[PATCHv2 0/2] Apple Magic Keyboard Backlight

[PATCHv2 0/2] Apple Magic Keyboard Backlight

[Orlando Chamberlain]

This patchseries adds support for the internal keyboard backlight of
Macs with Apple's "Magic" keyboard (MacBookPro16,* and MacBookAir9,1),
and also documents what names should be used for keyboard backlight
leds in Documentation/leds/well-known-leds.txt.

A previous version of this patch was sent alongside some other drivers
here[1] but for v2 I'm submitting it separately to make upstreaming
easier.

v1->v2:
- drop unneeded remove function
- combine set functions
- add missing header inclusions
- avoid char as argument in favour of u8
- handful of style/formatting fixes
- use standard led name ":white:kbd_backlight"
- rename USAGE_MAGIC_BL to HID_USAGE_MAGIC_BL
- New patch documenting preferred keyboard backlight names

[1]: https://lore.kernel.org/linux-input/7D70F1FE-7F54-4D0A-8922-5466AA2AD364@live.com/

Orlando Chamberlain (2):
  Documentation: leds: standardise keyboard backlight led names
  HID: apple-magic-backlight: Add driver for keyboard backlight on
    internal Magic Keyboards

 Documentation/leds/well-known-leds.txt |   8 ++
 MAINTAINERS                            |   6 ++
 drivers/hid/Kconfig                    |  13 +++
 drivers/hid/Makefile                   |   1 +
 drivers/hid/apple-magic-backlight.c    | 125 +++++++++++++++++++++++++
 5 files changed, 153 insertions(+)
 create mode 100644 drivers/hid/apple-magic-backlight.c

-- 
2.39.1

[PATCH 1/2] Documentation: leds: standardise keyboard backlight led names

[Orlando Chamberlain]

Advice use of either "input*:*:kbd_backlight" or ":*:kbd_backlight". We
don't want drivers using vendor or product name (e.g. "smc", "apple",
"asus") as this information is available from sysfs anyway, and it made the
folder names inconsistent.

Signed-off-by: Orlando Chamberlain <orlandoch.dev@gmail.com>
---
 Documentation/leds/well-known-leds.txt | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/leds/well-known-leds.txt b/Documentation/leds/well-known-leds.txt
index 2160382c86be..4e5429fce4d8 100644
--- a/Documentation/leds/well-known-leds.txt
+++ b/Documentation/leds/well-known-leds.txt
@@ -44,6 +44,14 @@ Legacy: "lp5523:kb{1,2,3,4,5,6}" (Nokia N900)
 
 Frontlight/backlight of main keyboard.
 
+Good: ":*:kbd_backlight"
+Good: "input*:*:kbd_backlight"
+Legacy: "*:*:kbd_backlight"
+
+Many drivers have the vendor or product name as the first field of the led name,
+this makes names inconsistent and is redundant as that information is already in
+sysfs.
+
 Legacy: "button-backlight" (Motorola Droid 4)
 
 Some phones have touch buttons below screen; it is different from main
-- 
2.39.1

[PATCH 2/2] HID: apple-magic-backlight: Add driver for keyboard backlight on internal Magic Keyboards

[Orlando Chamberlain]

This driver adds support for the keyboard backlight on Intel T2 Macs
with internal Magic Keyboards (MacBookPro16,x and MacBookAir9,1)

Signed-off-by: Orlando Chamberlain <orlandoch.dev@gmail.com>
Co-developed-by: Kerem Karabay <kekrby@gmail.com>
Signed-off-by: Kerem Karabay <kekrby@gmail.com>
---
 MAINTAINERS                         |   6 ++
 drivers/hid/Kconfig                 |  13 +++
 drivers/hid/Makefile                |   1 +
 drivers/hid/apple-magic-backlight.c | 125 ++++++++++++++++++++++++++++
 4 files changed, 145 insertions(+)
 create mode 100644 drivers/hid/apple-magic-backlight.c

diff --git a/MAINTAINERS b/MAINTAINERS
index fb1471cb5ed3..3319f0c3ed1e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9201,6 +9201,12 @@ F:	include/linux/pm.h
 F:	include/linux/suspend.h
 F:	kernel/power/
 
+HID APPLE MAGIC BACKLIGHT DRIVER
+M:	Orlando Chamberlain <orlandoch.dev@gmail.com>
+L:	linux-input@vger.kernel.org
+S:	Maintained
+F:	drivers/hid/apple-magic-backlight.c
+
 HID CORE LAYER
 M:	Jiri Kosina <jikos@kernel.org>
 M:	Benjamin Tissoires <benjamin.tissoires@redhat.com>
diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index e2a5d30c8895..f4702d32ce2f 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -130,6 +130,19 @@ config HID_APPLE
 	Say Y here if you want support for keyboards of	Apple iBooks, PowerBooks,
 	MacBooks, MacBook Pros and Apple Aluminum.
 
