/*
 * ThingM blink(1) USB RGB LED driver
 *
 * Copyright 2013 Savoir-faire Linux Inc.
 *      Vivien Didelot <vivien.didelot@savoirfairelinux.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, version 2.
 */

#include <linux/hid.h>
#include <linux/leds.h>
#include <linux/module.h>

#include "hid-ids.h"

#define BLINK1_CMD_SIZE         9

#define blink1_rgb_to_r(rgb)    ((rgb & 0xFF0000) >> 16)
#define blink1_rgb_to_g(rgb)    ((rgb & 0x00FF00) >> 8)
#define blink1_rgb_to_b(rgb)    ((rgb & 0x0000FF) >> 0)

/**
 * struct blink1_data - blink(1) device specific data
 * @hdev:               HID device.
 * @led_cdev:           LED class instance.
 * @rgb:                8-bit per channel RGB notation.
 * @fade:               fade time in hundredths of a second.
 * @brightness:         brightness coefficient.
 * @play:               play/pause in-memory patterns.
 */
struct blink1_data {
        struct hid_device *hdev;
        struct led_classdev led_cdev;
        u32 rgb;
        u16 fade;
        u8 brightness;
        bool play;
};

static int blink1_send_command(struct blink1_data *data,
                u8 buf[BLINK1_CMD_SIZE])
{
        int ret;

        hid_dbg(data->hdev, "command: %d%c%.2x%.2x%.2x%.2x%.2x%.2x%.2x\n",
                        buf[0], buf[1], buf[2], buf[3], buf[4],
                        buf[5], buf[6], buf[7], buf[8]);

        ret = data->hdev->hid_output_raw_report(data->hdev, buf,
                        BLINK1_CMD_SIZE, HID_FEATURE_REPORT);

        return ret < 0 ? ret : 0;
}

static int blink1_update_color(struct blink1_data *data)
{
        u8 buf[BLINK1_CMD_SIZE] = { 1, 'n', 0, 0, 0, 0, 0, 0, 0 };

        if (data->brightness) {
                unsigned int coef = DIV_ROUND_CLOSEST(255, data->brightness);

                buf[2] = DIV_ROUND_CLOSEST(blink1_rgb_to_r(data->rgb), coef);
                buf[3] = DIV_ROUND_CLOSEST(blink1_rgb_to_g(data->rgb), coef);
                buf[4] = DIV_ROUND_CLOSEST(blink1_rgb_to_b(data->rgb), coef);
        }

        if (data->fade) {
                buf[1] = 'c';
                buf[5] = (data->fade & 0xFF00) >> 8;
                buf[6] = (data->fade & 0x00FF);
        }

        return blink1_send_command(data, buf);
}

static void blink1_led_set(struct led_classdev *led_cdev,
                enum led_brightness brightness)
{
        struct blink1_data *data = dev_get_drvdata(led_cdev->dev->parent);

        data->brightness = brightness;
        if (blink1_update_color(data))
                hid_err(data->hdev, "failed to update color\n");
}

static enum led_brightness blink1_led_get(struct led_classdev *led_cdev)
{
        struct blink1_data *data = dev_get_drvdata(led_cdev->dev->parent);

        return data->brightness;
}

static ssize_t blink1_show_rgb(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct blink1_data *data = dev_get_drvdata(dev->parent);

        return sprintf(buf, "%.6X\n", data->rgb);
}

static ssize_t blink1_store_rgb(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct blink1_data *data = dev_get_drvdata(dev->parent);
        long unsigned int rgb;
        int ret;

        ret = kstrtoul(buf, 16, &rgb);
        if (ret)
                return ret;

