// SPDX-License-Identifier: GPL-2.0+
//
// em28xx-core.c - driver for Empia EM2800/EM2820/2840 USB video capture devices
//
// Copyright (C) 2005 Ludovico Cavedon <cavedon@sssup.it>
//		      Markus Rechberger <mrechberger@gmail.com>
//		      Mauro Carvalho Chehab <mchehab@kernel.org>
//		      Sascha Sommer <saschasommer@freenet.de>
// Copyright (C) 2012 Frank Schäfer <fschaefer.oss@googlemail.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.

#include "em28xx.h"

#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/vmalloc.h>
#include <sound/ac97_codec.h>
#include <media/v4l2-common.h>

#define DRIVER_AUTHOR "Ludovico Cavedon <cavedon@sssup.it>, " \
		      "Markus Rechberger <mrechberger@gmail.com>, " \
		      "Mauro Carvalho Chehab <mchehab@kernel.org>, " \
		      "Sascha Sommer <saschasommer@freenet.de>"

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL v2");
MODULE_VERSION(EM28XX_VERSION);

/* #define ENABLE_DEBUG_ISOC_FRAMES */

static unsigned int core_debug;
module_param(core_debug, int, 0644);
MODULE_PARM_DESC(core_debug, "enable debug messages [core and isoc]");

#define em28xx_coredbg(fmt, arg...) do {				\
	if (core_debug)							\
		dev_printk(KERN_DEBUG, &dev->intf->dev,			\
			   "core: %s: " fmt, __func__, ## arg);		\
} while (0)

static unsigned int reg_debug;
module_param(reg_debug, int, 0644);
MODULE_PARM_DESC(reg_debug, "enable debug messages [URB reg]");

#define em28xx_regdbg(fmt, arg...) do {				\
	if (reg_debug)							\
		dev_printk(KERN_DEBUG, &dev->intf->dev,			\
			   "reg: %s: " fmt, __func__, ## arg);		\
} while (0)

/* FIXME: don't abuse core_debug */
#define em28xx_isocdbg(fmt, arg...) do {				\
	if (core_debug)							\
		dev_printk(KERN_DEBUG, &dev->intf->dev,			\
			   "core: %s: " fmt, __func__, ## arg);		\
} while (0)

/*
 * em28xx_read_reg_req()
 * reads data from the usb device specifying bRequest
 */
int em28xx_read_reg_req_len(struct em28xx *dev, u8 req, u16 reg,
			    char *buf, int len)
{
	int ret;
	struct usb_device *udev = interface_to_usbdev(dev->intf);
	int pipe = usb_rcvctrlpipe(udev, 0);

	if (dev->disconnected)
		return -ENODEV;

	if (len > URB_MAX_CTRL_SIZE)
		return -EINVAL;

	mutex_lock(&dev->ctrl_urb_lock);
	ret = usb_control_msg(udev, pipe, req,
			      USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			      0x0000, reg, dev->urb_buf, len, HZ);
	if (ret < 0) {
		em28xx_regdbg("(pipe 0x%08x): IN:  %02x %02x %02x %02x %02x %02x %02x %02x  failed with error %i\n",
			      pipe,
			      USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			      req, 0, 0,
			      reg & 0xff, reg >> 8,
			      len & 0xff, len >> 8, ret);
		mutex_unlock(&dev->ctrl_urb_lock);
		return usb_translate_errors(ret);
	}

	if (len)
		memcpy(buf, dev->urb_buf, len);

	mutex_unlock(&dev->ctrl_urb_lock);

	em28xx_regdbg("(pipe 0x%08x): IN:  %02x %02x %02x %02x %02x %02x %02x %02x <<< %*ph\n",
		      pipe, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
		      req, 0, 0,
		      reg & 0xff, reg >> 8,
		      len & 0xff, len >> 8, len, buf);

	return ret;
}

/*
 * em28xx_read_reg_req()
 * reads data from the usb device specifying bRequest
 */
int em28xx_read_reg_req(struct em28xx *dev, u8 req, u16 reg)
{
	int ret;
	u8 val;

	ret = em28xx_read_reg_req_len(dev, req, reg, &val, 1);
	if (ret < 0)
		return ret;

	return val;
}

int em28xx_read_reg(struct em28xx *dev, u16 reg)
{
	return em28xx_read_reg_req(dev, USB_REQ_GET_STATUS, reg);
}
EXPORT_SYMBOL_GPL(em28xx_read_reg);

