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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
Jean Delvare5694f8a2012-03-26 21:47:19 +020018 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
19 MA 02110-1301 USA.
David Brownellcf978ab2008-01-27 18:14:46 +010020 * ------------------------------------------------------------------------- */
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
Jan Engelhardt96de0e22007-10-19 23:21:04 +020022/* With some changes from Frodo Looijaard <frodol@dds.nl>, Kyösti Mälkki
Jean Delvare7c81c602014-01-29 20:40:08 +010023 <kmalkki@cc.hut.fi> and Jean Delvare <jdelvare@suse.de> */
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
25#include <linux/kernel.h>
26#include <linux/module.h>
27#include <linux/delay.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#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 Delvare1bddab72011-10-30 13:47:25 +010050module_param(bit_test, int, S_IRUGO);
51MODULE_PARM_DESC(bit_test, "lines testing - 0 off; 1 report; 2 fail if stuck");
Jean Delvare494dbb62007-05-01 23:26:33 +020052
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 */
Ville Syrjala8ee161c2012-03-15 18:11:05 +0100106 if (time_after(jiffies, start + adap->timeout)) {
107 /* Test one last time, as we may have been preempted
108 * between last check and timeout test.
109 */
110 if (getscl(adap))
111 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 return -ETIMEDOUT;
Ville Syrjala8ee161c2012-03-15 18:11:05 +0100113 }
Jean Delvare41101a32012-03-26 21:47:19 +0200114 cpu_relax();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 }
Jean Delvare494dbb62007-05-01 23:26:33 +0200116#ifdef DEBUG
117 if (jiffies != start && i2c_debug >= 3)
118 pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go "
119 "high\n", jiffies - start);
120#endif
Jean Delvare7b288a02006-09-03 22:22:12 +0200121
122done:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 udelay(adap->udelay);
124 return 0;
David Brownellcf978ab2008-01-27 18:14:46 +0100125}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126
127
128/* --- other auxiliary functions -------------------------------------- */
David Brownellcf978ab2008-01-27 18:14:46 +0100129static void i2c_start(struct i2c_algo_bit_data *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130{
131 /* assert: scl, sda are high */
Jean Delvare424ed672007-05-01 23:26:33 +0200132 setsda(adap, 0);
133 udelay(adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 scllo(adap);
135}
136
David Brownellcf978ab2008-01-27 18:14:46 +0100137static void i2c_repstart(struct i2c_algo_bit_data *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138{
Jean Delvare424ed672007-05-01 23:26:33 +0200139 /* assert: scl is low */
Jean Delvare424ed672007-05-01 23:26:33 +0200140 sdahi(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 sclhi(adap);
Jean Delvare424ed672007-05-01 23:26:33 +0200142 setsda(adap, 0);
143 udelay(adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 scllo(adap);
145}
146
147
David Brownellcf978ab2008-01-27 18:14:46 +0100148static void i2c_stop(struct i2c_algo_bit_data *adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 /* assert: scl is low */
151 sdalo(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100152 sclhi(adap);
Jean Delvare424ed672007-05-01 23:26:33 +0200153 setsda(adap, 1);
154 udelay(adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155}
156
157
158
David Brownellcf978ab2008-01-27 18:14:46 +0100159/* send a byte without start cond., look for arbitration,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 check ackn. from slave */
161/* returns:
162 * 1 if the device acknowledged
163 * 0 if the device did not ack
164 * -ETIMEDOUT if an error occurred (while raising the scl line)
165 */
Jean Delvare494dbb62007-05-01 23:26:33 +0200166static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167{
168 int i;
169 int sb;
170 int ack;
171 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
172
173 /* assert: scl is low */
David Brownellcf978ab2008-01-27 18:14:46 +0100174 for (i = 7; i >= 0; i--) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200175 sb = (c >> i) & 1;
David Brownellcf978ab2008-01-27 18:14:46 +0100176 setsda(adap, sb);
Jean Delvare424ed672007-05-01 23:26:33 +0200177 udelay((adap->udelay + 1) / 2);
David Brownellcf978ab2008-01-27 18:14:46 +0100178 if (sclhi(adap) < 0) { /* timed out */
Jean Delvare494dbb62007-05-01 23:26:33 +0200179 bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
180 "timeout at bit #%d\n", (int)c, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 return -ETIMEDOUT;
David Brownellcf978ab2008-01-27 18:14:46 +0100182 }
183 /* FIXME do arbitration here:
184 * if (sb && !getsda(adap)) -> ouch! Get out of here.
