2 * w1_ds2805 - w1 family 0d (DS28E05) driver
4 * Copyright (c) 2016 Andrew Worsley amworsley@gmail.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>
19 #define W1_EEPROM_DS2805 0x0D
21 #define W1_F0D_EEPROM_SIZE 128
22 #define W1_F0D_PAGE_BITS 3
23 #define W1_F0D_PAGE_SIZE (1<<W1_F0D_PAGE_BITS)
24 #define W1_F0D_PAGE_MASK 0x0F
26 #define W1_F0D_SCRATCH_BITS 1
27 #define W1_F0D_SCRATCH_SIZE (1<<W1_F0D_SCRATCH_BITS)
28 #define W1_F0D_SCRATCH_MASK (W1_F0D_SCRATCH_SIZE-1)
30 #define W1_F0D_READ_EEPROM 0xF0
31 #define W1_F0D_WRITE_EEPROM 0x55
32 #define W1_F0D_RELEASE 0xFF
34 #define W1_F0D_CS_OK 0xAA /* Chip Status Ok */
36 #define W1_F0D_TPROG_MS 16
38 #define W1_F0D_READ_RETRIES 10
39 #define W1_F0D_READ_MAXLEN W1_F0D_EEPROM_SIZE
42 * Check the file size bounds and adjusts count as needed.
43 * This would not be needed if the file size didn't reset to 0 after a write.
45 static inline size_t w1_f0d_fix_count(loff_t off, size_t count, size_t size)
50 if ((off + count) > size)
57 * Read a block from W1 ROM two times and compares the results.
58 * If they are equal they are returned, otherwise the read
59 * is repeated W1_F0D_READ_RETRIES times.
61 * count must not exceed W1_F0D_READ_MAXLEN.
63 static int w1_f0d_readblock(struct w1_slave *sl, int off, int count, char *buf)
66 u8 cmp[W1_F0D_READ_MAXLEN];
67 int tries = W1_F0D_READ_RETRIES;
70 wrbuf[0] = W1_F0D_READ_EEPROM;
71 wrbuf[1] = off & 0x7f;
74 if (w1_reset_select_slave(sl))
77 w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
78 w1_read_block(sl->master, buf, count);
80 if (w1_reset_select_slave(sl))
83 w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
84 w1_read_block(sl->master, cmp, count);
86 if (!memcmp(cmp, buf, count))
90 dev_err(&sl->dev, "proof reading failed %d times\n",
96 static ssize_t w1_f0d_read_bin(struct file *filp, struct kobject *kobj,
97 struct bin_attribute *bin_attr,
98 char *buf, loff_t off, size_t count)
100 struct w1_slave *sl = kobj_to_w1_slave(kobj);
103 count = w1_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE);
107 mutex_lock(&sl->master->mutex);
109 /* read directly from the EEPROM in chunks of W1_F0D_READ_MAXLEN */
113 if (todo >= W1_F0D_READ_MAXLEN)
114 block_read = W1_F0D_READ_MAXLEN;
118 if (w1_f0d_readblock(sl, off, block_read, buf) < 0) {
123 todo -= W1_F0D_READ_MAXLEN;
124 buf += W1_F0D_READ_MAXLEN;
125 off += W1_F0D_READ_MAXLEN;
128 mutex_unlock(&sl->master->mutex);
134 * Writes to the scratchpad and reads it back for verification.
135 * Then copies the scratchpad to EEPROM.
136 * The data must be aligned at W1_F0D_SCRATCH_SIZE bytes and
137 * must be W1_F0D_SCRATCH_SIZE bytes long.
138 * The master must be locked.
