0800, Ryan Chen wrote:
> 
> ...
> 
> > > > > > > > +	if (i2c_bus->mode == BUFF_MODE) {
> > > > > > > > +		i2c_bus->buf_base =
> > > > > > > devm_platform_get_and_ioremap_resource(pdev, 1, &res);
> > > > > > > > +		if (!IS_ERR_OR_NULL(i2c_bus->buf_base))
> > > > > > > > +			i2c_bus->buf_size = resource_size(res) / 2;
> > > > > > > > +		else
> > > > > > > > +			i2c_bus->mode = BYTE_MODE;
> > > > > > >
> > > > > > > What's wrong with positive conditional? And is it even
> > > > > > > possible to have NULL here?
> > > > > > >
> > > > > > Yes, if dtsi fill not following yaml example have reg 1, that
> > > > > > will failure at buffer
> > > > > mode.
> > > > > > And I can swith to byte mode.
> > > > > >
> > > > > > reg = <0x80 0x80>, <0xc00 0x20>;
> > > > >
> > > > > I was asking about if (!IS_ERR_OR_NULL(...)) line:
> > > > > 1) Why 'if (!foo) {} else {}' instead of 'if (foo) {} else {}'?
> > > > I will update to following.
> > > > 		if (IS_ERR(i2c_bus->buf_base))
> > > > 			i2c_bus->mode = BYTE_MODE;
> > > > 		else
> > > > 			i2c_bus->buf_size = resource_size(res) / 2;
> > > >
> > > > > 2) Why _NULL?
> > > > 	If dtsi file is claim only 1 reg offset. reg = <0x80 0x80>; that
> > > > will goto byte
> > > mode.
> > > > 	reg = <0x80 0x80>, <0xc00 0x20>; can support buffer mode.
> > > > 	due to 2nd is buffer register offset.
> > >
> > > I have asked why IS_ERR_OR_NULL() and not IS_ERR().
> > >
> > OH, I will doing by this.
> > 		if (IS_ERR_OR_NULL(i2c_bus->buf_base))
> 
> The question about _NULL remains unanswered...
Sorry, I may not catch your point.
So, Do you mean I should passive coding by following?

If (i2c_bus->buf_base > 0)
	i2c_bus->buf_size = resource_size(res) / 2;
else
    i2c_bus->mode = BYTE_MODE;

> 
> > 			i2c_bus->mode = BYTE_MODE;
> > 		else
> > 			i2c_bus->buf_size = resource_size(res) / 2;
> 
> --
> With Best Regards,
> Andy Shevchenko
>
Andy Shevchenko Aug. 26, 2024, 10:38 a.m. UTC | #4
On Mon, Aug 26, 2024 at 07:50:24AM +0000, Ryan Chen wrote:
> > On Fri, Aug 23, 2024 at 06:23:54AM +0000, Ryan Chen wrote:
> > > > On Thu, Aug 22, 2024 at 02:24:26AM +0000, Ryan Chen wrote:
> > > > > > On Wed, Aug 21, 2024 at 06:43:01AM +0000, Ryan Chen wrote:
> > > > > > > > On Mon, Aug 19, 2024 at 05:28:49PM +0800, Ryan Chen wrote:

...

> > > > > > > > > +	if (i2c_bus->mode == BUFF_MODE) {
> > > > > > > > > +		i2c_bus->buf_base =
> > > > > > > > devm_platform_get_and_ioremap_resource(pdev, 1, &res);
> > > > > > > > > +		if (!IS_ERR_OR_NULL(i2c_bus->buf_base))
> > > > > > > > > +			i2c_bus->buf_size = resource_size(res) / 2;
> > > > > > > > > +		else
> > > > > > > > > +			i2c_bus->mode = BYTE_MODE;
> > > > > > > >
> > > > > > > > What's wrong with positive conditional? And is it even
> > > > > > > > possible to have NULL here?
> > > > > > > >
> > > > > > > Yes, if dtsi fill not following yaml example have reg 1, that
> > > > > > > will failure at buffer
> > > > > > mode.
> > > > > > > And I can swith to byte mode.
> > > > > > >
> > > > > > > reg = <0x80 0x80>, <0xc00 0x20>;
> > > > > >
> > > > > > I was asking about if (!IS_ERR_OR_NULL(...)) line:
> > > > > > 1) Why 'if (!foo) {} else {}' instead of 'if (foo) {} else {}'?
> > > > > I will update to following.
> > > > > 		if (IS_ERR(i2c_bus->buf_base))
> > > > > 			i2c_bus->mode = BYTE_MODE;
> > > > > 		else
> > > > > 			i2c_bus->buf_size = resource_size(res) / 2;
> > > > >
> > > > > > 2) Why _NULL?
> > > > > 	If dtsi file is claim only 1 reg offset. reg = <0x80 0x80>; that
> > > > > will goto byte
> > > > mode.
> > > > > 	reg = <0x80 0x80>, <0xc00 0x20>; can support buffer mode.
> > > > > 	due to 2nd is buffer register offset.
> > > >
> > > > I have asked why IS_ERR_OR_NULL() and not IS_ERR().
> > > >
> > > OH, I will doing by this.
> > > 		if (IS_ERR_OR_NULL(i2c_bus->buf_base))
> > 
> > The question about _NULL remains unanswered...
> Sorry, I may not catch your point.
> So, Do you mean I should passive coding by following?

No. I already mentioned that in one of the previous mails.
Why do you use IS_ERR_OR_NULL() and not IS_ERR()?

You should understand your code better than me :-)

> If (i2c_bus->buf_base > 0)
> 	i2c_bus->buf_size = resource_size(res) / 2;
> else
>     i2c_bus->mode = BYTE_MODE;
> 
> > > 			i2c_bus->mode = BYTE_MODE;
> > > 		else
> > > 			i2c_bus->buf_size = resource_size(res) / 2;
Ryan Chen Aug. 28, 2024, 2:34 a.m. UTC | #5
> Subject: Re: [PATCH v13 2/3] i2c: aspeed: support AST2600 i2c new register
> mode driver
> 
> On Mon, Aug 26, 2024 at 07:50:24AM +0000, Ryan Chen wrote:
> > > On Fri, Aug 23, 2024 at 06:23:54AM +0000, Ryan Chen wrote:
> > > > > On Thu, Aug 22, 2024 at 02:24:26AM +0000, Ryan Chen wrote:
> > > > > > > On Wed, Aug 21, 2024 at 06:43:01AM +0000, Ryan Chen wrote:
> > > > > > > > > On Mon, Aug 19, 2024 at 05:28:49PM +0800, Ryan Chen wrote:
> 
> ...
> 
> > > > > > > > > > +	if (i2c_bus->mode == BUFF_MODE) {
> > > > > > > > > > +		i2c_bus->buf_base =
> > > > > > > > > devm_platform_get_and_ioremap_resource(pdev, 1, &res);
> > > > > > > > > > +		if (!IS_ERR_OR_NULL(i2c_bus->buf_base))
> > > > > > > > > > +			i2c_bus->buf_size = resource_size(res) / 2;
> > > > > > > > > > +		else
> > > > > > > > > > +			i2c_bus->mode = BYTE_MODE;
> > > > > > > > >
> > > > > > > > > What's wrong with positive conditional? And is it even
> > > > > > > > > possible to have NULL here?
> > > > > > > > >
> > > > > > > > Yes, if dtsi fill not following yaml example have reg 1,
> > > > > > > > that will failure at buffer
> > > > > > > mode.
> > > > > > > > And I can swith to byte mode.
> > > > > > > >
> > > > > > > > reg = <0x80 0x80>, <0xc00 0x20>;
> > > > > > >
> > > > > > > I was asking about if (!IS_ERR_OR_NULL(...)) line:
> > > > > > > 1) Why 'if (!foo) {} else {}' instead of 'if (foo) {} else {}'?
> > > > > > I will update to following.
> > > > > > 		if (IS_ERR(i2c_bus->buf_base))
> > > > > > 			i2c_bus->mode = BYTE_MODE;
> > > > > > 		else
> > > > > > 			i2c_bus->buf_size = resource_size(res) / 2;
> > > > > >
> > > > > > > 2) Why _NULL?
> > > > > > 	If dtsi file is claim only 1 reg offset. reg = <0x80 0x80>;
> > > > > > that will goto byte
> > > > > mode.
> > > > > > 	reg = <0x80 0x80>, <0xc00 0x20>; can support buffer mode.
> > > > > > 	due to 2nd is buffer register offset.
> > > > >
> > > > > I have asked why IS_ERR_OR_NULL() and not IS_ERR().
> > > > >
> > > > OH, I will doing by this.
> > > > 		if (IS_ERR_OR_NULL(i2c_bus->buf_base))
> > >
> > > The question about _NULL remains unanswered...
> > Sorry, I may not catch your point.
> > So, Do you mean I should passive coding by following?
> 
> No. I already mentioned that in one of the previous mails.
> Why do you use IS_ERR_OR_NULL() and not IS_ERR()?
> 
> You should understand your code better than me :-)
Understood, I will change to 
	if (IS_ERR(i2c_bus->buf_base))
		i2c_bus->mode = BYTE_MODE;
	else
		i2c_bus->buf_size = resource_size(res) / 2;

