diff options
author | Wolfram Sang <w.sang@pengutronix.de> | 2009-01-26 15:19:54 -0500 |
---|---|---|
committer | Jean Delvare <khali@linux-fr.org> | 2009-01-26 15:19:54 -0500 |
commit | e51d565ff6bb1cedc10568425511badf0633a212 (patch) | |
tree | c8bd2623f2b925e1c8fb451d022529410f9c3406 /drivers/misc/eeprom | |
parent | 2e157888f132131f8877affd2785dcee4c227c1d (diff) |
spi: Move at25 (for SPI eeproms) to /drivers/misc/eeprom
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'drivers/misc/eeprom')
-rw-r--r-- | drivers/misc/eeprom/Kconfig | 11 | ||||
-rw-r--r-- | drivers/misc/eeprom/Makefile | 1 | ||||
-rw-r--r-- | drivers/misc/eeprom/at25.c | 389 |
3 files changed, 401 insertions, 0 deletions
diff --git a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig index 3d31b6644245..5bf3c92d7162 100644 --- a/drivers/misc/eeprom/Kconfig +++ b/drivers/misc/eeprom/Kconfig | |||
@@ -26,6 +26,17 @@ config AT24 | |||
26 | This driver can also be built as a module. If so, the module | 26 | This driver can also be built as a module. If so, the module |
27 | will be called at24. | 27 | will be called at24. |
28 | 28 | ||
29 | config SPI_AT25 | ||
30 | tristate "SPI EEPROMs from most vendors" | ||
31 | depends on SPI && SYSFS | ||
32 | help | ||
33 | Enable this driver to get read/write support to most SPI EEPROMs, | ||
34 | after you configure the board init code to know about each eeprom | ||
35 | on your target board. | ||
36 | |||
37 | This driver can also be built as a module. If so, the module | ||
38 | will be called at25. | ||
39 | |||
29 | config SENSORS_EEPROM | 40 | config SENSORS_EEPROM |
30 | tristate "Old I2C EEPROM reader" | 41 | tristate "Old I2C EEPROM reader" |
31 | depends on I2C && EXPERIMENTAL | 42 | depends on I2C && EXPERIMENTAL |
diff --git a/drivers/misc/eeprom/Makefile b/drivers/misc/eeprom/Makefile index a3dad28f2724..a4fb5cf8ffe6 100644 --- a/drivers/misc/eeprom/Makefile +++ b/drivers/misc/eeprom/Makefile | |||
@@ -1,2 +1,3 @@ | |||
1 | obj-$(CONFIG_AT24) += at24.o | 1 | obj-$(CONFIG_AT24) += at24.o |
2 | obj-$(CONFIG_SPI_AT25) += at25.o | ||
2 | obj-$(CONFIG_SENSORS_EEPROM) += eeprom.o | 3 | obj-$(CONFIG_SENSORS_EEPROM) += eeprom.o |
diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c new file mode 100644 index 000000000000..290dbe99647a --- /dev/null +++ b/drivers/misc/eeprom/at25.c | |||
@@ -0,0 +1,389 @@ | |||
1 | /* | ||
2 | * at25.c -- support most SPI EEPROMs, such as Atmel AT25 models | ||
3 | * | ||
4 | * Copyright (C) 2006 David Brownell | ||
5 | * | ||
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 | |||
12 | #include <linux/kernel.h> | ||
13 | #include <linux/init.h> | ||
14 | #include <linux/module.h> | ||
15 | #include <linux/slab.h> | ||
16 | #include <linux/delay.h> | ||
17 | #include <linux/device.h> | ||
18 | #include <linux/sched.h> | ||
19 | |||
20 | #include <linux/spi/spi.h> | ||
21 | #include <linux/spi/eeprom.h> | ||
22 | |||
23 | |||
24 | /* | ||
25 | * NOTE: this is an *EEPROM* driver. The vagaries of product naming | ||
