hwmon: (tmp102) Convert to use regmap, and drop local cache

By converting the driver to regmap, we can use regmap to cache non-volatile
registers. Stop caching the temperature register; while potentially reading
it more often can result in reading it more often than necessary, this is
offset by the gain due to not re-reading the limit registers.

A positive side effect of this change is that limit registers can now be
read and updated before the first temperature conversion is complete.

Acked-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index f271353..e72cd3d 100644 (file)
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1561,6 +1561,7 @@ config SENSORS_TMP102
        tristate "Texas Instruments TMP102"
        depends on I2C
        depends on THERMAL || !THERMAL_OF
+       select REGMAP_I2C
        help
          If you say yes here you get support for Texas Instruments TMP102
          sensor chips.

diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c
index 82a8a29..a942a25 100644 (file)
--- a/drivers/hwmon/tmp102.c
+++ b/drivers/hwmon/tmp102.c
@@ -24,6 +24,7 @@
 #include <linux/mutex.h>
 #include <linux/device.h>
 #include <linux/jiffies.h>
+#include <linux/regmap.h>
 #include <linux/thermal.h>
 #include <linux/of.h>
 
@@ -61,13 +62,9 @@
 #define CONVERSION_TIME_MS             35      /* in milli-seconds */
 
 struct tmp102 {
-       struct i2c_client *client;
-       struct mutex lock;
+       struct regmap *regmap;
        u16 config_orig;
-       unsigned long last_update;
        unsigned long ready_time;
-       bool valid;
-       int temp[3];
 };
 
 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
@@ -82,45 +79,22 @@ static inline u16 tmp102_mC_to_reg(int val)
        return (val * 128) / 1000;
 }
 
-static const u8 tmp102_reg[] = {
-       TMP102_TEMP_REG,
-       TMP102_TLOW_REG,
-       TMP102_THIGH_REG,
-};
-
-static void tmp102_update_device(struct device *dev)
-{
-       struct tmp102 *tmp102 = dev_get_drvdata(dev);
-       struct i2c_client *client = tmp102->client;
-
-       mutex_lock(&tmp102->lock);
-       if (!tmp102->valid ||
-           time_after(jiffies, tmp102->last_update + HZ / 3)) {
-               int i;
-               for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
-                       int status = i2c_smbus_read_word_swapped(client,
-                                                                tmp102_reg[i]);
-                       if (status > -1)
-                               tmp102->temp[i] = tmp102_reg_to_mC(status);
-               }
-               tmp102->last_update = jiffies;
-               tmp102->valid = true;
-       }
-       mutex_unlock(&tmp102->lock);
-}
-
 static int tmp102_read_temp(void *dev, int *temp)
 {
        struct tmp102 *tmp102 = dev_get_drvdata(dev);
+       unsigned int reg;
+       int ret;
 
        if (time_before(jiffies, tmp102->ready_time)) {
                dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
                return -EAGAIN;
        }
 
-       tmp102_update_device(dev);
+       ret = regmap_read(tmp102->regmap, TMP102_TEMP_REG, &reg);
+       if (ret < 0)
+               return ret;
 
-       *temp = tmp102->temp[0];
+       *temp = tmp102_reg_to_mC(reg);
 
        return 0;
 }
@@ -131,13 +105,19 @@ static ssize_t tmp102_show_temp(struct device *dev,
 {
        struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
        struct tmp102 *tmp102 = dev_get_drvdata(dev);
+       int regaddr = sda->index;
+       unsigned int reg;
+       int err;
 
-       if (time_before(jiffies, tmp102->ready_time))
+       if (regaddr == TMP102_TEMP_REG &&
+           time_before(jiffies, tmp102->ready_time))
                return -EAGAIN;
 
-       tmp102_update_device(dev);
+       err = regmap_read(tmp102->regmap, regaddr, &reg);
+       if (err < 0)
+               return err;
 
-       return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
+       return sprintf(buf, "%d\n", tmp102_reg_to_mC(reg));
 }
 
 static ssize_t tmp102_set_temp(struct device *dev,
@@ -146,29 +126,26 @@ static ssize_t tmp102_set_temp(struct device *dev,
 {
        struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
        struct tmp102 *tmp102 = dev_get_drvdata(dev);
-       struct i2c_client *client = tmp102->client;
+       int reg = sda->index;
        long val;
-       int status;
+       int err;
 
        if (kstrtol(buf, 10, &val) < 0)
                return -EINVAL;
        val = clamp_val(val, -256000, 255000);
 
