drivers/hwmon/adm1177.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * ADM1177 Hot Swap Controller and Digital Power Monitor with Soft Start Pin
   4  *
   5  * Copyright 2015-2019 Analog Devices Inc.
   6  */
   7
   8 #include <linux/bits.h>
   9 #include <linux/device.h>
  10 #include <linux/hwmon.h>
  11 #include <linux/i2c.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/regulator/consumer.h>
  15
  16 /*  Command Byte Operations */
  17 #define ADM1177_CMD_V_CONT      BIT(0)
  18 #define ADM1177_CMD_I_CONT      BIT(2)
  19 #define ADM1177_CMD_VRANGE      BIT(4)
  20
  21 /* Extended Register */
  22 #define ADM1177_REG_ALERT_TH    2
  23
  24 #define ADM1177_BITS            12
  25
  26 /**
  27  * struct adm1177_state - driver instance specific data
  28  * @client:             pointer to i2c client
  29  * @r_sense_uohm:       current sense resistor value
  30  * @alert_threshold_ua: current limit for shutdown
  31  * @vrange_high:        internal voltage divider
  32  */
  33 struct adm1177_state {
  34         struct i2c_client       *client;
  35         u32                     r_sense_uohm;
  36         u32                     alert_threshold_ua;
  37         bool                    vrange_high;
  38 };
  39
  40 static int adm1177_read_raw(struct adm1177_state *st, u8 num, u8 *data)
  41 {
  42         return i2c_master_recv(st->client, data, num);
  43 }
  44
  45 static int adm1177_write_cmd(struct adm1177_state *st, u8 cmd)
  46 {
  47         return i2c_smbus_write_byte(st->client, cmd);
  48 }
  49
  50 static int adm1177_write_alert_thr(struct adm1177_state *st,
  51                                    u32 alert_threshold_ua)
  52 {
  53         u64 val;
  54         int ret;
  55
  56         val = 0xFFULL * alert_threshold_ua * st->r_sense_uohm;
  57         val = div_u64(val, 105840000U);
  58         val = div_u64(val, 1000U);
  59         if (val > 0xFF)
  60                 val = 0xFF;
  61
  62         ret = i2c_smbus_write_byte_data(st->client, ADM1177_REG_ALERT_TH,
  63                                         val);
  64         if (ret)
  65                 return ret;
  66
  67         st->alert_threshold_ua = alert_threshold_ua;
  68         return 0;
  69 }
  70
  71 static int adm1177_read(struct device *dev, enum hwmon_sensor_types type,
  72                         u32 attr, int channel, long *val)
  73 {
  74         struct adm1177_state *st = dev_get_drvdata(dev);
  75         u8 data[3];
  76         long dummy;
  77         int ret;
  78
  79         switch (type) {
  80         case hwmon_curr:
  81                 switch (attr) {
  82                 case hwmon_curr_input:
  83                         ret = adm1177_read_raw(st, 3, data);
  84                         if (ret < 0)
  85                                 return ret;
  86                         dummy = (data[1] << 4) | (data[2] & 0xF);
  87                         /*
  88                          * convert to milliamperes
  89                          * ((105.84mV / 4096) x raw) / senseResistor(ohm)
  90                          */
  91                         *val = div_u64((105840000ull * dummy),
  92                                        4096 * st->r_sense_uohm);
  93                         return 0;
  94                 case hwmon_curr_max_alarm:
  95                         *val = st->alert_threshold_ua;
  96                         return 0;
  97                 default:
  98                         return -EOPNOTSUPP;
  99                 }
 100         case hwmon_in:
 101                 ret = adm1177_read_raw(st, 3, data);
 102                 if (ret < 0)
 103                         return ret;
 104                 dummy = (data[0] << 4) | (data[2] >> 4);
 105                 /*
 106                  * convert to millivolts based on resistor devision
 107                  * (V_fullscale / 4096) * raw
 108                  */
 109                 if (st->vrange_high)
 110                         dummy *= 26350;
 111                 else
 112                         dummy *= 6650;
 113
 114                 *val = DIV_ROUND_CLOSEST(dummy, 4096);
 115                 return 0;
 116         default:
 117                 return -EOPNOTSUPP;
 118         }
 119 }
 120
 121 static int adm1177_write(struct device *dev, enum hwmon_sensor_types type,
 122                          u32 attr, int channel, long val)
 123 {
 124         struct adm1177_state *st = dev_get_drvdata(dev);
 125
 126         switch (type) {
 127         case hwmon_curr:
 128                 switch (attr) {
 129                 case hwmon_curr_max_alarm:
 130                         adm1177_write_alert_thr(st, val);
 131                         return 0;
 132                 default:
 133                         return -EOPNOTSUPP;
 134                 }