140 * @param sl The slave structure
141 * @param addr Address for the write
142 * @param len length must be <= (W1_F0D_PAGE_SIZE - (addr & W1_F0D_PAGE_MASK))
143 * @param data The data to write
144 * @return 0=Success -1=failure
146 static int w1_f0d_write(struct w1_slave *sl, int addr, int len, const u8 *data)
148 int tries = W1_F0D_READ_RETRIES;
150 u8 rdbuf[W1_F0D_SCRATCH_SIZE];
153 if ((addr & 1) || (len != 2)) {
154 dev_err(&sl->dev, "%s: bad addr/len - addr=%#x len=%d\n",
155 __func__, addr, len);
161 /* Write the data to the scratchpad */
162 if (w1_reset_select_slave(sl))
165 wrbuf[0] = W1_F0D_WRITE_EEPROM;
166 wrbuf[1] = addr & 0xff;
167 wrbuf[2] = 0xff; /* ?? from Example */
169 w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
170 w1_write_block(sl->master, data, len);
172 w1_read_block(sl->master, rdbuf, sizeof(rdbuf));
173 /* Compare what was read against the data written */
174 if ((rdbuf[0] != data[0]) || (rdbuf[1] != data[1])) {
180 "could not write to eeprom, scratchpad compare failed %d times\n",
181 W1_F0D_READ_RETRIES);
182 pr_info("%s: rdbuf = %#x %#x data = %#x %#x\n",
183 __func__, rdbuf[0], rdbuf[1], data[0], data[1]);
188 /* Trigger write out to EEPROM */
189 w1_write_8(sl->master, W1_F0D_RELEASE);
191 /* Sleep for tprog ms to wait for the write to complete */
192 msleep(W1_F0D_TPROG_MS);
194 /* Check CS (Command Status) == 0xAA ? */
195 cs = w1_read_8(sl->master);
196 if (cs != W1_F0D_CS_OK) {
197 dev_err(&sl->dev, "save to eeprom failed = CS=%#x\n", cs);
204 static ssize_t w1_f0d_write_bin(struct file *filp, struct kobject *kobj,
205 struct bin_attribute *bin_attr,
206 char *buf, loff_t off, size_t count)
208 struct w1_slave *sl = kobj_to_w1_slave(kobj);
212 count = w1_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE);
216 mutex_lock(&sl->master->mutex);
218 /* Can only write data in blocks of the size of the scratchpad */
223 /* if len too short or addr not aligned */
224 if (len < W1_F0D_SCRATCH_SIZE || addr & W1_F0D_SCRATCH_MASK) {
225 char tmp[W1_F0D_SCRATCH_SIZE];
227 /* read the block and update the parts to be written */
228 if (w1_f0d_readblock(sl, addr & ~W1_F0D_SCRATCH_MASK,
229 W1_F0D_SCRATCH_SIZE, tmp)) {
234 /* copy at most to the boundary of the PAGE or len */
235 copy = W1_F0D_SCRATCH_SIZE -
236 (addr & W1_F0D_SCRATCH_MASK);
241 memcpy(&tmp[addr & W1_F0D_SCRATCH_MASK], buf, copy);
242 if (w1_f0d_write(sl, addr & ~W1_F0D_SCRATCH_MASK,
243 W1_F0D_SCRATCH_SIZE, tmp) < 0) {
249 copy = W1_F0D_SCRATCH_SIZE;
250 if (w1_f0d_write(sl, addr, copy, buf) < 0) {
261 mutex_unlock(&sl->master->mutex);
266 static struct bin_attribute w1_f0d_bin_attr = {
269 .mode = S_IRUGO | S_IWUSR,
271 .size = W1_F0D_EEPROM_SIZE,
272 .read = w1_f0d_read_bin,
273 .write = w1_f0d_write_bin,
276 static int w1_f0d_add_slave(struct w1_slave *sl)
278 return sysfs_create_bin_file(&sl->dev.kobj, &w1_f0d_bin_attr);
281 static void w1_f0d_remove_slave(struct w1_slave *sl)
283 sysfs_remove_bin_file(&sl->dev.kobj, &w1_f0d_bin_attr);
286 static struct w1_family_ops w1_f0d_fops = {
287 .add_slave = w1_f0d_add_slave,
288 .remove_slave = w1_f0d_remove_slave,
291 static struct w1_family w1_family_2d = {
292 .fid = W1_EEPROM_DS2805,
293 .fops = &w1_f0d_fops,
296 static int __init w1_f0d_init(void)
298 pr_info("%s()\n", __func__);
299 return w1_register_family(&w1_family_2d);
302 static void __exit w1_f0d_fini(void)
304 pr_info("%s()\n", __func__);
305 w1_unregister_family(&w1_family_2d);
308 module_init(w1_f0d_init);
309 module_exit(w1_f0d_fini);
311 MODULE_LICENSE("GPL");
312 MODULE_AUTHOR("Andrew Worsley amworsley@gmail.com");
313 MODULE_DESCRIPTION("w1 family 0d driver for DS2805, 1kb EEPROM");