        /* RGB triplet notation is 24-bit hexadecimal */
        if (rgb > 0xFFFFFF)
                return -EINVAL;

        data->rgb = rgb;
        ret = blink1_update_color(data);

        return ret ? ret : count;
}

static DEVICE_ATTR(rgb, S_IRUGO | S_IWUSR, blink1_show_rgb, blink1_store_rgb);

static ssize_t blink1_show_fade(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct blink1_data *data = dev_get_drvdata(dev->parent);

        return sprintf(buf, "%d\n", data->fade * 10);
}

static ssize_t blink1_store_fade(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct blink1_data *data = dev_get_drvdata(dev->parent);
        long unsigned int fade;
        int ret;

        ret = kstrtoul(buf, 10, &fade);
        if (ret)
                return ret;

        /* blink(1) accepts 16-bit fade time, number of 10ms ticks */
        fade = DIV_ROUND_CLOSEST(fade, 10);
        if (fade > 65535)
                return -EINVAL;

        data->fade = fade;

        return count;
}

static DEVICE_ATTR(fade, S_IRUGO | S_IWUSR,
                blink1_show_fade, blink1_store_fade);

static ssize_t blink1_show_play(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct blink1_data *data = dev_get_drvdata(dev->parent);

        return sprintf(buf, "%d\n", data->play);
}

static ssize_t blink1_store_play(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct blink1_data *data = dev_get_drvdata(dev->parent);
        u8 cmd[BLINK1_CMD_SIZE] = { 1, 'p', 0, 0, 0, 0, 0, 0, 0 };
        long unsigned int play;
        int ret;

        ret = kstrtoul(buf, 10, &play);
        if (ret)
                return ret;

        data->play = !!play;
        cmd[2] = data->play;
        ret = blink1_send_command(data, cmd);

        return ret ? ret : count;
}

static DEVICE_ATTR(play, S_IRUGO | S_IWUSR,
                blink1_show_play, blink1_store_play);

static const struct attribute_group blink1_sysfs_group = {
        .attrs = (struct attribute *[]) {
                &dev_attr_rgb.attr,
                &dev_attr_fade.attr,
                &dev_attr_play.attr,
                NULL
        },
};

static int thingm_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
        struct blink1_data *data;
        struct led_classdev *led;
        char led_name[13];
        int ret;

        data = devm_kzalloc(&hdev->dev, sizeof(struct blink1_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        hid_set_drvdata(hdev, data);
        data->hdev = hdev;
        data->rgb = 0xFFFFFF; /* set a default white color */

        ret = hid_parse(hdev);
        if (ret)
                goto error;

        ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
        if (ret)
                goto error;

        /* blink(1) serial numbers range is 0x1A001000 to 0x1A002FFF */
        led = &data->led_cdev;
        snprintf(led_name, sizeof(led_name), "blink1::%s", hdev->uniq + 4);
        led->name = led_name;
        led->brightness_set = blink1_led_set;
        led->brightness_get = blink1_led_get;
        ret = led_classdev_register(&hdev->dev, led);
        if (ret)
                goto stop;

        ret = sysfs_create_group(&led->dev->kobj, &blink1_sysfs_group);
        if (ret)
                goto remove_led;

        return 0;

remove_led:
        led_classdev_unregister(led);
stop:
        hid_hw_stop(hdev);
error:
        return ret;
}

static void thingm_remove(struct hid_device *hdev)
{
        struct blink1_data *data = hid_get_drvdata(hdev);
        struct led_classdev *led = &data->led_cdev;

        sysfs_remove_group(&led->dev->kobj, &blink1_sysfs_group);
        led_classdev_unregister(led);
        hid_hw_stop(hdev);
}

static const struct hid_device_id thingm_table[] = {
        { HID_USB_DEVICE(USB_VENDOR_ID_THINGM, USB_DEVICE_ID_BLINK1) },
        { }
};
MODULE_DEVICE_TABLE(hid, thingm_table);

static struct hid_driver thingm_driver = {
        .name = "thingm",
        .probe = thingm_probe,
        .remove = thingm_remove,
        .id_table = thingm_table,
};

module_hid_driver(thingm_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Vivien Didelot <vivien.didelot@savoirfairelinux.com>");
MODULE_DESCRIPTION("ThingM blink(1) USB RGB LED driver");