diff mbox series

[v2,2/3] backlight: dwi_bl: Add Apple DWI backlight driver

Message ID 20241207130433.30351-3-towinchenmi@gmail.com
State Superseded
Headers show
Series Apple DWI backlight driver | expand

Commit Message

Nick Chan Dec. 7, 2024, 1:03 p.m. UTC
Add driver for backlight controllers attached via Apple DWI 2-wire
interface, which is found on some Apple iPhones, iPads and iPod touches
with a LCD display.

Signed-off-by: Nick Chan <towinchenmi@gmail.com>
---
 drivers/video/backlight/Kconfig  |  12 +++
 drivers/video/backlight/Makefile |   1 +
 drivers/video/backlight/dwi_bl.c | 124 +++++++++++++++++++++++++++++++
 3 files changed, 137 insertions(+)
 create mode 100644 drivers/video/backlight/dwi_bl.c

Comments

Krzysztof Kozlowski Dec. 9, 2024, 9:22 a.m. UTC | #1
On Sat, Dec 07, 2024 at 09:03:15PM +0800, Nick Chan wrote:
> Add driver for backlight controllers attached via Apple DWI 2-wire
> interface, which is found on some Apple iPhones, iPads and iPod touches
> with a LCD display.
> 
> Signed-off-by: Nick Chan <towinchenmi@gmail.com>
> ---
>  drivers/video/backlight/Kconfig  |  12 +++
>  drivers/video/backlight/Makefile |   1 +
>  drivers/video/backlight/dwi_bl.c | 124 +++++++++++++++++++++++++++++++
>  3 files changed, 137 insertions(+)
>  create mode 100644 drivers/video/backlight/dwi_bl.c
> 
> diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
> index 3614a5d29c71..e64cc3d51ac5 100644
> --- a/drivers/video/backlight/Kconfig
> +++ b/drivers/video/backlight/Kconfig
> @@ -166,6 +166,18 @@ config BACKLIGHT_EP93XX
>  	  To compile this driver as a module, choose M here: the module will
>  	  be called ep93xx_bl.
>  
> +config BACKLIGHT_APPLE_DWI
> +	tristate "Apple DWI 2-Wire Interface Backlight Driver"
> +	depends on ARCH_APPLE || COMPILE_TEST
> +	default y
> +	help
> +          Say Y to enable the backlight driver for backlight controllers
> +          attached via the Apple DWI 2-wire interface which is found in some
> +          Apple iPhones, iPads and iPod touches.

Mixed/messed indentation. Some spaces?

> +
> +	  To compile this driver as a module, choose M here: the module will
> +	  be called dwi_bl.
> +
>  config BACKLIGHT_IPAQ_MICRO
>  	tristate "iPAQ microcontroller backlight driver"
>  	depends on MFD_IPAQ_MICRO
> diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
> index 8fc98f760a8a..0a569d7f0210 100644
> --- a/drivers/video/backlight/Makefile
> +++ b/drivers/video/backlight/Makefile
> @@ -28,6 +28,7 @@ obj-$(CONFIG_BACKLIGHT_BD6107)		+= bd6107.o
>  obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE)	+= backlight.o
>  obj-$(CONFIG_BACKLIGHT_DA903X)		+= da903x_bl.o
>  obj-$(CONFIG_BACKLIGHT_DA9052)		+= da9052_bl.o
> +obj-$(CONFIG_BACKLIGHT_APPLE_DWI)	+= dwi_bl.o

Please do not introduce other sorting way - it is sorted by config name.
Which will also point you to apple_bl.o and need of explaining the
differences, e.g. why this cannot be one driver.


