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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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/init.h>
28#include <linux/errno.h>
29#include <linux/sched.h>
30#include <linux/i2c.h>
31#include <linux/i2c-algo-bit.h>
32
33
34/* ----- global defines ----------------------------------------------- */
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
Jean Delvare494dbb62007-05-01 23:26:33 +020036#ifdef DEBUG
37#define bit_dbg(level, dev, format, args...) \
38 do { \
39 if (i2c_debug >= level) \
40 dev_dbg(dev, format, ##args); \
41 } while (0)
42#else
43#define bit_dbg(level, dev, format, args...) \
44 do {} while (0)
45#endif /* DEBUG */
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
47/* ----- global variables --------------------------------------------- */
48
Linus Torvalds1da177e2005-04-16 15:20:36 -070049static int bit_test; /* see if the line-setting functions work */
Jean Delvare494dbb62007-05-01 23:26:33 +020050module_param(bit_test, bool, 0);
51MODULE_PARM_DESC(bit_test, "Test the lines of the bus to see if it is stuck");
52
53#ifdef DEBUG
54static int i2c_debug = 1;
55module_param(i2c_debug, int, S_IRUGO | S_IWUSR);
56MODULE_PARM_DESC(i2c_debug,
57 "debug level - 0 off; 1 normal; 2 verbose; 3 very verbose");
58#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
60/* --- setting states on the bus with the right timing: --------------- */
61
David Brownellcf978ab2008-01-27 18:14:46 +010062#define setsda(adap, val) adap->setsda(adap->data, val)
63#define setscl(adap, val) adap->setscl(adap->data, val)
64#define getsda(adap) adap->getsda(adap->data)
65#define getscl(adap) adap->getscl(adap->data)
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
67static inline void sdalo(struct i2c_algo_bit_data *adap)
68{
David Brownellcf978ab2008-01-27 18:14:46 +010069 setsda(adap, 0);
Jean Delvare424ed672007-05-01 23:26:33 +020070 udelay((adap->udelay + 1) / 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071}
72
73static inline void sdahi(struct i2c_algo_bit_data *adap)
74{
David Brownellcf978ab2008-01-27 18:14:46 +010075 setsda(adap, 1);
Jean Delvare424ed672007-05-01 23:26:33 +020076 udelay((adap->udelay + 1) / 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077}
78
79static inline void scllo(struct i2c_algo_bit_data *adap)
80{
David Brownellcf978ab2008-01-27 18:14:46 +010081 setscl(adap, 0);
Jean Delvare424ed672007-05-01 23:26:33 +020082 udelay(adap->udelay / 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083}
84
85/*
86 * Raise scl line, and do checking for delays. This is necessary for slower
87 * devices.
88 */
Jean Delvare7b288a02006-09-03 22:22:12 +020089static int sclhi(struct i2c_algo_bit_data *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -070090{
91 unsigned long start;
92
David Brownellcf978ab2008-01-27 18:14:46 +010093 setscl(adap, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
95 /* Not all adapters have scl sense line... */
Jean Delvare7b288a02006-09-03 22:22:12 +020096 if (!adap->getscl)
97 goto done;
Linus Torvalds1da177e2005-04-16 15:20:36 -070098
David Brownellcf978ab2008-01-27 18:14:46 +010099 start = jiffies;
100 while (!getscl(adap)) {
101 /* This hw knows how to read the clock line, so we wait
102 * until it actually gets high. This is safer as some
103 * chips may hold it low ("clock stretching") while they
104 * are processing data internally.
