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Sender: Guenter Roeck <groeck7@gmail.com>
Date: Thu, 2 May 2024 13:01:26 -0700
From: Guenter Roeck <linux@roeck-us.net>
To: Naresh Solanki <naresh.solanki@9elements.com>
Cc: Jean Delvare <jdelvare@suse.com>, linux-hwmon@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] hwmon (max6639): Use regmap
Message-ID: <78af0dfa-7021-4d20-8ea4-69e60ed1263e@roeck-us.net>
References: <20240502183604.1216576-1-naresh.solanki@9elements.com>
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In-Reply-To: <20240502183604.1216576-1-naresh.solanki@9elements.com>

On Fri, May 03, 2024 at 12:06:02AM +0530, Naresh Solanki wrote:
> Add regmap support & remove local caching.
> 
> Signed-off-by: Naresh Solanki <naresh.solanki@9elements.com>

Almost there. Couple of minor comments.

Thanks,
Guenter

> ---
> Changes in V3:
> - Remove mutex lock
> - Remove caching of variable pwm in max6639_data
> - Use regmap_write_bits in suspend & resume
> - Remove error check for data in attrube show/store functions.
> - Remove goto
> 
> Changes in V2:
> - Remove local caching in max6639_data struct.
> - Use define MAX6639_NDEV wherever possible
> ---
>  drivers/hwmon/Kconfig   |   1 +
>  drivers/hwmon/max6639.c | 334 +++++++++++++++++-----------------------
>  2 files changed, 145 insertions(+), 190 deletions(-)
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index bafc0058c728..e14ae18a973b 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1233,6 +1233,7 @@ config SENSORS_MAX6621
>  config SENSORS_MAX6639
>  	tristate "Maxim MAX6639 sensor chip"
>  	depends on I2C
> +	select REGMAP_I2C
>  	help
>  	  If you say yes here you get support for the MAX6639
>  	  sensor chips.
> diff --git a/drivers/hwmon/max6639.c b/drivers/hwmon/max6639.c
> index 5dd0349e8bd0..f914f1500c96 100644
> --- a/drivers/hwmon/max6639.c
> +++ b/drivers/hwmon/max6639.c
> @@ -20,6 +20,7 @@
>  #include <linux/err.h>
>  #include <linux/mutex.h>
>  #include <linux/platform_data/max6639.h>
> +#include <linux/regmap.h>
>  
>  /* Addresses to scan */
>  static const unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };
> @@ -57,6 +58,8 @@ static const unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };
>  
>  #define MAX6639_FAN_CONFIG3_THERM_FULL_SPEED	0x40
>  
> +#define MAX6639_NDEV				2
> +

FWIW, the define is only used once. I'd suggest to drop it because it
isn't really that valuable. I'll accept it if you really want it, but
then please rename it to something like MAX6639_NUM_CHANNELS do
better reflect its meaning.