26 | * mean that some AT25 products are EEPROMs, and others are FLASH. | ||
27 | * Handle FLASH chips with the drivers/mtd/devices/m25p80.c driver, | ||
28 | * not this one! | ||
29 | */ | ||
30 | |||
31 | struct at25_data { | ||
32 | struct spi_device *spi; | ||
33 | struct mutex lock; | ||
34 | struct spi_eeprom chip; | ||
35 | struct bin_attribute bin; | ||
36 | unsigned addrlen; | ||
37 | }; | ||
38 | |||
39 | #define AT25_WREN 0x06 /* latch the write enable */ | ||
40 | #define AT25_WRDI 0x04 /* reset the write enable */ | ||
41 | #define AT25_RDSR 0x05 /* read status register */ | ||
42 | #define AT25_WRSR 0x01 /* write status register */ | ||
43 | #define AT25_READ 0x03 /* read byte(s) */ | ||
44 | #define AT25_WRITE 0x02 /* write byte(s)/sector */ | ||
45 | |||
46 | #define AT25_SR_nRDY 0x01 /* nRDY = write-in-progress */ | ||
47 | #define AT25_SR_WEN 0x02 /* write enable (latched) */ | ||
48 | #define AT25_SR_BP0 0x04 /* BP for software writeprotect */ | ||
49 | #define AT25_SR_BP1 0x08 | ||
50 | #define AT25_SR_WPEN 0x80 /* writeprotect enable */ | ||
51 | |||
52 | |||
53 | #define EE_MAXADDRLEN 3 /* 24 bit addresses, up to 2 MBytes */ | ||
54 | |||
55 | /* Specs often allow 5 msec for a page write, sometimes 20 msec; | ||
56 | * it's important to recover from write timeouts. | ||
57 | */ | ||
58 | #define EE_TIMEOUT 25 | ||
59 | |||
60 | /*-------------------------------------------------------------------------*/ | ||
61 | |||
62 | #define io_limit PAGE_SIZE /* bytes */ | ||
63 | |||
64 | static ssize_t | ||
65 | at25_ee_read( | ||
66 | struct at25_data *at25, | ||
67 | char *buf, | ||
68 | unsigned offset, | ||
69 | size_t count | ||
70 | ) | ||
71 | { | ||
72 | u8 command[EE_MAXADDRLEN + 1]; | ||
73 | u8 *cp; | ||
74 | ssize_t status; | ||
75 | struct spi_transfer t[2]; | ||
76 | struct spi_message m; | ||
77 | |||
78 | cp = command; | ||
79 | *cp++ = AT25_READ; | ||
80 | |||
81 | /* 8/16/24-bit address is written MSB first */ | ||
82 | switch (at25->addrlen) { | ||
83 | default: /* case 3 */ | ||
84 | *cp++ = offset >> 16; | ||
85 | case 2: | ||
86 | *cp++ = offset >> 8; | ||
87 | case 1: | ||
88 | case 0: /* can't happen: for better codegen */ | ||
89 | *cp++ = offset >> 0; | ||
90 | } | ||
91 | |||
92 | spi_message_init(&m); | ||
93 | memset(t, 0, sizeof t); | ||
94 | |||
95 | t[0].tx_buf = command; | ||
96 | t[0].len = at25->addrlen + 1; | ||
97 | spi_message_add_tail(&t[0], &m); | ||
98 | |||
99 | t[1].rx_buf = buf; | ||
100 | t[1].len = count; | ||
101 | spi_message_add_tail(&t[1], &m); | ||
102 | |||
103 | mutex_lock(&at25->lock); | ||
104 | |||
105 | /* Read it all at once. | ||
106 | * | ||
107 | * REVISIT that's potentially a problem with large chips, if | ||
108 | * other devices on the bus need to be accessed regularly or | ||
109 | * this chip is clocked very slowly | ||
110 | */ | ||
111 | status = spi_sync(at25->spi, &m); | ||
112 | dev_dbg(&at25->spi->dev, | ||
113 | "read %Zd bytes at %d --> %d\n", | ||