/*
 * em28xx_write_regs_req()
 * sends data to the usb device, specifying bRequest
 */
int em28xx_write_regs_req(struct em28xx *dev, u8 req, u16 reg, char *buf,
			  int len)
{
	int ret;
	struct usb_device *udev = interface_to_usbdev(dev->intf);
	int pipe = usb_sndctrlpipe(udev, 0);

	if (dev->disconnected)
		return -ENODEV;

	if (len < 1 || len > URB_MAX_CTRL_SIZE)
		return -EINVAL;

	mutex_lock(&dev->ctrl_urb_lock);
	memcpy(dev->urb_buf, buf, len);
	ret = usb_control_msg(udev, pipe, req,
			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			      0x0000, reg, dev->urb_buf, len, HZ);
	mutex_unlock(&dev->ctrl_urb_lock);

	if (ret < 0) {
		em28xx_regdbg("(pipe 0x%08x): OUT:  %02x %02x %02x %02x %02x %02x %02x %02x >>> %*ph  failed with error %i\n",
			      pipe,
			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			      req, 0, 0,
			      reg & 0xff, reg >> 8,
			      len & 0xff, len >> 8, len, buf, ret);
		return usb_translate_errors(ret);
	}

	em28xx_regdbg("(pipe 0x%08x): OUT:  %02x %02x %02x %02x %02x %02x %02x %02x >>> %*ph\n",
		      pipe,
		      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
		      req, 0, 0,
		      reg & 0xff, reg >> 8,
		      len & 0xff, len >> 8, len, buf);

	if (dev->wait_after_write)
		msleep(dev->wait_after_write);

	return ret;
}

int em28xx_write_regs(struct em28xx *dev, u16 reg, char *buf, int len)
{
	return em28xx_write_regs_req(dev, USB_REQ_GET_STATUS, reg, buf, len);
}
EXPORT_SYMBOL_GPL(em28xx_write_regs);

/* Write a single register */
int em28xx_write_reg(struct em28xx *dev, u16 reg, u8 val)
{
	return em28xx_write_regs(dev, reg, &val, 1);
}
EXPORT_SYMBOL_GPL(em28xx_write_reg);

/*
 * em28xx_write_reg_bits()
 * sets only some bits (specified by bitmask) of a register, by first reading
 * the actual value
 */
int em28xx_write_reg_bits(struct em28xx *dev, u16 reg, u8 val,
			  u8 bitmask)
{
	int oldval;
	u8 newval;

	oldval = em28xx_read_reg(dev, reg);
	if (oldval < 0)
		return oldval;

	newval = (((u8)oldval) & ~bitmask) | (val & bitmask);

	return em28xx_write_regs(dev, reg, &newval, 1);
}
EXPORT_SYMBOL_GPL(em28xx_write_reg_bits);

/*
 * em28xx_toggle_reg_bits()
 * toggles/inverts the bits (specified by bitmask) of a register
 */
int em28xx_toggle_reg_bits(struct em28xx *dev, u16 reg, u8 bitmask)
{
	int oldval;
	u8 newval;

	oldval = em28xx_read_reg(dev, reg);
	if (oldval < 0)
		return oldval;

	newval = (~oldval & bitmask) | (oldval & ~bitmask);

	return em28xx_write_reg(dev, reg, newval);
}
EXPORT_SYMBOL_GPL(em28xx_toggle_reg_bits);

/*
 * em28xx_is_ac97_ready()
 * Checks if ac97 is ready
 */
static int em28xx_is_ac97_ready(struct em28xx *dev)
{
	unsigned long timeout = jiffies + msecs_to_jiffies(EM28XX_AC97_XFER_TIMEOUT);
	int ret;

	/* Wait up to 50 ms for AC97 command to complete */
	while (time_is_after_jiffies(timeout)) {
		ret = em28xx_read_reg(dev, EM28XX_R43_AC97BUSY);
		if (ret < 0)
			return ret;

		if (!(ret & 0x01))
			return 0;
		msleep(5);
	}

	dev_warn(&dev->intf->dev,
		 "AC97 command still being executed: not handled properly!\n");
	return -EBUSY;
}

/*
 * em28xx_read_ac97()
 * write a 16 bit value to the specified AC97 address (LSB first!)
 */
int em28xx_read_ac97(struct em28xx *dev, u8 reg)
{
	int ret;
	u8 addr = (reg & 0x7f) | 0x80;
	__le16 val;

	ret = em28xx_is_ac97_ready(dev);
	if (ret < 0)
		return ret;

	ret = em28xx_write_regs(dev, EM28XX_R42_AC97ADDR, &addr, 1);
	if (ret < 0)
		return ret;

	ret = dev->em28xx_read_reg_req_len(dev, 0, EM28XX_R40_AC97LSB,
					   (u8 *)&val, sizeof(val));

	if (ret < 0)
		return ret;
	return le16_to_cpu(val);
}
EXPORT_SYMBOL_GPL(em28xx_read_ac97);

/*
 * em28xx_write_ac97()
 * write a 16 bit value to the specified AC97 address (LSB first!)
 */
int em28xx_write_ac97(struct em28xx *dev, u8 reg, u16 val)
{
	int ret;
	u8 addr = reg & 0x7f;
	__le16 value;

	value = cpu_to_le16(val);

	ret = em28xx_is_ac97_ready(dev);
	if (ret < 0)
		return ret;

	ret = em28xx_write_regs(dev, EM28XX_R40_AC97LSB, (u8 *)&value, 2);
	if (ret < 0)
		return ret;

	ret = em28xx_write_regs(dev, EM28XX_R42_AC97ADDR, &addr, 1);
	if (ret < 0)
		return ret;

	return 0;
}
EXPORT_SYMBOL_GPL(em28xx_write_ac97);

struct em28xx_vol_itable {
	enum em28xx_amux mux;
	u8		 reg;
};

static struct em28xx_vol_itable inputs[] = {
	{ EM28XX_AMUX_VIDEO,	AC97_VIDEO	},
	{ EM28XX_AMUX_LINE_IN,	AC97_LINE	},
	{ EM28XX_AMUX_PHONE,	AC97_PHONE	},
	{ EM28XX_AMUX_MIC,	AC97_MIC	},
	{ EM28XX_AMUX_CD,	AC97_CD		},
	{ EM28XX_AMUX_AUX,	AC97_AUX	},
	{ EM28XX_AMUX_PCM_OUT,	AC97_PCM	},
};

static int set_ac97_input(struct em28xx *dev)
{
	int ret, i;
	enum em28xx_amux amux = dev->ctl_ainput;

