[PATCH v3] platform/x86: ideapad-laptop: Add support for keyboard backlights using KBLC ACPI symbol
From: Stuart Hayhurst
Date: Sun Aug 27 2023 - 12:28:43 EST
Newer Lenovo laptops seem to use the KBLC symbol to control the backlight
Add support for handling the keyboard backlight on these devices
Signed-off-by: Stuart Hayhurst <stuart.a.hayhurst@xxxxxxxxx>
---
Thanks, applied your feedback
v1 -> v2:
- Replace keyboard identification hex literals with defines
- Use a helper macro for checking a keyboard type is tristate
- Reworked ideapad_kbd_bl_brightness_set
- Reworked ideapad_kbd_bl_brightness_get
- Clean up newlines and stray change
- Use GENMASK, FIELD_GET and FIELD_PUT instead of manual masking and shifting
- Correct format specifiers for new warnings
v2 -> v3:
- Use named define for keyboard brightness event
- Replaced CHECK_KBD_BL_TRISTATE macro with static function
- Dropped _MASK suffix for bit masking
- Use FIELD_PREP for the get command too
- Ignore least significant bit in KBD__BL_GET_BRIGHTNESS mask
---
drivers/platform/x86/ideapad-laptop.c | 118 ++++++++++++++++++++++++--
1 file changed, 112 insertions(+), 6 deletions(-)
diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
index d2fee9a3e239..4a19a396fc3b 100644
--- a/drivers/platform/x86/ideapad-laptop.c
+++ b/drivers/platform/x86/ideapad-laptop.c
@@ -10,6 +10,7 @@
#include <linux/acpi.h>
#include <linux/backlight.h>
+#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/debugfs.h>
@@ -85,6 +86,31 @@ enum {
SALS_FNLOCK_OFF = 0xf,
};
+/*
+ * These correspond to the number of supported states - 1
+ * Future keyboard types may need a new system, if there's a collision
+ * KBD_BL_TRISTATE_AUTO has no way to report or set the auto state
+ * so it effectively has 3 states, but needs to handle 4
+ */
+enum {
+ KBD_BL_STANDARD = 1,
+ KBD_BL_TRISTATE = 2,
+ KBD_BL_TRISTATE_AUTO = 3,
+};
+
+#define KBD_BL_QUERY_TYPE 0x1
+#define KBD_BL_TRISTATE_TYPE 0x5
+#define KBD_BL_TRISTATE_AUTO_TYPE 0x7
+
+#define KBD_BL_COMMAND_GET 0x2
+#define KBD_BL_COMMAND_SET 0x3
+#define KBD_BL_COMMAND_TYPE GENMASK(7, 4)
+
+#define KBD_BL_GET_BRIGHTNESS GENMASK(15, 1)
+#define KBD_BL_SET_BRIGHTNESS GENMASK(19, 16)
+
+#define KBD_BL_KBLC_CHANGED_EVENT 12
+
struct ideapad_dytc_priv {
enum platform_profile_option current_profile;
struct platform_profile_handler pprof;
@@ -122,6 +148,7 @@ struct ideapad_private {
} features;
struct {
bool initialized;
+ int type;
struct led_classdev led;
unsigned int last_brightness;
} kbd_bl;
@@ -242,6 +269,16 @@ static int exec_sals(acpi_handle handle, unsigned long arg)
return exec_simple_method(handle, "SALS", arg);
}
+static int exec_kblc(acpi_handle handle, unsigned long arg)
+{
+ return exec_simple_method(handle, "KBLC", arg);
+}
+
+static int eval_kblc(acpi_handle handle, unsigned long cmd, unsigned long *res)
+{
+ return eval_int_with_arg(handle, "KBLC", cmd, res);
+}
+
static int eval_dytc(acpi_handle handle, unsigned long cmd, unsigned long *res)
{
return eval_int_with_arg(handle, "DYTC", cmd, res);
@@ -1270,16 +1307,47 @@ static void ideapad_backlight_notify_brightness(struct ideapad_private *priv)
/*
* keyboard backlight
*/
+static int ideapad_kbd_bl_check_tristate(int type)
+{
+ return (type == KBD_BL_TRISTATE) || (type == KBD_BL_TRISTATE_AUTO);
+}
+
