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+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for SQ52205 power monitor chip
+ *
+ * Copyright (C) 2024 Wenliang Yan <wenliang202407@163.com>
+ */
+
+#include "linux/device.h"
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/jiffies.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/delay.h>
+#include <linux/util_macros.h>
+#include <linux/regmap.h>
+
+// #include <linux/platform_data/sq522xx.h>
+
+/* common register definitions */
+#define SQ522XX_CONFIG 0x00
+#define SQ522XX_SHUNT_VOLTAGE 0x01 /* readonly */
+#define SQ522XX_BUS_VOLTAGE 0x02 /* readonly */
+#define SQ522XX_POWER 0x03 /* readonly */
+#define SQ522XX_CURRENT 0x04 /* readonly */
+#define SQ522XX_CALIBRATION 0x05
+
+
+/* SQ52205 register definitions */
+#define SQ52205_MASK_ENABLE 0x06
+#define SQ52205_ALERT_LIMIT 0x07
+#define SQ52205_EIN 0x0A
+#define SQ52205_ACCUM_CONFIG 0x0D
+
+
+/* register count */
+
+#define SQ52205_REGISTERS 0x0D
+
+#define SQ522XX_MAX_REGISTERS 0x0D
+
+/* settings - depend on use case */
+#define SQ52205_CONFIG_DEFAULT 0x4527 /* averages=16 */
+#define SQ52205_ACCUM_CONFIG_DEFAULT 0x044C
+
+/* worst case is 68.10 ms (~14.6Hz) */
+#define SQ522XX_CONVERSION_RATE 15
+#define SQ522XX_MAX_DELAY 69 /* worst case delay in ms */
+
+#define SQ522XX_RSHUNT_DEFAULT 10000 //10mOhms
+#define SQ52205_BUS_VOLTAGE_LSB 1250 //1.25mV
+
+/* bit mask for reading the averaging setting in the configuration register */
+#define SQ52205_AVG_RD_MASK 0x0E00
+
+#define SQ52205_READ_AVG(reg) (((reg) & SQ52205_AVG_RD_MASK) >> 9)
+#define SQ52205_SHIFT_AVG(val) ((val) << 9)
+
+
+
+
+/* common attrs, sq52205 attrs and NULL */
+#define SQ522XX_MAX_ATTRIBUTE_GROUPS 3
+
+/*
+ * Both bus voltage and shunt voltage conversion times for sq52205 are set
+ * to 0b0100 on POR, which translates to 2200 microseconds in total.
+ */
+#define SQ52205_TOTAL_CONV_TIME_DEFAULT 2200
+
+static struct regmap_config sq522xx_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 16,
+};
+
+enum sq522xx_ids { sq52205 };
+
+struct sq522xx_config {
+ u16 config_default;
+ int calibration_factor;
+ int registers;
+ int shunt_div;
+ int bus_voltage_shift;
+ int bus_voltage_lsb; /* uV */
+ int power_lsb; /* uW */
+};
+
+struct sq522xx_data {
+ const struct sq522xx_config *config;
+
+ long rshunt;
+
+ struct mutex config_lock;
+ struct i2c_client *client;
+ struct regmap *regmap;
+
+ const struct attribute_group *groups[SQ522XX_MAX_ATTRIBUTE_GROUPS];
+};
+
+static const struct sq522xx_config sq522xx_config[] = {
+ [sq52205] = {
+ .config_default = SQ52205_CONFIG_DEFAULT,
+ .calibration_factor = 5120000,
+ .registers = SQ52205_REGISTERS,
+ .shunt_div = 400,
+ .bus_voltage_shift = 0,
+ .bus_voltage_lsb = SQ52205_BUS_VOLTAGE_LSB,
+ .power_lsb = 25000,
+ },
+};
+
+/*
+ * Available averaging rates for sq52205. The indices correspond with
+ * the bit values expected by the chip (according to the sq52205 datasheet)
+ */
+static const int sq52205_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
+
+static int sq52205_reg_to_interval(u16 config)
+{
+ int avg = sq52205_avg_tab[SQ52205_READ_AVG(config)];
+
+ /*
+ * Multiply the total conversion time by the number of averages.
+ * Return the result in milliseconds.