> > If (i2c_bus->buf_base > 0)
> > 	i2c_bus->buf_size = resource_size(res) / 2; else
> >     i2c_bus->mode = BYTE_MODE;
> >
> > > > 			i2c_bus->mode = BYTE_MODE;
> > > > 		else
> > > > 			i2c_bus->buf_size = resource_size(res) / 2;
> 
> --
> With Best Regards,
> Andy Shevchenko
>
Andy Shevchenko Aug. 28, 2024, 1:55 p.m. UTC | #6
On Wed, Aug 28, 2024 at 02:34:43AM +0000, Ryan Chen wrote:
> > On Mon, Aug 26, 2024 at 07:50:24AM +0000, Ryan Chen wrote:
> > > > On Fri, Aug 23, 2024 at 06:23:54AM +0000, Ryan Chen wrote:
> > > > > > On Thu, Aug 22, 2024 at 02:24:26AM +0000, Ryan Chen wrote:
> > > > > > > > On Wed, Aug 21, 2024 at 06:43:01AM +0000, Ryan Chen wrote:
> > > > > > > > > > On Mon, Aug 19, 2024 at 05:28:49PM +0800, Ryan Chen wrote:

...

> > > > > > > > > > > +	if (i2c_bus->mode == BUFF_MODE) {
> > > > > > > > > > > +		i2c_bus->buf_base =
> > > > > > > > > > devm_platform_get_and_ioremap_resource(pdev, 1, &res);
> > > > > > > > > > > +		if (!IS_ERR_OR_NULL(i2c_bus->buf_base))
> > > > > > > > > > > +			i2c_bus->buf_size = resource_size(res) / 2;
> > > > > > > > > > > +		else
> > > > > > > > > > > +			i2c_bus->mode = BYTE_MODE;
> > > > > > > > > >
> > > > > > > > > > What's wrong with positive conditional? And is it even
> > > > > > > > > > possible to have NULL here?
> > > > > > > > > >
> > > > > > > > > Yes, if dtsi fill not following yaml example have reg 1,
> > > > > > > > > that will failure at buffer
> > > > > > > > mode.
> > > > > > > > > And I can swith to byte mode.
> > > > > > > > >
> > > > > > > > > reg = <0x80 0x80>, <0xc00 0x20>;
> > > > > > > >
> > > > > > > > I was asking about if (!IS_ERR_OR_NULL(...)) line:
> > > > > > > > 1) Why 'if (!foo) {} else {}' instead of 'if (foo) {} else {}'?
> > > > > > > I will update to following.
> > > > > > > 		if (IS_ERR(i2c_bus->buf_base))
> > > > > > > 			i2c_bus->mode = BYTE_MODE;
> > > > > > > 		else
> > > > > > > 			i2c_bus->buf_size = resource_size(res) / 2;
> > > > > > >
> > > > > > > > 2) Why _NULL?
> > > > > > > 	If dtsi file is claim only 1 reg offset. reg = <0x80 0x80>;
> > > > > > > that will goto byte
> > > > > > mode.
> > > > > > > 	reg = <0x80 0x80>, <0xc00 0x20>; can support buffer mode.
> > > > > > > 	due to 2nd is buffer register offset.
> > > > > >
> > > > > > I have asked why IS_ERR_OR_NULL() and not IS_ERR().
> > > > > >
> > > > > OH, I will doing by this.
> > > > > 		if (IS_ERR_OR_NULL(i2c_bus->buf_base))
> > > >
> > > > The question about _NULL remains unanswered...
> > > Sorry, I may not catch your point.
> > > So, Do you mean I should passive coding by following?
> > 
> > No. I already mentioned that in one of the previous mails.
> > Why do you use IS_ERR_OR_NULL() and not IS_ERR()?
> > 
> > You should understand your code better than me :-)
> Understood, I will change to 

OK!

> 	if (IS_ERR(i2c_bus->buf_base))
> 		i2c_bus->mode = BYTE_MODE;
> 	else
> 		i2c_bus->buf_size = resource_size(res) / 2;
> 
> > > If (i2c_bus->buf_base > 0)
> > > 	i2c_bus->buf_size = resource_size(res) / 2; else
> > >     i2c_bus->mode = BYTE_MODE;
> > >
> > > > > 			i2c_bus->mode = BYTE_MODE;
> > > > > 		else
> > > > > 			i2c_bus->buf_size = resource_size(res) / 2;
diff mbox series

Patch

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index a22f9125322a..abfb027350d4 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -410,6 +410,17 @@  config I2C_ALTERA
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-altera.
 
