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(&itv->v4l2_dev,
166 itv->card_i2c->radio);
168 sd->grp_id = 1 << idx;
169 sd = v4l2_i2c_new_probed_subdev(&itv->v4l2_dev,
171 itv->card_i2c->demod);
173 sd->grp_id = 1 << idx;
174 sd = v4l2_i2c_new_probed_subdev(&itv->v4l2_dev,
178 sd->grp_id = 1 << idx;
183 if (hw == IVTV_HW_UPD64031A || hw == IVTV_HW_UPD6408X) {
184 sd = v4l2_i2c_new_probed_subdev_addr(&itv->v4l2_dev,
185 adap, mod, type, hw_addrs[idx]);
187 sd = v4l2_i2c_new_subdev(&itv->v4l2_dev,
188 adap, mod, type, hw_addrs[idx]);
191 sd->grp_id = 1 << idx;
195 struct v4l2_subdev *ivtv_find_hw(struct ivtv *itv, u32 hw)
197 struct v4l2_subdev *result = NULL;
198 struct v4l2_subdev *sd;
200 spin_lock(&itv->v4l2_dev.lock);
201 v4l2_device_for_each_subdev(sd, &itv->v4l2_dev) {
202 if (sd->grp_id == hw) {
207 spin_unlock(&itv->v4l2_dev.lock);
211 /* Set the serial clock line to the desired state */
212 static void ivtv_setscl(struct ivtv *itv, int state)
215 /* write bits are inverted */
216 write_reg(~state, IVTV_REG_I2C_SETSCL_OFFSET);
219 /* Set the serial data line to the desired state */
220 static void ivtv_setsda(struct ivtv *itv, int state)
223 /* write bits are inverted */
224 write_reg(~state & 1, IVTV_REG_I2C_SETSDA_OFFSET);
227 /* Read the serial clock line */
228 static int ivtv_getscl(struct ivtv *itv)
230 return read_reg(IVTV_REG_I2C_GETSCL_OFFSET) & 1;
233 /* Read the serial data line */
234 static int ivtv_getsda(struct ivtv *itv)
236 return read_reg(IVTV_REG_I2C_GETSDA_OFFSET) & 1;
239 /* Implement a short delay by polling the serial clock line */
240 static void ivtv_scldelay(struct ivtv *itv)
244 for (i = 0; i < 5; ++i)
248 /* Wait for the serial clock line to become set to a specific value */
249 static int ivtv_waitscl(struct ivtv *itv, int val)
254 for (i = 0; i < 1000; ++i) {
255 if (ivtv_getscl(itv) == val)
261 /* Wait for the serial data line to become set to a specific value */
262 static int ivtv_waitsda(struct ivtv *itv, int val)
267 for (i = 0; i < 1000; ++i) {
268 if (ivtv_getsda(itv) == val)
274 /* Wait for the slave to issue an ACK */
275 static int ivtv_ack(struct ivtv *itv)
279 if (ivtv_getscl(itv) == 1) {
280 IVTV_DEBUG_HI_I2C("SCL was high starting an ack\n");
282 if (!ivtv_waitscl(itv, 0)) {
283 IVTV_DEBUG_I2C("Could not set SCL low starting an ack\n");
290 if (!ivtv_waitsda(itv, 0)) {
291 IVTV_DEBUG_I2C("Slave did not ack\n");
295 if (!ivtv_waitscl(itv, 0)) {
296 IVTV_DEBUG_I2C("Failed to set SCL low after ACK\n");
302 /* Write a single byte to the i2c bus and wait for the slave to ACK */
303 static int ivtv_sendbyte(struct ivtv *itv, unsigned char byte)
307 IVTV_DEBUG_HI_I2C("write %x\n",byte);
308 for (i = 0; i < 8; ++i, byte<<=1) {
310 if (!ivtv_waitscl(itv, 0)) {
311 IVTV_DEBUG_I2C("Error setting SCL low\n");
315 ivtv_setsda(itv, bit);
316 if (!ivtv_waitsda(itv, bit)) {
317 IVTV_DEBUG_I2C("Error setting SDA\n");
321 if (!ivtv_waitscl(itv, 1)) {
322 IVTV_DEBUG_I2C("Slave not ready for bit\n");
327 if (!ivtv_waitscl(itv, 0)) {
328 IVTV_DEBUG_I2C("Error setting SCL low\n");
331 return ivtv_ack(itv);
334 /* Read a byte from the i2c bus and send a NACK if applicable (i.e. for the
