hwmon: (lm95245) Use new hwmon registration API

Simplify code and reduce code size by using the new hwmon
registration API.

Other changes:

- Convert to use regmap, and drop local caching. This avoids reading
  registers unnecessarily, and uses regmap for caching of non-volatile
  registers.
- Add support for temp2_max, temp2_max_alarm, temp2_max_hyst, and
  temp2_offset.
- Order include files alphabetically
- Drop FSF address
- Check errors from register read and write functions and report
  to userspace.
- Accept negative hysteresis values. While unlikely, a maximum limit
  _can_ be set to a value smaller than 31 degrees C, which makes negative
  hysteresis values possible.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/lm95245.c

@@ -15,22 +15,16 @@
  * 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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include <linux/module.h>
+#include <linux/err.h>
 #include <linux/init.h>
-#include <linux/slab.h>
-#include <linux/jiffies.h>
-#include <linux/i2c.h>
 #include <linux/hwmon.h>
-#include <linux/hwmon-sysfs.h>
-#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
 #include <linux/mutex.h>
-#include <linux/sysfs.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
 
 static const unsigned short normal_i2c[] = {
 	0x18, 0x19, 0x29, 0x4c, 0x4d, I2C_CLIENT_END };
@@ -89,6 +83,7 @@ static const unsigned short normal_i2c[] = {
 #define RATE_CR1000	0x02
 #define RATE_CR2500	0x03
 
+#define STATUS1_ROS		0x10
 #define STATUS1_DIODE_FAULT	0x04
 #define STATUS1_RTCRIT		0x02
 #define STATUS1_LOC		0x01
@@ -112,14 +107,9 @@ static const u8 lm95245_reg_address[] = {
 
 /* Client data (each client gets its own) */
 struct lm95245_data {
-	struct i2c_client *client;
+	struct regmap *regmap;
 	struct mutex update_lock;
-	unsigned long last_updated;	/* in jiffies */
-	unsigned long interval;	/* in msecs */
-	bool valid;		/* zero until following fields are valid */
-	/* registers values */
-	u8 regs[ARRAY_SIZE(lm95245_reg_address)];
-	u8 config1, config2;
+	int interval;	/* in msecs */
 };
 
 /* Conversions */
@@ -135,60 +125,36 @@ static int temp_from_reg_signed(u8 val_h, u8 val_l)
 	return temp_from_reg_unsigned(val_h, val_l);
 }
 
-static struct lm95245_data *lm95245_update_device(struct device *dev)
-{
-	struct lm95245_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
-
-	mutex_lock(&data->update_lock);
-
-	if (time_after(jiffies, data->last_updated
-		+ msecs_to_jiffies(data->interval)) || !data->valid) {
-		int i;
-
-		for (i = 0; i < ARRAY_SIZE(lm95245_reg_address); i++)
-			data->regs[i]
-			  = i2c_smbus_read_byte_data(client,
-						     lm95245_reg_address[i]);
-		data->last_updated = jiffies;
-		data->valid = 1;
-	}
-
-	mutex_unlock(&data->update_lock);
-
-	return data;
-}
-
-static unsigned long lm95245_read_conversion_rate(struct i2c_client *client)
+static int lm95245_read_conversion_rate(struct lm95245_data *data)
 {
-	int rate;
-	unsigned long interval;
+	unsigned int rate;
+	int ret;
 
-	rate = i2c_smbus_read_byte_data(client, LM95245_REG_RW_CONVERS_RATE);
+	ret = regmap_read(data->regmap, LM95245_REG_RW_CONVERS_RATE, &rate);
+	if (ret < 0)
+		return ret;
 
 	switch (rate) {
 	case RATE_CR0063:
-		interval = 63;
+		data->interval = 63;
 		break;
 	case RATE_CR0364:
-		interval = 364;
+		data->interval = 364;
 		break;
 	case RATE_CR1000:
-		interval = 1000;
+		data->interval = 1000;
 		break;
 	case RATE_CR2500:
 	default:
-		interval = 2500;
+		data->interval = 2500;
 		break;
 	}
-
-	return interval;
+	return 0;
 }
 
