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-rw-r--r--drivers/net/sfc/i2c-direct.c381
1 files changed, 0 insertions, 381 deletions
diff --git a/drivers/net/sfc/i2c-direct.c b/drivers/net/sfc/i2c-direct.c
deleted file mode 100644
index b6c62d0ed9c2..000000000000
--- a/drivers/net/sfc/i2c-direct.c
+++ /dev/null
@@ -1,381 +0,0 @@
1/****************************************************************************
2 * Driver for Solarflare Solarstorm network controllers and boards
3 * Copyright 2005 Fen Systems Ltd.
4 * Copyright 2006-2008 Solarflare Communications Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation, incorporated herein by reference.
9 */
10
11#include <linux/delay.h>
12#include "net_driver.h"
13#include "i2c-direct.h"
14
15/*
16 * I2C data (SDA) and clock (SCL) line read/writes with appropriate
17 * delays.
18 */
19
20static inline void setsda(struct efx_i2c_interface *i2c, int state)
21{
22 udelay(i2c->op->udelay);
23 i2c->sda = state;
24 i2c->op->setsda(i2c);
25 udelay(i2c->op->udelay);
26}
27
28static inline void setscl(struct efx_i2c_interface *i2c, int state)
29{
30 udelay(i2c->op->udelay);
31 i2c->scl = state;
32 i2c->op->setscl(i2c);
33 udelay(i2c->op->udelay);
34}
35
36static inline int getsda(struct efx_i2c_interface *i2c)
37{
38 int sda;
39
40 udelay(i2c->op->udelay);
41 sda = i2c->op->getsda(i2c);
42 udelay(i2c->op->udelay);
43 return sda;
44}
45
46static inline int getscl(struct efx_i2c_interface *i2c)
47{
48 int scl;
49
50 udelay(i2c->op->udelay);
51 scl = i2c->op->getscl(i2c);
52 udelay(i2c->op->udelay);
53 return scl;
54}
55
56/*
57 * I2C low-level protocol operations
58 *
59 */
60
61static inline void i2c_release(struct efx_i2c_interface *i2c)
62{
63 EFX_WARN_ON_PARANOID(!i2c->scl);
64 EFX_WARN_ON_PARANOID(!i2c->sda);
65 /* Devices may time out if operations do not end */
66 setscl(i2c, 1);
67 setsda(i2c, 1);
68 EFX_BUG_ON_PARANOID(getsda(i2c) != 1);
69 EFX_BUG_ON_PARANOID(getscl(i2c) != 1);
70}
71
72static inline void i2c_start(struct efx_i2c_interface *i2c)
73{
74 /* We may be restarting immediately after a {send,recv}_bit,
75 * so SCL will not necessarily already be high.
76 */
77 EFX_WARN_ON_PARANOID(!i2c->sda);
78 setscl(i2c, 1);
79 setsda(i2c, 0);
80 setscl(i2c, 0);
81 setsda(i2c, 1);
82}
83
84static inline void i2c_send_bit(struct efx_i2c_interface *i2c, int bit)
85{
86 EFX_WARN_ON_PARANOID(i2c->scl != 0);
87 setsda(i2c, bit);
88 setscl(i2c, 1);
89 setscl(i2c, 0);
90 setsda(i2c, 1);
91}
92
93static inline int i2c_recv_bit(struct efx_i2c_interface *i2c)
94{
95 int bit;
96
97 EFX_WARN_ON_PARANOID(i2c->scl != 0);
98 EFX_WARN_ON_PARANOID(!i2c->sda);
99 setscl(i2c, 1);
100 bit = getsda(i2c);
101 setscl(i2c, 0);
102 return bit;
103}
104
105static inline void i2c_stop(struct efx_i2c_interface *i2c)
106{
107 EFX_WARN_ON_PARANOID(i2c->scl != 0);
108 setsda(i2c, 0);
109 setscl(i2c, 1);
110 setsda(i2c, 1);
111}
112
113/*
114 * I2C mid-level protocol operations
115 *
116 */
117
118/* Sends a byte via the I2C bus and checks for an acknowledgement from
119 * the slave device.
