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1 | /* | |
2 | * w1_ds2408.c - w1 family 29 (DS2408) driver | |
3 | * | |
4 | * Copyright (c) 2010 Jean-Francois Dagenais <dagenaisj@sonatest.com> | |
5 | * | |
6 | * This source code is licensed under the GNU General Public License, | |
7 | * Version 2. See the file COPYING for more details. | |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/moduleparam.h> | |
13 | #include <linux/device.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/delay.h> | |
16 | #include <linux/slab.h> | |
17 | ||
18 | #include "../w1.h" | |
19 | #include "../w1_int.h" | |
20 | #include "../w1_family.h" | |
21 | ||
22 | MODULE_LICENSE("GPL"); | |
23 | MODULE_AUTHOR("Jean-Francois Dagenais <dagenaisj@sonatest.com>"); | |
24 | MODULE_DESCRIPTION("w1 family 29 driver for DS2408 8 Pin IO"); | |
25 | MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2408)); | |
26 | ||
27 | ||
28 | #define W1_F29_RETRIES 3 | |
29 | ||
30 | #define W1_F29_REG_LOGIG_STATE 0x88 /* R */ | |
31 | #define W1_F29_REG_OUTPUT_LATCH_STATE 0x89 /* R */ | |
32 | #define W1_F29_REG_ACTIVITY_LATCH_STATE 0x8A /* R */ | |
33 | #define W1_F29_REG_COND_SEARCH_SELECT_MASK 0x8B /* RW */ | |
34 | #define W1_F29_REG_COND_SEARCH_POL_SELECT 0x8C /* RW */ | |
35 | #define W1_F29_REG_CONTROL_AND_STATUS 0x8D /* RW */ | |
36 | ||
37 | #define W1_F29_FUNC_READ_PIO_REGS 0xF0 | |
38 | #define W1_F29_FUNC_CHANN_ACCESS_READ 0xF5 | |
39 | #define W1_F29_FUNC_CHANN_ACCESS_WRITE 0x5A | |
40 | /* also used to write the control/status reg (0x8D): */ | |
41 | #define W1_F29_FUNC_WRITE_COND_SEARCH_REG 0xCC | |
42 | #define W1_F29_FUNC_RESET_ACTIVITY_LATCHES 0xC3 | |
43 | ||
44 | #define W1_F29_SUCCESS_CONFIRM_BYTE 0xAA | |
45 | ||
46 | static int _read_reg(struct w1_slave *sl, u8 address, unsigned char* buf) | |
47 | { | |
48 | u8 wrbuf[3]; | |
49 | dev_dbg(&sl->dev, | |
50 | "Reading with slave: %p, reg addr: %0#4x, buff addr: %p", | |
51 | sl, (unsigned int)address, buf); | |
52 | ||
53 | if (!buf) | |
54 | return -EINVAL; | |
55 | ||
56 | mutex_lock(&sl->master->bus_mutex); | |
57 | dev_dbg(&sl->dev, "mutex locked"); | |
58 | ||
59 | if (w1_reset_select_slave(sl)) { | |
60 | mutex_unlock(&sl->master->bus_mutex); | |
61 | return -EIO; | |
62 | } | |
63 | ||
64 | wrbuf[0] = W1_F29_FUNC_READ_PIO_REGS; | |
65 | wrbuf[1] = address; | |
66 | wrbuf[2] = 0; | |
67 | w1_write_block(sl->master, wrbuf, 3); | |
68 | *buf = w1_read_8(sl->master); | |
69 | ||
70 | mutex_unlock(&sl->master->bus_mutex); | |
71 | dev_dbg(&sl->dev, "mutex unlocked"); | |
72 | return 1; | |
73 | } | |
74 | ||
75 | static ssize_t state_read(struct file *filp, struct kobject *kobj, | |
76 | struct bin_attribute *bin_attr, char *buf, loff_t off, | |
77 | size_t count) | |
78 | { | |
79 | dev_dbg(&kobj_to_w1_slave(kobj)->dev, | |
80 | "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p", | |
81 | bin_attr->attr.name, kobj, (unsigned int)off, count, buf); | |
82 | if (count != 1 || off != 0) | |
83 | return -EFAULT; | |
84 | return _read_reg(kobj_to_w1_slave(kobj), W1_F29_REG_LOGIG_STATE, buf); | |
85 | } | |
86 | ||
87 | static ssize_t output_read(struct file *filp, struct kobject *kobj, | |
