Signed-off-by: Pascal Bouwmann<bouwmann@xxxxxxxxxx>
---
diff --git a/drivers/iio/adc/ltc2945_iio.c b/drivers/iio/adc/ltc2945_iio.c
new file mode 100644
index 000000000000..0ede89b6515e
--- /dev/null
+++ b/drivers/iio/adc/ltc2945_iio.c
@@ -0,0 +1,495 @@
+/*
+ * Driver for Linear Technology LTC2945 I2C Power Monitor
+ *
+ * Copyright (c) 2019 tau-tec GmbH
+ * Author: Pascal Bouwmann<bouwmann@xxxxxxxxxx>
+ *
+ *
+ * based on the hwmon ltc2945 driver
+ * Copyright (c) 2014 Guenter Roeck
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/stat.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/regmap.h>
+
+
+/* chip registers */
+#define LTC2945_CONTROL 0x00
+#define LTC2945_ALERT 0x01
+#define LTC2945_STATUS 0x02
+#define LTC2945_FAULT 0x03
+#define LTC2945_POWER_H 0x05
+#define LTC2945_MAX_POWER_H 0x08
+#define LTC2945_MIN_POWER_H 0x0b
+#define LTC2945_MAX_POWER_THRES_H 0x0e
+#define LTC2945_MIN_POWER_THRES_H 0x11
+#define LTC2945_SENSE_H 0x14
+#define LTC2945_MAX_SENSE_H 0x16
+#define LTC2945_MIN_SENSE_H 0x18
+#define LTC2945_MAX_SENSE_THRES_H 0x1a
+#define LTC2945_MIN_SENSE_THRES_H 0x1c
+#define LTC2945_VIN_H 0x1e
+#define LTC2945_MAX_VIN_H 0x20
+#define LTC2945_MIN_VIN_H 0x22
+#define LTC2945_MAX_VIN_THRES_H 0x24
+#define LTC2945_MIN_VIN_THRES_H 0x26
+#define LTC2945_ADIN_H 0x28
+#define LTC2945_MAX_ADIN_H 0x2a
+#define LTC2945_MIN_ADIN_H 0x2c
+#define LTC2945_MAX_ADIN_THRES_H 0x2e
+#define LTC2945_MIN_ADIN_THRES_H 0x30
+#define LTC2945_MIN_ADIN_THRES_L 0x31
+
+/* Fault register bits */
+#define FAULT_ADIN_UV (1 << 0)
+#define FAULT_ADIN_OV (1 << 1)
+#define FAULT_VIN_UV (1 << 2)
+#define FAULT_VIN_OV (1 << 3)
+#define FAULT_SENSE_UV (1 << 4)
+#define FAULT_SENSE_OV (1 << 5)
+#define FAULT_POWER_UV (1 << 6)
+#define FAULT_POWER_OV (1 << 7)
+
+/* Control register bits */
+#define CONTROL_MULT_SELECT (1 << 0)
+#define CONTROL_TEST_MODE (1 << 4)
+
+
+/* Shunt resistor in uOhm */
+#define DEFAULT_SHUNT_RESISTOR 1000
+
+
+struct ltc2945_data
+{
+ int device_id;
+ void *client;
+ struct device *dev;
+ struct regmap *regmap;
+ unsigned int shunt_resistor;
+ struct mutex lock;
+};
+
+static inline bool is_power_reg(u8 reg)
+{
+ return (reg < LTC2945_SENSE_H);
+}
+
+/* Return the value of the given register in uW, mV, or mA */
+static long long ltc2945_reg_to_val(struct iio_dev *indio_dev, u8 reg)
+{
+ unsigned int control;
+ u8 buf[3];
+ long long val;
+ int ret;
+ struct ltc2945_data *data = iio_priv(indio_dev);
+
+ ret = regmap_bulk_read(data->regmap, reg, buf,
+ is_power_reg(reg) ? 3 : 2);
+
+ if (ret < 0)
+ return (ret);
+
+ if (is_power_reg(reg))
+ /* power */
+ val = (buf[0] << 16) + (buf[1] << 8) + buf[2];
+ else
+ /* current, voltage */
+ val = (buf[0] << 4) + (buf[1] >> 4);
+
+ switch (reg) {
+ case LTC2945_POWER_H:
+ case LTC2945_MAX_POWER_H:
+ case LTC2945_MIN_POWER_H:
+ case LTC2945_MAX_POWER_THRES_H:
+ case LTC2945_MIN_POWER_THRES_H:
+ /*
+ * Convert to uW by assuming current is measured with
+ * an 1mOhm sense resistor, similar to current
+ * measurements.