	/*
	 * EM28XX_AMUX_VIDEO2 is a special case used to indicate that
	 * em28xx should point to LINE IN, while AC97 should use VIDEO
	 */
	if (amux == EM28XX_AMUX_VIDEO2)
		amux = EM28XX_AMUX_VIDEO;

	/* Mute all entres but the one that were selected */
	for (i = 0; i < ARRAY_SIZE(inputs); i++) {
		if (amux == inputs[i].mux)
			ret = em28xx_write_ac97(dev, inputs[i].reg, 0x0808);
		else
			ret = em28xx_write_ac97(dev, inputs[i].reg, 0x8000);

		if (ret < 0)
			dev_warn(&dev->intf->dev,
				 "couldn't setup AC97 register %d\n",
				 inputs[i].reg);
	}
	return 0;
}

static int em28xx_set_audio_source(struct em28xx *dev)
{
	int ret;
	u8 input;

	if (dev->board.is_em2800) {
		if (dev->ctl_ainput == EM28XX_AMUX_VIDEO)
			input = EM2800_AUDIO_SRC_TUNER;
		else
			input = EM2800_AUDIO_SRC_LINE;

		ret = em28xx_write_regs(dev, EM2800_R08_AUDIOSRC, &input, 1);
		if (ret < 0)
			return ret;
	}

	if (dev->has_msp34xx) {
		input = EM28XX_AUDIO_SRC_TUNER;
	} else {
		switch (dev->ctl_ainput) {
		case EM28XX_AMUX_VIDEO:
			input = EM28XX_AUDIO_SRC_TUNER;
			break;
		default:
			input = EM28XX_AUDIO_SRC_LINE;
			break;
		}
	}

	if (dev->board.mute_gpio && dev->mute)
		em28xx_gpio_set(dev, dev->board.mute_gpio);
	else
		em28xx_gpio_set(dev, INPUT(dev->ctl_input)->gpio);

	ret = em28xx_write_reg_bits(dev, EM28XX_R0E_AUDIOSRC, input, 0xc0);
	if (ret < 0)
		return ret;
	usleep_range(10000, 11000);

	switch (dev->audio_mode.ac97) {
	case EM28XX_NO_AC97:
		break;
	default:
		ret = set_ac97_input(dev);
	}

	return ret;
}

struct em28xx_vol_otable {
	enum em28xx_aout mux;
	u8		 reg;
};

static const struct em28xx_vol_otable outputs[] = {
	{ EM28XX_AOUT_MASTER, AC97_MASTER		},
	{ EM28XX_AOUT_LINE,   AC97_HEADPHONE		},
	{ EM28XX_AOUT_MONO,   AC97_MASTER_MONO		},
	{ EM28XX_AOUT_LFE,    AC97_CENTER_LFE_MASTER	},
	{ EM28XX_AOUT_SURR,   AC97_SURROUND_MASTER	},
};

int em28xx_audio_analog_set(struct em28xx *dev)
{
	int ret, i;
	u8 xclk;

	if (dev->int_audio_type == EM28XX_INT_AUDIO_NONE)
		return 0;

	/*
	 * It is assumed that all devices use master volume for output.
	 * It would be possible to use also line output.
	 */
	if (dev->audio_mode.ac97 != EM28XX_NO_AC97) {
		/* Mute all outputs */
		for (i = 0; i < ARRAY_SIZE(outputs); i++) {
			ret = em28xx_write_ac97(dev, outputs[i].reg, 0x8000);
			if (ret < 0)
				dev_warn(&dev->intf->dev,
					 "couldn't setup AC97 register %d\n",
					 outputs[i].reg);
		}
	}

	xclk = dev->board.xclk & 0x7f;
	if (!dev->mute)
		xclk |= EM28XX_XCLK_AUDIO_UNMUTE;

	ret = em28xx_write_reg(dev, EM28XX_R0F_XCLK, xclk);
	if (ret < 0)
		return ret;
	usleep_range(10000, 11000);

	/* Selects the proper audio input */
	ret = em28xx_set_audio_source(dev);

	/* Sets volume */
	if (dev->audio_mode.ac97 != EM28XX_NO_AC97) {
		int vol;

		em28xx_write_ac97(dev, AC97_POWERDOWN, 0x4200);
		em28xx_write_ac97(dev, AC97_EXTENDED_STATUS, 0x0031);
		em28xx_write_ac97(dev, AC97_PCM_LR_ADC_RATE, 0xbb80);

