Commit | Line | Data |
---|---|---|
80895392 EP |
1 | /* |
2 | * w1_ds2433.c - w1 family 23 (DS2433) driver | |
3 | * | |
4 | * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the smems of the GNU General Public License as published by | |
8 | * the Free Software Foundation; version 2 of the License. | |
9 | */ | |
10 | ||
11 | #include <linux/kernel.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/moduleparam.h> | |
14 | #include <linux/device.h> | |
15 | #include <linux/types.h> | |
16 | #include <linux/delay.h> | |
17 | ||
18 | #include "w1.h" | |
19 | #include "w1_io.h" | |
20 | #include "w1_int.h" | |
21 | #include "w1_family.h" | |
22 | ||
23 | MODULE_LICENSE("GPL"); | |
24 | MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>"); | |
25 | MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM"); | |
26 | ||
27 | #define W1_EEPROM_SIZE 512 | |
28 | #define W1_PAGE_SIZE 32 | |
29 | #define W1_PAGE_BITS 5 | |
30 | #define W1_PAGE_MASK 0x1F | |
31 | ||
32 | #define W1_F23_READ_EEPROM 0xF0 | |
33 | #define W1_F23_WRITE_SCRATCH 0x0F | |
34 | #define W1_F23_READ_SCRATCH 0xAA | |
35 | #define W1_F23_COPY_SCRATCH 0x55 | |
36 | ||
37 | /** | |
38 | * Check the file size bounds and adjusts count as needed. | |
39 | * This may not be needed if the sysfs layer checks bounds. | |
40 | */ | |
41 | static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size) | |
42 | { | |
43 | if (off > size) | |
44 | return 0; | |
45 | ||
46 | if ((off + count) > size) | |
47 | return (size - off); | |
48 | ||
49 | return count; | |
50 | } | |
51 | ||
52 | static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count) | |
53 | { | |
54 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
55 | u8 wrbuf[3]; | |
56 | ||
57 | if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0) | |
58 | return 0; | |
59 | ||
60 | atomic_inc(&sl->refcnt); | |
61 | if (down_interruptible(&sl->master->mutex)) { | |
62 | count = 0; | |
63 | goto out_dec; | |
64 | } | |
65 | ||
66 | /* read directly from the EEPROM */ | |
67 | if (w1_reset_select_slave(sl)) { | |
68 | count = -EIO; | |
69 | goto out_up; | |
70 | } | |
71 | ||
72 | wrbuf[0] = W1_F23_READ_EEPROM; | |
73 | wrbuf[1] = off & 0xff; | |
74 | wrbuf[2] = off >> 8; | |
75 | w1_write_block(sl->master, wrbuf, 3); | |
76 | w1_read_block(sl->master, buf, count); | |
77 | ||
78 | out_up: | |
79 | up(&sl->master->mutex); | |
80 | out_dec: | |
81 | atomic_dec(&sl->refcnt); | |
82 | ||
83 | return count; | |
84 | } | |
85 | ||
86 | /** | |
87 | * Writes to the scratchpad and reads it back for verification. | |
88 | * The master must be locked. | |
89 | * | |
90 | * @param sl The slave structure | |
91 | * @param addr Address for the write | |
92 | * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) | |
93 | * @param data The data to write | |
94 | * @return 0=Success -1=failure | |
95 | */ | |
96 | static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data) | |
97 | { | |
98 | u8 wrbuf[4]; | |
99 | u8 rdbuf[W1_PAGE_SIZE + 3]; | |
100 | u8 es = (addr + len - 1) & 0x1f; | |
101 | ||
102 | /* Write the data to the scratchpad */ | |
103 | if (w1_reset_select_slave(sl)) | |
104 | return -1; | |
105 | ||
106 | wrbuf[0] = W1_F23_WRITE_SCRATCH; | |
107 | wrbuf[1] = addr & 0xff; | |
108 | wrbuf[2] = addr >> 8; | |
109 | ||
110 | w1_write_block(sl->master, wrbuf, 3); | |
