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[v3,0/4] i2c: thunderx: Marvell thunderx i2c changes

Message ID 20240206114349.32197-1-pmalgujar@marvell.com
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Series i2c: thunderx: Marvell thunderx i2c changes | expand

Message

Piyush Malgujar Feb. 6, 2024, 11:43 a.m. UTC
The changes are for Marvell OcteonTX2 SOC family:

- Handling clock divisor logic using subsytem ID
- Support for high speed mode
- Handle watchdog timeout
- Added ioclk support

Changes since V2:
- Respinning the series, no functional change
- Added Marvell member in MAINTAINERS file
- Added macro OTX2_REF_FREQ_DEFAULT for 100 MHz

Changes since V1:
- Addressed comments, added defines as required
- Removed unnecessary code
- Added a patch to support ioclk if sclk not present in ACPI table

Piyush Malgujar (1):
  i2c: thunderx: Adding ioclk support

Suneel Garapati (3):
  i2c: thunderx: Clock divisor logic changes
  i2c: thunderx: Add support for High speed mode
  i2c: octeon: Handle watchdog timeout

 MAINTAINERS                              |  1 +
 drivers/i2c/busses/i2c-octeon-core.c     | 96 ++++++++++++++++++------
 drivers/i2c/busses/i2c-octeon-core.h     | 27 +++++++
 drivers/i2c/busses/i2c-thunderx-pcidrv.c | 23 ++++--
 4 files changed, 117 insertions(+), 30 deletions(-)

Comments

Andi Shyti Feb. 8, 2024, 9:23 p.m. UTC | #1
Hi Piyush,

On Tue, Feb 06, 2024 at 03:43:46AM -0800, Piyush Malgujar wrote:
> From: Suneel Garapati <sgarapati@marvell.com>
> 
> Handle changes to clock divisor logic for OcteonTX2 SoC family using
> subsystem ID and using default reference clock source as 100MHz.
> 
> Signed-off-by: Suneel Garapati <sgarapati@marvell.com>
> Signed-off-by: Piyush Malgujar <pmalgujar@marvell.com>
> Acked-by: Andi Shyti <andi.shyti@kernel.org>
> ---
>  MAINTAINERS                              |  1 +
>  drivers/i2c/busses/i2c-octeon-core.c     | 29 ++++++++++++++++++++----
>  drivers/i2c/busses/i2c-octeon-core.h     | 17 ++++++++++++++
>  drivers/i2c/busses/i2c-thunderx-pcidrv.c |  7 ++++++
>  4 files changed, 50 insertions(+), 4 deletions(-)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 960512bec42885c0f1632a7c90851c3d32fbf20e..92b0a55c36e41cf54c7cbf52576d5424b591aa31 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4725,6 +4725,7 @@ F:	drivers/net/wireless/ath/carl9170/
>  
>  CAVIUM I2C DRIVER
>  M:	Robert Richter <rric@kernel.org>
> +M:	Suneel Garapati <sgarapati@marvell.com>

Suneel doesn't have much of a history here, though. Can I have an
ack from Robert?

In any case, can you please put this change outside from the
series as it would take a different path.

Thanks,
Andi
Andi Shyti Feb. 8, 2024, 9:35 p.m. UTC | #2
Hi Suneel and Piyush,

...

>  void octeon_i2c_set_clock(struct octeon_i2c *i2c)
>  {
>  	int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff;
> -	int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000;
> +	int mdiv_min = 2;

why is this int while all the other variables moved to be
"unsigned int"?

> +	/* starting value on search for lowest diff */
> +	const int huge_delta = INITIAL_DELTA_HZ;

this is not needed.

> +	/*
> +	 * Find divisors to produce target frequency, start with large delta
> +	 * to cover wider range of divisors, note thp = TCLK half period.
> +	 */
> +	unsigned int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = huge_delta;
> +
> +	if (octeon_i2c_is_otx2(to_pci_dev(i2c->dev))) {

you could save this in a boolean at the beginning and keep using
it.

> +		thp = 0x3;

as you are here, can we give a meaningful define to 0x18 and 0x3?

> +		mdiv_min = 0;
> +	}
>  
>  	for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) {
>  		/*
>  		 * An mdiv value of less than 2 seems to not work well
>  		 * with ds1337 RTCs, so we constrain it to larger values.
>  		 */
> -		for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) {
> +		for (mdiv_idx = 15; mdiv_idx >= mdiv_min && delta_hz != 0; mdiv_idx--) {
>  			/*
>  			 * For given ndiv and mdiv values check the
>  			 * two closest thp values.
>  			 */
>  			tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10;
>  			tclk *= (1 << ndiv_idx);
> -			thp_base = (i2c->sys_freq / (tclk * 2)) - 1;
> +			if (octeon_i2c_is_otx2(to_pci_dev(i2c->dev)))
> +				thp_base = (i2c->sys_freq / tclk) - 2;
> +			else
> +				thp_base = (i2c->sys_freq / (tclk * 2)) - 1;
>  
>  			for (inc = 0; inc <= 1; inc++) {
>  				thp_idx = thp_base + inc;
>  				if (thp_idx < 5 || thp_idx > 0xff)
>  					continue;
>  
> -				foscl = i2c->sys_freq / (2 * (thp_idx + 1));
> +				if (octeon_i2c_is_otx2(to_pci_dev(i2c->dev)))
> +					foscl = i2c->sys_freq / (thp_idx + 2);
> +				else
> +					foscl = i2c->sys_freq /
> +						(2 * (thp_idx + 1));

I need to trust you on this.

>  				foscl = foscl / (1 << ndiv_idx);
>  				foscl = foscl / (mdiv_idx + 1) / 10;
>  				diff = abs(foscl - i2c->twsi_freq);
> +				/* Use it if smaller diff from target */

can you please expand?

>  				if (diff < delta_hz) {
>  					delta_hz = diff;
>  					thp = thp_idx;
> diff --git a/drivers/i2c/busses/i2c-octeon-core.h b/drivers/i2c/busses/i2c-octeon-core.h
> index 9bb9f64fdda0392364638ecbaafe3fab5612baf6..694c24cecb7b144c1021549d1661b040c21bb998 100644
> --- a/drivers/i2c/busses/i2c-octeon-core.h
> +++ b/drivers/i2c/busses/i2c-octeon-core.h
> @@ -7,6 +7,7 @@
>  #include <linux/i2c-smbus.h>
>  #include <linux/io.h>
>  #include <linux/kernel.h>
> +#include <linux/pci.h>
>  
>  /* Controller command patterns */
>  #define SW_TWSI_V		BIT_ULL(63)	/* Valid bit */
> @@ -98,6 +99,8 @@ struct octeon_i2c_reg_offset {
>  #define TWSI_INT(x)	(x->roff.twsi_int)
>  #define SW_TWSI_EXT(x)	(x->roff.sw_twsi_ext)
>  
> +#define INITIAL_DELTA_HZ	1000000

This define doesn't need to be in the header, right? Can we move
it in the c file?

Andi
Andi Shyti Feb. 8, 2024, 9:41 p.m. UTC | #3
Hi,

On Tue, Feb 06, 2024 at 03:43:48AM -0800, Piyush Malgujar wrote:
> From: Suneel Garapati <sgarapati@marvell.com>
> 
> Status code 0xF0 refers to expiry of TWSI controller
> access watchdog and needs bus monitor reset using MODE
> register.

Please describe what you did, why you did it and how you did it.

Thanks,
Andi