Re: [PATCH 07/11] hwmon: (max6650) Convert to use devm_hwmon_device_register_with_info

[Guenter Roeck <linux@roeck-us.net>]

On Tue, Apr 23, 2019 at 06:33:07AM -0700, Guenter Roeck wrote:
> Convert driver to use devm_hwmon_device_register_with_info to simplify
> the code and to reduce its size.
> 

To keep everyone up to date, I have made the changes indicated below
to the patch. Thanks to 0day and Julia Lawall for reporting the problems.

Guenter

> Cc: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
>  drivers/hwmon/max6650.c | 505 +++++++++++++++++++++++-------------------------
>  1 file changed, 244 insertions(+), 261 deletions(-)
> 
> diff --git a/drivers/hwmon/max6650.c b/drivers/hwmon/max6650.c
> index c02694d70eee..301184172ab1 100644
> --- a/drivers/hwmon/max6650.c
> +++ b/drivers/hwmon/max6650.c
> @@ -114,7 +114,6 @@ module_param(clock, int, 0444);
>  
>  struct max6650_data {
>  	struct i2c_client *client;
> -	const struct attribute_group *groups[3];
>  	struct thermal_cooling_device *cooling_dev;
>  	struct mutex update_lock;
>  	int nr_fans;
> @@ -230,26 +229,6 @@ static int max6650_set_operating_mode(struct max6650_data *data, u8 mode)
>  	return 0;
>  }
>  
> -static ssize_t fan_show(struct device *dev, struct device_attribute *devattr,
> -			char *buf)
> -{
> -	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> -	struct max6650_data *data = max6650_update_device(dev);
> -	int rpm;
> -
> -	/*
> -	 * Calculation details:
> -	 *
> -	 * Each tachometer counts over an interval given by the "count"
> -	 * register (0.25, 0.5, 1 or 2 seconds). This module assumes
> -	 * that the fans produce two pulses per revolution (this seems
> -	 * to be the most common).
> -	 */
> -
> -	rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
> -	return sprintf(buf, "%d\n", rpm);
> -}
> -
>  /*
>   * Set the fan speed to the specified RPM (or read back the RPM setting).
>   * This works in closed loop mode only. Use pwm1 for open loop speed setting.
> @@ -291,26 +270,6 @@ static ssize_t fan_show(struct device *dev, struct device_attribute *devattr,
>   * controlled.
>   */
>  
> -static ssize_t fan1_target_show(struct device *dev,
> -				struct device_attribute *devattr, char *buf)
> -{
> -	struct max6650_data *data = max6650_update_device(dev);
> -	int kscale, ktach, rpm;
> -
> -	/*
> -	 * Use the datasheet equation:
> -	 *
> -	 *    FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
> -	 *
> -	 * then multiply by 60 to give rpm.
> -	 */
> -
> -	kscale = DIV_FROM_REG(data->config);
> -	ktach = data->speed;
> -	rpm = 60 * kscale * clock / (256 * (ktach + 1));
> -	return sprintf(buf, "%d\n", rpm);
> -}
> -
>  static int max6650_set_target(struct max6650_data *data, unsigned long rpm)
>  {
>  	int kscale, ktach;
> @@ -339,183 +298,8 @@ static int max6650_set_target(struct max6650_data *data, unsigned long rpm)
>  					 data->speed);
>  }
>  
> -static ssize_t fan1_target_store(struct device *dev,
> -				 struct device_attribute *devattr,
> -				 const char *buf, size_t count)
> -{
> -	struct max6650_data *data = dev_get_drvdata(dev);
> -	unsigned long rpm;
> -	int err;
> -
> -	err = kstrtoul(buf, 10, &rpm);
> -	if (err)
> -		return err;
> -
> -	mutex_lock(&data->update_lock);
> -
> -	err = max6650_set_target(data, rpm);
> -
> -	mutex_unlock(&data->update_lock);
> -
> -	if (err < 0)
> -		return err;
> -
> -	return count;
> -}
> -
> -/*
> - * Get/set the fan speed in open loop mode using pwm1 sysfs file.
> - * Speed is given as a relative value from 0 to 255, where 255 is maximum
> - * speed. Note that this is done by writing directly to the chip's DAC,
> - * it won't change the closed loop speed set by fan1_target.
