Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 739 insertions, 0 deletions

diff --git a/drivers/media/pci/ivtv/ivtv-i2c.c b/drivers/media/pci/ivtv/ivtv-i2c.c
new file mode 100644
index 000000000..c052c57c6
--- /dev/null
+++ b/drivers/media/pci/ivtv/ivtv-i2c.c
@@ -0,0 +1,739 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+    I2C functions
+    Copyright (C) 2003-2004  Kevin Thayer <nufan_wfk at yahoo.com>
+    Copyright (C) 2005-2007  Hans Verkuil <hverkuil@xs4all.nl>
+
+ */
+
+/*
+    This file includes an i2c implementation that was reverse engineered
+    from the Hauppauge windows driver.  Older ivtv versions used i2c-algo-bit,
+    which whilst fine under most circumstances, had trouble with the Zilog
+    CPU on the PVR-150 which handles IR functions (occasional inability to
+    communicate with the chip until it was reset) and also with the i2c
+    bus being completely unreachable when multiple PVR cards were present.
+
+    The implementation is very similar to i2c-algo-bit, but there are enough
+    subtle differences that the two are hard to merge.  The general strategy
+    employed by i2c-algo-bit is to use udelay() to implement the timing
+    when putting out bits on the scl/sda lines.  The general strategy taken
+    here is to poll the lines for state changes (see ivtv_waitscl and
+    ivtv_waitsda).  In addition there are small delays at various locations
+    which poll the SCL line 5 times (ivtv_scldelay).  I would guess that
+    since this is memory mapped I/O that the length of those delays is tied
+    to the PCI bus clock.  There is some extra code to do with recovery
+    and retries.  Since it is not known what causes the actual i2c problems
+    in the first place, the only goal if one was to attempt to use
+    i2c-algo-bit would be to try to make it follow the same code path.
+    This would be a lot of work, and I'm also not convinced that it would
+    provide a generic benefit to i2c-algo-bit.  Therefore consider this
+    an engineering solution -- not pretty, but it works.
+
+    Some more general comments about what we are doing:
+
+    The i2c bus is a 2 wire serial bus, with clock (SCL) and data (SDA)
+    lines.  To communicate on the bus (as a master, we don't act as a slave),
+    we first initiate a start condition (ivtv_start).  We then write the
+    address of the device that we want to communicate with, along with a flag
+    that indicates whether this is a read or a write.  The slave then issues
+    an ACK signal (ivtv_ack), which tells us that it is ready for reading /
+    writing.  We then proceed with reading or writing (ivtv_read/ivtv_write),
+    and finally issue a stop condition (ivtv_stop) to make the bus available
+    to other masters.
+
+    There is an additional form of transaction where a write may be
+    immediately followed by a read.  In this case, there is no intervening
+    stop condition.  (Only the msp3400 chip uses this method of data transfer).
+ */
+
+#include "ivtv-driver.h"
+#include "ivtv-cards.h"
+#include "ivtv-gpio.h"
+#include "ivtv-i2c.h"
+#include <media/drv-intf/cx25840.h>
+
+/* i2c implementation for cx23415/6 chip, ivtv project.
