// SPDX-License-Identifier: GPL-2.0+
// Keyboard backlight LED driver for ChromeOS
//
// Copyright (C) 2012 Google, Inc.

#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/mfd/core.h>
#include <linux/mod_devicetable.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 {
        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 = &param;

        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_MFD_CROS_EC_DEV)
static int keyboard_led_init_ec_pwm_mfd(struct platform_device *pdev)
{
        struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
        struct cros_ec_device *cros_ec = ec_dev->ec_dev;
        struct keyboard_led *keyboard_led = platform_get_drvdata(pdev);

        keyboard_led->ec = cros_ec;

        return 0;
}

static int
keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev,
                                   enum led_brightness brightness)
{
        DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
                        sizeof(struct ec_params_pwm_set_keyboard_backlight));
        struct ec_params_pwm_set_keyboard_backlight *params =
                        (struct ec_params_pwm_set_keyboard_backlight *)msg->data;
        struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);

        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)
{
        DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
                        sizeof(struct ec_response_pwm_get_keyboard_backlight));
        struct ec_response_pwm_get_keyboard_backlight *resp =
                        (struct ec_response_pwm_get_keyboard_backlight *)msg->data;
        struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
        int ret;

        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 const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {
        .init = keyboard_led_init_ec_pwm_mfd,
        .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_MFD_CROS_EC_DEV) */

static const struct keyboard_led_drvdata keyboard_led_drvdata_ec_pwm_mfd = {};

#endif /* IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) */

static int keyboard_led_is_mfd_device(struct platform_device *pdev)
{
        return IS_ENABLED(CONFIG_MFD_CROS_EC_DEV) && mfd_get_cell(pdev);
}

static int keyboard_led_probe(struct platform_device *pdev)
{
        const struct keyboard_led_drvdata *drvdata;
        struct keyboard_led *keyboard_led;
        int err;

        if (keyboard_led_is_mfd_device(pdev))
                drvdata = &keyboard_led_drvdata_ec_pwm_mfd;
        else
                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) {
                err = drvdata->init(pdev);
                if (err)
                        return err;
        }

        keyboard_led->cdev.name = "chromeos::kbd_backlight";
        keyboard_led->cdev.flags |= LED_CORE_SUSPENDRESUME | LED_REJECT_NAME_CONFLICT;
        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;

        err = devm_led_classdev_register(&pdev->dev, &keyboard_led->cdev);
        if (err == -EEXIST) /* Already bound via other mechanism */
                return -ENODEV;
        return err;
}

#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

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),
        },
        .probe          = keyboard_led_probe,
        .id_table       = keyboard_led_id,
};
module_platform_driver(keyboard_led_driver);

MODULE_AUTHOR("Simon Que <sque@chromium.org>");
MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver");
MODULE_LICENSE("GPL");