105 */
Dave Airlie0cdba072009-05-05 08:39:24 +0200106 if (time_after(jiffies, start + adap->timeout))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 return -ETIMEDOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 cond_resched();
109 }
Jean Delvare494dbb62007-05-01 23:26:33 +0200110#ifdef DEBUG
111 if (jiffies != start && i2c_debug >= 3)
112 pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go "
113 "high\n", jiffies - start);
114#endif
Jean Delvare7b288a02006-09-03 22:22:12 +0200115
116done:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 udelay(adap->udelay);
118 return 0;
David Brownellcf978ab2008-01-27 18:14:46 +0100119}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
121
122/* --- other auxiliary functions -------------------------------------- */
David Brownellcf978ab2008-01-27 18:14:46 +0100123static void i2c_start(struct i2c_algo_bit_data *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124{
125 /* assert: scl, sda are high */
Jean Delvare424ed672007-05-01 23:26:33 +0200126 setsda(adap, 0);
127 udelay(adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 scllo(adap);
129}
130
David Brownellcf978ab2008-01-27 18:14:46 +0100131static void i2c_repstart(struct i2c_algo_bit_data *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132{
Jean Delvare424ed672007-05-01 23:26:33 +0200133 /* assert: scl is low */
Jean Delvare424ed672007-05-01 23:26:33 +0200134 sdahi(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 sclhi(adap);
Jean Delvare424ed672007-05-01 23:26:33 +0200136 setsda(adap, 0);
137 udelay(adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 scllo(adap);
139}
140
141
David Brownellcf978ab2008-01-27 18:14:46 +0100142static void i2c_stop(struct i2c_algo_bit_data *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 /* assert: scl is low */
145 sdalo(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100146 sclhi(adap);
Jean Delvare424ed672007-05-01 23:26:33 +0200147 setsda(adap, 1);
148 udelay(adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149}
150
151
152
David Brownellcf978ab2008-01-27 18:14:46 +0100153/* send a byte without start cond., look for arbitration,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 check ackn. from slave */
155/* returns:
156 * 1 if the device acknowledged
157 * 0 if the device did not ack
158 * -ETIMEDOUT if an error occurred (while raising the scl line)
159 */
Jean Delvare494dbb62007-05-01 23:26:33 +0200160static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161{
162 int i;
163 int sb;
164 int ack;
165 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
166
167 /* assert: scl is low */
David Brownellcf978ab2008-01-27 18:14:46 +0100168 for (i = 7; i >= 0; i--) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200169 sb = (c >> i) & 1;
David Brownellcf978ab2008-01-27 18:14:46 +0100170 setsda(adap, sb);
Jean Delvare424ed672007-05-01 23:26:33 +0200171 udelay((adap->udelay + 1) / 2);
David Brownellcf978ab2008-01-27 18:14:46 +0100172 if (sclhi(adap) < 0) { /* timed out */
Jean Delvare494dbb62007-05-01 23:26:33 +0200173 bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
174 "timeout at bit #%d\n", (int)c, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 return -ETIMEDOUT;
David Brownellcf978ab2008-01-27 18:14:46 +0100176 }
177 /* FIXME do arbitration here:
178 * if (sb && !getsda(adap)) -> ouch! Get out of here.
179 *
180 * Report a unique code, so higher level code can retry
181 * the whole (combined) message and *NOT* issue STOP.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 */
Jean Delvare424ed672007-05-01 23:26:33 +0200183 scllo(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 }
185 sdahi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100186 if (sclhi(adap) < 0) { /* timeout */
Jean Delvare494dbb62007-05-01 23:26:33 +0200187 bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
188 "timeout at ack\n", (int)c);
189 return -ETIMEDOUT;
David Brownellcf978ab2008-01-27 18:14:46 +0100190 }
191
192 /* read ack: SDA should be pulled down by slave, or it may
193 * NAK (usually to report problems with the data we wrote).
194 */
Jean Delvare494dbb62007-05-01 23:26:33 +0200195 ack = !getsda(adap); /* ack: sda is pulled low -> success */
196 bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c,
197 ack ? "A" : "NA");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 scllo(adap);
Jean Delvare494dbb62007-05-01 23:26:33 +0200200 return ack;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 /* assert: scl is low (sda undef) */
202}
203
204
David Brownellcf978ab2008-01-27 18:14:46 +0100205static int i2c_inb(struct i2c_adapter *i2c_adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206{
207 /* read byte via i2c port, without start/stop sequence */
208 /* acknowledge is sent in i2c_read. */
209 int i;
David Brownellcf978ab2008-01-27 18:14:46 +0100210 unsigned char indata = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
212
213 /* assert: scl is low */
214 sdahi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100215 for (i = 0; i < 8; i++) {
216 if (sclhi(adap) < 0) { /* timeout */
Jean Delvare494dbb62007-05-01 23:26:33 +0200217 bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit "
218 "#%d\n", 7 - i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 return -ETIMEDOUT;
David Brownellcf978ab2008-01-27 18:14:46 +0100220 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 indata *= 2;
David Brownellcf978ab2008-01-27 18:14:46 +0100222 if (getsda(adap))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 indata |= 0x01;
Jean Delvare424ed672007-05-01 23:26:33 +0200224 setscl(adap, 0);
225 udelay(i == 7 ? adap->udelay / 2 : adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 }
227 /* assert: scl is low */
Jean Delvare494dbb62007-05-01 23:26:33 +0200228 return indata;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229}
230
231/*
232 * Sanity check for the adapter hardware - check the reaction of
233 * the bus lines only if it seems to be idle.
