drivers/rtc/rtc-isl12022.c

   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/i2c.h>
  12 #include <linux/bcd.h>
  13 #include <linux/rtc.h>
  14 #include <linux/slab.h>
  15 #include <linux/module.h>
  16 #include <linux/err.h>
  17 #include <linux/of.h>
  18 #include <linux/of_device.h>
  19 #include <linux/regmap.h>
  20 #include <linux/hwmon.h>
  21
  22 /* ISL register offsets */
  23 #define ISL12022_REG_SC         0x00
  24 #define ISL12022_REG_MN         0x01
  25 #define ISL12022_REG_HR         0x02
  26 #define ISL12022_REG_DT         0x03
  27 #define ISL12022_REG_MO         0x04
  28 #define ISL12022_REG_YR         0x05
  29 #define ISL12022_REG_DW         0x06
  30
  31 #define ISL12022_REG_SR         0x07
  32 #define ISL12022_REG_INT        0x08
  33
  34 #define ISL12022_REG_BETA       0x0d
  35 #define ISL12022_REG_TEMP_L     0x28
  36
  37 /* ISL register bits */
  38 #define ISL12022_HR_MIL         (1 << 7)        /* military or 24 hour time */
  39
  40 #define ISL12022_SR_LBAT85      (1 << 2)
  41 #define ISL12022_SR_LBAT75      (1 << 1)
  42
  43 #define ISL12022_INT_WRTC       (1 << 6)
  44
  45 #define ISL12022_BETA_TSE       (1 << 7)
  46
  47 static struct i2c_driver isl12022_driver;
  48
  49 struct isl12022 {
  50         struct rtc_device *rtc;
  51         struct regmap *regmap;
  52 };
  53
  54 static umode_t isl12022_hwmon_is_visible(const void *data,
  55                                          enum hwmon_sensor_types type,
  56                                          u32 attr, int channel)
  57 {
  58         if (type == hwmon_temp && attr == hwmon_temp_input)
  59                 return 0444;
  60
  61         return 0;
  62 }
  63
  64 /*
  65  * A user-initiated temperature conversion is not started by this function,
  66  * so the temperature is updated once every ~60 seconds.
  67  */
  68 static int isl12022_hwmon_read_temp(struct device *dev, long *mC)
  69 {
  70         struct isl12022 *isl12022 = dev_get_drvdata(dev);
  71         struct regmap *regmap = isl12022->regmap;
  72         u8 temp_buf[2];
  73         int temp, ret;
  74
  75         ret = regmap_bulk_read(regmap, ISL12022_REG_TEMP_L,
  76                                temp_buf, sizeof(temp_buf));
  77         if (ret)
  78                 return ret;
  79         /*
  80          * Temperature is represented as a 10-bit number, unit half-Kelvins.
  81          */
  82         temp = (temp_buf[1] << 8) | temp_buf[0];
  83         temp *= 500;
  84         temp -= 273000;
  85
  86         *mC = temp;
  87
  88         return 0;
  89 }
  90
  91 static int isl12022_hwmon_read(struct device *dev,
  92                                enum hwmon_sensor_types type,
  93                                u32 attr, int channel, long *val)
  94 {
  95         if (type == hwmon_temp && attr == hwmon_temp_input)
  96                 return isl12022_hwmon_read_temp(dev, val);
  97
  98         return -EOPNOTSUPP;
  99 }
 100
 101 static const struct hwmon_channel_info *isl12022_hwmon_info[] = {
 102         HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
 103         NULL
 104 };
 105
 106 static const struct hwmon_ops isl12022_hwmon_ops = {
 107         .is_visible = isl12022_hwmon_is_visible,
 108         .read = isl12022_hwmon_read,
 109 };
 110
 111 static const struct hwmon_chip_info isl12022_hwmon_chip_info = {
 112         .ops = &isl12022_hwmon_ops,
 113         .info = isl12022_hwmon_info,
 114 };
 115
 116 static void isl12022_hwmon_register(struct device *dev)
 117 {
 118         struct isl12022 *isl12022;
 119         struct device *hwmon;
 120         int ret;
 121
 122         if (!IS_REACHABLE(CONFIG_HWMON))
 123                 return;
 124
 125         isl12022 = dev_get_drvdata(dev);
 126
 127         ret = regmap_update_bits(isl12022->regmap, ISL12022_REG_BETA,
 128                                  ISL12022_BETA_TSE, ISL12022_BETA_TSE);
 129         if (ret) {
 130                 dev_warn(dev, "unable to enable temperature sensor\n");
 131                 return;
 132         }
 133
 134         hwmon = devm_hwmon_device_register_with_info(dev, "isl12022", isl12022,
 135                                                      &isl12022_hwmon_chip_info,
 136                                                      NULL);
 137         if (IS_ERR(hwmon))
 138                 dev_warn(dev, "unable to register hwmon device: %pe\n", hwmon);
 139 }
 140
 141 /*
 142  * In the routines that deal directly with the isl12022 hardware, we use
 143  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
 144  */
 145 static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
 146 {
 147         struct isl12022 *isl12022 = dev_get_drvdata(dev);
 148         struct regmap *regmap = isl12022->regmap;
 149         uint8_t buf[ISL12022_REG_INT + 1];
 150         int ret;
 151
 152         ret = regmap_bulk_read(regmap, ISL12022_REG_SC, buf, sizeof(buf));
 153         if (ret)
 154                 return ret;
 155
 156         if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
 157                 dev_warn(dev,
 158                          "voltage dropped below %u%%, "
 159                          "date and time is not reliable.\n",