		/* LSB: left channel - both channels with the same level */
		vol = (0x1f - dev->volume) | ((0x1f - dev->volume) << 8);

		/* Mute device, if needed */
		if (dev->mute)
			vol |= 0x8000;

		/* Sets volume */
		for (i = 0; i < ARRAY_SIZE(outputs); i++) {
			if (dev->ctl_aoutput & outputs[i].mux)
				ret = em28xx_write_ac97(dev, outputs[i].reg,
							vol);
			if (ret < 0)
				dev_warn(&dev->intf->dev,
					 "couldn't setup AC97 register %d\n",
					 outputs[i].reg);
		}

		if (dev->ctl_aoutput & EM28XX_AOUT_PCM_IN) {
			int sel = ac97_return_record_select(dev->ctl_aoutput);

			/*
			 * Use the same input for both left and right
			 * channels
			 */
			sel |= (sel << 8);

			em28xx_write_ac97(dev, AC97_REC_SEL, sel);
		}
	}

	return ret;
}
EXPORT_SYMBOL_GPL(em28xx_audio_analog_set);

int em28xx_audio_setup(struct em28xx *dev)
{
	int vid1, vid2, feat, cfg;
	u32 vid = 0;
	u8 i2s_samplerates;

	if (dev->chip_id == CHIP_ID_EM2870 ||
	    dev->chip_id == CHIP_ID_EM2874 ||
	    dev->chip_id == CHIP_ID_EM28174 ||
	    dev->chip_id == CHIP_ID_EM28178) {
		/* Digital only device - don't load any alsa module */
		dev->int_audio_type = EM28XX_INT_AUDIO_NONE;
		dev->usb_audio_type = EM28XX_USB_AUDIO_NONE;
		return 0;
	}

	/* See how this device is configured */
	cfg = em28xx_read_reg(dev, EM28XX_R00_CHIPCFG);
	dev_info(&dev->intf->dev, "Config register raw data: 0x%02x\n", cfg);
	if (cfg < 0) { /* Register read error */
		/* Be conservative */
		dev->int_audio_type = EM28XX_INT_AUDIO_AC97;
	} else if ((cfg & EM28XX_CHIPCFG_AUDIOMASK) == 0x00) {
		/* The device doesn't have vendor audio at all */
		dev->int_audio_type = EM28XX_INT_AUDIO_NONE;
		dev->usb_audio_type = EM28XX_USB_AUDIO_NONE;
		return 0;
	} else if ((cfg & EM28XX_CHIPCFG_AUDIOMASK) != EM28XX_CHIPCFG_AC97) {
		dev->int_audio_type = EM28XX_INT_AUDIO_I2S;
		if (dev->chip_id < CHIP_ID_EM2860 &&
		    (cfg & EM28XX_CHIPCFG_AUDIOMASK) ==
		    EM2820_CHIPCFG_I2S_1_SAMPRATE)
			i2s_samplerates = 1;
		else if (dev->chip_id >= CHIP_ID_EM2860 &&
			 (cfg & EM28XX_CHIPCFG_AUDIOMASK) ==
			 EM2860_CHIPCFG_I2S_5_SAMPRATES)
			i2s_samplerates = 5;
		else
			i2s_samplerates = 3;
		dev_info(&dev->intf->dev, "I2S Audio (%d sample rate(s))\n",
			 i2s_samplerates);
		/* Skip the code that does AC97 vendor detection */
		dev->audio_mode.ac97 = EM28XX_NO_AC97;
		goto init_audio;
	} else {
		dev->int_audio_type = EM28XX_INT_AUDIO_AC97;
	}

	dev->audio_mode.ac97 = EM28XX_AC97_OTHER;

	vid1 = em28xx_read_ac97(dev, AC97_VENDOR_ID1);
	if (vid1 < 0) {
		/*
		 * Device likely doesn't support AC97
		 * Note: (some) em2800 devices without eeprom reports 0x91 on
		 *	 CHIPCFG register, even not having an AC97 chip
		 */
		dev_warn(&dev->intf->dev,
			 "AC97 chip type couldn't be determined\n");
		dev->audio_mode.ac97 = EM28XX_NO_AC97;
		if (dev->usb_audio_type == EM28XX_USB_AUDIO_VENDOR)
			dev->usb_audio_type = EM28XX_USB_AUDIO_NONE;
		dev->int_audio_type = EM28XX_INT_AUDIO_NONE;
		goto init_audio;
	}

	vid2 = em28xx_read_ac97(dev, AC97_VENDOR_ID2);
	if (vid2 < 0)
		goto init_audio;

	vid = vid1 << 16 | vid2;
	dev_warn(&dev->intf->dev, "AC97 vendor ID = 0x%08x\n", vid);

	feat = em28xx_read_ac97(dev, AC97_RESET);
	if (feat < 0)
		goto init_audio;

	dev_warn(&dev->intf->dev, "AC97 features = 0x%04x\n", feat);