234 */
David Brownellcf978ab2008-01-27 18:14:46 +0100235static int test_bus(struct i2c_algo_bit_data *adap, char *name)
236{
237 int scl, sda;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238
David Brownellcf978ab2008-01-27 18:14:46 +0100239 if (adap->getscl == NULL)
Jean Delvare494dbb62007-05-01 23:26:33 +0200240 pr_info("%s: Testing SDA only, SCL is not readable\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241
David Brownellcf978ab2008-01-27 18:14:46 +0100242 sda = getsda(adap);
243 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
244 if (!scl || !sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200245 printk(KERN_WARNING "%s: bus seems to be busy\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 goto bailout;
247 }
248
249 sdalo(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100250 sda = getsda(adap);
251 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
252 if (sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200253 printk(KERN_WARNING "%s: SDA stuck high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 goto bailout;
255 }
David Brownellcf978ab2008-01-27 18:14:46 +0100256 if (!scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200257 printk(KERN_WARNING "%s: SCL unexpected low "
258 "while pulling SDA low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 goto bailout;
David Brownellcf978ab2008-01-27 18:14:46 +0100260 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
262 sdahi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100263 sda = getsda(adap);
264 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
265 if (!sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200266 printk(KERN_WARNING "%s: SDA stuck low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 goto bailout;
268 }
David Brownellcf978ab2008-01-27 18:14:46 +0100269 if (!scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200270 printk(KERN_WARNING "%s: SCL unexpected low "
271 "while pulling SDA high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 goto bailout;
273 }
274
275 scllo(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100276 sda = getsda(adap);
277 scl = (adap->getscl == NULL) ? 0 : getscl(adap);
278 if (scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200279 printk(KERN_WARNING "%s: SCL stuck high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 goto bailout;
281 }
David Brownellcf978ab2008-01-27 18:14:46 +0100282 if (!sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200283 printk(KERN_WARNING "%s: SDA unexpected low "
284 "while pulling SCL low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 goto bailout;
286 }
David Brownellcf978ab2008-01-27 18:14:46 +0100287
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 sclhi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100289 sda = getsda(adap);
290 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
291 if (!scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200292 printk(KERN_WARNING "%s: SCL stuck low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 goto bailout;
294 }
David Brownellcf978ab2008-01-27 18:14:46 +0100295 if (!sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200296 printk(KERN_WARNING "%s: SDA unexpected low "
297 "while pulling SCL high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 goto bailout;
299 }
Jean Delvare494dbb62007-05-01 23:26:33 +0200300 pr_info("%s: Test OK\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 return 0;
302bailout:
303 sdahi(adap);
304 sclhi(adap);
305 return -ENODEV;
306}
307
308/* ----- Utility functions
309 */
310
311/* try_address tries to contact a chip for a number of
312 * times before it gives up.
