/*
 * Linux V4L2 radio driver for the Griffin radioSHARK USB radio receiver
 *
 * Note the radioSHARK offers the audio through a regular USB audio device,
 * this driver only handles the tuning.
 *
 * The info necessary to drive the shark was taken from the small userspace
 * shark.c program by Michael Rolig, which he kindly placed in the Public
 * Domain.
 *
 * Copyright (c) 2012 Hans de Goede <hdegoede@redhat.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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/workqueue.h>
#include <media/v4l2-device.h>
#include <sound/tea575x-tuner.h>

/*
 * Version Information
 */
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_DESCRIPTION("Griffin radioSHARK, USB radio receiver driver");
MODULE_LICENSE("GPL");

#define SHARK_IN_EP		0x83
#define SHARK_OUT_EP		0x05

#define TEA575X_BIT_MONO	(1<<22)		/* 0 = stereo, 1 = mono */
#define TEA575X_BIT_BAND_MASK	(3<<20)
#define TEA575X_BIT_BAND_FM	(0<<20)

#define TB_LEN 6
#define DRV_NAME "radioshark"

#define v4l2_dev_to_shark(d) container_of(d, struct shark_device, v4l2_dev)

enum { BLUE_LED, BLUE_PULSE_LED, RED_LED, NO_LEDS };

static void shark_led_set_blue(struct led_classdev *led_cdev,
			       enum led_brightness value);
static void shark_led_set_blue_pulse(struct led_classdev *led_cdev,
				     enum led_brightness value);
static void shark_led_set_red(struct led_classdev *led_cdev,
			      enum led_brightness value);

static const struct led_classdev shark_led_templates[NO_LEDS] = {
	[BLUE_LED] = {
		.name		= "%s:blue:",
		.brightness	= LED_OFF,
		.max_brightness = 127,
		.brightness_set = shark_led_set_blue,
	},
	[BLUE_PULSE_LED] = {
		.name		= "%s:blue-pulse:",
		.brightness	= LED_OFF,
		.max_brightness = 255,
		.brightness_set = shark_led_set_blue_pulse,
	},
	[RED_LED] = {
		.name		= "%s:red:",
		.brightness	= LED_OFF,
		.max_brightness = 1,
		.brightness_set = shark_led_set_red,
	},
};

struct shark_device {
	struct usb_device *usbdev;
	struct v4l2_device v4l2_dev;
	struct snd_tea575x tea;

	struct work_struct led_work;
	struct led_classdev leds[NO_LEDS];
	char led_names[NO_LEDS][32];
	atomic_t brightness[NO_LEDS];
	unsigned long brightness_new;

	u8 *transfer_buffer;
	u32 last_val;
};

static atomic_t shark_instance = ATOMIC_INIT(0);

static void shark_write_val(struct snd_tea575x *tea, u32 val)
{
	struct shark_device *shark = tea->private_data;
	int i, res, actual_len;

	/* Avoid unnecessary (slow) USB transfers */
	if (shark->last_val == val)
		return;

	memset(shark->transfer_buffer, 0, TB_LEN);
	shark->transfer_buffer[0] = 0xc0; /* Write shift register command */
	for (i = 0; i < 4; i++)
		shark->transfer_buffer[i] |= (val >> (24 - i * 8)) & 0xff;

	res = usb_interrupt_msg(shark->usbdev,
				usb_sndintpipe(shark->usbdev, SHARK_OUT_EP),
				shark->transfer_buffer, TB_LEN,
				&actual_len, 1000);
	if (res >= 0)
		shark->last_val = val;
	else
		v4l2_err(&shark->v4l2_dev, "set-freq error: %d\n", res);
}

static u32 shark_read_val(struct snd_tea575x *tea)
{
	struct shark_device *shark = tea->private_data;
	int i, res, actual_len;
	u32 val = 0;

	memset(shark->transfer_buffer, 0, TB_LEN);
	shark->transfer_buffer[0] = 0x80;
	res = usb_interrupt_msg(shark->usbdev,
				usb_sndintpipe(shark->usbdev, SHARK_OUT_EP),
				shark->transfer_buffer, TB_LEN,
				&actual_len, 1000);
	if (res < 0) {
		v4l2_err(&shark->v4l2_dev, "request-status error: %d\n", res);
		return shark->last_val;
	}

	res = usb_interrupt_msg(shark->usbdev,
				usb_rcvintpipe(shark->usbdev, SHARK_IN_EP),
				shark->transfer_buffer, TB_LEN,
				&actual_len, 1000);
	if (res < 0) {
		v4l2_err(&shark->v4l2_dev, "get-status error: %d\n", res);
		return shark->last_val;
	}

	for (i = 0; i < 4; i++)
		val |= shark->transfer_buffer[i] << (24 - i * 8);

	shark->last_val = val;