static int ideapad_kbd_bl_brightness_get(struct ideapad_private *priv)
{
- unsigned long hals;
+ unsigned long value;
int err;
- err = eval_hals(priv->adev->handle, &hals);
+ if (ideapad_kbd_bl_check_tristate(priv->kbd_bl.type)) {
+ err = eval_kblc(priv->adev->handle,
+ FIELD_PREP(KBD_BL_COMMAND_TYPE, priv->kbd_bl.type) |
+ KBD_BL_COMMAND_GET,
+ &value);
+
+ if (err)
+ return err;
+
+ /* Convert returned value to brightness level */
+ value = FIELD_GET(KBD_BL_GET_BRIGHTNESS, value);
+
+ /* Off, low or high */
+ if (value <= priv->kbd_bl.led.max_brightness)
+ return value;
+
+ /* Auto, report as off */
+ if (value == priv->kbd_bl.led.max_brightness + 1)
+ return 0;
+
+ /* Unknown value */
+ dev_warn(&priv->platform_device->dev,
+ "Unknown keyboard backlight value: %lu", value);
+ return -EINVAL;
+ }
+
+ err = eval_hals(priv->adev->handle, &value);
if (err)
return err;
- return !!test_bit(HALS_KBD_BL_STATE_BIT, &hals);
+ return !!test_bit(HALS_KBD_BL_STATE_BIT, &value);
}
static enum led_brightness ideapad_kbd_bl_led_cdev_brightness_get(struct led_classdev *led_cdev)
@@ -1291,7 +1359,21 @@ static enum led_brightness ideapad_kbd_bl_led_cdev_brightness_get(struct led_cla
static int ideapad_kbd_bl_brightness_set(struct ideapad_private *priv, unsigned int brightness)
{
- int err = exec_sals(priv->adev->handle, brightness ? SALS_KBD_BL_ON : SALS_KBD_BL_OFF);
+ int err;
+ unsigned long value;
+ int type = priv->kbd_bl.type;
+
+ if (ideapad_kbd_bl_check_tristate(type)) {
+ if (brightness > priv->kbd_bl.led.max_brightness)
+ return -EINVAL;
+
+ value = FIELD_PREP(KBD_BL_SET_BRIGHTNESS, brightness) |
+ FIELD_PREP(KBD_BL_COMMAND_TYPE, type) |
+ KBD_BL_COMMAND_SET;
+ err = exec_kblc(priv->adev->handle, value);
+ } else {
+ err = exec_sals(priv->adev->handle, brightness ? SALS_KBD_BL_ON : SALS_KBD_BL_OFF);
+ }
if (err)
return err;
@@ -1344,8 +1426,13 @@ static int ideapad_kbd_bl_init(struct ideapad_private *priv)
priv->kbd_bl.last_brightness = brightness;
+ if (ideapad_kbd_bl_check_tristate(priv->kbd_bl.type)) {
+ priv->kbd_bl.led.max_brightness = 2;
+ } else {
+ priv->kbd_bl.led.max_brightness = 1;
+ }
+
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;
@@ -1456,6 +1543,7 @@ static void ideapad_acpi_notify(acpi_handle handle, u32 event, void *data)
case 2:
ideapad_backlight_notify_power(priv);
break;
+ case KBD_BL_KBLC_CHANGED_EVENT:
case 1:
/*
* Some IdeaPads report event 1 every ~20
@@ -1557,13 +1645,31 @@ static void ideapad_check_features(struct ideapad_private *priv)
if (test_bit(HALS_FNLOCK_SUPPORT_BIT, &val))
priv->features.fn_lock = true;
- if (test_bit(HALS_KBD_BL_SUPPORT_BIT, &val))
+ if (test_bit(HALS_KBD_BL_SUPPORT_BIT, &val)) {
priv->features.kbd_bl = true;
+ priv->kbd_bl.type = KBD_BL_STANDARD;
+ }
if (test_bit(HALS_USB_CHARGING_SUPPORT_BIT, &val))
priv->features.usb_charging = true;
}
}
+
+ if (acpi_has_method(handle, "KBLC")) {
+ if (!eval_kblc(priv->adev->handle, KBD_BL_QUERY_TYPE, &val)) {
+ if (val == KBD_BL_TRISTATE_TYPE) {
+ priv->features.kbd_bl = true;
+ priv->kbd_bl.type = KBD_BL_TRISTATE;
+ } else if (val == KBD_BL_TRISTATE_AUTO_TYPE) {
+ priv->features.kbd_bl = true;
+ priv->kbd_bl.type = KBD_BL_TRISTATE_AUTO;
+ } else {
+ dev_warn(&priv->platform_device->dev,
+ "Unknown keyboard type: %lu",
+ val);
+ }
+ }
+ }
}
#if IS_ENABLED(CONFIG_ACPI_WMI)
--
2.40.1.521.gf1e218fcd8