185 *
186 * Report a unique code, so higher level code can retry
187 * the whole (combined) message and *NOT* issue STOP.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 */
Jean Delvare424ed672007-05-01 23:26:33 +0200189 scllo(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 }
191 sdahi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100192 if (sclhi(adap) < 0) { /* timeout */
Jean Delvare494dbb62007-05-01 23:26:33 +0200193 bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
194 "timeout at ack\n", (int)c);
195 return -ETIMEDOUT;
David Brownellcf978ab2008-01-27 18:14:46 +0100196 }
197
198 /* read ack: SDA should be pulled down by slave, or it may
199 * NAK (usually to report problems with the data we wrote).
200 */
Jean Delvare494dbb62007-05-01 23:26:33 +0200201 ack = !getsda(adap); /* ack: sda is pulled low -> success */
202 bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c,
203 ack ? "A" : "NA");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 scllo(adap);
Jean Delvare494dbb62007-05-01 23:26:33 +0200206 return ack;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 /* assert: scl is low (sda undef) */
208}
209
210
David Brownellcf978ab2008-01-27 18:14:46 +0100211static int i2c_inb(struct i2c_adapter *i2c_adap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212{
213 /* read byte via i2c port, without start/stop sequence */
214 /* acknowledge is sent in i2c_read. */
215 int i;
David Brownellcf978ab2008-01-27 18:14:46 +0100216 unsigned char indata = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
218
219 /* assert: scl is low */
220 sdahi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100221 for (i = 0; i < 8; i++) {
222 if (sclhi(adap) < 0) { /* timeout */
Jean Delvare494dbb62007-05-01 23:26:33 +0200223 bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit "
224 "#%d\n", 7 - i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 return -ETIMEDOUT;
David Brownellcf978ab2008-01-27 18:14:46 +0100226 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 indata *= 2;
David Brownellcf978ab2008-01-27 18:14:46 +0100228 if (getsda(adap))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 indata |= 0x01;
Jean Delvare424ed672007-05-01 23:26:33 +0200230 setscl(adap, 0);
231 udelay(i == 7 ? adap->udelay / 2 : adap->udelay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 }
233 /* assert: scl is low */
Jean Delvare494dbb62007-05-01 23:26:33 +0200234 return indata;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235}
236
237/*
238 * Sanity check for the adapter hardware - check the reaction of
239 * the bus lines only if it seems to be idle.
240 */
Alex Deucherd3b3e152011-04-17 10:20:19 +0200241static int test_bus(struct i2c_adapter *i2c_adap)
David Brownellcf978ab2008-01-27 18:14:46 +0100242{
Alex Deucherd3b3e152011-04-17 10:20:19 +0200243 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
244 const char *name = i2c_adap->name;
245 int scl, sda, ret;
246
247 if (adap->pre_xfer) {
248 ret = adap->pre_xfer(i2c_adap);
249 if (ret < 0)
250 return -ENODEV;
251 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
David Brownellcf978ab2008-01-27 18:14:46 +0100253 if (adap->getscl == NULL)
Jean Delvare494dbb62007-05-01 23:26:33 +0200254 pr_info("%s: Testing SDA only, SCL is not readable\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255
David Brownellcf978ab2008-01-27 18:14:46 +0100256 sda = getsda(adap);
257 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
258 if (!scl || !sda) {
Jean Delvaref6beb672011-10-30 13:47:25 +0100259 printk(KERN_WARNING
260 "%s: bus seems to be busy (scl=%d, sda=%d)\n",
261 name, scl, sda);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 goto bailout;
263 }
264
265 sdalo(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100266 sda = getsda(adap);
267 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
268 if (sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200269 printk(KERN_WARNING "%s: SDA stuck high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 goto bailout;
271 }
David Brownellcf978ab2008-01-27 18:14:46 +0100272 if (!scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200273 printk(KERN_WARNING "%s: SCL unexpected low "
274 "while pulling SDA low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 goto bailout;
David Brownellcf978ab2008-01-27 18:14:46 +0100276 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277
278 sdahi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100279 sda = getsda(adap);
280 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
281 if (!sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200282 printk(KERN_WARNING "%s: SDA stuck low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 goto bailout;