+config HID_APPLE_MAGIC_BACKLIGHT
+	tristate "Apple Magic Keyboard Backlight"
+	depends on USB_HID
+	depends on LEDS_CLASS
+	depends on NEW_LEDS
+	help
+	Say Y here if you want support for the keyboard backlight on Macs with
+	the magic keyboard (MacBookPro16,x and MacBookAir9,1). Note that this
+	driver is not for external magic keyboards.
+
+	To compile this driver as a module, choose M here: the
+	module will be called apple-magic-backlight.
+
 config HID_APPLEIR
 	tristate "Apple infrared receiver"
 	depends on (USB_HID)
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index e8014c1a2f8b..5cbfe85dd31b 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_HID_ACCUTOUCH)	+= hid-accutouch.o
 obj-$(CONFIG_HID_ALPS)		+= hid-alps.o
 obj-$(CONFIG_HID_ACRUX)		+= hid-axff.o
 obj-$(CONFIG_HID_APPLE)		+= hid-apple.o
+obj-$(CONFIG_HID_APPLE_MAGIC_BACKLIGHT)	+= apple-magic-backlight.o
 obj-$(CONFIG_HID_APPLEIR)	+= hid-appleir.o
 obj-$(CONFIG_HID_CREATIVE_SB0540)	+= hid-creative-sb0540.o
 obj-$(CONFIG_HID_ASUS)		+= hid-asus.o
diff --git a/drivers/hid/apple-magic-backlight.c b/drivers/hid/apple-magic-backlight.c
new file mode 100644
index 000000000000..ed5bcf5bb599
--- /dev/null
+++ b/drivers/hid/apple-magic-backlight.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Apple Magic Keyboard Backlight Driver
+ *
+ * For Intel Macs with internal Magic Keyboard (MacBookPro16,1-4 and MacBookAir9,1)
+ *
+ * Copyright (c) 2022 Kerem Karabay <kekrby@gmail.com>
+ * Copyright (c) 2023 Orlando Chamberlain <orlandoch.dev@gmail.com>
+ */
+
+#include <linux/hid.h>
+#include <linux/usb.h>
+#include <linux/leds.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <dt-bindings/leds/common.h>
+
+#include "hid-ids.h"
+
+#define HID_USAGE_MAGIC_BL	0xff00000f
+
+#define APPLE_MAGIC_REPORT_ID_POWER 3
+#define APPLE_MAGIC_REPORT_ID_BRIGHTNESS 1
+
+struct apple_magic_backlight {
+	struct led_classdev cdev;
+	struct hid_device *hdev;
+	struct hid_report *brightness;
+	struct hid_report *power;
+};
+
+static void apple_magic_backlight_report_set(struct hid_report *rep, u16 value, u8 rate)
+{
+	rep->field[0]->value[0] = value;
+	rep->field[1]->value[0] = 0x5e; /* Mimic Windows */
+	rep->field[1]->value[0] |= rate << 8;
+
+	hid_hw_request(rep->device, rep, HID_REQ_SET_REPORT);
+}
+
+static void apple_magic_backlight_set(struct apple_magic_backlight *backlight,
+				     int brightness, char rate)
+{
+	apple_magic_backlight_report_set(backlight->power, brightness ? 1 : 0, rate);
+	if (brightness)
+		apple_magic_backlight_report_set(backlight->brightness, brightness, rate);
+}
+
+static int apple_magic_backlight_led_set(struct led_classdev *led_cdev,
+					 enum led_brightness brightness)
+{
+	struct apple_magic_backlight *backlight = container_of(led_cdev,
+			struct apple_magic_backlight, cdev);
+
+	apple_magic_backlight_set(backlight, brightness, 1);
+	return 0;
+}
+
+static int apple_magic_backlight_probe(struct hid_device *hdev,
+				       const struct hid_device_id *id)
+{
+	struct apple_magic_backlight *backlight;
+	int rc;
+
+	rc = hid_parse(hdev);
+	if (rc)
+		return rc;
+
+	/*
+	 * Ensure this usb endpoint is for the keyboard backlight, not touchbar
+	 * backlight.
+	 */
+	if (!(hdev->collection && hdev->collection[0].usage == HID_USAGE_MAGIC_BL))
+		return -ENODEV;
+
+	backlight = devm_kzalloc(&hdev->dev, sizeof(*backlight), GFP_KERNEL);
+	if (!backlight)
+		return -ENOMEM;
+
+	hid_set_drvdata(hdev, backlight);
+
+	rc = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (rc)
+		return rc;
+
+	backlight->brightness = hid_register_report(hdev, HID_FEATURE_REPORT,
+			APPLE_MAGIC_REPORT_ID_BRIGHTNESS, 0);
+	backlight->power = hid_register_report(hdev, HID_FEATURE_REPORT,
+			APPLE_MAGIC_REPORT_ID_POWER, 0);
+
+	if (!backlight->brightness || !backlight->power) {
+		rc = -ENODEV;
+		goto hw_stop;
+	}
+
+	backlight->hdev = hdev;
+	backlight->cdev.name = ":white:" LED_FUNCTION_KBD_BACKLIGHT;
+	backlight->cdev.max_brightness = backlight->brightness->field[0]->logical_maximum;
+	backlight->cdev.brightness_set_blocking = apple_magic_backlight_led_set;
+
+	apple_magic_backlight_set(backlight, 0, 0);
+
+	return devm_led_classdev_register(&hdev->dev, &backlight->cdev);
+
+hw_stop:
+	hid_hw_stop(hdev);
+	return rc;
+}
+
+static const struct hid_device_id apple_magic_backlight_hid_ids[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_BACKLIGHT) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, apple_magic_backlight_hid_ids);
+
+static struct hid_driver apple_magic_backlight_hid_driver = {
+	.name = "apple-magic-backlight",
+	.id_table = apple_magic_backlight_hid_ids,
+	.probe = apple_magic_backlight_probe,
+};
+module_hid_driver(apple_magic_backlight_hid_driver);
+
+MODULE_DESCRIPTION("MacBook Magic Keyboard Backlight");
+MODULE_AUTHOR("Orlando Chamberlain <orlandoch.dev@gmail.com>");
+MODULE_LICENSE("GPL");
-- 
2.39.1