313 * return values:
314 * 1 chip answered
315 * 0 chip did not answer
316 * -x transmission error
317 */
Jean Delvare7b288a02006-09-03 22:22:12 +0200318static int try_address(struct i2c_adapter *i2c_adap,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 unsigned char addr, int retries)
320{
321 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
David Brownell97140342008-07-14 22:38:25 +0200322 int i, ret = 0;
David Brownellcf978ab2008-01-27 18:14:46 +0100323
324 for (i = 0; i <= retries; i++) {
325 ret = i2c_outb(i2c_adap, addr);
Jean Delvare1ecac072007-05-01 23:26:28 +0200326 if (ret == 1 || i == retries)
327 break;
Jean Delvare494dbb62007-05-01 23:26:33 +0200328 bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 i2c_stop(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 udelay(adap->udelay);
Jean Delvare424ed672007-05-01 23:26:33 +0200331 yield();
Jean Delvare494dbb62007-05-01 23:26:33 +0200332 bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
Jean Delvare424ed672007-05-01 23:26:33 +0200333 i2c_start(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 }
Jean Delvare494dbb62007-05-01 23:26:33 +0200335 if (i && ret)
336 bit_dbg(1, &i2c_adap->dev, "Used %d tries to %s client at "
337 "0x%02x: %s\n", i + 1,
338 addr & 1 ? "read from" : "write to", addr >> 1,
339 ret == 1 ? "success" : "failed, timeout?");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 return ret;
341}
342
343static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
344{
Jean Delvare494dbb62007-05-01 23:26:33 +0200345 const unsigned char *temp = msg->buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 int count = msg->len;
David Brownellcf978ab2008-01-27 18:14:46 +0100347 unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 int retval;
David Brownellcf978ab2008-01-27 18:14:46 +0100349 int wrcount = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350
351 while (count > 0) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200352 retval = i2c_outb(i2c_adap, *temp);
David Brownellcf978ab2008-01-27 18:14:46 +0100353
354 /* OK/ACK; or ignored NAK */
355 if ((retval > 0) || (nak_ok && (retval == 0))) {
356 count--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 temp++;
358 wrcount++;
David Brownellbf3e2d12008-01-27 18:14:46 +0100359
360 /* A slave NAKing the master means the slave didn't like
361 * something about the data it saw. For example, maybe
362 * the SMBus PEC was wrong.
363 */
364 } else if (retval == 0) {
365 dev_err(&i2c_adap->dev, "sendbytes: NAK bailout.\n");
366 return -EIO;
367
368 /* Timeout; or (someday) lost arbitration
369 *
370 * FIXME Lost ARB implies retrying the transaction from
371 * the first message, after the "winning" master issues
372 * its STOP. As a rule, upper layer code has no reason
373 * to know or care about this ... it is *NOT* an error.
374 */
375 } else {
376 dev_err(&i2c_adap->dev, "sendbytes: error %d\n",
377 retval);
378 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 }
381 return wrcount;
382}
383
David Brownell939bc492007-09-09 22:29:14 +0200384static int acknak(struct i2c_adapter *i2c_adap, int is_ack)
385{
386 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
387
388 /* assert: sda is high */
389 if (is_ack) /* send ack */
390 setsda(adap, 0);
391 udelay((adap->udelay + 1) / 2);
392 if (sclhi(adap) < 0) { /* timeout */
393 dev_err(&i2c_adap->dev, "readbytes: ack/nak timeout\n");
394 return -ETIMEDOUT;
395 }
396 scllo(adap);
397 return 0;
398}
399
Jean Delvare7b288a02006-09-03 22:22:12 +0200400static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401{
402 int inval;
David Brownellcf978ab2008-01-27 18:14:46 +0100403 int rdcount = 0; /* counts bytes read */
Jean Delvare494dbb62007-05-01 23:26:33 +0200404 unsigned char *temp = msg->buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 int count = msg->len;
David Brownell939bc492007-09-09 22:29:14 +0200406 const unsigned flags = msg->flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407
408 while (count > 0) {
409 inval = i2c_inb(i2c_adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100410 if (inval >= 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 *temp = inval;
412 rdcount++;
413 } else { /* read timed out */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 break;
415 }
416
417 temp++;
418 count--;
419
Jean Delvare3c4bb242007-05-01 23:26:29 +0200420 /* Some SMBus transactions require that we receive the
421 transaction length as the first read byte. */
David Brownell939bc492007-09-09 22:29:14 +0200422 if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) {
Jean Delvare3c4bb242007-05-01 23:26:29 +0200423 if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) {
David Brownell939bc492007-09-09 22:29:14 +0200424 if (!(flags & I2C_M_NO_RD_ACK))
425 acknak(i2c_adap, 0);
Jean Delvare494dbb62007-05-01 23:26:33 +0200426 dev_err(&i2c_adap->dev, "readbytes: invalid "
427 "block length (%d)\n", inval);
Jean Delvare3c4bb242007-05-01 23:26:29 +0200428 return -EREMOTEIO;
429 }
430 /* The original count value accounts for the extra
431 bytes, that is, either 1 for a regular transaction,
432 or 2 for a PEC transaction. */
433 count += inval;
434 msg->len += inval;
435 }
David Brownell939bc492007-09-09 22:29:14 +0200436
437 bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n",
438 inval,
439 (flags & I2C_M_NO_RD_ACK)
440 ? "(no ack/nak)"
441 : (count ? "A" : "NA"));
442
443 if (!(flags & I2C_M_NO_RD_ACK)) {
444 inval = acknak(i2c_adap, count);
445 if (inval < 0)
446 return inval;
447 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 }
449 return rdcount;
450}
451
452/* doAddress initiates the transfer by generating the start condition (in
453 * try_address) and transmits the address in the necessary format to handle
454 * reads, writes as well as 10bit-addresses.
