Re: [PATCH v3 2/2] HID: hid-apple-magic-backlight: Add driver for keyboard backlight on internal Magic Keyboards

[Andy Shevchenko]

On Fri, Feb 17, 2023 at 12:24 PM Orlando Chamberlain
<orlandoch.dev@xxxxxxxxx> wrote:
>
> This driver adds support for the keyboard backlight on Intel T2 Macs
> with internal Magic Keyboards (MacBookPro16,x and MacBookAir9,1)

LGTM,
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

> Co-developed-by: Kerem Karabay <kekrby@xxxxxxxxx>
> Signed-off-by: Kerem Karabay <kekrby@xxxxxxxxx>
> Signed-off-by: Orlando Chamberlain <orlandoch.dev@xxxxxxxxx>
> ---
> v2->v3:
> - remove unneeded inclusion
> - use s32 for report value type
> - remove unneeded null check
> - don't set drvdata as its never used
> - prepend "hid-" to module name
> 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
>  MAINTAINERS                             |   6 ++
>  drivers/hid/Kconfig                     |  13 +++
>  drivers/hid/Makefile                    |   1 +
>  drivers/hid/hid-apple-magic-backlight.c | 122 ++++++++++++++++++++++++
>  4 files changed, 142 insertions(+)
>  create mode 100644 drivers/hid/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@xxxxxxxxx>
> +L:     linux-input@xxxxxxxxxxxxxxx
> +S:     Maintained
> +F:     drivers/hid/apple-magic-backlight.c
> +
>  HID CORE LAYER
>  M:     Jiri Kosina <jikos@xxxxxxxxxx>
>  M:     Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> index e2a5d30c8895..fe489632bfd9 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 hid-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..dc8df002bc86 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-$(CONFIG_HID_APPLE_MAGIC_BACKLIGHT)        += hid-apple-magic-backlight.o
>  obj-$(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/hid-apple-magic-backlight.c b/drivers/hid/hid-apple-magic-backlight.c
> new file mode 100644
> index 000000000000..210af2849e78
> --- /dev/null
> +++ b/drivers/hid/hid-apple-magic-backlight.c
> @@ -0,0 +1,122 @@
> +// 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@xxxxxxxxx>
> + * Copyright (c) 2023 Orlando Chamberlain <orlandoch.dev@xxxxxxxxx>
> + */
> +
> +#include <linux/hid.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, s32 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[0].usage != HID_USAGE_MAGIC_BL)
> +               return -ENODEV;
> +
> +       backlight = devm_kzalloc(&hdev->dev, sizeof(*backlight), GFP_KERNEL);
> +       if (!backlight)
> +               return -ENOMEM;
> +
> +       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 = "hid-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@xxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> --
> 2.39.1
>


-- 
With Best Regards,
Andy Shevchenko