	/* Try to identify what audio processor we have */
	if ((vid == 0xffffffff || vid == 0x83847650) && feat == 0x6a90)
		dev->audio_mode.ac97 = EM28XX_AC97_EM202;
	else if ((vid >> 8) == 0x838476)
		dev->audio_mode.ac97 = EM28XX_AC97_SIGMATEL;

init_audio:
	/* Reports detected AC97 processor */
	switch (dev->audio_mode.ac97) {
	case EM28XX_NO_AC97:
		dev_info(&dev->intf->dev, "No AC97 audio processor\n");
		break;
	case EM28XX_AC97_EM202:
		dev_info(&dev->intf->dev,
			 "Empia 202 AC97 audio processor detected\n");
		break;
	case EM28XX_AC97_SIGMATEL:
		dev_info(&dev->intf->dev,
			 "Sigmatel audio processor detected (stac 97%02x)\n",
			 vid & 0xff);
		break;
	case EM28XX_AC97_OTHER:
		dev_warn(&dev->intf->dev,
			 "Unknown AC97 audio processor detected!\n");
		break;
	default:
		break;
	}

	return em28xx_audio_analog_set(dev);
}
EXPORT_SYMBOL_GPL(em28xx_audio_setup);

const struct em28xx_led *em28xx_find_led(struct em28xx *dev,
					 enum em28xx_led_role role)
{
	if (dev->board.leds) {
		u8 k = 0;

		while (dev->board.leds[k].role >= 0 &&
		       dev->board.leds[k].role < EM28XX_NUM_LED_ROLES) {
			if (dev->board.leds[k].role == role)
				return &dev->board.leds[k];
			k++;
		}
	}
	return NULL;
}
EXPORT_SYMBOL_GPL(em28xx_find_led);

int em28xx_capture_start(struct em28xx *dev, int start)
{
	int rc;
	const struct em28xx_led *led = NULL;

	if (dev->chip_id == CHIP_ID_EM2874 ||
	    dev->chip_id == CHIP_ID_EM2884 ||
	    dev->chip_id == CHIP_ID_EM28174 ||
	    dev->chip_id == CHIP_ID_EM28178) {
		/* The Transport Stream Enable Register moved in em2874 */
		if (dev->dvb_xfer_bulk) {
			/* Max Tx Size = 188 * 256 = 48128 - LCM(188,512) * 2 */
			em28xx_write_reg(dev, (dev->ts == PRIMARY_TS) ?
					 EM2874_R5D_TS1_PKT_SIZE :
					 EM2874_R5E_TS2_PKT_SIZE,
					 0xff);
		} else {
			/* ISOC Maximum Transfer Size = 188 * 5 */
			em28xx_write_reg(dev, (dev->ts == PRIMARY_TS) ?
					 EM2874_R5D_TS1_PKT_SIZE :
					 EM2874_R5E_TS2_PKT_SIZE,
					 dev->dvb_max_pkt_size_isoc / 188);
		}
		if (dev->ts == PRIMARY_TS)
			rc = em28xx_write_reg_bits(dev,
						   EM2874_R5F_TS_ENABLE,
						   start ? EM2874_TS1_CAPTURE_ENABLE : 0x00,
						   EM2874_TS1_CAPTURE_ENABLE | EM2874_TS1_FILTER_ENABLE | EM2874_TS1_NULL_DISCARD);
		else
			rc = em28xx_write_reg_bits(dev,
						   EM2874_R5F_TS_ENABLE,
						   start ? EM2874_TS2_CAPTURE_ENABLE : 0x00,
						   EM2874_TS2_CAPTURE_ENABLE | EM2874_TS2_FILTER_ENABLE | EM2874_TS2_NULL_DISCARD);
	} else {
		/* FIXME: which is the best order? */
		/* video registers are sampled by VREF */
		rc = em28xx_write_reg_bits(dev, EM28XX_R0C_USBSUSP,
					   start ? 0x10 : 0x00, 0x10);
		if (rc < 0)
			return rc;

		if (start) {
			if (dev->is_webcam)
				rc = em28xx_write_reg(dev, 0x13, 0x0c);

			/* Enable video capture */
			rc = em28xx_write_reg(dev, 0x48, 0x00);
			if (rc < 0)
				return rc;

			if (dev->mode == EM28XX_ANALOG_MODE)
				rc = em28xx_write_reg(dev,
						      EM28XX_R12_VINENABLE,
						      0x67);
			else
				rc = em28xx_write_reg(dev,
						      EM28XX_R12_VINENABLE,
						      0x37);
			if (rc < 0)
				return rc;

			usleep_range(10000, 11000);
		} else {
			/* disable video capture */
			rc = em28xx_write_reg(dev, EM28XX_R12_VINENABLE, 0x27);
		}
	}

	if (dev->mode == EM28XX_ANALOG_MODE)
		led = em28xx_find_led(dev, EM28XX_LED_ANALOG_CAPTURING);
	else
		led = em28xx_find_led(dev, EM28XX_LED_DIGITAL_CAPTURING);

	if (led)
		em28xx_write_reg_bits(dev, led->gpio_reg,
				      (!start ^ led->inverted) ?
				      ~led->gpio_mask : led->gpio_mask,
				      led->gpio_mask);

	return rc;
}

int em28xx_gpio_set(struct em28xx *dev, const struct em28xx_reg_seq *gpio)
{
	int rc = 0;

	if (!gpio)
		return rc;

	if (dev->mode != EM28XX_SUSPEND) {
		em28xx_write_reg(dev, 0x48, 0x00);
		if (dev->mode == EM28XX_ANALOG_MODE)
			em28xx_write_reg(dev, EM28XX_R12_VINENABLE, 0x67);
		else
			em28xx_write_reg(dev, EM28XX_R12_VINENABLE, 0x37);
		usleep_range(10000, 11000);
	}

