--- /dev/null
+Kernel Driver Lochnagar
+========================
+
+Supported systems:
+ * Cirrus Logic : Lochnagar 2
+
+Author: Lucas A. Tanure Alves
+
+Description
+-----------
+
+Lochnagar 2 features built-in Current Monitor circuitry that allows for the
+measurement of both voltage and current on up to eight of the supply voltage
+rails provided to the minicards. The Current Monitor does not require any
+hardware modifications or external circuitry to operate.
+
+The current and voltage measurements are obtained through the standard register
+map interface to the Lochnagar board controller, and can therefore be monitored
+by software.
+
+Sysfs attributes
+----------------
+
+temp1_input The Lochnagar board temperature (milliCelsius)
+in0_input Measured voltage for DBVDD1 (milliVolts)
+in0_label "DBVDD1"
+curr1_input Measured current for DBVDD1 (milliAmps)
+curr1_label "DBVDD1"
+power1_average Measured average power for DBVDD1 (microWatts)
+power1_average_interval Power averaging time input valid from 1 to 1708mS
+power1_label "DBVDD1"
+in1_input Measured voltage for 1V8 DSP (milliVolts)
+in1_label "1V8 DSP"
+curr2_input Measured current for 1V8 DSP (milliAmps)
+curr2_label "1V8 DSP"
+power2_average Measured average power for 1V8 DSP (microWatts)
+power2_average_interval Power averaging time input valid from 1 to 1708mS
+power2_label "1V8 DSP"
+in2_input Measured voltage for 1V8 CDC (milliVolts)
+in2_label "1V8 CDC"
+curr3_input Measured current for 1V8 CDC (milliAmps)
+curr3_label "1V8 CDC"
+power3_average Measured average power for 1V8 CDC (microWatts)
+power3_average_interval Power averaging time input valid from 1 to 1708mS
+power3_label "1V8 CDC"
+in3_input Measured voltage for VDDCORE DSP (milliVolts)
+in3_label "VDDCORE DSP"
+curr4_input Measured current for VDDCORE DSP (milliAmps)
+curr4_label "VDDCORE DSP"
+power4_average Measured average power for VDDCORE DSP (microWatts)
+power4_average_interval Power averaging time input valid from 1 to 1708mS
+power4_label "VDDCORE DSP"
+in4_input Measured voltage for AVDD 1V8 (milliVolts)
+in4_label "AVDD 1V8"
+curr5_input Measured current for AVDD 1V8 (milliAmps)
+curr5_label "AVDD 1V8"
+power5_average Measured average power for AVDD 1V8 (microWatts)
+power5_average_interval Power averaging time input valid from 1 to 1708mS
+power5_label "AVDD 1V8"
+curr6_input Measured current for SYSVDD (milliAmps)
+curr6_label "SYSVDD"
+power6_average Measured average power for SYSVDD (microWatts)
+power6_average_interval Power averaging time input valid from 1 to 1708mS
+power6_label "SYSVDD"
+in6_input Measured voltage for VDDCORE CDC (milliVolts)
+in6_label "VDDCORE CDC"
+curr7_input Measured current for VDDCORE CDC (milliAmps)
+curr7_label "VDDCORE CDC"
+power7_average Measured average power for VDDCORE CDC (microWatts)
+power7_average_interval Power averaging time input valid from 1 to 1708mS
+power7_label "VDDCORE CDC"
+in7_input Measured voltage for MICVDD (milliVolts)
+in7_label "MICVDD"
+curr8_input Measured current for MICVDD (milliAmps)
+curr8_label "MICVDD"
+power8_average Measured average power for MICVDD (microWatts)
+power8_average_interval Power averaging time input valid from 1 to 1708mS
+power8_label "MICVDD"
+
+Note: It is not possible to measure voltage on the SYSVDD rail.
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Lochnagar hardware monitoring features
+ *
+ * Copyright (c) 2016-2019 Cirrus Logic, Inc. and
+ * Cirrus Logic International Semiconductor Ltd.
+ *
+ * Author: Lucas Tanure <tanureal@opensource.cirrus.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/math64.h>
+#include <linux/mfd/lochnagar.h>
+#include <linux/mfd/lochnagar2_regs.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define LN2_MAX_NSAMPLE 1023
+#define LN2_SAMPLE_US 1670
+
+#define LN2_CURR_UNITS 1000
+#define LN2_VOLT_UNITS 1000
+#define LN2_TEMP_UNITS 1000
+#define LN2_PWR_UNITS 1000000
+
+static const char * const lochnagar_chan_names[] = {
+ "DBVDD1",
+ "1V8 DSP",
+ "1V8 CDC",
+ "VDDCORE DSP",
+ "AVDD 1V8",
+ "SYSVDD",
+ "VDDCORE CDC",
+ "MICVDD",
+};
+
+struct lochnagar_hwmon {
+ struct regmap *regmap;
+
+ long power_nsamples[ARRAY_SIZE(lochnagar_chan_names)];
+
+ /* Lock to ensure only a single sensor is read at a time */
+ struct mutex sensor_lock;
+};
+
+enum lochnagar_measure_mode {
+ LN2_CURR = 0,
+ LN2_VOLT,
+ LN2_TEMP,
+};
+
+/**
+ * float_to_long - Convert ieee754 reading from hardware to an integer
+ *
+ * @data: Value read from the hardware
+ * @precision: Units to multiply up to eg. 1000 = milli, 1000000 = micro
+ *
+ * Return: Converted integer reading
+ *
+ * Depending on the measurement type the hardware returns an ieee754
+ * floating point value in either volts, amps or celsius. This function
+ * will convert that into an integer in a smaller unit such as micro-amps
+ * or milli-celsius. The hardware does not return NaN, so consideration of
+ * that is not required.
