[PATCH v4 2/5] platform/chrome: cros_kbd_led_backlight: separate ACPI backend

Tzung-Bi Shih
2022-05-23T09:09:03Z

cros_kbd_led_backlight uses ACPI_KEYBOARD_BACKLIGHT_WRITE and
ACPI_KEYBOARD_BACKLIGHT_READ for setting and getting the brightness
respectively.

Separate ACPI operations for preparing the driver to support other
backends.

Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
---
Changes from v3:
- Remove CROS_KBD_LED_BACKLIGHT_ACPI Kconfig.
- Remove stub function.

Changes from v2:
- Use #ifdef for boolean CONFIG_CROS_KBD_LED_BACKLIGHT_ACPI.

Changes from v1:
- Update email address accordingly.
- Use CONFIG_ACPI guard per "kernel test robot <lkp@intel.com>" reported an
unused variable issue.

.../platform/chrome/cros_kbd_led_backlight.c | 82 ++++++++++++++++---
1 file changed, 69 insertions(+), 13 deletions(-)

diff --git a/drivers/platform/chrome/cros_kbd_led_backlight.c b/drivers/platform/chrome/cros_kbd_led_backlight.c
index f9587a562bb7..a86d664854ae 100644
--- a/drivers/platform/chrome/cros_kbd_led_backlight.c
+++ b/drivers/platform/chrome/cros_kbd_led_backlight.c
@@ -13,6 +13,33 @@
#include <linux/platform_device.h>
#include <linux/slab.h>

+/**
+ * struct keyboard_led_drvdata - keyboard LED driver data.
+ * @init: Init function.
+ * @brightness_get: Get LED brightness level.
+ * @brightness_set: Set LED brightness level. Must not sleep.
+ * @brightness_set_blocking: Set LED brightness level. It can block the
+ * caller for the time required for accessing a
+ * LED device register
+ * @max_brightness: Maximum brightness.
+ *
+ * See struct led_classdev in include/linux/leds.h for more details.
+ */
+struct keyboard_led_drvdata {
+ int (*init)(struct platform_device *pdev);
+
+ enum led_brightness (*brightness_get)(struct led_classdev *led_cdev);
+
+ void (*brightness_set)(struct led_classdev *led_cdev,
+ enum led_brightness brightness);
+ int (*brightness_set_blocking)(struct led_classdev *led_cdev,
+ enum led_brightness brightness);
+
+ enum led_brightness max_brightness;
+};
+
+#ifdef CONFIG_ACPI
+
/* Keyboard LED ACPI Device must be defined in firmware */
#define ACPI_KEYBOARD_BACKLIGHT_DEVICE "\\_SB.KBLT"
#define ACPI_KEYBOARD_BACKLIGHT_READ ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBQC"
@@ -20,8 +47,8 @@

#define ACPI_KEYBOARD_BACKLIGHT_MAX 100

-static void keyboard_led_set_brightness(struct led_classdev *cdev,
- enum led_brightness brightness)
+static void keyboard_led_set_brightness_acpi(struct led_classdev *cdev,
+ enum led_brightness brightness)
{
union acpi_object param;
struct acpi_object_list input;
@@ -40,7 +67,7 @@ static void keyboard_led_set_brightness(struct led_classdev *cdev,
}

static enum led_brightness
-keyboard_led_get_brightness(struct led_classdev *cdev)
+keyboard_led_get_brightness_acpi(struct led_classdev *cdev)
{
unsigned long long brightness;
acpi_status status;
@@ -56,12 +83,10 @@ keyboard_led_get_brightness(struct led_classdev *cdev)
return brightness;
}

-static int keyboard_led_probe(struct platform_device *pdev)
+static int keyboard_led_init_acpi(struct platform_device *pdev)
{
- struct led_classdev *cdev;
acpi_handle handle;
acpi_status status;
- int error;

/* Look for the keyboard LED ACPI Device */
status = acpi_get_handle(ACPI_ROOT_OBJECT,
@@ -73,15 +98,44 @@ static int keyboard_led_probe(struct platform_device *pdev)
return -ENXIO;
}

+ return 0;
+}
+
+static const struct keyboard_led_drvdata keyboard_led_drvdata_acpi = {
+ .init = keyboard_led_init_acpi,
+ .brightness_set = keyboard_led_set_brightness_acpi,
+ .brightness_get = keyboard_led_get_brightness_acpi,
+ .max_brightness = ACPI_KEYBOARD_BACKLIGHT_MAX,
+};
+
+#endif /* CONFIG_ACPI */
+
+static int keyboard_led_probe(struct platform_device *pdev)
+{
+ struct led_classdev *cdev;
+ const struct keyboard_led_drvdata *drvdata;
+ int error;
+
+ drvdata = acpi_device_get_match_data(&pdev->dev);
+ if (!drvdata)
+ return -EINVAL;
+
+ if (drvdata->init) {
+ error = drvdata->init(pdev);
+ if (error)
+ return error;
+ }
+
cdev = devm_kzalloc(&pdev->dev, sizeof(*cdev), GFP_KERNEL);
if (!cdev)
return -ENOMEM;

cdev->name = "chromeos::kbd_backlight";
- cdev->max_brightness = ACPI_KEYBOARD_BACKLIGHT_MAX;
cdev->flags |= LED_CORE_SUSPENDRESUME;
- cdev->brightness_set = keyboard_led_set_brightness;
- cdev->brightness_get = keyboard_led_get_brightness;
+ cdev->max_brightness = drvdata->max_brightness;
+ cdev->brightness_set = drvdata->brightness_set;
+ cdev->brightness_set_blocking = drvdata->brightness_set_blocking;
+ cdev->brightness_get = drvdata->brightness_get;

error = devm_led_classdev_register(&pdev->dev, cdev);
if (error)
@@ -90,16 +144,18 @@ static int keyboard_led_probe(struct platform_device *pdev)
return 0;
}

-static const struct acpi_device_id keyboard_led_id[] = {
- { "GOOG0002", 0 },
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id keyboard_led_acpi_match[] = {
+ { "GOOG0002", (kernel_ulong_t)&keyboard_led_drvdata_acpi },
{ }
};
-MODULE_DEVICE_TABLE(acpi, keyboard_led_id);
+MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match);
+#endif

static struct platform_driver keyboard_led_driver = {
.driver = {
.name = "chromeos-keyboard-leds",
- .acpi_match_table = ACPI_PTR(keyboard_led_id),
+ .acpi_match_table = ACPI_PTR(keyboard_led_acpi_match),
},
.probe = keyboard_led_probe,
};
--
2.36.1.124.g0e6072fb45-goog