+config I2C_AST2600
+	tristate "Aspeed I2C v2 Controller"
+	depends on ARCH_ASPEED || COMPILE_TEST
+	select I2C_SMBUS
+	help
+	  If you say yes to this option, support will be included for the
+	  Aspeed I2C controller with new register set.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-ast2600.
+
 config I2C_ASPEED
 	tristate "Aspeed I2C Controller"
 	depends on ARCH_ASPEED || COMPILE_TEST
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 78d0561339e5..5665b60b1566 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -39,6 +39,7 @@  obj-$(CONFIG_I2C_POWERMAC)	+= i2c-powermac.o
 obj-$(CONFIG_I2C_ALTERA)	+= i2c-altera.o
 obj-$(CONFIG_I2C_AMD_MP2)	+= i2c-amd-mp2-pci.o i2c-amd-mp2-plat.o
 obj-$(CONFIG_I2C_ASPEED)	+= i2c-aspeed.o
+obj-$(CONFIG_I2C_AST2600)	+= i2c-ast2600.o
 obj-$(CONFIG_I2C_AT91)		+= i2c-at91.o
 i2c-at91-objs			:= i2c-at91-core.o i2c-at91-master.o
 ifeq ($(CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL),y)
diff --git a/drivers/i2c/busses/i2c-ast2600.c b/drivers/i2c/busses/i2c-ast2600.c
new file mode 100644
index 000000000000..c9b6013746a3
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ast2600.c
@@ -0,0 +1,1057 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ASPEED AST2600 new register set I2C controller driver
+ *
+ * Copyright (C) ASPEED Technology Inc.
+ */
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/string_helpers.h>
+
+#define AST2600_I2CG_ISR			0x00
+#define AST2600_I2CG_SLAVE_ISR		0x04
+#define AST2600_I2CG_OWNER		0x08
+#define AST2600_I2CG_CTRL		0x0C
+#define AST2600_I2CG_CLK_DIV_CTRL	0x10
+
+#define AST2600_I2CG_SLAVE_PKT_NAK	BIT(4)
+#define AST2600_I2CG_M_S_SEPARATE_INTR	BIT(3)
+#define AST2600_I2CG_CTRL_NEW_REG	BIT(2)
+#define AST2600_I2CG_CTRL_NEW_CLK_DIV	BIT(1)
+#define AST2600_GLOBAL_INIT	\
+	(AST2600_I2CG_CTRL_NEW_REG | AST2600_I2CG_CTRL_NEW_CLK_DIV)
+/*
+ * APB clk : 100Mhz
+ * div	: scl		: baseclk [APB/((div/2) + 1)] : tBuf [1/bclk * 16]
+ * I2CG10[31:24] base clk4 for i2c auto recovery timeout counter (0xC6)
+ * I2CG10[23:16] base clk3 for Standard-mode (100Khz) min tBuf 4.7us
+ * 0x3c : 100.8Khz	: 3.225Mhz					  : 4.96us
+ * 0x3d : 99.2Khz	: 3.174Mhz					  : 5.04us
+ * 0x3e : 97.65Khz	: 3.125Mhz					  : 5.12us
+ * 0x40 : 97.75Khz	: 3.03Mhz					  : 5.28us
+ * 0x41 : 99.5Khz	: 2.98Mhz					  : 5.36us (default)
+ * I2CG10[15:8] base clk2 for Fast-mode (400Khz) min tBuf 1.3us
+ * 0x12 : 400Khz	: 10Mhz						  : 1.6us
+ * I2CG10[7:0] base clk1 for Fast-mode Plus (1Mhz) min tBuf 0.5us
+ * 0x08 : 1Mhz		: 20Mhz						  : 0.8us
+ */
+#define I2CCG_DIV_CTRL 0xC6411208
+
+/* 0x00 : I2CC Master/Slave Function Control Register  */
+#define AST2600_I2CC_FUN_CTRL		0x00
+#define AST2600_I2CC_SLAVE_ADDR_RX_EN		BIT(20)
+#define AST2600_I2CC_MASTER_RETRY_MASK		GENMASK(19, 18)
+#define AST2600_I2CC_MASTER_RETRY(x)		(((x) & GENMASK(1, 0)) << 18)
+#define AST2600_I2CC_BUS_AUTO_RELEASE		BIT(17)
+#define AST2600_I2CC_M_SDA_LOCK_EN			BIT(16)
+#define AST2600_I2CC_MULTI_MASTER_DIS		BIT(15)
+#define AST2600_I2CC_M_SCL_DRIVE_EN			BIT(14)
+#define AST2600_I2CC_MSB_STS				BIT(9)
+#define AST2600_I2CC_SDA_DRIVE_1T_EN		BIT(8)
+#define AST2600_I2CC_M_SDA_DRIVE_1T_EN		BIT(7)
+#define AST2600_I2CC_M_HIGH_SPEED_EN		BIT(6)
+/* reserver 5 : 2 */
+#define AST2600_I2CC_SLAVE_EN			BIT(1)
+#define AST2600_I2CC_MASTER_EN			BIT(0)
+
+/* 0x04 : I2CC Master/Slave Clock and AC Timing Control Register #1 */
+#define AST2600_I2CC_AC_TIMING		0x04
+#define AST2600_I2CC_TTIMEOUT(x)			(((x) & GENMASK(4, 0)) << 24)
+#define AST2600_I2CC_TCKHIGHMIN(x)			(((x) & GENMASK(3, 0)) << 20)
+#define AST2600_I2CC_TCKHIGH(x)			(((x) & GENMASK(3, 0)) << 16)
+#define AST2600_I2CC_TCKLOW(x)			(((x) & GENMASK(3, 0)) << 12)
+#define AST2600_I2CC_THDDAT(x)			(((x) & GENMASK(1, 0)) << 10)
+#define AST2600_I2CC_TOUTBASECLK(x)			(((x) & GENMASK(1, 0)) << 8)
+#define AST2600_I2CC_TBASECLK(x)			((x) & GENMASK(3, 0))
+
+/* 0x08 : I2CC Master/Slave Transmit/Receive Byte Buffer Register */
+#define AST2600_I2CC_STS_AND_BUFF		0x08
+#define AST2600_I2CC_TX_DIR_MASK			GENMASK(31, 29)
+#define AST2600_I2CC_SDA_OE				BIT(28)
+#define AST2600_I2CC_SDA_O				BIT(27)
+#define AST2600_I2CC_SCL_OE				BIT(26)
+#define AST2600_I2CC_SCL_O				BIT(25)
+
+#define AST2600_I2CC_SCL_LINE_STS			BIT(18)
+#define AST2600_I2CC_SDA_LINE_STS			BIT(17)
+#define AST2600_I2CC_BUS_BUSY_STS			BIT(16)
+
+#define AST2600_I2CC_GET_RX_BUFF(x)			(((x) >> 8) & GENMASK(7, 0))
+
+/* 0x0C : I2CC Master/Slave Pool Buffer Control Register  */
+#define AST2600_I2CC_BUFF_CTRL		0x0C
+#define AST2600_I2CC_GET_RX_BUF_LEN(x)      (((x) & GENMASK(29, 24)) >> 24)
+#define AST2600_I2CC_SET_RX_BUF_LEN(x)		(((((x) - 1) & GENMASK(4, 0)) << 16) | BIT(0))
+#define AST2600_I2CC_SET_TX_BUF_LEN(x)		(((((x) - 1) & GENMASK(4, 0)) << 8) | BIT(0))
+#define AST2600_I2CC_GET_TX_BUF_LEN(x)      ((((x) & GENMASK(12, 8)) >> 8) + 1)
+
+/* 0x10 : I2CM Master Interrupt Control Register */
+#define AST2600_I2CM_IER			0x10
+/* 0x14 : I2CM Master Interrupt Status Register   : WC */
+#define AST2600_I2CM_ISR			0x14
+
+#define AST2600_I2CM_PKT_TIMEOUT			BIT(18)
+#define AST2600_I2CM_PKT_ERROR			BIT(17)
+#define AST2600_I2CM_PKT_DONE			BIT(16)
+
+#define AST2600_I2CM_BUS_RECOVER_FAIL		BIT(15)
+#define AST2600_I2CM_SDA_DL_TO			BIT(14)
+#define AST2600_I2CM_BUS_RECOVER			BIT(13)
+#define AST2600_I2CM_SMBUS_ALT			BIT(12)
+
+#define AST2600_I2CM_SCL_LOW_TO			BIT(6)
+#define AST2600_I2CM_ABNORMAL			BIT(5)
+#define AST2600_I2CM_NORMAL_STOP			BIT(4)
+#define AST2600_I2CM_ARBIT_LOSS			BIT(3)
+#define AST2600_I2CM_RX_DONE			BIT(2)
+#define AST2600_I2CM_TX_NAK				BIT(1)
+#define AST2600_I2CM_TX_ACK				BIT(0)
+
+/* 0x18 : I2CM Master Command/Status Register   */
+#define AST2600_I2CM_CMD_STS		0x18
+#define AST2600_I2CM_PKT_ADDR(x)			(((x) & GENMASK(6, 0)) << 24)
+#define AST2600_I2CM_PKT_EN				BIT(16)