+ */
+static long float_to_long(u32 data, u32 precision)
+{
+ u64 man = data & 0x007FFFFF;
+ int exp = ((data & 0x7F800000) >> 23) - 127 - 23;
+ bool negative = data & 0x80000000;
+ long result;
+
+ man = (man + (1 << 23)) * precision;
+
+ if (fls64(man) + exp > (int)sizeof(long) * 8 - 1)
+ result = LONG_MAX;
+ else if (exp < 0)
+ result = (man + (1ull << (-exp - 1))) >> -exp;
+ else
+ result = man << exp;
+
+ return negative ? -result : result;
+}
+
+static int do_measurement(struct regmap *regmap, int chan,
+ enum lochnagar_measure_mode mode, int nsamples)
+{
+ unsigned int val;
+ int ret;
+
+ chan = 1 << (chan + LOCHNAGAR2_IMON_MEASURED_CHANNELS_SHIFT);
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL1,
+ LOCHNAGAR2_IMON_ENA_MASK | chan | mode);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL2, nsamples);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
+ LOCHNAGAR2_IMON_CONFIGURE_MASK);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
+ val & LOCHNAGAR2_IMON_DONE_MASK,
+ 1000, 10000);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
+ LOCHNAGAR2_IMON_MEASURE_MASK);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * Actual measurement time is ~1.67mS per sample, approximate this
+ * with a 1.5mS per sample msleep and then poll for success up to
+ * ~0.17mS * 1023 (LN2_MAX_NSAMPLES). Normally for smaller values
+ * of nsamples the poll will complete on the first loop due to
+ * other latency in the system.
+ */
+ msleep((nsamples * 3) / 2);
+
+ ret = regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
+ val & LOCHNAGAR2_IMON_DONE_MASK,
+ 5000, 200000);
+ if (ret < 0)
+ return ret;
+
+ return regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3, 0);
+}
+
+static int request_data(struct regmap *regmap, int chan, u32 *data)
+{
+ unsigned int val;
+ int ret;
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4,
+ LOCHNAGAR2_IMON_DATA_REQ_MASK |
+ chan << LOCHNAGAR2_IMON_CH_SEL_SHIFT);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL4, val,
+ val & LOCHNAGAR2_IMON_DATA_RDY_MASK,
+ 1000, 10000);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA1, &val);
+ if (ret < 0)
+ return ret;
+
+ *data = val << 16;
+
+ ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA2, &val);
+ if (ret < 0)
+ return ret;
+
+ *data |= val;
+
+ return regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4, 0);
+}
+
+static int read_sensor(struct device *dev, int chan,
+ enum lochnagar_measure_mode mode, int nsamples,
+ unsigned int precision, long *val)
+{
+ struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
+ struct regmap *regmap = priv->regmap;
+ u32 data;
+ int ret;
+
+ mutex_lock(&priv->sensor_lock);
+
+ ret = do_measurement(regmap, chan, mode, nsamples);
+ if (ret < 0) {
+ dev_err(dev, "Failed to perform measurement: %d\n", ret);
+ goto error;
+ }
+
+ ret = request_data(regmap, chan, &data);
+ if (ret < 0) {
+ dev_err(dev, "Failed to read measurement: %d\n", ret);
+ goto error;
+ }
+
+ *val = float_to_long(data, precision);
+
+error:
+ mutex_unlock(&priv->sensor_lock);
+
+ return ret;
+}
+
+static int read_power(struct device *dev, int chan, long *val)
+{
+ struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
+ int nsamples = priv->power_nsamples[chan];
+ u64 power;
+ int ret;
+
+ if (!strcmp("SYSVDD", lochnagar_chan_names[chan])) {
+ power = 5 * LN2_PWR_UNITS;
+ } else {
+ ret = read_sensor(dev, chan, LN2_VOLT, 1, LN2_PWR_UNITS, val);
+ if (ret < 0)
+ return ret;
+
+ power = abs(*val);
+ }
+
+ ret = read_sensor(dev, chan, LN2_CURR, nsamples, LN2_PWR_UNITS, val);
+ if (ret < 0)
+ return ret;
+
+ power *= abs(*val);
+ power = DIV_ROUND_CLOSEST_ULL(power, LN2_PWR_UNITS);
+
+ if (power > LONG_MAX)
+ *val = LONG_MAX;
+ else
+ *val = power;
+
+ return 0;
+}
+
+static umode_t lochnagar_is_visible(const void *drvdata,
+ enum hwmon_sensor_types type,
+ u32 attr, int chan)
+{
+ switch (type) {
+ case hwmon_in:
+ if (!strcmp("SYSVDD", lochnagar_chan_names[chan]))
+ return 0;
+ break;
+ case hwmon_power:
+ if (attr == hwmon_power_average_interval)
+ return 0644;
+ break;
+ default:
+ break;
+ }
+
+ return 0444;
+}
+