120 */
121static int i2c_send_byte(struct efx_i2c_interface *i2c, u8 byte)
122{
123 int i;
124
125 /* Send byte */
126 for (i = 0; i < 8; i++) {
127 i2c_send_bit(i2c, !!(byte & 0x80));
128 byte <<= 1;
129 }
130
131 /* Check for acknowledgement from slave */
132 return (i2c_recv_bit(i2c) == 0 ? 0 : -EIO);
133}
134
135/* Receives a byte via the I2C bus and sends ACK/NACK to the slave device. */
136static u8 i2c_recv_byte(struct efx_i2c_interface *i2c, int ack)
137{
138 u8 value = 0;
139 int i;
140
141 /* Receive byte */
142 for (i = 0; i < 8; i++)
143 value = (value << 1) | i2c_recv_bit(i2c);
144
145 /* Send ACK/NACK */
146 i2c_send_bit(i2c, (ack ? 0 : 1));
147
148 return value;
149}
150
151/* Calculate command byte for a read operation */
152static inline u8 i2c_read_cmd(u8 device_id)
153{
154 return ((device_id << 1) | 1);
155}
156
157/* Calculate command byte for a write operation */
158static inline u8 i2c_write_cmd(u8 device_id)
159{
160 return ((device_id << 1) | 0);
161}
162
163int efx_i2c_check_presence(struct efx_i2c_interface *i2c, u8 device_id)
164{
165 int rc;
166
167 /* If someone is driving the bus low we just give up. */
168 if (getsda(i2c) == 0 || getscl(i2c) == 0) {
169 EFX_ERR(i2c->efx, "%s someone is holding the I2C bus low."
170 " Giving up.\n", __func__);
171 return -EFAULT;
172 }
173
174 /* Pretend to initiate a device write */
175 i2c_start(i2c);
176 rc = i2c_send_byte(i2c, i2c_write_cmd(device_id));
177 if (rc)
178 goto out;
179
180 out:
181 i2c_stop(i2c);
182 i2c_release(i2c);
183
184 return rc;
185}
186
187/* This performs a fast read of one or more consecutive bytes from an
188 * I2C device. Not all devices support consecutive reads of more than
189 * one byte; for these devices use efx_i2c_read() instead.
190 */
191int efx_i2c_fast_read(struct efx_i2c_interface *i2c,
192 u8 device_id, u8 offset, u8 *data, unsigned int len)
193{
194 int i;
195 int rc;
196
197 EFX_WARN_ON_PARANOID(getsda(i2c) != 1);
198 EFX_WARN_ON_PARANOID(getscl(i2c) != 1);
199 EFX_WARN_ON_PARANOID(data == NULL);
200 EFX_WARN_ON_PARANOID(len < 1);
201
202 /* Select device and starting offset */
203 i2c_start(i2c);
204 rc = i2c_send_byte(i2c, i2c_write_cmd(device_id));
205 if (rc)
206 goto out;
207 rc = i2c_send_byte(i2c, offset);
208 if (rc)
209 goto out;
210
211 /* Read data from device */
212 i2c_start(i2c);
213 rc = i2c_send_byte(i2c, i2c_read_cmd(device_id));
214 if (rc)
215 goto out;
216 for (i = 0; i < (len - 1); i++)
217 /* Read and acknowledge all but the last byte */
218 data[i] = i2c_recv_byte(i2c, 1);
219 /* Read last byte with no acknowledgement */
220 data[i] = i2c_recv_byte(i2c, 0);
221
222 out:
223 i2c_stop(i2c);
224 i2c_release(i2c);
225
226 return rc;
227}
228
229/* This performs a fast write of one or more consecutive bytes to an
230 * I2C device. Not all devices support consecutive writes of more
231 * than one byte; for these devices use efx_i2c_write() instead.