455 * returns:
456 * 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set
457 * -x an error occurred (like: -EREMOTEIO if the device did not answer, or
David Brownellcf978ab2008-01-27 18:14:46 +0100458 * -ETIMEDOUT, for example if the lines are stuck...)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 */
Jean Delvare7b288a02006-09-03 22:22:12 +0200460static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461{
462 unsigned short flags = msg->flags;
463 unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
464 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
465
466 unsigned char addr;
467 int ret, retries;
468
469 retries = nak_ok ? 0 : i2c_adap->retries;
David Brownellcf978ab2008-01-27 18:14:46 +0100470
471 if (flags & I2C_M_TEN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 /* a ten bit address */
David Brownellcf978ab2008-01-27 18:14:46 +0100473 addr = 0xf0 | ((msg->addr >> 7) & 0x03);
Jean Delvare494dbb62007-05-01 23:26:33 +0200474 bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 /* try extended address code...*/
476 ret = try_address(i2c_adap, addr, retries);
477 if ((ret != 1) && !nak_ok) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200478 dev_err(&i2c_adap->dev,
479 "died at extended address code\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 return -EREMOTEIO;
481 }
482 /* the remaining 8 bit address */
David Brownellcf978ab2008-01-27 18:14:46 +0100483 ret = i2c_outb(i2c_adap, msg->addr & 0x7f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 if ((ret != 1) && !nak_ok) {
485 /* the chip did not ack / xmission error occurred */
Jean Delvare494dbb62007-05-01 23:26:33 +0200486 dev_err(&i2c_adap->dev, "died at 2nd address code\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 return -EREMOTEIO;
488 }
David Brownellcf978ab2008-01-27 18:14:46 +0100489 if (flags & I2C_M_RD) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200490 bit_dbg(3, &i2c_adap->dev, "emitting repeated "
491 "start condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 i2c_repstart(adap);
493 /* okay, now switch into reading mode */
494 addr |= 0x01;
495 ret = try_address(i2c_adap, addr, retries);
David Brownellcf978ab2008-01-27 18:14:46 +0100496 if ((ret != 1) && !nak_ok) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200497 dev_err(&i2c_adap->dev,
498 "died at repeated address code\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 return -EREMOTEIO;
500 }
501 }
502 } else { /* normal 7bit address */
David Brownellcf978ab2008-01-27 18:14:46 +0100503 addr = msg->addr << 1;
504 if (flags & I2C_M_RD)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 addr |= 1;
David Brownellcf978ab2008-01-27 18:14:46 +0100506 if (flags & I2C_M_REV_DIR_ADDR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 addr ^= 1;
508 ret = try_address(i2c_adap, addr, retries);
David Brownellcf978ab2008-01-27 18:14:46 +0100509 if ((ret != 1) && !nak_ok)
David Brownell97140342008-07-14 22:38:25 +0200510 return -ENXIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 }
512
513 return 0;
514}
515
516static int bit_xfer(struct i2c_adapter *i2c_adap,
517 struct i2c_msg msgs[], int num)
518{
519 struct i2c_msg *pmsg;
520 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
David Brownellcf978ab2008-01-27 18:14:46 +0100521 int i, ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 unsigned short nak_ok;
523
Jean Delvare0a9c1472010-03-13 20:56:56 +0100524 if (adap->pre_xfer) {
525 ret = adap->pre_xfer(i2c_adap);
526 if (ret < 0)
527 return ret;
528 }
529
Jean Delvare494dbb62007-05-01 23:26:33 +0200530 bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 i2c_start(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100532 for (i = 0; i < num; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 pmsg = &msgs[i];
David Brownellcf978ab2008-01-27 18:14:46 +0100534 nak_ok = pmsg->flags & I2C_M_IGNORE_NAK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 if (!(pmsg->flags & I2C_M_NOSTART)) {
536 if (i) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200537 bit_dbg(3, &i2c_adap->dev, "emitting "
538 "repeated start condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 i2c_repstart(adap);