114 | count, offset, (int) status); | ||
115 | |||
116 | mutex_unlock(&at25->lock); | ||
117 | return status ? status : count; | ||
118 | } | ||
119 | |||
120 | static ssize_t | ||
121 | at25_bin_read(struct kobject *kobj, struct bin_attribute *bin_attr, | ||
122 | char *buf, loff_t off, size_t count) | ||
123 | { | ||
124 | struct device *dev; | ||
125 | struct at25_data *at25; | ||
126 | |||
127 | dev = container_of(kobj, struct device, kobj); | ||
128 | at25 = dev_get_drvdata(dev); | ||
129 | |||
130 | if (unlikely(off >= at25->bin.size)) | ||
131 | return 0; | ||
132 | if ((off + count) > at25->bin.size) | ||
133 | count = at25->bin.size - off; | ||
134 | if (unlikely(!count)) | ||
135 | return count; | ||
136 | |||
137 | return at25_ee_read(at25, buf, off, count); | ||
138 | } | ||
139 | |||
140 | |||
141 | static ssize_t | ||
142 | at25_ee_write(struct at25_data *at25, char *buf, loff_t off, size_t count) | ||
143 | { | ||
144 | ssize_t status = 0; | ||
145 | unsigned written = 0; | ||
146 | unsigned buf_size; | ||
147 | u8 *bounce; | ||
148 | |||
149 | /* Temp buffer starts with command and address */ | ||
150 | buf_size = at25->chip.page_size; | ||
151 | if (buf_size > io_limit) | ||
152 | buf_size = io_limit; | ||
153 | bounce = kmalloc(buf_size + at25->addrlen + 1, GFP_KERNEL); | ||
154 | if (!bounce) | ||
155 | return -ENOMEM; | ||
156 | |||
157 | /* For write, rollover is within the page ... so we write at | ||
158 | * most one page, then manually roll over to the next page. | ||
159 | */ | ||
160 | bounce[0] = AT25_WRITE; | ||
161 | mutex_lock(&at25->lock); | ||
162 | do { | ||
163 | unsigned long timeout, retries; | ||
164 | unsigned segment; | ||
165 | unsigned offset = (unsigned) off; | ||
166 | u8 *cp = bounce + 1; | ||
167 | |||
168 | *cp = AT25_WREN; | ||
169 | status = spi_write(at25->spi, cp, 1); | ||
170 | if (status < 0) { | ||
171 | dev_dbg(&at25->spi->dev, "WREN --> %d\n", | ||
172 | (int) status); | ||
173 | break; | ||
174 | } | ||
175 | |||
176 | /* 8/16/24-bit address is written MSB first */ | ||
177 | switch (at25->addrlen) { | ||
178 | default: /* case 3 */ | ||
179 | *cp++ = offset >> 16; | ||
180 | case 2: | ||
181 | *cp++ = offset >> 8; | ||
182 | case 1: | ||
183 | case 0: /* can't happen: for better codegen */ | ||
184 | *cp++ = offset >> 0; | ||
185 | } | ||
186 | |||
187 | /* Write as much of a page as we can */ | ||
188 | segment = buf_size - (offset % buf_size); | ||
189 | if (segment > count) | ||
190 | segment = count; | ||
191 | memcpy(cp, buf, segment); | ||
192 | status = spi_write(at25->spi, bounce, | ||
193 | segment + at25->addrlen + 1); | ||
194 | dev_dbg(&at25->spi->dev, | ||
195 | "write %u bytes at %u --> %d\n", | ||
196 | segment, offset, (int) status); | ||
197 | if (status < 0) | ||
198 | break; | ||
199 | |||
200 | /* REVISIT this should detect (or prevent) failed writes | ||
201 | * to readonly sections of the EEPROM... | ||
202 | */ | ||
203 | |||
204 | /* Wait for non-busy status */ | ||
