[PATCH v3 5/5] platform/chrome: cros_kbd_led_backlight: support EC PWM backend

Tzung-Bi Shih
2022-03-21T08:57:17Z

EC PWM backend uses EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT and
EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT for setting and getting the brightness
respectively.

Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
---
Changes from v2:
- Turn CROS_KBD_LED_BACKLIGHT_EC_PWM to boolean.
- Use #ifdef for boolean CROS_KBD_LED_BACKLIGHT_EC_PWM.

Changes from v1:
- Update email address accordingly.

drivers/platform/chrome/Kconfig | 6 +
.../platform/chrome/cros_kbd_led_backlight.c | 126 +++++++++++++++---
2 files changed, 117 insertions(+), 15 deletions(-)

diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 3f74679a556c..e02789d7c0d4 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -142,6 +142,12 @@ config CROS_KBD_LED_BACKLIGHT_ACPI
help
ChromeOS keyboard backlight ACPI backend.

+config CROS_KBD_LED_BACKLIGHT_EC_PWM
+ bool "ChromeOS keyboard backlight EC PWM backend"
+ depends on CROS_EC && CROS_KBD_LED_BACKLIGHT
+ help
+ ChromeOS keyboard backlight EC PWM backend.
+
config CROS_EC_CHARDEV
tristate "ChromeOS EC miscdevice"
depends on MFD_CROS_EC_DEV
diff --git a/drivers/platform/chrome/cros_kbd_led_backlight.c b/drivers/platform/chrome/cros_kbd_led_backlight.c
index 5cbe27cb4610..8c35dd2fa607 100644
--- a/drivers/platform/chrome/cros_kbd_led_backlight.c
+++ b/drivers/platform/chrome/cros_kbd_led_backlight.c
@@ -11,10 +11,17 @@
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/slab.h>

+struct keyboard_led_private {
+ struct led_classdev cdev;
+ struct cros_ec_device *ec;
+};
+
/**
* struct keyboard_led_drvdata - keyboard LED driver data.
* @init: Init function.
@@ -40,6 +47,8 @@ struct keyboard_led_drvdata {
enum led_brightness max_brightness;
};

+#define KEYBOARD_BACKLIGHT_MAX 100
+
#ifdef CONFIG_CROS_KBD_LED_BACKLIGHT_ACPI

/* Keyboard LED ACPI Device must be defined in firmware */
@@ -47,8 +56,6 @@ struct keyboard_led_drvdata {
#define ACPI_KEYBOARD_BACKLIGHT_READ ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBQC"
#define ACPI_KEYBOARD_BACKLIGHT_WRITE ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBCM"

-#define ACPI_KEYBOARD_BACKLIGHT_MAX 100
-
static void keyboard_led_set_brightness_acpi(struct led_classdev *cdev,
enum led_brightness brightness)
{
@@ -107,7 +114,7 @@ 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,
+ .max_brightness = KEYBOARD_BACKLIGHT_MAX,
};

#else /* CONFIG_CROS_KBD_LED_BACKLIGHT_ACPI */
@@ -123,34 +130,122 @@ static const struct keyboard_led_drvdata keyboard_led_drvdata_acpi = {

#endif /* CONFIG_CROS_KBD_LED_BACKLIGHT_ACPI */

+#ifdef CONFIG_CROS_KBD_LED_BACKLIGHT_EC_PWM
+
+static int
+keyboard_led_set_brightness_blocking_ec_pwm(struct led_classdev *cdev,
+ enum led_brightness brightness)
+{
+ struct {
+ struct cros_ec_command msg;
+ struct ec_params_pwm_set_keyboard_backlight params;
+ } __packed buf;
+ struct ec_params_pwm_set_keyboard_backlight *params = &buf.params;
+ struct cros_ec_command *msg = &buf.msg;
+ struct keyboard_led_private *private =
+ container_of(cdev, struct keyboard_led_private, cdev);
+
+ memset(&buf, 0, sizeof(buf));
+
+ msg->version = 0;
+ msg->command = EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT;
+ msg->insize = 0;
+ msg->outsize = sizeof(*params);
+
+ params->percent = brightness;
+
+ return cros_ec_cmd_xfer_status(private->ec, msg);
+}
+
+static enum led_brightness
+keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev)
+{
+ struct {
+ struct cros_ec_command msg;
+ struct ec_response_pwm_get_keyboard_backlight resp;
+ } __packed buf;
+ struct ec_response_pwm_get_keyboard_backlight *resp = &buf.resp;
+ struct cros_ec_command *msg = &buf.msg;
+ struct keyboard_led_private *private =
+ container_of(cdev, struct keyboard_led_private, cdev);
+ int ret;
+
+ memset(&buf, 0, sizeof(buf));
+
+ msg->version = 0;
+ msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT;
+ msg->insize = sizeof(*resp);
+ msg->outsize = 0;
+
+ ret = cros_ec_cmd_xfer_status(private->ec, msg);
+ if (ret < 0)
+ return ret;
+
+ return resp->percent;
+}
+
+static int keyboard_led_init_ec_pwm(struct platform_device *pdev)
+{
+ struct keyboard_led_private *private = platform_get_drvdata(pdev);
+
+ private->ec = dev_get_drvdata(pdev->dev.parent);
+ if (!private->ec) {
+ dev_err(&pdev->dev, "no parent EC device\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {
+ .init = keyboard_led_init_ec_pwm,
+ .brightness_set_blocking = keyboard_led_set_brightness_blocking_ec_pwm,
+ .brightness_get = keyboard_led_get_brightness_ec_pwm,
+ .max_brightness = KEYBOARD_BACKLIGHT_MAX,
+};
+
+#else /* CONFIG_CROS_KBD_LED_BACKLIGHT_EC_PWM */
+
+static int keyboard_led_init_ec_pwm_null(struct platform_device *pdev)
+{
+ return -EOPNOTSUPP;
+}
+
+static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {
+ .init = keyboard_led_init_ec_pwm_null,
+};
+
+#endif /* CONFIG_CROS_KBD_LED_BACKLIGHT_EC_PWM */
+
static int keyboard_led_probe(struct platform_device *pdev)
{
- struct led_classdev *cdev;
const struct keyboard_led_drvdata *drvdata;
+ struct keyboard_led_private *private;
int error;

drvdata = device_get_match_data(&pdev->dev);
if (!drvdata)
return -EINVAL;

+ private = devm_kzalloc(&pdev->dev, sizeof(*private), GFP_KERNEL);
+ if (!private)
+ return -ENOMEM;
+ platform_set_drvdata(pdev, private);
+
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->flags |= LED_CORE_SUSPENDRESUME;
- 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;
+ private->cdev.name = "chromeos::kbd_backlight";
+ private->cdev.flags |= LED_CORE_SUSPENDRESUME;
+ private->cdev.max_brightness = drvdata->max_brightness;
+ private->cdev.brightness_set = drvdata->brightness_set;
+ private->cdev.brightness_set_blocking = drvdata->brightness_set_blocking;
+ private->cdev.brightness_get = drvdata->brightness_get;

- error = devm_led_classdev_register(&pdev->dev, cdev);
+ error = devm_led_classdev_register(&pdev->dev, &private->cdev);
if (error)
return error;

@@ -169,6 +264,7 @@ MODULE_DEVICE_TABLE(acpi, keyboard_led_acpi_match);
static const struct of_device_id keyboard_led_of_match[] = {
{
.compatible = "google,cros-kbd-led-backlight",
+ .data = &keyboard_led_drvdata_ec_pwm,
},
{}
};
--
2.35.1.894.gb6a874cedc-goog