336 static int ivtv_readbyte(struct ivtv *itv, unsigned char *byte, int nack)
344 for (i = 0; i < 8; ++i) {
348 if (!ivtv_waitscl(itv, 1)) {
349 IVTV_DEBUG_I2C("Error setting SCL high\n");
352 *byte = ((*byte)<<1)|ivtv_getsda(itv);
356 ivtv_setsda(itv, nack);
362 IVTV_DEBUG_HI_I2C("read %x\n",*byte);
366 /* Issue a start condition on the i2c bus to alert slaves to prepare for
368 static int ivtv_start(struct ivtv *itv)
372 sda = ivtv_getsda(itv);
374 IVTV_DEBUG_HI_I2C("SDA was low at start\n");
376 if (!ivtv_waitsda(itv, 1)) {
377 IVTV_DEBUG_I2C("SDA stuck low\n");
381 if (ivtv_getscl(itv) != 1) {
383 if (!ivtv_waitscl(itv, 1)) {
384 IVTV_DEBUG_I2C("SCL stuck low at start\n");
393 /* Issue a stop condition on the i2c bus to release it */
394 static int ivtv_stop(struct ivtv *itv)
398 if (ivtv_getscl(itv) != 0) {
399 IVTV_DEBUG_HI_I2C("SCL not low when stopping\n");
401 if (!ivtv_waitscl(itv, 0)) {
402 IVTV_DEBUG_I2C("SCL could not be set low\n");
408 if (!ivtv_waitscl(itv, 1)) {
409 IVTV_DEBUG_I2C("SCL could not be set high\n");
414 if (!ivtv_waitsda(itv, 1)) {
415 IVTV_DEBUG_I2C("resetting I2C\n");
416 for (i = 0; i < 16; ++i) {
423 ivtv_waitsda(itv, 1);
429 /* Write a message to the given i2c slave. do_stop may be 0 to prevent
430 issuing the i2c stop condition (when following with a read) */
431 static int ivtv_write(struct ivtv *itv, unsigned char addr, unsigned char *data, u32 len, int do_stop)
433 int retry, ret = -EREMOTEIO;
436 for (retry = 0; ret != 0 && retry < 8; ++retry) {
437 ret = ivtv_start(itv);
440 ret = ivtv_sendbyte(itv, addr<<1);
441 for (i = 0; ret == 0 && i < len; ++i)
442 ret = ivtv_sendbyte(itv, data[i]);
444 if (ret != 0 || do_stop) {
449 IVTV_DEBUG_I2C("i2c write to %x failed\n", addr);
453 /* Read data from the given i2c slave. A stop condition is always issued. */
454 static int ivtv_read(struct ivtv *itv, unsigned char addr, unsigned char *data, u32 len)
456 int retry, ret = -EREMOTEIO;
459 for (retry = 0; ret != 0 && retry < 8; ++retry) {
460 ret = ivtv_start(itv);
462 ret = ivtv_sendbyte(itv, (addr << 1) | 1);
463 for (i = 0; ret == 0 && i < len; ++i) {
464 ret = ivtv_readbyte(itv, &data[i], i == len - 1);
469 IVTV_DEBUG_I2C("i2c read from %x failed\n", addr);
473 /* Kernel i2c transfer implementation. Takes a number of messages to be read
474 or written. If a read follows a write, this will occur without an
475 intervening stop condition */
476 static int ivtv_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
478 struct v4l2_device *v4l2_dev = i2c_get_adapdata(i2c_adap);
479 struct ivtv *itv = to_ivtv(v4l2_dev);
483 mutex_lock(&itv->i2c_bus_lock);
484 for (i = retval = 0; retval == 0 && i < num; i++) {
485 if (msgs[i].flags & I2C_M_RD)
486 retval = ivtv_read(itv, msgs[i].addr, msgs[i].buf, msgs[i].len);
488 /* if followed by a read, don't stop */
489 int stop = !(i + 1 < num && msgs[i + 1].flags == I2C_M_RD);
491 retval = ivtv_write(itv, msgs[i].addr, msgs[i].buf, msgs[i].len, stop);
494 mutex_unlock(&itv->i2c_bus_lock);
495 return retval ? retval : num;
498 /* Kernel i2c capabilities */
499 static u32 ivtv_functionality(struct i2c_adapter *adap)
