/*
 * USB LED Driver for NVIDIA Shield
 *
 * Copyright (c) 2013-2014, NVIDIA Corporation. All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/slab.h>
#include <linux/reboot.h>
#include <linux/notifier.h>

#define DRIVER_AUTHOR "Jun Yan, juyan@nvidia.com"
#define DRIVER_DESC "NVIDIA Shield USB LED Driver"

#define INTF_CLASS 0xFF
#define INTF_SUBCLASS 0x01
#define INTF_PROTOCOL 0x01

#define LED_STATE_NORMAL	"normal"
#define LED_STATE_BLINK		"blink"
#define LED_STATE_BREATHE	"breathe"
#define LED_STATE_OFF		"off"
#define LED_STATE_UNKNOW	"unknow"

#define LED_STATE_MAXCHAR 8
#define LED_NUM 2

#define UC_COMM_ON		0x10
#define UC_COMM_BLINK	0x11
#define UC_COMM_BREATHE	0x12
#define UC_COMM_OFF		0x13

#define UC_COMM_PWR_LED 0x00
#define UC_COMM_TCH_LED 0x80

#define VID 0x0955
#define PID 0x7205

#define LED_NVBUTTON 0
#define LED_TOUCH 1

struct nvshield_led *g_dev;

static const struct usb_device_id nvshield_table[] = {
	{ USB_DEVICE_AND_INTERFACE_INFO(VID, PID,
			INTF_CLASS, INTF_SUBCLASS, INTF_PROTOCOL) },
	{}
};
MODULE_DEVICE_TABLE(usb, nvshield_table);

enum led_state {
	LED_NORMAL,
	LED_BLINK,
	LED_BREATHE,
	LED_OFF,
};


struct nvshield_led {
	struct usb_device	*udev;
	unsigned char		brightness[LED_NUM];
	enum led_state		state[LED_NUM];
};

static unsigned char brightness_table[256] = {
	0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2,
	3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 9,
	9, 9, 10, 10, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 16, 16,
	17, 17, 18, 18, 19, 19, 20, 21, 21, 22, 23, 23, 24, 24, 25, 26, 27,
	27, 28, 29, 29, 30, 31, 32, 32, 33, 34, 35, 35, 36, 37, 38, 39, 39,
	40, 41, 42, 43, 44, 45, 46, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,
	56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72,
	73, 75, 76, 77, 78, 79, 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92,
	93, 94, 96, 97, 98, 99, 100, 102, 103, 104, 106, 107, 108, 109, 111,
	112, 113, 115, 116, 117, 118, 120, 121, 122, 124, 125, 127, 128, 129,
	131, 132, 133, 135, 136, 138, 139, 140, 142, 143, 145, 146, 147, 149,
	150, 152, 153, 155, 156, 157, 159, 160, 162, 163, 165, 166, 168, 169,
	171, 172, 174, 175, 177, 178, 180, 181, 183, 184, 186, 187, 189, 190,
	192, 193, 195, 196, 198, 199, 201, 202, 204, 205, 207, 208, 210, 212,
	213, 215, 216, 218, 219, 221, 222, 224, 226, 227, 229, 230, 232, 233,
	235, 236, 238, 240, 241, 243, 244, 246, 247, 249, 251, 252, 254, 255
};

static void send_command(struct nvshield_led *led, int led_id)
{
	int retval = 0;
	unsigned char state;
	unsigned char brightness;

	if (led->state[led_id] == LED_BREATHE)
		state = UC_COMM_BREATHE;
	else if (led->state[led_id] == LED_BLINK)
		state = UC_COMM_BLINK;
	else if (led->state[led_id] == LED_NORMAL)
		state = UC_COMM_ON;
	else if (led->state[led_id] == LED_OFF)
		state = UC_COMM_OFF;
	else
		return;

	brightness = led->brightness[led_id];
	if (led_id == LED_TOUCH)
		state |= UC_COMM_TCH_LED;
	else
		brightness = brightness_table[(unsigned int)brightness];

	retval = usb_control_msg(led->udev,
			usb_sndctrlpipe(led->udev, 0),
			0x00,
			0x42,
			cpu_to_le16(brightness),
			cpu_to_le16(state),
			NULL,
			0,
			2000);
}


static ssize_t show_brightness(struct device *dev,
		struct device_attribute *attr,
		char *buf)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct nvshield_led *led = usb_get_intfdata(intf);

	return sprintf(buf, "%d\n", led->brightness[LED_NVBUTTON]);
}

static ssize_t show_brightness2(struct device *dev,
		struct device_attribute *attr,
		char *buf)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct nvshield_led *led = usb_get_intfdata(intf);

	return sprintf(buf, "%d\n", led->brightness[LED_TOUCH]);
}

static ssize_t set_brightness(struct device *dev,
		struct device_attribute *attr,
		const char *buf, size_t count)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct nvshield_led *led = usb_get_intfdata(intf);
	unsigned long brightness_val;

	if (!kstrtoul(buf, 10, &brightness_val)) {
		led->brightness[LED_NVBUTTON] = (unsigned char)brightness_val;
		send_command(led, LED_NVBUTTON);
	}
	return count;
}

static ssize_t set_brightness2(struct device *dev,
		struct device_attribute *attr,
		const char *buf, size_t count)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct nvshield_led *led = usb_get_intfdata(intf);
	unsigned long brightness_val;

	if (!kstrtoul(buf, 10, &brightness_val)) {
		led->brightness[LED_TOUCH] = (unsigned char)brightness_val;
		send_command(led, LED_TOUCH);
	}
	return count;
}

