[PATCH v2 0/5] hwmon: (max1668) Modernize driver

[PATCH v2 0/5] hwmon: (max1668) Modernize driver

[Guenter Roeck]

Clean up driver and convert it to use regmap and with_info hardware
monitoring API to reduce code size and to make it easier to maintain.

v2:
- Added Reviewed-by: tags
- Dropped no longer needed include files
- Fixed wrong fault bit in regmap conversion patch

----------------------------------------------------------------
Guenter Roeck (5):
      hwmon: (max1668) Reorder include files to alphabetic order
      hwmon: (max1668) Use BIT macro
      hwmon: (max1668) Convert to use regmap
      hwmon: (max1668) Replace chip type with number of channels
      hwmon: (max1668) Convert to use with_info hwmon API

 drivers/hwmon/max1668.c | 487 ++++++++++++++++++------------------------------
 1 file changed, 180 insertions(+), 307 deletions(-)

[PATCH v2 1/5] hwmon: (max1668) Reorder include files to alphabetic order

[Guenter Roeck]

Reorder include files to alphabetic order to simplify driver maintenance.

Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Added Reviewed-by: tag

 drivers/hwmon/max1668.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/hwmon/max1668.c b/drivers/hwmon/max1668.c
index 9fc583ebb11b..f5b5cc29da17 100644
--- a/drivers/hwmon/max1668.c
+++ b/drivers/hwmon/max1668.c
@@ -6,15 +6,15 @@
  * some credit to Christoph Scheurer, but largely a rewrite
  */
 
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/slab.h>
-#include <linux/jiffies.h>
-#include <linux/i2c.h>
+#include <linux/err.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
-#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/slab.h>
 
 /* Addresses to scan */
 static const unsigned short max1668_addr_list[] = {
-- 
2.39.2

[PATCH v2 2/5] hwmon: (max1668) Use BIT macro

[Guenter Roeck]

Use bit macro to make the code easier to understand and reduce duplication.

Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Added Reviewed-by: tag

 drivers/hwmon/max1668.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/max1668.c b/drivers/hwmon/max1668.c
index f5b5cc29da17..83085ed0ae7e 100644
--- a/drivers/hwmon/max1668.c
+++ b/drivers/hwmon/max1668.c
@@ -6,6 +6,7 @@
  * some credit to Christoph Scheurer, but largely a rewrite
  */
 
+#include <linux/bits.h>
 #include <linux/err.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
@@ -172,7 +173,7 @@ static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 	if (IS_ERR(data))
 		return PTR_ERR(data);
 
-	return sprintf(buf, "%u\n", (data->alarms >> index) & 0x1);
+	return sprintf(buf, "%u\n", !!(data->alarms & BIT(index)));
 }
 
 static ssize_t show_fault(struct device *dev,
@@ -185,7 +186,7 @@ static ssize_t show_fault(struct device *dev,
 		return PTR_ERR(data);
 
 	return sprintf(buf, "%u\n",
-		       (data->alarms & (1 << 12)) && data->temp[index] == 127);
+		       (data->alarms & BIT(12)) && data->temp[index] == 127);
 }
 
 static ssize_t set_temp_max(struct device *dev,
-- 
2.39.2

[PATCH v2 3/5] hwmon: (max1668) Convert to use regmap

[Guenter Roeck]

Use regmap for caching to simplify the code and to hide read/write
register address differences.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Dropped no longer needed jiffies.h and mutex.h includes
    Fixed wrong fault bit mask

 drivers/hwmon/max1668.c | 215 ++++++++++++++++++----------------------
 1 file changed, 99 insertions(+), 116 deletions(-)

diff --git a/drivers/hwmon/max1668.c b/drivers/hwmon/max1668.c
index 83085ed0ae7e..c7eae28c0b01 100644
--- a/drivers/hwmon/max1668.c
+++ b/drivers/hwmon/max1668.c
@@ -6,15 +6,15 @@
  * some credit to Christoph Scheurer, but largely a rewrite
  */
 
+#include <linux/bitops.h>
 #include <linux/bits.h>
 #include <linux/err.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
-#include <linux/jiffies.h>
 #include <linux/module.h>
-#include <linux/mutex.h>
+#include <linux/regmap.h>
 #include <linux/slab.h>
 