>  static const int rpm_ranges[] = { 2000, 4000, 8000, 16000 };
>  
>  #define FAN_FROM_REG(val, rpm_range)	((val) == 0 || (val) == 255 ? \
> @@ -67,22 +70,7 @@ static const int rpm_ranges[] = { 2000, 4000, 8000, 16000 };
>   * Client data (each client gets its own)
>   */
>  struct max6639_data {
> -	struct i2c_client *client;
> -	struct mutex update_lock;
> -	bool valid;		/* true if following fields are valid */
> -	unsigned long last_updated;	/* In jiffies */
> -
> -	/* Register values sampled regularly */
> -	u16 temp[2];		/* Temperature, in 1/8 C, 0..255 C */
> -	bool temp_fault[2];	/* Detected temperature diode failure */
> -	u8 fan[2];		/* Register value: TACH count for fans >=30 */
> -	u8 status;		/* Detected channel alarms and fan failures */
> -
> -	/* Register values only written to */
> -	u8 pwm[2];		/* Register value: Duty cycle 0..120 */
> -	u8 temp_therm[2];	/* THERM Temperature, 0..255 C (->_max) */
> -	u8 temp_alert[2];	/* ALERT Temperature, 0..255 C (->_crit) */
> -	u8 temp_ot[2];		/* OT Temperature, 0..255 C (->_emergency) */
> +	struct regmap *regmap;
>  
>  	/* Register values initialized only once */
>  	u8 ppr;			/* Pulses per rotation 0..3 for 1..4 ppr */
> @@ -92,90 +80,43 @@ struct max6639_data {
>  	struct regulator *reg;
>  };
>  
> -static struct max6639_data *max6639_update_device(struct device *dev)
> -{
> -	struct max6639_data *data = dev_get_drvdata(dev);
> -	struct i2c_client *client = data->client;
> -	struct max6639_data *ret = data;
> -	int i;
> -	int status_reg;
> -
> -	mutex_lock(&data->update_lock);
> -
> -	if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
> -		int res;
> -
> -		dev_dbg(&client->dev, "Starting max6639 update\n");
> -
> -		status_reg = i2c_smbus_read_byte_data(client,
> -						      MAX6639_REG_STATUS);
> -		if (status_reg < 0) {
> -			ret = ERR_PTR(status_reg);
> -			goto abort;
> -		}
> -
> -		data->status = status_reg;
> -
> -		for (i = 0; i < 2; i++) {
> -			res = i2c_smbus_read_byte_data(client,
> -					MAX6639_REG_FAN_CNT(i));
> -			if (res < 0) {
> -				ret = ERR_PTR(res);
> -				goto abort;
> -			}
> -			data->fan[i] = res;
> -
> -			res = i2c_smbus_read_byte_data(client,
> -					MAX6639_REG_TEMP_EXT(i));
> -			if (res < 0) {
> -				ret = ERR_PTR(res);
> -				goto abort;
> -			}
> -			data->temp[i] = res >> 5;
> -			data->temp_fault[i] = res & 0x01;
> -
> -			res = i2c_smbus_read_byte_data(client,
> -					MAX6639_REG_TEMP(i));
> -			if (res < 0) {
> -				ret = ERR_PTR(res);
> -				goto abort;
> -			}
> -			data->temp[i] |= res << 3;
> -		}
> -
> -		data->last_updated = jiffies;
> -		data->valid = true;
> -	}
> -abort:
> -	mutex_unlock(&data->update_lock);
> -
> -	return ret;
> -}
> -
>  static ssize_t temp_input_show(struct device *dev,
>  			       struct device_attribute *dev_attr, char *buf)
>  {
>  	long temp;
> -	struct max6639_data *data = max6639_update_device(dev);
> +	struct max6639_data *data = dev_get_drvdata(dev);
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
> +	unsigned int val;
> +	int res;
>  
> -	if (IS_ERR(data))
> -		return PTR_ERR(data);
> +	res = regmap_read(data->regmap, MAX6639_REG_TEMP_EXT(attr->index), &val);
> +	if (res < 0)
> +		return res;
> +
> +	temp = val >> 5;
> +	res = regmap_read(data->regmap, MAX6639_REG_TEMP(attr->index), &val);
> +	if (res < 0)
> +		return res;
> +

It might be worthwhile adding a comment explaining that MAX6639_REG_TEMP
won't change for at least 250ms after reading MAX6639_REG_TEMP_EXT,
making a lock unnecessary.

