1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * w1_ds2430.c - w1 family 14 (DS2430) driver 4 ** 5 * Copyright (c) 2019 Angelo Dureghello <angelo.dureghello@timesys.com> 6 * 7 * Cloned and modified from ds2431 8 * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net> 9 * 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/moduleparam.h> 15 #include <linux/device.h> 16 #include <linux/types.h> 17 #include <linux/delay.h> 18 19 #include <linux/w1.h> 20 21 #define W1_EEPROM_DS2430 0x14 22 23 #define W1_F14_EEPROM_SIZE 32 24 #define W1_F14_PAGE_COUNT 1 25 #define W1_F14_PAGE_BITS 5 26 #define W1_F14_PAGE_SIZE (1 << W1_F14_PAGE_BITS) 27 #define W1_F14_PAGE_MASK 0x1F 28 29 #define W1_F14_SCRATCH_BITS 5 30 #define W1_F14_SCRATCH_SIZE (1 << W1_F14_SCRATCH_BITS) 31 #define W1_F14_SCRATCH_MASK (W1_F14_SCRATCH_SIZE-1) 32 33 #define W1_F14_READ_EEPROM 0xF0 34 #define W1_F14_WRITE_SCRATCH 0x0F 35 #define W1_F14_READ_SCRATCH 0xAA 36 #define W1_F14_COPY_SCRATCH 0x55 37 #define W1_F14_VALIDATION_KEY 0xa5 38 39 #define W1_F14_TPROG_MS 11 40 #define W1_F14_READ_RETRIES 10 41 #define W1_F14_READ_MAXLEN W1_F14_SCRATCH_SIZE 42 43 /* 44 * Check the file size bounds and adjusts count as needed. 45 * This would not be needed if the file size didn't reset to 0 after a write. 46 */ 47 static inline size_t w1_f14_fix_count(loff_t off, size_t count, size_t size) 48 { 49 if (off > size) 50 return 0; 51 52 if ((off + count) > size) 53 return size - off; 54 55 return count; 56 } 57 58 /* 59 * Read a block from W1 ROM two times and compares the results. 60 * If they are equal they are returned, otherwise the read 61 * is repeated W1_F14_READ_RETRIES times. 62 * 63 * count must not exceed W1_F14_READ_MAXLEN. 64 */ 65 static int w1_f14_readblock(struct w1_slave *sl, int off, int count, char *buf) 66 { 67 u8 wrbuf[2]; 68 u8 cmp[W1_F14_READ_MAXLEN]; 69 int tries = W1_F14_READ_RETRIES; 70 71 do { 72 wrbuf[0] = W1_F14_READ_EEPROM; 73 wrbuf[1] = off & 0xff; 74 75 if (w1_reset_select_slave(sl)) 76 return -1; 77 78 w1_write_block(sl->master, wrbuf, 2); 79 w1_read_block(sl->master, buf, count); 80 81 if (w1_reset_select_slave(sl)) 82 return -1; 83 84 w1_write_block(sl->master, wrbuf, 2); 85 w1_read_block(sl->master, cmp, count); 86 87 if (!memcmp(cmp, buf, count)) 88 return 0; 89 } while (--tries); 90 91 dev_err(&sl->dev, "proof reading failed %d times\n", 92 W1_F14_READ_RETRIES); 93 94 return -1; 95 } 96 97 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, 98 struct bin_attribute *bin_attr, char *buf, 99 loff_t off, size_t count) 100 { 101 struct w1_slave *sl = kobj_to_w1_slave(kobj); 102 int todo = count; 103 104 count = w1_f14_fix_count(off, count, W1_F14_EEPROM_SIZE); 105 if (count == 0) 106 return 0; 107 108 mutex_lock(&sl->master->bus_mutex); 109 110 /* read directly from the EEPROM in chunks of W1_F14_READ_MAXLEN */ 111 while (todo > 0) { 112 int block_read; 113 114 if (todo >= W1_F14_READ_MAXLEN) 115 block_read = W1_F14_READ_MAXLEN; 116 else 117 block_read = todo; 118 119 if (w1_f14_readblock(sl, off, block_read, buf) < 0) 120 count = -EIO; 121 122 todo -= W1_F14_READ_MAXLEN; 123 buf += W1_F14_READ_MAXLEN; 124 off += W1_F14_READ_MAXLEN; 125 } 126 127 mutex_unlock(&sl->master->bus_mutex); 128 129 return count; 130 } 131 132 /* 133 * Writes to the scratchpad and reads it back for verification. 134 * Then copies the scratchpad to EEPROM. 135 * The data must be aligned at W1_F14_SCRATCH_SIZE bytes and 136 * must be W1_F14_SCRATCH_SIZE bytes long. 137 * The master must be locked. 