+ * Control register bit 0 selects if voltage at SENSE+/VDD
+ * or voltage at ADIN is used to measure power.
+ */
+ ret = regmap_read(data->regmap, LTC2945_CONTROL, &control);
+
+ if (ret < 0)
+ return (ret);
+
+ if (control & CONTROL_MULT_SELECT)
+ /* 25 mV * 25 uV = 0.625 uV resolution. */
+ val *= 625LL;
+ else
+ /* 0.5 mV * 25 uV = 0.0125 uV resolution. */
+ val = (val * 25LL) >> 1;
+
+ /* val has to be divided by the square of the shunt resistor in mOhm */
+ val = div_u64(val, (data->shunt_resistor / 1000)^2);
+ break;
+
+ case LTC2945_VIN_H:
+ case LTC2945_MAX_VIN_H:
+ case LTC2945_MIN_VIN_H:
+ case LTC2945_MAX_VIN_THRES_H:
+ case LTC2945_MIN_VIN_THRES_H:
+ /* 25 mV resolution. Convert to mV. */
+ val *= 25;
+ break;
+
+ case LTC2945_ADIN_H:
+ case LTC2945_MAX_ADIN_H:
+ case LTC2945_MIN_ADIN_THRES_H:
+ case LTC2945_MAX_ADIN_THRES_H:
+ case LTC2945_MIN_ADIN_H:
+ /* 0.5mV resolution. Convert to mV. */
+ val = val >> 1;
+ break;
+
+ case LTC2945_SENSE_H:
+ case LTC2945_MAX_SENSE_H:
+ case LTC2945_MIN_SENSE_H:
+ case LTC2945_MAX_SENSE_THRES_H:
+ case LTC2945_MIN_SENSE_THRES_H:
+ /*
+ * 25 uV resolution. Convert to current as measured with
+ * an 1 mOhm sense resistor, in mA. If a different sense
+ * resistor is installed, calculate the actual current by
+ * dividing the reported current by the sense resistor value
+ * in mOhm.
+ */
+ val *= 25;
+ /* val has to be divided by the shunt resistor in mOhm */
+ val = div_u64(val, data->shunt_resistor / 1000);
+ break;
+
+ default:
+ return (-EINVAL);
+ }
+
+ return (val);
+} /* static long long ltc2945_reg_to_val */
+
+static int ltc2945_val_to_reg(struct iio_dev *indio_dev, u8 reg,
+ unsigned long val)
+{
+ unsigned int control;
+ int ret;
+ struct ltc2945_data *data = iio_priv(indio_dev);
+
+ switch (reg) {
+ case LTC2945_POWER_H:
+ case LTC2945_MAX_POWER_H:
+ case LTC2945_MIN_POWER_H:
+ case LTC2945_MAX_POWER_THRES_H:
+ case LTC2945_MIN_POWER_THRES_H:
+ /*
+ * Convert to register value by assuming current is measured
+ * with an 1mOhm sense resistor, similar to current
+ * measurements.
+ * Control register bit 0 selects if voltage at SENSE+/VDD
+ * or voltage at ADIN is used to measure power, which in turn
+ * determines register calculations.
+ */
+ ret = regmap_read(data->regmap, LTC2945_CONTROL, &control);
+
+ if (ret < 0)
+ return (ret);
+
+ if (control & CONTROL_MULT_SELECT)
+ /* 25 mV * 25 uV = 0.625 uV resolution. */
+ val = DIV_ROUND_CLOSEST(val, 625);
+ else
+ /*
+ * 0.5 mV * 25 uV = 0.0125 uV resolution.
