hwmon: Add W83773G driver

Nuvoton W83773G is a hardware monitor IC providing one local
temperature and two remote temperature sensors.

Signed-off-by: Lei YU <mine260309@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

3 files changed, 340 insertions, 0 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 7ad017690e3a..530ff7c9234c 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1725,6 +1725,16 @@ config SENSORS_VT8231
           This driver can also be built as a module.  If so, the module
           will be called vt8231.
 
+config SENSORS_W83773G
+        tristate "Nuvoton W83773G"
+        depends on I2C
+        help
+          If you say yes here you get support for the Nuvoton W83773G hardware
+          monitoring chip.
+
+          This driver can also be built as a module.  If so, the module
+          will be called w83773g.
+
 config SENSORS_W83781D
         tristate "Winbond W83781D, W83782D, W83783S, Asus AS99127F"
         depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 0fe489fab663..f814b4ace138 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_SENSORS_ATK0110)	+= asus_atk0110.o
 # asb100, then w83781d go first, as they can override other drivers' addresses.
 obj-$(CONFIG_SENSORS_ASB100)    += asb100.o
 obj-$(CONFIG_SENSORS_W83627HF)  += w83627hf.o
+obj-$(CONFIG_SENSORS_W83773G)   += w83773g.o
 obj-$(CONFIG_SENSORS_W83792D)   += w83792d.o
 obj-$(CONFIG_SENSORS_W83793)    += w83793.o
 obj-$(CONFIG_SENSORS_W83795)    += w83795.o
diff --git a/drivers/hwmon/w83773g.c b/drivers/hwmon/w83773g.c
new file mode 100644
index 000000000000..0b97c285b049
--- /dev/null
+++ b/drivers/hwmon/w83773g.c
@@ -0,0 +1,329 @@
+/*
+ * Copyright (C) 2017 IBM Corp.
+ *
+ * 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.
+ *
+ * Driver for the Nuvoton W83773G SMBus temperature sensor IC.
+ * Supported models: W83773G
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+
+/* W83773 has 3 channels */
+#define W83773_CHANNELS                         3
+
+/* The W83773 registers */
+#define W83773_CONVERSION_RATE_REG_READ         0x04
+#define W83773_CONVERSION_RATE_REG_WRITE        0x0A
+#define W83773_MANUFACTURER_ID_REG              0xFE
+#define W83773_LOCAL_TEMP                       0x00
+
+static const u8 W83773_STATUS[2] = { 0x02, 0x17 };
+
+static const u8 W83773_TEMP_LSB[2] = { 0x10, 0x25 };
+static const u8 W83773_TEMP_MSB[2] = { 0x01, 0x24 };
+
+static const u8 W83773_OFFSET_LSB[2] = { 0x12, 0x16 };
+static const u8 W83773_OFFSET_MSB[2] = { 0x11, 0x15 };
+
+/* this is the number of sensors in the device */
+static const struct i2c_device_id w83773_id[] = {
+        { "w83773g" },
+        { }
+};
+
+MODULE_DEVICE_TABLE(i2c, w83773_id);
+
+static const struct of_device_id w83773_of_match[] = {
+        {
+                .compatible = "nuvoton,w83773g"
+        },
+        { },
+};
+MODULE_DEVICE_TABLE(of, w83773_of_match);
+
+static inline long temp_of_local(s8 reg)
+{
+        return reg * 1000;