540 }
541 ret = bit_doAddress(i2c_adap, pmsg);
542 if ((ret != 0) && !nak_ok) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200543 bit_dbg(1, &i2c_adap->dev, "NAK from "
544 "device addr 0x%02x msg #%d\n",
545 msgs[i].addr, i);
Jean Delvare1ecac072007-05-01 23:26:28 +0200546 goto bailout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 }
548 }
David Brownellcf978ab2008-01-27 18:14:46 +0100549 if (pmsg->flags & I2C_M_RD) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 /* read bytes into buffer*/
551 ret = readbytes(i2c_adap, pmsg);
Jean Delvare494dbb62007-05-01 23:26:33 +0200552 if (ret >= 1)
553 bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n",
554 ret, ret == 1 ? "" : "s");
Jean Delvare1ecac072007-05-01 23:26:28 +0200555 if (ret < pmsg->len) {
556 if (ret >= 0)
557 ret = -EREMOTEIO;
558 goto bailout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 }
560 } else {
561 /* write bytes from buffer */
562 ret = sendbytes(i2c_adap, pmsg);
Jean Delvare494dbb62007-05-01 23:26:33 +0200563 if (ret >= 1)
564 bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n",
565 ret, ret == 1 ? "" : "s");
Jean Delvare1ecac072007-05-01 23:26:28 +0200566 if (ret < pmsg->len) {
567 if (ret >= 0)
568 ret = -EREMOTEIO;
569 goto bailout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 }
571 }
572 }
Jean Delvare1ecac072007-05-01 23:26:28 +0200573 ret = i;
574
575bailout:
Jean Delvare494dbb62007-05-01 23:26:33 +0200576 bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 i2c_stop(adap);
Jean Delvare0a9c1472010-03-13 20:56:56 +0100578
579 if (adap->post_xfer)
580 adap->post_xfer(i2c_adap);
Jean Delvare1ecac072007-05-01 23:26:28 +0200581 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582}
583
584static u32 bit_func(struct i2c_adapter *adap)
585{
David Brownellcf978ab2008-01-27 18:14:46 +0100586 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
Jean Delvare3c4bb242007-05-01 23:26:29 +0200587 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
588 I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
590}
591
592
593/* -----exported algorithm data: ------------------------------------- */
594
Jean Delvare9e11a9f2006-09-03 22:38:52 +0200595static const struct i2c_algorithm i2c_bit_algo = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 .master_xfer = bit_xfer,
597 .functionality = bit_func,
598};
599
David Brownellcf978ab2008-01-27 18:14:46 +0100600/*
601 * registering functions to load algorithms at runtime
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 */
Jean Delvare0f3b4832007-05-01 23:26:31 +0200603static int i2c_bit_prepare_bus(struct i2c_adapter *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604{
605 struct i2c_algo_bit_data *bit_adap = adap->algo_data;
606
607 if (bit_test) {
608 int ret = test_bus(bit_adap, adap->name);
David Brownellcf978ab2008-01-27 18:14:46 +0100609 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 return -ENODEV;
611 }
612
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 /* register new adapter to i2c module... */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 adap->algo = &i2c_bit_algo;
Jean Delvare8fcfef62009-03-28 21:34:43 +0100615 adap->retries = 3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616
Jean Delvare0f3b4832007-05-01 23:26:31 +0200617 return 0;
618}
619
620int i2c_bit_add_bus(struct i2c_adapter *adap)
621{
622 int err;
623
624 err = i2c_bit_prepare_bus(adap);
625 if (err)
626 return err;
627
Mark M. Hoffmanb39ad0c2006-07-01 17:16:06 +0200628 return i2c_add_adapter(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630EXPORT_SYMBOL(i2c_bit_add_bus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631
Jean Delvare0f3b4832007-05-01 23:26:31 +0200632int i2c_bit_add_numbered_bus(struct i2c_adapter *adap)
633{
634 int err;
635
636 err = i2c_bit_prepare_bus(adap);
637 if (err)
638 return err;
639
640 return i2c_add_numbered_adapter(adap);
641}
642EXPORT_SYMBOL(i2c_bit_add_numbered_bus);
643
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
645MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm");
646MODULE_LICENSE("GPL");