 160                          buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
 161         }
 162
 163         dev_dbg(dev,
 164                 "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
 165                 "mday=%02x, mon=%02x, year=%02x, wday=%02x, "
 166                 "sr=%02x, int=%02x",
 167                 __func__,
 168                 buf[ISL12022_REG_SC],
 169                 buf[ISL12022_REG_MN],
 170                 buf[ISL12022_REG_HR],
 171                 buf[ISL12022_REG_DT],
 172                 buf[ISL12022_REG_MO],
 173                 buf[ISL12022_REG_YR],
 174                 buf[ISL12022_REG_DW],
 175                 buf[ISL12022_REG_SR],
 176                 buf[ISL12022_REG_INT]);
 177
 178         tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
 179         tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
 180         tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
 181         tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
 182         tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
 183         tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
 184         tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
 185
 186         dev_dbg(dev, "%s: %ptR\n", __func__, tm);
 187
 188         return 0;
 189 }
 190
 191 static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
 192 {
 193         struct isl12022 *isl12022 = dev_get_drvdata(dev);
 194         struct regmap *regmap = isl12022->regmap;
 195         int ret;
 196         uint8_t buf[ISL12022_REG_DW + 1];
 197
 198         dev_dbg(dev, "%s: %ptR\n", __func__, tm);
 199
 200         /* Ensure the write enable bit is set. */
 201         ret = regmap_update_bits(regmap, ISL12022_REG_INT,
 202                                  ISL12022_INT_WRTC, ISL12022_INT_WRTC);
 203         if (ret)
 204                 return ret;
 205
 206         /* hours, minutes and seconds */
 207         buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
 208         buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
 209         buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
 210
 211         buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
 212
 213         /* month, 1 - 12 */
 214         buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
 215
 216         /* year and century */
 217         buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
 218
 219         buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
 220
 221         return regmap_bulk_write(isl12022->regmap, ISL12022_REG_SC,
 222                                  buf, sizeof(buf));
 223 }
 224
 225 static const struct rtc_class_ops isl12022_rtc_ops = {
 226         .read_time      = isl12022_rtc_read_time,
 227         .set_time       = isl12022_rtc_set_time,
 228 };
 229
 230 static const struct regmap_config regmap_config = {
 231         .reg_bits = 8,
 232         .val_bits = 8,
 233         .use_single_write = true,
 234 };
 235
 236 static int isl12022_probe(struct i2c_client *client)
 237 {
 238         struct isl12022 *isl12022;
 239
 240         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 241                 return -ENODEV;
 242
 243         isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022),
 244                                 GFP_KERNEL);
 245         if (!isl12022)
 246                 return -ENOMEM;
 247         dev_set_drvdata(&client->dev, isl12022);
 248
 249         isl12022->regmap = devm_regmap_init_i2c(client, &regmap_config);
 250         if (IS_ERR(isl12022->regmap)) {
 251                 dev_err(&client->dev, "regmap allocation failed\n");
 252                 return PTR_ERR(isl12022->regmap);
 253         }
 254
 255         isl12022_hwmon_register(&client->dev);
 256
 257         isl12022->rtc = devm_rtc_allocate_device(&client->dev);
 258         if (IS_ERR(isl12022->rtc))
 259                 return PTR_ERR(isl12022->rtc);
 260
 261         isl12022->rtc->ops = &isl12022_rtc_ops;
 262         isl12022->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 263         isl12022->rtc->range_max = RTC_TIMESTAMP_END_2099;
 264
 265         return devm_rtc_register_device(isl12022->rtc);
 266 }
 267
 268 #ifdef CONFIG_OF
 269 static const struct of_device_id isl12022_dt_match[] = {
 270         { .compatible = "isl,isl12022" }, /* for backward compat., don't use */
 271         { .compatible = "isil,isl12022" },
 272         { },
 273 };
 274 MODULE_DEVICE_TABLE(of, isl12022_dt_match);
 275 #endif
 276
 277 static const struct i2c_device_id isl12022_id[] = {
 278         { "isl12022", 0 },
 279         { }
 280 };
 281 MODULE_DEVICE_TABLE(i2c, isl12022_id);
 282
 283 static struct i2c_driver isl12022_driver = {
 284         .driver         = {
 285                 .name   = "rtc-isl12022",
 286 #ifdef CONFIG_OF
 287                 .of_match_table = of_match_ptr(isl12022_dt_match),
 288 #endif
 289         },
 290         .probe_new      = isl12022_probe,
 291         .id_table       = isl12022_id,
 292 };
 293
 294 module_i2c_driver(isl12022_driver);
 295
 296 MODULE_AUTHOR("roman.fietze@telemotive.de");
 297 MODULE_DESCRIPTION("ISL 12022 RTC driver");
 298 MODULE_LICENSE("GPL");