Re: [PATCH 2/2] HID: apple-magic-backlight: Add driver for keyboard backlight on internal Magic Keyboards

[Thomas Weißschuh]

On Thu, Feb 16, 2023 at 03:12:28PM +1100, Orlando Chamberlain wrote:
> This driver adds support for the keyboard backlight on Intel T2 Macs
> with internal Magic Keyboards (MacBookPro16,x and MacBookAir9,1)
> 
> Signed-off-by: Orlando Chamberlain <orlandoch.dev@gmail.com>
> Co-developed-by: Kerem Karabay <kekrby@gmail.com>
> Signed-off-by: Kerem Karabay <kekrby@gmail.com>

The last Signed-off-by should be yours.
See Documentation/process/submitting-patches.rst.

> ---
>  MAINTAINERS                         |   6 ++
>  drivers/hid/Kconfig                 |  13 +++
>  drivers/hid/Makefile                |   1 +
>  drivers/hid/apple-magic-backlight.c | 125 ++++++++++++++++++++++++++++
>  4 files changed, 145 insertions(+)
>  create mode 100644 drivers/hid/apple-magic-backlight.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fb1471cb5ed3..3319f0c3ed1e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9201,6 +9201,12 @@ F:	include/linux/pm.h
>  F:	include/linux/suspend.h
>  F:	kernel/power/
>  
> +HID APPLE MAGIC BACKLIGHT DRIVER
> +M:	Orlando Chamberlain <orlandoch.dev@gmail.com>
> +L:	linux-input@vger.kernel.org
> +S:	Maintained
> +F:	drivers/hid/apple-magic-backlight.c
> +
>  HID CORE LAYER
>  M:	Jiri Kosina <jikos@kernel.org>
>  M:	Benjamin Tissoires <benjamin.tissoires@redhat.com>
> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> index e2a5d30c8895..f4702d32ce2f 100644
> --- a/drivers/hid/Kconfig
> +++ b/drivers/hid/Kconfig
> @@ -130,6 +130,19 @@ config HID_APPLE
>  	Say Y here if you want support for keyboards of	Apple iBooks, PowerBooks,
>  	MacBooks, MacBook Pros and Apple Aluminum.
>  
> +config HID_APPLE_MAGIC_BACKLIGHT
> +	tristate "Apple Magic Keyboard Backlight"
> +	depends on USB_HID
> +	depends on LEDS_CLASS
> +	depends on NEW_LEDS
> +	help
> +	Say Y here if you want support for the keyboard backlight on Macs with
> +	the magic keyboard (MacBookPro16,x and MacBookAir9,1). Note that this
> +	driver is not for external magic keyboards.
> +
> +	To compile this driver as a module, choose M here: the
> +	module will be called apple-magic-backlight.
> +
>  config HID_APPLEIR
>  	tristate "Apple infrared receiver"
>  	depends on (USB_HID)
> diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
> index e8014c1a2f8b..5cbfe85dd31b 100644
> --- a/drivers/hid/Makefile
> +++ b/drivers/hid/Makefile
> @@ -26,6 +26,7 @@ obj-$(CONFIG_HID_ACCUTOUCH)	+= hid-accutouch.o
>  obj-$(CONFIG_HID_ALPS)		+= hid-alps.o
>  obj-$(CONFIG_HID_ACRUX)		+= hid-axff.o
>  obj-$(CONFIG_HID_APPLE)		+= hid-apple.o
> +obj-$(CONFIG_HID_APPLE_MAGIC_BACKLIGHT)	+= apple-magic-backlight.o
>  obj-$(CONFIG_HID_APPLEIR)	+= hid-appleir.o
>  obj-$(CONFIG_HID_CREATIVE_SB0540)	+= hid-creative-sb0540.o
>  obj-$(CONFIG_HID_ASUS)		+= hid-asus.o
> diff --git a/drivers/hid/apple-magic-backlight.c b/drivers/hid/apple-magic-backlight.c
> new file mode 100644
> index 000000000000..ed5bcf5bb599
> --- /dev/null
> +++ b/drivers/hid/apple-magic-backlight.c
> @@ -0,0 +1,125 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Apple Magic Keyboard Backlight Driver
> + *
> + * For Intel Macs with internal Magic Keyboard (MacBookPro16,1-4 and MacBookAir9,1)
> + *
> + * Copyright (c) 2022 Kerem Karabay <kekrby@gmail.com>
> + * Copyright (c) 2023 Orlando Chamberlain <orlandoch.dev@gmail.com>
> + */
> +
> +#include <linux/hid.h>
> +#include <linux/usb.h>

No need for linux/usb.h.

