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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 | /* * 1-Wire implementation for the ds2438 chip * * Copyright (c) 2017 Mariusz Bialonczyk <manio@skyboo.net> * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/device.h> #include <linux/types.h> #include <linux/delay.h> #include <linux/w1.h> #define W1_FAMILY_DS2438 0x26 #define W1_DS2438_RETRIES 3 /* Memory commands */ #define W1_DS2438_READ_SCRATCH 0xBE #define W1_DS2438_WRITE_SCRATCH 0x4E #define W1_DS2438_COPY_SCRATCH 0x48 #define W1_DS2438_RECALL_MEMORY 0xB8 /* Register commands */ #define W1_DS2438_CONVERT_TEMP 0x44 #define W1_DS2438_CONVERT_VOLTAGE 0xB4 #define DS2438_PAGE_SIZE 8 #define DS2438_ADC_INPUT_VAD 0 #define DS2438_ADC_INPUT_VDD 1 #define DS2438_MAX_CONVERSION_TIME 10 /* ms */ /* Page #0 definitions */ #define DS2438_STATUS_REG 0x00 /* Status/Configuration Register */ #define DS2438_STATUS_IAD (1 << 0) /* Current A/D Control Bit */ #define DS2438_STATUS_CA (1 << 1) /* Current Accumulator Configuration */ #define DS2438_STATUS_EE (1 << 2) /* Current Accumulator Shadow Selector bit */ #define DS2438_STATUS_AD (1 << 3) /* Voltage A/D Input Select Bit */ #define DS2438_STATUS_TB (1 << 4) /* Temperature Busy Flag */ #define DS2438_STATUS_NVB (1 << 5) /* Nonvolatile Memory Busy Flag */ #define DS2438_STATUS_ADB (1 << 6) /* A/D Converter Busy Flag */ #define DS2438_TEMP_LSB 0x01 #define DS2438_TEMP_MSB 0x02 #define DS2438_VOLTAGE_LSB 0x03 #define DS2438_VOLTAGE_MSB 0x04 #define DS2438_CURRENT_LSB 0x05 #define DS2438_CURRENT_MSB 0x06 #define DS2438_THRESHOLD 0x07 static int w1_ds2438_get_page(struct w1_slave *sl, int pageno, u8 *buf) { unsigned int retries = W1_DS2438_RETRIES; u8 w1_buf[2]; u8 crc; size_t count; while (retries--) { crc = 0; if (w1_reset_select_slave(sl)) continue; w1_buf[0] = W1_DS2438_RECALL_MEMORY; w1_buf[1] = 0x00; w1_write_block(sl->master, w1_buf, 2); if (w1_reset_select_slave(sl)) continue; w1_buf[0] = W1_DS2438_READ_SCRATCH; w1_buf[1] = 0x00; w1_write_block(sl->master, w1_buf, 2); count = w1_read_block(sl->master, buf, DS2438_PAGE_SIZE + 1); if (count == DS2438_PAGE_SIZE + 1) { crc = w1_calc_crc8(buf, DS2438_PAGE_SIZE); /* check for correct CRC */ if ((u8)buf[DS2438_PAGE_SIZE] == crc) return 0; } } return -1; } static int w1_ds2438_get_temperature(struct w1_slave *sl, int16_t *temperature) { unsigned int retries = W1_DS2438_RETRIES; u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/]; unsigned int tm = DS2438_MAX_CONVERSION_TIME; unsigned long sleep_rem; int ret; mutex_lock(&sl->master->bus_mutex); while (retries--) { if (w1_reset_select_slave(sl)) continue; w1_write_8(sl->master, W1_DS2438_CONVERT_TEMP); mutex_unlock(&sl->master->bus_mutex); sleep_rem = msleep_interruptible(tm); if (sleep_rem != 0) { ret = -1; goto post_unlock; } if (mutex_lock_interruptible(&sl->master->bus_mutex) != 0) { ret = -1; goto post_unlock; } break; } if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) { *temperature = (((int16_t) w1_buf[DS2438_TEMP_MSB]) << 8) | ((uint16_t) w1_buf[DS2438_TEMP_LSB]); ret = 0; } else ret = -1; mutex_unlock(&sl->master->bus_mutex); post_unlock: return ret; } static int w1_ds2438_change_config_bit(struct w1_slave *sl, u8 mask, u8 value) { unsigned int retries = W1_DS2438_RETRIES; u8 w1_buf[3]; u8 status; int perform_write = 0; while (retries--) { if (w1_reset_select_slave(sl)) continue; w1_buf[0] = W1_DS2438_RECALL_MEMORY; w1_buf[1] = 0x00; w1_write_block(sl->master, w1_buf, 2); if (w1_reset_select_slave(sl)) continue; w1_buf[0] = W1_DS2438_READ_SCRATCH; w1_buf[1] = 0x00; w1_write_block(sl->master, w1_buf, 2); /* reading one byte of result */ status = w1_read_8(sl->master); /* if bit0=1, set a value to a mask for easy compare */ if (value) value = mask; if ((status & mask) == value) return 0; /* already set as requested */ else { /* changing bit */ status ^= mask; perform_write = 1; } break; } if (perform_write) { retries = W1_DS2438_RETRIES; while (retries--) { if (w1_reset_select_slave(sl)) continue; w1_buf[0] = W1_DS2438_WRITE_SCRATCH; w1_buf[1] = 0x00; w1_buf[2] = status; w1_write_block(sl->master, w1_buf, 3); if (w1_reset_select_slave(sl)) continue; w1_buf[0] = W1_DS2438_COPY_SCRATCH; w1_buf[1] = 