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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * w1_ds2805 - w1 family 0d (DS28E05) driver4 *5 * Copyright (c) 2016 Andrew Worsley amworsley@gmail.com6 */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 0x0D18 19#define W1_F0D_EEPROM_SIZE 12820#define W1_F0D_PAGE_BITS 321#define W1_F0D_PAGE_SIZE (1<<W1_F0D_PAGE_BITS)22#define W1_F0D_PAGE_MASK 0x0F23 24#define W1_F0D_SCRATCH_BITS 125#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 0xF029#define W1_F0D_WRITE_EEPROM 0x5530#define W1_F0D_RELEASE 0xFF31 32#define W1_F0D_CS_OK 0xAA /* Chip Status Ok */33 34#define W1_F0D_TPROG_MS 1635 36#define W1_F0D_READ_RETRIES 1037#define W1_F0D_READ_MAXLEN W1_F0D_EEPROM_SIZE38 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 */43static 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 read57 * is repeated W1_F0D_READ_RETRIES times.58 *59 * count must not exceed W1_F0D_READ_MAXLEN.60 */61static 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 94static 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 else114 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 and135 * must be W1_F0D_SCRATCH_SIZE bytes long.136 * The master must be locked.137 *138 * @param sl The slave structure139 * @param addr Address for the write140 * @param len length must be <= (W1_F0D_PAGE_SIZE - (addr & W1_F0D_PAGE_MASK))141 * @param data The data to write142 * @return 0=Success -1=failure143 */144static 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 157retry: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 202static 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 258out_up:259 mutex_unlock(&sl->master->mutex);260 261 return count;262}263 264static struct bin_attribute w1_f0d_bin_attr = {265 .attr = {266 .name = "eeprom",267 .mode = 0644,268 },269 .size = W1_F0D_EEPROM_SIZE,270 .read = w1_f0d_read_bin,271 .write = w1_f0d_write_bin,272};273 274static 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 279static void w1_f0d_remove_slave(struct w1_slave *sl)280{281 sysfs_remove_bin_file(&sl->dev.kobj, &w1_f0d_bin_attr);282}283 284static const struct w1_family_ops w1_f0d_fops = {285 .add_slave = w1_f0d_add_slave,286 .remove_slave = w1_f0d_remove_slave,287};288 289static struct w1_family w1_family_0d = {290 .fid = W1_EEPROM_DS2805,291 .fops = &w1_f0d_fops,292};293 294module_w1_family(w1_family_0d);295 296MODULE_LICENSE("GPL");297MODULE_AUTHOR("Andrew Worsley amworsley@gmail.com");298MODULE_DESCRIPTION("w1 family 0d driver for DS2805, 1kb EEPROM");299