2 * w1_ds2433.c - w1 family 23 (DS2433) driver
4 * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
6 * This source code is licensed under the GNU General Public License,
7 * Version 2. See the file COPYING for more details.
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 #ifdef CONFIG_W1_F23_CRC
17 #include <linux/crc16.h>
23 #include "w1_family.h"
25 MODULE_LICENSE("GPL");
26 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
27 MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
29 #define W1_EEPROM_SIZE 512
30 #define W1_PAGE_COUNT 16
31 #define W1_PAGE_SIZE 32
32 #define W1_PAGE_BITS 5
33 #define W1_PAGE_MASK 0x1F
35 #define W1_F23_TIME 300
37 #define W1_F23_READ_EEPROM 0xF0
38 #define W1_F23_WRITE_SCRATCH 0x0F
39 #define W1_F23_READ_SCRATCH 0xAA
40 #define W1_F23_COPY_SCRATCH 0x55
43 u8 memory[W1_EEPROM_SIZE];
48 * Check the file size bounds and adjusts count as needed.
49 * This would not be needed if the file size didn't reset to 0 after a write.
51 static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
56 if ((off + count) > size)
62 #ifdef CONFIG_W1_F23_CRC
63 static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
67 int off = block * W1_PAGE_SIZE;
69 if (data->validcrc & (1 << block))
72 if (w1_reset_select_slave(sl)) {
77 wrbuf[0] = W1_F23_READ_EEPROM;
78 wrbuf[1] = off & 0xff;
80 w1_write_block(sl->master, wrbuf, 3);
81 w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
83 /* cache the block if the CRC is valid */
84 if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
85 data->validcrc |= (1 << block);
89 #endif /* CONFIG_W1_F23_CRC */
91 static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off,
94 struct w1_slave *sl = kobj_to_w1_slave(kobj);
95 #ifdef CONFIG_W1_F23_CRC
96 struct w1_f23_data *data = sl->family_data;
97 int i, min_page, max_page;
102 if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
105 atomic_inc(&sl->refcnt);
106 if (down_interruptible(&sl->master->mutex)) {
111 #ifdef CONFIG_W1_F23_CRC
113 min_page = (off >> W1_PAGE_BITS);
114 max_page = (off + count - 1) >> W1_PAGE_BITS;
115 for (i = min_page; i <= max_page; i++) {
116 if (w1_f23_refresh_block(sl, data, i)) {
121 memcpy(buf, &data->memory[off], count);
123 #else /* CONFIG_W1_F23_CRC */
125 /* read directly from the EEPROM */
126 if (w1_reset_select_slave(sl)) {
131 wrbuf[0] = W1_F23_READ_EEPROM;
132 wrbuf[1] = off & 0xff;
134 w1_write_block(sl->master, wrbuf, 3);
135 w1_read_block(sl->master, buf, count);
137 #endif /* CONFIG_W1_F23_CRC */
140 up(&sl->master->mutex);
142 atomic_dec(&sl->refcnt);
148 * Writes to the scratchpad and reads it back for verification.
149 * Then copies the scratchpad to EEPROM.
150 * The data must be on one page.
151 * The master must be locked.
153 * @param sl The slave structure
154 * @param addr Address for the write
155 * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
156 * @param data The data to write
157 * @return 0=Success -1=failure
159 static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
162 u8 rdbuf[W1_PAGE_SIZE + 3];
163 u8 es = (addr + len - 1) & 0x1f;
165 /* Write the data to the scratchpad */
166 if (w1_reset_select_slave(sl))
169 wrbuf[0] = W1_F23_WRITE_SCRATCH;
170 wrbuf[1] = addr & 0xff;
171 wrbuf[2] = addr >> 8;
173 w1_write_block(sl->master, wrbuf, 3);
174 w1_write_block(sl->master, data, len);
176 /* Read the scratchpad and verify */
177 if (w1_reset_select_slave(sl))
180 w1_write_8(sl->master, W1_F23_READ_SCRATCH);
181 w1_read_block(sl->master, rdbuf, len + 3);
183 /* Compare what was read against the data written */
184 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
185 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
188 /* Copy the scratchpad to EEPROM */
189 if (w1_reset_select_slave(sl))
192 wrbuf[0] = W1_F23_COPY_SCRATCH;
194 w1_write_block(sl->master, wrbuf, 4);
196 /* Sleep for 5 ms to wait for the write to complete */
199 /* Reset the bus to wake up the EEPROM (this may not be needed) */
200 w1_reset_bus(sl->master);
205 static ssize_t w1_f23_write_bin(struct kobject *kobj, char *buf, loff_t off,
208 struct w1_slave *sl = kobj_to_w1_slave(kobj);
211 if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
214 #ifdef CONFIG_W1_F23_CRC
215 /* can only write full blocks in cached mode */
216 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
217 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%d\n",
222 /* make sure the block CRCs are valid */
223 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
224 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
225 dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
229 #endif /* CONFIG_W1_F23_CRC */
231 atomic_inc(&sl->refcnt);
232 if (down_interruptible(&sl->master->mutex)) {
237 /* Can only write data to one page at a time */
239 while (idx < count) {
241 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
242 if (len > (count - idx))
245 if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
253 up(&sl->master->mutex);
255 atomic_dec(&sl->refcnt);
260 static struct bin_attribute w1_f23_bin_attr = {
263 .mode = S_IRUGO | S_IWUSR,
264 .owner = THIS_MODULE,
266 .size = W1_EEPROM_SIZE,
267 .read = w1_f23_read_bin,
268 .write = w1_f23_write_bin,
271 static int w1_f23_add_slave(struct w1_slave *sl)
274 #ifdef CONFIG_W1_F23_CRC
275 struct w1_f23_data *data;
277 data = kmalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
280 memset(data, 0, sizeof(struct w1_f23_data));
281 sl->family_data = data;
283 #endif /* CONFIG_W1_F23_CRC */
285 err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
287 #ifdef CONFIG_W1_F23_CRC
290 #endif /* CONFIG_W1_F23_CRC */
295 static void w1_f23_remove_slave(struct w1_slave *sl)
297 #ifdef CONFIG_W1_F23_CRC
298 if (sl->family_data) {
299 kfree(sl->family_data);
300 sl->family_data = NULL;
302 #endif /* CONFIG_W1_F23_CRC */
303 sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
306 static struct w1_family_ops w1_f23_fops = {
307 .add_slave = w1_f23_add_slave,
308 .remove_slave = w1_f23_remove_slave,
311 static struct w1_family w1_family_23 = {
312 .fid = W1_EEPROM_DS2433,
313 .fops = &w1_f23_fops,
316 static int __init w1_f23_init(void)
318 return w1_register_family(&w1_family_23);
321 static void __exit w1_f23_fini(void)
323 w1_unregister_family(&w1_family_23);
326 module_init(w1_f23_init);
327 module_exit(w1_f23_fini);