+ * Author: Kevin Thayer (nufan_wfk at yahoo.com)
+ */
+/* i2c stuff */
+#define IVTV_REG_I2C_SETSCL_OFFSET 0x7000
+#define IVTV_REG_I2C_SETSDA_OFFSET 0x7004
+#define IVTV_REG_I2C_GETSCL_OFFSET 0x7008
+#define IVTV_REG_I2C_GETSDA_OFFSET 0x700c
+
+#define IVTV_CS53L32A_I2C_ADDR		0x11
+#define IVTV_M52790_I2C_ADDR		0x48
+#define IVTV_CX25840_I2C_ADDR		0x44
+#define IVTV_SAA7115_I2C_ADDR		0x21
+#define IVTV_SAA7127_I2C_ADDR		0x44
+#define IVTV_SAA717x_I2C_ADDR		0x21
+#define IVTV_MSP3400_I2C_ADDR		0x40
+#define IVTV_HAUPPAUGE_I2C_ADDR		0x50
+#define IVTV_WM8739_I2C_ADDR		0x1a
+#define IVTV_WM8775_I2C_ADDR		0x1b
+#define IVTV_TEA5767_I2C_ADDR		0x60
+#define IVTV_UPD64031A_I2C_ADDR		0x12
+#define IVTV_UPD64083_I2C_ADDR		0x5c
+#define IVTV_VP27SMPX_I2C_ADDR		0x5b
+#define IVTV_M52790_I2C_ADDR		0x48
+#define IVTV_AVERMEDIA_IR_RX_I2C_ADDR	0x40
+#define IVTV_HAUP_EXT_IR_RX_I2C_ADDR	0x1a
+#define IVTV_HAUP_INT_IR_RX_I2C_ADDR	0x18
+#define IVTV_Z8F0811_IR_TX_I2C_ADDR	0x70
+#define IVTV_Z8F0811_IR_RX_I2C_ADDR	0x71
+#define IVTV_ADAPTEC_IR_ADDR		0x6b
+
+/* This array should match the IVTV_HW_ defines */
+static const u8 hw_addrs[IVTV_HW_MAX_BITS] = {
+	IVTV_CX25840_I2C_ADDR,
+	IVTV_SAA7115_I2C_ADDR,
+	IVTV_SAA7127_I2C_ADDR,
+	IVTV_MSP3400_I2C_ADDR,
+	0,
+	IVTV_WM8775_I2C_ADDR,
+	IVTV_CS53L32A_I2C_ADDR,
+	0,
+	IVTV_SAA7115_I2C_ADDR,
+	IVTV_UPD64031A_I2C_ADDR,
+	IVTV_UPD64083_I2C_ADDR,
+	IVTV_SAA717x_I2C_ADDR,
+	IVTV_WM8739_I2C_ADDR,
+	IVTV_VP27SMPX_I2C_ADDR,
+	IVTV_M52790_I2C_ADDR,
+	0,				/* IVTV_HW_GPIO dummy driver ID */
+	IVTV_AVERMEDIA_IR_RX_I2C_ADDR,	/* IVTV_HW_I2C_IR_RX_AVER */
+	IVTV_HAUP_EXT_IR_RX_I2C_ADDR,	/* IVTV_HW_I2C_IR_RX_HAUP_EXT */
+	IVTV_HAUP_INT_IR_RX_I2C_ADDR,	/* IVTV_HW_I2C_IR_RX_HAUP_INT */
+	IVTV_Z8F0811_IR_RX_I2C_ADDR,	/* IVTV_HW_Z8F0811_IR_HAUP */
+	IVTV_ADAPTEC_IR_ADDR,		/* IVTV_HW_I2C_IR_RX_ADAPTEC */
+};
+
+/* This array should match the IVTV_HW_ defines */
+static const char * const hw_devicenames[IVTV_HW_MAX_BITS] = {
+	"cx25840",
+	"saa7115",
+	"saa7127_auto",	/* saa7127 or saa7129 */
+	"msp3400",
+	"tuner",
+	"wm8775",
+	"cs53l32a",
+	"tveeprom",
+	"saa7114",
+	"upd64031a",
+	"upd64083",
+	"saa717x",
+	"wm8739",
+	"vp27smpx",
+	"m52790",
+	"gpio",
+	"ir_video",		/* IVTV_HW_I2C_IR_RX_AVER */
+	"ir_video",		/* IVTV_HW_I2C_IR_RX_HAUP_EXT */
+	"ir_video",		/* IVTV_HW_I2C_IR_RX_HAUP_INT */
+	"ir_z8f0811_haup",	/* IVTV_HW_Z8F0811_IR_HAUP */
+	"ir_video",		/* IVTV_HW_I2C_IR_RX_ADAPTEC */
+};
+
+static int get_key_adaptec(struct IR_i2c *ir, enum rc_proto *protocol,
