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David Brownellcf978ab2008-01-27 18:14:46 +01001/* -------------------------------------------------------------------------
2 * i2c-algo-bit.c i2c driver algorithms for bit-shift adapters
3 * -------------------------------------------------------------------------
4 * Copyright (C) 1995-2000 Simon G. Vogl
Linus Torvalds1da177e2005-04-16 15:20:36 -07005
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.
10
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.
15
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
David Brownellcf978ab2008-01-27 18:14:46 +010018 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 * ------------------------------------------------------------------------- */
Linus Torvalds1da177e2005-04-16 15:20:36 -070020
Jan Engelhardt96de0e22007-10-19 23:21:04 +020021/* With some changes from Frodo Looijaard <frodol@dds.nl>, Kyösti Mälkki
Linus Torvalds1da177e2005-04-16 15:20:36 -070022 <kmalkki@cc.hut.fi> and Jean Delvare <khali@linux-fr.org> */
23
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/delay.h>
27#include <linux/slab.h>
28#include <linux/init.h>
29#include <linux/errno.h>
30#include <linux/sched.h>
31#include <linux/i2c.h>
32#include <linux/i2c-algo-bit.h>
33
34
35/* ----- global defines ----------------------------------------------- */
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
Jean Delvare494dbb62007-05-01 23:26:33 +020037#ifdef DEBUG
38#define bit_dbg(level, dev, format, args...) \
39 do { \
40 if (i2c_debug >= level) \
41 dev_dbg(dev, format, ##args); \
42 } while (0)
43#else
44#define bit_dbg(level, dev, format, args...) \
45 do {} while (0)
46#endif /* DEBUG */
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
48/* ----- global variables --------------------------------------------- */
49
Linus Torvalds1da177e2005-04-16 15:20:36 -070050static int bit_test; /* see if the line-setting functions work */
Jean Delvare494dbb62007-05-01 23:26:33 +020051module_param(bit_test, bool, 0);
52MODULE_PARM_DESC(bit_test, "Test the lines of the bus to see if it is stuck");
53
54#ifdef DEBUG
55static int i2c_debug = 1;
56module_param(i2c_debug, int, S_IRUGO | S_IWUSR);
57MODULE_PARM_DESC(i2c_debug,
58 "debug level - 0 off; 1 normal; 2 verbose; 3 very verbose");
59#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
61/* --- setting states on the bus with the right timing: --------------- */
62
David Brownellcf978ab2008-01-27 18:14:46 +010063#define setsda(adap, val) adap->setsda(adap->data, val)
64#define setscl(adap, val) adap->setscl(adap->data, val)
65#define getsda(adap) adap->getsda(adap->data)
66#define getscl(adap) adap->getscl(adap->data)
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
68static inline void sdalo(struct i2c_algo_bit_data *adap)
69{
David Brownellcf978ab2008-01-27 18:14:46 +010070 setsda(adap, 0);
Jean Delvare424ed672007-05-01 23:26:33 +020071 udelay((adap->udelay + 1) / 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -070072}
73
74static inline void sdahi(struct i2c_algo_bit_data *adap)
75{
David Brownellcf978ab2008-01-27 18:14:46 +010076 setsda(adap, 1);
Jean Delvare424ed672007-05-01 23:26:33 +020077 udelay((adap->udelay + 1) / 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078}
79
80static inline void scllo(struct i2c_algo_bit_data *adap)
81{
David Brownellcf978ab2008-01-27 18:14:46 +010082 setscl(adap, 0);
Jean Delvare424ed672007-05-01 23:26:33 +020083 udelay(adap->udelay / 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -070084}
85
86/*
87 * Raise scl line, and do checking for delays. This is necessary for slower
88 * devices.
89 */
Jean Delvare7b288a02006-09-03 22:22:12 +020090static int sclhi(struct i2c_algo_bit_data *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -070091{
92 unsigned long start;
93
David Brownellcf978ab2008-01-27 18:14:46 +010094 setscl(adap, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
96 /* Not all adapters have scl sense line... */
Jean Delvare7b288a02006-09-03 22:22:12 +020097 if (!adap->getscl)
98 goto done;
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
David Brownellcf978ab2008-01-27 18:14:46 +0100100 start = jiffies;
101 while (!getscl(adap)) {
102 /* This hw knows how to read the clock line, so we wait
103 * until it actually gets high. This is safer as some
104 * chips may hold it low ("clock stretching") while they
105 * are processing data internally.