>  obj-$(CONFIG_BACKLIGHT_EP93XX)		+= ep93xx_bl.o
>  obj-$(CONFIG_BACKLIGHT_GPIO)		+= gpio_backlight.o
>  obj-$(CONFIG_BACKLIGHT_HP680)		+= hp680_bl.o
> diff --git a/drivers/video/backlight/dwi_bl.c b/drivers/video/backlight/dwi_bl.c
> new file mode 100644
> index 000000000000..d4bfd74b3129
> --- /dev/null
> +++ b/drivers/video/backlight/dwi_bl.c
> @@ -0,0 +1,124 @@
> +// SPDX-License-Identifier: GPL-2.0 OR MIT
> +/*
> + * Driver for backlight controllers attached via Apple DWI 2-wire interface
> + *
> + * Copyright (c) 2024 Nick Chan <towinchenmi@gmail.com>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/io.h>
> +#include <linux/backlight.h>
> +
> +#define DWI_BL_CTL			0x0
> +#define DWI_BL_CTL_SEND1		BIT(0)
> +#define DWI_BL_CTL_SEND2		BIT(4)
> +#define DWI_BL_CTL_SEND3		BIT(5)
> +#define DWI_BL_CTL_LE_DATA		BIT(6)
> +/* Only used on Apple A9 and later */
> +#define DWI_BL_CTL_SEND4		BIT(12)
> +
> +#define DWI_BL_CMD			0x4
> +#define DWI_BL_CMD_TYPE			GENMASK(31, 28)
> +#define DWI_BL_CMD_TYPE_SET_BRIGHTNESS	0xa
> +#define DWI_BL_CMD_DATA			GENMASK(10, 0)
> +
> +#define DWI_BL_CTL_SEND			(DWI_BL_CTL_SEND1 | \
> +					 DWI_BL_CTL_SEND2 | \
> +					 DWI_BL_CTL_SEND3 | \
> +					 DWI_BL_CTL_LE_DATA | \
> +					 DWI_BL_CTL_SEND4)
> +
> +#define DWI_BL_MAX_BRIGHTNESS		2047
> +
> +struct apple_dwi_bl {
> +	void __iomem *base;
> +};
> +
> +static int dwi_bl_update_status(struct backlight_device *bl)
> +{
> +	struct apple_dwi_bl *dwi_bl = bl_get_data(bl);
> +
> +	int brightness = backlight_get_brightness(bl);
> +
> +	u32 cmd = 0;
> +
> +	cmd |= FIELD_PREP(DWI_BL_CMD_DATA, brightness);
> +	cmd |= FIELD_PREP(DWI_BL_CMD_TYPE, DWI_BL_CMD_TYPE_SET_BRIGHTNESS);
> +
> +	writel(cmd, dwi_bl->base + DWI_BL_CMD);
> +	writel(DWI_BL_CTL_SEND, dwi_bl->base + DWI_BL_CTL);
> +
> +	return 0;
> +}
> +
> +static int dwi_bl_get_brightness(struct backlight_device *bl)
> +{
> +	struct apple_dwi_bl *dwi_bl = bl_get_data(bl);
> +
> +	u32 cmd = readl(dwi_bl->base + DWI_BL_CMD);
> +
> +	return FIELD_GET(DWI_BL_CMD_DATA, cmd);
> +}
> +
> +static const struct backlight_ops dwi_bl_ops = {
> +	.options = BL_CORE_SUSPENDRESUME,
> +	.get_brightness = dwi_bl_get_brightness,
> +	.update_status	= dwi_bl_update_status
> +};
> +
> +static int dwi_bl_probe(struct platform_device *dev)
> +{
> +	struct apple_dwi_bl *dwi_bl;
> +	struct backlight_device *bl;
> +	struct backlight_properties props;
> +	struct resource *res;
> +
> +	dwi_bl = devm_kzalloc(&dev->dev, sizeof(struct apple_dwi_bl), GFP_KERNEL);

sizeof(*)

> +	if (!dwi_bl)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
> +	if (!res)
> +		return -ENXIO;
> +
> +	dwi_bl->base = devm_ioremap_resource(&dev->dev, res);

Use helper for these two, devm_platform_get_and_ioremap_resource() or
similar.

Best regards,
Krzysztof
Nick Chan Dec. 9, 2024, 10:07 a.m. UTC | #2
Krzysztof Kozlowski 於 2024/12/9 下午5:22 寫道:
> On Sat, Dec 07, 2024 at 09:03:15PM +0800, Nick Chan wrote:
>> Add driver for backlight controllers attached via Apple DWI 2-wire
>> interface, which is found on some Apple iPhones, iPads and iPod touches
>> with a LCD display.
>>
>> Signed-off-by: Nick Chan <towinchenmi@gmail.com>
>> ---
>>  drivers/video/backlight/Kconfig  |  12 +++
>>  drivers/video/backlight/Makefile |   1 +
>>  drivers/video/backlight/dwi_bl.c | 124 +++++++++++++++++++++++++++++++
>>  3 files changed, 137 insertions(+)
>>  create mode 100644 drivers/video/backlight/dwi_bl.c
>>
>> diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
>> index 3614a5d29c71..e64cc3d51ac5 100644
>> --- a/drivers/video/backlight/Kconfig
>> +++ b/drivers/video/backlight/Kconfig
>> @@ -166,6 +166,18 @@ config BACKLIGHT_EP93XX
>>  	  To compile this driver as a module, choose M here: the module will
>>  	  be called ep93xx_bl.
>>  
>> +config BACKLIGHT_APPLE_DWI
>> +	tristate "Apple DWI 2-Wire Interface Backlight Driver"
>> +	depends on ARCH_APPLE || COMPILE_TEST
>> +	default y
>> +	help
>> +          Say Y to enable the backlight driver for backlight controllers
>> +          attached via the Apple DWI 2-wire interface which is found in some
>> +          Apple iPhones, iPads and iPod touches.
> 
> Mixed/messed indentation. Some spaces?
Ack. Will be fixed for v4.