501 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
504 static struct i2c_algorithm ivtv_algo = {
505 .master_xfer = ivtv_xfer,
506 .functionality = ivtv_functionality,
509 /* template for our-bit banger */
510 static struct i2c_adapter ivtv_i2c_adap_hw_template = {
511 .name = "ivtv i2c driver",
512 .id = I2C_HW_B_CX2341X,
514 .algo_data = NULL, /* filled from template */
515 .owner = THIS_MODULE,
518 static void ivtv_setscl_old(void *data, int state)
520 struct ivtv *itv = (struct ivtv *)data;
523 itv->i2c_state |= 0x01;
525 itv->i2c_state &= ~0x01;
528 /* write bits are inverted */
529 write_reg(~itv->i2c_state, IVTV_REG_I2C_SETSCL_OFFSET);
532 static void ivtv_setsda_old(void *data, int state)
534 struct ivtv *itv = (struct ivtv *)data;
537 itv->i2c_state |= 0x01;
539 itv->i2c_state &= ~0x01;
542 /* write bits are inverted */
543 write_reg(~itv->i2c_state, IVTV_REG_I2C_SETSDA_OFFSET);
546 static int ivtv_getscl_old(void *data)
548 struct ivtv *itv = (struct ivtv *)data;
550 return read_reg(IVTV_REG_I2C_GETSCL_OFFSET) & 1;
553 static int ivtv_getsda_old(void *data)
555 struct ivtv *itv = (struct ivtv *)data;
557 return read_reg(IVTV_REG_I2C_GETSDA_OFFSET) & 1;
560 /* template for i2c-bit-algo */
561 static struct i2c_adapter ivtv_i2c_adap_template = {
562 .name = "ivtv i2c driver",
563 .id = I2C_HW_B_CX2341X,
564 .algo = NULL, /* set by i2c-algo-bit */
565 .algo_data = NULL, /* filled from template */
566 .owner = THIS_MODULE,
569 static const struct i2c_algo_bit_data ivtv_i2c_algo_template = {
570 .setsda = ivtv_setsda_old,
571 .setscl = ivtv_setscl_old,
572 .getsda = ivtv_getsda_old,
573 .getscl = ivtv_getscl_old,
578 static struct i2c_client ivtv_i2c_client_template = {
579 .name = "ivtv internal",
582 /* init + register i2c algo-bit adapter */
583 int init_ivtv_i2c(struct ivtv *itv)
585 IVTV_DEBUG_I2C("i2c init\n");
587 /* Sanity checks for the I2C hardware arrays. They must be the
588 * same size and GPIO must be the last entry.
590 if (ARRAY_SIZE(hw_devicenames) != ARRAY_SIZE(hw_addrs) ||
591 ARRAY_SIZE(hw_devicenames) != ARRAY_SIZE(hw_modules) ||
592 IVTV_HW_GPIO != (1 << (ARRAY_SIZE(hw_addrs) - 1))) {
593 IVTV_ERR("Mismatched I2C hardware arrays\n");
596 if (itv->options.newi2c > 0) {
597 memcpy(&itv->i2c_adap, &ivtv_i2c_adap_hw_template,
598 sizeof(struct i2c_adapter));
600 memcpy(&itv->i2c_adap, &ivtv_i2c_adap_template,
601 sizeof(struct i2c_adapter));
602 memcpy(&itv->i2c_algo, &ivtv_i2c_algo_template,
603 sizeof(struct i2c_algo_bit_data));
605 itv->i2c_algo.data = itv;
606 itv->i2c_adap.algo_data = &itv->i2c_algo;
608 sprintf(itv->i2c_adap.name + strlen(itv->i2c_adap.name), " #%d",
610 i2c_set_adapdata(&itv->i2c_adap, &itv->v4l2_dev);
612 memcpy(&itv->i2c_client, &ivtv_i2c_client_template,
613 sizeof(struct i2c_client));
614 itv->i2c_client.adapter = &itv->i2c_adap;
615 itv->i2c_adap.dev.parent = &itv->pdev->dev;
617 IVTV_DEBUG_I2C("setting scl and sda to 1\n");
621 if (itv->options.newi2c > 0)
622 return i2c_add_adapter(&itv->i2c_adap);
624 return i2c_bit_add_bus(&itv->i2c_adap);
627 void exit_ivtv_i2c(struct ivtv *itv)
629 IVTV_DEBUG_I2C("i2c exit\n");
631 i2c_del_adapter(&itv->i2c_adap);