106 */
107 if (time_after_eq(jiffies, start + adap->timeout))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 return -ETIMEDOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 cond_resched();
110 }
Jean Delvare494dbb62007-05-01 23:26:33 +0200111#ifdef DEBUG
112 if (jiffies != start && i2c_debug >= 3)
113 pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go "
114 "high\n", jiffies - start);
115#endif
Jean Delvare7b288a02006-09-03 22:22:12 +0200116
117done:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 udelay(adap->udelay);
119 return 0;
David Brownellcf978ab2008-01-27 18:14:46 +0100120}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121
122
123/* --- other auxiliary functions -------------------------------------- */
David Brownellcf978ab2008-01-27 18:14:46 +0100124static void i2c_start(struct i2c_algo_bit_data *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125{
126 /* assert: scl, sda are high */
Jean Delvare424ed672007-05-01 23:26:33 +0200127 setsda(adap, 0);
128 udelay(adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 scllo(adap);
130}
131
David Brownellcf978ab2008-01-27 18:14:46 +0100132static void i2c_repstart(struct i2c_algo_bit_data *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133{
Jean Delvare424ed672007-05-01 23:26:33 +0200134 /* assert: scl is low */
Jean Delvare424ed672007-05-01 23:26:33 +0200135 sdahi(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 sclhi(adap);
Jean Delvare424ed672007-05-01 23:26:33 +0200137 setsda(adap, 0);
138 udelay(adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 scllo(adap);
140}
141
142
David Brownellcf978ab2008-01-27 18:14:46 +0100143static void i2c_stop(struct i2c_algo_bit_data *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 /* assert: scl is low */
146 sdalo(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100147 sclhi(adap);
Jean Delvare424ed672007-05-01 23:26:33 +0200148 setsda(adap, 1);
149 udelay(adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150}
151
152
153
David Brownellcf978ab2008-01-27 18:14:46 +0100154/* send a byte without start cond., look for arbitration,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 check ackn. from slave */
156/* returns:
157 * 1 if the device acknowledged
158 * 0 if the device did not ack
159 * -ETIMEDOUT if an error occurred (while raising the scl line)
160 */
Jean Delvare494dbb62007-05-01 23:26:33 +0200161static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162{
163 int i;
164 int sb;
165 int ack;
166 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
167
168 /* assert: scl is low */
David Brownellcf978ab2008-01-27 18:14:46 +0100169 for (i = 7; i >= 0; i--) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200170 sb = (c >> i) & 1;
David Brownellcf978ab2008-01-27 18:14:46 +0100171 setsda(adap, sb);
Jean Delvare424ed672007-05-01 23:26:33 +0200172 udelay((adap->udelay + 1) / 2);
David Brownellcf978ab2008-01-27 18:14:46 +0100173 if (sclhi(adap) < 0) { /* timed out */
Jean Delvare494dbb62007-05-01 23:26:33 +0200174 bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
175 "timeout at bit #%d\n", (int)c, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 return -ETIMEDOUT;
David Brownellcf978ab2008-01-27 18:14:46 +0100177 }
178 /* FIXME do arbitration here:
179 * if (sb && !getsda(adap)) -> ouch! Get out of here.
180 *
181 * Report a unique code, so higher level code can retry
182 * the whole (combined) message and *NOT* issue STOP.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 */
Jean Delvare424ed672007-05-01 23:26:33 +0200184 scllo(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 }
186 sdahi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100187 if (sclhi(adap) < 0) { /* timeout */
Jean Delvare494dbb62007-05-01 23:26:33 +0200188 bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
189 "timeout at ack\n", (int)c);
190 return -ETIMEDOUT;
David Brownellcf978ab2008-01-27 18:14:46 +0100191 }
192
193 /* read ack: SDA should be pulled down by slave, or it may
194 * NAK (usually to report problems with the data we wrote).