284 }
David Brownellcf978ab2008-01-27 18:14:46 +0100285 if (!scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200286 printk(KERN_WARNING "%s: SCL unexpected low "
287 "while pulling SDA high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 goto bailout;
289 }
290
291 scllo(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100292 sda = getsda(adap);
293 scl = (adap->getscl == NULL) ? 0 : getscl(adap);
294 if (scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200295 printk(KERN_WARNING "%s: SCL stuck high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 goto bailout;
297 }
David Brownellcf978ab2008-01-27 18:14:46 +0100298 if (!sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200299 printk(KERN_WARNING "%s: SDA unexpected low "
300 "while pulling SCL low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 goto bailout;
302 }
David Brownellcf978ab2008-01-27 18:14:46 +0100303
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 sclhi(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100305 sda = getsda(adap);
306 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
307 if (!scl) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200308 printk(KERN_WARNING "%s: SCL stuck low!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 goto bailout;
310 }
David Brownellcf978ab2008-01-27 18:14:46 +0100311 if (!sda) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200312 printk(KERN_WARNING "%s: SDA unexpected low "
313 "while pulling SCL high!\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 goto bailout;
315 }
Alex Deucherd3b3e152011-04-17 10:20:19 +0200316
317 if (adap->post_xfer)
318 adap->post_xfer(i2c_adap);
319
Jean Delvare494dbb62007-05-01 23:26:33 +0200320 pr_info("%s: Test OK\n", name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 return 0;
322bailout:
323 sdahi(adap);
324 sclhi(adap);
Alex Deucherd3b3e152011-04-17 10:20:19 +0200325
326 if (adap->post_xfer)
327 adap->post_xfer(i2c_adap);
328
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 return -ENODEV;
330}
331
332/* ----- Utility functions
333 */
334
335/* try_address tries to contact a chip for a number of
336 * times before it gives up.
337 * return values:
338 * 1 chip answered
339 * 0 chip did not answer
340 * -x transmission error
341 */
Jean Delvare7b288a02006-09-03 22:22:12 +0200342static int try_address(struct i2c_adapter *i2c_adap,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 unsigned char addr, int retries)
344{
345 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
David Brownell97140342008-07-14 22:38:25 +0200346 int i, ret = 0;
David Brownellcf978ab2008-01-27 18:14:46 +0100347
348 for (i = 0; i <= retries; i++) {
349 ret = i2c_outb(i2c_adap, addr);
Jean Delvare1ecac072007-05-01 23:26:28 +0200350 if (ret == 1 || i == retries)
351 break;
Jean Delvare494dbb62007-05-01 23:26:33 +0200352 bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 i2c_stop(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 udelay(adap->udelay);
Jean Delvare424ed672007-05-01 23:26:33 +0200355 yield();
Jean Delvare494dbb62007-05-01 23:26:33 +0200356 bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
Jean Delvare424ed672007-05-01 23:26:33 +0200357 i2c_start(adap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 }
Jean Delvare494dbb62007-05-01 23:26:33 +0200359 if (i && ret)
360 bit_dbg(1, &i2c_adap->dev, "Used %d tries to %s client at "
361 "0x%02x: %s\n", i + 1,
362 addr & 1 ? "read from" : "write to", addr >> 1,
363 ret == 1 ? "success" : "failed, timeout?");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 return ret;
365}
366
367static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
368{
Jean Delvare494dbb62007-05-01 23:26:33 +0200369 const unsigned char *temp = msg->buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 int count = msg->len;
David Brownellcf978ab2008-01-27 18:14:46 +0100371 unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 int retval;
David Brownellcf978ab2008-01-27 18:14:46 +0100373 int wrcount = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374
375 while (count > 0) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200376 retval = i2c_outb(i2c_adap, *temp);
David Brownellcf978ab2008-01-27 18:14:46 +0100377
378 /* OK/ACK; or ignored NAK */
379 if ((retval > 0) || (nak_ok && (retval == 0))) {
380 count--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 temp++;
382 wrcount++;
David Brownellbf3e2d12008-01-27 18:14:46 +0100383
384 /* A slave NAKing the master means the slave didn't like
385 * something about the data it saw. For example, maybe
386 * the SMBus PEC was wrong.