+ * Divide first to avoid overflow;
+ * accept loss of accuracy.
+ */
+ val = DIV_ROUND_CLOSEST(val, 25) * 2;
+
+ /* val has to be divided by the square of the shunt resistor in mOhm */
+ val = div_u64(val, (data->shunt_resistor / 1000)^2);
+ break;
+
+ case LTC2945_VIN_H:
+ case LTC2945_MAX_VIN_H:
+ case LTC2945_MIN_VIN_H:
+ case LTC2945_MAX_VIN_THRES_H:
+ case LTC2945_MIN_VIN_THRES_H:
+ /* 25 mV resolution. */
+ val /= 25;
+ break;
+
+ case LTC2945_ADIN_H:
+ case LTC2945_MAX_ADIN_H:
+ case LTC2945_MIN_ADIN_THRES_H:
+ case LTC2945_MAX_ADIN_THRES_H:
+ case LTC2945_MIN_ADIN_H:
+ /* 0.5mV resolution. */
+ val *= 2;
+ break;
+
+ case LTC2945_SENSE_H:
+ case LTC2945_MAX_SENSE_H:
+ case LTC2945_MIN_SENSE_H:
+ case LTC2945_MAX_SENSE_THRES_H:
+ case LTC2945_MIN_SENSE_THRES_H:
+ /*
+ * 25 uV resolution. Convert to current as measured with
+ * an 1 mOhm sense resistor, in mA. If a different sense
+ * resistor is installed, calculate the actual current by
+ * dividing the reported current by the sense resistor value
+ * in mOhm.
+ */
+ val = DIV_ROUND_CLOSEST(val, 25);
+ /* val has to be divided by the shunt resistor in mOhm */
+ val = div_u64(val, (data->shunt_resistor / 1000)^2);
+ break;
+
+ default:
+ return (-EINVAL);
+ }
+
+ return (val);
+
+} /* static int ltc2945_val_to_reg */
+
+static ssize_t ltc2945_show_value(struct iio_dev *indio_dev,
+ u8 reg)
+{
+ long long value;
+ value = ltc2945_reg_to_val(indio_dev, reg);
+ return (value);
+} /* static ssize_t ltc2945_show_value */
+
+static int ltc2945_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ switch (chan->channel) {
+ case 1:
+ *val = ltc2945_show_value(indio_dev, LTC2945_VIN_H);
+
+ if (*val < 0)
+ return ( -EINVAL );
+
+ break;
+
+ case 2:
+ *val = ltc2945_show_value(indio_dev, LTC2945_ADIN_H);
+
+ if (*val < 0)
+ return ( -EINVAL );
+
+ break;
+
+ default:
+ return (-EINVAL);
+ }
+
+ return ( IIO_VAL_INT );
+
+ case IIO_CURRENT:
+ *val = ltc2945_show_value(indio_dev, LTC2945_SENSE_H);
+
+ if (*val < 0)
+ return (-EINVAL);
+
+ return (IIO_VAL_INT);
+
+ case IIO_POWER:
+ *val = ltc2945_show_value(indio_dev, LTC2945_POWER_H);
+
+ if (*val < 0)
+ return (-EINVAL);
+
+ return (IIO_VAL_INT);
+
+ default:
+ return (-EINVAL);
+ }
+
+ return (-EINVAL);
+
+} /* static int ltc2945_read_raw */
+
+/* set the value of the shunt resistor in uOhm */
+static int set_shunt_resistor(struct ltc2945_data *chip, unsigned int val)
+{
+ chip->shunt_resistor = val;
+ return (0);
+} /* static int set_shunt_resistor */
+
+static ssize_t ltc2945_shunt_resistor_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct ltc2945_data *chip = iio_priv(dev_to_iio_dev(dev));
+ return sprintf(buf, "%d\n", chip->shunt_resistor);
+} /* static ssize_t ltc2945_shunt_resistor_show */
+
+static ssize_t ltc2945_shunt_resistor_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct ltc2945_data *chip = iio_priv(dev_to_iio_dev(dev));
+ unsigned long val;
+ int ret;
+
+ ret = kstrtoul((const char *) buf, 10, &val);
+
+ if (ret)
+ return (ret);
+
+ ret = set_shunt_resistor(chip, val);
+
+ if (ret)