205 | timeout = jiffies + msecs_to_jiffies(EE_TIMEOUT); | ||
206 | retries = 0; | ||
207 | do { | ||
208 | int sr; | ||
209 | |||
210 | sr = spi_w8r8(at25->spi, AT25_RDSR); | ||
211 | if (sr < 0 || (sr & AT25_SR_nRDY)) { | ||
212 | dev_dbg(&at25->spi->dev, | ||
213 | "rdsr --> %d (%02x)\n", sr, sr); | ||
214 | /* at HZ=100, this is sloooow */ | ||
215 | msleep(1); | ||
216 | continue; | ||
217 | } | ||
218 | if (!(sr & AT25_SR_nRDY)) | ||
219 | break; | ||
220 | } while (retries++ < 3 || time_before_eq(jiffies, timeout)); | ||
221 | |||
222 | if (time_after(jiffies, timeout)) { | ||
223 | dev_err(&at25->spi->dev, | ||
224 | "write %d bytes offset %d, " | ||
225 | "timeout after %u msecs\n", | ||
226 | segment, offset, | ||
227 | jiffies_to_msecs(jiffies - | ||
228 | (timeout - EE_TIMEOUT))); | ||
229 | status = -ETIMEDOUT; | ||
230 | break; | ||
231 | } | ||
232 | |||
233 | off += segment; | ||
234 | buf += segment; | ||
235 | count -= segment; | ||
236 | written += segment; | ||
237 | |||
238 | } while (count > 0); | ||
239 | |||
240 | mutex_unlock(&at25->lock); | ||
241 | |||
242 | kfree(bounce); | ||
243 | return written ? written : status; | ||
244 | } | ||
245 | |||
246 | static ssize_t | ||
247 | at25_bin_write(struct kobject *kobj, struct bin_attribute *bin_attr, | ||
248 | char *buf, loff_t off, size_t count) | ||
249 | { | ||
250 | struct device *dev; | ||
251 | struct at25_data *at25; | ||
252 | |||
253 | dev = container_of(kobj, struct device, kobj); | ||
254 | at25 = dev_get_drvdata(dev); | ||
255 | |||
256 | if (unlikely(off >= at25->bin.size)) | ||
257 | return -EFBIG; | ||
258 | if ((off + count) > at25->bin.size) | ||
259 | count = at25->bin.size - off; | ||
260 | if (unlikely(!count)) | ||
261 | return count; | ||
262 | |||
263 | return at25_ee_write(at25, buf, off, count); | ||
264 | } | ||
265 | |||
266 | /*-------------------------------------------------------------------------*/ | ||
267 | |||
268 | static int at25_probe(struct spi_device *spi) | ||
269 | { | ||
270 | struct at25_data *at25 = NULL; | ||
271 | const struct spi_eeprom *chip; | ||
272 | int err; | ||
273 | int sr; | ||
274 | int addrlen; | ||
275 | |||
276 | /* Chip description */ | ||
277 | chip = spi->dev.platform_data; | ||
278 | if (!chip) { | ||
279 | dev_dbg(&spi->dev, "no chip description\n"); | ||
280 | err = -ENODEV; | ||
281 | goto fail; | ||
282 | } | ||
283 | |||
284 | /* For now we only support 8/16/24 bit addressing */ | ||
285 | if (chip->flags & EE_ADDR1) | ||
286 | addrlen = 1; | ||
287 | else if (chip->flags & EE_ADDR2) | ||
288 | addrlen = 2; | ||
289 | else if (chip->flags & EE_ADDR3) | ||
290 | addrlen = 3; | ||
291 | else { | ||
292 | dev_dbg(&spi->dev, "unsupported address type\n"); | ||
293 | err = -EINVAL; | ||
294 | goto fail; | ||
295 | } | ||
296 | |||
297 | /* Ping the chip ... the status register is pretty portable, | ||
298 | * unlike probing manufacturer IDs. We do expect that system | ||
299 | * firmware didn't write it in the past few milliseconds! | ||
