1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * An I2C driver for the Intersil ISL 12022 4 * 5 * Author: Roman Fietze <roman.fietze@telemotive.de> 6 * 7 * Based on the Philips PCF8563 RTC 8 * by Alessandro Zummo <a.zummo@towertech.it>. 9 */ 10 11 #include <linux/bcd.h> 12 #include <linux/bitfield.h> 13 #include <linux/clk-provider.h> 14 #include <linux/err.h> 15 #include <linux/hwmon.h> 16 #include <linux/i2c.h> 17 #include <linux/module.h> 18 #include <linux/regmap.h> 19 #include <linux/rtc.h> 20 #include <linux/slab.h> 21 22 #include <asm/byteorder.h> 23 24 /* ISL register offsets */ 25 #define ISL12022_REG_SC 0x00 26 #define ISL12022_REG_MN 0x01 27 #define ISL12022_REG_HR 0x02 28 #define ISL12022_REG_DT 0x03 29 #define ISL12022_REG_MO 0x04 30 #define ISL12022_REG_YR 0x05 31 #define ISL12022_REG_DW 0x06 32 33 #define ISL12022_REG_SR 0x07 34 #define ISL12022_REG_INT 0x08 35 36 #define ISL12022_REG_PWR_VBAT 0x0a 37 38 #define ISL12022_REG_BETA 0x0d 39 #define ISL12022_REG_TEMP_L 0x28 40 41 /* ISL register bits */ 42 #define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */ 43 44 #define ISL12022_SR_LBAT85 (1 << 2) 45 #define ISL12022_SR_LBAT75 (1 << 1) 46 47 #define ISL12022_INT_WRTC (1 << 6) 48 #define ISL12022_INT_FO_MASK GENMASK(3, 0) 49 #define ISL12022_INT_FO_OFF 0x0 50 #define ISL12022_INT_FO_32K 0x1 51 52 #define ISL12022_REG_VB85_MASK GENMASK(5, 3) 53 #define ISL12022_REG_VB75_MASK GENMASK(2, 0) 54 55 #define ISL12022_BETA_TSE (1 << 7) 56 57 static umode_t isl12022_hwmon_is_visible(const void *data, 58 enum hwmon_sensor_types type, 59 u32 attr, int channel) 60 { 61 if (type == hwmon_temp && attr == hwmon_temp_input) 62 return 0444; 63 64 return 0; 65 } 66 67 /* 68 * A user-initiated temperature conversion is not started by this function, 69 * so the temperature is updated once every ~60 seconds. 70 */ 71 static int isl12022_hwmon_read_temp(struct device *dev, long *mC) 72 { 73 struct regmap *regmap = dev_get_drvdata(dev); 74 int temp, ret; 75 __le16 buf; 76 77 ret = regmap_bulk_read(regmap, ISL12022_REG_TEMP_L, &buf, sizeof(buf)); 78 if (ret) 79 return ret; 80 /* 81 * Temperature is represented as a 10-bit number, unit half-Kelvins. 82 */ 83 temp = le16_to_cpu(buf); 84 temp *= 500; 85 temp -= 273000; 86 87 *mC = temp; 88 89 return 0; 90 } 91 92 static int isl12022_hwmon_read(struct device *dev, 93 enum hwmon_sensor_types type, 94 u32 attr, int channel, long *val) 95 { 96 if (type == hwmon_temp && attr == hwmon_temp_input) 97 return isl12022_hwmon_read_temp(dev, val); 98 99 return -EOPNOTSUPP; 100 } 101 102 static const struct hwmon_channel_info * const isl12022_hwmon_info[] = { 103 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT), 104 NULL 105 }; 106 107 static const struct hwmon_ops isl12022_hwmon_ops = { 108 .is_visible = isl12022_hwmon_is_visible, 109 .read = isl12022_hwmon_read, 110 }; 111 112 static const struct hwmon_chip_info isl12022_hwmon_chip_info = { 113 .ops = &isl12022_hwmon_ops, 114 .info = isl12022_hwmon_info, 115 }; 116 117 static void isl12022_hwmon_register(struct device *dev) 118 { 119 struct regmap *regmap = dev_get_drvdata(dev); 120 struct device *hwmon; 121 int ret; 122 123 if (!IS_REACHABLE(CONFIG_HWMON)) 124 return; 125 126 ret = regmap_update_bits(regmap, ISL12022_REG_BETA, 127 ISL12022_BETA_TSE, ISL12022_BETA_TSE); 128 if (ret) { 129 dev_warn(dev, "unable to enable temperature sensor\n"); 130 return; 131 } 132 133 hwmon = devm_hwmon_device_register_with_info(dev, "isl12022", regmap, 134 &isl12022_hwmon_chip_info, 135 NULL); 136 if (IS_ERR(hwmon)) 137 dev_warn(dev, "unable to register hwmon device: %pe\n", hwmon); 138 } 139 140 /* 141 * In the routines that deal directly with the isl12022 hardware, we use 142 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 143 */ 144 static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm) 145 { 146 struct regmap *regmap = dev_get_drvdata(dev); 147 uint8_t buf[ISL12022_REG_INT + 1]; 148 int ret; 149 150 ret = regmap_bulk_read(regmap, ISL12022_REG_SC, buf, sizeof(buf)); 151 if (ret) 152 return ret; 153 154 dev_dbg(dev, 155 "raw data is sec=%02x, min=%02x, hr=%02x, mday=%02x, mon=%02x, year=%02x, wday=%02x, sr=%02x, int=%02x", 156 buf[ISL12022_REG_SC], 157 buf[ISL12022_REG_MN], 158 buf[ISL12022_REG_HR], 159 buf[ISL12022_REG_DT], 160 buf[ISL12022_REG_MO], 161 buf[ISL12022_REG_YR], 162 buf[ISL12022_REG_DW], 163 buf[ISL12022_REG_SR], 164 buf[ISL12022_REG_INT]); 165 166 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F); 167 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F); 168 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F); 169 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F); 170 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07; 171 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1; 172 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100; 173 174 dev_dbg(dev, "%s: %ptR\n", __func__, tm); 175 176 return 0; 177 } 178 179 static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm) 180 { 181 struct regmap *regmap = dev_get_drvdata(dev); 182 int ret; 183 uint8_t buf[ISL12022_REG_DW + 1]; 184 185 dev_dbg(dev, "%s: %ptR\n", __func__, tm); 186 187 /* Ensure the write enable bit is set. */ 188 ret = regmap_update_bits(regmap, ISL12022_REG_INT, 189 ISL12022_INT_WRTC, ISL12022_INT_WRTC); 190 if (ret) 191 return ret; 192 193 /* hours, minutes and seconds */ 194 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec); 195 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min); 196 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL; 197 198 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday); 199 200 /* month, 1 - 12 */ 201 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1); 202 203 /* year and century */ 204 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100); 205 206 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07; 207 208 return regmap_bulk_write(regmap, ISL12022_REG_SC, buf, sizeof(buf)); 209 } 210 211 static int isl12022_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 212 { 213 struct regmap *regmap = dev_get_drvdata(dev); 214 u32 user, val; 215 int ret; 216 217 switch (cmd) { 218 case RTC_VL_READ: 219 ret = regmap_read(regmap, ISL12022_REG_SR, &val); 220 if (ret) 221 return ret; 222 223 user = 0; 224 if (val & ISL12022_SR_LBAT85) 225 user |= RTC_VL_BACKUP_LOW; 226 227 if (val & ISL12022_SR_LBAT75) 228 user |= RTC_VL_BACKUP_EMPTY; 229 230 return put_user(user, (u32 __user *)arg); 231 232 default: 233 return -ENOIOCTLCMD; 234 } 235 } 236 237 static const struct rtc_class_ops isl12022_rtc_ops = { 238 .ioctl = isl12022_rtc_ioctl, 239 .read_time = isl12022_rtc_read_time, 240 .set_time = isl12022_rtc_set_time, 241 }; 242 243 static const struct regmap_config regmap_config = { 244 .reg_bits = 8, 245 .val_bits = 8, 246 .use_single_write = true, 247 }; 248 249 static int isl12022_register_clock(struct device *dev) 250 { 251 struct regmap *regmap = dev_get_drvdata(dev); 252 struct clk_hw *hw; 253 int ret; 254 255 if (!device_property_present(dev, "#clock-cells")) { 256 /* 257 * Disabling the F_OUT pin reduces the power 258 * consumption in battery mode by ~25%. 