387 */
388 } else if (retval == 0) {
389 dev_err(&i2c_adap->dev, "sendbytes: NAK bailout.\n");
390 return -EIO;
391
392 /* Timeout; or (someday) lost arbitration
393 *
394 * FIXME Lost ARB implies retrying the transaction from
395 * the first message, after the "winning" master issues
396 * its STOP. As a rule, upper layer code has no reason
397 * to know or care about this ... it is *NOT* an error.
398 */
399 } else {
400 dev_err(&i2c_adap->dev, "sendbytes: error %d\n",
401 retval);
402 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 }
405 return wrcount;
406}
407
David Brownell939bc492007-09-09 22:29:14 +0200408static int acknak(struct i2c_adapter *i2c_adap, int is_ack)
409{
410 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
411
412 /* assert: sda is high */
413 if (is_ack) /* send ack */
414 setsda(adap, 0);
415 udelay((adap->udelay + 1) / 2);
416 if (sclhi(adap) < 0) { /* timeout */
417 dev_err(&i2c_adap->dev, "readbytes: ack/nak timeout\n");
418 return -ETIMEDOUT;
419 }
420 scllo(adap);
421 return 0;
422}
423
Jean Delvare7b288a02006-09-03 22:22:12 +0200424static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425{
426 int inval;
David Brownellcf978ab2008-01-27 18:14:46 +0100427 int rdcount = 0; /* counts bytes read */
Jean Delvare494dbb62007-05-01 23:26:33 +0200428 unsigned char *temp = msg->buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429 int count = msg->len;
David Brownell939bc492007-09-09 22:29:14 +0200430 const unsigned flags = msg->flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431
432 while (count > 0) {
433 inval = i2c_inb(i2c_adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100434 if (inval >= 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 *temp = inval;
436 rdcount++;
437 } else { /* read timed out */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 break;
439 }
440
441 temp++;
442 count--;
443
Jean Delvare3c4bb242007-05-01 23:26:29 +0200444 /* Some SMBus transactions require that we receive the
445 transaction length as the first read byte. */
David Brownell939bc492007-09-09 22:29:14 +0200446 if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) {
Jean Delvare3c4bb242007-05-01 23:26:29 +0200447 if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) {
David Brownell939bc492007-09-09 22:29:14 +0200448 if (!(flags & I2C_M_NO_RD_ACK))
449 acknak(i2c_adap, 0);
Jean Delvare494dbb62007-05-01 23:26:33 +0200450 dev_err(&i2c_adap->dev, "readbytes: invalid "
451 "block length (%d)\n", inval);
Jean Delvareabc01b22011-10-30 13:47:25 +0100452 return -EPROTO;
Jean Delvare3c4bb242007-05-01 23:26:29 +0200453 }
454 /* The original count value accounts for the extra
455 bytes, that is, either 1 for a regular transaction,
456 or 2 for a PEC transaction. */
457 count += inval;
458 msg->len += inval;
459 }
David Brownell939bc492007-09-09 22:29:14 +0200460
461 bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n",
462 inval,
463 (flags & I2C_M_NO_RD_ACK)
464 ? "(no ack/nak)"
465 : (count ? "A" : "NA"));
466
467 if (!(flags & I2C_M_NO_RD_ACK)) {
468 inval = acknak(i2c_adap, count);
469 if (inval < 0)
470 return inval;
471 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 }
473 return rdcount;
474}
475
476/* doAddress initiates the transfer by generating the start condition (in
477 * try_address) and transmits the address in the necessary format to handle
478 * reads, writes as well as 10bit-addresses.
