Re: [PATCH v6 1/1] platform/x86: asus-wmi: add support for ASUS screenpad

From: Hans de Goede
Date: Mon Sep 11 2023 - 18:17:02 EST

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Hi Luke,

Thank you for the updated patch.

On 8/30/23 05:22, Luke D. Jones wrote:
> Add support for the WMI methods used to turn off and adjust the
> brightness of the secondary "screenpad" device found on some high-end
> ASUS laptops like the GX650P series and others.
>
> There are some small quirks with this device when considering only the
> raw WMI methods:
> 1. The Off method can only switch the device off
> 2. Changing the brightness turns the device back on
> 3. To turn the device back on the brightness must be > 1
> 4. When the device is off the brightness can't be changed (so it is
> stored by the driver if device is off).
> 5. Booting with a value of 0 brightness (retained by bios) means the bios
> will set a value of >0 <15
> 6. When the device is off it is "unplugged"
>
> asus_wmi sets the minimum brightness as 20 in general use, and 60 for
> booting with values <= min.
>
> The ACPI methods are used in a new backlight device named asus_screenpad.
>
> Signed-off-by: Luke D. Jones <luke@xxxxxxxxxx>
> ---
> drivers/platform/x86/asus-wmi.c | 133 +++++++++++++++++++++
> drivers/platform/x86/asus-wmi.h | 1 +
> include/linux/platform_data/x86/asus-wmi.h | 4 +
> 3 files changed, 138 insertions(+)
>
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index f54178d6f780..0b13be703856 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -25,6 +25,7 @@
> #include <linux/input/sparse-keymap.h>
> #include <linux/kernel.h>
> #include <linux/leds.h>
> +#include <linux/minmax.h>
> #include <linux/module.h>
> #include <linux/pci.h>
> #include <linux/pci_hotplug.h>
> @@ -127,6 +128,10 @@ module_param(fnlock_default, bool, 0444);
> #define NVIDIA_TEMP_MIN 75
> #define NVIDIA_TEMP_MAX 87
>
> +#define ASUS_SCREENPAD_BRIGHT_MIN 20
> +#define ASUS_SCREENPAD_BRIGHT_MAX 255
> +#define ASUS_SCREENPAD_BRIGHT_DEFAULT 60
> +
> static const char * const ashs_ids[] = { "ATK4001", "ATK4002", NULL };
>
> static int throttle_thermal_policy_write(struct asus_wmi *);
> @@ -212,6 +217,7 @@ struct asus_wmi {
>
> struct input_dev *inputdev;
> struct backlight_device *backlight_device;
> + struct backlight_device *screenpad_backlight_device;
> struct platform_device *platform_device;
>
> struct led_classdev wlan_led;
> @@ -3776,6 +3782,124 @@ static int is_display_toggle(int code)
> return 0;
> }
>
> +/* Screenpad backlight *******************************************************/
> +
> +static int read_screenpad_backlight_power(struct asus_wmi *asus)
> +{
> + int ret;
> +
> + ret = asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_SCREENPAD_POWER);
> + if (ret < 0)
> + return ret;
> + /* 1 == powered */
> + return ret ? FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN;
> +}
> +
> +static int read_screenpad_brightness(struct backlight_device *bd)
> +{
> + struct asus_wmi *asus = bl_get_data(bd);
> + u32 retval;
> + int err;
> +
> + err = read_screenpad_backlight_power(asus);
> + if (err < 0)
> + return err;
> + /* The device brightness can only be read if powered, so return stored */
> + if (err == FB_BLANK_POWERDOWN)
> + return asus->driver->screenpad_brightness - ASUS_SCREENPAD_BRIGHT_MIN;
> +
> + err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_SCREENPAD_LIGHT, &retval);
> + if (err < 0)
> + return err;
> +
> + return (retval & ASUS_WMI_DSTS_BRIGHTNESS_MASK) - ASUS_SCREENPAD_BRIGHT_MIN;
> +}
> +
> +static int update_screenpad_bl_status(struct backlight_device *bd)
> +{
> + struct asus_wmi *asus = bl_get_data(bd);
> + int power, err = 0;
> + u32 ctrl_param;
> +
> + power = read_screenpad_backlight_power(asus);
> + if (power < 0)
> + return power;
> +
> + if (bd->props.power != power) {
> + if (power != FB_BLANK_UNBLANK) {
> + /* Only brightness > 0 can power it back on */
> + ctrl_param = asus->driver->screenpad_brightness - ASUS_SCREENPAD_BRIGHT_MIN;
> + err = asus_wmi_set_devstate(ASUS_WMI_DEVID_SCREENPAD_LIGHT,
> + ctrl_param, NULL);
> + } else {
> + err = asus_wmi_set_devstate(ASUS_WMI_DEVID_SCREENPAD_POWER, 0, NULL);
> + }
> + } else if (power == FB_BLANK_UNBLANK) {
> + /* Only set brightness if powered on or we get invalid/unsync state */
> + ctrl_param = bd->props.brightness + ASUS_SCREENPAD_BRIGHT_MIN;
> + err = asus_wmi_set_devstate(ASUS_WMI_DEVID_SCREENPAD_LIGHT, ctrl_param, NULL);
> + }
> +
> + /* Ensure brightness is stored to turn back on with */
> + if (err == 0)
> + asus->driver->screenpad_brightness = bd->props.brightness + ASUS_SCREENPAD_BRIGHT_MIN;
> +
> + return err;
> +}
> +
> +static const struct backlight_ops asus_screenpad_bl_ops = {
> + .get_brightness = read_screenpad_brightness,
> + .update_status = update_screenpad_bl_status,
> + .options = BL_CORE_SUSPENDRESUME,
> +};
> +
> +static int asus_screenpad_init(struct asus_wmi *asus)
> +{
> + struct backlight_device *bd;
> + struct backlight_properties props;
> + int err, power;
> + int brightness = 0;
> +
> + power = read_screenpad_backlight_power(asus);
> + if (power < 0)
> + return power;
> +
> + if (power != FB_BLANK_POWERDOWN) {
> + err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_SCREENPAD_LIGHT, &brightness);
> + if (err < 0)
> + return err;
> + }
> + /* default to an acceptable min brightness on boot if too low */
> + if (brightness < ASUS_SCREENPAD_BRIGHT_MIN)
> + brightness = ASUS_SCREENPAD_BRIGHT_DEFAULT;
> +
> + memset(&props, 0, sizeof(struct backlight_properties));
> + props.type = BACKLIGHT_RAW; /* ensure this bd is last to be picked */
> + props.max_brightness = ASUS_SCREENPAD_BRIGHT_MAX - ASUS_SCREENPAD_BRIGHT_MIN;
> + bd = backlight_device_register("asus_screenpad",
> + &asus->platform_device->dev, asus,
> + &asus_screenpad_bl_ops, &props);
> + if (IS_ERR(bd)) {
> + pr_err("Could not register backlight device\n");
> + return PTR_ERR(bd);
> + }
> +
> + asus->screenpad_backlight_device = bd;
> + asus->driver->screenpad_brightness = brightness;
> + bd->props.brightness = brightness;