+static int lochnagar_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int chan, long *val)
+{
+ struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
+ int interval;
+
+ switch (type) {
+ case hwmon_in:
+ return read_sensor(dev, chan, LN2_VOLT, 1, LN2_VOLT_UNITS, val);
+ case hwmon_curr:
+ return read_sensor(dev, chan, LN2_CURR, 1, LN2_CURR_UNITS, val);
+ case hwmon_temp:
+ return read_sensor(dev, chan, LN2_TEMP, 1, LN2_TEMP_UNITS, val);
+ case hwmon_power:
+ switch (attr) {
+ case hwmon_power_average:
+ return read_power(dev, chan, val);
+ case hwmon_power_average_interval:
+ interval = priv->power_nsamples[chan] * LN2_SAMPLE_US;
+ *val = DIV_ROUND_CLOSEST(interval, 1000);
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int lochnagar_read_string(struct device *dev,
+ enum hwmon_sensor_types type, u32 attr,
+ int chan, const char **str)
+{
+ switch (type) {
+ case hwmon_in:
+ case hwmon_curr:
+ case hwmon_power:
+ *str = lochnagar_chan_names[chan];
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int lochnagar_write(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int chan, long val)
+{
+ struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
+
+ if (type != hwmon_power || attr != hwmon_power_average_interval)
+ return -EOPNOTSUPP;
+
+ val = clamp_t(long, val, 1, (LN2_MAX_NSAMPLE * LN2_SAMPLE_US) / 1000);
+ val = DIV_ROUND_CLOSEST(val * 1000, LN2_SAMPLE_US);
+
+ priv->power_nsamples[chan] = val;
+
+ return 0;
+}
+
+static const struct hwmon_ops lochnagar_ops = {
+ .is_visible = lochnagar_is_visible,
+ .read = lochnagar_read,
+ .read_string = lochnagar_read_string,
+ .write = lochnagar_write,
+};
+
+static const struct hwmon_channel_info *lochnagar_info[] = {
+ HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+ HWMON_CHANNEL_INFO(in, HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL),
+ HWMON_CHANNEL_INFO(curr, HWMON_C_INPUT | HWMON_C_LABEL,
+ HWMON_C_INPUT | HWMON_C_LABEL,
+ HWMON_C_INPUT | HWMON_C_LABEL,
+ HWMON_C_INPUT | HWMON_C_LABEL,
+ HWMON_C_INPUT | HWMON_C_LABEL,
+ HWMON_C_INPUT | HWMON_C_LABEL,
+ HWMON_C_INPUT | HWMON_C_LABEL,
+ HWMON_C_INPUT | HWMON_C_LABEL),
+ HWMON_CHANNEL_INFO(power, HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
+ HWMON_P_LABEL,
+ HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
+ HWMON_P_LABEL,
+ HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
+ HWMON_P_LABEL,
+ HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
+ HWMON_P_LABEL,
+ HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
+ HWMON_P_LABEL,
+ HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
+ HWMON_P_LABEL,
+ HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
+ HWMON_P_LABEL,
+ HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
+ HWMON_P_LABEL),
+ NULL
+};
+
+static const struct hwmon_chip_info lochnagar_chip_info = {
+ .ops = &lochnagar_ops,
+ .info = lochnagar_info,
+};
+
+static const struct of_device_id lochnagar_of_match[] = {
+ { .compatible = "cirrus,lochnagar2-hwmon" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, lochnagar_of_match);
+
+static int lochnagar_hwmon_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device *hwmon_dev;
+ struct lochnagar_hwmon *priv;
+ int i;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ mutex_init(&priv->sensor_lock);
+
+ priv->regmap = dev_get_regmap(dev->parent, NULL);
+ if (!priv->regmap) {
+ dev_err(dev, "No register map found\n");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(priv->power_nsamples); i++)
+ priv->power_nsamples[i] = 96;
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev, "Lochnagar", priv,
+ &lochnagar_chip_info,
+ NULL);
+
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static struct platform_driver lochnagar_hwmon_driver = {
+ .driver = {
+ .name = "lochnagar-hwmon",
+ .of_match_table = lochnagar_of_match,
+ },
+ .probe = lochnagar_hwmon_probe,
+};
+module_platform_driver(lochnagar_hwmon_driver);
+
+MODULE_AUTHOR("Lucas Tanure <tanureal@opensource.cirrus.com>");
+MODULE_DESCRIPTION("Lochnagar hardware monitoring features");
+MODULE_LICENSE("GPL");
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