> +	temp |= val << 3;
> +	temp *= 125;
>  
> -	temp = data->temp[attr->index] * 125;
>  	return sprintf(buf, "%ld\n", temp);
>  }
>  
>  static ssize_t temp_fault_show(struct device *dev,
>  			       struct device_attribute *dev_attr, char *buf)
>  {
> -	struct max6639_data *data = max6639_update_device(dev);
> +	struct max6639_data *data = dev_get_drvdata(dev);
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
> +	unsigned int val;
> +	int res;
>  
> -	if (IS_ERR(data))
> -		return PTR_ERR(data);
> +	res = regmap_read(data->regmap, MAX6639_REG_TEMP_EXT(attr->index), &val);
> +	if (res < 0)
> +		return res;
>  
> -	return sprintf(buf, "%d\n", data->temp_fault[attr->index]);
> +	return sprintf(buf, "%d\n", val & 1);
>  }
>  
>  static ssize_t temp_max_show(struct device *dev,
> @@ -183,8 +124,14 @@ static ssize_t temp_max_show(struct device *dev,
>  {
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
>  	struct max6639_data *data = dev_get_drvdata(dev);
> +	unsigned int val;
> +	int res;
>  
> -	return sprintf(buf, "%d\n", (data->temp_therm[attr->index] * 1000));
> +	res = regmap_read(data->regmap, MAX6639_REG_THERM_LIMIT(attr->index), &val);
> +	if (res < 0)
> +		return res;
> +
> +	return sprintf(buf, "%d\n", (val * 1000));
>  }
>  
>  static ssize_t temp_max_store(struct device *dev,
> @@ -193,7 +140,6 @@ static ssize_t temp_max_store(struct device *dev,
>  {
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
>  	struct max6639_data *data = dev_get_drvdata(dev);
> -	struct i2c_client *client = data->client;
>  	unsigned long val;
>  	int res;
>  
> @@ -201,12 +147,8 @@ static ssize_t temp_max_store(struct device *dev,
>  	if (res)
>  		return res;
>  
> -	mutex_lock(&data->update_lock);
> -	data->temp_therm[attr->index] = TEMP_LIMIT_TO_REG(val);
> -	i2c_smbus_write_byte_data(client,
> -				  MAX6639_REG_THERM_LIMIT(attr->index),
> -				  data->temp_therm[attr->index]);
> -	mutex_unlock(&data->update_lock);
> +	regmap_write(data->regmap, MAX6639_REG_THERM_LIMIT(attr->index),
> +		     TEMP_LIMIT_TO_REG(val));
>  	return count;
>  }
>  
> @@ -215,8 +157,14 @@ static ssize_t temp_crit_show(struct device *dev,
>  {
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
>  	struct max6639_data *data = dev_get_drvdata(dev);
> +	unsigned int val;
> +	int res;
> +
> +	res = regmap_read(data->regmap, MAX6639_REG_ALERT_LIMIT(attr->index), &val);
> +	if (res < 0)
> +		return res;
>  
> -	return sprintf(buf, "%d\n", (data->temp_alert[attr->index] * 1000));
> +	return sprintf(buf, "%d\n", (val * 1000));
>  }
>  
>  static ssize_t temp_crit_store(struct device *dev,
> @@ -225,7 +173,6 @@ static ssize_t temp_crit_store(struct device *dev,
>  {
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
>  	struct max6639_data *data = dev_get_drvdata(dev);
> -	struct i2c_client *client = data->client;
>  	unsigned long val;
>  	int res;
>  
> @@ -233,12 +180,8 @@ static ssize_t temp_crit_store(struct device *dev,
>  	if (res)
>  		return res;
>  
> -	mutex_lock(&data->update_lock);
> -	data->temp_alert[attr->index] = TEMP_LIMIT_TO_REG(val);
> -	i2c_smbus_write_byte_data(client,
> -				  MAX6639_REG_ALERT_LIMIT(attr->index),
> -				  data->temp_alert[attr->index]);
> -	mutex_unlock(&data->update_lock);
> +	regmap_write(data->regmap, MAX6639_REG_ALERT_LIMIT(attr->index),
> +		     TEMP_LIMIT_TO_REG(val));
>  	return count;
>  }
>  
> @@ -248,8 +191,14 @@ static ssize_t temp_emergency_show(struct device *dev,
>  {
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
>  	struct max6639_data *data = dev_get_drvdata(dev);
> +	unsigned int val;
> +	int res;
> +
> +	res = regmap_read(data->regmap, MAX6639_REG_OT_LIMIT(attr->index), &val);
> +	if (res < 0)
> +		return res;
>  
> -	return sprintf(buf, "%d\n", (data->temp_ot[attr->index] * 1000));
> +	return sprintf(buf, "%d\n", (val * 1000));
>  }
>  
>  static ssize_t temp_emergency_store(struct device *dev,
> @@ -258,7 +207,6 @@ static ssize_t temp_emergency_store(struct device *dev,
>  {
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
>  	struct max6639_data *data = dev_get_drvdata(dev);
> -	struct i2c_client *client = data->client;
>  	unsigned long val;
>  	int res;
>  
> @@ -266,12 +214,8 @@ static ssize_t temp_emergency_store(struct device *dev,
>  	if (res)
>  		return res;
>  
> -	mutex_lock(&data->update_lock);
> -	data->temp_ot[attr->index] = TEMP_LIMIT_TO_REG(val);
> -	i2c_smbus_write_byte_data(client,
> -				  MAX6639_REG_OT_LIMIT(attr->index),
> -				  data->temp_ot[attr->index]);
> -	mutex_unlock(&data->update_lock);
> +	regmap_write(data->regmap, MAX6639_REG_OT_LIMIT(attr->index), TEMP_LIMIT_TO_REG(val));
> +
>  	return count;
>  }
>  
> @@ -280,8 +224,14 @@ static ssize_t pwm_show(struct device *dev, struct device_attribute *dev_attr,
>  {
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
>  	struct max6639_data *data = dev_get_drvdata(dev);
> +	unsigned int val;
> +	int res;
> +
> +	res = regmap_read(data->regmap, MAX6639_REG_TARGTDUTY(attr->index), &val);
> +	if (res < 0)
> +		return res;
>  
> -	return sprintf(buf, "%d\n", data->pwm[attr->index] * 255 / 120);
> +	return sprintf(buf, "%d\n", val * 255 / 120);
>  }
>  
>  static ssize_t pwm_store(struct device *dev,
> @@ -290,7 +240,6 @@ static ssize_t pwm_store(struct device *dev,
>  {
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
>  	struct max6639_data *data = dev_get_drvdata(dev);
> -	struct i2c_client *client = data->client;
>  	unsigned long val;
>  	int res;
>  
> @@ -300,38 +249,39 @@ static ssize_t pwm_store(struct device *dev,
>  
>  	val = clamp_val(val, 0, 255);
>  
> -	mutex_lock(&data->update_lock);
> -	data->pwm[attr->index] = (u8)(val * 120 / 255);
> -	i2c_smbus_write_byte_data(client,
> -				  MAX6639_REG_TARGTDUTY(attr->index),
> -				  data->pwm[attr->index]);
> -	mutex_unlock(&data->update_lock);
> +	regmap_write(data->regmap, MAX6639_REG_TARGTDUTY(attr->index), val * 120 / 255);
> +
>  	return count;
>  }
>  
>  static ssize_t fan_input_show(struct device *dev,
>  			      struct device_attribute *dev_attr, char *buf)