138 * 139 * @param sl The slave structure 140 * @param addr Address for the write 141 * @param len length must be <= (W1_F14_PAGE_SIZE - (addr & W1_F14_PAGE_MASK)) 142 * @param data The data to write 143 * @return 0=Success -1=failure 144 */ 145 static int w1_f14_write(struct w1_slave *sl, int addr, int len, const u8 *data) 146 { 147 int tries = W1_F14_READ_RETRIES; 148 u8 wrbuf[2]; 149 u8 rdbuf[W1_F14_SCRATCH_SIZE + 3]; 150 151 retry: 152 153 /* Write the data to the scratchpad */ 154 if (w1_reset_select_slave(sl)) 155 return -1; 156 157 wrbuf[0] = W1_F14_WRITE_SCRATCH; 158 wrbuf[1] = addr & 0xff; 159 160 w1_write_block(sl->master, wrbuf, 2); 161 w1_write_block(sl->master, data, len); 162 163 /* Read the scratchpad and verify */ 164 if (w1_reset_select_slave(sl)) 165 return -1; 166 167 w1_write_8(sl->master, W1_F14_READ_SCRATCH); 168 w1_read_block(sl->master, rdbuf, len + 2); 169 170 /* 171 * Compare what was read against the data written 172 * Note: on read scratchpad, device returns 2 bulk 0xff bytes, 173 * to be discarded. 174 */ 175 if ((memcmp(data, &rdbuf[2], len) != 0)) { 176 177 if (--tries) 178 goto retry; 179 180 dev_err(&sl->dev, 181 "could not write to eeprom, scratchpad compare failed %d times\n", 182 W1_F14_READ_RETRIES); 183 184 return -1; 185 } 186 187 /* Copy the scratchpad to EEPROM */ 188 if (w1_reset_select_slave(sl)) 189 return -1; 190 191 wrbuf[0] = W1_F14_COPY_SCRATCH; 192 wrbuf[1] = W1_F14_VALIDATION_KEY; 193 w1_write_block(sl->master, wrbuf, 2); 194 195 /* Sleep for tprog ms to wait for the write to complete */ 196 msleep(W1_F14_TPROG_MS); 197 198 /* Reset the bus to wake up the EEPROM */ 199 w1_reset_bus(sl->master); 200 201 return 0; 202 } 203 204 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, 205 struct bin_attribute *bin_attr, char *buf, 206 loff_t off, size_t count) 207 { 208 struct w1_slave *sl = kobj_to_w1_slave(kobj); 209 int addr, len; 210 int copy; 211 212 count = w1_f14_fix_count(off, count, W1_F14_EEPROM_SIZE); 213 if (count == 0) 214 return 0; 215 216 mutex_lock(&sl->master->bus_mutex); 217 218 /* Can only write data in blocks of the size of the scratchpad */ 219 addr = off; 220 len = count; 221 while (len > 0) { 222 223 /* if len too short or addr not aligned */ 224 if (len < W1_F14_SCRATCH_SIZE || addr & W1_F14_SCRATCH_MASK) { 225 char tmp[W1_F14_SCRATCH_SIZE]; 226 227 /* read the block and update the parts to be written */ 228 if (w1_f14_readblock(sl, addr & ~W1_F14_SCRATCH_MASK, 229 W1_F14_SCRATCH_SIZE, tmp)) { 230 count = -EIO; 231 goto out_up; 232 } 233 234 /* copy at most to the boundary of the PAGE or len */ 235 copy = W1_F14_SCRATCH_SIZE - 236 (addr & W1_F14_SCRATCH_MASK); 237 238 if (copy > len) 239 copy = len; 240 241 memcpy(&tmp[addr & W1_F14_SCRATCH_MASK], buf, copy); 242 if (w1_f14_write(sl, addr & ~W1_F14_SCRATCH_MASK, 243 W1_F14_SCRATCH_SIZE, tmp) < 0) { 244 count = -EIO; 245 goto out_up; 246 } 247 } else { 248 249 copy = W1_F14_SCRATCH_SIZE; 250 if (w1_f14_write(sl, addr, copy, buf) < 0) { 251 count = -EIO; 252 goto out_up; 253 } 254 } 255 buf += copy; 256 addr += copy; 257 len -= copy; 258 } 259 260 out_up: 261 mutex_unlock(&sl->master->bus_mutex); 262 263 return count; 264 } 265 266 static BIN_ATTR_RW(eeprom, W1_F14_EEPROM_SIZE); 267 268 static struct bin_attribute *w1_f14_bin_attrs[] = { 269 &bin_attr_eeprom, 270 NULL, 271 }; 272 273 static const struct attribute_group w1_f14_group = { 274 .bin_attrs = w1_f14_bin_attrs, 275 }; 276 277 static const struct attribute_group *w1_f14_groups[] = { 278 &w1_f14_group, 279 NULL, 280 }; 281 282 static struct w1_family_ops w1_f14_fops = { 283 .groups = w1_f14_groups, 284 }; 285 286 static struct w1_family w1_family_14 = { 287 .fid = W1_EEPROM_DS2430, 288 .fops = &w1_f14_fops, 289 }; 290 module_w1_family(w1_family_14); 291 292 MODULE_AUTHOR("Angelo Dureghello <angelo.dureghello@timesys.com>"); 293 MODULE_DESCRIPTION("w1 family 14 driver for DS2430, 256b EEPROM"); 294 MODULE_LICENSE("GPL"); 295 MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2430)); 296