| Message ID | 20241211113512.19009-3-towinchenmi@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Apple DWI backlight driver | expand |
On Wed, Dec 11, 2024 at 07:34:38PM +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. > > Although there is an existing apple_bl driver, it is for backlight > controllers on Intel Macs attached via PCI, which is completely different > from the Samsung-derived DWI block. > > Signed-off-by: Nick Chan <towinchenmi@gmail.com> > --- > drivers/video/backlight/Kconfig | 12 +++ > drivers/video/backlight/Makefile | 1 + > drivers/video/backlight/dwi_bl.c | 122 +++++++++++++++++++++++++++++++ I'd rather this was called apple_dwi_bl.c to match that config options, etc. > diff --git a/drivers/video/backlight/dwi_bl.c b/drivers/video/backlight/dwi_bl.c > new file mode 100644 > index 000000000000..59e5cad0fbd8 > --- /dev/null > +++ b/drivers/video/backlight/dwi_bl.c > @@ -0,0 +1,122 @@ > +// 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/backlight.h> > +#include <linux/bitfield.h> > +#include <linux/device.h> > +#include <linux/io.h> > +#include <linux/module.h> > +#include <linux/platform_device.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(*dwi_bl), GFP_KERNEL); > + if (!dwi_bl) > + return -ENOMEM; > + > + dwi_bl->base = devm_platform_get_and_ioremap_resource(dev, 0, &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; There should be something to indicate whether the backlight controls are linear or logarithmic here. > +static struct platform_driver dwi_bl_driver = { > + .driver = { > + .name = "dwi-bl", Again, I'd rather see apple here too (although, to be clear, I'm perfectly happy with all the static functions and variables being prefixed only with dwi_bl). Daniel.
On Thu, Jan 09, 2025 at 11:52:56PM +0800, Nick Chan wrote: > > Daniel Thompson 於 2025/1/8 下晝6:52 寫道: > > On Wed, Dec 11, 2024 at 07:34:38PM +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. > >> > >> Although there is an existing apple_bl driver, it is for backlight > >> controllers on Intel Macs attached via PCI, which is completely different > >> from the Samsung-derived DWI block. > >> > >> Signed-off-by: Nick Chan <towinchenmi@gmail.com> > >> --- > >> drivers/video/backlight/Kconfig | 12 +++ > >> drivers/video/backlight/Makefile | 1 + > >> drivers/video/backlight/dwi_bl.c | 122 +++++++++++++++++++++++++++++++ > > I'd rather this was called apple_dwi_bl.c to match that config options, > > etc. > Still trying to determine the type of the backlight control, I think > it is linear however and I will send a new version when I am more > certain. If you've got an physicalinstance of the backlight then you can get a general idea by comparing levels: 512, 1024, 1536 and 2047. A linear backlight will feel make the gaps feel uneven (e.g. the difference between 1536 and 2047 will look very different to the difference difference between 512 and 1024). A logarithmic backligt will make the perceived brightness intervals between the above all feel pretty similar. Daniel.
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index 3614a5d29c71..debb1326df63 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -290,6 +290,18 @@ config BACKLIGHT_APPLE If you have an Intel-based Apple say Y to enable a driver for its backlight. +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_QCOM_WLED tristate "Qualcomm PMIC WLED Driver" select REGMAP diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile index 8fc98f760a8a..45cc80d9ae22 100644 --- a/drivers/video/backlight/Makefile +++ b/drivers/video/backlight/Makefile @@ -23,6 +23,7 @@ obj-$(CONFIG_BACKLIGHT_ADP5520) += adp5520_bl.o obj-$(CONFIG_BACKLIGHT_ADP8860) += adp8860_bl.o obj-$(CONFIG_BACKLIGHT_ADP8870) += adp8870_bl.o obj-$(CONFIG_BACKLIGHT_APPLE) += apple_bl.o +obj-$(CONFIG_BACKLIGHT_APPLE_DWI) += dwi_bl.o obj-$(CONFIG_BACKLIGHT_AS3711) += as3711_bl.o obj-$(CONFIG_BACKLIGHT_BD6107) += bd6107.o obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE) += backlight.o diff --git a/drivers/video/backlight/dwi_bl.c b/drivers/video/backlight/dwi_bl.c new file mode 100644 index 000000000000..59e5cad0fbd8 --- /dev/null +++ b/drivers/video/backlight/dwi_bl.c @@ -0,0 +1,122 @@ +// 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/backlight.h> +#include <linux/bitfield.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/platform_device.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(*dwi_bl), GFP_KERNEL); + if (!dwi_bl) + return -ENOMEM; + + dwi_bl->base = devm_platform_get_and_ioremap_resource(dev, 0, &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");
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. Although there is an existing apple_bl driver, it is for backlight controllers on Intel Macs attached via PCI, which is completely different from the Samsung-derived DWI block. Signed-off-by: Nick Chan <towinchenmi@gmail.com> --- drivers/video/backlight/Kconfig | 12 +++ drivers/video/backlight/Makefile | 1 + drivers/video/backlight/dwi_bl.c | 122 +++++++++++++++++++++++++++++++ 3 files changed, 135 insertions(+) create mode 100644 drivers/video/backlight/dwi_bl.c