> 
>> +
>> +	  To compile this driver as a module, choose M here: the module will
>> +	  be called dwi_bl.
>> +
>>  config BACKLIGHT_IPAQ_MICRO
>>  	tristate "iPAQ microcontroller backlight driver"
>>  	depends on MFD_IPAQ_MICRO
>> diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
>> index 8fc98f760a8a..0a569d7f0210 100644
>> --- a/drivers/video/backlight/Makefile
>> +++ b/drivers/video/backlight/Makefile
>> @@ -28,6 +28,7 @@ obj-$(CONFIG_BACKLIGHT_BD6107)		+= bd6107.o
>>  obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE)	+= backlight.o
>>  obj-$(CONFIG_BACKLIGHT_DA903X)		+= da903x_bl.o
>>  obj-$(CONFIG_BACKLIGHT_DA9052)		+= da9052_bl.o
>> +obj-$(CONFIG_BACKLIGHT_APPLE_DWI)	+= dwi_bl.o
> 
> Please do not introduce other sorting way - it is sorted by config name.
> Which will also point you to apple_bl.o and need of explaining the
> differences, e.g. why this cannot be one driver.

apple_bl is a driver backlight controllers on a PCI bus on Intel Macs,
which is
completely different from the Samsung-derived DWI block this driver
deals with.
This will be explained in the commit message for v4.

> 
> 
>>  obj-$(CONFIG_BACKLIGHT_EP93XX)		+= ep93xx_bl.o
>>  obj-$(CONFIG_BACKLIGHT_GPIO)		+= gpio_backlight.o
>>  obj-$(CONFIG_BACKLIGHT_HP680)		+= hp680_bl.o
>> diff --git a/drivers/video/backlight/dwi_bl.c b/drivers/video/backlight/dwi_bl.c
>> new file mode 100644
>> index 000000000000..d4bfd74b3129
>> --- /dev/null
>> +++ b/drivers/video/backlight/dwi_bl.c
>> @@ -0,0 +1,124 @@
>> +// SPDX-License-Identifier: GPL-2.0 OR MIT
>> +/*
>> + * Driver for backlight controllers attached via Apple DWI 2-wire interface
>> + *
>> + * Copyright (c) 2024 Nick Chan <towinchenmi@gmail.com>
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/io.h>
>> +#include <linux/backlight.h>
>> +
>> +#define DWI_BL_CTL			0x0
>> +#define DWI_BL_CTL_SEND1		BIT(0)
>> +#define DWI_BL_CTL_SEND2		BIT(4)
>> +#define DWI_BL_CTL_SEND3		BIT(5)
>> +#define DWI_BL_CTL_LE_DATA		BIT(6)
>> +/* Only used on Apple A9 and later */
>> +#define DWI_BL_CTL_SEND4		BIT(12)
>> +
>> +#define DWI_BL_CMD			0x4
>> +#define DWI_BL_CMD_TYPE			GENMASK(31, 28)
>> +#define DWI_BL_CMD_TYPE_SET_BRIGHTNESS	0xa
>> +#define DWI_BL_CMD_DATA			GENMASK(10, 0)
>> +
>> +#define DWI_BL_CTL_SEND			(DWI_BL_CTL_SEND1 | \
>> +					 DWI_BL_CTL_SEND2 | \
>> +					 DWI_BL_CTL_SEND3 | \
>> +					 DWI_BL_CTL_LE_DATA | \
>> +					 DWI_BL_CTL_SEND4)
>> +
>> +#define DWI_BL_MAX_BRIGHTNESS		2047
>> +
>> +struct apple_dwi_bl {
>> +	void __iomem *base;
>> +};
>> +
>> +static int dwi_bl_update_status(struct backlight_device *bl)
>> +{
>> +	struct apple_dwi_bl *dwi_bl = bl_get_data(bl);
>> +
>> +	int brightness = backlight_get_brightness(bl);
>> +
>> +	u32 cmd = 0;
>> +
>> +	cmd |= FIELD_PREP(DWI_BL_CMD_DATA, brightness);
>> +	cmd |= FIELD_PREP(DWI_BL_CMD_TYPE, DWI_BL_CMD_TYPE_SET_BRIGHTNESS);
>> +
>> +	writel(cmd, dwi_bl->base + DWI_BL_CMD);
>> +	writel(DWI_BL_CTL_SEND, dwi_bl->base + DWI_BL_CTL);
>> +
>> +	return 0;
>> +}
>> +
>> +static int dwi_bl_get_brightness(struct backlight_device *bl)
>> +{
>> +	struct apple_dwi_bl *dwi_bl = bl_get_data(bl);
>> +
>> +	u32 cmd = readl(dwi_bl->base + DWI_BL_CMD);
>> +
>> +	return FIELD_GET(DWI_BL_CMD_DATA, cmd);
>> +}
>> +
>> +static const struct backlight_ops dwi_bl_ops = {
>> +	.options = BL_CORE_SUSPENDRESUME,
>> +	.get_brightness = dwi_bl_get_brightness,
>> +	.update_status	= dwi_bl_update_status
>> +};
>> +
>> +static int dwi_bl_probe(struct platform_device *dev)
>> +{
>> +	struct apple_dwi_bl *dwi_bl;
>> +	struct backlight_device *bl;
>> +	struct backlight_properties props;
>> +	struct resource *res;
>> +
>> +	dwi_bl = devm_kzalloc(&dev->dev, sizeof(struct apple_dwi_bl), GFP_KERNEL);
> 
> sizeof(*)
> 
>> +	if (!dwi_bl)
>> +		return -ENOMEM;
>> +
>> +	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
>> +	if (!res)
>> +		return -ENXIO;
>> +
>> +	dwi_bl->base = devm_ioremap_resource(&dev->dev, res);
> 
> Use helper for these two, devm_platform_get_and_ioremap_resource() or
> similar.
Ack. Will be fixed for v4.