+}
+
+static inline long temp_of_remote(s8 hb, u8 lb)
+{
+        return (hb << 3 | lb >> 5) * 125;
+}
+
+static int get_local_temp(struct regmap *regmap, long *val)
+{
+        unsigned int regval;
+        int ret;
+
+        ret = regmap_read(regmap, W83773_LOCAL_TEMP, &regval);
+        if (ret < 0)
+                return ret;
+
+        *val = temp_of_local(regval);
+        return 0;
+}
+
+static int get_remote_temp(struct regmap *regmap, int index, long *val)
+{
+        unsigned int regval_high;
+        unsigned int regval_low;
+        int ret;
+
+        ret = regmap_read(regmap, W83773_TEMP_MSB[index], &regval_high);
+        if (ret < 0)
+                return ret;
+
+        ret = regmap_read(regmap, W83773_TEMP_LSB[index], &regval_low);
+        if (ret < 0)
+                return ret;
+
+        *val = temp_of_remote(regval_high, regval_low);
+        return 0;
+}
+
+static int get_fault(struct regmap *regmap, int index, long *val)
+{
+        unsigned int regval;
+        int ret;
+
+        ret = regmap_read(regmap, W83773_STATUS[index], &regval);
+        if (ret < 0)
+                return ret;
+
+        *val = (u8)regval & 0x04 >> 2;
+        return 0;
+}
+
+static int get_offset(struct regmap *regmap, int index, long *val)
+{
+        unsigned int regval_high;
+        unsigned int regval_low;
+        int ret;
+
+        ret = regmap_read(regmap, W83773_OFFSET_MSB[index], &regval_high);
+        if (ret < 0)
+                return ret;
+
+        ret = regmap_read(regmap, W83773_OFFSET_LSB[index], &regval_low);
+        if (ret < 0)
+                return ret;
+
+        *val = temp_of_remote(regval_high, regval_low);
+        return 0;
+}
+
+static int set_offset(struct regmap *regmap, int index, long val)
+{
+        int ret;
+        u8 high_byte;
+        u8 low_byte;
+
+        val = clamp_val(val, -127825, 127825);
+        /* offset value equals to (high_byte << 3 | low_byte >> 5) * 125 */
+        val /= 125;
+        high_byte = val >> 3;
+        low_byte = (val & 0x07) << 5;
+
+        ret = regmap_write(regmap, W83773_OFFSET_MSB[index], high_byte);
+        if (ret < 0)
+                return ret;
+
+        return regmap_write(regmap, W83773_OFFSET_LSB[index], low_byte);
+}
+
+static int get_update_interval(struct regmap *regmap, long *val)
+{
+        unsigned int regval;
+        int ret;
+
+        ret = regmap_read(regmap, W83773_CONVERSION_RATE_REG_READ, &regval);
+        if (ret < 0)
+                return ret;
+
+        *val = 16000 >> regval;
+        return 0;
+}
+
+static int set_update_interval(struct regmap *regmap, long val)
+{
+        int rate;
+
+        /*
+         * For valid rates, interval can be calculated as
+         *      interval = (1 << (8 - rate)) * 62.5;
+         * Rounded rate is therefore
+         *      rate = 8 - __fls(interval * 8 / (62.5 * 7));
+         * Use clamp_val() to avoid overflows, and to ensure valid input
+         * for __fls.
