// SPDX-License-Identifier: GPL-2.0+ // Keyboard backlight LED driver for ChromeOS // // Copyright (C) 2012 Google, Inc. #include #include #include #include #include #include #include #include #include #include #include #include #include #include struct keyboard_led { struct led_classdev cdev; struct cros_ec_device *ec; }; /** * 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; }; #define KEYBOARD_BACKLIGHT_MAX 100 #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" #define ACPI_KEYBOARD_BACKLIGHT_WRITE ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBCM" static void keyboard_led_set_brightness_acpi(struct led_classdev *cdev, enum led_brightness brightness) { union acpi_object param; struct acpi_object_list input; acpi_status status; param.type = ACPI_TYPE_INTEGER; param.integer.value = brightness; input.count = 1; input.pointer = ¶m; status = acpi_evaluate_object(NULL, ACPI_KEYBOARD_BACKLIGHT_WRITE, &input, NULL); if (ACPI_FAILURE(status)) dev_err(cdev->dev, "Error setting keyboard LED value: %d\n", status); } static enum led_brightness keyboard_led_get_brightness_acpi(struct led_classdev *cdev) { unsigned long long brightness; acpi_status status; status = acpi_evaluate_integer(NULL, ACPI_KEYBOARD_BACKLIGHT_READ, NULL, &brightness); if (ACPI_FAILURE(status)) { dev_err(cdev->dev, "Error getting keyboard LED value: %d\n", status); return -EIO; } return brightness; } static int keyboard_led_init_acpi(struct platform_device *pdev) { acpi_handle handle; acpi_status status; /* Look for the keyboard LED ACPI Device */ status = acpi_get_handle(ACPI_ROOT_OBJECT, ACPI_KEYBOARD_BACKLIGHT_DEVICE, &handle); if (ACPI_FAILURE(status)) { dev_err(&pdev->dev, "Unable to find ACPI device %s: %d\n", ACPI_KEYBOARD_BACKLIGHT_DEVICE, status); 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 = KEYBOARD_BACKLIGHT_MAX, }; #endif /* CONFIG_ACPI */ #if IS_ENABLED(CONFIG_CROS_EC) static int keyboard_led_set_brightness_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 *keyboard_led = container_of(cdev, struct keyboard_led, cdev); memset(&buf, 0, sizeof(buf)); msg->command = EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT; msg->outsize = sizeof(*params); params->percent = brightness; return cros_ec_cmd_xfer_status(keyboard_led->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 *keyboard_led = container_of(cdev, struct keyboard_led, cdev); int ret; memset(&buf, 0, sizeof(buf)); msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT; msg->insize = sizeof(*resp); ret = cros_ec_cmd_xfer_status(keyboard_led->ec, msg); if (ret < 0) return ret; return resp->percent; } static int keyboard_led_init_ec_pwm(struct platform_device *pdev) { struct keyboard_led *keyboard_led = platform_get_drvdata(pdev); keyboard_led->ec = dev_get_drvdata(pdev->dev.parent); if (!keyboard_led->ec) { dev_err(&pdev->dev, "no parent EC device\n"); return -EINVAL; } return 0; } static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = { .init = keyboard_led_init_ec_pwm, .brightness_set_blocking = keyboard_led_set_brightness_ec_pwm, .brightness_get = keyboard_led_get_brightness_ec_pwm, .max_brightness = KEYBOARD_BACKLIGHT_MAX, }; #else /* IS_ENABLED(CONFIG_CROS_EC) */ static const __maybe_unused struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm = {}; #endif /* IS_ENABLED(CONFIG_CROS_EC) */ static int keyboard_led_probe(struct platform_device *pdev) { const struct keyboard_led_drvdata *drvdata; struct keyboard_led *keyboard_led; int error; drvdata = device_get_match_data(&pdev->dev); if (!drvdata) return -EINVAL; keyboard_led = devm_kzalloc(&pdev->dev, sizeof(*keyboard_led), GFP_KERNEL); if (!keyboard_led) return -ENOMEM; platform_set_drvdata(pdev, keyboard_led); if (drvdata->init) { error = drvdata->init(pdev); if (error) return error; } keyboard_led->cdev.name = "chromeos::kbd_backlight"; keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME; keyboard_led->cdev.max_brightness = drvdata->max_brightness; keyboard_led->cdev.brightness_set = drvdata->brightness_set; keyboard_led->cdev.brightness_set_blocking = drvdata->brightness_set_blocking; keyboard_led->cdev.brightness_get = drvdata->brightness_get; error = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev); if (error) return error; return 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_acpi_match); #endif #ifdef CONFIG_OF static const struct of_device_id keyboard_led_of_match[] = { { .compatible = "google,cros-kbd-led-backlight", .data = &keyboard_led_drvdata_ec_pwm, }, {} }; MODULE_DEVICE_TABLE(of, keyboard_led_of_match); #endif static const struct platform_device_id keyboard_led_id[] = { { "cros-keyboard-leds", 0 }, {} }; MODULE_DEVICE_TABLE(platform, keyboard_led_id); static struct platform_driver keyboard_led_driver = { .driver = { .name = "cros-keyboard-leds", .acpi_match_table = ACPI_PTR(keyboard_led_acpi_match), .of_match_table = of_match_ptr(keyboard_led_of_match), }, .probe = keyboard_led_probe, .id_table = keyboard_led_id, }; module_platform_driver(keyboard_led_driver); MODULE_AUTHOR("Simon Que "); MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver"); MODULE_LICENSE("GPL");