 135         default:
 136                 return -EOPNOTSUPP;
 137         }
 138 }
 139
 140 static umode_t adm1177_is_visible(const void *data,
 141                                   enum hwmon_sensor_types type,
 142                                   u32 attr, int channel)
 143 {
 144         const struct adm1177_state *st = data;
 145
 146         switch (type) {
 147         case hwmon_in:
 148                 switch (attr) {
 149                 case hwmon_in_input:
 150                         return 0444;
 151                 }
 152                 break;
 153         case hwmon_curr:
 154                 switch (attr) {
 155                 case hwmon_curr_input:
 156                         if (st->r_sense_uohm)
 157                                 return 0444;
 158                         return 0;
 159                 case hwmon_curr_max_alarm:
 160                         if (st->r_sense_uohm)
 161                                 return 0644;
 162                         return 0;
 163                 }
 164                 break;
 165         default:
 166                 break;
 167         }
 168         return 0;
 169 }
 170
 171 static const struct hwmon_channel_info * const adm1177_info[] = {
 172         HWMON_CHANNEL_INFO(curr,
 173                            HWMON_C_INPUT | HWMON_C_MAX_ALARM),
 174         HWMON_CHANNEL_INFO(in,
 175                            HWMON_I_INPUT),
 176         NULL
 177 };
 178
 179 static const struct hwmon_ops adm1177_hwmon_ops = {
 180         .is_visible = adm1177_is_visible,
 181         .read = adm1177_read,
 182         .write = adm1177_write,
 183 };
 184
 185 static const struct hwmon_chip_info adm1177_chip_info = {
 186         .ops = &adm1177_hwmon_ops,
 187         .info = adm1177_info,
 188 };
 189
 190 static int adm1177_probe(struct i2c_client *client)
 191 {
 192         struct device *dev = &client->dev;
 193         struct device *hwmon_dev;
 194         struct adm1177_state *st;
 195         u32 alert_threshold_ua;
 196         int ret;
 197
 198         st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
 199         if (!st)
 200                 return -ENOMEM;
 201
 202         st->client = client;
 203
 204         ret = devm_regulator_get_enable_optional(&client->dev, "vref");
 205         if (ret == -EPROBE_DEFER)
 206                 return -EPROBE_DEFER;
 207
 208         if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
 209                                      &st->r_sense_uohm))
 210                 st->r_sense_uohm = 0;
 211         if (device_property_read_u32(dev, "adi,shutdown-threshold-microamp",
 212                                      &alert_threshold_ua)) {
 213                 if (st->r_sense_uohm)
 214                         /*
 215                          * set maximum default value from datasheet based on
 216                          * shunt-resistor
 217                          */
 218                         alert_threshold_ua = div_u64(105840000000,
 219                                                      st->r_sense_uohm);
 220                 else
 221                         alert_threshold_ua = 0;
 222         }
 223         st->vrange_high = device_property_read_bool(dev,
 224                                                     "adi,vrange-high-enable");
 225         if (alert_threshold_ua && st->r_sense_uohm)
 226                 adm1177_write_alert_thr(st, alert_threshold_ua);
 227
 228         ret = adm1177_write_cmd(st, ADM1177_CMD_V_CONT |
 229                                     ADM1177_CMD_I_CONT |
 230                                     (st->vrange_high ? 0 : ADM1177_CMD_VRANGE));
 231         if (ret)
 232                 return ret;
 233
 234         hwmon_dev =
 235                 devm_hwmon_device_register_with_info(dev, client->name, st,
 236                                                      &adm1177_chip_info, NULL);
 237         return PTR_ERR_OR_ZERO(hwmon_dev);
 238 }
 239
 240 static const struct i2c_device_id adm1177_id[] = {
 241         {"adm1177", 0},
 242         {}
 243 };
 244 MODULE_DEVICE_TABLE(i2c, adm1177_id);
 245
 246 static const struct of_device_id adm1177_dt_ids[] = {
 247         { .compatible = "adi,adm1177" },
 248         {},
 249 };
 250 MODULE_DEVICE_TABLE(of, adm1177_dt_ids);
 251
 252 static struct i2c_driver adm1177_driver = {
 253         .driver = {
 254                 .name = "adm1177",
 255                 .of_match_table = adm1177_dt_ids,
 256         },
 257         .probe = adm1177_probe,
 258         .id_table = adm1177_id,
 259 };
 260 module_i2c_driver(adm1177_driver);
 261
 262 MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
 263 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 264 MODULE_DESCRIPTION("Analog Devices ADM1177 ADC driver");
 265 MODULE_LICENSE("GPL v2");