+#define AST2600_I2CM_SDA_OE_OUT_DIR			BIT(15)
+#define AST2600_I2CM_SDA_O_OUT_DIR			BIT(14)
+#define AST2600_I2CM_SCL_OE_OUT_DIR			BIT(13)
+#define AST2600_I2CM_SCL_O_OUT_DIR			BIT(12)
+#define AST2600_I2CM_RECOVER_CMD_EN			BIT(11)
+
+#define AST2600_I2CM_RX_DMA_EN			BIT(9)
+#define AST2600_I2CM_TX_DMA_EN			BIT(8)
+/* Command Bit */
+#define AST2600_I2CM_RX_BUFF_EN			BIT(7)
+#define AST2600_I2CM_TX_BUFF_EN			BIT(6)
+#define AST2600_I2CM_STOP_CMD			BIT(5)
+#define AST2600_I2CM_RX_CMD_LAST			BIT(4)
+#define AST2600_I2CM_RX_CMD				BIT(3)
+
+#define AST2600_I2CM_TX_CMD				BIT(1)
+#define AST2600_I2CM_START_CMD			BIT(0)
+
+/* 0x1C : I2CM Master DMA Transfer Length Register	 */
+#define AST2600_I2CM_DMA_LEN		0x1C
+/* Tx Rx support length 1 ~ 4096 */
+#define AST2600_I2CM_SET_RX_DMA_LEN(x)	((((x) & GENMASK(11, 0)) << 16) | BIT(31))
+#define AST2600_I2CM_SET_TX_DMA_LEN(x)	(((x) & GENMASK(11, 0)) | BIT(15))
+
+/* 0x20 : I2CS Slave Interrupt Control Register   */
+#define AST2600_I2CS_IER			0x20
+/* 0x24 : I2CS Slave Interrupt Status Register	 */
+#define AST2600_I2CS_ISR			0x24
+
+#define AST2600_I2CS_ADDR_INDICATE_MASK	GENMASK(31, 30)
+#define AST2600_I2CS_SLAVE_PENDING			BIT(29)
+
+#define AST2600_I2CS_WAIT_TX_DMA			BIT(25)
+#define AST2600_I2CS_WAIT_RX_DMA			BIT(24)
+
+#define AST2600_I2CS_ADDR3_NAK			BIT(22)
+#define AST2600_I2CS_ADDR2_NAK			BIT(21)
+#define AST2600_I2CS_ADDR1_NAK			BIT(20)
+
+#define AST2600_I2CS_ADDR_MASK			GENMASK(19, 18)
+#define AST2600_I2CS_PKT_ERROR			BIT(17)
+#define AST2600_I2CS_PKT_DONE			BIT(16)
+#define AST2600_I2CS_INACTIVE_TO			BIT(15)
+
+#define AST2600_I2CS_SLAVE_MATCH			BIT(7)
+#define AST2600_I2CS_ABNOR_STOP			BIT(5)
+#define AST2600_I2CS_STOP				BIT(4)
+#define AST2600_I2CS_RX_DONE_NAK			BIT(3)
+#define AST2600_I2CS_RX_DONE			BIT(2)
+#define AST2600_I2CS_TX_NAK				BIT(1)
+#define AST2600_I2CS_TX_ACK				BIT(0)
+
+/* 0x28 : I2CS Slave CMD/Status Register   */
+#define AST2600_I2CS_CMD_STS		0x28
+#define AST2600_I2CS_ACTIVE_ALL			GENMASK(18, 17)
+#define AST2600_I2CS_PKT_MODE_EN			BIT(16)
+#define AST2600_I2CS_AUTO_NAK_NOADDR		BIT(15)
+#define AST2600_I2CS_AUTO_NAK_EN			BIT(14)
+
+#define AST2600_I2CS_ALT_EN				BIT(10)
+#define AST2600_I2CS_RX_DMA_EN			BIT(9)
+#define AST2600_I2CS_TX_DMA_EN			BIT(8)
+#define AST2600_I2CS_RX_BUFF_EN			BIT(7)
+#define AST2600_I2CS_TX_BUFF_EN			BIT(6)
+#define AST2600_I2CS_RX_CMD_LAST			BIT(4)
+
+#define AST2600_I2CS_TX_CMD				BIT(2)
+
+#define AST2600_I2CS_DMA_LEN		0x2C
+#define AST2600_I2CS_SET_RX_DMA_LEN(x)	(((((x) - 1) & GENMASK(11, 0)) << 16) | BIT(31))
+#define AST2600_I2CS_SET_TX_DMA_LEN(x)	((((x) - 1) & GENMASK(11, 0)) | BIT(15))
+
+/* I2CM Master DMA Tx Buffer Register   */
+#define AST2600_I2CM_TX_DMA			0x30
+/* I2CM Master DMA Rx Buffer Register	*/
+#define AST2600_I2CM_RX_DMA			0x34
+/* I2CS Slave DMA Tx Buffer Register   */
+#define AST2600_I2CS_TX_DMA			0x38
+/* I2CS Slave DMA Rx Buffer Register   */
+#define AST2600_I2CS_RX_DMA			0x3C
+
+#define AST2600_I2CS_ADDR_CTRL		0x40
+
+#define	AST2600_I2CS_ADDR3_MASK		GENMASK(22, 16)
+#define	AST2600_I2CS_ADDR2_MASK		GENMASK(14, 8)
+#define	AST2600_I2CS_ADDR1_MASK		GENMASK(6, 0)
+
+#define AST2600_I2CM_DMA_LEN_STS		0x48
+#define AST2600_I2CS_DMA_LEN_STS		0x4C
+
+#define AST2600_I2C_GET_TX_DMA_LEN(x)		((x) & GENMASK(12, 0))
+#define AST2600_I2C_GET_RX_DMA_LEN(x)        (((x) & GENMASK(28, 16)) >> 16)
+
+/* 0x40 : Slave Device Address Register */
+#define AST2600_I2CS_ADDR3_ENABLE			BIT(23)
+#define AST2600_I2CS_ADDR3(x)			((x) << 16)
+#define AST2600_I2CS_ADDR2_ENABLE			BIT(15)
+#define AST2600_I2CS_ADDR2(x)			((x) << 8)
+#define AST2600_I2CS_ADDR1_ENABLE			BIT(7)
+#define AST2600_I2CS_ADDR1(x)			(x)
+
+#define I2C_SLAVE_MSG_BUF_SIZE		256
+
+#define AST2600_I2C_DMA_SIZE		4096
+
+#define MASTER_TRIGGER_LAST_STOP	(AST2600_I2CM_RX_CMD_LAST | AST2600_I2CM_STOP_CMD)
+#define SLAVE_TRIGGER_CMD	(AST2600_I2CS_ACTIVE_ALL | AST2600_I2CS_PKT_MODE_EN)
+
+#define AST_I2C_TIMEOUT_CLK		0x2
+
+enum xfer_mode {
+	BYTE_MODE,
+	BUFF_MODE,
+	DMA_MODE,
+};
+
+struct ast2600_i2c_bus {
+	struct i2c_adapter		adap;
+	struct device			*dev;
+	void __iomem			*reg_base;
+	struct regmap			*global_regs;
+	struct reset_control		*rst;
+	int				irq;
+	enum xfer_mode			mode;
+	struct clk			*clk;
+	u32				apb_clk;
+	struct i2c_timings		timing_info;
+	u32				timeout;
+	/* smbus alert */
+	bool			alert_enable;
+	struct i2c_smbus_alert_setup	alert_data;
+	struct i2c_client		*ara;
+	/* Multi-master */
+	bool				multi_master;
+	/* master structure */
+	int				cmd_err;
+	struct completion		cmd_complete;
+	struct i2c_msg			*msgs;
+	size_t				buf_index;
+	/* cur xfer msgs index*/
+	int				msgs_index;
+	int				msgs_count;
+	u8				*master_safe_buf;
+	dma_addr_t			master_dma_addr;
+	/*total xfer count */
+	int				master_xfer_cnt;
+	/* Buffer mode */
+	void __iomem			*buf_base;
+	size_t				buf_size;
+};
+
+static u32 ast2600_select_i2c_clock(struct ast2600_i2c_bus *i2c_bus)
+{
+	unsigned long base_clk[16];
+	int baseclk_idx;
+	u32 clk_div_reg;
+	u32 scl_low;
+	u32 scl_high;
+	int divisor;
+	u32 data;
+
+	regmap_read(i2c_bus->global_regs, AST2600_I2CG_CLK_DIV_CTRL, &clk_div_reg);
+
+	for (int i = 0; i < 16; i++) {
+		if (i == 0)
+			base_clk[i] = i2c_bus->apb_clk;
+		else if ((i > 0) || (i < 5))
+			base_clk[i] = (i2c_bus->apb_clk * 2) /
+				(((clk_div_reg >> ((i - 1) * 8)) & GENMASK(7, 0)) + 2);
+		else
+			base_clk[i] = base_clk[4] / (1 << (i - 5));
+
+		if ((base_clk[i] / i2c_bus->timing_info.bus_freq_hz) <= 32) {
+			baseclk_idx = i;
+			divisor = DIV_ROUND_UP(base_clk[i], i2c_bus->timing_info.bus_freq_hz);
+			break;
+		}
+	}
+	baseclk_idx = min(baseclk_idx, 15);
+	divisor = min(divisor, 32);
+	scl_low = min(divisor * 9 / 16 - 1, 15);
+	scl_high = (divisor - scl_low - 2) & GENMASK(3, 0);
+	data = (scl_high - 1) << 20 | scl_high << 16 | scl_low << 12 | baseclk_idx;
