drivers/hwmon/lochnagar-hwmon.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Lochnagar hardware monitoring features
0004  *
0005  * Copyright (c) 2016-2019 Cirrus Logic, Inc. and
0006  *                         Cirrus Logic International Semiconductor Ltd.
0007  *
0008  * Author: Lucas Tanure <tanureal@opensource.cirrus.com>
0009  */
0010
0011 #include <linux/delay.h>
0012 #include <linux/hwmon.h>
0013 #include <linux/hwmon-sysfs.h>
0014 #include <linux/i2c.h>
0015 #include <linux/math64.h>
0016 #include <linux/mfd/lochnagar.h>
0017 #include <linux/mfd/lochnagar2_regs.h>
0018 #include <linux/module.h>
0019 #include <linux/of.h>
0020 #include <linux/of_device.h>
0021 #include <linux/platform_device.h>
0022 #include <linux/regmap.h>
0023
0024 #define LN2_MAX_NSAMPLE 1023
0025 #define LN2_SAMPLE_US   1670
0026
0027 #define LN2_CURR_UNITS  1000
0028 #define LN2_VOLT_UNITS  1000
0029 #define LN2_TEMP_UNITS  1000
0030 #define LN2_PWR_UNITS   1000000
0031
0032 static const char * const lochnagar_chan_names[] = {
0033     "DBVDD1",
0034     "1V8 DSP",
0035     "1V8 CDC",
0036     "VDDCORE DSP",
0037     "AVDD 1V8",
0038     "SYSVDD",
0039     "VDDCORE CDC",
0040     "MICVDD",
0041 };
0042
0043 struct lochnagar_hwmon {
0044     struct regmap *regmap;
0045
0046     long power_nsamples[ARRAY_SIZE(lochnagar_chan_names)];
0047
0048     /* Lock to ensure only a single sensor is read at a time */
0049     struct mutex sensor_lock;
0050 };
0051
0052 enum lochnagar_measure_mode {
0053     LN2_CURR = 0,
0054     LN2_VOLT,
0055     LN2_TEMP,
0056 };
0057
0058 /**
0059  * float_to_long - Convert ieee754 reading from hardware to an integer
0060  *
0061  * @data: Value read from the hardware
0062  * @precision: Units to multiply up to eg. 1000 = milli, 1000000 = micro
0063  *
0064  * Return: Converted integer reading
0065  *
0066  * Depending on the measurement type the hardware returns an ieee754
0067  * floating point value in either volts, amps or celsius. This function
0068  * will convert that into an integer in a smaller unit such as micro-amps
0069  * or milli-celsius. The hardware does not return NaN, so consideration of
0070  * that is not required.
0071  */
0072 static long float_to_long(u32 data, u32 precision)
0073 {
0074     u64 man = data & 0x007FFFFF;
0075     int exp = ((data & 0x7F800000) >> 23) - 127 - 23;
0076     bool negative = data & 0x80000000;
0077     long result;
0078
0079     man = (man + (1 << 23)) * precision;
0080
0081     if (fls64(man) + exp > (int)sizeof(long) * 8 - 1)
0082         result = LONG_MAX;
0083     else if (exp < 0)
0084         result = (man + (1ull << (-exp - 1))) >> -exp;
0085     else
0086         result = man << exp;
0087
0088     return negative ? -result : result;
0089 }
0090
0091 static int do_measurement(struct regmap *regmap, int chan,
0092               enum lochnagar_measure_mode mode, int nsamples)
0093 {
0094     unsigned int val;
0095     int ret;
0096
0097     chan = 1 << (chan + LOCHNAGAR2_IMON_MEASURED_CHANNELS_SHIFT);
0098
0099     ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL1,
0100                LOCHNAGAR2_IMON_ENA_MASK | chan | mode);
0101     if (ret < 0)
0102         return ret;
0103
0104     ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL2, nsamples);
0105     if (ret < 0)
0106         return ret;
0107
0108     ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
0109                LOCHNAGAR2_IMON_CONFIGURE_MASK);
0110     if (ret < 0)
0111         return ret;
0112
0113     ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
0114                     val & LOCHNAGAR2_IMON_DONE_MASK,
0115                     1000, 10000);
0116     if (ret < 0)
0117         return ret;
0118
0119     ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
0120                LOCHNAGAR2_IMON_MEASURE_MASK);
0121     if (ret < 0)
0122         return ret;
0123
0124     /*
0125      * Actual measurement time is ~1.67mS per sample, approximate this
0126      * with a 1.5mS per sample msleep and then poll for success up to
0127      * ~0.17mS * 1023 (LN2_MAX_NSAMPLES). Normally for smaller values
0128      * of nsamples the poll will complete on the first loop due to
0129      * other latency in the system.