-static unsigned long lm95245_set_conversion_rate(struct i2c_client *client,
-			unsigned long interval)
+static int lm95245_set_conversion_rate(struct lm95245_data *data, long interval)
 {
-	int rate;
+	int ret, rate;
 
 	if (interval <= 63) {
 		interval = 63;
@@ -204,220 +170,288 @@ static unsigned long lm95245_set_conversion_rate(struct i2c_client *client,
 		rate = RATE_CR2500;
 	}
 
-	i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONVERS_RATE, rate);
+	ret = regmap_write(data->regmap, LM95245_REG_RW_CONVERS_RATE, rate);
+	if (ret < 0)
+		return ret;
 
-	return interval;
+	data->interval = interval;
+	return 0;
 }
 
-/* Sysfs stuff */
-static ssize_t show_input(struct device *dev, struct device_attribute *attr,
-			  char *buf)
+static int lm95245_read_temp(struct device *dev, u32 attr, int channel,
+			     long *val)
 {
-	struct lm95245_data *data = lm95245_update_device(dev);
-	int temp;
-	int index = to_sensor_dev_attr(attr)->index;
-
+	struct lm95245_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
+	int ret, regl, regh, regvall, regvalh;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		regl = channel ? LM95245_REG_R_REMOTE_TEMPL_S :
+				 LM95245_REG_R_LOCAL_TEMPL_S;
+		regh = channel ? LM95245_REG_R_REMOTE_TEMPH_S :
+				 LM95245_REG_R_LOCAL_TEMPH_S;
+		ret = regmap_read(regmap, regl, &regvall);
+		if (ret < 0)
+			return ret;
+		ret = regmap_read(regmap, regh, &regvalh);
+		if (ret < 0)
+			return ret;
 		/*
-	 * Index 0 (Local temp) is always signed
-	 * Index 2 (Remote temp) has both signed and unsigned data
-	 * use signed calculation for remote if signed bit is set
+		 * Local temp is always signed.
+		 * Remote temp has both signed and unsigned data.
+		 * Use signed calculation for remote if signed bit is set
+		 * or if reported temperature is below signed limit.
 		 */
-	if (index == 0 || data->regs[index] & 0x80)
-		temp = temp_from_reg_signed(data->regs[index],
-			    data->regs[index + 1]);
-	else
-		temp = temp_from_reg_unsigned(data->regs[index + 2],
-			    data->regs[index + 3]);
-
-	return snprintf(buf, PAGE_SIZE - 1, "%d\n", temp);
-}
-
-static ssize_t show_limit(struct device *dev, struct device_attribute *attr,
-			 char *buf)
-{
-	struct lm95245_data *data = lm95245_update_device(dev);
-	int index = to_sensor_dev_attr(attr)->index;
-
-	return snprintf(buf, PAGE_SIZE - 1, "%d\n",
-			data->regs[index] * 1000);
+		if (!channel || (regvalh & 0x80) || regvalh < 0x7f) {
+			*val = temp_from_reg_signed(regvalh, regvall);
+			return 0;
+		}
+		ret = regmap_read(regmap, LM95245_REG_R_REMOTE_TEMPL_U,
+				  &regvall);
+		if (ret < 0)
+			return ret;
+		ret = regmap_read(regmap, LM95245_REG_R_REMOTE_TEMPH_U,
+				  &regvalh);
+		if (ret < 0)
+			return ret;
+		*val = temp_from_reg_unsigned(regvalh, regvall);
+		return 0;
+	case hwmon_temp_max:
+		ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT,
+				  &regvalh);
+		if (ret < 0)
+			return ret;
+		*val = regvalh * 1000;
+		return 0;
+	case hwmon_temp_crit:
+		regh = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
+				 LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
+		ret = regmap_read(regmap, regh, &regvalh);
+		if (ret < 0)
+			return ret;
+		*val = regvalh * 1000;
+		return 0;
+	case hwmon_temp_max_hyst:
+		ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT,
+				  &regvalh);
+		if (ret < 0)
+			return ret;
+		ret = regmap_read(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
+				  &regvall);
+		if (ret < 0)
+			return ret;
+		*val = (regvalh - regvall) * 1000;
+		return 0;
+	case hwmon_temp_crit_hyst:
+		regh = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
+				 LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
+		ret = regmap_read(regmap, regh, &regvalh);
+		if (ret < 0)
+			return ret;
+		ret = regmap_read(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
+				  &regvall);
+		if (ret < 0)
+			return ret;
+		*val = (regvalh - regvall) * 1000;
+		return 0;
+	case hwmon_temp_type:
+		ret = regmap_read(regmap, LM95245_REG_RW_CONFIG2, &regvalh);
+		if (ret < 0)
+			return ret;
+		*val = (regvalh & CFG2_REMOTE_TT) ? 1 : 2;
+		return 0;
+	case hwmon_temp_offset:
+		ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OFFL,
+				  &regvall);
+		if (ret < 0)
+			return ret;
+		ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OFFH,
+				  &regvalh);
+		if (ret < 0)
+			return ret;
+		*val = temp_from_reg_signed(regvalh, regvall);
+		return 0;
+	case hwmon_temp_max_alarm:
+		ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regvalh);
+		if (ret < 0)
+			return ret;
+		*val = !!(regvalh & STATUS1_ROS);
+		return 0;
