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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Driver for Texas Instruments INA238 power monitor chip4 * Datasheet: https://www.ti.com/product/ina2385 *6 * Copyright (C) 2021 Nathan Rossi <nathan.rossi@digi.com>7 */8 9#include <linux/err.h>10#include <linux/hwmon.h>11#include <linux/i2c.h>12#include <linux/init.h>13#include <linux/kernel.h>14#include <linux/module.h>15#include <linux/of.h>16#include <linux/regmap.h>17 18#include <linux/platform_data/ina2xx.h>19 20/* INA238 register definitions */21#define INA238_CONFIG 0x022#define INA238_ADC_CONFIG 0x123#define INA238_SHUNT_CALIBRATION 0x224#define INA238_SHUNT_VOLTAGE 0x425#define INA238_BUS_VOLTAGE 0x526#define INA238_DIE_TEMP 0x627#define INA238_CURRENT 0x728#define INA238_POWER 0x829#define INA238_DIAG_ALERT 0xb30#define INA238_SHUNT_OVER_VOLTAGE 0xc31#define INA238_SHUNT_UNDER_VOLTAGE 0xd32#define INA238_BUS_OVER_VOLTAGE 0xe33#define INA238_BUS_UNDER_VOLTAGE 0xf34#define INA238_TEMP_LIMIT 0x1035#define INA238_POWER_LIMIT 0x1136#define INA238_DEVICE_ID 0x3f /* not available on INA237 */37 38#define INA238_CONFIG_ADCRANGE BIT(4)39 40#define INA238_DIAG_ALERT_TMPOL BIT(7)41#define INA238_DIAG_ALERT_SHNTOL BIT(6)42#define INA238_DIAG_ALERT_SHNTUL BIT(5)43#define INA238_DIAG_ALERT_BUSOL BIT(4)44#define INA238_DIAG_ALERT_BUSUL BIT(3)45#define INA238_DIAG_ALERT_POL BIT(2)46 47#define INA238_REGISTERS 0x1148 49#define INA238_RSHUNT_DEFAULT 10000 /* uOhm */50 51/* Default configuration of device on reset. */52#define INA238_CONFIG_DEFAULT 053/* 16 sample averaging, 1052us conversion time, continuous mode */54#define INA238_ADC_CONFIG_DEFAULT 0xfb6a55/* Configure alerts to be based on averaged value (SLOWALERT) */56#define INA238_DIAG_ALERT_DEFAULT 0x200057/*58 * This driver uses a fixed calibration value in order to scale current/power59 * based on a fixed shunt resistor value. This allows for conversion within the60 * device to avoid integer limits whilst current/power accuracy is scaled61 * relative to the shunt resistor value within the driver. This is similar to62 * how the ina2xx driver handles current/power scaling.63 *64 * The end result of this is that increasing shunt values (from a fixed 20 mOhm65 * shunt) increase the effective current/power accuracy whilst limiting the66 * range and decreasing shunt values decrease the effective accuracy but67 * increase the range.68 *69 * The value of the Current register is calculated given the following:70 * Current (A) = (shunt voltage register * 5) * calibration / 8192071 *72 * The maximum shunt voltage is 163.835 mV (0x7fff, ADC_RANGE = 0, gain = 4).73 * With the maximum current value of 0x7fff and a fixed shunt value results in74 * a calibration value of 16384 (0x4000).75 *76 * 0x7fff = (0x7fff * 5) * calibration / 8192077 * calibration = 0x400078 *79 * Equivalent calibration is applied for the Power register (maximum value for80 * bus voltage is 102396.875 mV, 0x7fff), where the maximum power that can81 * occur is ~16776192 uW (register value 0x147a8):82 *83 * This scaling means the resulting values for Current and Power registers need84 * to be scaled by the difference between the fixed shunt resistor and the85 * actual shunt resistor:86 *87 * shunt = 0x4000 / (819.2 * 10^6) / 0.001 = 20000 uOhms (with 1mA/lsb)88 *89 * Current (mA) = register value * 20000 / rshunt / 4 * gain90 * Power (W) = 0.2 * register value * 20000 / rshunt / 4 * gain91 */92#define INA238_CALIBRATION_VALUE 1638493#define INA238_FIXED_SHUNT 2000094 95#define INA238_SHUNT_VOLTAGE_LSB 5 /* 5 uV/lsb */96#define INA238_BUS_VOLTAGE_LSB 3125 /* 3.125 mV/lsb */97#define INA238_DIE_TEMP_LSB 125 /* 125 mC/lsb */98 99static const struct regmap_config ina238_regmap_config = {100 .max_register = INA238_REGISTERS,101 .reg_bits = 8,102 .val_bits = 16,103};104 105struct ina238_data {106 struct i2c_client *client;107 struct mutex config_lock;108 struct regmap *regmap;109 u32 rshunt;110 int gain;111};112 113static int ina238_read_reg24(const struct i2c_client *client, u8 reg, u32 *val)114{115 u8 data[3];116 int err;117 118 /* 24-bit register read */119 err = i2c_smbus_read_i2c_block_data(client, reg, 3, data);120 if (err < 0)121 return err;122 if (err != 3)123 return -EIO;124 *val = (data[0] << 16) | (data[1] << 8) | data[2];125 126 return 0;127}128 129static int ina238_read_in(struct device *dev, u32 attr, int channel,130 long *val)131{132 struct ina238_data *data = dev_get_drvdata(dev);133 int reg, mask;134 int regval;135 int err;136 137 switch (channel) {138 case 0:139 switch (attr) {140 case hwmon_in_input:141 reg = INA238_SHUNT_VOLTAGE;142 break;143 case hwmon_in_max:144 reg = INA238_SHUNT_OVER_VOLTAGE;145 break;146 case hwmon_in_min:147 reg = INA238_SHUNT_UNDER_VOLTAGE;148 break;149 case hwmon_in_max_alarm:150 reg = INA238_DIAG_ALERT;151 mask = INA238_DIAG_ALERT_SHNTOL;152 break;153 case hwmon_in_min_alarm:154 reg = INA238_DIAG_ALERT;155 mask = INA238_DIAG_ALERT_SHNTUL;156 break;157 default:158 return -EOPNOTSUPP;159 }160 break;161 case 1:162 switch (attr) {163 case hwmon_in_input:164 reg = INA238_BUS_VOLTAGE;165 break;166 case hwmon_in_max:167 reg = INA238_BUS_OVER_VOLTAGE;168 break;169 case hwmon_in_min:170 reg = INA238_BUS_UNDER_VOLTAGE;171 break;172 case hwmon_in_max_alarm:173 reg = INA238_DIAG_ALERT;174 mask = INA238_DIAG_ALERT_BUSOL;175 break;176 case hwmon_in_min_alarm:177 reg = INA238_DIAG_ALERT;178 mask = INA238_DIAG_ALERT_BUSUL;179 break;180 default:181 return -EOPNOTSUPP;182 }183 break;184 default:185 return -EOPNOTSUPP;186 }187 188 err = regmap_read(data->regmap, reg, ®val);189 if (err < 0)190 return err;191 192 switch (attr) {193 case hwmon_in_input:194 case hwmon_in_max:195 case hwmon_in_min:196 /* signed register, value in mV */197 regval = (s16)regval;198 if (channel == 0)199 /* gain of 1 -> LSB / 4 */200 *val = (regval * INA238_SHUNT_VOLTAGE_LSB) /201 (1000 * (4 - data->gain + 1));202 else203 *val = (regval * INA238_BUS_VOLTAGE_LSB) / 1000;204 break;205 case hwmon_in_max_alarm:206 case hwmon_in_min_alarm:207 *val = !!(regval & mask);208 break;209 }210 211 return 0;212}213 214static int ina238_write_in(struct device *dev, u32 attr, int channel,215 long val)216{217 struct ina238_data *data = dev_get_drvdata(dev);218 int regval;219 220 if (attr != hwmon_in_max && attr != hwmon_in_min)221 return -EOPNOTSUPP;222 223 /* convert decimal to register value */224 switch (channel) {225 case 0:226 /* signed value, clamp to max range +/-163 mV */227 regval = clamp_val(val, -163, 163);228 regval = (regval * 1000 * (4 - data->gain + 1)) /229 INA238_SHUNT_VOLTAGE_LSB;230 regval = clamp_val(regval, S16_MIN, S16_MAX);231 232 switch (attr) {233 case hwmon_in_max:234 return regmap_write(data->regmap,235 INA238_SHUNT_OVER_VOLTAGE, regval);236 case hwmon_in_min:237 return regmap_write(data->regmap,238 INA238_SHUNT_UNDER_VOLTAGE, regval);239 default:240 