This should be:

bd->props.brightness = brightness - ASUS_SCREENPAD_BRIGHT_MIN;

Since this is the value exported to userspace which is down-shited
by ASUS_SCREENPAD_BRIGHT_MIN to start at 0.

I have fixed this up while merging this:

Thank you for your patch, I've applied this patch to my review-hans
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans

> + bd->props.power = power;
> + backlight_update_status(bd);
> +
> + return 0;
> +}
> +
> +static void asus_screenpad_exit(struct asus_wmi *asus)
> +{
> + backlight_device_unregister(asus->screenpad_backlight_device);
> +
> + asus->screenpad_backlight_device = NULL;
> +}
> +
> /* Fn-lock ********************************************************************/
>
> static bool asus_wmi_has_fnlock_key(struct asus_wmi *asus)
> @@ -4431,6 +4555,12 @@ static int asus_wmi_add(struct platform_device *pdev)
> } else if (asus->driver->quirks->wmi_backlight_set_devstate)
> err = asus_wmi_set_devstate(ASUS_WMI_DEVID_BACKLIGHT, 2, NULL);
>
> + if (asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_SCREENPAD_LIGHT)) {
> + err = asus_screenpad_init(asus);
> + if (err && err != -ENODEV)
> + goto fail_screenpad;
> + }
> +
> if (asus_wmi_has_fnlock_key(asus)) {
> asus->fnlock_locked = fnlock_default;
> asus_wmi_fnlock_update(asus);
> @@ -4454,6 +4584,8 @@ static int asus_wmi_add(struct platform_device *pdev)
> asus_wmi_backlight_exit(asus);
> fail_backlight:
> asus_wmi_rfkill_exit(asus);
> +fail_screenpad:
> + asus_screenpad_exit(asus);
> fail_rfkill:
> asus_wmi_led_exit(asus);
> fail_leds:
> @@ -4480,6 +4612,7 @@ static int asus_wmi_remove(struct platform_device *device)
> asus = platform_get_drvdata(device);
> wmi_remove_notify_handler(asus->driver->event_guid);
> asus_wmi_backlight_exit(asus);
> + asus_screenpad_exit(asus);
> asus_wmi_input_exit(asus);
> asus_wmi_led_exit(asus);
> asus_wmi_rfkill_exit(asus);
> diff --git a/drivers/platform/x86/asus-wmi.h b/drivers/platform/x86/asus-wmi.h
> index a478ebfd34df..5fbdd0eafa02 100644
> --- a/drivers/platform/x86/asus-wmi.h
> +++ b/drivers/platform/x86/asus-wmi.h
> @@ -57,6 +57,7 @@ struct quirk_entry {
> struct asus_wmi_driver {
> int brightness;
> int panel_power;
> + int screenpad_brightness;
> int wlan_ctrl_by_user;
>
> const char *name;
> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> index 16e99a1c37fc..63e630276499 100644
> --- a/include/linux/platform_data/x86/asus-wmi.h
> +++ b/include/linux/platform_data/x86/asus-wmi.h
> @@ -58,6 +58,10 @@
> #define ASUS_WMI_DEVID_KBD_BACKLIGHT 0x00050021
> #define ASUS_WMI_DEVID_LIGHT_SENSOR 0x00050022 /* ?? */
> #define ASUS_WMI_DEVID_LIGHTBAR 0x00050025
> +/* This can only be used to disable the screen, not re-enable */
> +#define ASUS_WMI_DEVID_SCREENPAD_POWER 0x00050031
> +/* Writing a brightness re-enables the screen if disabled */
> +#define ASUS_WMI_DEVID_SCREENPAD_LIGHT 0x00050032
> #define ASUS_WMI_DEVID_FAN_BOOST_MODE 0x00110018
> #define ASUS_WMI_DEVID_THROTTLE_THERMAL_POLICY 0x00120075
>

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