+	case hwmon_temp_crit_alarm:
+		ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regvalh);
+		if (ret < 0)
+			return ret;
+		*val = !!(regvalh & (channel ? STATUS1_RTCRIT : STATUS1_LOC));
+		return 0;
+	case hwmon_temp_fault:
+		ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regvalh);
+		if (ret < 0)
+			return ret;
+		*val = !!(regvalh & STATUS1_DIODE_FAULT);
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
-static ssize_t set_limit(struct device *dev, struct device_attribute *attr,
-			const char *buf, size_t count)
+static int lm95245_write_temp(struct device *dev, u32 attr, int channel,
+			      long val)
 {
 	struct lm95245_data *data = dev_get_drvdata(dev);
-	int index = to_sensor_dev_attr(attr)->index;
-	struct i2c_client *client = data->client;
-	unsigned long val;
-
-	if (kstrtoul(buf, 10, &val) < 0)
-		return -EINVAL;
-
-	val /= 1000;
-
-	val = clamp_val(val, 0, (index == 6 ? 127 : 255));
-
+	struct regmap *regmap = data->regmap;
+	unsigned int regval;
+	int ret, reg;
+
+	switch (attr) {
+	case hwmon_temp_max:
+		val = clamp_val(val / 1000, 0, 255);
+		ret = regmap_write(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT, val);
+		return ret;
+	case hwmon_temp_crit:
+		reg = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
+				LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
+		val = clamp_val(val / 1000, 0, channel ? 255 : 127);
+		ret = regmap_write(regmap, reg, val);
+		return ret;
+	case hwmon_temp_crit_hyst:
 		mutex_lock(&data->update_lock);
-
-	data->valid = 0;
-
-	i2c_smbus_write_byte_data(client, lm95245_reg_address[index], val);
-
+		ret = regmap_read(regmap, LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT,
+				  &regval);
+		if (ret < 0) {
 			mutex_unlock(&data->update_lock);
-
-	return count;
-}
-
-static ssize_t show_crit_hyst(struct device *dev, struct device_attribute *attr,
-			char *buf)
-{
-	struct lm95245_data *data = lm95245_update_device(dev);
-	int index = to_sensor_dev_attr(attr)->index;
-	int hyst = data->regs[index] - data->regs[8];
-
-	return snprintf(buf, PAGE_SIZE - 1, "%d\n", hyst * 1000);
-}
-
-static ssize_t set_crit_hyst(struct device *dev, struct device_attribute *attr,
-			const char *buf, size_t count)
-{
-	struct lm95245_data *data = dev_get_drvdata(dev);
-	int index = to_sensor_dev_attr(attr)->index;
-	struct i2c_client *client = data->client;
-	unsigned long val;
-	int hyst, limit;
-
-	if (kstrtoul(buf, 10, &val) < 0)
-		return -EINVAL;
-
+			return ret;
+		}
+		/* Clamp to reasonable range to prevent overflow */
+		val = clamp_val(val, -1000000, 1000000);
+		val = regval - val / 1000;
+		val = clamp_val(val, 0, 31);
+		ret = regmap_write(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
+				   val);
+		mutex_unlock(&data->update_lock);
+		return ret;
+	case hwmon_temp_offset:
+		val = clamp_val(val, -128000, 127875);
+		val = val * 256 / 1000;
 		mutex_lock(&data->update_lock);
-
-	limit = i2c_smbus_read_byte_data(client, lm95245_reg_address[index]);
-	hyst = limit - val / 1000;
-	hyst = clamp_val(hyst, 0, 31);
-	data->regs[8] = hyst;
-
-	/* shared crit hysteresis */
-	i2c_smbus_write_byte_data(client, LM95245_REG_RW_COMMON_HYSTERESIS,
-		hyst);
-
+		ret = regmap_write(regmap, LM95245_REG_RW_REMOTE_OFFL,
+				   val & 0xe0);
+		if (ret < 0) {
 			mutex_unlock(&data->update_lock);
-
-	return count;
+			return ret;
+		}
+		ret = regmap_write(regmap, LM95245_REG_RW_REMOTE_OFFH,
+				   (val >> 8) & 0xff);
+		mutex_unlock(&data->update_lock);
+		return ret;
+	case hwmon_temp_type:
+		if (val != 1 && val != 2)
+			return -EINVAL;
+		ret = regmap_update_bits(regmap, LM95245_REG_RW_CONFIG2,
+					 CFG2_REMOTE_TT,
+					 val == 1 ? CFG2_REMOTE_TT : 0);
+		return ret;
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
-static ssize_t show_type(struct device *dev, struct device_attribute *attr,
-			 char *buf)
+static int lm95245_read_chip(struct device *dev, u32 attr, int channel,
+			     long *val)
 {
 	struct lm95245_data *data = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE - 1,
-		data->config2 & CFG2_REMOTE_TT ? "1\n" : "2\n");
+	switch (attr) {
+	case hwmon_chip_update_interval:
+		*val = data->interval;
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
-static ssize_t set_type(struct device *dev, struct device_attribute *attr,
-			const char *buf, size_t count)
+static int lm95245_write_chip(struct device *dev, u32 attr, int channel,
+			      long val)
 {
 	struct lm95245_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
-	unsigned long val;
-
-	if (kstrtoul(buf, 10, &val) < 0)
-		return -EINVAL;
-	if (val != 1 && val != 2)
-		return -EINVAL;
+	int ret;
 