return -EOPNOTSUPP;241 }242 case 1:243 /* signed value, positive values only. Clamp to max 102.396 V */244 regval = clamp_val(val, 0, 102396);245 regval = (regval * 1000) / INA238_BUS_VOLTAGE_LSB;246 regval = clamp_val(regval, 0, S16_MAX);247 248 switch (attr) {249 case hwmon_in_max:250 return regmap_write(data->regmap,251 INA238_BUS_OVER_VOLTAGE, regval);252 case hwmon_in_min:253 return regmap_write(data->regmap,254 INA238_BUS_UNDER_VOLTAGE, regval);255 default:256 return -EOPNOTSUPP;257 }258 default:259 return -EOPNOTSUPP;260 }261}262 263static int ina238_read_current(struct device *dev, u32 attr, long *val)264{265 struct ina238_data *data = dev_get_drvdata(dev);266 int regval;267 int err;268 269 switch (attr) {270 case hwmon_curr_input:271 err = regmap_read(data->regmap, INA238_CURRENT, ®val);272 if (err < 0)273 return err;274 275 /* Signed register, fixed 1mA current lsb. result in mA */276 *val = div_s64((s16)regval * INA238_FIXED_SHUNT * data->gain,277 data->rshunt * 4);278 break;279 default:280 return -EOPNOTSUPP;281 }282 283 return 0;284}285 286static int ina238_read_power(struct device *dev, u32 attr, long *val)287{288 struct ina238_data *data = dev_get_drvdata(dev);289 long long power;290 int regval;291 int err;292 293 switch (attr) {294 case hwmon_power_input:295 err = ina238_read_reg24(data->client, INA238_POWER, ®val);296 if (err)297 return err;298 299 /* Fixed 1mA lsb, scaled by 1000000 to have result in uW */300 power = div_u64(regval * 1000ULL * INA238_FIXED_SHUNT *301 data->gain, 20 * data->rshunt);302 /* Clamp value to maximum value of long */303 *val = clamp_val(power, 0, LONG_MAX);304 break;305 case hwmon_power_max:306 err = regmap_read(data->regmap, INA238_POWER_LIMIT, ®val);307 if (err)308 return err;309 310 /*311 * Truncated 24-bit compare register, lower 8-bits are312 * truncated. Same conversion to/from uW as POWER register.313 */314 power = div_u64((regval << 8) * 1000ULL * INA238_FIXED_SHUNT *315 data->gain, 20 * data->rshunt);316 /* Clamp value to maximum value of long */317 *val = clamp_val(power, 0, LONG_MAX);318 break;319 case hwmon_power_max_alarm:320 err = regmap_read(data->regmap, INA238_DIAG_ALERT, ®val);321 if (err)322 return err;323 324 *val = !!(regval & INA238_DIAG_ALERT_POL);325 break;326 default:327 return -EOPNOTSUPP;328 }329 330 return 0;331}332 333static int ina238_write_power(struct device *dev, u32 attr, long val)334{335 struct ina238_data *data = dev_get_drvdata(dev);336 long regval;337 338 if (attr != hwmon_power_max)339 return -EOPNOTSUPP;340 341 /*342 * Unsigned postive values. Compared against the 24-bit power register,343 * lower 8-bits are truncated. Same conversion to/from uW as POWER344 * register.345 */346 regval = clamp_val(val, 0, LONG_MAX);347 regval = div_u64(val * 20ULL * data->rshunt,348 1000ULL * INA238_FIXED_SHUNT * data->gain);349 regval = clamp_val(regval >> 8, 0, U16_MAX);350 351 return regmap_write(data->regmap, INA238_POWER_LIMIT, regval);352}353 354static int ina238_read_temp(struct device *dev, u32 attr, long *val)355{356 struct ina238_data *data = dev_get_drvdata(dev);357 int regval;358 int err;359 360 switch (attr) {361 case hwmon_temp_input:362 err = regmap_read(data->regmap, INA238_DIE_TEMP, ®val);363 if (err)364 return err;365 366 /* Signed, bits 15-4 of register, result in mC */367 *val = ((s16)regval >> 4) * INA238_DIE_TEMP_LSB;368 break;369 case hwmon_temp_max:370 err = regmap_read(data->regmap, INA238_TEMP_LIMIT, ®val);371 if (err)372 return err;373 374 /* Signed, bits 15-4 of register, result in mC */375 *val = ((s16)regval >> 4) * INA238_DIE_TEMP_LSB;376 break;377 case hwmon_temp_max_alarm:378 err = regmap_read(data->regmap, INA238_DIAG_ALERT, ®val);379 if (err)380 return err;381 382 *val = !!