+ */
+ return DIV_ROUND_CLOSEST(avg * SQ52205_TOTAL_CONV_TIME_DEFAULT, 1000);
+}
+
+/*
+ * Return the new, shifted AVG field value of CONFIG register,
+ * to use with regmap_update_bits
+ */
+static u16 sq52205_interval_to_reg(int interval)
+{
+ int avg, avg_bits;
+
+ avg = DIV_ROUND_CLOSEST(interval * 1000,
+ SQ52205_TOTAL_CONV_TIME_DEFAULT);
+ avg_bits = find_closest(avg, sq52205_avg_tab,
+ ARRAY_SIZE(sq52205_avg_tab));
+
+ return SQ52205_SHIFT_AVG(avg_bits);
+}
+
+/*
+ * Calibration register is set to the best value, which eliminates
+ * truncation errors on calculating current register in hardware.
+ * According to datasheet the best values are 2048 for
+ * sq52205. They are hardcoded as calibration_value.
+ */
+static int sq522xx_calibrate(struct sq522xx_data *data)
+{
+ u16 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
+ data->rshunt);
+
+ return regmap_write(data->regmap, SQ522XX_CALIBRATION, val);
+}
+
+/*
+ * Initialize the configuration and calibration registers.
+ */
+static int sq522xx_init(struct sq522xx_data *data)
+{
+ int ret = regmap_write(data->regmap, SQ522XX_CONFIG,
+ data->config->config_default);
+ if (ret < 0)
+ return ret;
+ // configure ENABLE register
+ ret = regmap_write(data->regmap, SQ52205_ACCUM_CONFIG,
+ SQ52205_ACCUM_CONFIG_DEFAULT);
+ if (ret < 0)
+ return ret;
+ /*
+ * Set current LSB to 1mA, shunt is in uOhms
+ *
+ */
+ return sq522xx_calibrate(data);
+}
+
+static int sq522xx_read_reg(struct device *dev, int reg, unsigned int *regval)
+{
+ struct sq522xx_data *data = dev_get_drvdata(dev);
+ int ret, retry;
+
+ dev_dbg(dev, "Starting register %d read\n", reg);
+
+ for (retry = 5; retry; retry--) {
+
+ ret = regmap_read(data->regmap, reg, regval);
+ if (ret < 0)
+ return ret;
+
+ dev_dbg(dev, "read %d, val = 0x%04x\n", reg, *regval);
+
+ /*
+ * If the current value in the calibration register is 0, the
+ * power and current registers will also remain at 0. In case
+ * the chip has been reset let's check the calibration
+ * register and reinitialize if needed.
+ * We do that extra read of the calibration register if there
+ * is some hint of a chip reset.
+ */
+ if (*regval == 0) {
+ unsigned int cal;
+
+ ret = regmap_read(data->regmap, SQ522XX_CALIBRATION,
+ &cal);
+ if (ret < 0)
+ return ret;
+
+ if (cal == 0) {
+ dev_warn(dev, "chip not calibrated\n");
+
+ ret = sq522xx_init(data);
+ if (ret < 0)
+ return ret;
+ /*
+ * Let's make sure the power and current
+ * registers have been updated before trying
+ * again.
+ */
+ msleep(SQ522XX_MAX_DELAY);
+ continue;
+ }
+ }
+ return 0;
+ }
+
+ /*
+ * If we're here then although all write operations succeeded, the
+ * chip still returns 0 in the calibration register. Nothing more we
+ * can do here.
