Hi,
On 12/16/20 2:40 AM, Barnabás Pőcze wrote:
> On certain models it is possible to control/query the keyboard backlight
> via the SALS/HALS ACPI methods. Add support for that, and register an LED
> class device to expose this functionality.
> Tested on: Lenovo YOGA 520-14IKB 80X8
>
> Signed-off-by: Barnabás Pőcze <pobrn@xxxxxxxxxxxxxx>
>
> diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
> index 075056075b2d..a43574e65f61 100644
> --- a/drivers/platform/x86/ideapad-laptop.c
> +++ b/drivers/platform/x86/ideapad-laptop.c
> @@ -9,6 +9,7 @@
> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>
> #include <acpi/video.h>
> +#include <dt-bindings/leds/common.h>
> #include <linux/acpi.h>
> #include <linux/backlight.h>
> #include <linux/bitops.h>
> @@ -22,6 +23,7 @@
> #include <linux/input/sparse-keymap.h>
> #include <linux/jiffies.h>
> #include <linux/kernel.h>
> +#include <linux/leds.h>
> #include <linux/module.h>
> #include <linux/platform_device.h>
> #include <linux/rfkill.h>
I guess you need a "depends on LEDS_CLASS" in the Kconfig for this?
> @@ -56,12 +58,16 @@ enum {
> };
>
> enum {
> + HALS_KBD_BL_SUPPORT_BIT = 4,
> + HALS_KBD_BL_STATE_BIT = 5,
> HALS_FNLOCK_SUPPORT_BIT = 9,
> HALS_FNLOCK_STATE_BIT = 10,
> HALS_HOTKEYS_PRIMARY_BIT = 11,
> };
>
> enum {
> + SALS_KBD_BL_ON = 0x8,
> + SALS_KBD_BL_OFF = 0x9,
> SALS_FNLOCK_ON = 0xe,
> SALS_FNLOCK_OFF = 0xf,
> };
> @@ -114,6 +120,11 @@ struct ideapad_private {
> fn_lock : 1,
> hw_rfkill_switch : 1;
> } features;
> + struct {
> + bool initialized;
> + struct led_classdev led;
> + unsigned int last_brightness;
> + } kbd_bl;
> };
>
> static bool no_bt_rfkill;
> @@ -934,6 +945,110 @@ static void ideapad_backlight_notify_brightness(struct ideapad_private *priv)
> backlight_force_update(priv->blightdev, BACKLIGHT_UPDATE_HOTKEY);
> }
>
> +/*
> + * keyboard backlight
> + */
> +static int ideapad_kbd_bl_brightness_get(struct ideapad_private *priv)
> +{
> + unsigned long hals;
> + int err;
> +
> + err = eval_hals(priv->adev->handle, &hals);
> + if (err)
> + return err;
> +
> + return test_bit(HALS_KBD_BL_STATE_BIT, &hals);
> +}
> +
> +static enum led_brightness ideapad_kbd_bl_led_cdev_brightness_get(struct led_classdev *led_cdev)
> +{
> + struct ideapad_private *priv = container_of(led_cdev, struct ideapad_private, kbd_bl.led);
> +
> + return ideapad_kbd_bl_brightness_get(priv);
> +}
> +
> +static int ideapad_kbd_bl_brightness_set(struct ideapad_private *priv, unsigned int brightness)
> +{
> + int err;
> +
> + err = eval_sals(priv->adev->handle,
> + brightness ? SALS_KBD_BL_ON : SALS_KBD_BL_OFF);
> + if (err)
> + return err;
> +
> + priv->kbd_bl.last_brightness = brightness;
> +
> + return 0;
> +}
> +
> +static int ideapad_kbd_bl_led_cdev_brightness_set(struct led_classdev *led_cdev,
> + enum led_brightness brightness)
> +{
> + struct ideapad_private *priv = container_of(led_cdev, struct ideapad_private, kbd_bl.led);
> +
> + return ideapad_kbd_bl_brightness_set(priv, brightness);
> +}
> +
> +static void ideapad_kbd_bl_notify(struct ideapad_private *priv)
> +{
> + int brightness;
> +
> + if (!priv->kbd_bl.initialized)
> + return;
> +
> + brightness = ideapad_kbd_bl_brightness_get(priv);
> + if (brightness < 0)
> + return;
> +
> + if (brightness == priv->kbd_bl.last_brightness)
> + return;
> +
> + priv->kbd_bl.last_brightness = brightness;
> +
> + led_classdev_notify_brightness_hw_changed(&priv->kbd_bl.led, brightness);
> +}
So I guess that there is some hotkey combo on the laptops keyboards which
directly changes the state of the kbd backlight "underneath" us and that
is why this is necessary ?