0x00; w1_write_block(sl->master, w1_buf, 2); return 0; } } return -1; } static uint16_t w1_ds2438_get_voltage(struct w1_slave *sl, int adc_input, uint16_t *voltage) { unsigned int retries = W1_DS2438_RETRIES; u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/]; unsigned int tm = DS2438_MAX_CONVERSION_TIME; unsigned long sleep_rem; int ret; mutex_lock(&sl->master->bus_mutex); if (w1_ds2438_change_config_bit(sl, DS2438_STATUS_AD, adc_input)) { ret = -1; goto pre_unlock; } while (retries--) { if (w1_reset_select_slave(sl)) continue; w1_write_8(sl->master, W1_DS2438_CONVERT_VOLTAGE); mutex_unlock(&sl->master->bus_mutex); sleep_rem = msleep_interruptible(tm); if (sleep_rem != 0) { ret = -1; goto post_unlock; } if (mutex_lock_interruptible(&sl->master->bus_mutex) != 0) { ret = -1; goto post_unlock; } break; } if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) { *voltage = (((uint16_t) w1_buf[DS2438_VOLTAGE_MSB]) << 8) | ((uint16_t) w1_buf[DS2438_VOLTAGE_LSB]); ret = 0; } else ret = -1; pre_unlock: mutex_unlock(&sl->master->bus_mutex); post_unlock: return ret; } static ssize_t iad_write(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count) { struct w1_slave *sl = kobj_to_w1_slave(kobj); int ret; if (count != 1 || off != 0) return -EFAULT; mutex_lock(&sl->master->bus_mutex); if (w1_ds2438_change_config_bit(sl, DS2438_STATUS_IAD, *buf & 0x01) == 0) ret = 1; else ret = -EIO; mutex_unlock(&sl->master->bus_mutex); return ret; } static ssize_t page0_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count) { struct w1_slave *sl = kobj_to_w1_slave(kobj); int ret; u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/]; if (off != 0) return 0; if (!buf) return -EINVAL; mutex_lock(&sl->master->bus_mutex); if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) { memcpy(buf, &w1_buf, DS2438_PAGE_SIZE); ret = DS2438_PAGE_SIZE; } else ret = -EIO; mutex_unlock(&sl->master->bus_mutex); return ret; } static ssize_t temperature_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count) { struct w1_slave *sl = kobj_to_w1_slave(kobj); int ret; ssize_t c = PAGE_SIZE; int16_t temp; if (off != 0) return 0; if (!buf) return -EINVAL; if (w1_ds2438_get_temperature(sl, &temp) == 0) { c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", temp); ret = PAGE_SIZE - c; } else ret = -EIO; return ret; } static ssize_t vad_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count) { struct w1_slave *sl = kobj_to_w1_slave(kobj); int ret; ssize_t c = PAGE_SIZE; uint16_t voltage; if (off != 0) return 0; if (!buf) return -EINVAL; if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VAD, &voltage) == 0) { c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage); ret = PAGE_SIZE - c; } else ret = -EIO; return ret; } static ssize_t vdd_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count) { struct w1_slave *sl = kobj_to_w1_slave(kobj); int ret; ssize_t c = PAGE_SIZE; uint16_t voltage; if (off != 0) return 0; if (!buf) return -EINVAL; if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VDD, &voltage) == 0) { c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage); ret = PAGE_SIZE - c; } else ret = -EIO; return ret; } static BIN_ATTR(iad, S_IRUGO | S_IWUSR | S_IWGRP, NULL, iad_write, 1); static BIN_ATTR_RO(page0, DS2438_PAGE_SIZE); static BIN_ATTR_RO(temperature, 0/* real length varies */); static BIN_ATTR_RO(vad, 0/* real length varies */); static BIN_ATTR_RO(vdd, 0/* real length varies */); static struct bin_attribute *w1_ds2438_bin_attrs[] = { &bin_attr_iad, &bin_attr_page0, &bin_attr_temperature, &bin_attr_vad, &bin_attr_vdd, NULL, }; static const struct attribute_group w1_ds2438_group = { .bin_attrs = w1_ds2438_bin_attrs, }; static const struct attribute_group *w1_ds2438_groups[] = { &w1_ds2438_group, NULL, }; static struct w1_family_ops w1_ds2438_fops = { .groups = w1_ds2438_groups, }; static struct w1_family w1_ds2438_family = { .fid = W1_FAMILY_DS2438, .fops = &w1_ds2438_fops, }; module_w1_family(w1_ds2438_family); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>"); MODULE_DESCRIPTION("1-wire driver for Maxim/Dallas DS2438 Smart Battery Monitor"); MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2438)); |