111 | w1_write_block(sl->master, data, len); | |
112 | ||
113 | /* Read the scratchpad and verify */ | |
114 | if (w1_reset_select_slave(sl)) | |
115 | return -1; | |
116 | ||
117 | w1_write_8(sl->master, W1_F23_READ_SCRATCH); | |
118 | w1_read_block(sl->master, rdbuf, len + 3); | |
119 | ||
120 | /* Compare what was read against the data written */ | |
121 | if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || | |
122 | (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) | |
123 | return -1; | |
124 | ||
125 | /* Copy the scratchpad to EEPROM */ | |
126 | if (w1_reset_select_slave(sl)) | |
127 | return -1; | |
128 | ||
129 | wrbuf[0] = W1_F23_COPY_SCRATCH; | |
130 | wrbuf[3] = es; | |
131 | w1_write_block(sl->master, wrbuf, 4); | |
132 | ||
133 | /* Sleep for 5 ms to wait for the write to complete */ | |
134 | msleep(5); | |
135 | ||
136 | /* Reset the bus to wake up the EEPROM (this may not be needed) */ | |
137 | w1_reset_bus(sl->master); | |
138 | ||
139 | return 0; | |
140 | } | |
141 | ||
142 | static ssize_t w1_f23_write_bin(struct kobject *kobj, char *buf, loff_t off, | |
143 | size_t count) | |
144 | { | |
145 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
146 | int addr, len, idx; | |
147 | ||
148 | if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0) | |
149 | return 0; | |
150 | ||
151 | atomic_inc(&sl->refcnt); | |
152 | if (down_interruptible(&sl->master->mutex)) { | |
153 | count = 0; | |
154 | goto out_dec; | |
155 | } | |
156 | ||
157 | /* Can only write data to one page at a time */ | |
158 | idx = 0; | |
159 | while (idx < count) { | |
160 | addr = off + idx; | |
161 | len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK); | |
162 | if (len > (count - idx)) | |
163 | len = count - idx; | |
164 | ||
165 | if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) { | |
166 | count = -EIO; | |
167 | goto out_up; | |
168 | } | |
169 | idx += len; | |
170 | } | |
171 | ||
172 | out_up: | |
173 | up(&sl->master->mutex); | |
174 | out_dec: | |
175 | atomic_dec(&sl->refcnt); | |
176 | ||
177 | return count; | |
178 | } | |
179 | ||
180 | static struct bin_attribute w1_f23_bin_attr = { | |
181 | .attr = { | |
182 | .name = "eeprom", | |
183 | .mode = S_IRUGO | S_IWUSR, | |
184 | .owner = THIS_MODULE, | |
185 | }, | |
186 | .size = W1_EEPROM_SIZE, | |
187 | .read = w1_f23_read_bin, | |
188 | .write = w1_f23_write_bin, | |
189 | }; | |
190 | ||
191 | static int w1_f23_add_slave(struct w1_slave *sl) | |
192 | { | |
193 | return sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr); | |
194 | } | |
195 | ||
196 | static void w1_f23_remove_slave(struct w1_slave *sl) | |
197 | { | |
198 | sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr); | |
199 | } | |
200 | ||
201 | static struct w1_family_ops w1_f23_fops = { | |
202 | .add_slave = w1_f23_add_slave, | |
203 | .remove_slave = w1_f23_remove_slave, | |
204 | }; | |
205 | ||
206 | static struct w1_family w1_family_23 = { | |
207 | .fid = W1_EEPROM_DS2433, | |
208 | .fops = &w1_f23_fops, | |
209 | }; | |
210 | ||
211 | static int __init w1_f23_init(void) | |
212 | { | |
213 | return w1_register_family(&w1_family_23); | |
214 | } | |
215 | ||
216 | static void __exit w1_f23_fini(void) | |
217 | { | |
218 | w1_unregister_family(&w1_family_23); | |
219 | } | |
220 | ||
221 | module_init(w1_f23_init); | |
222 | module_exit(w1_f23_fini); |