259 */ 260 regmap_update_bits(regmap, ISL12022_REG_INT, ISL12022_INT_FO_MASK, 261 ISL12022_INT_FO_OFF); 262 263 return 0; 264 } 265 266 if (!IS_ENABLED(CONFIG_COMMON_CLK)) 267 return 0; 268 269 /* 270 * For now, only support a fixed clock of 32768Hz (the reset default). 271 */ 272 ret = regmap_update_bits(regmap, ISL12022_REG_INT, 273 ISL12022_INT_FO_MASK, ISL12022_INT_FO_32K); 274 if (ret) 275 return ret; 276 277 hw = devm_clk_hw_register_fixed_rate(dev, "isl12022", NULL, 0, 32768); 278 if (IS_ERR(hw)) 279 return PTR_ERR(hw); 280 281 return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, hw); 282 } 283 284 static const u32 trip_levels[2][7] = { 285 { 2125000, 2295000, 2550000, 2805000, 3060000, 4250000, 4675000 }, 286 { 1875000, 2025000, 2250000, 2475000, 2700000, 3750000, 4125000 }, 287 }; 288 289 static void isl12022_set_trip_levels(struct device *dev) 290 { 291 struct regmap *regmap = dev_get_drvdata(dev); 292 u32 levels[2] = {0, 0}; 293 int ret, i, j, x[2]; 294 u8 val, mask; 295 296 device_property_read_u32_array(dev, "isil,battery-trip-levels-microvolt", 297 levels, 2); 298 299 for (i = 0; i < 2; i++) { 300 for (j = 0; j < ARRAY_SIZE(trip_levels[i]) - 1; j++) { 301 if (levels[i] <= trip_levels[i][j]) 302 break; 303 } 304 x[i] = j; 305 } 306 307 val = FIELD_PREP(ISL12022_REG_VB85_MASK, x[0]) | 308 FIELD_PREP(ISL12022_REG_VB75_MASK, x[1]); 309 mask = ISL12022_REG_VB85_MASK | ISL12022_REG_VB75_MASK; 310 311 ret = regmap_update_bits(regmap, ISL12022_REG_PWR_VBAT, mask, val); 312 if (ret) 313 dev_warn(dev, "unable to set battery alarm levels: %d\n", ret); 314 315 /* 316 * Force a write of the TSE bit in the BETA register, in order 317 * to trigger an update of the LBAT75 and LBAT85 bits in the 318 * status register. In battery backup mode, those bits have 319 * another meaning, so without this, they may contain stale 320 * values for up to a minute after power-on. 321 */ 322 regmap_write_bits(regmap, ISL12022_REG_BETA, 323 ISL12022_BETA_TSE, ISL12022_BETA_TSE); 324 } 325 326 static int isl12022_probe(struct i2c_client *client) 327 { 328 struct rtc_device *rtc; 329 struct regmap *regmap; 330 int ret; 331 332 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 333 return -ENODEV; 334 335 regmap = devm_regmap_init_i2c(client, ®map_config); 336 if (IS_ERR(regmap)) { 337 dev_err(&client->dev, "regmap allocation failed\n"); 338 return PTR_ERR(regmap); 339 } 340 341 dev_set_drvdata(&client->dev, regmap); 342 343 ret = isl12022_register_clock(&client->dev); 344 if (ret) 345 return ret; 346 347 isl12022_set_trip_levels(&client->dev); 348 isl12022_hwmon_register(&client->dev); 349 350 rtc = devm_rtc_allocate_device(&client->dev); 351 if (IS_ERR(rtc)) 352 return PTR_ERR(rtc); 353 354 rtc->ops = &isl12022_rtc_ops; 355 rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; 356 rtc->range_max = RTC_TIMESTAMP_END_2099; 357 358 return devm_rtc_register_device(rtc); 359 } 360 361 static const struct of_device_id isl12022_dt_match[] = { 362 { .compatible = "isl,isl12022" }, /* for backward compat., don't use */ 363 { .compatible = "isil,isl12022" }, 364 { }, 365 }; 366 MODULE_DEVICE_TABLE(of, isl12022_dt_match); 367 368 static const struct i2c_device_id isl12022_id[] = { 369 { "isl12022" }, 370 { } 371 }; 372 MODULE_DEVICE_TABLE(i2c, isl12022_id); 373 374 static struct i2c_driver isl12022_driver = { 375 .driver = { 376 .name = "rtc-isl12022", 377 .of_match_table = isl12022_dt_match, 378 }, 379 .probe = isl12022_probe, 380 .id_table = isl12022_id, 381 }; 382 383 module_i2c_driver(isl12022_driver); 384 385 MODULE_AUTHOR("roman.fietze@telemotive.de"); 386 MODULE_DESCRIPTION("ISL 12022 RTC driver"); 387 MODULE_LICENSE("GPL"); 388