195 */
Jean Delvare494dbb62007-05-01 23:26:33 +0200196 ack = !getsda(adap); /* ack: sda is pulled low -> success */
197 bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c,
198 ack ? "A" : "NA");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 scllo(adap);
Jean Delvare494dbb62007-05-01 23:26:33 +0200201 return ack;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 /* assert: scl is low (sda undef) */
203}
204
205
David Brownellcf978ab2008-01-27 18:14:46 +0100206static int i2c_inb(struct i2c_adapter *i2c_adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207{
208 /* read byte via i2c port, without start/stop sequence */
209 /* acknowledge is sent in i2c_read. */
210 int i;
David Brownellcf978ab2008-01-27 18:14:46 +0100211 unsigned char indata = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
213
214 /* assert: scl is low */
215 sdahi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100216 for (i = 0; i < 8; i++) {
217 if (sclhi(adap) < 0) { /* timeout */
Jean Delvare494dbb62007-05-01 23:26:33 +0200218 bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit "
219 "#%d\n", 7 - i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 return -ETIMEDOUT;
David Brownellcf978ab2008-01-27 18:14:46 +0100221 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 indata *= 2;
David Brownellcf978ab2008-01-27 18:14:46 +0100223 if (getsda(adap))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 indata |= 0x01;
Jean Delvare424ed672007-05-01 23:26:33 +0200225 setscl(adap, 0);
226 udelay(i == 7 ? adap->udelay / 2 : adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 }
228 /* assert: scl is low */
Jean Delvare494dbb62007-05-01 23:26:33 +0200229 return indata;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230}
231
232/*
233 * Sanity check for the adapter hardware - check the reaction of
234 * the bus lines only if it seems to be idle.
235 */
David Brownellcf978ab2008-01-27 18:14:46 +0100236static int test_bus(struct i2c_algo_bit_data *adap, char *name)
237{
238 int scl, sda;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239
David Brownellcf978ab2008-01-27 18:14:46 +0100240 if (adap->getscl == NULL)
Jean Delvare494dbb62007-05-01 23:26:33 +0200241 pr_info("%s: Testing SDA only, SCL is not readable\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242
David Brownellcf978ab2008-01-27 18:14:46 +0100243 sda = getsda(adap);
244 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
245 if (!scl || !sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200246 printk(KERN_WARNING "%s: bus seems to be busy\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 goto bailout;
248 }
249
250 sdalo(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100251 sda = getsda(adap);
252 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
253 if (sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200254 printk(KERN_WARNING "%s: SDA stuck high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 goto bailout;
256 }
David Brownellcf978ab2008-01-27 18:14:46 +0100257 if (!scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200258 printk(KERN_WARNING "%s: SCL unexpected low "
259 "while pulling SDA low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 goto bailout;
David Brownellcf978ab2008-01-27 18:14:46 +0100261 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262
263 sdahi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100264 sda = getsda(adap);
265 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
266 if (!sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200267 printk(KERN_WARNING "%s: SDA stuck low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 goto bailout;
269 }
David Brownellcf978ab2008-01-27 18:14:46 +0100270 if (!scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200271 printk(KERN_WARNING "%s: SCL unexpected low "
272 "while pulling SDA high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 goto bailout;
274 }
275
276 scllo(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100277 sda = getsda(adap);
278 scl = (adap->getscl == NULL) ? 0 : getscl(adap);
279 if (scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200280 printk(KERN_WARNING "%s: SCL stuck high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 goto bailout;
282 }
David Brownellcf978ab2008-01-27 18:14:46 +0100283 if (!sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200284 printk(KERN_WARNING "%s: SDA unexpected low "
285 "while pulling SCL low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 goto bailout;
287 }
David Brownellcf978ab2008-01-27 18:14:46 +0100288
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 sclhi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100290 sda = getsda(adap);
291 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
292 if (!scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200293 printk(KERN_WARNING "%s: SCL stuck low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 goto bailout;
295 }
David Brownellcf978ab2008-01-27 18:14:46 +0100296 if (!sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200297 printk(KERN_WARNING "%s: SDA unexpected low "
298 "while pulling SCL high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 goto bailout;
300 }
Jean Delvare494dbb62007-05-01 23:26:33 +0200301 pr_info("%s: Test OK\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 return 0;
303bailout:
304 sdahi(adap);
305 sclhi(adap);
306 return -ENODEV;
307}
308
309/* ----- Utility functions
310 */
311
312/* try_address tries to contact a chip for a number of
313 * times before it gives up.