+			   u32 *scancode, u8 *toggle)
+{
+	unsigned char keybuf[4];
+
+	keybuf[0] = 0x00;
+	i2c_master_send(ir->c, keybuf, 1);
+	/* poll IR chip */
+	if (i2c_master_recv(ir->c, keybuf, sizeof(keybuf)) != sizeof(keybuf)) {
+		return 0;
+	}
+
+	/* key pressed ? */
+	if (keybuf[2] == 0xff)
+		return 0;
+
+	/* remove repeat bit */
+	keybuf[2] &= 0x7f;
+	keybuf[3] |= 0x80;
+
+	*protocol = RC_PROTO_UNKNOWN;
+	*scancode = keybuf[3] | keybuf[2] << 8 | keybuf[1] << 16 |keybuf[0] << 24;
+	*toggle = 0;
+	return 1;
+}
+
+static int ivtv_i2c_new_ir(struct ivtv *itv, u32 hw, const char *type, u8 addr)
+{
+	struct i2c_board_info info;
+	struct i2c_adapter *adap = &itv->i2c_adap;
+	struct IR_i2c_init_data *init_data = &itv->ir_i2c_init_data;
+	unsigned short addr_list[2] = { addr, I2C_CLIENT_END };
+
+	/* Only allow one IR receiver to be registered per board */
+	if (itv->hw_flags & IVTV_HW_IR_ANY)
+		return -1;
+
+	/* Our default information for ir-kbd-i2c.c to use */
+	switch (hw) {
+	case IVTV_HW_I2C_IR_RX_AVER:
+		init_data->ir_codes = RC_MAP_AVERMEDIA_CARDBUS;
+		init_data->internal_get_key_func =
+					IR_KBD_GET_KEY_AVERMEDIA_CARDBUS;
+		init_data->type = RC_PROTO_BIT_OTHER;
+		init_data->name = "AVerMedia AVerTV card";
+		break;
+	case IVTV_HW_I2C_IR_RX_HAUP_EXT:
+	case IVTV_HW_I2C_IR_RX_HAUP_INT:
+		init_data->ir_codes = RC_MAP_HAUPPAUGE;
+		init_data->internal_get_key_func = IR_KBD_GET_KEY_HAUP;
+		init_data->type = RC_PROTO_BIT_RC5;
+		init_data->name = itv->card_name;
+		break;
+	case IVTV_HW_Z8F0811_IR_HAUP:
+		/* Default to grey remote */
+		init_data->ir_codes = RC_MAP_HAUPPAUGE;
+		init_data->internal_get_key_func = IR_KBD_GET_KEY_HAUP_XVR;
+		init_data->type = RC_PROTO_BIT_RC5 | RC_PROTO_BIT_RC6_MCE |
+							RC_PROTO_BIT_RC6_6A_32;
+		init_data->name = itv->card_name;
+		break;
+	case IVTV_HW_I2C_IR_RX_ADAPTEC:
+		init_data->get_key = get_key_adaptec;
+		init_data->name = itv->card_name;
+		/* FIXME: The protocol and RC_MAP needs to be corrected */
+		init_data->ir_codes = RC_MAP_EMPTY;
+		init_data->type = RC_PROTO_BIT_UNKNOWN;
+		break;
+	}
+
+	memset(&info, 0, sizeof(struct i2c_board_info));
+	info.platform_data = init_data;
+	strscpy(info.type, type, I2C_NAME_SIZE);
+
+	return IS_ERR(i2c_new_scanned_device(adap, &info, addr_list, NULL)) ?
+	       -1 : 0;
+}
+
+/* Instantiate the IR receiver device using probing -- undesirable */
+void ivtv_i2c_new_ir_legacy(struct ivtv *itv)
+{
+	struct i2c_board_info info;
+	/*
+	 * The external IR receiver is at i2c address 0x34.
