3 Copyright (C) 2003-2004 Kevin Thayer <nufan_wfk at yahoo.com>
4 Copyright (C) 2005-2007 Hans Verkuil <hverkuil@xs4all.nl>
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 This file includes an i2c implementation that was reverse engineered
23 from the Hauppauge windows driver. Older ivtv versions used i2c-algo-bit,
24 which whilst fine under most circumstances, had trouble with the Zilog
25 CPU on the PVR-150 which handles IR functions (occasional inability to
26 communicate with the chip until it was reset) and also with the i2c
27 bus being completely unreachable when multiple PVR cards were present.
29 The implementation is very similar to i2c-algo-bit, but there are enough
30 subtle differences that the two are hard to merge. The general strategy
31 employed by i2c-algo-bit is to use udelay() to implement the timing
32 when putting out bits on the scl/sda lines. The general strategy taken
33 here is to poll the lines for state changes (see ivtv_waitscl and
34 ivtv_waitsda). In addition there are small delays at various locations
35 which poll the SCL line 5 times (ivtv_scldelay). I would guess that
36 since this is memory mapped I/O that the length of those delays is tied
37 to the PCI bus clock. There is some extra code to do with recovery
38 and retries. Since it is not known what causes the actual i2c problems
39 in the first place, the only goal if one was to attempt to use
40 i2c-algo-bit would be to try to make it follow the same code path.
41 This would be a lot of work, and I'm also not convinced that it would
42 provide a generic benefit to i2c-algo-bit. Therefore consider this
43 an engineering solution -- not pretty, but it works.
45 Some more general comments about what we are doing:
47 The i2c bus is a 2 wire serial bus, with clock (SCL) and data (SDA)
48 lines. To communicate on the bus (as a master, we don't act as a slave),
49 we first initiate a start condition (ivtv_start). We then write the
50 address of the device that we want to communicate with, along with a flag
51 that indicates whether this is a read or a write. The slave then issues
52 an ACK signal (ivtv_ack), which tells us that it is ready for reading /
53 writing. We then proceed with reading or writing (ivtv_read/ivtv_write),
54 and finally issue a stop condition (ivtv_stop) to make the bus available
57 There is an additional form of transaction where a write may be
58 immediately followed by a read. In this case, there is no intervening
59 stop condition. (Only the msp3400 chip uses this method of data transfer).
62 #include "ivtv-driver.h"
63 #include "ivtv-cards.h"
64 #include "ivtv-gpio.h"
67 /* i2c implementation for cx23415/6 chip, ivtv project.
68 * Author: Kevin Thayer (nufan_wfk at yahoo.com)
71 #define IVTV_REG_I2C_SETSCL_OFFSET 0x7000
72 #define IVTV_REG_I2C_SETSDA_OFFSET 0x7004
73 #define IVTV_REG_I2C_GETSCL_OFFSET 0x7008
74 #define IVTV_REG_I2C_GETSDA_OFFSET 0x700c
76 #define IVTV_CS53L32A_I2C_ADDR 0x11
77 #define IVTV_M52790_I2C_ADDR 0x48
78 #define IVTV_CX25840_I2C_ADDR 0x44
79 #define IVTV_SAA7115_I2C_ADDR 0x21
80 #define IVTV_SAA7127_I2C_ADDR 0x44
81 #define IVTV_SAA717x_I2C_ADDR 0x21
82 #define IVTV_MSP3400_I2C_ADDR 0x40
83 #define IVTV_HAUPPAUGE_I2C_ADDR 0x50
84 #define IVTV_WM8739_I2C_ADDR 0x1a
85 #define IVTV_WM8775_I2C_ADDR 0x1b
86 #define IVTV_TEA5767_I2C_ADDR 0x60
87 #define IVTV_UPD64031A_I2C_ADDR 0x12
88 #define IVTV_UPD64083_I2C_ADDR 0x5c
89 #define IVTV_VP27SMPX_I2C_ADDR 0x5b
90 #define IVTV_M52790_I2C_ADDR 0x48