> - * Also note that due to rounding errors it is possible that you don't read
> - * back exactly the value you have set.
> - */
> -
> -static ssize_t pwm1_show(struct device *dev, struct device_attribute *devattr,
> -			 char *buf)
> -{
> -	struct max6650_data *data = max6650_update_device(dev);
> -
> -	return sprintf(buf, "%d\n", dac_to_pwm(data->dac,
> -					       data->config & MAX6650_CFG_V12));
> -}
> -
> -static ssize_t pwm1_store(struct device *dev,
> -			  struct device_attribute *devattr, const char *buf,
> -			  size_t count)
> -{
> -	struct max6650_data *data = dev_get_drvdata(dev);
> -	struct i2c_client *client = data->client;
> -	unsigned long pwm;
> -	int err;
> -	u8 dac;
> -
> -	err = kstrtoul(buf, 10, &pwm);
> -	if (err)
> -		return err;
> -
> -	pwm = clamp_val(pwm, 0, 255);
> -
> -	mutex_lock(&data->update_lock);
> -	dac = pwm_to_dac(pwm, data->config & MAX6650_CFG_V12);
> -	err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, dac);
> -	if (!err)
> -		data->dac = dac;
> -	mutex_unlock(&data->update_lock);
> -
> -	return err < 0 ? err : count;
> -}
> -
> -/*
> - * Get/Set controller mode:
> - * Possible values:
> - * 0 = Fan always on
> - * 1 = Open loop, Voltage is set according to speed, not regulated.
> - * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
> - * 3 = Fan off
> - */
> -static ssize_t pwm1_enable_show(struct device *dev,
> -				struct device_attribute *devattr, char *buf)
> -{
> -	struct max6650_data *data = max6650_update_device(dev);
> -	int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
> -	int sysfs_modes[4] = {0, 3, 2, 1};
> -
> -	return sprintf(buf, "%d\n", sysfs_modes[mode]);
> -}
> -
> -static ssize_t pwm1_enable_store(struct device *dev,
> -				 struct device_attribute *devattr,
> -				 const char *buf, size_t count)
> -{
> -	struct max6650_data *data = dev_get_drvdata(dev);
> -	unsigned long mode;
> -	int err;
> -	const u8 max6650_modes[] = {
> -		MAX6650_CFG_MODE_ON,
> -		MAX6650_CFG_MODE_OPEN_LOOP,
> -		MAX6650_CFG_MODE_CLOSED_LOOP,
> -		MAX6650_CFG_MODE_OFF,
> -		};
> -
> -	err = kstrtoul(buf, 10, &mode);
> -	if (err)
> -		return err;
> -
> -	if (mode >= ARRAY_SIZE(max6650_modes))
> -		return -EINVAL;
> -
> -	mutex_lock(&data->update_lock);
> -
> -	max6650_set_operating_mode(data, max6650_modes[mode]);
> -
> -	mutex_unlock(&data->update_lock);
> -
> -	return count;
> -}
> -
> -/*
> - * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
> - * divider. We handle this by converting between divider and counttime:
> - *
> - * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
> - *
> - * Lower values of k allow to connect a faster fan without the risk of
> - * counter overflow. The price is lower resolution. You can also set counttime
> - * using the module parameter. Note that the module parameter "prescaler" also
> - * influences the behaviour. Unfortunately, there's no sysfs attribute
> - * defined for that. See the data sheet for details.