>  {
> -	struct max6639_data *data = max6639_update_device(dev);
> +	struct max6639_data *data = dev_get_drvdata(dev);
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
> +	unsigned int val;
> +	int res;
>  
> -	if (IS_ERR(data))
> -		return PTR_ERR(data);
> +	res = regmap_read(data->regmap, MAX6639_REG_FAN_CNT(attr->index), &val);
> +	if (res < 0)
> +		return res;
>  
> -	return sprintf(buf, "%d\n", FAN_FROM_REG(data->fan[attr->index],
> -		       data->rpm_range));
> +	return sprintf(buf, "%d\n", FAN_FROM_REG(val, data->rpm_range));
>  }
>  
>  static ssize_t alarm_show(struct device *dev,
>  			  struct device_attribute *dev_attr, char *buf)
>  {
> -	struct max6639_data *data = max6639_update_device(dev);
> +	struct max6639_data *data = dev_get_drvdata(dev);
>  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
> +	unsigned int val;
> +	int res;
>  
> -	if (IS_ERR(data))
> -		return PTR_ERR(data);
> +	res = regmap_read(data->regmap, MAX6639_REG_STATUS, &val);
> +	if (res < 0)
> +		return res;
>  
> -	return sprintf(buf, "%d\n", !!(data->status & (1 << attr->index)));
> +	return sprintf(buf, "%d\n", !!(val & (1 << attr->index)));
>  }
>  
>  static SENSOR_DEVICE_ATTR_RO(temp1_input, temp_input, 0);
> @@ -401,6 +351,11 @@ static int rpm_range_to_reg(int range)
>  	return 1; /* default: 4000 RPM */
>  }
>  
> +static int max6639_set_ppr(struct max6639_data *data, u8 channel, u8 ppr)
> +{
> +	return regmap_write(data->regmap, MAX6639_REG_FAN_PPR(channel), ppr << 6);
> +}
> +
>  static int max6639_init_client(struct i2c_client *client,
>  			       struct max6639_data *data)
>  {
> @@ -408,94 +363,76 @@ static int max6639_init_client(struct i2c_client *client,
>  		dev_get_platdata(&client->dev);
>  	int i;
>  	int rpm_range = 1; /* default: 4000 RPM */
> -	int err;
> +	int err, ppr;
>  
>  	/* Reset chip to default values, see below for GCONFIG setup */
> -	err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
> -				  MAX6639_GCONFIG_POR);
> +	err = regmap_write(data->regmap, MAX6639_REG_GCONFIG, MAX6639_GCONFIG_POR);
>  	if (err)
> -		goto exit;
> +		return err;
>  
>  	/* Fans pulse per revolution is 2 by default */
>  	if (max6639_info && max6639_info->ppr > 0 &&
>  			max6639_info->ppr < 5)
> -		data->ppr = max6639_info->ppr;
> +		ppr = max6639_info->ppr;
>  	else
> -		data->ppr = 2;
> -	data->ppr -= 1;
> +		ppr = 2;
> +	ppr -= 1;
>  
>  	if (max6639_info)
>  		rpm_range = rpm_range_to_reg(max6639_info->rpm_range);
>  	data->rpm_range = rpm_range;
>  
> -	for (i = 0; i < 2; i++) {
> +	for (i = 0; i < MAX6639_NDEV; i++) {
>  
>  		/* Set Fan pulse per revolution */
> -		err = i2c_smbus_write_byte_data(client,
> -				MAX6639_REG_FAN_PPR(i),
> -				data->ppr << 6);
> +		err = max6639_set_ppr(data, i, ppr);
>  		if (err)
> -			goto exit;
> +			return err;
>  
>  		/* Fans config PWM, RPM */
> -		err = i2c_smbus_write_byte_data(client,
> -			MAX6639_REG_FAN_CONFIG1(i),
> -			MAX6639_FAN_CONFIG1_PWM | rpm_range);
> +		err = regmap_write(data->regmap, MAX6639_REG_FAN_CONFIG1(i),
> +				   MAX6639_FAN_CONFIG1_PWM | rpm_range);
>  		if (err)
> -			goto exit;
> +			return err;
>  
>  		/* Fans PWM polarity high by default */
>  		if (max6639_info && max6639_info->pwm_polarity == 0)
> -			err = i2c_smbus_write_byte_data(client,
> -				MAX6639_REG_FAN_CONFIG2a(i), 0x00);
> +			err = regmap_write(data->regmap, MAX6639_REG_FAN_CONFIG2a(i), 0x00);
>  		else
> -			err = i2c_smbus_write_byte_data(client,
> -				MAX6639_REG_FAN_CONFIG2a(i), 0x02);
> +			err = regmap_write(data->regmap, MAX6639_REG_FAN_CONFIG2a(i), 0x02);
>  		if (err)
> -			goto exit;
> +			return err;
>  
>  		/*
>  		 * /THERM full speed enable,
>  		 * PWM frequency 25kHz, see also GCONFIG below
>  		 */
> -		err = i2c_smbus_write_byte_data(client,
> -			MAX6639_REG_FAN_CONFIG3(i),
> -			MAX6639_FAN_CONFIG3_THERM_FULL_SPEED | 0x03);
> +		err = regmap_write(data->regmap, MAX6639_REG_FAN_CONFIG3(i),
> +				   MAX6639_FAN_CONFIG3_THERM_FULL_SPEED | 0x03);
>  		if (err)
> -			goto exit;
> +			return err;
>  
>  		/* Max. temp. 80C/90C/100C */
> -		data->temp_therm[i] = 80;
> -		data->temp_alert[i] = 90;
> -		data->temp_ot[i] = 100;
> -		err = i2c_smbus_write_byte_data(client,
> -				MAX6639_REG_THERM_LIMIT(i),
> -				data->temp_therm[i]);
> +		err = regmap_write(data->regmap, MAX6639_REG_THERM_LIMIT(i), 80);
>  		if (err)
> -			goto exit;
> -		err = i2c_smbus_write_byte_data(client,
> -				MAX6639_REG_ALERT_LIMIT(i),
> -				data->temp_alert[i]);
> +			return err;
> +		err = regmap_write(data->regmap, MAX6639_REG_ALERT_LIMIT(i), 90);
>  		if (err)
> -			goto exit;
> -		err = i2c_smbus_write_byte_data(client,
> -				MAX6639_REG_OT_LIMIT(i), data->temp_ot[i]);
> +			return err;
> +		err = regmap_write(data->regmap, MAX6639_REG_OT_LIMIT(i), 100);
>  		if (err)
> -			goto exit;
> +			return err;
>  
>  		/* PWM 120/120 (i.e. 100%) */
> -		data->pwm[i] = 120;
> -		err = i2c_smbus_write_byte_data(client,
> -				MAX6639_REG_TARGTDUTY(i), data->pwm[i]);
> +		err = regmap_write(data->regmap, MAX6639_REG_TARGTDUTY(i), 120);
>  		if (err)
> -			goto exit;
> +			return err;
>  	}
>  	/* Start monitoring */
> -	err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
> -		MAX6639_GCONFIG_DISABLE_TIMEOUT | MAX6639_GCONFIG_CH2_LOCAL |
> -		MAX6639_GCONFIG_PWM_FREQ_HI);
> -exit:
> -	return err;
> +	return regmap_write(data->regmap, MAX6639_REG_GCONFIG,
> +			    MAX6639_GCONFIG_DISABLE_TIMEOUT | MAX6639_GCONFIG_CH2_LOCAL |
> +			    MAX6639_GCONFIG_PWM_FREQ_HI);
> +
>  }
>  
>  /* Return 0 if detection is successful, -ENODEV otherwise */
> @@ -524,6 +461,30 @@ static void max6639_regulator_disable(void *data)
>  	regulator_disable(data);
>  }
>  
> +static bool max6639_regmap_is_volatile(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case MAX6639_REG_TEMP(0):
> +	case MAX6639_REG_TEMP_EXT(0):
> +	case MAX6639_REG_TEMP(1):
> +	case MAX6639_REG_TEMP_EXT(1):
> +	case MAX6639_REG_STATUS:
> +	case MAX6639_REG_FAN_CNT(0):
> +	case MAX6639_REG_FAN_CNT(1):