> +
> +static int ideapad_kbd_bl_init(struct ideapad_private *priv)
> +{
> + unsigned long hals;
> + int err;
> +
> + err = eval_hals(priv->adev->handle, &hals);
> + if (err)
> + return err;
So you are checking for presence of the HALS method here, but not
for SALS which is being used in ideapad_kbd_bl_led_cdev_brightness_set()
and you are needlessly re-evaluating HALS here. Would it not be better
to add a features.kbd_bl flag and set that from ideapad_check_features()
as done for other features ? That would avoid an extra evaluation of
the HALS method and also check for SALS.
You can then still unconditionally call this function but just bail
with -ENODEV if the feature flag is not set.
Otherwise this looks good to me.
Regards,
Hans
> +
> + if (!test_bit(HALS_KBD_BL_SUPPORT_BIT, &hals))
> + return -ENODEV;
> +
> + err = ideapad_kbd_bl_brightness_get(priv);
> + if (err < 0)
> + return err;
> +
> + priv->kbd_bl.last_brightness = err;
> +
> + priv->kbd_bl.led.name = "platform::" LED_FUNCTION_KBD_BACKLIGHT;
> + priv->kbd_bl.led.max_brightness = 1;
> + priv->kbd_bl.led.brightness_get = ideapad_kbd_bl_led_cdev_brightness_get;
> + priv->kbd_bl.led.brightness_set_blocking = ideapad_kbd_bl_led_cdev_brightness_set;
> + priv->kbd_bl.led.flags = LED_BRIGHT_HW_CHANGED;
> +
> + err = led_classdev_register(&priv->platform_device->dev, &priv->kbd_bl.led);
> + if (err)
> + return err;
> +
> + priv->kbd_bl.initialized = true;
> +
> + return 0;
> +}
> +
> +static void ideapad_kbd_bl_exit(struct ideapad_private *priv)
> +{
> + if (!priv->kbd_bl.initialized)
> + return;
> +
> + led_classdev_unregister(&priv->kbd_bl.led);
> +}
> +
> /*
> * module init/exit
> */
> @@ -1000,8 +1115,9 @@ static void ideapad_acpi_notify(acpi_handle handle, u32 event, void *data)
> * Some IdeaPads report event 1 every ~20
> * seconds while on battery power; some
> * report this when changing to/from tablet
> - * mode. Squelch this event.
> + * mode.
> */
> + ideapad_kbd_bl_notify(priv);
> break;
> default:
> dev_warn(&priv->platform_device->dev,
> @@ -1101,6 +1217,11 @@ static int ideapad_acpi_add(struct platform_device *pdev)
> if (err)
> goto input_failed;
>
> + err = ideapad_kbd_bl_init(priv);
> + if (err && err != -ENODEV)
> + dev_warn(&pdev->dev,
> + "Could not register keyboard backlight led: %d\n", err);
> +
> /*
> * On some models without a hw-switch (the yoga 2 13 at least)
> * VPCCMD_W_RF must be explicitly set to 1 for the wifi to work.
> @@ -1161,6 +1282,7 @@ static int ideapad_acpi_add(struct platform_device *pdev)
> for (i = 0; i < IDEAPAD_RFKILL_DEV_NUM; i++)
> ideapad_unregister_rfkill(priv, i);
>
> + ideapad_kbd_bl_exit(priv);
> ideapad_input_exit(priv);
>
> input_failed:
> @@ -1188,6 +1310,7 @@ static int ideapad_acpi_remove(struct platform_device *pdev)
> for (i = 0; i < IDEAPAD_RFKILL_DEV_NUM; i++)
> ideapad_unregister_rfkill(priv, i);
>
> + ideapad_kbd_bl_exit(priv);
> ideapad_input_exit(priv);
> ideapad_debugfs_exit(priv);
> ideapad_sysfs_exit(priv);
>
