platform/x86: asus-wmi: add support for ASUS screenpad

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@ljones.dev>
Link: https://lore.kernel.org/r/20230830032237.42987-2-luke@ljones.dev
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 9f8cea5f9615aabe300d644eafd6d58fefcd275c..928fc74e79b466ec4243821ffee6daa289f7cba8 100644 (file)
--- 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 - ASUS_SCREENPAD_BRIGHT_MIN;
+       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 @@ fail_wmi_handler:
        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 a478ebfd34dfadf28d0be0976df011f4fa854a7b..5fbdd0eafa020d1e501860ec74ff9d63ce29425a 100644 (file)
--- 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 16e99a1c37fc4ee389cd63abb6a500ccaffc4993..63e630276499f88c337c85321d17aed1931aa583 100644 (file)
--- 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