 /* Addresses to scan */
@@ -31,14 +31,10 @@ static const unsigned short max1668_addr_list[] = {
 
 /* limits */
 
-/* write high limits */
-#define MAX1668_REG_LIMH_WR(nr)	(0x13 + 2 * (nr))
-/* write low limits */
-#define MAX1668_REG_LIML_WR(nr)	(0x14 + 2 * (nr))
-/* read high limits */
-#define MAX1668_REG_LIMH_RD(nr)	(0x08 + 2 * (nr))
+/* high limits */
+#define MAX1668_REG_LIMH(nr)	(0x08 + 2 * (nr))
 /* read low limits */
-#define MAX1668_REG_LIML_RD(nr)	(0x09 + 2 * (nr))
+#define MAX1668_REG_LIML(nr)	(0x09 + 2 * (nr))
 
 /* manufacturer and device ID Constants */
 #define MAN_ID_MAXIM		0x4d
@@ -54,139 +50,91 @@ MODULE_PARM_DESC(read_only, "Don't set any values, read only mode");
 enum chips { max1668, max1805, max1989 };
 
 struct max1668_data {
-	struct i2c_client *client;
+	struct regmap *regmap;
 	const struct attribute_group *groups[3];
 	enum chips type;
-
-	struct mutex update_lock;
-	bool valid;		/* true if following fields are valid */
-	unsigned long last_updated;	/* In jiffies */
-
-	/* 1x local and 4x remote */
-	s8 temp_max[5];
-	s8 temp_min[5];
-	s8 temp[5];
-	u16 alarms;
 };
 
-static struct max1668_data *max1668_update_device(struct device *dev)
-{
-	struct max1668_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
-	struct max1668_data *ret = data;
-	s32 val;
-	int i;
-
-	mutex_lock(&data->update_lock);
-
-	if (data->valid && !time_after(jiffies,
-			data->last_updated + HZ + HZ / 2))
-		goto abort;
-
-	for (i = 0; i < 5; i++) {
-		val = i2c_smbus_read_byte_data(client, MAX1668_REG_TEMP(i));
-		if (unlikely(val < 0)) {
-			ret = ERR_PTR(val);
-			goto abort;
-		}
-		data->temp[i] = (s8) val;
-
-		val = i2c_smbus_read_byte_data(client, MAX1668_REG_LIMH_RD(i));
-		if (unlikely(val < 0)) {
-			ret = ERR_PTR(val);
-			goto abort;
-		}
-		data->temp_max[i] = (s8) val;
-
-		val = i2c_smbus_read_byte_data(client, MAX1668_REG_LIML_RD(i));
-		if (unlikely(val < 0)) {
-			ret = ERR_PTR(val);
-			goto abort;
-		}
-		data->temp_min[i] = (s8) val;
-	}
-
-	val = i2c_smbus_read_byte_data(client, MAX1668_REG_STAT1);
-	if (unlikely(val < 0)) {
-		ret = ERR_PTR(val);
-		goto abort;
-	}
-	data->alarms = val << 8;
-
-	val = i2c_smbus_read_byte_data(client, MAX1668_REG_STAT2);
-	if (unlikely(val < 0)) {
-		ret = ERR_PTR(val);
-		goto abort;
-	}
-	data->alarms |= val;
-
-	data->last_updated = jiffies;
-	data->valid = true;
-abort:
-	mutex_unlock(&data->update_lock);
-
-	return ret;
-}
-
 static ssize_t show_temp(struct device *dev,
 			 struct device_attribute *devattr, char *buf)
 {
 	int index = to_sensor_dev_attr(devattr)->index;
-	struct max1668_data *data = max1668_update_device(dev);
+	struct max1668_data *data = dev_get_drvdata(dev);
+	u32 temp;
+	int ret;
 
-	if (IS_ERR(data))
-		return PTR_ERR(data);
+	ret = regmap_read(data->regmap, MAX1668_REG_TEMP(index), &temp);
+	if (ret)
+		return ret;
 