479 * returns:
480 * 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set
Jean Delvareabc01b22011-10-30 13:47:25 +0100481 * -x an error occurred (like: -ENXIO if the device did not answer, or
David Brownellcf978ab2008-01-27 18:14:46 +0100482 * -ETIMEDOUT, for example if the lines are stuck...)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 */
Jean Delvare7b288a02006-09-03 22:22:12 +0200484static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485{
486 unsigned short flags = msg->flags;
487 unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
488 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
489
490 unsigned char addr;
491 int ret, retries;
492
493 retries = nak_ok ? 0 : i2c_adap->retries;
David Brownellcf978ab2008-01-27 18:14:46 +0100494
495 if (flags & I2C_M_TEN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 /* a ten bit address */
Jeffrey (Sheng-Hui) Chucc6bcf72011-11-23 11:33:07 +0100497 addr = 0xf0 | ((msg->addr >> 7) & 0x06);
Jean Delvare494dbb62007-05-01 23:26:33 +0200498 bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 /* try extended address code...*/
500 ret = try_address(i2c_adap, addr, retries);
501 if ((ret != 1) && !nak_ok) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200502 dev_err(&i2c_adap->dev,
503 "died at extended address code\n");
Jean Delvareabc01b22011-10-30 13:47:25 +0100504 return -ENXIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 }
506 /* the remaining 8 bit address */
Jeffrey (Sheng-Hui) Chucc6bcf72011-11-23 11:33:07 +0100507 ret = i2c_outb(i2c_adap, msg->addr & 0xff);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 if ((ret != 1) && !nak_ok) {
509 /* the chip did not ack / xmission error occurred */
Jean Delvare494dbb62007-05-01 23:26:33 +0200510 dev_err(&i2c_adap->dev, "died at 2nd address code\n");
Jean Delvareabc01b22011-10-30 13:47:25 +0100511 return -ENXIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 }
David Brownellcf978ab2008-01-27 18:14:46 +0100513 if (flags & I2C_M_RD) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200514 bit_dbg(3, &i2c_adap->dev, "emitting repeated "
515 "start condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 i2c_repstart(adap);
517 /* okay, now switch into reading mode */
518 addr |= 0x01;
519 ret = try_address(i2c_adap, addr, retries);
David Brownellcf978ab2008-01-27 18:14:46 +0100520 if ((ret != 1) && !nak_ok) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200521 dev_err(&i2c_adap->dev,
522 "died at repeated address code\n");
Jean Delvareabc01b22011-10-30 13:47:25 +0100523 return -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 }
525 }
526 } else { /* normal 7bit address */
David Brownellcf978ab2008-01-27 18:14:46 +0100527 addr = msg->addr << 1;
528 if (flags & I2C_M_RD)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 addr |= 1;
David Brownellcf978ab2008-01-27 18:14:46 +0100530 if (flags & I2C_M_REV_DIR_ADDR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 addr ^= 1;
532 ret = try_address(i2c_adap, addr, retries);
David Brownellcf978ab2008-01-27 18:14:46 +0100533 if ((ret != 1) && !nak_ok)
David Brownell97140342008-07-14 22:38:25 +0200534 return -ENXIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 }
536
537 return 0;
538}
539
540static int bit_xfer(struct i2c_adapter *i2c_adap,
541 struct i2c_msg msgs[], int num)
542{
543 struct i2c_msg *pmsg;
544 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
David Brownellcf978ab2008-01-27 18:14:46 +0100545 int i, ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 unsigned short nak_ok;
547
Jean Delvare0a9c1472010-03-13 20:56:56 +0100548 if (adap->pre_xfer) {
549 ret = adap->pre_xfer(i2c_adap);
550 if (ret < 0)
551 return ret;
552 }
553
Jean Delvare494dbb62007-05-01 23:26:33 +0200554 bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 i2c_start(adap);
David Brownellcf978ab2008-01-27 18:14:46 +0100556 for (i = 0; i < num; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 pmsg = &msgs[i];
David Brownellcf978ab2008-01-27 18:14:46 +0100558 nak_ok = pmsg->flags & I2C_M_IGNORE_NAK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 if (!(pmsg->flags & I2C_M_NOSTART)) {
560 if (i) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200561 bit_dbg(3, &i2c_adap->dev, "emitting "
562 "repeated start condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 i2c_repstart(adap);
564 }
565 ret = bit_doAddress(i2c_adap, pmsg);
566 if ((ret != 0) && !nak_ok) {
Jean Delvare494dbb62007-05-01 23:26:33 +0200567 bit_dbg(1, &i2c_adap->dev, "NAK from "
568 "device addr 0x%02x msg #%d\n",
569 msgs[i].addr, i);