92 /* This array should match the IVTV_HW_ defines */
93 static const u8 hw_addrs[] = {
94 IVTV_CX25840_I2C_ADDR,
95 IVTV_SAA7115_I2C_ADDR,
96 IVTV_SAA7127_I2C_ADDR,
97 IVTV_MSP3400_I2C_ADDR,
100 IVTV_CS53L32A_I2C_ADDR,
102 IVTV_SAA7115_I2C_ADDR,
103 IVTV_UPD64031A_I2C_ADDR,
104 IVTV_UPD64083_I2C_ADDR,
105 IVTV_SAA717x_I2C_ADDR,
106 IVTV_WM8739_I2C_ADDR,
107 IVTV_VP27SMPX_I2C_ADDR,
108 IVTV_M52790_I2C_ADDR,
109 0 /* IVTV_HW_GPIO dummy driver ID */
112 /* This array should match the IVTV_HW_ defines */
113 static const char *hw_modules[] = {
132 /* This array should match the IVTV_HW_ defines */
133 static const char * const hw_devicenames[] = {
136 "saa7127_auto", /* saa7127 or saa7129 */
152 int ivtv_i2c_register(struct ivtv *itv, unsigned idx)
154 struct v4l2_subdev *sd;
155 struct i2c_adapter *adap = &itv->i2c_adap;
156 const char *mod = hw_modules[idx];
157 const char *type = hw_devicenames[idx];
160 if (idx >= ARRAY_SIZE(hw_addrs))
162 if (hw == IVTV_HW_TUNER) {
163 /* special tuner handling */
164 sd = v4l2_i2c_new_probed_subdev(adap, mod, type,
165 itv->card_i2c->radio);
167 sd->grp_id = 1 << idx;
168 sd = v4l2_i2c_new_probed_subdev(adap, mod, type,
169 itv->card_i2c->demod);
171 sd->grp_id = 1 << idx;
172 sd = v4l2_i2c_new_probed_subdev(adap, mod, type,
175 sd->grp_id = 1 << idx;
180 if (hw == IVTV_HW_UPD64031A || hw == IVTV_HW_UPD6408X) {
181 unsigned short addrs[2] = { hw_addrs[idx], I2C_CLIENT_END };
183 sd = v4l2_i2c_new_probed_subdev(adap, mod, type, addrs);
185 sd = v4l2_i2c_new_subdev(adap, mod, type, hw_addrs[idx]);
188 sd->grp_id = 1 << idx;
192 struct v4l2_subdev *ivtv_find_hw(struct ivtv *itv, u32 hw)
194 struct v4l2_subdev *result = NULL;
195 struct v4l2_subdev *sd;
197 spin_lock(&itv->device.lock);
198 v4l2_device_for_each_subdev(sd, &itv->device) {
199 if (sd->grp_id == hw) {
204 spin_unlock(&itv->device.lock);
208 /* Set the serial clock line to the desired state */
209 static void ivtv_setscl(struct ivtv *itv, int state)
212 /* write bits are inverted */
213 write_reg(~state, IVTV_REG_I2C_SETSCL_OFFSET);
216 /* Set the serial data line to the desired state */
217 static void ivtv_setsda(struct ivtv *itv, int state)
220 /* write bits are inverted */
221 write_reg(~state & 1, IVTV_REG_I2C_SETSDA_OFFSET);
224 /* Read the serial clock line */
225 static int ivtv_getscl(struct ivtv *itv)
227 return read_reg(IVTV_REG_I2C_GETSCL_OFFSET) & 1;
230 /* Read the serial data line */
231 static int ivtv_getsda(struct ivtv *itv)
233 return read_reg(IVTV_REG_I2C_GETSDA_OFFSET) & 1;
236 /* Implement a short delay by polling the serial clock line */
237 static void ivtv_scldelay(struct ivtv *itv)
241 for (i = 0; i < 5; ++i)
245 /* Wait for the serial clock line to become set to a specific value */
246 static int ivtv_waitscl(struct ivtv *itv, int val)
251 for (i = 0; i < 1000; ++i) {
252 if (ivtv_getscl(itv) == val)
258 /* Wait for the serial data line to become set to a specific value */
259 static int ivtv_waitsda(struct ivtv *itv, int val)
264 for (i = 0; i < 1000; ++i) {
265 if (ivtv_getsda(itv) == val)
271 /* Wait for the slave to issue an ACK */
272 static int ivtv_ack(struct ivtv *itv)
276 if (ivtv_getscl(itv) == 1) {
277 IVTV_DEBUG_HI_I2C("SCL was high starting an ack\n");
279 if (!ivtv_waitscl(itv, 0)) {
280 IVTV_DEBUG_I2C("Could not set SCL low starting an ack\n");
287 if (!ivtv_waitsda(itv, 0)) {
288 IVTV_DEBUG_I2C("Slave did not ack\n");
292 if (!ivtv_waitscl(itv, 0)) {
293 IVTV_DEBUG_I2C("Failed to set SCL low after ACK\n");