+	 * The internal IR receiver is at i2c address 0x30.
+	 *
+	 * In theory, both can be fitted, and Hauppauge suggests an external
+	 * overrides an internal.  That's why we probe 0x1a (~0x34) first. CB
+	 *
+	 * Some of these addresses we probe may collide with other i2c address
+	 * allocations, so this function must be called after all other i2c
+	 * devices we care about are registered.
+	 */
+	static const unsigned short addr_list[] = {
+		0x1a,	/* Hauppauge IR external - collides with WM8739 */
+		0x18,	/* Hauppauge IR internal */
+		I2C_CLIENT_END
+	};
+
+	memset(&info, 0, sizeof(struct i2c_board_info));
+	strscpy(info.type, "ir_video", I2C_NAME_SIZE);
+	i2c_new_scanned_device(&itv->i2c_adap, &info, addr_list, NULL);
+}
+
+int ivtv_i2c_register(struct ivtv *itv, unsigned idx)
+{
+	struct i2c_adapter *adap = &itv->i2c_adap;
+	struct v4l2_subdev *sd;
+	const char *type;
+	u32 hw;
+
+	if (idx >= IVTV_HW_MAX_BITS)
+		return -ENODEV;
+
+	type = hw_devicenames[idx];
+	hw = 1 << idx;
+
+	if (hw == IVTV_HW_TUNER) {
+		/* special tuner handling */
+		sd = v4l2_i2c_new_subdev(&itv->v4l2_dev, adap, type, 0,
+				itv->card_i2c->radio);
+		if (sd)
+			sd->grp_id = 1 << idx;
+		sd = v4l2_i2c_new_subdev(&itv->v4l2_dev, adap, type, 0,
+				itv->card_i2c->demod);
+		if (sd)
+			sd->grp_id = 1 << idx;
+		sd = v4l2_i2c_new_subdev(&itv->v4l2_dev, adap, type, 0,
+				itv->card_i2c->tv);
+		if (sd)
+			sd->grp_id = 1 << idx;
+		return sd ? 0 : -1;
+	}
+
+	if (hw & IVTV_HW_IR_ANY)
+		return ivtv_i2c_new_ir(itv, hw, type, hw_addrs[idx]);
+
+	/* Is it not an I2C device or one we do not wish to register? */
+	if (!hw_addrs[idx])
+		return -1;
+
+	/* It's an I2C device other than an analog tuner or IR chip */
+	if (hw == IVTV_HW_UPD64031A || hw == IVTV_HW_UPD6408X) {
+		sd = v4l2_i2c_new_subdev(&itv->v4l2_dev,
+				adap, type, 0, I2C_ADDRS(hw_addrs[idx]));
+	} else if (hw == IVTV_HW_CX25840) {
+		struct cx25840_platform_data pdata;
+		struct i2c_board_info cx25840_info = {
+			.type = "cx25840",
+			.addr = hw_addrs[idx],
+			.platform_data = &pdata,
+		};
+
+		memset(&pdata, 0, sizeof(pdata));
+		pdata.pvr150_workaround = itv->pvr150_workaround;
+		sd = v4l2_i2c_new_subdev_board(&itv->v4l2_dev, adap,
+				&cx25840_info, NULL);
+	} else {
+		sd = v4l2_i2c_new_subdev(&itv->v4l2_dev,
+				adap, type, hw_addrs[idx], NULL);
+	}
+	if (sd)
+		sd->grp_id = 1 << idx;
+	return sd ? 0 : -1;
+}
+
+struct v4l2_subdev *ivtv_find_hw(struct ivtv *itv, u32 hw)
+{
+	struct v4l2_subdev *result = NULL;
+	struct v4l2_subdev *sd;
+
+	spin_lock(&itv->v4l2_dev.lock);
+	v4l2_device_for_each_subdev(sd, &itv->v4l2_dev) {
+		if (sd->grp_id == hw) {
