Re: [PATCH v4 2/2] HID: hid-apple-magic-backlight: Add driver for keyboard backlight on internal Magic Keyboards

[Orlando Chamberlain]

On Mon, 20 Feb 2023 08:33:10 +0000
Aditya Garg <gargaditya08@xxxxxxxx> wrote:

> > On 18-Feb-2023, at 2:38 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)
> > 
> > Co-developed-by: Kerem Karabay <kekrby@xxxxxxxxx>
> > Signed-off-by: Kerem Karabay <kekrby@xxxxxxxxx>
> > Signed-off-by: Orlando Chamberlain <orlandoch.dev@xxxxxxxxx>
> > Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> > Reviewed-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
> > ---
> > v3->v4:
> > - collect reviews from Andy and Thomas
> > - remove now unused hdev member of apple_magic_backlight
> > 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 | 120
> > ++++++++++++++++++++++++ 4 files changed, 140 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  
> 
> drivers/hid/hid-apple-magic-backlight.c
> 
> Looks like you forgot to change that.

Yes I did, thanks for catching that. I'll fix it in v5.
> 
> > +
> > 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..f0fc02ff3b2d
> > --- /dev/null
> > +++ b/drivers/hid/hid-apple-magic-backlight.c
> > @@ -0,0 +1,120 @@
> > +// 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_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->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
> >