+	switch (attr) {
+	case hwmon_chip_update_interval:
 		mutex_lock(&data->update_lock);
-
-	if (val == 1)
-		data->config2 |= CFG2_REMOTE_TT;
-	else
-		data->config2 &= ~CFG2_REMOTE_TT;
-
-	data->valid = 0;
-
-	i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG2,
-				  data->config2);
-
+		ret = lm95245_set_conversion_rate(data, val);
 		mutex_unlock(&data->update_lock);
-
-	return count;
+		return ret;
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
-static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
-			 char *buf)
+static int lm95245_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
 {
-	struct lm95245_data *data = lm95245_update_device(dev);
-	int index = to_sensor_dev_attr(attr)->index;
-
-	return snprintf(buf, PAGE_SIZE - 1, "%d\n",
-			!!(data->regs[9] & index));
+	switch (type) {
+	case hwmon_chip:
+		return lm95245_read_chip(dev, attr, channel, val);
+	case hwmon_temp:
+		return lm95245_read_temp(dev, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
-static ssize_t show_interval(struct device *dev, struct device_attribute *attr,
-			     char *buf)
+static int lm95245_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
 {
-	struct lm95245_data *data = lm95245_update_device(dev);
-
-	return snprintf(buf, PAGE_SIZE - 1, "%lu\n", data->interval);
+	switch (type) {
+	case hwmon_chip:
+		return lm95245_write_chip(dev, attr, channel, val);
+	case hwmon_temp:
+		return lm95245_write_temp(dev, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
-static ssize_t set_interval(struct device *dev, struct device_attribute *attr,
-			    const char *buf, size_t count)
+static umode_t lm95245_temp_is_visible(const void *data, u32 attr, int channel)
 {
-	struct lm95245_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
-	unsigned long val;
-
-	if (kstrtoul(buf, 10, &val) < 0)
-		return -EINVAL;
-
-	mutex_lock(&data->update_lock);
-
-	data->interval = lm95245_set_conversion_rate(client, val);
-
-	mutex_unlock(&data->update_lock);
-
-	return count;
+	switch (attr) {
+	case hwmon_temp_input:
+	case hwmon_temp_max_alarm:
+	case hwmon_temp_max_hyst:
+	case hwmon_temp_crit_alarm:
+	case hwmon_temp_fault:
+		return S_IRUGO;
+	case hwmon_temp_type:
+	case hwmon_temp_max:
+	case hwmon_temp_crit:
+	case hwmon_temp_offset:
+		return S_IRUGO | S_IWUSR;
+	case hwmon_temp_crit_hyst:
+		return (channel == 0) ? S_IRUGO | S_IWUSR : S_IRUGO;
+	default:
+		return 0;
+	}
 }
 