+	if (i2c_bus->timeout) {
+		data |= AST2600_I2CC_TOUTBASECLK(AST_I2C_TIMEOUT_CLK);
+		data |= AST2600_I2CC_TTIMEOUT(i2c_bus->timeout);
+	}
+
+	return data;
+}
+
+static u8 ast2600_i2c_recover_bus(struct ast2600_i2c_bus *i2c_bus)
+{
+	u32 state = readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
+	int ret = 0;
+	u32 ctrl;
+	int r;
+
+	dev_dbg(i2c_bus->dev, "%d-bus recovery bus [%x]\n", i2c_bus->adap.nr, state);
+
+	ctrl = readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+	/* Disable master/slave mode */
+	writel(ctrl & ~(AST2600_I2CC_MASTER_EN | AST2600_I2CC_SLAVE_EN),
+	       i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+	/* Enable master mode only */
+	writel(readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL) | AST2600_I2CC_MASTER_EN,
+	       i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+	reinit_completion(&i2c_bus->cmd_complete);
+	i2c_bus->cmd_err = 0;
+
+	/* Check 0x14's SDA and SCL status */
+	state = readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
+	if (!(state & AST2600_I2CC_SDA_LINE_STS) && (state & AST2600_I2CC_SCL_LINE_STS)) {
+		writel(AST2600_I2CM_RECOVER_CMD_EN, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+		r = wait_for_completion_timeout(&i2c_bus->cmd_complete, i2c_bus->adap.timeout);
+		if (r == 0) {
+			dev_dbg(i2c_bus->dev, "recovery timed out\n");
+			ret = -ETIMEDOUT;
+		} else {
+			if (i2c_bus->cmd_err) {
+				dev_dbg(i2c_bus->dev, "recovery error\n");
+				ret = -EPROTO;
+			}
+		}
+	}
+
+	/* Recovery done */
+	state = readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
+	if (state & AST2600_I2CC_BUS_BUSY_STS) {
+		dev_dbg(i2c_bus->dev, "Can't recover bus [%x]\n", state);
+		ret = -EPROTO;
+	}
+
+	/* restore original master/slave setting */
+	writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+	return ret;
+}
+
+static int ast2600_i2c_setup_dma_tx(u32 cmd, struct ast2600_i2c_bus *i2c_bus)
+{
+	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];
+	int xfer_len;
+
+	cmd |= AST2600_I2CM_PKT_EN;
+	xfer_len = msg->len - i2c_bus->master_xfer_cnt;
+	if (xfer_len > AST2600_I2C_DMA_SIZE) {
+		xfer_len = AST2600_I2C_DMA_SIZE;
+	} else {
+		if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+			cmd |= AST2600_I2CM_STOP_CMD;
+	}
+
+	if (cmd & AST2600_I2CM_START_CMD) {
+		cmd |= AST2600_I2CM_PKT_ADDR(msg->addr);
+		i2c_bus->master_safe_buf = i2c_get_dma_safe_msg_buf(msg, 1);
+		if (!i2c_bus->master_safe_buf)
+			return -ENOMEM;
+		i2c_bus->master_dma_addr =
+			dma_map_single(i2c_bus->dev, i2c_bus->master_safe_buf,
+				       msg->len, DMA_TO_DEVICE);
+		if (dma_mapping_error(i2c_bus->dev, i2c_bus->master_dma_addr)) {
+			i2c_put_dma_safe_msg_buf(i2c_bus->master_safe_buf, msg, false);
+			i2c_bus->master_safe_buf = NULL;
+			return -ENOMEM;
+		}
+	}
+
+	if (xfer_len) {
+		cmd |= AST2600_I2CM_TX_DMA_EN | AST2600_I2CM_TX_CMD;
+		writel(AST2600_I2CM_SET_TX_DMA_LEN(xfer_len - 1),
+		       i2c_bus->reg_base + AST2600_I2CM_DMA_LEN);
+		writel(i2c_bus->master_dma_addr + i2c_bus->master_xfer_cnt,
+		       i2c_bus->reg_base + AST2600_I2CM_TX_DMA);
+	}
+
+	writel(cmd, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+
+	return 0;
+}
+
+static int ast2600_i2c_setup_buff_tx(u32 cmd, struct ast2600_i2c_bus *i2c_bus)
+{
+	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];
+	u32 wbuf_dword;
+	int xfer_len;
+	u8 wbuf[4];
+	int i;
+
+	cmd |= AST2600_I2CM_PKT_EN;
+	xfer_len = msg->len - i2c_bus->master_xfer_cnt;
+	if (xfer_len > i2c_bus->buf_size) {
+		xfer_len = i2c_bus->buf_size;
+	} else {
+		if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+			cmd |= AST2600_I2CM_STOP_CMD;
+	}
+
+	if (cmd & AST2600_I2CM_START_CMD)
+		cmd |= AST2600_I2CM_PKT_ADDR(msg->addr);
+
+	if (xfer_len) {
+		cmd |= AST2600_I2CM_TX_BUFF_EN | AST2600_I2CM_TX_CMD;
+		/*
+		 * The controller's buffer register supports dword writes only.
+		 * Therefore, write dwords to the buffer register in a 4-byte aligned,
+		 * and write the remaining unaligned data at the end.
+		 */
+		for (i = 0; i < xfer_len; i++) {
+			wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
+			if ((i % 4) == 3 || i == xfer_len - 1) {
+				wbuf_dword = get_unaligned_le32(wbuf);
+				writel(wbuf_dword, i2c_bus->buf_base + i - (i % 4));
+			}
+		}
+
+		writel(AST2600_I2CC_SET_TX_BUF_LEN(xfer_len),
+		       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+	}
+
+	writel(cmd, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+
+	return 0;
+}
+
+static int ast2600_i2c_setup_byte_tx(u32 cmd, struct ast2600_i2c_bus *i2c_bus)
+{
+	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];
+	int xfer_len;
+
+	xfer_len = msg->len - i2c_bus->master_xfer_cnt;
+
+	cmd |= AST2600_I2CM_PKT_EN;
+
+	if (cmd & AST2600_I2CM_START_CMD)
+		cmd |= AST2600_I2CM_PKT_ADDR(msg->addr);
+
+	if ((i2c_bus->msgs_index + 1 == i2c_bus->msgs_count) &&
+	    ((i2c_bus->master_xfer_cnt + 1) == msg->len))
+		cmd |= AST2600_I2CM_STOP_CMD;
+
+	if (xfer_len) {
+		cmd |= AST2600_I2CM_TX_CMD;
+		writel(msg->buf[i2c_bus->master_xfer_cnt],
+		       i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
+	}
+
+	writel(cmd, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+
+	return 0;
+}
+
+static int ast2600_i2c_setup_dma_rx(struct ast2600_i2c_bus *i2c_bus)
+{
+	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];
+	int xfer_len;
+	u32 cmd;
+
+	cmd = AST2600_I2CM_PKT_EN | AST2600_I2CM_PKT_ADDR(msg->addr) |
+	      AST2600_I2CM_START_CMD | AST2600_I2CM_RX_DMA_EN;
+
+	if (msg->flags & I2C_M_RECV_LEN) {
+		xfer_len = 1;
+	} else {
+		if (msg->len > AST2600_I2C_DMA_SIZE) {
+			xfer_len = AST2600_I2C_DMA_SIZE;
+		} else {
+			xfer_len = msg->len;
+			if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+				cmd |= MASTER_TRIGGER_LAST_STOP;
+		}
+	}
+	writel(AST2600_I2CM_SET_RX_DMA_LEN(xfer_len - 1), i2c_bus->reg_base + AST2600_I2CM_DMA_LEN);