314 * return values:
315 * 1 chip answered
316 * 0 chip did not answer
317 * -x transmission error
318 */
Jean Delvare7b288a02006-09-03 22:22:12 +0200319static int try_address(struct i2c_adapter *i2c_adap,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 unsigned char addr, int retries)
321{
322 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
David Brownellcf978ab2008-01-27 18:14:46 +0100323 int i, ret = -1;
324
325 for (i = 0; i <= retries; i++) {
326 ret = i2c_outb(i2c_adap, addr);
Jean Delvare1ecac072007-05-01 23:26:28 +0200327 if (ret == 1 || i == retries)
328 break;
Jean Delvare494dbb62007-05-01 23:26:33 +0200329 bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 i2c_stop(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 udelay(adap->udelay);
Jean Delvare424ed672007-05-01 23:26:33 +0200332 yield();
Jean Delvare494dbb62007-05-01 23:26:33 +0200333 bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
Jean Delvare424ed672007-05-01 23:26:33 +0200334 i2c_start(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 }
Jean Delvare494dbb62007-05-01 23:26:33 +0200336 if (i && ret)
337 bit_dbg(1, &i2c_adap->dev, "Used %d tries to %s client at "
338 "0x%02x: %s\n", i + 1,
339 addr & 1 ? "read from" : "write to", addr >> 1,
340 ret == 1 ? "success" : "failed, timeout?");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 return ret;
342}
343
344static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
345{
Jean Delvare494dbb62007-05-01 23:26:33 +0200346 const unsigned char *temp = msg->buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 int count = msg->len;
David Brownellcf978ab2008-01-27 18:14:46 +0100348 unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 int retval;
David Brownellcf978ab2008-01-27 18:14:46 +0100350 int wrcount = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351
352 while (count > 0) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200353 retval = i2c_outb(i2c_adap, *temp);
David Brownellcf978ab2008-01-27 18:14:46 +0100354
355 /* OK/ACK; or ignored NAK */
356 if ((retval > 0) || (nak_ok && (retval == 0))) {
357 count--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 temp++;
359 wrcount++;
David Brownellbf3e2d12008-01-27 18:14:46 +0100360
361 /* A slave NAKing the master means the slave didn't like
362 * something about the data it saw. For example, maybe
363 * the SMBus PEC was wrong.
364 */
365 } else if (retval == 0) {
366 dev_err(&i2c_adap->dev, "sendbytes: NAK bailout.\n");
367 return -EIO;
368
369 /* Timeout; or (someday) lost arbitration
370 *
371 * FIXME Lost ARB implies retrying the transaction from
372 * the first message, after the "winning" master issues
373 * its STOP. As a rule, upper layer code has no reason
374 * to know or care about this ... it is *NOT* an error.
375 */
376 } else {
377 dev_err(&i2c_adap->dev, "sendbytes: error %d\n",
378 retval);
379 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 }
382 return wrcount;
383}
384
David Brownell939bc492007-09-09 22:29:14 +0200385static int acknak(struct i2c_adapter *i2c_adap, int is_ack)
386{
387 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
388
389 /* assert: sda is high */
390 if (is_ack) /* send ack */
391 setsda(adap, 0);
392 udelay((adap->udelay + 1) / 2);
393 if (sclhi(adap) < 0) { /* timeout */
394 dev_err(&i2c_adap->dev, "readbytes: ack/nak timeout\n");
395 return -ETIMEDOUT;
396 }
397 scllo(adap);
398 return 0;
399}
400
Jean Delvare7b288a02006-09-03 22:22:12 +0200401static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402{
403 int inval;
David Brownellcf978ab2008-01-27 18:14:46 +0100404 int rdcount = 0; /* counts bytes read */
Jean Delvare494dbb62007-05-01 23:26:33 +0200405 unsigned char *temp = msg->buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 int count = msg->len;
David Brownell939bc492007-09-09 22:29:14 +0200407 const unsigned flags = msg->flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408
409 while (count > 0) {
410 inval = i2c_inb(i2c_adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100411 if (inval >= 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 *temp = inval;
413 rdcount++;
414 } else { /* read timed out */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 break;
416 }
417
418 temp++;
419 count--;
420
Jean Delvare3c4bb242007-05-01 23:26:29 +0200421 /* Some SMBus transactions require that we receive the
422 transaction length as the first read byte. */
David Brownell939bc492007-09-09 22:29:14 +0200423 if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) {
Jean Delvare3c4bb242007-05-01 23:26:29 +0200424 if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) {
David Brownell939bc492007-09-09 22:29:14 +0200425 if (!(flags & I2C_M_NO_RD_ACK))
426 acknak(i2c_adap, 0);
Jean Delvare494dbb62007-05-01 23:26:33 +0200427 dev_err(&i2c_adap->dev, "readbytes: invalid "
428 "block length (%d)\n", inval);
Jean Delvare3c4bb242007-05-01 23:26:29 +0200429 return -EREMOTEIO;
430 }
431 /* The original count value accounts for the extra
432 bytes, that is, either 1 for a regular transaction,
433 or 2 for a PEC transaction. */
434 count += inval;
435 msg->len += inval;
436 }
David Brownell939bc492007-09-09 22:29:14 +0200437
438 bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n",
439 inval,
440 (flags & I2C_M_NO_RD_ACK)
441 ? "(no ack/nak)"
442 : (count ? "A" : "NA"));
443
444 if (!(flags & I2C_M_NO_RD_ACK)) {
445 inval = acknak(i2c_adap, count);
446 if (inval < 0)
447 return inval;
448 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 }
450 return rdcount;
451}
452
453/* doAddress initiates the transfer by generating the start condition (in
454 * try_address) and transmits the address in the necessary format to handle
455 * reads, writes as well as 10bit-addresses.