> 
> Best regards,
> Krzysztof
> 

Nick Chan
Nick Chan Dec. 9, 2024, 10:22 a.m. UTC | #3
Krzysztof Kozlowski 於 2024/12/9 下午5:22 寫道:
>> diff --git a/drivers/video/backlight/dwi_bl.c b/drivers/video/backlight/dwi_bl.c
>> new file mode 100644
>> index 000000000000..d4bfd74b3129
>> --- /dev/null
>> +++ b/drivers/video/backlight/dwi_bl.c
>> @@ -0,0 +1,124 @@
[...]
>> +
>> +	dwi_bl = devm_kzalloc(&dev->dev, sizeof(struct apple_dwi_bl), GFP_KERNEL);
> 
> sizeof(*)

Ack this change as well for v4.

> 
>> +	if (!dwi_bl)
>> +		return -ENOMEM;
[...]

Nick Chan
diff mbox series

Patch

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 3614a5d29c71..e64cc3d51ac5 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -166,6 +166,18 @@  config BACKLIGHT_EP93XX
 	  To compile this driver as a module, choose M here: the module will
 	  be called ep93xx_bl.
 
+config BACKLIGHT_APPLE_DWI
+	tristate "Apple DWI 2-Wire Interface Backlight Driver"
+	depends on ARCH_APPLE || COMPILE_TEST
+	default y
+	help
+          Say Y to enable the backlight driver for backlight controllers
+          attached via the Apple DWI 2-wire interface which is found in some
+          Apple iPhones, iPads and iPod touches.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called dwi_bl.
+
 config BACKLIGHT_IPAQ_MICRO
 	tristate "iPAQ microcontroller backlight driver"
 	depends on MFD_IPAQ_MICRO
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 8fc98f760a8a..0a569d7f0210 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -28,6 +28,7 @@  obj-$(CONFIG_BACKLIGHT_BD6107)		+= bd6107.o
 obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE)	+= backlight.o
 obj-$(CONFIG_BACKLIGHT_DA903X)		+= da903x_bl.o
 obj-$(CONFIG_BACKLIGHT_DA9052)		+= da9052_bl.o
+obj-$(CONFIG_BACKLIGHT_APPLE_DWI)	+= dwi_bl.o
 obj-$(CONFIG_BACKLIGHT_EP93XX)		+= ep93xx_bl.o
 obj-$(CONFIG_BACKLIGHT_GPIO)		+= gpio_backlight.o
 obj-$(CONFIG_BACKLIGHT_HP680)		+= hp680_bl.o
diff --git a/drivers/video/backlight/dwi_bl.c b/drivers/video/backlight/dwi_bl.c
new file mode 100644
index 000000000000..d4bfd74b3129
--- /dev/null
+++ b/drivers/video/backlight/dwi_bl.c
@@ -0,0 +1,124 @@ 
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Driver for backlight controllers attached via Apple DWI 2-wire interface
+ *
+ * Copyright (c) 2024 Nick Chan <towinchenmi@gmail.com>
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/backlight.h>
+
+#define DWI_BL_CTL			0x0
+#define DWI_BL_CTL_SEND1		BIT(0)
+#define DWI_BL_CTL_SEND2		BIT(4)
+#define DWI_BL_CTL_SEND3		BIT(5)
+#define DWI_BL_CTL_LE_DATA		BIT(6)
+/* Only used on Apple A9 and later */
+#define DWI_BL_CTL_SEND4		BIT(12)