+	i2c_bus->master_safe_buf = i2c_get_dma_safe_msg_buf(msg, 1);
+	if (!i2c_bus->master_safe_buf)
+		return -ENOMEM;
+	i2c_bus->master_dma_addr =
+		dma_map_single(i2c_bus->dev, i2c_bus->master_safe_buf, msg->len, DMA_FROM_DEVICE);
+	if (dma_mapping_error(i2c_bus->dev, i2c_bus->master_dma_addr)) {
+		i2c_put_dma_safe_msg_buf(i2c_bus->master_safe_buf, msg, false);
+		i2c_bus->master_safe_buf = NULL;
+		return -ENOMEM;
+	}
+	writel(i2c_bus->master_dma_addr, i2c_bus->reg_base + AST2600_I2CM_RX_DMA);
+
+	writel(cmd, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+
+	return 0;
+}
+
+static int ast2600_i2c_setup_buff_rx(struct ast2600_i2c_bus *i2c_bus)
+{
+	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];
+	int xfer_len;
+	u32 cmd;
+
+	cmd = AST2600_I2CM_PKT_EN | AST2600_I2CM_PKT_ADDR(msg->addr) |
+	      AST2600_I2CM_START_CMD | AST2600_I2CM_RX_BUFF_EN;
+
+	if (msg->flags & I2C_M_RECV_LEN) {
+		dev_dbg(i2c_bus->dev, "smbus read\n");
+		xfer_len = 1;
+	} else {
+		if (msg->len > i2c_bus->buf_size) {
+			xfer_len = i2c_bus->buf_size;
+		} else {
+			xfer_len = msg->len;
+			if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+				cmd |= MASTER_TRIGGER_LAST_STOP;
+		}
+	}
+	writel(AST2600_I2CC_SET_RX_BUF_LEN(xfer_len), i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+
+	writel(cmd, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+
+	return 0;
+}
+
+static int ast2600_i2c_setup_byte_rx(struct ast2600_i2c_bus *i2c_bus)
+{
+	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];
+	u32 cmd;
+
+	cmd = AST2600_I2CM_PKT_EN | AST2600_I2CM_PKT_ADDR(msg->addr) |
+	      AST2600_I2CM_START_CMD | AST2600_I2CM_RX_CMD;
+
+	if (msg->flags & I2C_M_RECV_LEN) {
+		dev_dbg(i2c_bus->dev, "smbus read\n");
+	} else {
+		if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count) {
+			if (msg->len == 1)
+				cmd |= MASTER_TRIGGER_LAST_STOP;
+		}
+	}
+
+	writel(cmd, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+
+	return 0;
+}
+
+static int ast2600_i2c_do_start(struct ast2600_i2c_bus *i2c_bus)
+{
+	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];
+
+	/* send start */
+	dev_dbg(i2c_bus->dev, "[%d] %sing %d byte%s %s 0x%02x\n",
+		i2c_bus->msgs_index, str_read_write(msg->flags & I2C_M_RD),
+		msg->len, msg->len > 1 ? "s" : "",
+		msg->flags & I2C_M_RD ? "from" : "to", msg->addr);
+
+	i2c_bus->master_xfer_cnt = 0;
+	i2c_bus->buf_index = 0;
+
+	if (msg->flags & I2C_M_RD) {
+		if (i2c_bus->mode == DMA_MODE)
+			return ast2600_i2c_setup_dma_rx(i2c_bus);
+		else if (i2c_bus->mode == BUFF_MODE)
+			return ast2600_i2c_setup_buff_rx(i2c_bus);
+		else
+			return ast2600_i2c_setup_byte_rx(i2c_bus);
+	} else {
+		if (i2c_bus->mode == DMA_MODE)
+			return ast2600_i2c_setup_dma_tx(AST2600_I2CM_START_CMD, i2c_bus);
+		else if (i2c_bus->mode == BUFF_MODE)
+			return ast2600_i2c_setup_buff_tx(AST2600_I2CM_START_CMD, i2c_bus);
+		else
+			return ast2600_i2c_setup_byte_tx(AST2600_I2CM_START_CMD, i2c_bus);
+	}
+}
+
+static int ast2600_i2c_irq_err_to_errno(u32 irq_status)
+{
+	if (irq_status & AST2600_I2CM_ARBIT_LOSS)
+		return -EAGAIN;
+	if (irq_status & (AST2600_I2CM_SDA_DL_TO | AST2600_I2CM_SCL_LOW_TO))
+		return -EBUSY;
+	if (irq_status & (AST2600_I2CM_ABNORMAL))
+		return -EPROTO;
+
+	return 0;
+}
+
+static void ast2600_i2c_master_package_irq(struct ast2600_i2c_bus *i2c_bus, u32 sts)
+{
+	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];
+	u32 cmd = AST2600_I2CM_PKT_EN;
+	int xfer_len;
+	int i;
+
+	sts &= ~AST2600_I2CM_PKT_DONE;
+	writel(AST2600_I2CM_PKT_DONE, i2c_bus->reg_base + AST2600_I2CM_ISR);
+	switch (sts) {
+	case AST2600_I2CM_PKT_ERROR:
+		i2c_bus->cmd_err = -EAGAIN;
+		complete(&i2c_bus->cmd_complete);
+		break;
+	case AST2600_I2CM_PKT_ERROR | AST2600_I2CM_TX_NAK: /* a0 fix for issue */
+		fallthrough;
+	case AST2600_I2CM_PKT_ERROR | AST2600_I2CM_TX_NAK | AST2600_I2CM_NORMAL_STOP:
+		i2c_bus->cmd_err = -ENXIO;
+		complete(&i2c_bus->cmd_complete);
+		break;
+	case AST2600_I2CM_NORMAL_STOP:
+		/* write 0 byte only have stop isr */
+		i2c_bus->msgs_index++;
+		if (i2c_bus->msgs_index < i2c_bus->msgs_count) {
+			if (ast2600_i2c_do_start(i2c_bus)) {
+				i2c_bus->cmd_err = -ENOMEM;
+				complete(&i2c_bus->cmd_complete);
+			}
+		} else {
+			i2c_bus->cmd_err = i2c_bus->msgs_index;
+			complete(&i2c_bus->cmd_complete);
+		}
+		break;
+	case AST2600_I2CM_TX_ACK:
+	case AST2600_I2CM_TX_ACK | AST2600_I2CM_NORMAL_STOP:
+		if (i2c_bus->mode == DMA_MODE)
+			xfer_len = AST2600_I2C_GET_TX_DMA_LEN(readl(i2c_bus->reg_base +
+							  AST2600_I2CM_DMA_LEN_STS));
+		else if (i2c_bus->mode == BUFF_MODE)
+			xfer_len = AST2600_I2CC_GET_TX_BUF_LEN(readl(i2c_bus->reg_base +
+							   AST2600_I2CC_BUFF_CTRL));
+		else
+			xfer_len = 1;
+
+		i2c_bus->master_xfer_cnt += xfer_len;
+
+		if (i2c_bus->master_xfer_cnt == msg->len) {
+			if (i2c_bus->mode == DMA_MODE) {
+				dma_unmap_single(i2c_bus->dev, i2c_bus->master_dma_addr, msg->len,
+						 DMA_TO_DEVICE);
+				i2c_put_dma_safe_msg_buf(i2c_bus->master_safe_buf, msg, true);
+				i2c_bus->master_safe_buf = NULL;
+			}
+			i2c_bus->msgs_index++;
+			if (i2c_bus->msgs_index == i2c_bus->msgs_count) {
+				i2c_bus->cmd_err = i2c_bus->msgs_index;
+				complete(&i2c_bus->cmd_complete);
+			} else {
+				if (ast2600_i2c_do_start(i2c_bus)) {
+					i2c_bus->cmd_err = -ENOMEM;
+					complete(&i2c_bus->cmd_complete);
+				}
+			}
+		} else {
+			if (i2c_bus->mode == DMA_MODE)
+				ast2600_i2c_setup_dma_tx(0, i2c_bus);
+			else if (i2c_bus->mode == BUFF_MODE)
+				ast2600_i2c_setup_buff_tx(0, i2c_bus);
+			else
+				ast2600_i2c_setup_byte_tx(0, i2c_bus);
+		}
+		break;
+	case AST2600_I2CM_RX_DONE:
+	case AST2600_I2CM_RX_DONE | AST2600_I2CM_NORMAL_STOP:
+		/* do next rx */
+		if (i2c_bus->mode == DMA_MODE) {
+			xfer_len = AST2600_I2C_GET_RX_DMA_LEN(readl(i2c_bus->reg_base +