88 | struct bin_attribute *bin_attr, char *buf, | |
89 | loff_t off, size_t count) | |
90 | { | |
91 | dev_dbg(&kobj_to_w1_slave(kobj)->dev, | |
92 | "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p", | |
93 | bin_attr->attr.name, kobj, (unsigned int)off, count, buf); | |
94 | if (count != 1 || off != 0) | |
95 | return -EFAULT; | |
96 | return _read_reg(kobj_to_w1_slave(kobj), | |
97 | W1_F29_REG_OUTPUT_LATCH_STATE, buf); | |
98 | } | |
99 | ||
100 | static ssize_t activity_read(struct file *filp, struct kobject *kobj, | |
101 | struct bin_attribute *bin_attr, char *buf, | |
102 | loff_t off, size_t count) | |
103 | { | |
104 | dev_dbg(&kobj_to_w1_slave(kobj)->dev, | |
105 | "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p", | |
106 | bin_attr->attr.name, kobj, (unsigned int)off, count, buf); | |
107 | if (count != 1 || off != 0) | |
108 | return -EFAULT; | |
109 | return _read_reg(kobj_to_w1_slave(kobj), | |
110 | W1_F29_REG_ACTIVITY_LATCH_STATE, buf); | |
111 | } | |
112 | ||
113 | static ssize_t cond_search_mask_read(struct file *filp, struct kobject *kobj, | |
114 | struct bin_attribute *bin_attr, char *buf, | |
115 | loff_t off, size_t count) | |
116 | { | |
117 | dev_dbg(&kobj_to_w1_slave(kobj)->dev, | |
118 | "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p", | |
119 | bin_attr->attr.name, kobj, (unsigned int)off, count, buf); | |
120 | if (count != 1 || off != 0) | |
121 | return -EFAULT; | |
122 | return _read_reg(kobj_to_w1_slave(kobj), | |
123 | W1_F29_REG_COND_SEARCH_SELECT_MASK, buf); | |
124 | } | |
125 | ||
126 | static ssize_t cond_search_polarity_read(struct file *filp, | |
127 | struct kobject *kobj, | |
128 | struct bin_attribute *bin_attr, | |
129 | char *buf, loff_t off, size_t count) | |
130 | { | |
131 | if (count != 1 || off != 0) | |
132 | return -EFAULT; | |
133 | return _read_reg(kobj_to_w1_slave(kobj), | |
134 | W1_F29_REG_COND_SEARCH_POL_SELECT, buf); | |
135 | } | |
136 | ||
137 | static ssize_t status_control_read(struct file *filp, struct kobject *kobj, | |
138 | struct bin_attribute *bin_attr, char *buf, | |
139 | loff_t off, size_t count) | |
140 | { | |
141 | if (count != 1 || off != 0) | |
142 | return -EFAULT; | |
143 | return _read_reg(kobj_to_w1_slave(kobj), | |
144 | W1_F29_REG_CONTROL_AND_STATUS, buf); | |
145 | } | |
146 | ||
147 | static ssize_t output_write(struct file *filp, struct kobject *kobj, | |
148 | struct bin_attribute *bin_attr, char *buf, | |
149 | loff_t off, size_t count) | |
150 | { | |
151 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
152 | u8 w1_buf[3]; | |
153 | u8 readBack; | |
154 | unsigned int retries = W1_F29_RETRIES; | |
155 | ||
156 | if (count != 1 || off != 0) | |
157 | return -EFAULT; | |
158 | ||
159 | dev_dbg(&sl->dev, "locking mutex for write_output"); | |
160 | mutex_lock(&sl->master->bus_mutex); | |
161 | dev_dbg(&sl->dev, "mutex locked"); | |
162 | ||
163 | if (w1_reset_select_slave(sl)) | |
164 | goto error; | |
165 | ||
166 | while (retries--) { | |
167 | w1_buf[0] = W1_F29_FUNC_CHANN_ACCESS_WRITE; | |
168 | w1_buf[1] = *buf; | |
169 | w1_buf[2] = ~(*buf); | |
170 | w1_write_block(sl->master, w1_buf, 3); | |
171 | ||