> +#include <linux/leds.h>
> +#include <linux/device.h>
> +#include <linux/errno.h>
> +#include <dt-bindings/leds/common.h>
> +
> +#include "hid-ids.h"
> +
> +#define HID_USAGE_MAGIC_BL	0xff00000f
> +
> +#define APPLE_MAGIC_REPORT_ID_POWER 3
> +#define APPLE_MAGIC_REPORT_ID_BRIGHTNESS 1
> +
> +struct apple_magic_backlight {
> +	struct led_classdev cdev;
> +	struct hid_device *hdev;
> +	struct hid_report *brightness;
> +	struct hid_report *power;
> +};
> +
> +static void apple_magic_backlight_report_set(struct hid_report *rep, u16 value, u8 rate)
> +{

Could "value" be a s32? "logical_maximum" from the field is a s32,
so there is no risk of truncation.

> +	rep->field[0]->value[0] = value;
> +	rep->field[1]->value[0] = 0x5e; /* Mimic Windows */
> +	rep->field[1]->value[0] |= rate << 8;
> +
> +	hid_hw_request(rep->device, rep, HID_REQ_SET_REPORT);
> +}
> +
> +static void apple_magic_backlight_set(struct apple_magic_backlight *backlight,
> +				     int brightness, char rate)
> +{
> +	apple_magic_backlight_report_set(backlight->power, brightness ? 1 : 0, rate);
> +	if (brightness)
> +		apple_magic_backlight_report_set(backlight->brightness, brightness, rate);
> +}
> +
> +static int apple_magic_backlight_led_set(struct led_classdev *led_cdev,
> +					 enum led_brightness brightness)
> +{
> +	struct apple_magic_backlight *backlight = container_of(led_cdev,
> +			struct apple_magic_backlight, cdev);
> +
> +	apple_magic_backlight_set(backlight, brightness, 1);
> +	return 0;
> +}
> +
> +static int apple_magic_backlight_probe(struct hid_device *hdev,
> +				       const struct hid_device_id *id)
> +{
> +	struct apple_magic_backlight *backlight;
> +	int rc;
> +
> +	rc = hid_parse(hdev);
> +	if (rc)
> +		return rc;
> +
> +	/*
> +	 * Ensure this usb endpoint is for the keyboard backlight, not touchbar
> +	 * backlight.
> +	 */
> +	if (!(hdev->collection && hdev->collection[0].usage == HID_USAGE_MAGIC_BL))
> +		return -ENODEV;

I don't think hdev->collection can ever be NULL.

Also personally I would prefer this:

!hdev->collection || hdev->collection[0].usage != HID_USAGE_MAGIC_BL

Like it is done with the reports below.

> +
> +	backlight = devm_kzalloc(&hdev->dev, sizeof(*backlight), GFP_KERNEL);
> +	if (!backlight)
> +		return -ENOMEM;
> +
> +	hid_set_drvdata(hdev, backlight);

Is this needed?

> +
> +	rc = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
> +	if (rc)
> +		return rc;
> +
> +	backlight->brightness = hid_register_report(hdev, HID_FEATURE_REPORT,
> +			APPLE_MAGIC_REPORT_ID_BRIGHTNESS, 0);
> +	backlight->power = hid_register_report(hdev, HID_FEATURE_REPORT,
> +			APPLE_MAGIC_REPORT_ID_POWER, 0);
> +
> +	if (!backlight->brightness || !backlight->power) {
> +		rc = -ENODEV;
> +		goto hw_stop;
> +	}
> +
> +	backlight->hdev = hdev;
> +	backlight->cdev.name = ":white:" LED_FUNCTION_KBD_BACKLIGHT;

> +	backlight->cdev.max_brightness = backlight->brightness->field[0]->logical_maximum;
> +	backlight->cdev.brightness_set_blocking = apple_magic_backlight_led_set;
> +
> +	apple_magic_backlight_set(backlight, 0, 0);
> +
> +	return devm_led_classdev_register(&hdev->dev, &backlight->cdev);
> +
> +hw_stop:
> +	hid_hw_stop(hdev);
> +	return rc;
> +}
> +
> +static const struct hid_device_id apple_magic_backlight_hid_ids[] = {
> +	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_BACKLIGHT) },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(hid, apple_magic_backlight_hid_ids);
> +
> +static struct hid_driver apple_magic_backlight_hid_driver = {
> +	.name = "apple-magic-backlight",
> +	.id_table = apple_magic_backlight_hid_ids,
> +	.probe = apple_magic_backlight_probe,
> +};
> +module_hid_driver(apple_magic_backlight_hid_driver);
> +
> +MODULE_DESCRIPTION("MacBook Magic Keyboard Backlight");
> +MODULE_AUTHOR("Orlando Chamberlain <orlandoch.dev@gmail.com>");
> +MODULE_LICENSE("GPL");
> -- 
> 2.39.1
> 

Note: Only your cover letter has the "v2" prefix.
Normally git format-patch should apply this properly to all patches when
using --reroll-count.

Re: [PATCH 2/2] HID: apple-magic-backlight: Add driver for keyboard backlight on internal Magic Keyboards

[Orlando Chamberlain]

On Thu, 16 Feb 2023 05:41:05 +0000
Thomas Weißschuh <thomas@t-8ch.de> wrote:

> On Thu, Feb 16, 2023 at 03:12:28PM +1100, Orlando Chamberlain wrote:
> > This driver adds support for the keyboard backlight on Intel T2 Macs
> > with internal Magic Keyboards (MacBookPro16,x and MacBookAir9,1)
> > 
> > Signed-off-by: Orlando Chamberlain <orlandoch.dev@gmail.com>
> > Co-developed-by: Kerem Karabay <kekrby@gmail.com>
> > Signed-off-by: Kerem Karabay <kekrby@gmail.com>  
> 
> The last Signed-off-by should be yours.
> See Documentation/process/submitting-patches.rst.