+ */
+ dev_err(dev, "unable to reinitialize the chip\n");
+ return -ENODEV;
+}
+
+static int sq522xx_get_value(struct sq522xx_data *data, u8 reg,
+ unsigned int regval)
+{
+ int val;
+
+ switch (reg) {
+ case SQ522XX_SHUNT_VOLTAGE:
+ /* signed register , value is in mV*/
+ val = DIV_ROUND_CLOSEST((s16)regval, data->config->shunt_div);
+ break;
+ case SQ522XX_BUS_VOLTAGE:
+ /* signed register , value is in mV*/
+ val = (regval >> data->config->bus_voltage_shift)
+ * data->config->bus_voltage_lsb;
+ val = DIV_ROUND_CLOSEST(val, 1000);
+ break;
+ case SQ522XX_POWER:
+ /* value is in uV*/
+ val = regval * data->config->power_lsb;
+ break;
+ case SQ522XX_CURRENT:
+ /* signed register, LSB=1mA (selected), in mA */
+ val = (s16)regval;
+ break;
+ case SQ522XX_CALIBRATION:
+ val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
+ regval);
+ break;
+ default:
+ /* programmer goofed */
+ WARN_ON_ONCE(1);
+ val = 0;
+ break;
+ }
+
+ return val;
+}
+
+static ssize_t sq522xx_show_value(struct device *dev,
+ struct device_attribute *da, char *buf)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ struct sq522xx_data *data = dev_get_drvdata(dev);
+ unsigned int regval;
+
+ int err = sq522xx_read_reg(dev, attr->index, ®val);
+
+ if (err < 0)
+ return err;
+
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ sq522xx_get_value(data, attr->index, regval));
+}
+
+/*
+ * In order to keep calibration register value fixed, the product
+ * of current_lsb and shunt_resistor should also be fixed and equal
+ * to shunt_voltage_lsb = 1 / shunt_div multiplied by 10^9 in order
+ * to keep the scale.
+ */
+static ssize_t sq522xx_set_shunt(struct device *dev,
+ struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ unsigned long val;
+ int status;
+ struct sq522xx_data *data = dev_get_drvdata(dev);
+
+ status = kstrtoul(buf, 10, &val);
+ if (status < 0)
+ return status;
+
+ if (val == 0 ||
+ /* Values greater than the calibration factor make no sense. */
+ val > data->config->calibration_factor)
+ return -EINVAL;
+
+ mutex_lock(&data->config_lock);
+ data->rshunt = val;
+
+ status = sq522xx_calibrate(data);
+ mutex_unlock(&data->config_lock);
+ if (status < 0)
+ return status;
+
+ return count;
+}
+
+static ssize_t sq522xx_show_shunt(struct device *dev,
+ struct device_attribute *da,
+ char *buf)
+{
+ struct sq522xx_data *data = dev_get_drvdata(dev);
+
+ return snprintf(buf, PAGE_SIZE, "%li\n", data->rshunt);
+}
+
+
+
+static ssize_t sq52205_set_interval(struct device *dev,
+ struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ struct sq522xx_data *data = dev_get_drvdata(dev);
+ unsigned long val;
+ int status;
+
+ status = kstrtoul(buf, 10, &val);
+ if (status < 0)
+ return status;
+
+ if (val > INT_MAX || val == 0)
+ return -EINVAL;
+
+ status = regmap_update_bits(data->regmap, SQ522XX_CONFIG,
+ SQ52205_AVG_RD_MASK,
+ sq52205_interval_to_reg(val));
+ if (status < 0)
+ return status;
+
+ return count;
+}
+
+static ssize_t sq52205_show_interval(struct device *dev,
+ struct device_attribute *da, char *buf)
+{
+ struct sq522xx_data *data = dev_get_drvdata(dev);
+ int status;
+ unsigned int regval;
+
+ status = regmap_read(data->regmap, SQ522XX_CONFIG, ®val);
+ if (status)
+ return status;
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", sq52205_reg_to_interval(regval));
+}
+
+static int sq52205_read_reg48(const struct i2c_client *client, u8 reg, long *accumulator_24, long *sample_count)
+{
+ u8 data[6];
+ int err;
+ *accumulator_24 = 0;
+ *sample_count = 0;
+
+ /* 48-bit register read */
+ err = i2c_smbus_read_i2c_block_data(client, reg, 6, data);
+ if (err < 0)
+ return err;
+ if (err != 6)
+ return -EIO;
+ *accumulator_24 = ((data[3] << 16) |
+ (data[4] << 8) |
+ data[5]);
+ *sample_count = ((data[0] << 16) |
+ (data[1] << 8) |
+ data[2]);
+
+ return 0;
+}
+
+static int sq52205_show_avg_power(struct device *dev,
+ struct device_attribute *da, char *buf)
+{
+ struct sq522xx_data *data = dev_get_drvdata(dev);
+ long sample_count, accumulator_24, regval;