172 | readBack = w1_read_8(sl->master); | |
173 | ||
174 | if (readBack != W1_F29_SUCCESS_CONFIRM_BYTE) { | |
175 | if (w1_reset_resume_command(sl->master)) | |
176 | goto error; | |
177 | /* try again, the slave is ready for a command */ | |
178 | continue; | |
179 | } | |
180 | ||
181 | #ifdef CONFIG_W1_SLAVE_DS2408_READBACK | |
182 | /* here the master could read another byte which | |
183 | would be the PIO reg (the actual pin logic state) | |
184 | since in this driver we don't know which pins are | |
185 | in and outs, there's no value to read the state and | |
186 | compare. with (*buf) so end this command abruptly: */ | |
187 | if (w1_reset_resume_command(sl->master)) | |
188 | goto error; | |
189 | ||
190 | /* go read back the output latches */ | |
191 | /* (the direct effect of the write above) */ | |
192 | w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS; | |
193 | w1_buf[1] = W1_F29_REG_OUTPUT_LATCH_STATE; | |
194 | w1_buf[2] = 0; | |
195 | w1_write_block(sl->master, w1_buf, 3); | |
196 | /* read the result of the READ_PIO_REGS command */ | |
197 | if (w1_read_8(sl->master) == *buf) | |
198 | #endif | |
199 | { | |
200 | /* success! */ | |
201 | mutex_unlock(&sl->master->bus_mutex); | |
202 | dev_dbg(&sl->dev, | |
203 | "mutex unlocked, retries:%d", retries); | |
204 | return 1; | |
205 | } | |
206 | } | |
207 | error: | |
208 | mutex_unlock(&sl->master->bus_mutex); | |
209 | dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries); | |
210 | ||
211 | return -EIO; | |
212 | } | |
213 | ||
214 | ||
215 | /** | |
216 | * Writing to the activity file resets the activity latches. | |
217 | */ | |
218 | static ssize_t activity_write(struct file *filp, struct kobject *kobj, | |
219 | struct bin_attribute *bin_attr, char *buf, | |
220 | loff_t off, size_t count) | |
221 | { | |
222 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
223 | unsigned int retries = W1_F29_RETRIES; | |
224 | ||
225 | if (count != 1 || off != 0) | |
226 | return -EFAULT; | |
227 | ||
228 | mutex_lock(&sl->master->bus_mutex); | |
229 | ||
230 | if (w1_reset_select_slave(sl)) | |
231 | goto error; | |
232 | ||
233 | while (retries--) { | |
234 | w1_write_8(sl->master, W1_F29_FUNC_RESET_ACTIVITY_LATCHES); | |
235 | if (w1_read_8(sl->master) == W1_F29_SUCCESS_CONFIRM_BYTE) { | |
236 | mutex_unlock(&sl->master->bus_mutex); | |
237 | return 1; | |
238 | } | |
239 | if (w1_reset_resume_command(sl->master)) | |
240 | goto error; | |
241 | } | |
242 | ||
243 | error: | |
244 | mutex_unlock(&sl->master->bus_mutex); | |
245 | return -EIO; | |
246 | } | |
247 | ||
248 | static ssize_t status_control_write(struct file *filp, struct kobject *kobj, | |
249 | struct bin_attribute *bin_attr, char *buf, | |
250 | loff_t off, size_t count) | |
251 | { | |
252 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
253 | u8 w1_buf[4]; | |
254 | unsigned int retries = W1_F29_RETRIES; | |
255 | ||
256 | if (count != 1 || off != 0) | |
257 | return -EFAULT; | |
258 | ||
259 | mutex_lock(&sl->master->bus_mutex); | |
260 | ||
261 | if (w1_reset_select_slave(sl)) | |
262 | goto error; | |
263 | ||
264 | while (retries--) { | |
265 | w1_buf[0] = W1_F29_FUNC_WRITE_COND_SEARCH_REG; | |