I'll reorder that in v3, thanks for pointing it out.
> 
> > ---
> >  MAINTAINERS                         |   6 ++
> >  drivers/hid/Kconfig                 |  13 +++
> >  drivers/hid/Makefile                |   1 +
> >  drivers/hid/apple-magic-backlight.c | 125
> > ++++++++++++++++++++++++++++ 4 files changed, 145 insertions(+)
> >  create mode 100644 drivers/hid/apple-magic-backlight.c
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index fb1471cb5ed3..3319f0c3ed1e 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -9201,6 +9201,12 @@ F:	include/linux/pm.h
> >  F:	include/linux/suspend.h
> >  F:	kernel/power/
> >  
> > +HID APPLE MAGIC BACKLIGHT DRIVER
> > +M:	Orlando Chamberlain <orlandoch.dev@gmail.com>
> > +L:	linux-input@vger.kernel.org
> > +S:	Maintained
> > +F:	drivers/hid/apple-magic-backlight.c
> > +
> >  HID CORE LAYER
> >  M:	Jiri Kosina <jikos@kernel.org>
> >  M:	Benjamin Tissoires <benjamin.tissoires@redhat.com>
> > diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> > index e2a5d30c8895..f4702d32ce2f 100644
> > --- a/drivers/hid/Kconfig
> > +++ b/drivers/hid/Kconfig
> > @@ -130,6 +130,19 @@ config HID_APPLE
> >  	Say Y here if you want support for keyboards of
> > Apple iBooks, PowerBooks, MacBooks, MacBook Pros and Apple Aluminum.
> >  
> > +config HID_APPLE_MAGIC_BACKLIGHT
> > +	tristate "Apple Magic Keyboard Backlight"
> > +	depends on USB_HID
> > +	depends on LEDS_CLASS
> > +	depends on NEW_LEDS
> > +	help
> > +	Say Y here if you want support for the keyboard backlight
> > on Macs with
> > +	the magic keyboard (MacBookPro16,x and MacBookAir9,1).
> > Note that this
> > +	driver is not for external magic keyboards.
> > +
> > +	To compile this driver as a module, choose M here: the
> > +	module will be called apple-magic-backlight.
> > +
> >  config HID_APPLEIR
> >  	tristate "Apple infrared receiver"
> >  	depends on (USB_HID)
> > diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
> > index e8014c1a2f8b..5cbfe85dd31b 100644
> > --- a/drivers/hid/Makefile
> > +++ b/drivers/hid/Makefile
> > @@ -26,6 +26,7 @@ obj-$(CONFIG_HID_ACCUTOUCH)	+=
> > hid-accutouch.o obj-$(CONFIG_HID_ALPS)		+= hid-alps.o
> >  obj-$(CONFIG_HID_ACRUX)		+= hid-axff.o
> >  obj-$(CONFIG_HID_APPLE)		+= hid-apple.o
> > +obj-$(CONFIG_HID_APPLE_MAGIC_BACKLIGHT)	+=
> > apple-magic-backlight.o obj-$(CONFIG_HID_APPLEIR)	+=
> > hid-appleir.o obj-$(CONFIG_HID_CREATIVE_SB0540)	+=
> > hid-creative-sb0540.o obj-$(CONFIG_HID_ASUS)		+=
> > hid-asus.o diff --git a/drivers/hid/apple-magic-backlight.c
> > b/drivers/hid/apple-magic-backlight.c new file mode 100644
> > index 000000000000..ed5bcf5bb599
> > --- /dev/null
> > +++ b/drivers/hid/apple-magic-backlight.c
> > @@ -0,0 +1,125 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Apple Magic Keyboard Backlight Driver
> > + *
> > + * For Intel Macs with internal Magic Keyboard (MacBookPro16,1-4
> > and MacBookAir9,1)
> > + *
> > + * Copyright (c) 2022 Kerem Karabay <kekrby@gmail.com>
> > + * Copyright (c) 2023 Orlando Chamberlain <orlandoch.dev@gmail.com>
> > + */
> > +
> > +#include <linux/hid.h>
> > +#include <linux/usb.h>  
> 
> No need for linux/usb.h.

I'll fix that in v3.

> 
> > +#include <linux/leds.h>
> > +#include <linux/device.h>
> > +#include <linux/errno.h>
> > +#include <dt-bindings/leds/common.h>
> > +
> > +#include "hid-ids.h"
> > +
> > +#define HID_USAGE_MAGIC_BL	0xff00000f
> > +
> > +#define APPLE_MAGIC_REPORT_ID_POWER 3
> > +#define APPLE_MAGIC_REPORT_ID_BRIGHTNESS 1
> > +
> > +struct apple_magic_backlight {
> > +	struct led_classdev cdev;
> > +	struct hid_device *hdev;
> > +	struct hid_report *brightness;
> > +	struct hid_report *power;
> > +};
> > +
> > +static void apple_magic_backlight_report_set(struct hid_report
> > *rep, u16 value, u8 rate) +{  
> 
> Could "value" be a s32? "logical_maximum" from the field is a s32,
> so there is no risk of truncation.