	/*
	 * The shark does not allow actually reading the stereo / mono pin :(
	 * So assume that when we're tuned to an FM station and mono has not
	 * been requested, that we're receiving stereo.
	 */
	if (((val & TEA575X_BIT_BAND_MASK) == TEA575X_BIT_BAND_FM) &&
	    !(val & TEA575X_BIT_MONO))
		shark->tea.stereo = true;
	else
		shark->tea.stereo = false;

	return val;
}

static struct snd_tea575x_ops shark_tea_ops = {
	.write_val = shark_write_val,
	.read_val  = shark_read_val,
};

static void shark_led_work(struct work_struct *work)
{
	struct shark_device *shark =
		container_of(work, struct shark_device, led_work);
	int i, res, brightness, actual_len;

	/*
	 * We use the v4l2_dev lock and registered bit to ensure the device
	 * does not get unplugged and unreffed while we're running.
	 */
	mutex_lock(&shark->tea.mutex);
	if (!video_is_registered(&shark->tea.vd))
		goto leave;

	for (i = 0; i < 3; i++) {
		if (!test_and_clear_bit(i, &shark->brightness_new))
			continue;

		brightness = atomic_read(&shark->brightness[i]);
		memset(shark->transfer_buffer, 0, TB_LEN);
		if (i != RED_LED) {
			shark->transfer_buffer[0] = 0xA0 + i;
			shark->transfer_buffer[1] = brightness;
		} else
			shark->transfer_buffer[0] = brightness ? 0xA9 : 0xA8;
		res = usb_interrupt_msg(shark->usbdev,
					usb_sndintpipe(shark->usbdev, 0x05),
					shark->transfer_buffer, TB_LEN,
					&actual_len, 1000);
		if (res < 0)
			v4l2_err(&shark->v4l2_dev, "set LED %s error: %d\n",
				 shark->led_names[i], res);
	}
leave:
	mutex_unlock(&shark->tea.mutex);
}

static void shark_led_set_blue(struct led_classdev *led_cdev,
			       enum led_brightness value)
{
	struct shark_device *shark =
		container_of(led_cdev, struct shark_device, leds[BLUE_LED]);

	atomic_set(&shark->brightness[BLUE_LED], value);
	set_bit(BLUE_LED, &shark->brightness_new);
	schedule_work(&shark->led_work);
}

static void shark_led_set_blue_pulse(struct led_classdev *led_cdev,
				     enum led_brightness value)
{
	struct shark_device *shark = container_of(led_cdev,
				struct shark_device, leds[BLUE_PULSE_LED]);

	atomic_set(&shark->brightness[BLUE_PULSE_LED], 256 - value);
	set_bit(BLUE_PULSE_LED, &shark->brightness_new);
	schedule_work(&shark->led_work);
}

static void shark_led_set_red(struct led_classdev *led_cdev,
			      enum led_brightness value)
{
	struct shark_device *shark =
		container_of(led_cdev, struct shark_device, leds[RED_LED]);

	atomic_set(&shark->brightness[RED_LED], value);
	set_bit(RED_LED, &shark->brightness_new);
	schedule_work(&shark->led_work);
}

static void usb_shark_disconnect(struct usb_interface *intf)
{
	struct v4l2_device *v4l2_dev = usb_get_intfdata(intf);
	struct shark_device *shark = v4l2_dev_to_shark(v4l2_dev);
	int i;

	mutex_lock(&shark->tea.mutex);
	v4l2_device_disconnect(&shark->v4l2_dev);
	snd_tea575x_exit(&shark->tea);
	mutex_unlock(&shark->tea.mutex);

	for (i = 0; i < NO_LEDS; i++)
		led_classdev_unregister(&shark->leds[i]);

	v4l2_device_put(&shark->v4l2_dev);
}

static void usb_shark_release(struct v4l2_device *v4l2_dev)
{
	struct shark_device *shark = v4l2_dev_to_shark(v4l2_dev);