MAX6639_REG_TARGTDUTY() is also volatile.

> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static const struct regmap_config max6639_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = MAX6639_REG_DEVREV,
> +	.cache_type = REGCACHE_MAPLE,
> +	.volatile_reg = max6639_regmap_is_volatile,
> +};
> +
>  static int max6639_probe(struct i2c_client *client)
>  {
>  	struct device *dev = &client->dev;
> @@ -535,7 +496,11 @@ static int max6639_probe(struct i2c_client *client)
>  	if (!data)
>  		return -ENOMEM;
>  
> -	data->client = client;
> +	data->regmap = devm_regmap_init_i2c(client, &max6639_regmap_config);
> +	if (IS_ERR(data->regmap))
> +		return dev_err_probe(dev,
> +				     PTR_ERR(data->regmap),
> +				     "regmap initialization failed\n");
>  
>  	data->reg = devm_regulator_get_optional(dev, "fan");
>  	if (IS_ERR(data->reg)) {
> @@ -558,8 +523,6 @@ static int max6639_probe(struct i2c_client *client)
>  		}
>  	}
>  
> -	mutex_init(&data->update_lock);
> -
>  	/* Initialize the max6639 chip */
>  	err = max6639_init_client(client, data);
>  	if (err < 0)
> @@ -573,23 +536,18 @@ static int max6639_probe(struct i2c_client *client)
>  
>  static int max6639_suspend(struct device *dev)
>  {
> -	struct i2c_client *client = to_i2c_client(dev);
>  	struct max6639_data *data = dev_get_drvdata(dev);
> -	int ret = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
> -
> -	if (ret < 0)
> -		return ret;
> +	int ret;