+
+#define DWI_BL_CMD			0x4
+#define DWI_BL_CMD_TYPE			GENMASK(31, 28)
+#define DWI_BL_CMD_TYPE_SET_BRIGHTNESS	0xa
+#define DWI_BL_CMD_DATA			GENMASK(10, 0)
+
+#define DWI_BL_CTL_SEND			(DWI_BL_CTL_SEND1 | \
+					 DWI_BL_CTL_SEND2 | \
+					 DWI_BL_CTL_SEND3 | \
+					 DWI_BL_CTL_LE_DATA | \
+					 DWI_BL_CTL_SEND4)
+
+#define DWI_BL_MAX_BRIGHTNESS		2047
+
+struct apple_dwi_bl {
+	void __iomem *base;
+};
+
+static int dwi_bl_update_status(struct backlight_device *bl)
+{
+	struct apple_dwi_bl *dwi_bl = bl_get_data(bl);
+
+	int brightness = backlight_get_brightness(bl);
+
+	u32 cmd = 0;
+
+	cmd |= FIELD_PREP(DWI_BL_CMD_DATA, brightness);
+	cmd |= FIELD_PREP(DWI_BL_CMD_TYPE, DWI_BL_CMD_TYPE_SET_BRIGHTNESS);
+
+	writel(cmd, dwi_bl->base + DWI_BL_CMD);
+	writel(DWI_BL_CTL_SEND, dwi_bl->base + DWI_BL_CTL);
+
+	return 0;
+}
+
+static int dwi_bl_get_brightness(struct backlight_device *bl)
+{
+	struct apple_dwi_bl *dwi_bl = bl_get_data(bl);
+
+	u32 cmd = readl(dwi_bl->base + DWI_BL_CMD);
+
+	return FIELD_GET(DWI_BL_CMD_DATA, cmd);
+}
+
+static const struct backlight_ops dwi_bl_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.get_brightness = dwi_bl_get_brightness,
+	.update_status	= dwi_bl_update_status
+};
+
+static int dwi_bl_probe(struct platform_device *dev)
+{
+	struct apple_dwi_bl *dwi_bl;
+	struct backlight_device *bl;
+	struct backlight_properties props;
+	struct resource *res;
+
+	dwi_bl = devm_kzalloc(&dev->dev, sizeof(struct apple_dwi_bl), GFP_KERNEL);
+	if (!dwi_bl)
+		return -ENOMEM;
+
+	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENXIO;
+
+	dwi_bl->base = devm_ioremap_resource(&dev->dev, res);
+	if (IS_ERR(dwi_bl->base))
+		return PTR_ERR(dwi_bl->base);
+
+	memset(&props, 0, sizeof(struct backlight_properties));
+	props.type = BACKLIGHT_RAW;
+	props.max_brightness = DWI_BL_MAX_BRIGHTNESS;
+
+	bl = devm_backlight_device_register(&dev->dev, dev->name, &dev->dev,
+					dwi_bl, &dwi_bl_ops, &props);
+	if (IS_ERR(bl))
+		return PTR_ERR(bl);
+
+	platform_set_drvdata(dev, dwi_bl);
+
+	bl->props.brightness = dwi_bl_get_brightness(bl);
+
+	return 0;
+}
+
+static const struct of_device_id dwi_bl_of_match[] = {
+	{ .compatible = "apple,dwi-bl" },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, dwi_bl_of_match);
+
+static struct platform_driver dwi_bl_driver = {
+	.driver		= {
+		.name	= "dwi-bl",
+		.of_match_table = dwi_bl_of_match
+	},
+	.probe		= dwi_bl_probe,
+};
+
+module_platform_driver(dwi_bl_driver);
+
+MODULE_DESCRIPTION("Apple DWI Backlight Driver");
+MODULE_AUTHOR("Nick Chan <towinchenmi@gmail.com>");
+MODULE_LICENSE("Dual MIT/GPL");