-	return sprintf(buf, "%d\n", data->temp[index] * 1000);
+	return sprintf(buf, "%d\n", sign_extend32(temp, 7) * 1000);
 }
 
 static ssize_t show_temp_max(struct device *dev,
 			     struct device_attribute *devattr, char *buf)
 {
 	int index = to_sensor_dev_attr(devattr)->index;
-	struct max1668_data *data = max1668_update_device(dev);
+	struct max1668_data *data = dev_get_drvdata(dev);
+	u32 temp;
+	int ret;
 
-	if (IS_ERR(data))
-		return PTR_ERR(data);
+	ret = regmap_read(data->regmap, MAX1668_REG_LIMH(index), &temp);
+	if (ret)
+		return ret;
 
-	return sprintf(buf, "%d\n", data->temp_max[index] * 1000);
+	return sprintf(buf, "%d\n", sign_extend32(temp, 7) * 1000);
 }
 
 static ssize_t show_temp_min(struct device *dev,
 			     struct device_attribute *devattr, char *buf)
 {
 	int index = to_sensor_dev_attr(devattr)->index;
-	struct max1668_data *data = max1668_update_device(dev);
+	struct max1668_data *data = dev_get_drvdata(dev);
+	u32 temp;
+	int ret;
 
-	if (IS_ERR(data))
-		return PTR_ERR(data);
+	ret = regmap_read(data->regmap, MAX1668_REG_LIML(index), &temp);
+	if (ret)
+		return ret;
 
-	return sprintf(buf, "%d\n", data->temp_min[index] * 1000);
+	return sprintf(buf, "%d\n", sign_extend32(temp, 7) * 1000);
 }
 
 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 			  char *buf)
 {
 	int index = to_sensor_dev_attr(attr)->index;
-	struct max1668_data *data = max1668_update_device(dev);
+	struct max1668_data *data = dev_get_drvdata(dev);
+	u32 alarm;
+	int ret;
 
-	if (IS_ERR(data))
-		return PTR_ERR(data);
+	ret = regmap_read(data->regmap,
+			  index >= 8 ? MAX1668_REG_STAT1 : MAX1668_REG_STAT2,
+			  &alarm);
+	if (ret)
+		return ret;
 
-	return sprintf(buf, "%u\n", !!(data->alarms & BIT(index)));
+	return sprintf(buf, "%u\n", !!(alarm & BIT(index & 7)));
 }
 
 static ssize_t show_fault(struct device *dev,
 			  struct device_attribute *devattr, char *buf)
 {
 	int index = to_sensor_dev_attr(devattr)->index;
-	struct max1668_data *data = max1668_update_device(dev);
+	struct max1668_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
+	u32 alarm, temp;
+	int ret;
 
-	if (IS_ERR(data))
-		return PTR_ERR(data);
+	ret = regmap_read(regmap, MAX1668_REG_STAT1, &alarm);
+	if (ret)
+		return ret;
 
-	return sprintf(buf, "%u\n",
-		       (data->alarms & BIT(12)) && data->temp[index] == 127);
+	ret = regmap_read(regmap, MAX1668_REG_TEMP(index), &temp);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%u\n", (alarm & BIT(4)) && temp == 127);
 }
 
 static ssize_t set_temp_max(struct device *dev,
@@ -195,7 +143,6 @@ static ssize_t set_temp_max(struct device *dev,
 {
 	int index = to_sensor_dev_attr(devattr)->index;
 	struct max1668_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
 	long temp;
 	int ret;
 
@@ -203,14 +150,10 @@ static ssize_t set_temp_max(struct device *dev,
 	if (ret < 0)
 		return ret;
 
-	mutex_lock(&data->update_lock);
-	data->temp_max[index] = clamp_val(temp/1000, -128, 127);
-	ret = i2c_smbus_write_byte_data(client,
-					MAX1668_REG_LIMH_WR(index),
-					data->temp_max[index]);
+	temp = clamp_val(temp / 1000, -128, 127);
+	ret = regmap_write(data->regmap, MAX1668_REG_LIMH(index), temp);
 	if (ret < 0)
 		count = ret;
-	mutex_unlock(&data->update_lock);
 
 	return count;
 }
@@ -221,7 +164,6 @@ static ssize_t set_temp_min(struct device *dev,
 {
 	int index = to_sensor_dev_attr(devattr)->index;
 	struct max1668_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
 	long temp;
 	int ret;
 