0130      */
0131     msleep((nsamples * 3) / 2);
0132
0133     ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
0134                     val & LOCHNAGAR2_IMON_DONE_MASK,
0135                     5000, 200000);
0136     if (ret < 0)
0137         return ret;
0138
0139     return regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3, 0);
0140 }
0141
0142 static int request_data(struct regmap *regmap, int chan, u32 *data)
0143 {
0144     unsigned int val;
0145     int ret;
0146
0147     ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4,
0148                LOCHNAGAR2_IMON_DATA_REQ_MASK |
0149                chan << LOCHNAGAR2_IMON_CH_SEL_SHIFT);
0150     if (ret < 0)
0151         return ret;
0152
0153     ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL4, val,
0154                     val & LOCHNAGAR2_IMON_DATA_RDY_MASK,
0155                     1000, 10000);
0156     if (ret < 0)
0157         return ret;
0158
0159     ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA1, &val);
0160     if (ret < 0)
0161         return ret;
0162
0163     *data = val << 16;
0164
0165     ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA2, &val);
0166     if (ret < 0)
0167         return ret;
0168
0169     *data |= val;
0170
0171     return regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4, 0);
0172 }
0173
0174 static int read_sensor(struct device *dev, int chan,
0175                enum lochnagar_measure_mode mode, int nsamples,
0176                unsigned int precision, long *val)
0177 {
0178     struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
0179     struct regmap *regmap = priv->regmap;
0180     u32 data;
0181     int ret;
0182
0183     mutex_lock(&priv->sensor_lock);
0184
0185     ret = do_measurement(regmap, chan, mode, nsamples);
0186     if (ret < 0) {
0187         dev_err(dev, "Failed to perform measurement: %d\n", ret);
0188         goto error;
0189     }
0190
0191     ret = request_data(regmap, chan, &data);
0192     if (ret < 0) {
0193         dev_err(dev, "Failed to read measurement: %d\n", ret);
0194         goto error;
0195     }
0196
0197     *val = float_to_long(data, precision);
0198
0199 error:
0200     mutex_unlock(&priv->sensor_lock);
0201
0202     return ret;
0203 }
0204
0205 static int read_power(struct device *dev, int chan, long *val)
0206 {
0207     struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
0208     int nsamples = priv->power_nsamples[chan];
0209     u64 power;
0210     int ret;
0211
0212     if (!strcmp("SYSVDD", lochnagar_chan_names[chan])) {
0213         power = 5 * LN2_PWR_UNITS;
0214     } else {
0215         ret = read_sensor(dev, chan, LN2_VOLT, 1, LN2_PWR_UNITS, val);
0216         if (ret < 0)
0217             return ret;
0218
0219         power = abs(*val);
0220     }
0221
0222     ret = read_sensor(dev, chan, LN2_CURR, nsamples, LN2_PWR_UNITS, val);
0223     if (ret < 0)
0224         return ret;
0225
0226     power *= abs(*val);
0227     power = DIV_ROUND_CLOSEST_ULL(power, LN2_PWR_UNITS);
0228
0229     if (power > LONG_MAX)
0230         *val = LONG_MAX;
0231     else
0232         *val = power;
0233
0234     return 0;
0235 }
0236
0237 static umode_t lochnagar_is_visible(const void *drvdata,
0238                     enum hwmon_sensor_types type,
0239                     u32 attr, int chan)
0240 {
0241     switch (type) {
0242     case hwmon_in:
0243         if (!strcmp("SYSVDD", lochnagar_chan_names[chan]))
0244             return 0;
0245         break;
0246     case hwmon_power:
0247         if (attr == hwmon_power_average_interval)
0248             return 0644;
0249         break;
0250     default:
0251         break;
0252     }
0253
0254     return 0444;
0255 }
0256
0257 static int lochnagar_read(struct device *dev, enum hwmon_sensor_types type,
0258               u32 attr, int chan, long *val)
0259 {
0260     struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
0261     int interval;
0262
0263     switch (type) {
0264     case hwmon_in:
0265         return read_sensor(dev, chan, LN2_VOLT, 1, LN2_VOLT_UNITS, val);
0266     case hwmon_curr:
0267         return read_sensor(dev, chan, LN2_CURR, 1, LN2_CURR_UNITS, val);
0268     case hwmon_temp:
0269         return read_sensor(dev, chan, LN2_TEMP, 1, LN2_TEMP_UNITS, val);
0270     case hwmon_power:
0271         switch (attr) {
0272         case hwmon_power_average:
0273             return read_power(dev, chan, val);
0274         case hwmon_power_average_interval:
0275             interval = priv->power_nsamples[chan] * LN2_SAMPLE_US;
0276             *val = DIV_ROUND_CLOSEST(interval, 1000);
0277             return 0;
0278         default:
0279             return -EOPNOTSUPP;
0280         }
0281     default:
0282         return -EOPNOTSUPP;
0283     }
0284 }
0285
0286 static int lochnagar_read_string(struct device *dev,