299 /* Write a single byte to the i2c bus and wait for the slave to ACK */
300 static int ivtv_sendbyte(struct ivtv *itv, unsigned char byte)
304 IVTV_DEBUG_HI_I2C("write %x\n",byte);
305 for (i = 0; i < 8; ++i, byte<<=1) {
307 if (!ivtv_waitscl(itv, 0)) {
308 IVTV_DEBUG_I2C("Error setting SCL low\n");
312 ivtv_setsda(itv, bit);
313 if (!ivtv_waitsda(itv, bit)) {
314 IVTV_DEBUG_I2C("Error setting SDA\n");
318 if (!ivtv_waitscl(itv, 1)) {
319 IVTV_DEBUG_I2C("Slave not ready for bit\n");
324 if (!ivtv_waitscl(itv, 0)) {
325 IVTV_DEBUG_I2C("Error setting SCL low\n");
328 return ivtv_ack(itv);
331 /* Read a byte from the i2c bus and send a NACK if applicable (i.e. for the
333 static int ivtv_readbyte(struct ivtv *itv, unsigned char *byte, int nack)
341 for (i = 0; i < 8; ++i) {
345 if (!ivtv_waitscl(itv, 1)) {
346 IVTV_DEBUG_I2C("Error setting SCL high\n");
349 *byte = ((*byte)<<1)|ivtv_getsda(itv);
353 ivtv_setsda(itv, nack);
359 IVTV_DEBUG_HI_I2C("read %x\n",*byte);
363 /* Issue a start condition on the i2c bus to alert slaves to prepare for
365 static int ivtv_start(struct ivtv *itv)
369 sda = ivtv_getsda(itv);
371 IVTV_DEBUG_HI_I2C("SDA was low at start\n");
373 if (!ivtv_waitsda(itv, 1)) {
374 IVTV_DEBUG_I2C("SDA stuck low\n");
378 if (ivtv_getscl(itv) != 1) {
380 if (!ivtv_waitscl(itv, 1)) {
381 IVTV_DEBUG_I2C("SCL stuck low at start\n");
390 /* Issue a stop condition on the i2c bus to release it */
391 static int ivtv_stop(struct ivtv *itv)
395 if (ivtv_getscl(itv) != 0) {
396 IVTV_DEBUG_HI_I2C("SCL not low when stopping\n");
398 if (!ivtv_waitscl(itv, 0)) {
399 IVTV_DEBUG_I2C("SCL could not be set low\n");
405 if (!ivtv_waitscl(itv, 1)) {
406 IVTV_DEBUG_I2C("SCL could not be set high\n");
411 if (!ivtv_waitsda(itv, 1)) {
412 IVTV_DEBUG_I2C("resetting I2C\n");
413 for (i = 0; i < 16; ++i) {
420 ivtv_waitsda(itv, 1);
426 /* Write a message to the given i2c slave. do_stop may be 0 to prevent
427 issuing the i2c stop condition (when following with a read) */
428 static int ivtv_write(struct ivtv *itv, unsigned char addr, unsigned char *data, u32 len, int do_stop)
430 int retry, ret = -EREMOTEIO;
433 for (retry = 0; ret != 0 && retry < 8; ++retry) {
434 ret = ivtv_start(itv);
437 ret = ivtv_sendbyte(itv, addr<<1);
438 for (i = 0; ret == 0 && i < len; ++i)
439 ret = ivtv_sendbyte(itv, data[i]);
441 if (ret != 0 || do_stop) {
446 IVTV_DEBUG_I2C("i2c write to %x failed\n", addr);
450 /* Read data from the given i2c slave. A stop condition is always issued. */
451 static int ivtv_read(struct ivtv *itv, unsigned char addr, unsigned char *data, u32 len)
453 int retry, ret = -EREMOTEIO;
456 for (retry = 0; ret != 0 && retry < 8; ++retry) {
457 ret = ivtv_start(itv);
459 ret = ivtv_sendbyte(itv, (addr << 1) | 1);
460 for (i = 0; ret == 0 && i < len; ++i) {
461 ret = ivtv_readbyte(itv, &data[i], i == len - 1);
466 IVTV_DEBUG_I2C("i2c read from %x failed\n", addr);
470 /* Kernel i2c transfer implementation. Takes a number of messages to be read
471 or written. If a read follows a write, this will occur without an
472 intervening stop condition */
473 static int ivtv_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
475 struct v4l2_device *drv = i2c_get_adapdata(i2c_adap);
476 struct ivtv *itv = to_ivtv(drv);
480 mutex_lock(&itv->i2c_bus_lock);
481 for (i = retval = 0; retval == 0 && i < num; i++) {
482 if (msgs[i].flags & I2C_M_RD)
483 retval = ivtv_read(itv, msgs[i].addr, msgs[i].buf, msgs[i].len);