+         */
+        val = clamp_val(val, 62, 16000) * 10;
+        rate = 8 - __fls((val * 8 / (625 * 7)));
+        return regmap_write(regmap, W83773_CONVERSION_RATE_REG_WRITE, rate);
+}
+
+static int w83773_read(struct device *dev, enum hwmon_sensor_types type,
+                       u32 attr, int channel, long *val)
+{
+        struct regmap *regmap = dev_get_drvdata(dev);
+
+        if (type == hwmon_chip) {
+                if (attr == hwmon_chip_update_interval)
+                        return get_update_interval(regmap, val);
+                return -EOPNOTSUPP;
+        }
+
+        switch (attr) {
+        case hwmon_temp_input:
+                if (channel == 0)
+                        return get_local_temp(regmap, val);
+                return get_remote_temp(regmap, channel - 1, val);
+        case hwmon_temp_fault:
+                return get_fault(regmap, channel - 1, val);
+        case hwmon_temp_offset:
+                return get_offset(regmap, channel - 1, val);
+        default:
+                return -EOPNOTSUPP;
+        }
+}
+
+static int w83773_write(struct device *dev, enum hwmon_sensor_types type,
+                        u32 attr, int channel, long val)
+{
+        struct regmap *regmap = dev_get_drvdata(dev);
+
+        if (type == hwmon_chip && attr == hwmon_chip_update_interval)
+                return set_update_interval(regmap, val);
+
+        if (type == hwmon_temp && attr == hwmon_temp_offset)
+                return set_offset(regmap, channel - 1, val);
+
+        return -EOPNOTSUPP;
+}
+
+static umode_t w83773_is_visible(const void *data, enum hwmon_sensor_types type,
+                                 u32 attr, int channel)
+{
+        switch (type) {
+        case hwmon_chip:
+                switch (attr) {
+                case hwmon_chip_update_interval:
+                        return 0644;
+                }
+                break;
+        case hwmon_temp:
+                switch (attr) {
+                case hwmon_temp_input:
+                case hwmon_temp_fault:
+                        return 0444;
+                case hwmon_temp_offset:
+                        return 0644;
+                }
+                break;
+        default:
+                break;
+        }
+        return 0;
+}
+
+static const u32 w83773_chip_config[] = {
+        HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
+        0
+};
+
+static const struct hwmon_channel_info w83773_chip = {
+        .type = hwmon_chip,
+        .config = w83773_chip_config,
+};
+
+static const u32 w83773_temp_config[] = {
+        HWMON_T_INPUT,
+        HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_OFFSET,
+        HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_OFFSET,
+        0
+};
+
+static const struct hwmon_channel_info w83773_temp = {
+        .type = hwmon_temp,
+        .config = w83773_temp_config,
+};
+
+static const struct hwmon_channel_info *w83773_info[] = {
+        &w83773_chip,
+        &w83773_temp,
+        NULL
+};
+
+static const struct hwmon_ops w83773_ops = {
+        .is_visible = w83773_is_visible,
+        .read = w83773_read,
+        .write = w83773_write,
+};
+
+static const struct hwmon_chip_info w83773_chip_info = {
+        .ops = &w83773_ops,
+        .info = w83773_info,
+};
+
+static const struct regmap_config w83773_regmap_config = {
+        .reg_bits = 8,
+        .val_bits = 8,
+};
+
+static int w83773_probe(struct i2c_client *client,
+                        const struct i2c_device_id *id)
+{
+        struct device *dev = &client->dev;
+        struct device *hwmon_dev;
+        struct regmap *regmap;
+        int ret;
+
+        regmap = devm_regmap_init_i2c(client, &w83773_regmap_config);
+        if (IS_ERR(regmap)) {
+                dev_err(dev, "failed to allocate register map\n");
+                return PTR_ERR(regmap);
+        }
+
+        /* Set the conversion rate to 2 Hz */
+        ret = regmap_write(regmap, W83773_CONVERSION_RATE_REG_WRITE, 0x05);
+        if (ret < 0) {
+                dev_err(&client->dev, "error writing config rate register\n");
+                return ret;
+        }
+
+        i2c_set_clientdata(client, regmap);
+
+        hwmon_dev = devm_hwmon_device_register_with_info(dev,
+                                                         client->name,
+                                                         regmap,
+                                                         &w83773_chip_info,
+                                                         NULL);
+        return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static struct i2c_driver w83773_driver = {
+        .class = I2C_CLASS_HWMON,
+        .driver = {
+                .name   = "w83773g",
+                .of_match_table = of_match_ptr(w83773_of_match),
+        },
+        .probe = w83773_probe,
+        .id_table = w83773_id,
+};
+
+module_i2c_driver(w83773_driver);
+
+MODULE_AUTHOR("Lei YU <mine260309@gmail.com>");
+MODULE_DESCRIPTION("W83773G temperature sensor driver");
+MODULE_LICENSE("GPL");