+								    AST2600_I2CM_DMA_LEN_STS));
+		} else if (i2c_bus->mode == BUFF_MODE) {
+			xfer_len = AST2600_I2CC_GET_RX_BUF_LEN(readl(i2c_bus->reg_base +
+								     AST2600_I2CC_BUFF_CTRL));
+			for (i = 0; i < xfer_len; i++)
+				msg->buf[i2c_bus->master_xfer_cnt + i] =
+					readb(i2c_bus->buf_base + 0x10 + i);
+		} else {
+			xfer_len = 1;
+			msg->buf[i2c_bus->master_xfer_cnt] =
+				AST2600_I2CC_GET_RX_BUFF(readl(i2c_bus->reg_base +
+						     AST2600_I2CC_STS_AND_BUFF));
+		}
+
+		if (msg->flags & I2C_M_RECV_LEN) {
+			msg->len = min_t(unsigned int, msg->buf[0], I2C_SMBUS_BLOCK_MAX);
+			msg->len += ((msg->flags & I2C_CLIENT_PEC) ? 2 : 1);
+			msg->flags &= ~I2C_M_RECV_LEN;
+		}
+		i2c_bus->master_xfer_cnt += xfer_len;
+
+		if (i2c_bus->master_xfer_cnt == msg->len) {
+			if (i2c_bus->mode == DMA_MODE) {
+				dma_unmap_single(i2c_bus->dev, i2c_bus->master_dma_addr, msg->len,
+						 DMA_FROM_DEVICE);
+				i2c_put_dma_safe_msg_buf(i2c_bus->master_safe_buf, msg, true);
+				i2c_bus->master_safe_buf = NULL;
+			}
+
+			i2c_bus->msgs_index++;
+			if (i2c_bus->msgs_index == i2c_bus->msgs_count) {
+				i2c_bus->cmd_err = i2c_bus->msgs_index;
+				complete(&i2c_bus->cmd_complete);
+			} else {
+				if (ast2600_i2c_do_start(i2c_bus)) {
+					i2c_bus->cmd_err = -ENOMEM;
+					complete(&i2c_bus->cmd_complete);
+				}
+			}
+		} else {
+			/* next rx */
+			cmd |= AST2600_I2CM_RX_CMD;
+			if (i2c_bus->mode == DMA_MODE) {
+				cmd |= AST2600_I2CM_RX_DMA_EN;
+				xfer_len = msg->len - i2c_bus->master_xfer_cnt;
+				if (xfer_len > AST2600_I2C_DMA_SIZE) {
+					xfer_len = AST2600_I2C_DMA_SIZE;
+				} else {
+					if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+						cmd |= MASTER_TRIGGER_LAST_STOP;
+				}
+				writel(AST2600_I2CM_SET_RX_DMA_LEN(xfer_len - 1),
+				       i2c_bus->reg_base + AST2600_I2CM_DMA_LEN);
+				writel(i2c_bus->master_dma_addr + i2c_bus->master_xfer_cnt,
+				       i2c_bus->reg_base + AST2600_I2CM_RX_DMA);
+			} else if (i2c_bus->mode == BUFF_MODE) {
+				cmd |= AST2600_I2CM_RX_BUFF_EN;
+				xfer_len = msg->len - i2c_bus->master_xfer_cnt;
+				if (xfer_len > i2c_bus->buf_size) {
+					xfer_len = i2c_bus->buf_size;
+				} else {
+					if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+						cmd |= MASTER_TRIGGER_LAST_STOP;
+				}
+				writel(AST2600_I2CC_SET_RX_BUF_LEN(xfer_len),
+				       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+			} else {
+				if ((i2c_bus->msgs_index + 1 == i2c_bus->msgs_count) &&
+				    ((i2c_bus->master_xfer_cnt + 1) == msg->len)) {
+					cmd |= MASTER_TRIGGER_LAST_STOP;
+				}
+			}
+			writel(cmd, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+		}
+		break;
+	default:
+		dev_dbg(i2c_bus->dev, "unhandled sts %x\n", sts);
+		break;
+	}
+}
+
+static int ast2600_i2c_master_irq(struct ast2600_i2c_bus *i2c_bus)
+{
+	u32 sts = readl(i2c_bus->reg_base + AST2600_I2CM_ISR);
+	u32 ier = readl(i2c_bus->reg_base + AST2600_I2CM_IER);
+	u32 ctrl;
+
+	if (!i2c_bus->alert_enable)
+		sts &= ~AST2600_I2CM_SMBUS_ALT;
+
+	if (AST2600_I2CM_BUS_RECOVER_FAIL & sts) {
+		writel(AST2600_I2CM_BUS_RECOVER_FAIL, i2c_bus->reg_base + AST2600_I2CM_ISR);
+		ctrl = readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+		writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+		writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+		i2c_bus->cmd_err = -EPROTO;
+		complete(&i2c_bus->cmd_complete);
+		return 1;
+	}
+
+	if (AST2600_I2CM_BUS_RECOVER & sts) {
+		writel(AST2600_I2CM_BUS_RECOVER, i2c_bus->reg_base + AST2600_I2CM_ISR);
+		i2c_bus->cmd_err = 0;
+		complete(&i2c_bus->cmd_complete);
+		return 1;
+	}
+
+	if (AST2600_I2CM_SMBUS_ALT & sts) {
+		if (ier & AST2600_I2CM_SMBUS_ALT) {
+			/* Disable ALT INT */
+			writel(ier & ~AST2600_I2CM_SMBUS_ALT, i2c_bus->reg_base + AST2600_I2CM_IER);
+			i2c_handle_smbus_alert(i2c_bus->ara);
+			writel(AST2600_I2CM_SMBUS_ALT, i2c_bus->reg_base + AST2600_I2CM_ISR);
+			dev_err(i2c_bus->dev,
+				"ast2600_master_alert_recv bus id %d, Disable Alt, Please Imple\n",
+				i2c_bus->adap.nr);
+			return 1;
+		}
+	}
+
+	i2c_bus->cmd_err = ast2600_i2c_irq_err_to_errno(sts);
+	if (i2c_bus->cmd_err) {
+		writel(AST2600_I2CM_PKT_DONE, i2c_bus->reg_base + AST2600_I2CM_ISR);
+		complete(&i2c_bus->cmd_complete);
+		return 1;
+	}
+
+	if (AST2600_I2CM_PKT_DONE & sts) {
+		ast2600_i2c_master_package_irq(i2c_bus, sts);
+		return 1;
+	}
+
+	return 0;
+}
+
+static irqreturn_t ast2600_i2c_bus_irq(int irq, void *dev_id)
+{
+	struct ast2600_i2c_bus *i2c_bus = dev_id;
+
+	return IRQ_RETVAL(ast2600_i2c_master_irq(i2c_bus));
+}
+
+static int ast2600_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+	struct ast2600_i2c_bus *i2c_bus = i2c_get_adapdata(adap);
+	unsigned long timeout;
+	int ret;
+
+	/* If bus is busy in a single master environment, attempt recovery. */
+	if (!i2c_bus->multi_master &&
+	    (readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF) & AST2600_I2CC_BUS_BUSY_STS)) {
+		ret = ast2600_i2c_recover_bus(i2c_bus);
+		if (ret)
+			return ret;
+	}
+
+	i2c_bus->cmd_err = 0;
+	i2c_bus->msgs = msgs;
+	i2c_bus->msgs_index = 0;
+	i2c_bus->msgs_count = num;
+	reinit_completion(&i2c_bus->cmd_complete);
+	ret = ast2600_i2c_do_start(i2c_bus);
+	if (ret)
+		goto master_out;
+	timeout = wait_for_completion_timeout(&i2c_bus->cmd_complete, i2c_bus->adap.timeout);
+	if (timeout == 0) {
+		u32 ctrl = readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+		dev_dbg(i2c_bus->dev, "timeout isr[%x], sts[%x]\n",
+			readl(i2c_bus->reg_base + AST2600_I2CM_ISR),
+			readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
+		writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+		writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+		if (i2c_bus->multi_master &&
+		    (readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF) &