+			result = sd;
+			break;
+		}
+	}
+	spin_unlock(&itv->v4l2_dev.lock);
+	return result;
+}
+
+/* Set the serial clock line to the desired state */
+static void ivtv_setscl(struct ivtv *itv, int state)
+{
+	/* write them out */
+	/* write bits are inverted */
+	write_reg(~state, IVTV_REG_I2C_SETSCL_OFFSET);
+}
+
+/* Set the serial data line to the desired state */
+static void ivtv_setsda(struct ivtv *itv, int state)
+{
+	/* write them out */
+	/* write bits are inverted */
+	write_reg(~state & 1, IVTV_REG_I2C_SETSDA_OFFSET);
+}
+
+/* Read the serial clock line */
+static int ivtv_getscl(struct ivtv *itv)
+{
+	return read_reg(IVTV_REG_I2C_GETSCL_OFFSET) & 1;
+}
+
+/* Read the serial data line */
+static int ivtv_getsda(struct ivtv *itv)
+{
+	return read_reg(IVTV_REG_I2C_GETSDA_OFFSET) & 1;
+}
+
+/* Implement a short delay by polling the serial clock line */
+static void ivtv_scldelay(struct ivtv *itv)
+{
+	int i;
+
+	for (i = 0; i < 5; ++i)
+		ivtv_getscl(itv);
+}
+
+/* Wait for the serial clock line to become set to a specific value */
+static int ivtv_waitscl(struct ivtv *itv, int val)
+{
+	int i;
+
+	ivtv_scldelay(itv);
+	for (i = 0; i < 1000; ++i) {
+		if (ivtv_getscl(itv) == val)
+			return 1;
+	}
+	return 0;
+}
+
+/* Wait for the serial data line to become set to a specific value */
+static int ivtv_waitsda(struct ivtv *itv, int val)
+{
+	int i;
+
+	ivtv_scldelay(itv);
+	for (i = 0; i < 1000; ++i) {
+		if (ivtv_getsda(itv) == val)
+			return 1;
+	}
+	return 0;
+}
+
+/* Wait for the slave to issue an ACK */
+static int ivtv_ack(struct ivtv *itv)
+{
+	int ret = 0;
+
+	if (ivtv_getscl(itv) == 1) {
+		IVTV_DEBUG_HI_I2C("SCL was high starting an ack\n");
+		ivtv_setscl(itv, 0);
+		if (!ivtv_waitscl(itv, 0)) {
+			IVTV_DEBUG_I2C("Could not set SCL low starting an ack\n");
+			return -EREMOTEIO;
+		}
+	}
+	ivtv_setsda(itv, 1);
+	ivtv_scldelay(itv);
+	ivtv_setscl(itv, 1);
+	if (!ivtv_waitsda(itv, 0)) {
+		IVTV_DEBUG_I2C("Slave did not ack\n");
+		ret = -EREMOTEIO;
+	}
+	ivtv_setscl(itv, 0);
+	if (!ivtv_waitscl(itv, 0)) {
+		IVTV_DEBUG_I2C("Failed to set SCL low after ACK\n");
+		ret = -EREMOTEIO;
+	}
+	return ret;
+}
+
+/* Write a single byte to the i2c bus and wait for the slave to ACK */
+static int ivtv_sendbyte(struct ivtv *itv, unsigned char byte)
+{
+	int i, bit;
+
+	IVTV_DEBUG_HI_I2C("write %x\n",byte);
+	for (i = 0; i < 8; ++i, byte<<=1) {
+		ivtv_setscl(itv, 0);
+		if (!ivtv_waitscl(itv, 0)) {
+			IVTV_DEBUG_I2C("Error setting SCL low\n");
+			return -EREMOTEIO;
+		}
+		bit = (byte>>7)&1;
+		ivtv_setsda(itv, bit);
+		if (!ivtv_waitsda(itv, bit)) {
+			IVTV_DEBUG_I2C("Error setting SDA\n");