+ return (ret);
+
+ return (len);
+} /* static ssize_t ltc2945_shunt_resistor_store */
+
+#define LTC2945_CHAN_RAW(_type, _index, _address) { \
+ .type = (_type), \
+ .address = (_address), \
+ .indexed = 1, \
+ .channel = (_index), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+}
+
+#define LTC2945_CHAN_PROCESSED(_type, _index, _address) { \
+ .type = (_type), \
+ .address = (_address), \
+ .indexed = 1, \
+ .channel = (_index), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
+}
+
+static const struct iio_chan_spec ltc2945_channels[] = {
+ LTC2945_CHAN_PROCESSED(IIO_VOLTAGE, 1, LTC2945_VIN_H),
+ LTC2945_CHAN_PROCESSED(IIO_VOLTAGE, 2, LTC2945_ADIN_H),
+ LTC2945_CHAN_PROCESSED(IIO_POWER, 1, LTC2945_POWER_H),
+ LTC2945_CHAN_PROCESSED(IIO_CURRENT, 1, LTC2945_SENSE_H),
+};
+
+
+static IIO_DEVICE_ATTR(
+ in_shunt_resistor,
+ S_IRUGO | S_IWUSR,
+ ltc2945_shunt_resistor_show,
+ ltc2945_shunt_resistor_store,
+ 0
+);
+
+static struct attribute *ltc2945_attributes[] = {
+ &iio_dev_attr_in_shunt_resistor.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group ltc2945_attribute_group = {
+ .attrs = ltc2945_attributes,
+};
+
+
+static const struct regmap_config ltc2945_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = LTC2945_MIN_ADIN_THRES_L,
+};
+
+
+static const struct iio_info ltc2945_info = {
+ .read_raw = <c2945_read_raw,
+ .attrs = <c2945_attribute_group,
+};
+
+
+static int ltc2945_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int ret;
+ struct ltc2945_data *dev_data;
+ struct iio_dev *indio_dev;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
+ I2C_FUNC_SMBUS_WRITE_BYTE |
+ I2C_FUNC_SMBUS_READ_I2C_BLOCK))
+ return -EOPNOTSUPP;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
+
+ if (!indio_dev)
+ return -ENOMEM;
+
+ dev_data = iio_priv(indio_dev);
+
+ dev_data->client = client;
+ mutex_init(&dev_data->lock);
+
+ dev_data->regmap = devm_regmap_init_i2c(client, <c2945_regmap_config);
+
+ if (IS_ERR(dev_data->regmap))
+ return (PTR_ERR(dev_data->regmap));
+
+ ret = set_shunt_resistor(dev_data, DEFAULT_SHUNT_RESISTOR);
+
+ if (ret)
+ return (ret);
+
+ /* Clear faults */
+ regmap_write(dev_data->regmap, LTC2945_FAULT, 0x00);
+
+ indio_dev->info = <c2945_info;
+ indio_dev->name = id->name;
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = ltc2945_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ltc2945_channels);
+
+ /* This is only used for device removal purposes. */
+ i2c_set_clientdata(client, indio_dev);
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+} /* static int ltc2945_probe */
+
+
+static const struct i2c_device_id ltc2945_id[] = {
+ {"ltc2945_iio", 0},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, ltc2945_id);
+
+
+static struct i2c_driver ltc2945_driver = {
+ .probe = ltc2945_probe,
+ .id_table = ltc2945_id,
+ .driver = {
+ .name = "ltc2945_iio",
+ },
+};
+
+module_i2c_driver(ltc2945_driver);
+
+
+MODULE_AUTHOR("Pascal Bouwmann<bouwmann@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Linear Technology LTC2945 driver");
+MODULE_LICENSE("GPL");