@@ -229,14 +171,10 @@ static ssize_t set_temp_min(struct device *dev,
 	if (ret < 0)
 		return ret;
 
-	mutex_lock(&data->update_lock);
-	data->temp_min[index] = clamp_val(temp/1000, -128, 127);
-	ret = i2c_smbus_write_byte_data(client,
-					MAX1668_REG_LIML_WR(index),
-					data->temp_min[index]);
+	temp = clamp_val(temp / 1000, -128, 127);
+	ret = regmap_write(data->regmap, MAX1668_REG_LIML(index), temp);
 	if (ret < 0)
 		count = ret;
-	mutex_unlock(&data->update_lock);
 
 	return count;
 }
@@ -392,6 +330,48 @@ static int max1668_detect(struct i2c_client *client,
 	return 0;
 }
 
+/* regmap */
+
+static int max1668_reg_read(void *context, unsigned int reg, unsigned int *val)
+{
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(context, reg);
+	if (ret < 0)
+		return ret;
+
+	*val = ret;
+	return 0;
+}
+
+static int max1668_reg_write(void *context, unsigned int reg, unsigned int val)
+{
+	return i2c_smbus_write_byte_data(context, reg + 11, val);
+}
+
+static bool max1668_regmap_is_volatile(struct device *dev, unsigned int reg)
+{
+	return reg <= MAX1668_REG_STAT2;
+}
+
+static bool max1668_regmap_is_writeable(struct device *dev, unsigned int reg)
+{
+	return reg > MAX1668_REG_STAT2 && reg <= MAX1668_REG_LIML(4);
+}
+
+static const struct regmap_config max1668_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_MAPLE,
+	.volatile_reg = max1668_regmap_is_volatile,
+	.writeable_reg = max1668_regmap_is_writeable,
+};
+
+static const struct regmap_bus max1668_regmap_bus = {
+	.reg_write = max1668_reg_write,
+	.reg_read = max1668_reg_read,
+};
+
 static int max1668_probe(struct i2c_client *client)
 {
 	struct i2c_adapter *adapter = client->adapter;
@@ -406,9 +386,12 @@ static int max1668_probe(struct i2c_client *client)
 	if (!data)
 		return -ENOMEM;
 
-	data->client = client;
+	data->regmap = devm_regmap_init(dev, &max1668_regmap_bus, client,
+					&max1668_regmap_config);
+	if (IS_ERR(data->regmap))
+		return PTR_ERR(data->regmap);
+
 	data->type = (uintptr_t)i2c_get_match_data(client);
-	mutex_init(&data->update_lock);
 
 	/* sysfs hooks */
 	data->groups[0] = &max1668_group_common;
-- 
2.39.2

Re: [PATCH v2 3/5] hwmon: (max1668) Convert to use regmap

[Tzung-Bi Shih]

On Fri, Jul 26, 2024 at 03:16:01PM -0700, Guenter Roeck wrote:
> Use regmap for caching to simplify the code and to hide read/write
> register address differences.
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>

Re: [PATCH v2 3/5] hwmon: (max1668) Convert to use regmap

[Guenter Roeck]

On 7/26/24 22:04, Tzung-Bi Shih wrote:
> On Fri, Jul 26, 2024 at 03:16:01PM -0700, Guenter Roeck wrote:
>> Use regmap for caching to simplify the code and to hide read/write
>> register address differences.
>>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> 
> Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
> 
Thanks!

Guenter

[PATCH v2 4/5] hwmon: (max1668) Replace chip type with number of channels

[Guenter Roeck]

The only difference between supported chips is the number of channels.
Drop enum chips and list the number of channels in struct i2c_device_id
directly.

Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Added Reviewed-by: tag

 drivers/hwmon/max1668.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/hwmon/max1668.c b/drivers/hwmon/max1668.c
index c7eae28c0b01..f8180a8597c0 100644
--- a/drivers/hwmon/max1668.c
+++ b/drivers/hwmon/max1668.c
@@ -47,12 +47,10 @@ static bool read_only;
 module_param(read_only, bool, 0);
 MODULE_PARM_DESC(read_only, "Don't set any values, read only mode");
 
-enum chips { max1668, max1805, max1989 };
-
 struct max1668_data {
 	struct regmap *regmap;
 	const struct attribute_group *groups[3];
-	enum chips type;
+	int channels;
 };
 
 static ssize_t show_temp(struct device *dev,
@@ -391,11 +389,11 @@ static int max1668_probe(struct i2c_client *client)
 	if (IS_ERR(data->regmap))
 		return PTR_ERR(data->regmap);
 
-	data->type = (uintptr_t)i2c_get_match_data(client);
+	data->channels = (uintptr_t)i2c_get_match_data(client);
 
 	/* sysfs hooks */
 	data->groups[0] = &max1668_group_common;
-	if (data->type == max1668 || data->type == max1989)
+	if (data->channels == 5)
 		data->groups[1] = &max1668_group_unique;
 
 	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
@@ -404,9 +402,9 @@ static int max1668_probe(struct i2c_client *client)
 }
 
 static const struct i2c_device_id max1668_id[] = {
-	{ "max1668", max1668 },
-	{ "max1805", max1805 },
-	{ "max1989", max1989 },
+	{ "max1668", 5 },
+	{ "max1805", 3 },
+	{ "max1989", 5 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, max1668_id);
-- 
2.39.2

[PATCH v2 5/5] hwmon: (max1668) Convert to use with_info hwmon API

[Guenter Roeck]

Convert to use with_info API to simplify the code and to reduce its size.

This patch reduces object file size by approximately 25%.

Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Added Reviewed-by: tag

 drivers/hwmon/max1668.c | 337 ++++++++++++++--------------------------
 1 file changed, 114 insertions(+), 223 deletions(-)

diff --git a/drivers/hwmon/max1668.c b/drivers/hwmon/max1668.c
index f8180a8597c0..a8197a86f559 100644
--- a/drivers/hwmon/max1668.c
+++ b/drivers/hwmon/max1668.c
@@ -10,7 +10,6 @@
 #include <linux/bits.h>
 #include <linux/err.h>
 #include <linux/hwmon.h>
-#include <linux/hwmon-sysfs.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/module.h>
@@ -49,247 +48,144 @@ MODULE_PARM_DESC(read_only, "Don't set any values, read only mode");
 
 struct max1668_data {
 	struct regmap *regmap;
-	const struct attribute_group *groups[3];
 	int channels;
 };
 
-static ssize_t show_temp(struct device *dev,
-			 struct device_attribute *devattr, char *buf)
+static int max1668_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
 {
-	int index = to_sensor_dev_attr(devattr)->index;
-	struct max1668_data *data = dev_get_drvdata(dev);
-	u32 temp;
-	int ret;
-
-	ret = regmap_read(data->regmap, MAX1668_REG_TEMP(index), &temp);
-	if (ret)
-		return ret;
-
-	return sprintf(buf, "%d\n", sign_extend32(temp, 7) * 1000);
-}
-
-static ssize_t show_temp_max(struct device *dev,
-			     struct device_attribute *devattr, char *buf)
-{
-	int index = to_sensor_dev_attr(devattr)->index;
-	struct max1668_data *data = dev_get_drvdata(dev);
-	u32 temp;
-	int ret;
-
-	ret = regmap_read(data->regmap, MAX1668_REG_LIMH(index), &temp);
-	if (ret)
-		return ret;
-
-	return sprintf(buf, "%d\n", sign_extend32(temp, 7) * 1000);
-}
-
-static ssize_t show_temp_min(struct device *dev,
-			     struct device_attribute *devattr, char *buf)
-{
-	int index = to_sensor_dev_attr(devattr)->index;
-	struct max1668_data *data = dev_get_drvdata(dev);
-	u32 temp;
-	int ret;
-
-	ret = regmap_read(data->regmap, MAX1668_REG_LIML(index), &temp);
-	if (ret)
-		return ret;
-
-	return sprintf(buf, "%d\n", sign_extend32(temp, 7) * 1000);
-}
-
-static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
-			  char *buf)
-{
-	int index = to_sensor_dev_attr(attr)->index;
-	struct max1668_data *data = dev_get_drvdata(dev);
-	u32 alarm;
-	int ret;
-
-	ret = regmap_read(data->regmap,
-			  index >= 8 ? MAX1668_REG_STAT1 : MAX1668_REG_STAT2,
-			  &alarm);
-	if (ret)
-		return ret;
-
-	return sprintf(buf, "%u\n", !!(alarm & BIT(index & 7)));
-}
-
-static ssize_t show_fault(struct device *dev,
-			  struct device_attribute *devattr, char *buf)
-{
-	int index = to_sensor_dev_attr(devattr)->index;
 	struct max1668_data *data = dev_get_drvdata(dev);
 	struct regmap *regmap = data->regmap;
-	u32 alarm, temp;
+	u32 regs[2] = { MAX1668_REG_STAT1, MAX1668_REG_TEMP(channel) };
+	u8 regvals[2];
+	u32 regval;
 	int ret;
 