static ssize_t show_ledstate(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct nvshield_led *led = usb_get_intfdata(intf);

	switch (led->state[LED_NVBUTTON]) {
	case LED_NORMAL:
		return sprintf(buf, "%s\n", LED_STATE_NORMAL);
	case LED_BLINK:
		return sprintf(buf, "%s\n", LED_STATE_BLINK);
	case LED_BREATHE:
		return sprintf(buf, "%s\n", LED_STATE_BREATHE);
	case LED_OFF:
		return sprintf(buf, "%s\n", LED_STATE_OFF);
	default:
		return sprintf(buf, LED_STATE_UNKNOW);
	}
}

static ssize_t set_ledstate(struct device *dev, struct device_attribute *attr,
		const char *buf, size_t count)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct nvshield_led *led = usb_get_intfdata(intf);
	char ledstate_name[LED_STATE_MAXCHAR];
	size_t len;

	ledstate_name[sizeof(ledstate_name) - 1] = '\0';
	strncpy(ledstate_name, buf, sizeof(ledstate_name) - 1);
	len = strlen(ledstate_name);

	if (len && ledstate_name[len - 1] == '\n')
		ledstate_name[len - 1] = '\0';

	if (!strcmp(ledstate_name, LED_STATE_NORMAL))
		led->state[LED_NVBUTTON] = LED_NORMAL;
	else if (!strcmp(ledstate_name, LED_STATE_BLINK))
		led->state[LED_NVBUTTON] = LED_BLINK;
	else if (!strcmp(ledstate_name, LED_STATE_BREATHE))
		led->state[LED_NVBUTTON] = LED_BREATHE;
	else if (!strcmp(ledstate_name, LED_STATE_OFF))
		led->state[LED_NVBUTTON] = LED_OFF;
	else
		return count;

	send_command(led, LED_NVBUTTON);
	return count;
}

static DEVICE_ATTR(brightness, S_IRUGO | S_IWUSR,
		show_brightness, set_brightness);
static DEVICE_ATTR(state, S_IRUGO | S_IWUSR,
		show_ledstate, set_ledstate);
static DEVICE_ATTR(brightness2, S_IRUGO | S_IWUSR,
		show_brightness2, set_brightness2);

static int nvshieldled_reboot_callback(struct notifier_block *nb,
		unsigned long code,
		void *unused) {
	if (!g_dev)
		return NOTIFY_DONE;
	g_dev->state[LED_NVBUTTON] = LED_NORMAL;
	send_command(g_dev, LED_NVBUTTON);
	return NOTIFY_DONE;
}

static struct notifier_block nvshieldled_notifier = {
	.notifier_call = nvshieldled_reboot_callback,
};

static int nvshieldled_probe(struct usb_interface *interface,
		const struct usb_device_id *id)
{
	struct usb_device *udev = interface_to_usbdev(interface);
	struct nvshield_led *dev = NULL;
	int retval = -ENOMEM;

	dev = kzalloc(sizeof(struct nvshield_led), GFP_KERNEL);
	if (dev == NULL) {
		dev_err(&interface->dev, "out of memory\n");
		goto error_mem;
	}

	dev->udev = usb_get_dev(udev);
	dev->state[LED_NVBUTTON] = LED_NORMAL;
	dev->brightness[LED_NVBUTTON] = 255;
	dev->state[LED_TOUCH] = LED_NORMAL;
	dev->brightness[LED_TOUCH] = 255;

	usb_set_intfdata(interface, dev);
	g_dev = dev;

	retval = device_create_file(&interface->dev, &dev_attr_brightness);
	if (retval)
		goto error;
	retval = device_create_file(&interface->dev, &dev_attr_state);
	if (retval)
		goto error2;
	retval = device_create_file(&interface->dev, &dev_attr_brightness2);
	if (retval)
		goto error3;
	dev_info(&interface->dev, "Nvidia Shield LED attached\n");

	retval = register_reboot_notifier(&nvshieldled_notifier);
	if (retval)
		goto error4;
	return 0;

error4:
	device_remove_file(&interface->dev, &dev_attr_brightness2);
error3:
	device_remove_file(&interface->dev, &dev_attr_brightness);
error2:
	device_remove_file(&interface->dev, &dev_attr_state);
error:
	usb_set_intfdata(interface, NULL);
	usb_put_dev(dev->udev);
	kfree(dev);
error_mem:
	return retval;
}

static void nvshieldled_disconnect(struct usb_interface *interface)
{
	struct nvshield_led *dev;

	dev = usb_get_intfdata(interface);

	unregister_reboot_notifier(&nvshieldled_notifier);
	device_remove_file(&interface->dev, &dev_attr_brightness);
	device_remove_file(&interface->dev, &dev_attr_state);
	device_remove_file(&interface->dev, &dev_attr_brightness2);

	usb_set_intfdata(interface, NULL);
	usb_put_dev(dev->udev);
	kfree(dev);
	dev_info(&interface->dev, "Nvidia Shield LED disconnected\n");
}

static int nvshieldled_suspend(struct usb_interface *interface,
		pm_message_t notused)
{
	return 0;
}

static int nvshieldled_resume(struct usb_interface *interface)
{
	return 0;
}

static struct usb_driver shieldled_driver = {
	.name =		"nvshieldled",
	.probe =	nvshieldled_probe,
	.disconnect = nvshieldled_disconnect,
	.suspend =	nvshieldled_suspend,
	.resume =	nvshieldled_resume,
	.id_table = nvshield_table,
};

module_usb_driver(shieldled_driver);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");