	cancel_work_sync(&shark->led_work);
	v4l2_device_unregister(&shark->v4l2_dev);
	kfree(shark->transfer_buffer);
	kfree(shark);
}

static int usb_shark_probe(struct usb_interface *intf,
			   const struct usb_device_id *id)
{
	struct shark_device *shark;
	int i, retval = -ENOMEM;

	shark = kzalloc(sizeof(struct shark_device), GFP_KERNEL);
	if (!shark)
		return retval;

	shark->transfer_buffer = kmalloc(TB_LEN, GFP_KERNEL);
	if (!shark->transfer_buffer)
		goto err_alloc_buffer;

	/*
	 * Work around a bug in usbhid/hid-core.c, where it leaves a dangling
	 * pointer in intfdata causing v4l2-device.c to not set it. Which
	 * results in usb_shark_disconnect() referencing the dangling pointer
	 *
	 * REMOVE (as soon as the above bug is fixed, patch submitted)
	 */
	usb_set_intfdata(intf, NULL);

	shark->v4l2_dev.release = usb_shark_release;
	v4l2_device_set_name(&shark->v4l2_dev, DRV_NAME, &shark_instance);
	retval = v4l2_device_register(&intf->dev, &shark->v4l2_dev);
	if (retval) {
		v4l2_err(&shark->v4l2_dev, "couldn't register v4l2_device\n");
		goto err_reg_dev;
	}

	shark->usbdev = interface_to_usbdev(intf);
	shark->tea.v4l2_dev = &shark->v4l2_dev;
	shark->tea.private_data = shark;
	shark->tea.radio_nr = -1;
	shark->tea.ops = &shark_tea_ops;
	shark->tea.cannot_mute = true;
	strlcpy(shark->tea.card, "Griffin radioSHARK",
		sizeof(shark->tea.card));
	usb_make_path(shark->usbdev, shark->tea.bus_info,
		sizeof(shark->tea.bus_info));

	retval = snd_tea575x_init(&shark->tea, THIS_MODULE);
	if (retval) {
		v4l2_err(&shark->v4l2_dev, "couldn't init tea5757\n");
		goto err_init_tea;
	}

	INIT_WORK(&shark->led_work, shark_led_work);
	for (i = 0; i < NO_LEDS; i++) {
		shark->leds[i] = shark_led_templates[i];
		snprintf(shark->led_names[i], sizeof(shark->led_names[0]),
			 shark->leds[i].name, shark->v4l2_dev.name);
		shark->leds[i].name = shark->led_names[i];
		/*
		 * We don't fail the probe if we fail to register the leds,
		 * because once we've called snd_tea575x_init, the /dev/radio0
		 * node may be opened from userspace holding a reference to us!
		 *
		 * Note we cannot register the leds first instead as
		 * shark_led_work depends on the v4l2 mutex and registered bit.
		 */
		retval = led_classdev_register(&intf->dev, &shark->leds[i]);
		if (retval)
			v4l2_err(&shark->v4l2_dev,
				 "couldn't register led: %s\n",
				 shark->led_names[i]);
	}

	return 0;

err_init_tea:
	v4l2_device_unregister(&shark->v4l2_dev);
err_reg_dev:
	kfree(shark->transfer_buffer);
err_alloc_buffer:
	kfree(shark);

	return retval;
}

/* Specify the bcdDevice value, as the radioSHARK and radioSHARK2 share ids */
static struct usb_device_id usb_shark_device_table[] = {
	{ .match_flags = USB_DEVICE_ID_MATCH_DEVICE_AND_VERSION |
			 USB_DEVICE_ID_MATCH_INT_CLASS,
	  .idVendor     = 0x077d,
	  .idProduct    = 0x627a,
	  .bcdDevice_lo = 0x0001,
	  .bcdDevice_hi = 0x0001,
	  .bInterfaceClass = 3,
	},
	{ }
};
MODULE_DEVICE_TABLE(usb, usb_shark_device_table);

static struct usb_driver usb_shark_driver = {
	.name			= DRV_NAME,
	.probe			= usb_shark_probe,
	.disconnect		= usb_shark_disconnect,
	.id_table		= usb_shark_device_table,
};
module_usb_driver(usb_shark_driver);