-	ret = regmap_read(regmap, MAX1668_REG_STAT1, &alarm);
-	if (ret)
-		return ret;
-
-	ret = regmap_read(regmap, MAX1668_REG_TEMP(index), &temp);
-	if (ret)
-		return ret;
-
-	return sprintf(buf, "%u\n", (alarm & BIT(4)) && temp == 127);
+	switch (attr) {
+	case hwmon_temp_input:
+		ret = regmap_read(regmap, MAX1668_REG_TEMP(channel), &regval);
+		if (ret)
+			return ret;
+		*val = sign_extend32(regval, 7) * 1000;
+		break;
+	case hwmon_temp_min:
+		ret = regmap_read(regmap, MAX1668_REG_LIML(channel), &regval);
+		if (ret)
+			return ret;
+		*val = sign_extend32(regval, 7) * 1000;
+		break;
+	case hwmon_temp_max:
+		ret = regmap_read(regmap, MAX1668_REG_LIMH(channel), &regval);
+		if (ret)
+			return ret;
+		*val = sign_extend32(regval, 7) * 1000;
+		break;
+	case hwmon_temp_min_alarm:
+		ret = regmap_read(regmap,
+				  channel ? MAX1668_REG_STAT2 : MAX1668_REG_STAT1,
+				  &regval);
+		if (ret)
+			return ret;
+		if (channel)
+			*val = !!(regval & BIT(9 - channel * 2));
+		else
+			*val = !!(regval & BIT(5));
+		break;
+	case hwmon_temp_max_alarm:
+		ret = regmap_read(regmap,
+				  channel ? MAX1668_REG_STAT2 : MAX1668_REG_STAT1,
+				  &regval);
+		if (ret)
+			return ret;
+		if (channel)
+			*val = !!(regval & BIT(8 - channel * 2));
+		else
+			*val = !!(regval & BIT(6));
+		break;
+	case hwmon_temp_fault:
+		ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
+		if (ret)
+			return ret;
+		*val = !!((regvals[0] & BIT(4)) && regvals[1] == 127);
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+	return 0;
 }
 
-static ssize_t set_temp_max(struct device *dev,
-			    struct device_attribute *devattr,
-			    const char *buf, size_t count)
+static int max1668_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
 {
-	int index = to_sensor_dev_attr(devattr)->index;
 	struct max1668_data *data = dev_get_drvdata(dev);
-	long temp;
-	int ret;
+	struct regmap *regmap = data->regmap;
 
-	ret = kstrtol(buf, 10, &temp);
-	if (ret < 0)
-		return ret;
+	val = clamp_val(val / 1000, -128, 127);
 
-	temp = clamp_val(temp / 1000, -128, 127);
-	ret = regmap_write(data->regmap, MAX1668_REG_LIMH(index), temp);
-	if (ret < 0)
-		count = ret;
-
-	return count;
+	switch (attr) {
+	case hwmon_temp_min:
+		return regmap_write(regmap, MAX1668_REG_LIML(channel), val);
+	case hwmon_temp_max:
+		return regmap_write(regmap, MAX1668_REG_LIMH(channel), val);
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
-static ssize_t set_temp_min(struct device *dev,
-			    struct device_attribute *devattr,
-			    const char *buf, size_t count)
+static umode_t max1668_is_visible(const void *_data, enum hwmon_sensor_types type,
+				  u32 attr, int channel)
 {
-	int index = to_sensor_dev_attr(devattr)->index;
-	struct max1668_data *data = dev_get_drvdata(dev);
-	long temp;
-	int ret;
+	const struct max1668_data *data = _data;
 