+ int status;
+
+ status = sq52205_read_reg48(data->client, SQ52205_EIN, &accumulator_24, &sample_count);
+ if (status)
+ return status;
+ regval = DIV_ROUND_CLOSEST(accumulator_24, sample_count);
+ regval = regval * data->config->power_lsb;
+
+
+ return snprintf(buf, PAGE_SIZE, "%li\n", regval);
+}
+
+/* shunt voltage */
+static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, sq522xx_show_value, NULL,
+ SQ522XX_SHUNT_VOLTAGE);
+
+/* bus voltage */
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, sq522xx_show_value, NULL,
+ SQ522XX_BUS_VOLTAGE);
+
+/* calculated current */
+static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, sq522xx_show_value, NULL,
+ SQ522XX_CURRENT);
+
+/* calculated power */
+static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, sq522xx_show_value, NULL,
+ SQ522XX_POWER);
+
+/* shunt resistance */
+static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
+ sq522xx_show_shunt, sq522xx_set_shunt,
+ SQ522XX_CALIBRATION);
+
+/* update interval (sq52205 only) */
+static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
+ sq52205_show_interval, sq52205_set_interval, 0);
+
+/* update interval (sq52205 only) */
+static SENSOR_DEVICE_ATTR(calculate_avg_power, S_IRUGO,
+ sq52205_show_avg_power, NULL, 0);
+
+/* pointers to created device attributes */
+static struct attribute *sq522xx_attrs[] = {
+ &sensor_dev_attr_in0_input.dev_attr.attr,
+ &sensor_dev_attr_in1_input.dev_attr.attr,
+ &sensor_dev_attr_curr1_input.dev_attr.attr,
+ &sensor_dev_attr_power1_input.dev_attr.attr,
+ &sensor_dev_attr_shunt_resistor.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group sq522xx_group = {
+ .attrs = sq522xx_attrs,
+};
+
+static struct attribute *sq52205_attrs[] = {
+ &sensor_dev_attr_update_interval.dev_attr.attr,
+ &sensor_dev_attr_calculate_avg_power.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group sq52205_group = {
+ .attrs = sq52205_attrs,
+};
+
+static int sq522xx_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct sq522xx_data *data;
+ struct device *hwmon_dev;
+ u32 val;
+ int ret, group = 0;
+ enum sq522xx_ids chip;
+
+ if (client->dev.of_node)
+ chip = (enum sq522xx_ids)of_device_get_match_data(&client->dev);
+ else
+ chip = id->driver_data;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ /* set the device type */
+ data->client = client;
+ data->config = &sq522xx_config[chip];
+ mutex_init(&data->config_lock);
+
+ if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) {
+ val = SQ522XX_RSHUNT_DEFAULT;
+ }
+ if (val <= 0 || val > data->config->calibration_factor)
+ return -ENODEV;
+
+ data->rshunt = val;
+
+ sq522xx_regmap_config.max_register = data->config->registers;
+
+ data->regmap = devm_regmap_init_i2c(client, &sq522xx_regmap_config);
+ if (IS_ERR(data->regmap)) {
+ dev_err(dev, "failed to allocate register map\n");
+ return PTR_ERR(data->regmap);
+ }
+
+ ret = sq522xx_init(data);
+ if (ret < 0) {
+ dev_err(dev, "error configuring the device: %d\n", ret);
+ return -ENODEV;
+ }
+
+ data->groups[group++] = &sq522xx_group;
+ if (chip == sq52205)
+ data->groups[group++] = &sq52205_group;
+
+ hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
+ data, data->groups);
+ if (IS_ERR(hwmon_dev))
+ return PTR_ERR(hwmon_dev);
+
+ dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
+ client->name, data->rshunt);
+
+ return 0;
+}
+
+static const struct i2c_device_id sq522xx_id[] = {
+ { "sq52205", sq52205 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, sq522xx_id);
+
+static const struct of_device_id sq522xx_of_match[] = {
+ {
+ .compatible = "silergy,sq52205",
+ .data = (void *)sq52205
+ },
+ { },
+};
+MODULE_DEVICE_TABLE(of, sq522xx_of_match);
+
+static struct i2c_driver sq522xx_driver = {
+ .driver = {
+ .name = "sq522xx",
+ .of_match_table = of_match_ptr(sq522xx_of_match),
+ },
+ .probe = sq522xx_probe,
+ .id_table = sq522xx_id,
+};
+
+module_i2c_driver(sq522xx_driver);
+
+MODULE_AUTHOR(" <wenliang202407@163.com> ");
+MODULE_DESCRIPTION("SQ522xx driver");
+MODULE_LICENSE("GPL");