-static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
-static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_limit,
-		set_limit, 6);
-static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_crit_hyst,
-		set_crit_hyst, 6);
-static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
-		STATUS1_LOC);
-
-static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
-static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_limit,
-		set_limit, 7);
-static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_crit_hyst, NULL, 7);
-static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL,
-		STATUS1_RTCRIT);
-static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type,
-		set_type, 0);
-static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL,
-		STATUS1_DIODE_FAULT);
-
-static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
-		set_interval);
-
-static struct attribute *lm95245_attrs[] = {
-	&sensor_dev_attr_temp1_input.dev_attr.attr,
-	&sensor_dev_attr_temp1_crit.dev_attr.attr,
-	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
-	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp2_input.dev_attr.attr,
-	&sensor_dev_attr_temp2_crit.dev_attr.attr,
-	&sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
-	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp2_type.dev_attr.attr,
-	&sensor_dev_attr_temp2_fault.dev_attr.attr,
-	&dev_attr_update_interval.attr,
-	NULL
-};
-ATTRIBUTE_GROUPS(lm95245);
+static umode_t lm95245_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 S_IRUGO | S_IWUSR;
+		default:
+			return 0;
+		}
+	case hwmon_temp:
+		return lm95245_temp_is_visible(data, attr, channel);
+	default:
+		return 0;
+	}
+}
 
 /* Return 0 if detection is successful, -ENODEV otherwise */
 static int lm95245_detect(struct i2c_client *new_client,
@@ -453,44 +487,130 @@ static int lm95245_detect(struct i2c_client *new_client,
 	return 0;
 }
 