	/* Send GPIO reset sequences specified at board entry */
	while (gpio->sleep >= 0) {
		if (gpio->reg >= 0) {
			rc = em28xx_write_reg_bits(dev,
						   gpio->reg,
						   gpio->val,
						   gpio->mask);
			if (rc < 0)
				return rc;
		}
		if (gpio->sleep > 0)
			msleep(gpio->sleep);

		gpio++;
	}
	return rc;
}
EXPORT_SYMBOL_GPL(em28xx_gpio_set);

int em28xx_set_mode(struct em28xx *dev, enum em28xx_mode set_mode)
{
	if (dev->mode == set_mode)
		return 0;

	if (set_mode == EM28XX_SUSPEND) {
		dev->mode = set_mode;

		/* FIXME: add suspend support for ac97 */

		return em28xx_gpio_set(dev, dev->board.suspend_gpio);
	}

	dev->mode = set_mode;

	if (dev->mode == EM28XX_DIGITAL_MODE)
		return em28xx_gpio_set(dev, dev->board.dvb_gpio);
	else
		return em28xx_gpio_set(dev, INPUT(dev->ctl_input)->gpio);
}
EXPORT_SYMBOL_GPL(em28xx_set_mode);

/*
 *URB control
 */

/*
 * URB completion handler for isoc/bulk transfers
 */
static void em28xx_irq_callback(struct urb *urb)
{
	struct em28xx *dev = urb->context;
	unsigned long flags;
	int i;

	switch (urb->status) {
	case 0:             /* success */
	case -ETIMEDOUT:    /* NAK */
		break;
	case -ECONNRESET:   /* kill */
	case -ENOENT:
	case -ESHUTDOWN:
		return;
	default:            /* error */
		em28xx_isocdbg("urb completion error %d.\n", urb->status);
		break;
	}

	/* Copy data from URB */
	spin_lock_irqsave(&dev->slock, flags);
	dev->usb_ctl.urb_data_copy(dev, urb);
	spin_unlock_irqrestore(&dev->slock, flags);

	/* Reset urb buffers */
	for (i = 0; i < urb->number_of_packets; i++) {
		/* isoc only (bulk: number_of_packets = 0) */
		urb->iso_frame_desc[i].status = 0;
		urb->iso_frame_desc[i].actual_length = 0;
	}
	urb->status = 0;

	urb->status = usb_submit_urb(urb, GFP_ATOMIC);
	if (urb->status) {
		em28xx_isocdbg("urb resubmit failed (error=%i)\n",
			       urb->status);
	}
}

/*
 * Stop and Deallocate URBs
 */
void em28xx_uninit_usb_xfer(struct em28xx *dev, enum em28xx_mode mode)
{
	struct urb *urb;
	struct em28xx_usb_bufs *usb_bufs;
	int i;

	em28xx_isocdbg("called %s in mode %d\n", __func__, mode);

	if (mode == EM28XX_DIGITAL_MODE)
		usb_bufs = &dev->usb_ctl.digital_bufs;
	else
		usb_bufs = &dev->usb_ctl.analog_bufs;

	for (i = 0; i < usb_bufs->num_bufs; i++) {
		urb = usb_bufs->urb[i];
		if (urb) {
			if (!irqs_disabled())
				usb_kill_urb(urb);
			else
				usb_unlink_urb(urb);

			usb_free_urb(urb);
			usb_bufs->urb[i] = NULL;
		}
	}

	kfree(usb_bufs->urb);
	kfree(usb_bufs->buf);

	usb_bufs->urb = NULL;
	usb_bufs->buf = NULL;
	usb_bufs->num_bufs = 0;

	em28xx_capture_start(dev, 0);
}
EXPORT_SYMBOL_GPL(em28xx_uninit_usb_xfer);

/*
 * Stop URBs
 */
void em28xx_stop_urbs(struct em28xx *dev)
{
	int i;
	struct urb *urb;
	struct em28xx_usb_bufs *isoc_bufs = &dev->usb_ctl.digital_bufs;

	em28xx_isocdbg("called %s\n", __func__);

	for (i = 0; i < isoc_bufs->num_bufs; i++) {
		urb = isoc_bufs->urb[i];
		if (urb) {
			if (!irqs_disabled())
				usb_kill_urb(urb);
			else
				usb_unlink_urb(urb);
		}
	}

	em28xx_capture_start(dev, 0);
}
EXPORT_SYMBOL_GPL(em28xx_stop_urbs);

/*
 * Allocate URBs
 */
int em28xx_alloc_urbs(struct em28xx *dev, enum em28xx_mode mode, int xfer_bulk,
		      int num_bufs, int max_pkt_size, int packet_multiplier)
{
	struct em28xx_usb_bufs *usb_bufs;
	struct urb *urb;
	struct usb_device *udev = interface_to_usbdev(dev->intf);
	int i;
	int sb_size, pipe;
	int j, k;

	em28xx_isocdbg("em28xx: called %s in mode %d\n", __func__, mode);

	/*
	 * Check mode and if we have an endpoint for the selected
	 * transfer type, select buffer
	 */
	if (mode == EM28XX_DIGITAL_MODE) {
		if ((xfer_bulk && !dev->dvb_ep_bulk) ||
		    (!xfer_bulk && !dev->dvb_ep_isoc)) {
			dev_err(&dev->intf->dev,
				"no endpoint for DVB mode and transfer type %d\n",
				xfer_bulk > 0);
			return -EINVAL;
		}
		usb_bufs = &dev->usb_ctl.digital_bufs;
	} else if (mode == EM28XX_ANALOG_MODE) {
		if ((xfer_bulk && !dev->analog_ep_bulk) ||
		    (!xfer_bulk && !dev->analog_ep_isoc)) {
			dev_err(&dev->intf->dev,
				"no endpoint for analog mode and transfer type %d\n",
				xfer_bulk > 0);
			return -EINVAL;
		}
		usb_bufs = &dev->usb_ctl.analog_bufs;
	} else {
		dev_err(&dev->intf->dev, "invalid mode selected\n");
		return -EINVAL;
	}

	/* De-allocates all pending stuff */
	em28xx_uninit_usb_xfer(dev, mode);

	usb_bufs->num_bufs = num_bufs;

	usb_bufs->urb = kcalloc(num_bufs, sizeof(void *), GFP_KERNEL);
	if (!usb_bufs->urb)
		return -ENOMEM;

	usb_bufs->buf = kcalloc(num_bufs, sizeof(void *), GFP_KERNEL);
	if (!usb_bufs->buf) {
		kfree(usb_bufs->urb);
		return -ENOMEM;
	}

	usb_bufs->max_pkt_size = max_pkt_size;
	if (xfer_bulk)
		usb_bufs->num_packets = 0;
	else
		usb_bufs->num_packets = packet_multiplier;
	dev->usb_ctl.vid_buf = NULL;
	dev->usb_ctl.vbi_buf = NULL;

	sb_size = packet_multiplier * usb_bufs->max_pkt_size;

	/* allocate urbs and transfer buffers */
	for (i = 0; i < usb_bufs->num_bufs; i++) {
		urb = usb_alloc_urb(usb_bufs->num_packets, GFP_KERNEL);
		if (!urb) {
			em28xx_uninit_usb_xfer(dev, mode);
			return -ENOMEM;
		}
		usb_bufs->urb[i] = urb;

		usb_bufs->buf[i] = kzalloc(sb_size, GFP_KERNEL);
		if (!usb_bufs->buf[i]) {
			for (i--; i >= 0; i--)
				kfree(usb_bufs->buf[i]);

			em28xx_uninit_usb_xfer(dev, mode);
			return -ENOMEM;
		}

		urb->transfer_flags = URB_FREE_BUFFER;

		if (xfer_bulk) { /* bulk */
			pipe = usb_rcvbulkpipe(udev,
					       mode == EM28XX_ANALOG_MODE ?
					       dev->analog_ep_bulk :
					       dev->dvb_ep_bulk);
			usb_fill_bulk_urb(urb, udev, pipe, usb_bufs->buf[i],
					  sb_size, em28xx_irq_callback, dev);
		} else { /* isoc */
			pipe = usb_rcvisocpipe(udev,
					       mode == EM28XX_ANALOG_MODE ?
					       dev->analog_ep_isoc :
					       dev->dvb_ep_isoc);
			usb_fill_int_urb(urb, udev, pipe, usb_bufs->buf[i],
					 sb_size, em28xx_irq_callback, dev, 1);
			urb->transfer_flags |= URB_ISO_ASAP;
			k = 0;
			for (j = 0; j < usb_bufs->num_packets; j++) {
				urb->iso_frame_desc[j].offset = k;
				urb->iso_frame_desc[j].length =
							usb_bufs->max_pkt_size;
				k += usb_bufs->max_pkt_size;
			}
		}

		urb->number_of_packets = usb_bufs->num_packets;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(em28xx_alloc_urbs);

/*
 * Allocate URBs and start IRQ
 */
int em28xx_init_usb_xfer(struct em28xx *dev, enum em28xx_mode mode,
			 int xfer_bulk, int num_bufs, int max_pkt_size,
		    int packet_multiplier,
		    int (*urb_data_copy)(struct em28xx *dev, struct urb *urb))
{
	struct em28xx_dmaqueue *dma_q = &dev->vidq;
	struct em28xx_dmaqueue *vbi_dma_q = &dev->vbiq;
	struct em28xx_usb_bufs *usb_bufs;
	struct usb_device *udev = interface_to_usbdev(dev->intf);
	int i;
	int rc;
	int alloc;

	em28xx_isocdbg("em28xx: called %s in mode %d\n", __func__, mode);

	dev->usb_ctl.urb_data_copy = urb_data_copy;

	if (mode == EM28XX_DIGITAL_MODE) {
		usb_bufs = &dev->usb_ctl.digital_bufs;
		/* no need to free/alloc usb buffers in digital mode */
		alloc = 0;
	} else {
		usb_bufs = &dev->usb_ctl.analog_bufs;
		alloc = 1;
	}

	if (alloc) {
		rc = em28xx_alloc_urbs(dev, mode, xfer_bulk, num_bufs,
				       max_pkt_size, packet_multiplier);
		if (rc)
			return rc;
	}

	if (xfer_bulk) {
		rc = usb_clear_halt(udev, usb_bufs->urb[0]->pipe);
		if (rc < 0) {
			dev_err(&dev->intf->dev,
				"failed to clear USB bulk endpoint stall/halt condition (error=%i)\n",
			       rc);
			em28xx_uninit_usb_xfer(dev, mode);
			return rc;
		}
	}

	init_waitqueue_head(&dma_q->wq);
	init_waitqueue_head(&vbi_dma_q->wq);

	em28xx_capture_start(dev, 1);

	/* submit urbs and enables IRQ */
	for (i = 0; i < usb_bufs->num_bufs; i++) {
		rc = usb_submit_urb(usb_bufs->urb[i], GFP_KERNEL);
		if (rc) {
			dev_err(&dev->intf->dev,
				"submit of urb %i failed (error=%i)\n", i, rc);
			em28xx_uninit_usb_xfer(dev, mode);
			return rc;
		}
	}

	return 0;
}
EXPORT_SYMBOL_GPL(em28xx_init_usb_xfer);

/*
 * Device control list
 */

static LIST_HEAD(em28xx_devlist);
static DEFINE_MUTEX(em28xx_devlist_mutex);

/*
 * Extension interface
 */

static LIST_HEAD(em28xx_extension_devlist);

int em28xx_register_extension(struct em28xx_ops *ops)
{
	struct em28xx *dev = NULL;

	mutex_lock(&em28xx_devlist_mutex);
	list_add_tail(&ops->next, &em28xx_extension_devlist);
	list_for_each_entry(dev, &em28xx_devlist, devlist) {
		if (ops->init) {
			ops->init(dev);
			if (dev->dev_next)
				ops->init(dev->dev_next);
		}
	}
	mutex_unlock(&em28xx_devlist_mutex);
	pr_info("em28xx: Registered (%s) extension\n", ops->name);
	return 0;
}
EXPORT_SYMBOL(em28xx_register_extension);

void em28xx_unregister_extension(struct em28xx_ops *ops)
{
	struct em28xx *dev = NULL;

	mutex_lock(&em28xx_devlist_mutex);
	list_for_each_entry(dev, &em28xx_devlist, devlist) {
		if (ops->fini) {
			if (dev->dev_next)
				ops->fini(dev->dev_next);
			ops->fini(dev);
		}
	}
	list_del(&ops->next);
	mutex_unlock(&em28xx_devlist_mutex);
	pr_info("em28xx: Removed (%s) extension\n", ops->name);
}
EXPORT_SYMBOL(em28xx_unregister_extension);

void em28xx_init_extension(struct em28xx *dev)
{
	const struct em28xx_ops *ops = NULL;

	mutex_lock(&em28xx_devlist_mutex);
	list_add_tail(&dev->devlist, &em28xx_devlist);
	list_for_each_entry(ops, &em28xx_extension_devlist, next) {
		if (ops->init) {
			ops->init(dev);
			if (dev->dev_next)
				ops->init(dev->dev_next);
		}
	}
	mutex_unlock(&em28xx_devlist_mutex);
}

void em28xx_close_extension(struct em28xx *dev)
{
	const struct em28xx_ops *ops = NULL;

	mutex_lock(&em28xx_devlist_mutex);
	list_for_each_entry(ops, &em28xx_extension_devlist, next) {
		if (ops->fini) {
			if (dev->dev_next)
				ops->fini(dev->dev_next);
			ops->fini(dev);
		}
	}
	list_del(&dev->devlist);
	mutex_unlock(&em28xx_devlist_mutex);
}

int em28xx_suspend_extension(struct em28xx *dev)
{
	const struct em28xx_ops *ops = NULL;

	dev_info(&dev->intf->dev, "Suspending extensions\n");
	mutex_lock(&em28xx_devlist_mutex);
	list_for_each_entry(ops, &em28xx_extension_devlist, next) {
		if (ops->suspend)
			ops->suspend(dev);
		if (dev->dev_next)
			ops->suspend(dev->dev_next);
	}
	mutex_unlock(&em28xx_devlist_mutex);
	return 0;
}

int em28xx_resume_extension(struct em28xx *dev)
{
	const struct em28xx_ops *ops = NULL;

	dev_info(&dev->intf->dev, "Resuming extensions\n");
	mutex_lock(&em28xx_devlist_mutex);
	list_for_each_entry(ops, &em28xx_extension_devlist, next) {
		if (!ops->resume)
			continue;
		ops->resume(dev);
		if (dev->dev_next)
			ops->resume(dev->dev_next);
	}
	mutex_unlock(&em28xx_devlist_mutex);
	return 0;
}