That makes sense, I'll put it in v3.

> 
> > +	rep->field[0]->value[0] = value;
> > +	rep->field[1]->value[0] = 0x5e; /* Mimic Windows */
> > +	rep->field[1]->value[0] |= rate << 8;
> > +
> > +	hid_hw_request(rep->device, rep, HID_REQ_SET_REPORT);
> > +}
> > +
> > +static void apple_magic_backlight_set(struct apple_magic_backlight
> > *backlight,
> > +				     int brightness, char rate)
> > +{
> > +	apple_magic_backlight_report_set(backlight->power,
> > brightness ? 1 : 0, rate);
> > +	if (brightness)
> > +
> > apple_magic_backlight_report_set(backlight->brightness, brightness,
> > rate); +} +
> > +static int apple_magic_backlight_led_set(struct led_classdev
> > *led_cdev,
> > +					 enum led_brightness
> > brightness) +{
> > +	struct apple_magic_backlight *backlight =
> > container_of(led_cdev,
> > +			struct apple_magic_backlight, cdev);
> > +
> > +	apple_magic_backlight_set(backlight, brightness, 1);
> > +	return 0;
> > +}
> > +
> > +static int apple_magic_backlight_probe(struct hid_device *hdev,
> > +				       const struct hid_device_id
> > *id) +{
> > +	struct apple_magic_backlight *backlight;
> > +	int rc;
> > +
> > +	rc = hid_parse(hdev);
> > +	if (rc)
> > +		return rc;
> > +
> > +	/*
> > +	 * Ensure this usb endpoint is for the keyboard backlight,
> > not touchbar
> > +	 * backlight.
> > +	 */
> > +	if (!(hdev->collection && hdev->collection[0].usage ==
> > HID_USAGE_MAGIC_BL))
> > +		return -ENODEV;  
> 
> I don't think hdev->collection can ever be NULL.

I'll remove that check, I don't think it ever was null for me.

> 
> Also personally I would prefer this:
> 
> !hdev->collection || hdev->collection[0].usage != HID_USAGE_MAGIC_BL

That is neater, I'll use it in v3.

> 
> Like it is done with the reports below.
> 
> > +
> > +	backlight = devm_kzalloc(&hdev->dev, sizeof(*backlight),
> > GFP_KERNEL);
> > +	if (!backlight)
> > +		return -ENOMEM;
> > +
> > +	hid_set_drvdata(hdev, backlight);  
> 
> Is this needed?

Nope, I'll take that out in v3.

> 
> > +
> > +	rc = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
> > +	if (rc)
> > +		return rc;
> > +
> > +	backlight->brightness = hid_register_report(hdev,
> > HID_FEATURE_REPORT,
> > +			APPLE_MAGIC_REPORT_ID_BRIGHTNESS, 0);
> > +	backlight->power = hid_register_report(hdev,
> > HID_FEATURE_REPORT,
> > +			APPLE_MAGIC_REPORT_ID_POWER, 0);
> > +
> > +	if (!backlight->brightness || !backlight->power) {
> > +		rc = -ENODEV;
> > +		goto hw_stop;
> > +	}
> > +
> > +	backlight->hdev = hdev;
> > +	backlight->cdev.name = ":white:"
> > LED_FUNCTION_KBD_BACKLIGHT;  
> 
> > +	backlight->cdev.max_brightness =
> > backlight->brightness->field[0]->logical_maximum;
> > +	backlight->cdev.brightness_set_blocking =
> > apple_magic_backlight_led_set; +
> > +	apple_magic_backlight_set(backlight, 0, 0);
> > +
> > +	return devm_led_classdev_register(&hdev->dev,
> > &backlight->cdev); +
> > +hw_stop:
> > +	hid_hw_stop(hdev);
> > +	return rc;
> > +}
> > +
> > +static const struct hid_device_id apple_magic_backlight_hid_ids[]
> > = {
> > +	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE,
> > USB_DEVICE_ID_APPLE_TOUCHBAR_BACKLIGHT) },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(hid, apple_magic_backlight_hid_ids);
> > +
> > +static struct hid_driver apple_magic_backlight_hid_driver = {
> > +	.name = "apple-magic-backlight",
> > +	.id_table = apple_magic_backlight_hid_ids,
> > +	.probe = apple_magic_backlight_probe,
> > +};
> > +module_hid_driver(apple_magic_backlight_hid_driver);
> > +
> > +MODULE_DESCRIPTION("MacBook Magic Keyboard Backlight");
> > +MODULE_AUTHOR("Orlando Chamberlain <orlandoch.dev@gmail.com>");
> > +MODULE_LICENSE("GPL");
> > -- 
> > 2.39.1
> >   
> 
> Note: Only your cover letter has the "v2" prefix.
> Normally git format-patch should apply this properly to all patches
> when using --reroll-count.

I realised that after I sent the patches, I had manually added v2 to
the cover letter but I forgot about the patches themselves. I didn't
know about --reroll-count, thanks!