456 * returns:
457 * 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set
458 * -x an error occurred (like: -EREMOTEIO if the device did not answer, or
David Brownellcf978ab2008-01-27 18:14:46 +0100459 * -ETIMEDOUT, for example if the lines are stuck...)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 */
Jean Delvare7b288a02006-09-03 22:22:12 +0200461static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462{
463 unsigned short flags = msg->flags;
464 unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
465 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
466
467 unsigned char addr;
468 int ret, retries;
469
470 retries = nak_ok ? 0 : i2c_adap->retries;
David Brownellcf978ab2008-01-27 18:14:46 +0100471
472 if (flags & I2C_M_TEN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 /* a ten bit address */
David Brownellcf978ab2008-01-27 18:14:46 +0100474 addr = 0xf0 | ((msg->addr >> 7) & 0x03);
Jean Delvare494dbb62007-05-01 23:26:33 +0200475 bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 /* try extended address code...*/
477 ret = try_address(i2c_adap, addr, retries);
478 if ((ret != 1) && !nak_ok) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200479 dev_err(&i2c_adap->dev,
480 "died at extended address code\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 return -EREMOTEIO;
482 }
483 /* the remaining 8 bit address */
David Brownellcf978ab2008-01-27 18:14:46 +0100484 ret = i2c_outb(i2c_adap, msg->addr & 0x7f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 if ((ret != 1) && !nak_ok) {
486 /* the chip did not ack / xmission error occurred */
Jean Delvare494dbb62007-05-01 23:26:33 +0200487 dev_err(&i2c_adap->dev, "died at 2nd address code\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 return -EREMOTEIO;
489 }
David Brownellcf978ab2008-01-27 18:14:46 +0100490 if (flags & I2C_M_RD) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200491 bit_dbg(3, &i2c_adap->dev, "emitting repeated "
492 "start condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 i2c_repstart(adap);
494 /* okay, now switch into reading mode */
495 addr |= 0x01;
496 ret = try_address(i2c_adap, addr, retries);
David Brownellcf978ab2008-01-27 18:14:46 +0100497 if ((ret != 1) && !nak_ok) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200498 dev_err(&i2c_adap->dev,
499 "died at repeated address code\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 return -EREMOTEIO;
501 }
502 }
503 } else { /* normal 7bit address */
David Brownellcf978ab2008-01-27 18:14:46 +0100504 addr = msg->addr << 1;
505 if (flags & I2C_M_RD)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 addr |= 1;
David Brownellcf978ab2008-01-27 18:14:46 +0100507 if (flags & I2C_M_REV_DIR_ADDR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 addr ^= 1;
509 ret = try_address(i2c_adap, addr, retries);
David Brownellcf978ab2008-01-27 18:14:46 +0100510 if ((ret != 1) && !nak_ok)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 return -EREMOTEIO;
512 }
513
514 return 0;
515}
516
517static int bit_xfer(struct i2c_adapter *i2c_adap,
518 struct i2c_msg msgs[], int num)
519{
520 struct i2c_msg *pmsg;
521 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
David Brownellcf978ab2008-01-27 18:14:46 +0100522 int i, ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 unsigned short nak_ok;
524
Jean Delvare494dbb62007-05-01 23:26:33 +0200525 bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 i2c_start(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100527 for (i = 0; i < num; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 pmsg = &msgs[i];
David Brownellcf978ab2008-01-27 18:14:46 +0100529 nak_ok = pmsg->flags & I2C_M_IGNORE_NAK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 if (!(pmsg->flags & I2C_M_NOSTART)) {
531 if (i) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200532 bit_dbg(3, &i2c_adap->dev, "emitting "
533 "repeated start condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 i2c_repstart(adap);
