/*
   * 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
  ",
  			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
  ");
  }
  
  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
  ", 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
  ", 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
  ", 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");