> - */
> -
> -static ssize_t fan1_div_show(struct device *dev,
> -			     struct device_attribute *devattr, char *buf)
> -{
> -	struct max6650_data *data = max6650_update_device(dev);
> -
> -	return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
> -}
> -
> -static ssize_t fan1_div_store(struct device *dev,
> -			      struct device_attribute *devattr,
> -			      const char *buf, size_t count)
> -{
> -	struct max6650_data *data = dev_get_drvdata(dev);
> -	struct i2c_client *client = data->client;
> -	unsigned long div;
> -	int err;
> -
> -	err = kstrtoul(buf, 10, &div);
> -	if (err)
> -		return err;
> -
> -	mutex_lock(&data->update_lock);
> -	switch (div) {
> -	case 1:
> -		data->count = 0;
> -		break;
> -	case 2:
> -		data->count = 1;
> -		break;
> -	case 4:
> -		data->count = 2;
> -		break;
> -	case 8:
> -		data->count = 3;
> -		break;
> -	default:
> -		mutex_unlock(&data->update_lock);
> -		return -EINVAL;
> -	}
> -
> -	i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
> -	mutex_unlock(&data->update_lock);
> -
> -	return count;
> -}
> -
>  /*
> - * Get alarm stati:
> + * Get gpio alarm status:
>   * Possible values:
>   * 0 = no alarm
>   * 1 = alarm
> @@ -538,17 +322,6 @@ static ssize_t alarm_show(struct device *dev,
>  	return sprintf(buf, "%d\n", alarm);
>  }
>  
> -static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, 0);
> -static SENSOR_DEVICE_ATTR_RO(fan2_input, fan, 1);
> -static SENSOR_DEVICE_ATTR_RO(fan3_input, fan, 2);
> -static SENSOR_DEVICE_ATTR_RO(fan4_input, fan, 3);
> -static DEVICE_ATTR_RW(fan1_target);
> -static DEVICE_ATTR_RW(fan1_div);
> -static DEVICE_ATTR_RW(pwm1_enable);
> -static DEVICE_ATTR_RW(pwm1);
> -static SENSOR_DEVICE_ATTR_RO(fan1_max_alarm, alarm, MAX6650_ALRM_MAX);
> -static SENSOR_DEVICE_ATTR_RO(fan1_min_alarm, alarm, MAX6650_ALRM_MIN);
> -static SENSOR_DEVICE_ATTR_RO(fan1_fault, alarm, MAX6650_ALRM_TACH);
>  static SENSOR_DEVICE_ATTR_RO(gpio1_alarm, alarm, MAX6650_ALRM_GPIO1);
>  static SENSOR_DEVICE_ATTR_RO(gpio2_alarm, alarm, MAX6650_ALRM_GPIO2);
>  
> @@ -564,11 +337,8 @@ static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
>  	 */
>  
>  	devattr = container_of(a, struct device_attribute, attr);
> -	if (devattr == &sensor_dev_attr_fan1_max_alarm.dev_attr
> -	 || devattr == &sensor_dev_attr_fan1_min_alarm.dev_attr
> -	 || devattr == &sensor_dev_attr_fan1_fault.dev_attr
> -	 || devattr == &sensor_dev_attr_gpio1_alarm.dev_attr
> -	 || devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
> +	if (devattr == &sensor_dev_attr_gpio1_alarm.dev_attr ||
> +	    devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
>  		if (!(data->alarm_en & to_sensor_dev_attr(devattr)->index))
>  			return 0;
>  	}
> @@ -577,14 +347,6 @@ static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
>  }
>  
>  static struct attribute *max6650_attrs[] = {
> -	&sensor_dev_attr_fan1_input.dev_attr.attr,
> -	&dev_attr_fan1_target.attr,
> -	&dev_attr_fan1_div.attr,
> -	&dev_attr_pwm1_enable.attr,
> -	&dev_attr_pwm1.attr,
> -	&sensor_dev_attr_fan1_max_alarm.dev_attr.attr,
> -	&sensor_dev_attr_fan1_min_alarm.dev_attr.attr,
> -	&sensor_dev_attr_fan1_fault.dev_attr.attr,
>  	&sensor_dev_attr_gpio1_alarm.dev_attr.attr,
>  	&sensor_dev_attr_gpio2_alarm.dev_attr.attr,
>  	NULL
> @@ -595,21 +357,11 @@ static const struct attribute_group max6650_group = {
>  	.is_visible = max6650_attrs_visible,
>  };
>  
> -static struct attribute *max6651_attrs[] = {
> -	&sensor_dev_attr_fan2_input.dev_attr.attr,
> -	&sensor_dev_attr_fan3_input.dev_attr.attr,
> -	&sensor_dev_attr_fan4_input.dev_attr.attr,
> +static const struct attribute_group *max6650_groups[] = {
> +	&max6650_group,
>  	NULL
>  };
>  
> -static const struct attribute_group max6651_group = {
> -	.attrs = max6651_attrs,
> -};
> -
> -/*
> - * Real code
> - */
> -
>  static int max6650_init_client(struct max6650_data *data,
>  			       struct i2c_client *client)
>  {
> @@ -766,6 +518,241 @@ static void max6650_thermal_unregister(void *data)
>  }
>  #endif
>  
> +static int max6650_read(struct device *dev, enum hwmon_sensor_types type,
> +			u32 attr, int channel, long *val)
> +{
> +	struct max6650_data *data = max6650_update_device(dev);
> +	int mode;
> +
> +	switch (type) {
> +	case hwmon_pwm:
> +		switch (attr) {
> +		case hwmon_pwm_input:
> +			*val = dac_to_pwm(data->dac,
> +					  data->config & MAX6650_CFG_V12);
> +			break;
> +		case hwmon_pwm_enable:
> +			/*
> +			 * Possible values:
> +			 * 0 = Fan always on
> +			 * 1 = Open loop, Voltage is set according to speed,
> +			 *     not regulated.