/home/groeck/src/max6639/max6639.c: In function ‘max6639_suspend’:
/home/groeck/src/max6639/max6639.c:540:13: warning: unused variable ‘ret’

>  
>  	if (data->reg)
>  		regulator_disable(data->reg);
>  
> -	return i2c_smbus_write_byte_data(client,
> -			MAX6639_REG_GCONFIG, ret | MAX6639_GCONFIG_STANDBY);
> +	return regmap_write_bits(data->regmap, MAX6639_REG_GCONFIG, MAX6639_GCONFIG_STANDBY,
> +				 MAX6639_GCONFIG_STANDBY);
>  }
>  
>  static int max6639_resume(struct device *dev)
>  {
> -	struct i2c_client *client = to_i2c_client(dev);
>  	struct max6639_data *data = dev_get_drvdata(dev);
>  	int ret;
>  
> @@ -601,12 +559,8 @@ static int max6639_resume(struct device *dev)
>  		}
>  	}
>  
> -	ret = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
> -	if (ret < 0)
> -		return ret;
> -
> -	return i2c_smbus_write_byte_data(client,
> -			MAX6639_REG_GCONFIG, ret & ~MAX6639_GCONFIG_STANDBY);
> +	return regmap_write_bits(data->regmap, MAX6639_REG_GCONFIG, MAX6639_GCONFIG_STANDBY,
> +				 ~MAX6639_GCONFIG_STANDBY);
>  }
>  
>  static const struct i2c_device_id max6639_id[] = {
> 
> base-commit: 1d4d6733594d407e54153b8e031ba6356ceba81e
> -- 
> 2.42.0
> 
>