-       mutex_lock(&tmp102->lock);
-       tmp102->temp[sda->index] = val;
-       status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
-                                             tmp102_mC_to_reg(val));
-       mutex_unlock(&tmp102->lock);
-       return status ? : count;
+       err = regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(val));
+       return err ? : count;
 }
 
-static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL,
+                         TMP102_TEMP_REG);
 
 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
-                         tmp102_set_temp, 1);
+                         tmp102_set_temp, TMP102_TLOW_REG);
 
 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
-                         tmp102_set_temp, 2);
+                         tmp102_set_temp, TMP102_THIGH_REG);
 
 static struct attribute *tmp102_attrs[] = {
        &sensor_dev_attr_temp1_input.dev_attr.attr,
@@ -185,19 +162,39 @@ static const struct thermal_zone_of_device_ops tmp102_of_thermal_ops = {
 static void tmp102_restore_config(void *data)
 {
        struct tmp102 *tmp102 = data;
-       struct i2c_client *client = tmp102->client;
 
-       i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
-                                    tmp102->config_orig);
+       regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
+}
+
+static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+       return reg != TMP102_TEMP_REG;
 }
 
+static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+       return reg == TMP102_TEMP_REG;
+}
+
+static const struct regmap_config tmp102_regmap_config = {
+       .reg_bits = 8,
+       .val_bits = 16,
+       .max_register = TMP102_THIGH_REG,
+       .writeable_reg = tmp102_is_writeable_reg,
+       .volatile_reg = tmp102_is_volatile_reg,
+       .val_format_endian = REGMAP_ENDIAN_BIG,
+       .cache_type = REGCACHE_RBTREE,
+       .use_single_rw = true,
+};
+
 static int tmp102_probe(struct i2c_client *client,
                                  const struct i2c_device_id *id)
 {
        struct device *dev = &client->dev;
        struct device *hwmon_dev;
        struct tmp102 *tmp102;
-       int status;
+       unsigned int regval;
+       int err;
 
        if (!i2c_check_functionality(client->adapter,
                                     I2C_FUNC_SMBUS_WORD_DATA)) {
@@ -211,35 +208,36 @@ static int tmp102_probe(struct i2c_client *client,
                return -ENOMEM;
 
        i2c_set_clientdata(client, tmp102);
-       tmp102->client = client;
 
-       status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
-       if (status < 0) {
+       tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
+       if (IS_ERR(tmp102->regmap))
+               return PTR_ERR(tmp102->regmap);
+
+       err = regmap_read(tmp102->regmap, TMP102_CONF_REG, &regval);
+       if (err < 0) {
                dev_err(dev, "error reading config register\n");
-               return status;
+               return err;
        }
 
-       if ((status & ~TMP102_CONFREG_MASK) !=
+       if ((regval & ~TMP102_CONFREG_MASK) !=
            (TMP102_CONF_R0 | TMP102_CONF_R1)) {
                dev_err(dev, "unexpected config register value\n");
                return -ENODEV;
        }
 
-       tmp102->config_orig = status;
+       tmp102->config_orig = regval;
 
        devm_add_action(dev, tmp102_restore_config, tmp102);
 
-       status &= ~TMP102_CONFIG_CLEAR;
-       status |= TMP102_CONFIG_SET;
+       regval &= ~TMP102_CONFIG_CLEAR;
+       regval |= TMP102_CONFIG_SET;
 
-       status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, status);
-       if (status < 0) {
+       err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
+       if (err < 0) {
                dev_err(dev, "error writing config register\n");
-               return status;
+               return err;
        }
 
-       mutex_init(&tmp102->lock);
-
        tmp102->ready_time = jiffies;
        if (tmp102->config_orig & TMP102_CONF_SD) {
                /*
@@ -268,30 +266,24 @@ static int tmp102_probe(struct i2c_client *client,
 static int tmp102_suspend(struct device *dev)
 {
        struct i2c_client *client = to_i2c_client(dev);
-       int config;
-
-       config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
-       if (config < 0)
-               return config;
+       struct tmp102 *tmp102 = i2c_get_clientdata(client);
 
-       config |= TMP102_CONF_SD;
-       return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
+       return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
+                                 TMP102_CONF_SD, TMP102_CONF_SD);
 }
 
 static int tmp102_resume(struct device *dev)
 {
        struct i2c_client *client = to_i2c_client(dev);
        struct tmp102 *tmp102 = i2c_get_clientdata(client);
-       int config;
+       int err;
 
-       config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
-       if (config < 0)
-               return config;
+       err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
+                                TMP102_CONF_SD, 0);
 
        tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
 
-       config &= ~TMP102_CONF_SD;
-       return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
+       return err;
 }
 #endif /* CONFIG_PM */