Re: [PATCH 2/2] HID: apple-magic-backlight: Add driver for keyboard backlight on internal Magic Keyboards

[Orlando Chamberlain]

On Thu, 16 Feb 2023 15:12:28 +1100
Orlando Chamberlain <orlandoch.dev@gmail.com> wrote:

> This driver adds support for the keyboard backlight on Intel T2 Macs
> with internal Magic Keyboards (MacBookPro16,x and MacBookAir9,1)
> 
> Signed-off-by: Orlando Chamberlain <orlandoch.dev@gmail.com>
> Co-developed-by: Kerem Karabay <kekrby@gmail.com>
> Signed-off-by: Kerem Karabay <kekrby@gmail.com>
> ---
>  MAINTAINERS                         |   6 ++
>  drivers/hid/Kconfig                 |  13 +++
>  drivers/hid/Makefile                |   1 +
>  drivers/hid/apple-magic-backlight.c | 125

A general question to the hid/input folks:

Is it alright that this doesn't start with "hid-"? All the other
drivers start with that so I'm not sure if its an issue. If it is, then
I can rename it to "hid-apple-magic-backlight".

> ++++++++++++++++++++++++++++ 4 files changed, 145 insertions(+)
>  create mode 100644 drivers/hid/apple-magic-backlight.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fb1471cb5ed3..3319f0c3ed1e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9201,6 +9201,12 @@ F:	include/linux/pm.h
>  F:	include/linux/suspend.h
>  F:	kernel/power/
>  
> +HID APPLE MAGIC BACKLIGHT DRIVER
> +M:	Orlando Chamberlain <orlandoch.dev@gmail.com>
> +L:	linux-input@vger.kernel.org
> +S:	Maintained
> +F:	drivers/hid/apple-magic-backlight.c
> +
>  HID CORE LAYER
>  M:	Jiri Kosina <jikos@kernel.org>
>  M:	Benjamin Tissoires <benjamin.tissoires@redhat.com>
> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> index e2a5d30c8895..f4702d32ce2f 100644
> --- a/drivers/hid/Kconfig
> +++ b/drivers/hid/Kconfig
> @@ -130,6 +130,19 @@ config HID_APPLE
>  	Say Y here if you want support for keyboards of	Apple
> iBooks, PowerBooks, MacBooks, MacBook Pros and Apple Aluminum.
>  
> +config HID_APPLE_MAGIC_BACKLIGHT
> +	tristate "Apple Magic Keyboard Backlight"
> +	depends on USB_HID
> +	depends on LEDS_CLASS
> +	depends on NEW_LEDS
> +	help
> +	Say Y here if you want support for the keyboard backlight on
> Macs with
> +	the magic keyboard (MacBookPro16,x and MacBookAir9,1). Note
> that this
> +	driver is not for external magic keyboards.
> +
> +	To compile this driver as a module, choose M here: the
> +	module will be called apple-magic-backlight.
> +
>  config HID_APPLEIR
>  	tristate "Apple infrared receiver"
>  	depends on (USB_HID)
> diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
> index e8014c1a2f8b..5cbfe85dd31b 100644
> --- a/drivers/hid/Makefile
> +++ b/drivers/hid/Makefile
> @@ -26,6 +26,7 @@ obj-$(CONFIG_HID_ACCUTOUCH)	+=
> hid-accutouch.o obj-$(CONFIG_HID_ALPS)		+= hid-alps.o
>  obj-$(CONFIG_HID_ACRUX)		+= hid-axff.o
>  obj-$(CONFIG_HID_APPLE)		+= hid-apple.o
> +obj-$(CONFIG_HID_APPLE_MAGIC_BACKLIGHT)	+=
> apple-magic-backlight.o obj-$(CONFIG_HID_APPLEIR)	+=
> hid-appleir.o obj-$(CONFIG_HID_CREATIVE_SB0540)	+=
> hid-creative-sb0540.o obj-$(CONFIG_HID_ASUS)		+=
> hid-asus.o diff --git a/drivers/hid/apple-magic-backlight.c
> b/drivers/hid/apple-magic-backlight.c new file mode 100644
> index 000000000000..ed5bcf5bb599
> --- /dev/null
> +++ b/drivers/hid/apple-magic-backlight.c
> @@ -0,0 +1,125 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Apple Magic Keyboard Backlight Driver
> + *
> + * For Intel Macs with internal Magic Keyboard (MacBookPro16,1-4 and
> MacBookAir9,1)
> + *
> + * Copyright (c) 2022 Kerem Karabay <kekrby@gmail.com>
> + * Copyright (c) 2023 Orlando Chamberlain <orlandoch.dev@gmail.com>
> + */
> +
> +#include <linux/hid.h>
> +#include <linux/usb.h>
> +#include <linux/leds.h>
> +#include <linux/device.h>
> +#include <linux/errno.h>
> +#include <dt-bindings/leds/common.h>
> +
> +#include "hid-ids.h"
> +
> +#define HID_USAGE_MAGIC_BL	0xff00000f
> +
> +#define APPLE_MAGIC_REPORT_ID_POWER 3
> +#define APPLE_MAGIC_REPORT_ID_BRIGHTNESS 1
> +
> +struct apple_magic_backlight {
> +	struct led_classdev cdev;
> +	struct hid_device *hdev;
> +	struct hid_report *brightness;
> +	struct hid_report *power;
> +};
> +
> +static void apple_magic_backlight_report_set(struct hid_report *rep,
> u16 value, u8 rate) +{
> +	rep->field[0]->value[0] = value;
> +	rep->field[1]->value[0] = 0x5e; /* Mimic Windows */
> +	rep->field[1]->value[0] |= rate << 8;
> +
> +	hid_hw_request(rep->device, rep, HID_REQ_SET_REPORT);
> +}
> +
> +static void apple_magic_backlight_set(struct apple_magic_backlight
> *backlight,
> +				     int brightness, char rate)
> +{
> +	apple_magic_backlight_report_set(backlight->power,
> brightness ? 1 : 0, rate);
> +	if (brightness)
> +
> apple_magic_backlight_report_set(backlight->brightness, brightness,
> rate); +} +
> +static int apple_magic_backlight_led_set(struct led_classdev
> *led_cdev,
> +					 enum led_brightness
> brightness) +{
> +	struct apple_magic_backlight *backlight =
> container_of(led_cdev,
> +			struct apple_magic_backlight, cdev);
> +
> +	apple_magic_backlight_set(backlight, brightness, 1);
> +	return 0;
> +}
> +
> +static int apple_magic_backlight_probe(struct hid_device *hdev,
> +				       const struct hid_device_id
> *id) +{
> +	struct apple_magic_backlight *backlight;
> +	int rc;
> +
> +	rc = hid_parse(hdev);
> +	if (rc)
> +		return rc;
> +
> +	/*
> +	 * Ensure this usb endpoint is for the keyboard backlight,
> not touchbar
> +	 * backlight.
> +	 */
> +	if (!(hdev->collection && hdev->collection[0].usage ==
> HID_USAGE_MAGIC_BL))
> +		return -ENODEV;
> +
> +	backlight = devm_kzalloc(&hdev->dev, sizeof(*backlight),
> GFP_KERNEL);
> +	if (!backlight)
> +		return -ENOMEM;
> +
> +	hid_set_drvdata(hdev, backlight);
> +
> +	rc = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
> +	if (rc)
> +		return rc;
> +
> +	backlight->brightness = hid_register_report(hdev,
> HID_FEATURE_REPORT,
> +			APPLE_MAGIC_REPORT_ID_BRIGHTNESS, 0);
> +	backlight->power = hid_register_report(hdev,
> HID_FEATURE_REPORT,
> +			APPLE_MAGIC_REPORT_ID_POWER, 0);
> +
> +	if (!backlight->brightness || !backlight->power) {
> +		rc = -ENODEV;
> +		goto hw_stop;
> +	}
> +
> +	backlight->hdev = hdev;
> +	backlight->cdev.name = ":white:" LED_FUNCTION_KBD_BACKLIGHT;
> +	backlight->cdev.max_brightness =
> backlight->brightness->field[0]->logical_maximum;
> +	backlight->cdev.brightness_set_blocking =
> apple_magic_backlight_led_set; +
> +	apple_magic_backlight_set(backlight, 0, 0);
> +
> +	return devm_led_classdev_register(&hdev->dev,
> &backlight->cdev); +
> +hw_stop:
> +	hid_hw_stop(hdev);
> +	return rc;
> +}
> +
> +static const struct hid_device_id apple_magic_backlight_hid_ids[] = {
> +	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE,
> USB_DEVICE_ID_APPLE_TOUCHBAR_BACKLIGHT) },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(hid, apple_magic_backlight_hid_ids);
> +
> +static struct hid_driver apple_magic_backlight_hid_driver = {
> +	.name = "apple-magic-backlight",
> +	.id_table = apple_magic_backlight_hid_ids,
> +	.probe = apple_magic_backlight_probe,
> +};
> +module_hid_driver(apple_magic_backlight_hid_driver);
> +
> +MODULE_DESCRIPTION("MacBook Magic Keyboard Backlight");
> +MODULE_AUTHOR("Orlando Chamberlain <orlandoch.dev@gmail.com>");
> +MODULE_LICENSE("GPL");