(regval & INA238_DIAG_ALERT_TMPOL);383 break;384 default:385 return -EOPNOTSUPP;386 }387 388 return 0;389}390 391static int ina238_write_temp(struct device *dev, u32 attr, long val)392{393 struct ina238_data *data = dev_get_drvdata(dev);394 int regval;395 396 if (attr != hwmon_temp_max)397 return -EOPNOTSUPP;398 399 /* Signed, bits 15-4 of register */400 regval = (val / INA238_DIE_TEMP_LSB) << 4;401 regval = clamp_val(regval, S16_MIN, S16_MAX) & 0xfff0;402 403 return regmap_write(data->regmap, INA238_TEMP_LIMIT, regval);404}405 406static int ina238_read(struct device *dev, enum hwmon_sensor_types type,407 u32 attr, int channel, long *val)408{409 switch (type) {410 case hwmon_in:411 return ina238_read_in(dev, attr, channel, val);412 case hwmon_curr:413 return ina238_read_current(dev, attr, val);414 case hwmon_power:415 return ina238_read_power(dev, attr, val);416 case hwmon_temp:417 return ina238_read_temp(dev, attr, val);418 default:419 return -EOPNOTSUPP;420 }421 return 0;422}423 424static int ina238_write(struct device *dev, enum hwmon_sensor_types type,425 u32 attr, int channel, long val)426{427 struct ina238_data *data = dev_get_drvdata(dev);428 int err;429 430 mutex_lock(&data->config_lock);431 432 switch (type) {433 case hwmon_in:434 err = ina238_write_in(dev, attr, channel, val);435 break;436 case hwmon_power:437 err = ina238_write_power(dev, attr, val);438 break;439 case hwmon_temp:440 err = ina238_write_temp(dev, attr, val);441 break;442 default:443 err = -EOPNOTSUPP;444 break;445 }446 447 mutex_unlock(&data->config_lock);448 return err;449}450 451static umode_t ina238_is_visible(const void *drvdata,452 enum hwmon_sensor_types type,453 u32 attr, int channel)454{455 switch (type) {456 case hwmon_in:457 switch (attr) {458 case hwmon_in_input:459 case hwmon_in_max_alarm:460 case hwmon_in_min_alarm:461 return 0444;462 case hwmon_in_max:463 case hwmon_in_min:464 return 0644;465 default:466 return 0;467 }468 case hwmon_curr:469 switch (attr) {470 case hwmon_curr_input:471 return 0444;472 default:473 return 0;474 }475 case hwmon_power:476 switch (attr) {477 case hwmon_power_input:478 case hwmon_power_max_alarm:479 return 0444;480 case hwmon_power_max:481 return 0644;482 default:483 return 0;484 }485 case hwmon_temp:486 switch (attr) {487 case hwmon_temp_input:488 case hwmon_temp_max_alarm:489 return 0444;490 case hwmon_temp_max:491 return 0644;492 default:493 return 0;494 }495 default:496 return 0;497 }498}499 500#define INA238_HWMON_IN_CONFIG (HWMON_I_INPUT | \501 HWMON_I_MAX | HWMON_I_MAX_ALARM | \502 HWMON_I_MIN | HWMON_I_MIN_ALARM)503 504static const struct hwmon_channel_info * const ina238_info[] = {505 HWMON_CHANNEL_INFO(in,506 /* 0: shunt voltage */507 INA238_HWMON_IN_CONFIG,508 /* 1: bus voltage */509 INA238_HWMON_IN_CONFIG),510 HWMON_CHANNEL_INFO(curr,511 /* 0: current through shunt */512 HWMON_C_INPUT),513 HWMON_CHANNEL_INFO(power,514 /* 0: power */515 HWMON_P_INPUT | HWMON_P_MAX | HWMON_P_MAX_ALARM),516 HWMON_CHANNEL_INFO(temp,517 /* 0: die temperature */518 HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_ALARM),519 NULL520};521 522static const struct hwmon_ops ina238_hwmon_ops = {523 .is_visible = ina238_is_visible,524 .read = ina238_read,525 .write = ina238_write,526};527 528static const struct hwmon_chip_info ina238_chip_info = {529 .ops = &ina238_hwmon_ops,530 .info = ina238_info,531};532 533static int ina238_probe(struct i2c_client *client)534{535 struct ina2xx_platform_data *pdata = dev_get_platdata(&client->dev);536 struct device *dev = &client->dev;537 struct device *hwmon_dev;538 struct ina238_data *data;539 int config;540 int ret;541 542 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);543 if (!data)544 return -ENOMEM;545 546 data->client = client;547 mutex_init(&data->config_lock);548 549 data->regmap = devm_regmap_init_i2c(client, &ina238_regmap_config);550 if (IS_ERR(data->regmap)) {551 dev_err(dev, "failed to allocate register map\n");552 return PTR_ERR(data->regmap);553 }554 555 /* load shunt value */556 data->rshunt = INA238_RSHUNT_DEFAULT;557 if (device_property_read_u32(dev, "shunt-resistor", &data->rshunt) < 0 && pdata)558 data->rshunt = pdata->shunt_uohms;559 if (data->rshunt == 0) {560 dev_err(dev, "invalid shunt resister value %u\n", data->rshunt);561 return -EINVAL;562 }563 564 /* load shunt gain value */565 if (device_property_read_u32(dev, "ti,shunt-gain", &data->gain) < 0)566 data->gain = 4; /* Default of ADCRANGE = 0 */567 if (data->gain != 1 && data->gain != 4) {568 dev_err(dev, "invalid shunt gain value %u\n", data->gain);569 return -EINVAL;570 }571 572 /* Setup CONFIG register */573 config = INA238_CONFIG_DEFAULT;574 if (data->gain == 1)575 config |= INA238_CONFIG_ADCRANGE; /* ADCRANGE = 1 is /1 */576 ret = regmap_write(data->regmap, INA238_CONFIG, config);577 if (ret < 0) {578 dev_err(dev, "error configuring the device: %d\n", ret);579 return -ENODEV;580 }581 582 /* Setup ADC_CONFIG register */583 ret = regmap_write(data->regmap, INA238_ADC_CONFIG,584 INA238_ADC_CONFIG_DEFAULT);585 if (ret < 0) {586 dev_err(dev, "error configuring the device: %d\n", ret);587 return -ENODEV;588 }589 590 /* Setup SHUNT_CALIBRATION register with fixed value */591 ret = regmap_write(data->regmap, INA238_SHUNT_CALIBRATION,592 INA238_CALIBRATION_VALUE);593 if (ret < 0) {594 dev_err(dev, "error configuring the device: %d\n", ret);595 return -ENODEV;596 }597 598 /* Setup alert/alarm configuration */599 ret = regmap_write(data->regmap, INA238_DIAG_ALERT,600 INA238_DIAG_ALERT_DEFAULT);601 if (ret < 0) {602 dev_err(dev, "error configuring the device: %d\n", ret);603 return -ENODEV;604 }605 606 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,607 &ina238_chip_info,608 NULL);609 if (IS_ERR(hwmon_dev))610 return PTR_ERR(hwmon_dev);611 612 dev_info(dev, "power monitor %s (Rshunt = %u uOhm, gain = %u)\n",613 client->name, data->rshunt, data->gain);614 615 return 0;616}617 618static const struct i2c_device_id ina238_id[] = {619 { "ina238" },620 { }621};622MODULE_DEVICE_TABLE(i2c, ina238_id);623 624static const struct of_device_id __maybe_unused ina238_of_match[] = {625 { .compatible = "ti,ina237" },626 { .compatible = "ti,ina238" },627 { },628};629MODULE_DEVICE_TABLE(of, ina238_of_match);630 631static struct i2c_driver ina238_driver = {632 .driver = {633 .name = "ina238",634 .of_match_table = of_match_ptr(ina238_of_match),635 },636 .probe = ina238_probe,637 .id_table = ina238_id,638};639 640module_i2c_driver(ina238_driver);641 642MODULE_AUTHOR("Nathan Rossi <nathan.rossi@digi.com>");643MODULE_DESCRIPTION("ina238 driver");644MODULE_LICENSE("GPL");645