-	ret = kstrtol(buf, 10, &temp);
-	if (ret < 0)
-		return ret;
+	if (channel >= data->channels)
+		return 0;
 
-	temp = clamp_val(temp / 1000, -128, 127);
-	ret = regmap_write(data->regmap, MAX1668_REG_LIML(index), temp);
-	if (ret < 0)
-		count = ret;
-
-	return count;
+	switch (attr) {
+	case hwmon_temp_min:
+	case hwmon_temp_max:
+		return read_only ? 0444 : 0644;
+	case hwmon_temp_input:
+	case hwmon_temp_min_alarm:
+	case hwmon_temp_max_alarm:
+		return 0444;
+	case hwmon_temp_fault:
+		if (channel)
+			return 0444;
+		break;
+	default:
+		break;
+	}
+	return 0;
 }
 
-static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
-static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp_max,
-				set_temp_max, 0);
-static SENSOR_DEVICE_ATTR(temp1_min, S_IRUGO, show_temp_min,
-				set_temp_min, 0);
-static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp, NULL, 1);
-static SENSOR_DEVICE_ATTR(temp2_max, S_IRUGO, show_temp_max,
-				set_temp_max, 1);
-static SENSOR_DEVICE_ATTR(temp2_min, S_IRUGO, show_temp_min,
-				set_temp_min, 1);
-static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp, NULL, 2);
-static SENSOR_DEVICE_ATTR(temp3_max, S_IRUGO, show_temp_max,
-				set_temp_max, 2);
-static SENSOR_DEVICE_ATTR(temp3_min, S_IRUGO, show_temp_min,
-				set_temp_min, 2);
-static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp, NULL, 3);
-static SENSOR_DEVICE_ATTR(temp4_max, S_IRUGO, show_temp_max,
-				set_temp_max, 3);
-static SENSOR_DEVICE_ATTR(temp4_min, S_IRUGO, show_temp_min,
-				set_temp_min, 3);
-static SENSOR_DEVICE_ATTR(temp5_input, S_IRUGO, show_temp, NULL, 4);
-static SENSOR_DEVICE_ATTR(temp5_max, S_IRUGO, show_temp_max,
-				set_temp_max, 4);
-static SENSOR_DEVICE_ATTR(temp5_min, S_IRUGO, show_temp_min,
-				set_temp_min, 4);
-
-static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 14);
-static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 13);
-static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_alarm, NULL, 7);
-static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 6);
-static SENSOR_DEVICE_ATTR(temp3_min_alarm, S_IRUGO, show_alarm, NULL, 5);
-static SENSOR_DEVICE_ATTR(temp3_max_alarm, S_IRUGO, show_alarm, NULL, 4);
-static SENSOR_DEVICE_ATTR(temp4_min_alarm, S_IRUGO, show_alarm, NULL, 3);
-static SENSOR_DEVICE_ATTR(temp4_max_alarm, S_IRUGO, show_alarm, NULL, 2);
-static SENSOR_DEVICE_ATTR(temp5_min_alarm, S_IRUGO, show_alarm, NULL, 1);
-static SENSOR_DEVICE_ATTR(temp5_max_alarm, S_IRUGO, show_alarm, NULL, 0);
-
-static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
-static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
-static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
-static SENSOR_DEVICE_ATTR(temp5_fault, S_IRUGO, show_fault, NULL, 4);
-
-/* Attributes common to MAX1668, MAX1989 and MAX1805 */
-static struct attribute *max1668_attribute_common[] = {
-	&sensor_dev_attr_temp1_max.dev_attr.attr,
-	&sensor_dev_attr_temp1_min.dev_attr.attr,
-	&sensor_dev_attr_temp1_input.dev_attr.attr,
-	&sensor_dev_attr_temp2_max.dev_attr.attr,
-	&sensor_dev_attr_temp2_min.dev_attr.attr,
-	&sensor_dev_attr_temp2_input.dev_attr.attr,
-	&sensor_dev_attr_temp3_max.dev_attr.attr,
-	&sensor_dev_attr_temp3_min.dev_attr.attr,
-	&sensor_dev_attr_temp3_input.dev_attr.attr,
-
-	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp3_min_alarm.dev_attr.attr,
-
-	&sensor_dev_attr_temp2_fault.dev_attr.attr,
-	&sensor_dev_attr_temp3_fault.dev_attr.attr,
+static const struct hwmon_channel_info * const max1668_info[] = {
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
+			   HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM,
+			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
+			   HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
+			   HWMON_T_FAULT,
+			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
+			   HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
+			   HWMON_T_FAULT,
+			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
+			   HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
+			   HWMON_T_FAULT,
+			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
+			   HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
+			   HWMON_T_FAULT),
 	NULL
 };
 