-static void lm95245_init_client(struct i2c_client *client,
-				struct lm95245_data *data)
+static int lm95245_init_client(struct lm95245_data *data)
 {
-	data->interval = lm95245_read_conversion_rate(client);
-
-	data->config1 = i2c_smbus_read_byte_data(client,
-		LM95245_REG_RW_CONFIG1);
-	data->config2 = i2c_smbus_read_byte_data(client,
-		LM95245_REG_RW_CONFIG2);
-
-	if (data->config1 & CFG_STOP) {
-		/* Clear the standby bit */
-		data->config1 &= ~CFG_STOP;
-		i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG1,
-			data->config1);
+	int ret;
+
+	ret = lm95245_read_conversion_rate(data);
+	if (ret < 0)
+		return ret;
+
+	return regmap_update_bits(data->regmap, LM95245_REG_RW_CONFIG1,
+				  CFG_STOP, 0);
+}
+
+static bool lm95245_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case LM95245_REG_RW_CONFIG1:
+	case LM95245_REG_RW_CONVERS_RATE:
+	case LM95245_REG_W_ONE_SHOT:
+	case LM95245_REG_RW_CONFIG2:
+	case LM95245_REG_RW_REMOTE_OFFH:
+	case LM95245_REG_RW_REMOTE_OFFL:
+	case LM95245_REG_RW_REMOTE_OS_LIMIT:
+	case LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT:
+	case LM95245_REG_RW_REMOTE_TCRIT_LIMIT:
+	case LM95245_REG_RW_COMMON_HYSTERESIS:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool lm95245_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case LM95245_REG_R_STATUS1:
+	case LM95245_REG_R_STATUS2:
+	case LM95245_REG_R_LOCAL_TEMPH_S:
+	case LM95245_REG_R_LOCAL_TEMPL_S:
+	case LM95245_REG_R_REMOTE_TEMPH_S:
+	case LM95245_REG_R_REMOTE_TEMPL_S:
+	case LM95245_REG_R_REMOTE_TEMPH_U:
+	case LM95245_REG_R_REMOTE_TEMPL_U:
+		return true;
+	default:
+		return false;
 	}
 }
 
+static const struct regmap_config lm95245_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.writeable_reg = lm95245_is_writeable_reg,
+	.volatile_reg = lm95245_is_volatile_reg,
+	.cache_type = REGCACHE_RBTREE,
+	.use_single_rw = true,
+};
+
+static const u32 lm95245_chip_config[] = {
+	HWMON_C_UPDATE_INTERVAL,
+	0
+};
+
+static const struct hwmon_channel_info lm95245_chip = {
+	.type = hwmon_chip,
+	.config = lm95245_chip_config,
+};
+
+static const u32 lm95245_temp_config[] = {
+	HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_CRIT_ALARM,
+	HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST | HWMON_T_CRIT |
+		HWMON_T_CRIT_HYST | HWMON_T_FAULT | HWMON_T_MAX_ALARM |
+		HWMON_T_CRIT_ALARM | HWMON_T_TYPE | HWMON_T_OFFSET,
+	0
+};
+
+static const struct hwmon_channel_info lm95245_temp = {
+	.type = hwmon_temp,
+	.config = lm95245_temp_config,
+};
+
+static const struct hwmon_channel_info *lm95245_info[] = {
+	&lm95245_chip,
+	&lm95245_temp,
+	NULL
+};
+
+static const struct hwmon_ops lm95245_hwmon_ops = {
+	.is_visible = lm95245_is_visible,
+	.read = lm95245_read,
+	.write = lm95245_write,
+};
+
+static const struct hwmon_chip_info lm95245_chip_info = {
+	.ops = &lm95245_hwmon_ops,
+	.info = lm95245_info,
+};
+
 static int lm95245_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
 	struct lm95245_data *data;
 	struct device *hwmon_dev;
+	int ret;
 
 	data = devm_kzalloc(dev, sizeof(struct lm95245_data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
 
-	data->client = client;
+	data->regmap = devm_regmap_init_i2c(client, &lm95245_regmap_config);
+	if (IS_ERR(data->regmap))
+		return PTR_ERR(data->regmap);
+
 	mutex_init(&data->update_lock);
 
 	/* Initialize the LM95245 chip */
-	lm95245_init_client(client, data);
+	ret = lm95245_init_client(data);
+	if (ret < 0)
+		return ret;
 
-	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 							 data,
-							   lm95245_groups);
+							 &lm95245_chip_info,
+							 NULL);
 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }