--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for MAX31730 3-Channel Remote Temperature Sensor
+ *
+ * Copyright (c) 2019 Guenter Roeck <linux@roeck-us.net>
+ */
+
+#include <linux/bits.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/hwmon.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+
+/* Addresses scanned */
+static const unsigned short normal_i2c[] = { 0x1c, 0x1d, 0x1e, 0x1f, 0x4c,
+ 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
+
+/* The MAX31730 registers */
+#define MAX31730_REG_TEMP 0x00
+#define MAX31730_REG_CONF 0x13
+#define MAX31730_STOP BIT(7)
+#define MAX31730_EXTRANGE BIT(1)
+#define MAX31730_REG_TEMP_OFFSET 0x16
+#define MAX31730_TEMP_OFFSET_BASELINE 0x77
+#define MAX31730_REG_OFFSET_ENABLE 0x17
+#define MAX31730_REG_TEMP_MAX 0x20
+#define MAX31730_REG_TEMP_MIN 0x30
+#define MAX31730_REG_STATUS_HIGH 0x32
+#define MAX31730_REG_STATUS_LOW 0x33
+#define MAX31730_REG_CHANNEL_ENABLE 0x35
+#define MAX31730_REG_TEMP_FAULT 0x36
+
+#define MAX31730_REG_MFG_ID 0x50
+#define MAX31730_MFG_ID 0x4d
+#define MAX31730_REG_MFG_REV 0x51
+#define MAX31730_MFG_REV 0x01
+
+#define MAX31730_TEMP_MIN (-128000)
+#define MAX31730_TEMP_MAX 127937
+
+/* Each client has this additional data */
+struct max31730_data {
+ struct i2c_client *client;
+ u8 orig_conf;
+ u8 current_conf;
+ u8 offset_enable;
+ u8 channel_enable;
+};
+
+/*-----------------------------------------------------------------------*/
+
+static inline long max31730_reg_to_mc(s16 temp)
+{
+ return DIV_ROUND_CLOSEST((temp >> 4) * 1000, 16);
+}
+
+static int max31730_write_config(struct max31730_data *data, u8 set_mask,
+ u8 clr_mask)
+{
+ u8 value;
+
+ clr_mask |= MAX31730_EXTRANGE;
+ value = data->current_conf & ~clr_mask;
+ value |= set_mask;
+
+ if (data->current_conf != value) {
+ s32 err;
+
+ err = i2c_smbus_write_byte_data(data->client, MAX31730_REG_CONF,
+ value);
+ if (err)
+ return err;
+ data->current_conf = value;
+ }
+ return 0;
+}
+
+static int max31730_set_enable(struct i2c_client *client, int reg,
+ u8 *confdata, int channel, bool enable)
+{
+ u8 regval = *confdata;
+ int err;
+
+ if (enable)
+ regval |= BIT(channel);
+ else
+ regval &= ~BIT(channel);
+
+ if (regval != *confdata) {
+ err = i2c_smbus_write_byte_data(client, reg, regval);
+ if (err)
+ return err;
+ *confdata = regval;
+ }
+ return 0;
+}
+
+static int max31730_set_offset_enable(struct max31730_data *data, int channel,
+ bool enable)
+{
+ return max31730_set_enable(data->client, MAX31730_REG_OFFSET_ENABLE,
+ &data->offset_enable, channel, enable);
+}
+
+static int max31730_set_channel_enable(struct max31730_data *data, int channel,
+ bool enable)
+{
+ return max31730_set_enable(data->client, MAX31730_REG_CHANNEL_ENABLE,
+ &data->channel_enable, channel, enable);
+}
+
+static int max31730_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct max31730_data *data = dev_get_drvdata(dev);
+ int regval, reg, offset;
+
+ if (type != hwmon_temp)
+ return -EINVAL;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ if (!(data->channel_enable & BIT(channel)))
+ return -ENODATA;
+ reg = MAX31730_REG_TEMP + (channel * 2);
+ break;
+ case hwmon_temp_max:
+ reg = MAX31730_REG_TEMP_MAX + (channel * 2);
+ break;
+ case hwmon_temp_min:
+ reg = MAX31730_REG_TEMP_MIN;
+ break;
+ case hwmon_temp_enable:
+ *val = !!(data->channel_enable & BIT(channel));
+ return 0;
+ case hwmon_temp_offset:
+ if (!channel)
+ return -EINVAL;
+ if (!(data->offset_enable & BIT(channel))) {
+ *val = 0;
+ return 0;
+ }
+ offset = i2c_smbus_read_byte_data(data->client,
+ MAX31730_REG_TEMP_OFFSET);
+ if (offset < 0)
+ return offset;