266 | w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS; | |
267 | w1_buf[2] = 0; | |
268 | w1_buf[3] = *buf; | |
269 | ||
270 | w1_write_block(sl->master, w1_buf, 4); | |
271 | if (w1_reset_resume_command(sl->master)) | |
272 | goto error; | |
273 | ||
274 | w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS; | |
275 | w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS; | |
276 | w1_buf[2] = 0; | |
277 | ||
278 | w1_write_block(sl->master, w1_buf, 3); | |
279 | if (w1_read_8(sl->master) == *buf) { | |
280 | /* success! */ | |
281 | mutex_unlock(&sl->master->bus_mutex); | |
282 | return 1; | |
283 | } | |
284 | } | |
285 | error: | |
286 | mutex_unlock(&sl->master->bus_mutex); | |
287 | ||
288 | return -EIO; | |
289 | } | |
290 | ||
291 | /* | |
292 | * This is a special sequence we must do to ensure the P0 output is not stuck | |
293 | * in test mode. This is described in rev 2 of the ds2408's datasheet | |
294 | * (http://datasheets.maximintegrated.com/en/ds/DS2408.pdf) under | |
295 | * "APPLICATION INFORMATION/Power-up timing". | |
296 | */ | |
297 | static int w1_f29_disable_test_mode(struct w1_slave *sl) | |
298 | { | |
299 | int res; | |
300 | u8 magic[10] = {0x96, }; | |
301 | u64 rn = le64_to_cpu(*((u64*)&sl->reg_num)); | |
302 | ||
303 | memcpy(&magic[1], &rn, 8); | |
304 | magic[9] = 0x3C; | |
305 | ||
306 | mutex_lock(&sl->master->bus_mutex); | |
307 | ||
308 | res = w1_reset_bus(sl->master); | |
309 | if (res) | |
310 | goto out; | |
311 | w1_write_block(sl->master, magic, ARRAY_SIZE(magic)); | |
312 | ||
313 | res = w1_reset_bus(sl->master); | |
314 | out: | |
315 | mutex_unlock(&sl->master->bus_mutex); | |
316 | return res; | |
317 | } | |
318 | ||
319 | static BIN_ATTR_RO(state, 1); | |
320 | static BIN_ATTR_RW(output, 1); | |
321 | static BIN_ATTR_RW(activity, 1); | |
322 | static BIN_ATTR_RO(cond_search_mask, 1); | |
323 | static BIN_ATTR_RO(cond_search_polarity, 1); | |
324 | static BIN_ATTR_RW(status_control, 1); | |
325 | ||
326 | static struct bin_attribute *w1_f29_bin_attrs[] = { | |
327 | &bin_attr_state, | |
328 | &bin_attr_output, | |
329 | &bin_attr_activity, | |
330 | &bin_attr_cond_search_mask, | |
331 | &bin_attr_cond_search_polarity, | |
332 | &bin_attr_status_control, | |
333 | NULL, | |
334 | }; | |
335 | ||
336 | static const struct attribute_group w1_f29_group = { | |
337 | .bin_attrs = w1_f29_bin_attrs, | |
338 | }; | |
339 | ||
340 | static const struct attribute_group *w1_f29_groups[] = { | |
341 | &w1_f29_group, | |
342 | NULL, | |
343 | }; | |
344 | ||
345 | static struct w1_family_ops w1_f29_fops = { | |
346 | .add_slave = w1_f29_disable_test_mode, | |
347 | .groups = w1_f29_groups, | |
348 | }; | |
349 | ||
350 | static struct w1_family w1_family_29 = { | |
351 | .fid = W1_FAMILY_DS2408, | |
352 | .fops = &w1_f29_fops, | |
353 | }; | |
354 | ||
355 | static int __init w1_f29_init(void) | |
356 | { | |
357 | return w1_register_family(&w1_family_29); | |
358 | } | |
359 | ||
360 | static void __exit w1_f29_exit(void) | |
361 | { | |
362 | w1_unregister_family(&w1_family_29); | |
363 | } | |
364 | ||
365 | module_init(w1_f29_init); | |
366 | module_exit(w1_f29_exit); |