-/* Attributes not present on MAX1805 */
-static struct attribute *max1668_attribute_unique[] = {
-	&sensor_dev_attr_temp4_max.dev_attr.attr,
-	&sensor_dev_attr_temp4_min.dev_attr.attr,
-	&sensor_dev_attr_temp4_input.dev_attr.attr,
-	&sensor_dev_attr_temp5_max.dev_attr.attr,
-	&sensor_dev_attr_temp5_min.dev_attr.attr,
-	&sensor_dev_attr_temp5_input.dev_attr.attr,
-
-	&sensor_dev_attr_temp4_max_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp4_min_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp5_max_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp5_min_alarm.dev_attr.attr,
-
-	&sensor_dev_attr_temp4_fault.dev_attr.attr,
-	&sensor_dev_attr_temp5_fault.dev_attr.attr,
-	NULL
+static const struct hwmon_ops max1668_hwmon_ops = {
+	.is_visible = max1668_is_visible,
+	.read = max1668_read,
+	.write = max1668_write,
 };
 
-static umode_t max1668_attribute_mode(struct kobject *kobj,
-				     struct attribute *attr, int index)
-{
-	umode_t ret = S_IRUGO;
-	if (read_only)
-		return ret;
-	if (attr == &sensor_dev_attr_temp1_max.dev_attr.attr ||
-	    attr == &sensor_dev_attr_temp2_max.dev_attr.attr ||
-	    attr == &sensor_dev_attr_temp3_max.dev_attr.attr ||
-	    attr == &sensor_dev_attr_temp4_max.dev_attr.attr ||
-	    attr == &sensor_dev_attr_temp5_max.dev_attr.attr ||
-	    attr == &sensor_dev_attr_temp1_min.dev_attr.attr ||
-	    attr == &sensor_dev_attr_temp2_min.dev_attr.attr ||
-	    attr == &sensor_dev_attr_temp3_min.dev_attr.attr ||
-	    attr == &sensor_dev_attr_temp4_min.dev_attr.attr ||
-	    attr == &sensor_dev_attr_temp5_min.dev_attr.attr)
-		ret |= S_IWUSR;
-	return ret;
-}
-
-static const struct attribute_group max1668_group_common = {
-	.attrs = max1668_attribute_common,
-	.is_visible = max1668_attribute_mode
-};
-
-static const struct attribute_group max1668_group_unique = {
-	.attrs = max1668_attribute_unique,
-	.is_visible = max1668_attribute_mode
+static const struct hwmon_chip_info max1668_chip_info = {
+	.ops = &max1668_hwmon_ops,
+	.info = max1668_info,
 };
 
 /* Return 0 if detection is successful, -ENODEV otherwise */
@@ -391,13 +287,8 @@ static int max1668_probe(struct i2c_client *client)
 
 	data->channels = (uintptr_t)i2c_get_match_data(client);
 
-	/* sysfs hooks */
-	data->groups[0] = &max1668_group_common;
-	if (data->channels == 5)
-		data->groups[1] = &max1668_group_unique;
-
-	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
-							   data, data->groups);
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
+							 &max1668_chip_info, NULL);
 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }
 
-- 
2.39.2