+			return -EREMOTEIO;
+		}
+		ivtv_setscl(itv, 1);
+		if (!ivtv_waitscl(itv, 1)) {
+			IVTV_DEBUG_I2C("Slave not ready for bit\n");
+			return -EREMOTEIO;
+		}
+	}
+	ivtv_setscl(itv, 0);
+	if (!ivtv_waitscl(itv, 0)) {
+		IVTV_DEBUG_I2C("Error setting SCL low\n");
+		return -EREMOTEIO;
+	}
+	return ivtv_ack(itv);
+}
+
+/* Read a byte from the i2c bus and send a NACK if applicable (i.e. for the
+   final byte) */
+static int ivtv_readbyte(struct ivtv *itv, unsigned char *byte, int nack)
+{
+	int i;
+
+	*byte = 0;
+
+	ivtv_setsda(itv, 1);
+	ivtv_scldelay(itv);
+	for (i = 0; i < 8; ++i) {
+		ivtv_setscl(itv, 0);
+		ivtv_scldelay(itv);
+		ivtv_setscl(itv, 1);
+		if (!ivtv_waitscl(itv, 1)) {
+			IVTV_DEBUG_I2C("Error setting SCL high\n");
+			return -EREMOTEIO;
+		}
+		*byte = ((*byte)<<1)|ivtv_getsda(itv);
+	}
+	ivtv_setscl(itv, 0);
+	ivtv_scldelay(itv);
+	ivtv_setsda(itv, nack);
+	ivtv_scldelay(itv);
+	ivtv_setscl(itv, 1);
+	ivtv_scldelay(itv);
+	ivtv_setscl(itv, 0);
+	ivtv_scldelay(itv);
+	IVTV_DEBUG_HI_I2C("read %x\n",*byte);
+	return 0;
+}
+
+/* Issue a start condition on the i2c bus to alert slaves to prepare for
+   an address write */
+static int ivtv_start(struct ivtv *itv)
+{
+	int sda;
+
+	sda = ivtv_getsda(itv);
+	if (sda != 1) {
+		IVTV_DEBUG_HI_I2C("SDA was low at start\n");
+		ivtv_setsda(itv, 1);
+		if (!ivtv_waitsda(itv, 1)) {
+			IVTV_DEBUG_I2C("SDA stuck low\n");
+			return -EREMOTEIO;
+		}
+	}
+	if (ivtv_getscl(itv) != 1) {
+		ivtv_setscl(itv, 1);
+		if (!ivtv_waitscl(itv, 1)) {
+			IVTV_DEBUG_I2C("SCL stuck low at start\n");
+			return -EREMOTEIO;
+		}
+	}
+	ivtv_setsda(itv, 0);
+	ivtv_scldelay(itv);
+	return 0;
+}
+
+/* Issue a stop condition on the i2c bus to release it */
+static int ivtv_stop(struct ivtv *itv)
+{
+	int i;
+
+	if (ivtv_getscl(itv) != 0) {
+		IVTV_DEBUG_HI_I2C("SCL not low when stopping\n");
+		ivtv_setscl(itv, 0);
+		if (!ivtv_waitscl(itv, 0)) {
+			IVTV_DEBUG_I2C("SCL could not be set low\n");
+		}
+	}
+	ivtv_setsda(itv, 0);
+	ivtv_scldelay(itv);
+	ivtv_setscl(itv, 1);
+	if (!ivtv_waitscl(itv, 1)) {
+		IVTV_DEBUG_I2C("SCL could not be set high\n");
+		return -EREMOTEIO;
+	}
+	ivtv_scldelay(itv);
+	ivtv_setsda(itv, 1);
+	if (!ivtv_waitsda(itv, 1)) {
+		IVTV_DEBUG_I2C("resetting I2C\n");
+		for (i = 0; i < 16; ++i) {
+			ivtv_setscl(itv, 0);
+			ivtv_scldelay(itv);
+			ivtv_setscl(itv, 1);
+			ivtv_scldelay(itv);
+			ivtv_setsda(itv, 1);
+		}
+		ivtv_waitsda(itv, 1);
+		return -EREMOTEIO;
+	}
+	return 0;
+}
+
+/* Write a message to the given i2c slave.  do_stop may be 0 to prevent
+   issuing the i2c stop condition (when following with a read) */
+static int ivtv_write(struct ivtv *itv, unsigned char addr, unsigned char *data, u32 len, int do_stop)
+{
+	int retry, ret = -EREMOTEIO;
+	u32 i;
+
+	for (retry = 0; ret != 0 && retry < 8; ++retry) {
+		ret = ivtv_start(itv);
+
+		if (ret == 0) {
+			ret = ivtv_sendbyte(itv, addr<<1);
+			for (i = 0; ret == 0 && i < len; ++i)
+				ret = ivtv_sendbyte(itv, data[i]);
+		}
+		if (ret != 0 || do_stop) {
+			ivtv_stop(itv);
+		}
+	}
+	if (ret)
+		IVTV_DEBUG_I2C("i2c write to %x failed\n", addr);
+	return ret;
+}
+
+/* Read data from the given i2c slave.  A stop condition is always issued. */
+static int ivtv_read(struct ivtv *itv, unsigned char addr, unsigned char *data, u32 len)
+{
+	int retry, ret = -EREMOTEIO;
+	u32 i;
+
+	for (retry = 0; ret != 0 && retry < 8; ++retry) {
+		ret = ivtv_start(itv);
+		if (ret == 0)
+			ret = ivtv_sendbyte(itv, (addr << 1) | 1);
+		for (i = 0; ret == 0 && i < len; ++i) {
+			ret = ivtv_readbyte(itv, &data[i], i == len - 1);
+		}
+		ivtv_stop(itv);
+	}
+	if (ret)
+		IVTV_DEBUG_I2C("i2c read from %x failed\n", addr);
+	return ret;
+}
+
+/* Kernel i2c transfer implementation.  Takes a number of messages to be read
+   or written.  If a read follows a write, this will occur without an
+   intervening stop condition */
+static int ivtv_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
+{
+	struct v4l2_device *v4l2_dev = i2c_get_adapdata(i2c_adap);
+	struct ivtv *itv = to_ivtv(v4l2_dev);
+	int retval;
+	int i;
+
+	mutex_lock(&itv->i2c_bus_lock);
+	for (i = retval = 0; retval == 0 && i < num; i++) {
+		if (msgs[i].flags & I2C_M_RD)
+			retval = ivtv_read(itv, msgs[i].addr, msgs[i].buf, msgs[i].len);
+		else {
+			/* if followed by a read, don't stop */
+			int stop = !(i + 1 < num && msgs[i + 1].flags == I2C_M_RD);
+
+			retval = ivtv_write(itv, msgs[i].addr, msgs[i].buf, msgs[i].len, stop);
+		}
+	}
+	mutex_unlock(&itv->i2c_bus_lock);
+	return retval ? retval : num;
+}
+
+/* Kernel i2c capabilities */
+static u32 ivtv_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm ivtv_algo = {
+	.master_xfer   = ivtv_xfer,
+	.functionality = ivtv_functionality,
+};
+
+/* template for our-bit banger */
+static const struct i2c_adapter ivtv_i2c_adap_hw_template = {
+	.name = "ivtv i2c driver",
+	.algo = &ivtv_algo,
+	.algo_data = NULL,			/* filled from template */
+	.owner = THIS_MODULE,
+};
+
+static void ivtv_setscl_old(void *data, int state)
+{
+	struct ivtv *itv = (struct ivtv *)data;
+
+	if (state)
+		itv->i2c_state |= 0x01;
+	else
+		itv->i2c_state &= ~0x01;
+
+	/* write them out */
+	/* write bits are inverted */
+	write_reg(~itv->i2c_state, IVTV_REG_I2C_SETSCL_OFFSET);
+}
+
+static void ivtv_setsda_old(void *data, int state)
+{
+	struct ivtv *itv = (struct ivtv *)data;
+
+	if (state)
+		itv->i2c_state |= 0x01;
+	else
+		itv->i2c_state &= ~0x01;
+
+	/* write them out */
+	/* write bits are inverted */
+	write_reg(~itv->i2c_state, IVTV_REG_I2C_SETSDA_OFFSET);
+}
+
+static int ivtv_getscl_old(void *data)
+{
+	struct ivtv *itv = (struct ivtv *)data;
+
+	return read_reg(IVTV_REG_I2C_GETSCL_OFFSET) & 1;
+}
+
+static int ivtv_getsda_old(void *data)
+{
+	struct ivtv *itv = (struct ivtv *)data;
+
+	return read_reg(IVTV_REG_I2C_GETSDA_OFFSET) & 1;
+}
+
+/* template for i2c-bit-algo */
+static const struct i2c_adapter ivtv_i2c_adap_template = {
+	.name = "ivtv i2c driver",
+	.algo = NULL,                   /* set by i2c-algo-bit */
+	.algo_data = NULL,              /* filled from template */
+	.owner = THIS_MODULE,
+};
+
+#define IVTV_ALGO_BIT_TIMEOUT	(2)	/* seconds */
+
+static const struct i2c_algo_bit_data ivtv_i2c_algo_template = {
+	.setsda		= ivtv_setsda_old,
+	.setscl		= ivtv_setscl_old,
+	.getsda		= ivtv_getsda_old,
+	.getscl		= ivtv_getscl_old,
+	.udelay		= IVTV_DEFAULT_I2C_CLOCK_PERIOD / 2,  /* microseconds */
+	.timeout	= IVTV_ALGO_BIT_TIMEOUT * HZ,         /* jiffies */
+};
+
+static const struct i2c_client ivtv_i2c_client_template = {
+	.name = "ivtv internal",
+};
+
+/* init + register i2c adapter */
+int init_ivtv_i2c(struct ivtv *itv)
+{
+	int retval;
+
+	IVTV_DEBUG_I2C("i2c init\n");
+
+	/* Sanity checks for the I2C hardware arrays. They must be the
+	 * same size.
+	 */
+	if (ARRAY_SIZE(hw_devicenames) != ARRAY_SIZE(hw_addrs)) {
+		IVTV_ERR("Mismatched I2C hardware arrays\n");
+		return -ENODEV;
+	}
+	if (itv->options.newi2c > 0) {
+		itv->i2c_adap = ivtv_i2c_adap_hw_template;
+	} else {
+		itv->i2c_adap = ivtv_i2c_adap_template;
+		itv->i2c_algo = ivtv_i2c_algo_template;
+	}
+	itv->i2c_algo.udelay = itv->options.i2c_clock_period / 2;
+	itv->i2c_algo.data = itv;
+	itv->i2c_adap.algo_data = &itv->i2c_algo;
+
+	sprintf(itv->i2c_adap.name + strlen(itv->i2c_adap.name), " #%d",
+		itv->instance);
+	i2c_set_adapdata(&itv->i2c_adap, &itv->v4l2_dev);
+
+	itv->i2c_client = ivtv_i2c_client_template;
+	itv->i2c_client.adapter = &itv->i2c_adap;
+	itv->i2c_adap.dev.parent = &itv->pdev->dev;
+
+	IVTV_DEBUG_I2C("setting scl and sda to 1\n");
+	ivtv_setscl(itv, 1);
+	ivtv_setsda(itv, 1);
+
+	if (itv->options.newi2c > 0)
+		retval = i2c_add_adapter(&itv->i2c_adap);
+	else
+		retval = i2c_bit_add_bus(&itv->i2c_adap);
+
+	return retval;
+}
+
+void exit_ivtv_i2c(struct ivtv *itv)
+{
+	IVTV_DEBUG_I2C("i2c exit\n");
+
+	i2c_del_adapter(&itv->i2c_adap);
+}