535 }
536 ret = bit_doAddress(i2c_adap, pmsg);
537 if ((ret != 0) && !nak_ok) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200538 bit_dbg(1, &i2c_adap->dev, "NAK from "
539 "device addr 0x%02x msg #%d\n",
540 msgs[i].addr, i);
Jean Delvare1ecac072007-05-01 23:26:28 +0200541 goto bailout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 }
543 }
David Brownellcf978ab2008-01-27 18:14:46 +0100544 if (pmsg->flags & I2C_M_RD) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 /* read bytes into buffer*/
546 ret = readbytes(i2c_adap, pmsg);
Jean Delvare494dbb62007-05-01 23:26:33 +0200547 if (ret >= 1)
548 bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n",
549 ret, ret == 1 ? "" : "s");
Jean Delvare1ecac072007-05-01 23:26:28 +0200550 if (ret < pmsg->len) {
551 if (ret >= 0)
552 ret = -EREMOTEIO;
553 goto bailout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 }
555 } else {
556 /* write bytes from buffer */
557 ret = sendbytes(i2c_adap, pmsg);
Jean Delvare494dbb62007-05-01 23:26:33 +0200558 if (ret >= 1)
559 bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n",
560 ret, ret == 1 ? "" : "s");
Jean Delvare1ecac072007-05-01 23:26:28 +0200561 if (ret < pmsg->len) {
562 if (ret >= 0)
563 ret = -EREMOTEIO;
564 goto bailout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 }
566 }
567 }
Jean Delvare1ecac072007-05-01 23:26:28 +0200568 ret = i;
569
570bailout:
Jean Delvare494dbb62007-05-01 23:26:33 +0200571 bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 i2c_stop(adap);
Jean Delvare1ecac072007-05-01 23:26:28 +0200573 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574}
575
576static u32 bit_func(struct i2c_adapter *adap)
577{
David Brownellcf978ab2008-01-27 18:14:46 +0100578 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
Jean Delvare3c4bb242007-05-01 23:26:29 +0200579 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
580 I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
582}
583
584
585/* -----exported algorithm data: ------------------------------------- */
586
Jean Delvare9e11a9f2006-09-03 22:38:52 +0200587static const struct i2c_algorithm i2c_bit_algo = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 .master_xfer = bit_xfer,
589 .functionality = bit_func,
590};
591
David Brownellcf978ab2008-01-27 18:14:46 +0100592/*
593 * registering functions to load algorithms at runtime
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 */
Jean Delvare0f3b4832007-05-01 23:26:31 +0200595static int i2c_bit_prepare_bus(struct i2c_adapter *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596{
597 struct i2c_algo_bit_data *bit_adap = adap->algo_data;
598
599 if (bit_test) {
600 int ret = test_bus(bit_adap, adap->name);
David Brownellcf978ab2008-01-27 18:14:46 +0100601 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 return -ENODEV;
603 }
604
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 /* register new adapter to i2c module... */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 adap->algo = &i2c_bit_algo;
607
608 adap->timeout = 100; /* default values, should */
609 adap->retries = 3; /* be replaced by defines */
610
Jean Delvare0f3b4832007-05-01 23:26:31 +0200611 return 0;
612}
613
614int i2c_bit_add_bus(struct i2c_adapter *adap)
615{
616 int err;
617
618 err = i2c_bit_prepare_bus(adap);
619 if (err)
620 return err;
621
Mark M. Hoffmanb39ad0c2006-07-01 17:16:06 +0200622 return i2c_add_adapter(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624EXPORT_SYMBOL(i2c_bit_add_bus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625
Jean Delvare0f3b4832007-05-01 23:26:31 +0200626int i2c_bit_add_numbered_bus(struct i2c_adapter *adap)
627{
628 int err;
629
630 err = i2c_bit_prepare_bus(adap);
631 if (err)
632 return err;
633
634 return i2c_add_numbered_adapter(adap);
635}
636EXPORT_SYMBOL(i2c_bit_add_numbered_bus);
637
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
639MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm");
640MODULE_LICENSE("GPL");