+ *val = (offset - MAX31730_TEMP_OFFSET_BASELINE) * 125;
+ return 0;
+ case hwmon_temp_fault:
+ regval = i2c_smbus_read_byte_data(data->client,
+ MAX31730_REG_TEMP_FAULT);
+ if (regval < 0)
+ return regval;
+ *val = !!(regval & BIT(channel));
+ return 0;
+ case hwmon_temp_min_alarm:
+ regval = i2c_smbus_read_byte_data(data->client,
+ MAX31730_REG_STATUS_LOW);
+ if (regval < 0)
+ return regval;
+ *val = !!(regval & BIT(channel));
+ return 0;
+ case hwmon_temp_max_alarm:
+ regval = i2c_smbus_read_byte_data(data->client,
+ MAX31730_REG_STATUS_HIGH);
+ if (regval < 0)
+ return regval;
+ *val = !!(regval & BIT(channel));
+ return 0;
+ default:
+ return -EINVAL;
+ }
+ regval = i2c_smbus_read_word_swapped(data->client, reg);
+ if (regval < 0)
+ return regval;
+
+ *val = max31730_reg_to_mc(regval);
+
+ return 0;
+}
+
+static int max31730_write(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long val)
+{
+ struct max31730_data *data = dev_get_drvdata(dev);
+ int reg, err;
+
+ if (type != hwmon_temp)
+ return -EINVAL;
+
+ switch (attr) {
+ case hwmon_temp_max:
+ reg = MAX31730_REG_TEMP_MAX + channel * 2;
+ break;
+ case hwmon_temp_min:
+ reg = MAX31730_REG_TEMP_MIN;
+ break;
+ case hwmon_temp_enable:
+ if (val != 0 && val != 1)
+ return -EINVAL;
+ return max31730_set_channel_enable(data, channel, val);
+ case hwmon_temp_offset:
+ val = clamp_val(val, -14875, 17000) + 14875;
+ val = DIV_ROUND_CLOSEST(val, 125);
+ err = max31730_set_offset_enable(data, channel,
+ val != MAX31730_TEMP_OFFSET_BASELINE);
+ if (err)
+ return err;
+ return i2c_smbus_write_byte_data(data->client,
+ MAX31730_REG_TEMP_OFFSET, val);
+ default:
+ return -EINVAL;
+ }
+
+ val = clamp_val(val, MAX31730_TEMP_MIN, MAX31730_TEMP_MAX);
+ val = DIV_ROUND_CLOSEST(val << 4, 1000) << 4;
+
+ return i2c_smbus_write_word_swapped(data->client, reg, (u16)val);
+}
+
+static umode_t max31730_is_visible(const void *data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ switch (type) {
+ case hwmon_temp:
+ switch (attr) {
+ case hwmon_temp_input:
+ case hwmon_temp_min_alarm:
+ case hwmon_temp_max_alarm:
+ case hwmon_temp_fault:
+ return 0444;
+ case hwmon_temp_min:
+ return channel ? 0444 : 0644;
+ case hwmon_temp_offset:
+ case hwmon_temp_enable:
+ case hwmon_temp_max:
+ return 0644;
+ }
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+static const struct hwmon_channel_info *max31730_info[] = {
+ HWMON_CHANNEL_INFO(chip,
+ HWMON_C_REGISTER_TZ),
+ HWMON_CHANNEL_INFO(temp,
+ HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
+ HWMON_T_ENABLE |
+ HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM,
+ HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
+ HWMON_T_OFFSET | HWMON_T_ENABLE |
+ HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
+ HWMON_T_FAULT,
+ HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
+ HWMON_T_OFFSET | HWMON_T_ENABLE |
+ HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
+ HWMON_T_FAULT,
+ HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
+ HWMON_T_OFFSET | HWMON_T_ENABLE |
+ HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
+ HWMON_T_FAULT
+ ),
+ NULL
+};
+
+static const struct hwmon_ops max31730_hwmon_ops = {
+ .is_visible = max31730_is_visible,
+ .read = max31730_read,
+ .write = max31730_write,
+};
+
+static const struct hwmon_chip_info max31730_chip_info = {
+ .ops = &max31730_hwmon_ops,
+ .info = max31730_info,
+};
+
+static void max31730_remove(void *data)
+{
+ struct max31730_data *max31730 = data;
+ struct i2c_client *client = max31730->client;
+
+ i2c_smbus_write_byte_data(client, MAX31730_REG_CONF,
+ max31730->orig_conf);
+}
+
+static int