300 | */ | ||
301 | sr = spi_w8r8(spi, AT25_RDSR); | ||
302 | if (sr < 0 || sr & AT25_SR_nRDY) { | ||
303 | dev_dbg(&spi->dev, "rdsr --> %d (%02x)\n", sr, sr); | ||
304 | err = -ENXIO; | ||
305 | goto fail; | ||
306 | } | ||
307 | |||
308 | if (!(at25 = kzalloc(sizeof *at25, GFP_KERNEL))) { | ||
309 | err = -ENOMEM; | ||
310 | goto fail; | ||
311 | } | ||
312 | |||
313 | mutex_init(&at25->lock); | ||
314 | at25->chip = *chip; | ||
315 | at25->spi = spi_dev_get(spi); | ||
316 | dev_set_drvdata(&spi->dev, at25); | ||
317 | at25->addrlen = addrlen; | ||
318 | |||
319 | /* Export the EEPROM bytes through sysfs, since that's convenient. | ||
320 | * Default to root-only access to the data; EEPROMs often hold data | ||
321 | * that's sensitive for read and/or write, like ethernet addresses, | ||
322 | * security codes, board-specific manufacturing calibrations, etc. | ||
323 | */ | ||
324 | at25->bin.attr.name = "eeprom"; | ||
325 | at25->bin.attr.mode = S_IRUSR; | ||
326 | at25->bin.read = at25_bin_read; | ||
327 | |||
328 | at25->bin.size = at25->chip.byte_len; | ||
329 | if (!(chip->flags & EE_READONLY)) { | ||
330 | at25->bin.write = at25_bin_write; | ||
331 | at25->bin.attr.mode |= S_IWUSR; | ||
332 | } | ||
333 | |||
334 | err = sysfs_create_bin_file(&spi->dev.kobj, &at25->bin); | ||
335 | if (err) | ||
336 | goto fail; | ||
337 | |||
338 | dev_info(&spi->dev, "%Zd %s %s eeprom%s, pagesize %u\n", | ||
339 | (at25->bin.size < 1024) | ||
340 | ? at25->bin.size | ||
341 | : (at25->bin.size / 1024), | ||
342 | (at25->bin.size < 1024) ? "Byte" : "KByte", | ||
343 | at25->chip.name, | ||
344 | (chip->flags & EE_READONLY) ? " (readonly)" : "", | ||
345 | at25->chip.page_size); | ||
346 | return 0; | ||
347 | fail: | ||
348 | dev_dbg(&spi->dev, "probe err %d\n", err); | ||
349 | kfree(at25); | ||
350 | return err; | ||
351 | } | ||
352 | |||
353 | static int __devexit at25_remove(struct spi_device *spi) | ||
354 | { | ||
355 | struct at25_data *at25; | ||
356 | |||
357 | at25 = dev_get_drvdata(&spi->dev); | ||
358 | sysfs_remove_bin_file(&spi->dev.kobj, &at25->bin); | ||
359 | kfree(at25); | ||
360 | return 0; | ||
361 | } | ||
362 | |||
363 | /*-------------------------------------------------------------------------*/ | ||
364 | |||
365 | static struct spi_driver at25_driver = { | ||
366 | .driver = { | ||
367 | .name = "at25", | ||
368 | .owner = THIS_MODULE, | ||
369 | }, | ||
370 | .probe = at25_probe, | ||
371 | .remove = __devexit_p(at25_remove), | ||
372 | }; | ||
373 | |||
374 | static int __init at25_init(void) | ||
375 | { | ||
376 | return spi_register_driver(&at25_driver); | ||
377 | } | ||
378 | module_init(at25_init); | ||
379 | |||
380 | static void __exit at25_exit(void) | ||
381 | { | ||
382 | spi_unregister_driver(&at25_driver); | ||
383 | } | ||
384 | module_exit(at25_exit); | ||
385 | |||
386 | MODULE_DESCRIPTION("Driver for most SPI EEPROMs"); | ||
387 | MODULE_AUTHOR("David Brownell"); | ||
388 | MODULE_LICENSE("GPL"); | ||
389 | |||