Jean Delvare1ecac072007-05-01 23:26:28 +0200570 goto bailout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 }
572 }
David Brownellcf978ab2008-01-27 18:14:46 +0100573 if (pmsg->flags & I2C_M_RD) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 /* read bytes into buffer*/
575 ret = readbytes(i2c_adap, pmsg);
Jean Delvare494dbb62007-05-01 23:26:33 +0200576 if (ret >= 1)
577 bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n",
578 ret, ret == 1 ? "" : "s");
Jean Delvare1ecac072007-05-01 23:26:28 +0200579 if (ret < pmsg->len) {
580 if (ret >= 0)
Jean Delvareabc01b22011-10-30 13:47:25 +0100581 ret = -EIO;
Jean Delvare1ecac072007-05-01 23:26:28 +0200582 goto bailout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 }
584 } else {
585 /* write bytes from buffer */
586 ret = sendbytes(i2c_adap, pmsg);
Jean Delvare494dbb62007-05-01 23:26:33 +0200587 if (ret >= 1)
588 bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n",
589 ret, ret == 1 ? "" : "s");
Jean Delvare1ecac072007-05-01 23:26:28 +0200590 if (ret < pmsg->len) {
591 if (ret >= 0)
Jean Delvareabc01b22011-10-30 13:47:25 +0100592 ret = -EIO;
Jean Delvare1ecac072007-05-01 23:26:28 +0200593 goto bailout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 }
595 }
596 }
Jean Delvare1ecac072007-05-01 23:26:28 +0200597 ret = i;
598
599bailout:
Jean Delvare494dbb62007-05-01 23:26:33 +0200600 bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 i2c_stop(adap);
Jean Delvare0a9c1472010-03-13 20:56:56 +0100602
603 if (adap->post_xfer)
604 adap->post_xfer(i2c_adap);
Jean Delvare1ecac072007-05-01 23:26:28 +0200605 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606}
607
608static u32 bit_func(struct i2c_adapter *adap)
609{
Mark Brown14674e72012-05-30 10:55:34 +0200610 return I2C_FUNC_I2C | I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_EMUL |
Jean Delvare3c4bb242007-05-01 23:26:29 +0200611 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
612 I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
614}
615
616
617/* -----exported algorithm data: ------------------------------------- */
618
Daniel Vetterb0209b32012-02-28 00:39:39 +0100619const struct i2c_algorithm i2c_bit_algo = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 .master_xfer = bit_xfer,
621 .functionality = bit_func,
622};
Daniel Vetterb0209b32012-02-28 00:39:39 +0100623EXPORT_SYMBOL(i2c_bit_algo);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624
David Brownellcf978ab2008-01-27 18:14:46 +0100625/*
626 * registering functions to load algorithms at runtime
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 */
Jean Delvaref4511712011-01-10 22:11:23 +0100628static int __i2c_bit_add_bus(struct i2c_adapter *adap,
629 int (*add_adapter)(struct i2c_adapter *))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630{
631 struct i2c_algo_bit_data *bit_adap = adap->algo_data;
Jean Delvareaf5a60b2011-01-10 22:11:23 +0100632 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633
634 if (bit_test) {
Alex Deucherd3b3e152011-04-17 10:20:19 +0200635 ret = test_bus(adap);
Jean Delvare1bddab72011-10-30 13:47:25 +0100636 if (bit_test >= 2 && ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637 return -ENODEV;
638 }
639
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 /* register new adapter to i2c module... */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 adap->algo = &i2c_bit_algo;
Jean Delvare8fcfef62009-03-28 21:34:43 +0100642 adap->retries = 3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643
Jean Delvareaf5a60b2011-01-10 22:11:23 +0100644 ret = add_adapter(adap);
645 if (ret < 0)
646 return ret;
647
648 /* Complain if SCL can't be read */
649 if (bit_adap->getscl == NULL) {
650 dev_warn(&adap->dev, "Not I2C compliant: can't read SCL\n");
651 dev_warn(&adap->dev, "Bus may be unreliable\n");
652 }
653 return 0;
Jean Delvare0f3b4832007-05-01 23:26:31 +0200654}
655
656int i2c_bit_add_bus(struct i2c_adapter *adap)
657{
Jean Delvaref4511712011-01-10 22:11:23 +0100658 return __i2c_bit_add_bus(adap, i2c_add_adapter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660EXPORT_SYMBOL(i2c_bit_add_bus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661
Jean Delvare0f3b4832007-05-01 23:26:31 +0200662int i2c_bit_add_numbered_bus(struct i2c_adapter *adap)
663{
Jean Delvaref4511712011-01-10 22:11:23 +0100664 return __i2c_bit_add_bus(adap, i2c_add_numbered_adapter);
Jean Delvare0f3b4832007-05-01 23:26:31 +0200665}
666EXPORT_SYMBOL(i2c_bit_add_numbered_bus);
667
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
669MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm");
670MODULE_LICENSE("GPL");