> +			 * 2 = Closed loop, RPM for all fans regulated by fan1
> +			 *     tachometer
> +			 * 3 = Fan off
> +			 */
> +			mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
> +			*val = (4 - mode) & 3; /* {0 1 2 3} -> {0 3 2 1} */
> +			break;
> +		default:
> +			return -EOPNOTSUPP;
> +		}
> +		break;
> +	case hwmon_fan:
> +		switch (attr) {
> +		case hwmon_fan_input:
> +			/*
> +			 * Calculation details:
> +			 *
> +			 * Each tachometer counts over an interval given by the
> +			 * "count" register (0.25, 0.5, 1 or 2 seconds).
> +			 * The driver assumes that the fans produce two pulses
> +			 * per revolution (this seems to be the most common).
> +			 */
> +			*val = DIV_ROUND_CLOSEST(data->tach[channel] * 120,
> +						 DIV_FROM_REG(data->count));
> +			break;
> +		case hwmon_fan_div:
> +			*val = DIV_FROM_REG(data->count);
> +			break;
> +		case hwmon_fan_target:
> +			/*
> +			 * Use the datasheet equation:
> +			 *    FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
> +			 * then multiply by 60 to give rpm.
> +			 */
> +			*val = 60 * DIV_FROM_REG(data->config) * clock /
> +				(256 * (data->speed + 1));
> +			break;
> +		case hwmon_fan_min_alarm:
> +			*val = !!(data->alarm & MAX6650_ALRM_MIN);
> +			data->alarm &= ~MAX6650_ALRM_MIN;
> +			data->valid = false;
> +			break;
> +		case hwmon_fan_max_alarm:
> +			*val = !!(data->alarm & MAX6650_ALRM_MAX);
> +			data->alarm &= ~MAX6650_ALRM_MAX;
> +			data->valid = false;
> +			break;
> +		case hwmon_fan_fault:
> +			*val = !!(data->alarm & MAX6650_ALRM_TACH);
> +			data->alarm &= ~MAX6650_ALRM_TACH;
> +			data->valid = false;
> +			break;
> +		default:
> +			return -EOPNOTSUPP;
> +		}
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +	return 0;
> +}
> +
> +const u8 max6650_pwm_modes[] = {

static const max6650_pwm_modes

> +	MAX6650_CFG_MODE_ON,
> +	MAX6650_CFG_MODE_OPEN_LOOP,
> +	MAX6650_CFG_MODE_CLOSED_LOOP,
> +	MAX6650_CFG_MODE_OFF,
> +};
> +
> +static int max6650_write(struct device *dev, enum hwmon_sensor_types type,
> +			 u32 attr, int channel, long val)
> +{
> +	struct max6650_data *data = dev_get_drvdata(dev);
> +	int ret = 0;
> +	u8 reg;
> +
> +	mutex_lock(&data->update_lock);
> +
> +	switch (type) {
> +	case hwmon_pwm:
> +		switch (attr) {
> +		case hwmon_pwm_input:
> +			reg = pwm_to_dac(clamp_val(val, 0, 255),
> +					 data->config & MAX6650_CFG_V12);
> +			ret = i2c_smbus_write_byte_data(data->client,
> +							MAX6650_REG_DAC, reg);
> +			if (ret)
> +				break;
> +			data->dac = reg;
> +			break;
> +		case hwmon_pwm_enable:
> +			if (val < 0 || val >= ARRAY_SIZE(max6650_pwm_modes))
> +				return -EINVAL;
						{
				ret = -EINVAL;
				break;
			}

> +			ret = max6650_set_operating_mode(data,
> +						max6650_pwm_modes[val]);
> +			break;
> +		default:
> +			ret = -EOPNOTSUPP;
> +			break;
> +		}
> +	case hwmon_fan:
> +		switch (attr) {
> +		case hwmon_fan_div:
> +			switch (val) {
> +			case 1:
