1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * w1_ds2805 - w1 family 0d (DS28E05) driver 4 * 5 * Copyright (c) 2016 Andrew Worsley amworsley@gmail.com 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/moduleparam.h> 11 #include <linux/device.h> 12 #include <linux/types.h> 13 #include <linux/delay.h> 14 15 #include <linux/w1.h> 16 17 #define W1_EEPROM_DS2805 0x0D 18 19 #define W1_F0D_EEPROM_SIZE 128 20 #define W1_F0D_PAGE_BITS 3 21 #define W1_F0D_PAGE_SIZE (1<<W1_F0D_PAGE_BITS) 22 #define W1_F0D_PAGE_MASK 0x0F 23 24 #define W1_F0D_SCRATCH_BITS 1 25 #define W1_F0D_SCRATCH_SIZE (1<<W1_F0D_SCRATCH_BITS) 26 #define W1_F0D_SCRATCH_MASK (W1_F0D_SCRATCH_SIZE-1) 27 28 #define W1_F0D_READ_EEPROM 0xF0 29 #define W1_F0D_WRITE_EEPROM 0x55 30 #define W1_F0D_RELEASE 0xFF 31 32 #define W1_F0D_CS_OK 0xAA /* Chip Status Ok */ 33 34 #define W1_F0D_TPROG_MS 16 35 36 #define W1_F0D_READ_RETRIES 10 37 #define W1_F0D_READ_MAXLEN W1_F0D_EEPROM_SIZE 38 39 /* 40 * Check the file size bounds and adjusts count as needed. 41 * This would not be needed if the file size didn't reset to 0 after a write. 42 */ 43 static inline size_t w1_f0d_fix_count(loff_t off, size_t count, size_t size) 44 { 45 if (off > size) 46 return 0; 47 48 if ((off + count) > size) 49 return size - off; 50 51 return count; 52 } 53 54 /* 55 * Read a block from W1 ROM two times and compares the results. 56 * If they are equal they are returned, otherwise the read 57 * is repeated W1_F0D_READ_RETRIES times. 58 * 59 * count must not exceed W1_F0D_READ_MAXLEN. 60 */ 61 static int w1_f0d_readblock(struct w1_slave *sl, int off, int count, char *buf) 62 { 63 u8 wrbuf[3]; 64 u8 cmp[W1_F0D_READ_MAXLEN]; 65 int tries = W1_F0D_READ_RETRIES; 66 67 do { 68 wrbuf[0] = W1_F0D_READ_EEPROM; 69 wrbuf[1] = off & 0x7f; 70 wrbuf[2] = 0; 71 72 if (w1_reset_select_slave(sl)) 73 return -1; 74 75 w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); 76 w1_read_block(sl->master, buf, count); 77 78 if (w1_reset_select_slave(sl)) 79 return -1; 80 81 w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); 82 w1_read_block(sl->master, cmp, count); 83 84 if (!memcmp(cmp, buf, count)) 85 return 0; 86 } while (--tries); 87 88 dev_err(&sl->dev, "proof reading failed %d times\n", 89 W1_F0D_READ_RETRIES); 90 91 return -1; 92 } 93 94 static ssize_t w1_f0d_read_bin(struct file *filp, struct kobject *kobj, 95 struct bin_attribute *bin_attr, 96 char *buf, loff_t off, size_t count) 97 { 98 struct w1_slave *sl = kobj_to_w1_slave(kobj); 99 int todo = count; 100 101 count = w1_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE); 102 if (count == 0) 103 return 0; 104 105 mutex_lock(&sl->master->mutex); 106 107 /* read directly from the EEPROM in chunks of W1_F0D_READ_MAXLEN */ 108 while (todo > 0) { 109 int block_read; 110 111 if (todo >= W1_F0D_READ_MAXLEN) 112 block_read = W1_F0D_READ_MAXLEN; 113 else 114 block_read = todo; 115 116 if (w1_f0d_readblock(sl, off, block_read, buf) < 0) { 117 count = -EIO; 118 break; 119 } 120 121 todo -= W1_F0D_READ_MAXLEN; 122 buf += W1_F0D_READ_MAXLEN; 123 off += W1_F0D_READ_MAXLEN; 124 } 125 126 mutex_unlock(&sl->master->mutex); 127 128 return count; 129 } 130 131 /* 132 * Writes to the scratchpad and reads it back for verification. 133 * Then copies the scratchpad to EEPROM. 134 * The data must be aligned at W1_F0D_SCRATCH_SIZE bytes and 135 * must be W1_F0D_SCRATCH_SIZE bytes long. 136 * The master must be locked. 