485 /* if followed by a read, don't stop */
486 int stop = !(i + 1 < num && msgs[i + 1].flags == I2C_M_RD);
488 retval = ivtv_write(itv, msgs[i].addr, msgs[i].buf, msgs[i].len, stop);
491 mutex_unlock(&itv->i2c_bus_lock);
492 return retval ? retval : num;
495 /* Kernel i2c capabilities */
496 static u32 ivtv_functionality(struct i2c_adapter *adap)
498 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
501 static struct i2c_algorithm ivtv_algo = {
502 .master_xfer = ivtv_xfer,
503 .functionality = ivtv_functionality,
506 /* template for our-bit banger */
507 static struct i2c_adapter ivtv_i2c_adap_hw_template = {
508 .name = "ivtv i2c driver",
509 .id = I2C_HW_B_CX2341X,
511 .algo_data = NULL, /* filled from template */
512 .owner = THIS_MODULE,
515 static void ivtv_setscl_old(void *data, int state)
517 struct ivtv *itv = (struct ivtv *)data;
520 itv->i2c_state |= 0x01;
522 itv->i2c_state &= ~0x01;
525 /* write bits are inverted */
526 write_reg(~itv->i2c_state, IVTV_REG_I2C_SETSCL_OFFSET);
529 static void ivtv_setsda_old(void *data, int state)
531 struct ivtv *itv = (struct ivtv *)data;
534 itv->i2c_state |= 0x01;
536 itv->i2c_state &= ~0x01;
539 /* write bits are inverted */
540 write_reg(~itv->i2c_state, IVTV_REG_I2C_SETSDA_OFFSET);
543 static int ivtv_getscl_old(void *data)
545 struct ivtv *itv = (struct ivtv *)data;
547 return read_reg(IVTV_REG_I2C_GETSCL_OFFSET) & 1;
550 static int ivtv_getsda_old(void *data)
552 struct ivtv *itv = (struct ivtv *)data;
554 return read_reg(IVTV_REG_I2C_GETSDA_OFFSET) & 1;
557 /* template for i2c-bit-algo */
558 static struct i2c_adapter ivtv_i2c_adap_template = {
559 .name = "ivtv i2c driver",
560 .id = I2C_HW_B_CX2341X,
561 .algo = NULL, /* set by i2c-algo-bit */
562 .algo_data = NULL, /* filled from template */
563 .owner = THIS_MODULE,
566 static const struct i2c_algo_bit_data ivtv_i2c_algo_template = {
567 .setsda = ivtv_setsda_old,
568 .setscl = ivtv_setscl_old,
569 .getsda = ivtv_getsda_old,
570 .getscl = ivtv_getscl_old,
575 static struct i2c_client ivtv_i2c_client_template = {
576 .name = "ivtv internal",
579 /* init + register i2c algo-bit adapter */
580 int init_ivtv_i2c(struct ivtv *itv)
582 IVTV_DEBUG_I2C("i2c init\n");
584 /* Sanity checks for the I2C hardware arrays. They must be the
585 * same size and GPIO must be the last entry.
587 if (ARRAY_SIZE(hw_devicenames) != ARRAY_SIZE(hw_addrs) ||
588 ARRAY_SIZE(hw_devicenames) != ARRAY_SIZE(hw_modules) ||
589 IVTV_HW_GPIO != (1 << (ARRAY_SIZE(hw_addrs) - 1))) {
590 IVTV_ERR("Mismatched I2C hardware arrays\n");
593 if (itv->options.newi2c > 0) {
594 memcpy(&itv->i2c_adap, &ivtv_i2c_adap_hw_template,
595 sizeof(struct i2c_adapter));
597 memcpy(&itv->i2c_adap, &ivtv_i2c_adap_template,
598 sizeof(struct i2c_adapter));
599 memcpy(&itv->i2c_algo, &ivtv_i2c_algo_template,
600 sizeof(struct i2c_algo_bit_data));
602 itv->i2c_algo.data = itv;
603 itv->i2c_adap.algo_data = &itv->i2c_algo;
605 sprintf(itv->i2c_adap.name + strlen(itv->i2c_adap.name), " #%d",
607 i2c_set_adapdata(&itv->i2c_adap, &itv->device);
609 memcpy(&itv->i2c_client, &ivtv_i2c_client_template,
610 sizeof(struct i2c_client));
611 itv->i2c_client.adapter = &itv->i2c_adap;
612 itv->i2c_adap.dev.parent = &itv->dev->dev;
614 IVTV_DEBUG_I2C("setting scl and sda to 1\n");
618 if (itv->options.newi2c > 0)
619 return i2c_add_adapter(&itv->i2c_adap);
621 return i2c_bit_add_bus(&itv->i2c_adap);
624 void exit_ivtv_i2c(struct ivtv *itv)
626 IVTV_DEBUG_I2C("i2c exit\n");
628 i2c_del_adapter(&itv->i2c_adap);