0287                  enum hwmon_sensor_types type, u32 attr,
0288                  int chan, const char **str)
0289 {
0290     switch (type) {
0291     case hwmon_in:
0292     case hwmon_curr:
0293     case hwmon_power:
0294         *str = lochnagar_chan_names[chan];
0295         return 0;
0296     default:
0297         return -EOPNOTSUPP;
0298     }
0299 }
0300
0301 static int lochnagar_write(struct device *dev, enum hwmon_sensor_types type,
0302                u32 attr, int chan, long val)
0303 {
0304     struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
0305
0306     if (type != hwmon_power || attr != hwmon_power_average_interval)
0307         return -EOPNOTSUPP;
0308
0309     val = clamp_t(long, val, 1, (LN2_MAX_NSAMPLE * LN2_SAMPLE_US) / 1000);
0310     val = DIV_ROUND_CLOSEST(val * 1000, LN2_SAMPLE_US);
0311
0312     priv->power_nsamples[chan] = val;
0313
0314     return 0;
0315 }
0316
0317 static const struct hwmon_ops lochnagar_ops = {
0318     .is_visible = lochnagar_is_visible,
0319     .read = lochnagar_read,
0320     .read_string = lochnagar_read_string,
0321     .write = lochnagar_write,
0322 };
0323
0324 static const struct hwmon_channel_info *lochnagar_info[] = {
0325     HWMON_CHANNEL_INFO(temp,  HWMON_T_INPUT),
0326     HWMON_CHANNEL_INFO(in,    HWMON_I_INPUT | HWMON_I_LABEL,
0327                   HWMON_I_INPUT | HWMON_I_LABEL,
0328                   HWMON_I_INPUT | HWMON_I_LABEL,
0329                   HWMON_I_INPUT | HWMON_I_LABEL,
0330                   HWMON_I_INPUT | HWMON_I_LABEL,
0331                   HWMON_I_INPUT | HWMON_I_LABEL,
0332                   HWMON_I_INPUT | HWMON_I_LABEL,
0333                   HWMON_I_INPUT | HWMON_I_LABEL),
0334     HWMON_CHANNEL_INFO(curr,  HWMON_C_INPUT | HWMON_C_LABEL,
0335                   HWMON_C_INPUT | HWMON_C_LABEL,
0336                   HWMON_C_INPUT | HWMON_C_LABEL,
0337                   HWMON_C_INPUT | HWMON_C_LABEL,
0338                   HWMON_C_INPUT | HWMON_C_LABEL,
0339                   HWMON_C_INPUT | HWMON_C_LABEL,
0340                   HWMON_C_INPUT | HWMON_C_LABEL,
0341                   HWMON_C_INPUT | HWMON_C_LABEL),
0342     HWMON_CHANNEL_INFO(power, HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
0343                   HWMON_P_LABEL,
0344                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
0345                   HWMON_P_LABEL,
0346                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
0347                   HWMON_P_LABEL,
0348                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
0349                   HWMON_P_LABEL,
0350                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
0351                   HWMON_P_LABEL,
0352                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
0353                   HWMON_P_LABEL,
0354                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
0355                   HWMON_P_LABEL,
0356                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
0357                   HWMON_P_LABEL),
0358     NULL
0359 };
0360
0361 static const struct hwmon_chip_info lochnagar_chip_info = {
0362     .ops = &lochnagar_ops,
0363     .info = lochnagar_info,
0364 };
0365
0366 static const struct of_device_id lochnagar_of_match[] = {
0367     { .compatible = "cirrus,lochnagar2-hwmon" },
0368     {}
0369 };
0370 MODULE_DEVICE_TABLE(of, lochnagar_of_match);
0371
0372 static int lochnagar_hwmon_probe(struct platform_device *pdev)
0373 {
0374     struct device *dev = &pdev->dev;
0375     struct device *hwmon_dev;
0376     struct lochnagar_hwmon *priv;
0377     int i;
0378
0379     priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
0380     if (!priv)
0381         return -ENOMEM;
0382
0383     mutex_init(&priv->sensor_lock);
0384
0385     priv->regmap = dev_get_regmap(dev->parent, NULL);
0386     if (!priv->regmap) {
0387         dev_err(dev, "No register map found\n");
0388         return -EINVAL;
0389     }
0390
0391     for (i = 0; i < ARRAY_SIZE(priv->power_nsamples); i++)
0392         priv->power_nsamples[i] = 96;
0393
0394     hwmon_dev = devm_hwmon_device_register_with_info(dev, "Lochnagar", priv,
0395                              &lochnagar_chip_info,
0396                              NULL);
0397
0398     return PTR_ERR_OR_ZERO(hwmon_dev);
0399 }
0400
0401 static struct platform_driver lochnagar_hwmon_driver = {
0402     .driver = {
0403         .name = "lochnagar-hwmon",
0404         .of_match_table = lochnagar_of_match,
0405     },
0406     .probe = lochnagar_hwmon_probe,
0407 };
0408 module_platform_driver(lochnagar_hwmon_driver);
0409
0410 MODULE_AUTHOR("Lucas Tanure <tanureal@opensource.cirrus.com>");
0411 MODULE_DESCRIPTION("Lochnagar hardware monitoring features");
0412 MODULE_LICENSE("GPL");