1 /* 2 * w1_ds2433.c - w1 family 23 (DS2433) driver 3 * 4 * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com> 5 * 6 * This source code is licensed under the GNU General Public License, 7 * Version 2. See the file COPYING for more details. 8 */ 9 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 #include <linux/slab.h> 17 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 18 #include <linux/crc16.h> 19 20 #define CRC16_INIT 0 21 #define CRC16_VALID 0xb001 22 23 #endif 24 25 #include <linux/w1.h> 26 27 #define W1_EEPROM_DS2433 0x23 28 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 34 35 #define W1_F23_TIME 300 36 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 41 42 struct w1_f23_data { 43 u8 memory[W1_EEPROM_SIZE]; 44 u32 validcrc; 45 }; 46 47 /** 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. 50 */ 51 static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size) 52 { 53 if (off > size) 54 return 0; 55 56 if ((off + count) > size) 57 return (size - off); 58 59 return count; 60 } 61 62 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 63 static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data, 64 int block) 65 { 66 u8 wrbuf[3]; 67 int off = block * W1_PAGE_SIZE; 68 69 if (data->validcrc & (1 << block)) 70 return 0; 71 72 if (w1_reset_select_slave(sl)) { 73 data->validcrc = 0; 74 return -EIO; 75 } 76 77 wrbuf[0] = W1_F23_READ_EEPROM; 78 wrbuf[1] = off & 0xff; 79 wrbuf[2] = off >> 8; 80 w1_write_block(sl->master, wrbuf, 3); 81 w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE); 82 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); 86 87 return 0; 88 } 89 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */ 90 91 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, 92 struct bin_attribute *bin_attr, char *buf, 93 loff_t off, size_t count) 94 { 95 struct w1_slave *sl = kobj_to_w1_slave(kobj); 96 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 97 struct w1_f23_data *data = sl->family_data; 98 int i, min_page, max_page; 99 #else 100 u8 wrbuf[3]; 101 #endif 102 103 if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0) 104 return 0; 105 106 mutex_lock(&sl->master->bus_mutex); 107 108 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 109 110 min_page = (off >> W1_PAGE_BITS); 111 max_page = (off + count - 1) >> W1_PAGE_BITS; 112 for (i = min_page; i <= max_page; i++) { 113 if (w1_f23_refresh_block(sl, data, i)) { 114 count = -EIO; 115 goto out_up; 116 } 117 } 118 memcpy(buf, &data->memory[off], count); 119 120 #else /* CONFIG_W1_SLAVE_DS2433_CRC */ 121 122 /* read directly from the EEPROM */ 123 if (w1_reset_select_slave(sl)) { 124 count = -EIO; 125 goto out_up; 126 } 127 128 wrbuf[0] = W1_F23_READ_EEPROM; 129 wrbuf[1] = off & 0xff; 130 wrbuf[2] = off >> 8; 131 w1_write_block(sl->master, wrbuf, 3); 132 w1_read_block(sl->master, buf, count); 133 134 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */ 135 136 out_up: 137 mutex_unlock(&sl->master->bus_mutex); 138 139 return count; 140 } 141 142 /** 143 * Writes to the scratchpad and reads it back for verification. 144 * Then copies the scratchpad to EEPROM. 145 * The data must be on one page. 146 * The master must be locked. 147 * 148 * @param sl The slave structure 149 * @param addr Address for the write 150 * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) 151 * @param data The data to write 152 * @return 0=Success -1=failure 153 */ 154 static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data) 155 { 156 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 157 struct w1_f23_data *f23 = sl->family_data; 158 #endif 159 u8 wrbuf[4]; 160 u8 rdbuf[W1_PAGE_SIZE + 3]; 161 u8 es = (addr + len - 1) & 0x1f; 162 163 /* Write the data to the scratchpad */ 164 if (w1_reset_select_slave(sl)) 165 return -1; 166 167 wrbuf[0] = W1_F23_WRITE_SCRATCH; 168 wrbuf[1] = addr & 0xff; 169 wrbuf[2] = addr >> 8; 170 171 w1_write_block(sl->master, wrbuf, 3); 172 w1_write_block(sl->master, data, len); 173 174 /* Read the scratchpad and verify */ 175 if (w1_reset_select_slave(sl)) 176 return -1; 177 178 w1_write_8(sl->master, W1_F23_READ_SCRATCH); 179 w1_read_block(sl->master, rdbuf, len + 3); 180 181 /* Compare what was read against the data written */ 182 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || 183 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) 184 return -1; 185 186 /* Copy the scratchpad to EEPROM */ 187 if (w1_reset_select_slave(sl)) 188 return -1; 189 190 wrbuf[0] = W1_F23_COPY_SCRATCH; 191 wrbuf[3] = es; 192 w1_write_block(sl->master, wrbuf, 4); 193 194 /* Sleep for 5 ms to wait for the write to complete */ 195 msleep(5); 196 197 /* Reset the bus to wake up the EEPROM (this may not be needed) */ 198 w1_reset_bus(sl->master); 199 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 200 f23->validcrc &= ~(1 << (addr >> W1_PAGE_BITS)); 201 #endif 202 return 0; 203 } 204 205 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, 206 struct bin_attribute *bin_attr, char *buf, 207 loff_t off, size_t count) 208 { 209 struct w1_slave *sl = kobj_to_w1_slave(kobj); 210 int addr, len, idx; 211 212 if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0) 213 return 0; 214 215 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 216 /* can only write full blocks in cached mode */ 217 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) { 218 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n", 219 (int)off, count); 220 return -EINVAL; 221 } 222 223 /* make sure the block CRCs are valid */ 224 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) { 225 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) { 226 dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off); 227 return -EINVAL; 228 } 229 } 230 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */ 231 232 mutex_lock(&sl->master->bus_mutex); 233 234 /* Can only write data to one page at a time */ 235 idx = 0; 236 while (idx < count) { 237 addr = off + idx; 238 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK); 239 if (len > (count - idx)) 240 len = count - idx; 241 242 if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) { 243 count = -EIO; 244 goto out_up; 245 } 246 idx += len; 247 } 248 249 out_up: 250 mutex_unlock(&sl->master->bus_mutex); 251 252 return count; 253 } 254 255 static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE); 256 257 static struct bin_attribute *w1_f23_bin_attributes[] = { 258 &bin_attr_eeprom, 259 NULL, 260 }; 261 262 static const struct attribute_group w1_f23_group = { 263 .bin_attrs = w1_f23_bin_attributes, 264 }; 265 266 static const struct attribute_group *w1_f23_groups[] = { 267 &w1_f23_group, 268 NULL, 269 }; 270 271 static int w1_f23_add_slave(struct w1_slave *sl) 272 { 273 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 274 struct w1_f23_data *data; 275 276 data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL); 277 if (!data) 278 return -ENOMEM; 279 sl->family_data = data; 280 281 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */ 282 return 0; 283 } 284 285 static void w1_f23_remove_slave(struct w1_slave *sl) 286 { 287 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 288 kfree(sl->family_data); 289 sl->family_data = NULL; 290 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */ 291 } 292 293 static struct w1_family_ops w1_f23_fops = { 294 .add_slave = w1_f23_add_slave, 295 .remove_slave = w1_f23_remove_slave, 296 .groups = w1_f23_groups, 297 }; 298 299 static struct w1_family w1_family_23 = { 300 .fid = W1_EEPROM_DS2433, 301 .fops = &w1_f23_fops, 302 }; 303 module_w1_family(w1_family_23); 304 305 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>"); 306 MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM"); 307 MODULE_LICENSE("GPL"); 308 MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433)); 309