+max31730_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct device *hwmon_dev;
+ struct max31730_data *data;
+ int status, err;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
+ return -EIO;
+
+ data = devm_kzalloc(dev, sizeof(struct max31730_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->client = client;
+
+ /* Cache original configuration and enable status */
+ status = i2c_smbus_read_byte_data(client, MAX31730_REG_CHANNEL_ENABLE);
+ if (status < 0)
+ return status;
+ data->channel_enable = status;
+
+ status = i2c_smbus_read_byte_data(client, MAX31730_REG_OFFSET_ENABLE);
+ if (status < 0)
+ return status;
+ data->offset_enable = status;
+
+ status = i2c_smbus_read_byte_data(client, MAX31730_REG_CONF);
+ if (status < 0)
+ return status;
+ data->orig_conf = status;
+ data->current_conf = status;
+
+ err = max31730_write_config(data,
+ data->channel_enable ? 0 : MAX31730_STOP,
+ data->channel_enable ? MAX31730_STOP : 0);
+ if (err)
+ return err;
+
+ dev_set_drvdata(dev, data);
+
+ err = devm_add_action_or_reset(dev, max31730_remove, data);
+ if (err)
+ return err;
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
+ data,
+ &max31730_chip_info,
+ NULL);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id max31730_ids[] = {
+ { "max31730", 0, },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, max31730_ids);
+
+static const struct of_device_id __maybe_unused max31730_of_match[] = {
+ {
+ .compatible = "maxim,max31730",
+ },
+ { },
+};
+MODULE_DEVICE_TABLE(of, max31730_of_match);
+
+static bool max31730_check_reg_temp(struct i2c_client *client,
+ int reg)
+{
+ int regval;
+
+ regval = i2c_smbus_read_byte_data(client, reg + 1);
+ return regval < 0 || (regval & 0x0f);
+}
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int max31730_detect(struct i2c_client *client,
+ struct i2c_board_info *info)
+{
+ struct i2c_adapter *adapter = client->adapter;
+ int regval;
+ int i;
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+ I2C_FUNC_SMBUS_WORD_DATA))
+ return -ENODEV;
+
+ regval = i2c_smbus_read_byte_data(client, MAX31730_REG_MFG_ID);
+ if (regval != MAX31730_MFG_ID)
+ return -ENODEV;
+ regval = i2c_smbus_read_byte_data(client, MAX31730_REG_MFG_REV);
+ if (regval != MAX31730_MFG_REV)
+ return -ENODEV;
+
+ /* lower 4 bit of temperature and limit registers must be 0 */
+ if (max31730_check_reg_temp(client, MAX31730_REG_TEMP_MIN))
+ return -ENODEV;
+
+ for (i = 0; i < 4; i++) {
+ if (max31730_check_reg_temp(client, MAX31730_REG_TEMP + i * 2))
+ return -ENODEV;
+ if (max31730_check_reg_temp(client,
+ MAX31730_REG_TEMP_MAX + i * 2))
+ return -ENODEV;
+ }
+
+ strlcpy(info->type, "max31730", I2C_NAME_SIZE);
+
+ return 0;
+}
+
+static int __maybe_unused max31730_suspend(struct device *dev)
+{
+ struct max31730_data *data = dev_get_drvdata(dev);
+
+ return max31730_write_config(data, MAX31730_STOP, 0);
+}
+
+static int __maybe_unused max31730_resume(struct device *dev)
+{
+ struct max31730_data *data = dev_get_drvdata(dev);
+
+ return max31730_write_config(data, 0, MAX31730_STOP);
+}
+
+static SIMPLE_DEV_PM_OPS(max31730_pm_ops, max31730_suspend, max31730_resume);
+
+static struct i2c_driver max31730_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = "max31730",
+ .of_match_table = of_match_ptr(max31730_of_match),
+ .pm = &max31730_pm_ops,
+ },
+ .probe = max31730_probe,
+ .id_table = max31730_ids,
+ .detect = max31730_detect,
+ .address_list = normal_i2c,
+};
+
+module_i2c_driver(max31730_driver);
+
+MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
+MODULE_DESCRIPTION("MAX31730 driver");
+MODULE_LICENSE("GPL");
projects / users / griffoul / linux.git / commitdiff