> +				reg = 0;
> +				break;
> +			case 2:
> +				reg = 1;
> +				break;
> +			case 4:
> +				reg = 2;
> +				break;
> +			case 8:
> +				reg = 3;
> +				break;
> +			default:
> +				ret = -EINVAL;
> +				goto error;
> +			}
> +			ret = i2c_smbus_write_byte_data(data->client,
> +							MAX6650_REG_COUNT, reg);
> +			if (ret)
> +				break;
> +			data->count = reg;
> +			break;
> +		case hwmon_fan_target:
> +			if (val < 0) {
> +				ret = -EINVAL;
> +				break;
> +			}
> +			ret = max6650_set_target(data, val);
> +			break;
> +		default:
> +			ret = -EOPNOTSUPP;
> +			break;
> +		}
> +		break;
> +	default:
> +		ret = -EOPNOTSUPP;
> +		break;
> +	}
> +
> +error:
> +	mutex_unlock(&data->update_lock);
> +	return ret;
> +}
> +
> +static umode_t max6650_is_visible(const void *_data,
> +				  enum hwmon_sensor_types type, u32 attr,
> +				  int channel)
> +{
> +	const struct max6650_data *data = _data;
> +
> +	if (channel && (channel >= data->nr_fans || type != hwmon_fan))
> +		return 0;
> +
> +	switch (type) {
> +	case hwmon_fan:
> +		switch (attr) {
> +		case hwmon_fan_input:
> +			return 0444;
> +		case hwmon_fan_target:
> +		case hwmon_fan_div:
> +			return 0644;
> +		case hwmon_fan_min_alarm:
> +			if (data->alarm_en & MAX6650_ALRM_MIN)
> +				return 0444;
> +			break;
> +		case hwmon_fan_max_alarm:
> +			if (data->alarm_en & MAX6650_ALRM_MAX)
> +				return 0444;
> +			break;
> +		case hwmon_fan_fault:
> +			if (data->alarm_en & MAX6650_ALRM_TACH)
> +				return 0444;
> +			break;
> +		default:
> +			break;
> +		}
> +		break;
> +	case hwmon_pwm:
> +		switch (attr) {
> +		case hwmon_pwm_input:
> +		case hwmon_pwm_enable:
> +			return 0644;
> +		default:
> +			break;
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +	return 0;
> +}
> +
> +static const struct hwmon_channel_info *max6650_info[] = {
> +	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_DIV |
> +			   HWMON_F_MIN_ALARM | HWMON_F_MAX_ALARM |
> +			   HWMON_F_FAULT,
> +			   HWMON_F_INPUT, HWMON_F_INPUT, HWMON_F_INPUT),
> +	HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_ENABLE),
> +	NULL
> +};
> +
> +static const struct hwmon_ops max6650_hwmon_ops = {
> +	.read = max6650_read,
> +	.write = max6650_write,
> +	.is_visible = max6650_is_visible,
> +};
> +
> +static const struct hwmon_chip_info max6650_chip_info = {
> +	.ops = &max6650_hwmon_ops,
> +	.info = max6650_info,
> +};
> +
>  static int max6650_probe(struct i2c_client *client,
>  			 const struct i2c_device_id *id)
>  {
> @@ -792,14 +779,10 @@ static int max6650_probe(struct i2c_client *client,
>  	if (err)
>  		return err;
>  
> -	data->groups[0] = &max6650_group;
> -	/* 3 additional fan inputs for the MAX6651 */
> -	if (data->nr_fans == 4)
> -		data->groups[1] = &max6651_group;
> -
> -	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,
> +							 &max6650_chip_info,
> +							 max6650_groups);
>  	err = PTR_ERR_OR_ZERO(hwmon_dev);
>  	if (err)
>  		return err;