137 * 138 * @param sl The slave structure 139 * @param addr Address for the write 140 * @param len length must be <= (W1_F0D_PAGE_SIZE - (addr & W1_F0D_PAGE_MASK)) 141 * @param data The data to write 142 * @return 0=Success -1=failure 143 */ 144 static int w1_f0d_write(struct w1_slave *sl, int addr, int len, const u8 *data) 145 { 146 int tries = W1_F0D_READ_RETRIES; 147 u8 wrbuf[3]; 148 u8 rdbuf[W1_F0D_SCRATCH_SIZE]; 149 u8 cs; 150 151 if ((addr & 1) || (len != 2)) { 152 dev_err(&sl->dev, "%s: bad addr/len - addr=%#x len=%d\n", 153 __func__, addr, len); 154 return -1; 155 } 156 157 retry: 158 159 /* Write the data to the scratchpad */ 160 if (w1_reset_select_slave(sl)) 161 return -1; 162 163 wrbuf[0] = W1_F0D_WRITE_EEPROM; 164 wrbuf[1] = addr & 0xff; 165 wrbuf[2] = 0xff; /* ?? from Example */ 166 167 w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); 168 w1_write_block(sl->master, data, len); 169 170 w1_read_block(sl->master, rdbuf, sizeof(rdbuf)); 171 /* Compare what was read against the data written */ 172 if ((rdbuf[0] != data[0]) || (rdbuf[1] != data[1])) { 173 174 if (--tries) 175 goto retry; 176 177 dev_err(&sl->dev, 178 "could not write to eeprom, scratchpad compare failed %d times\n", 179 W1_F0D_READ_RETRIES); 180 pr_info("%s: rdbuf = %#x %#x data = %#x %#x\n", 181 __func__, rdbuf[0], rdbuf[1], data[0], data[1]); 182 183 return -1; 184 } 185 186 /* Trigger write out to EEPROM */ 187 w1_write_8(sl->master, W1_F0D_RELEASE); 188 189 /* Sleep for tprog ms to wait for the write to complete */ 190 msleep(W1_F0D_TPROG_MS); 191 192 /* Check CS (Command Status) == 0xAA ? */ 193 cs = w1_read_8(sl->master); 194 if (cs != W1_F0D_CS_OK) { 195 dev_err(&sl->dev, "save to eeprom failed = CS=%#x\n", cs); 196 return -1; 197 } 198 199 return 0; 200 } 201 202 static ssize_t w1_f0d_write_bin(struct file *filp, struct kobject *kobj, 203 struct bin_attribute *bin_attr, 204 char *buf, loff_t off, size_t count) 205 { 206 struct w1_slave *sl = kobj_to_w1_slave(kobj); 207 int addr, len; 208 int copy; 209 210 count = w1_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE); 211 if (count == 0) 212 return 0; 213 214 mutex_lock(&sl->master->mutex); 215 216 /* Can only write data in blocks of the size of the scratchpad */ 217 addr = off; 218 len = count; 219 while (len > 0) { 220 221 /* if len too short or addr not aligned */ 222 if (len < W1_F0D_SCRATCH_SIZE || addr & W1_F0D_SCRATCH_MASK) { 223 char tmp[W1_F0D_SCRATCH_SIZE]; 224 225 /* read the block and update the parts to be written */ 226 if (w1_f0d_readblock(sl, addr & ~W1_F0D_SCRATCH_MASK, 227 W1_F0D_SCRATCH_SIZE, tmp)) { 228 count = -EIO; 229 goto out_up; 230 } 231 232 /* copy at most to the boundary of the PAGE or len */ 233 copy = W1_F0D_SCRATCH_SIZE - 234 (addr & W1_F0D_SCRATCH_MASK); 235 236 if (copy > len) 237 copy = len; 238 239 memcpy(&tmp[addr & W1_F0D_SCRATCH_MASK], buf, copy); 240 if (w1_f0d_write(sl, addr & ~W1_F0D_SCRATCH_MASK, 241 W1_F0D_SCRATCH_SIZE, tmp) < 0) { 242 count = -EIO; 243 goto out_up; 244 } 245 } else { 246 247 copy = W1_F0D_SCRATCH_SIZE; 248 if (w1_f0d_write(sl, addr, copy, buf) < 0) { 249 count = -EIO; 250 goto out_up; 251 } 252 } 253 buf += copy; 254 addr += copy; 255 len -= copy; 256 } 257 258 out_up: 259 mutex_unlock(&sl->master->mutex); 260 261 return count; 262 } 263 264 static struct bin_attribute w1_f0d_bin_attr = { 265 .attr = { 266 .name = "eeprom", 267 .mode = S_IRUGO | S_IWUSR, 268 }, 269 .size = W1_F0D_EEPROM_SIZE, 270 .read = w1_f0d_read_bin, 271 .write = w1_f0d_write_bin, 272 }; 273 274 static int w1_f0d_add_slave(struct w1_slave *sl) 275 { 276 return sysfs_create_bin_file(&sl->dev.kobj, &w1_f0d_bin_attr); 277 } 278 279 static void w1_f0d_remove_slave(struct w1_slave *sl) 280 { 281 sysfs_remove_bin_file(&sl->dev.kobj, &w1_f0d_bin_attr); 282 } 283 284 static const struct w1_family_ops w1_f0d_fops = { 285 .add_slave = w1_f0d_add_slave, 286 .remove_slave = w1_f0d_remove_slave, 287 }; 288 289 static struct w1_family w1_family_0d = { 290 .fid = W1_EEPROM_DS2805, 291 .fops = &w1_f0d_fops, 292 }; 293 294 module_w1_family(w1_family_0d); 295 296 MODULE_LICENSE("GPL"); 297 MODULE_AUTHOR("Andrew Worsley amworsley@gmail.com"); 298 MODULE_DESCRIPTION("w1 family 0d driver for DS2805, 1kb EEPROM"); 299