232 */
233int efx_i2c_fast_write(struct efx_i2c_interface *i2c,
234 u8 device_id, u8 offset,
235 const u8 *data, unsigned int len)
236{
237 int i;
238 int rc;
239
240 EFX_WARN_ON_PARANOID(getsda(i2c) != 1);
241 EFX_WARN_ON_PARANOID(getscl(i2c) != 1);
242 EFX_WARN_ON_PARANOID(len < 1);
243
244 /* Select device and starting offset */
245 i2c_start(i2c);
246 rc = i2c_send_byte(i2c, i2c_write_cmd(device_id));
247 if (rc)
248 goto out;
249 rc = i2c_send_byte(i2c, offset);
250 if (rc)
251 goto out;
252
253 /* Write data to device */
254 for (i = 0; i < len; i++) {
255 rc = i2c_send_byte(i2c, data[i]);
256 if (rc)
257 goto out;
258 }
259
260 out:
261 i2c_stop(i2c);
262 i2c_release(i2c);
263
264 return rc;
265}
266
267/* I2C byte-by-byte read */
268int efx_i2c_read(struct efx_i2c_interface *i2c,
269 u8 device_id, u8 offset, u8 *data, unsigned int len)
270{
271 int rc;
272
273 /* i2c_fast_read with length 1 is a single byte read */
274 for (; len > 0; offset++, data++, len--) {
275 rc = efx_i2c_fast_read(i2c, device_id, offset, data, 1);
276 if (rc)
277 return rc;
278 }
279
280 return 0;
281}
282
283/* I2C byte-by-byte write */
284int efx_i2c_write(struct efx_i2c_interface *i2c,
285 u8 device_id, u8 offset, const u8 *data, unsigned int len)
286{
287 int rc;
288
289 /* i2c_fast_write with length 1 is a single byte write */
290 for (; len > 0; offset++, data++, len--) {
291 rc = efx_i2c_fast_write(i2c, device_id, offset, data, 1);
292 if (rc)
293 return rc;
294 mdelay(i2c->op->mdelay);
295 }
296
297 return 0;
298}
299
300
301/* This is just a slightly neater wrapper round efx_i2c_fast_write
302 * in the case where the target doesn't take an offset
303 */
304int efx_i2c_send_bytes(struct efx_i2c_interface *i2c,
305 u8 device_id, const u8 *data, unsigned int len)
306{
307 return efx_i2c_fast_write(i2c, device_id, data[0], data + 1, len - 1);
308}
309
310/* I2C receiving of bytes - does not send an offset byte */
311int efx_i2c_recv_bytes(struct efx_i2c_interface *i2c, u8 device_id,
312 u8 *bytes, unsigned int len)
313{
314 int i;
315 int rc;
316
317 EFX_WARN_ON_PARANOID(getsda(i2c) != 1);
318 EFX_WARN_ON_PARANOID(getscl(i2c) != 1);
319 EFX_WARN_ON_PARANOID(len < 1);
320
321 /* Select device */
322 i2c_start(i2c);
323
324 /* Read data from device */
325 rc = i2c_send_byte(i2c, i2c_read_cmd(device_id));
326 if (rc)
327 goto out;
328
329 for (i = 0; i < (len - 1); i++)
330 /* Read and acknowledge all but the last byte */
331 bytes[i] = i2c_recv_byte(i2c, 1);
332 /* Read last byte with no acknowledgement */
333 bytes[i] = i2c_recv_byte(i2c, 0);
334
335 out:
336 i2c_stop(i2c);
337 i2c_release(i2c);
338
339 return rc;
340}
341
342/* SMBus and some I2C devices will time out if the I2C clock is
343 * held low for too long. This is most likely to happen in virtualised
344 * systems (when the entire domain is descheduled) but could in
345 * principle happen due to preemption on any busy system (and given the
346 * potential length of an I2C operation turning preemption off is not
347 * a sensible option). The following functions deal with the failure by
348 * retrying up to a fixed number of times.
349 */
350
351#define I2C_MAX_RETRIES (10)
352
353/* The timeout problem will result in -EIO. If the wrapped function
354 * returns any other error, pass this up and do not retry. */
355#define RETRY_WRAPPER(_f) \
356 int retries = I2C_MAX_RETRIES; \
357 int rc; \
358 while (retries) { \
359 rc = _f; \
360 if (rc != -EIO) \
361 return rc; \
362 retries--; \
363 } \
364 return rc; \
365
366int efx_i2c_check_presence_retry(struct efx_i2c_interface *i2c, u8 device_id)
367{
368 RETRY_WRAPPER(efx_i2c_check_presence(i2c, device_id))
369}
370
371int efx_i2c_read_retry(struct efx_i2c_interface *i2c,
372 u8 device_id, u8 offset, u8 *data, unsigned int len)
373{
374 RETRY_WRAPPER(efx_i2c_read(i2c, device_id, offset, data, len))
375}
376
377int efx_i2c_write_retry(struct efx_i2c_interface *i2c,
378 u8 device_id, u8 offset, const u8 *data, unsigned int len)
379{
380 RETRY_WRAPPER(efx_i2c_write(i2c, device_id, offset, data, len))
381}
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