Re: [PATCH 2/2] HID: apple-magic-backlight: Add driver for keyboard backlight on internal Magic Keyboards

[Andy Shevchenko]

On Thu, Feb 16, 2023 at 10:15 AM Orlando Chamberlain
<orlandoch.dev@gmail.com> wrote:
> On Thu, 16 Feb 2023 15:12:28 +1100
> Orlando Chamberlain <orlandoch.dev@gmail.com> wrote:

...

> >  drivers/hid/apple-magic-backlight.c | 125
>
> A general question to the hid/input folks:
>
> Is it alright that this doesn't start with "hid-"? All the other
> drivers start with that so I'm not sure if its an issue.

What makes apple so special?

> If it is, then
> I can rename it to "hid-apple-magic-backlight".

If there is a good justification of not doing that, put it into the
commit message.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 2/2] HID: apple-magic-backlight: Add driver for keyboard backlight on internal Magic Keyboards

[Andy Shevchenko]

On Thu, Feb 16, 2023 at 7:41 AM Thomas Weißschuh <thomas@t-8ch.de> wrote:
> On Thu, Feb 16, 2023 at 03:12:28PM +1100, Orlando Chamberlain wrote:

...

> Note: Only your cover letter has the "v2" prefix.
> Normally git format-patch should apply this properly to all patches when
> using --reroll-count.

There is an option -v<X>, where <X> is a version applied to all
patches in the lot.

-- 
With Best Regards,
Andy Shevchenko