+		    AST2600_I2CC_BUS_BUSY_STS))
+			ast2600_i2c_recover_bus(i2c_bus);
+
+		ret = -ETIMEDOUT;
+	} else {
+		ret = i2c_bus->cmd_err;
+	}
+
+	dev_dbg(i2c_bus->dev, "bus%d-m: %d end\n", i2c_bus->adap.nr, i2c_bus->cmd_err);
+
+master_out:
+	if (i2c_bus->mode == DMA_MODE) {
+		kfree(i2c_bus->master_safe_buf);
+	    i2c_bus->master_safe_buf = NULL;
+	}
+
+	return ret;
+}
+
+static void ast2600_i2c_init(struct ast2600_i2c_bus *i2c_bus)
+{
+	struct platform_device *pdev = to_platform_device(i2c_bus->dev);
+	u32 fun_ctrl = AST2600_I2CC_BUS_AUTO_RELEASE | AST2600_I2CC_MASTER_EN;
+
+	/* I2C Reset */
+	writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+	i2c_bus->multi_master = device_property_read_bool(&pdev->dev, "multi-master");
+	if (!i2c_bus->multi_master)
+		fun_ctrl |= AST2600_I2CC_MULTI_MASTER_DIS;
+
+	/* Enable Master Mode */
+	writel(fun_ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+	/* disable slave address */
+	writel(0, i2c_bus->reg_base + AST2600_I2CS_ADDR_CTRL);
+
+	/* Set AC Timing */
+	writel(ast2600_select_i2c_clock(i2c_bus), i2c_bus->reg_base + AST2600_I2CC_AC_TIMING);
+
+	/* Clear Interrupt */
+	writel(GENMASK(27, 0), i2c_bus->reg_base + AST2600_I2CM_ISR);
+}
+
+static u32 ast2600_i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+static const struct i2c_algorithm i2c_ast2600_algorithm = {
+	.master_xfer = ast2600_i2c_master_xfer,
+	.functionality = ast2600_i2c_functionality,
+};
+
+static const struct of_device_id ast2600_i2c_bus_of_table[] = {
+	{
+		.compatible = "aspeed,ast2600-i2cv2",
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, ast2600_i2c_bus_of_table);
+
+static int ast2600_i2c_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ast2600_i2c_bus *i2c_bus;
+	struct resource *res;
+	u32 global_ctrl;
+	int ret;
+
+	i2c_bus = devm_kzalloc(dev, sizeof(*i2c_bus), GFP_KERNEL);
+	if (!i2c_bus)
+		return -ENOMEM;
+
+	i2c_bus->reg_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(i2c_bus->reg_base))
+		return PTR_ERR(i2c_bus->reg_base);
+
+	i2c_bus->rst = devm_reset_control_get_shared(dev, NULL);
+	if (IS_ERR(i2c_bus->rst))
+		return dev_err_probe(dev, PTR_ERR(i2c_bus->rst), "Missing reset ctrl\n");
+
+	reset_control_deassert(i2c_bus->rst);
+
+	i2c_bus->global_regs = syscon_regmap_lookup_by_phandle(dev->of_node, "aspeed,global-regs");
+	if (IS_ERR(i2c_bus->global_regs))
+		return PTR_ERR(i2c_bus->global_regs);
+
+	regmap_read(i2c_bus->global_regs, AST2600_I2CG_CTRL, &global_ctrl);
+	if ((global_ctrl & AST2600_GLOBAL_INIT) != AST2600_GLOBAL_INIT) {
+		regmap_write(i2c_bus->global_regs, AST2600_I2CG_CTRL, AST2600_GLOBAL_INIT);
+		regmap_write(i2c_bus->global_regs, AST2600_I2CG_CLK_DIV_CTRL, I2CCG_DIV_CTRL);
+	}
+
+	i2c_bus->dev = dev;
+	i2c_bus->mode = BUFF_MODE;
+
+	if (device_property_read_bool(&pdev->dev, "aspeed,enable-dma"))
+		i2c_bus->mode = DMA_MODE;
+
+	if (i2c_bus->mode == BUFF_MODE) {
+		i2c_bus->buf_base = devm_platform_get_and_ioremap_resource(pdev, 1, &res);
+		if (!IS_ERR_OR_NULL(i2c_bus->buf_base))
+			i2c_bus->buf_size = resource_size(res) / 2;
+		else
+			i2c_bus->mode = BYTE_MODE;
+	}
+
+	/*
+	 * i2c timeout counter: use base clk4 1Mhz,
+	 * per unit: 1/(1000/4096) = 4096us
+	 */
+	ret = device_property_read_u32(dev, "i2c-scl-clk-low-timeout-us", &i2c_bus->timeout);
+	if (!ret)
+		i2c_bus->timeout /= 4096;
+
+	init_completion(&i2c_bus->cmd_complete);
+
+	i2c_bus->irq = platform_get_irq(pdev, 0);
+	if (i2c_bus->irq < 0)
+		return i2c_bus->irq;
+
+	platform_set_drvdata(pdev, i2c_bus);
+
+	i2c_bus->clk = devm_clk_get(i2c_bus->dev, NULL);
+	if (IS_ERR(i2c_bus->clk))
+		return dev_err_probe(i2c_bus->dev, PTR_ERR(i2c_bus->clk), "Can't get clock\n");
+
+	i2c_bus->apb_clk = clk_get_rate(i2c_bus->clk);
+
+	i2c_parse_fw_timings(i2c_bus->dev, &i2c_bus->timing_info, true);
+
+	/* Initialize the I2C adapter */
+	i2c_bus->adap.owner = THIS_MODULE;
+	i2c_bus->adap.algo = &i2c_ast2600_algorithm;
+	i2c_bus->adap.retries = 0;
+	i2c_bus->adap.dev.parent = i2c_bus->dev;
+	device_set_node(&i2c_bus->adap.dev, dev_fwnode(dev));
+	i2c_bus->adap.algo_data = i2c_bus;
+	strscpy(i2c_bus->adap.name, pdev->name, sizeof(i2c_bus->adap.name));
+	i2c_set_adapdata(&i2c_bus->adap, i2c_bus);
+
+	ast2600_i2c_init(i2c_bus);
+
+	ret = devm_request_irq(dev, i2c_bus->irq, ast2600_i2c_bus_irq, 0,
+			       dev_name(dev), i2c_bus);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Unable to request irq %d\n", i2c_bus->irq);
+
+	i2c_bus->alert_enable = device_property_read_bool(dev, "smbus-alert");
+	if (i2c_bus->alert_enable) {
+		i2c_bus->ara = i2c_new_smbus_alert_device(&i2c_bus->adap, &i2c_bus->alert_data);
+		if (!i2c_bus->ara)
+			dev_warn(dev, "Failed to register ARA client\n");
+
+		writel(AST2600_I2CM_PKT_DONE | AST2600_I2CM_BUS_RECOVER | AST2600_I2CM_SMBUS_ALT,
+		       i2c_bus->reg_base + AST2600_I2CM_IER);
+	} else {
+		i2c_bus->alert_enable = false;
+		/* Set interrupt generation of I2C master controller */
+		writel(AST2600_I2CM_PKT_DONE | AST2600_I2CM_BUS_RECOVER,
+		       i2c_bus->reg_base + AST2600_I2CM_IER);
+	}
+
+	ret = devm_i2c_add_adapter(dev, &i2c_bus->adap);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void ast2600_i2c_remove(struct platform_device *pdev)
+{
+	struct ast2600_i2c_bus *i2c_bus = platform_get_drvdata(pdev);
+
+	/* Disable everything. */
+	writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+	writel(0, i2c_bus->reg_base + AST2600_I2CM_IER);
+}
+
+static struct platform_driver ast2600_i2c_bus_driver = {
+	.probe = ast2600_i2c_probe,
+	.remove = ast2600_i2c_remove,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.of_match_table = ast2600_i2c_bus_of_table,
+	},
+};
+module_platform_driver(ast2600_i2c_bus_driver);
+
+MODULE_AUTHOR("Ryan Chen <ryan_chen@aspeedtech.com>");
+MODULE_DESCRIPTION("ASPEED AST2600 I2C Controller Driver");
+MODULE_LICENSE("GPL");