Date:   Fri, 2 Dec 2016 07:23:45 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Michael Walle <michael@...le.cc>, linux-hwmon@...r.kernel.org
Cc:     Jean Delvare <jdelvare@...e.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] hwmon: adt7411: add min, max and alarm attributes

Hi Michael,

On 12/02/2016 06:26 AM, Michael Walle wrote:
> This patch adds support for the min, max and alarm attributes of the
> voltage and temperature channels. Additionally, the temp2_fault attribute
> is supported which indicates a fault of the external temperature diode.
>
> Signed-off-by: Michael Walle <michael@...le.cc>

Mostly looks good, except for a couple of overflow issues.

Thanks,
Guenter

> ---
> v2:
>  - use BIT()
>  - new function adt7411_write_in_vdd()
>  - add missing "return 0" in read_in_vdd() for hwmon_in_max
>  - add missing "default" case in read_temp_alarm()
>  - remove uneeded "val + 0x100" statement
>  - fix AIN2 visibility
>
>  drivers/hwmon/adt7411.c | 361 ++++++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 316 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/hwmon/adt7411.c b/drivers/hwmon/adt7411.c
> index 2f44cdc..37e3b96 100644
> --- a/drivers/hwmon/adt7411.c
> +++ b/drivers/hwmon/adt7411.c
> @@ -21,6 +21,21 @@
>  #include <linux/hwmon-sysfs.h>
>  #include <linux/slab.h>
>
> +#define ADT7411_REG_STAT_1			0x00
> +#define ADT7411_STAT_1_INT_TEMP_HIGH		BIT(0)
> +#define ADT7411_STAT_1_INT_TEMP_LOW		BIT(1)
> +#define ADT7411_STAT_1_EXT_TEMP_HIGH_AIN1	BIT(2)
> +#define ADT7411_STAT_1_EXT_TEMP_LOW		BIT(3)
> +#define ADT7411_STAT_1_EXT_TEMP_FAULT		BIT(4)
> +#define ADT7411_STAT_1_AIN2			BIT(5)
> +#define ADT7411_STAT_1_AIN3			BIT(6)
> +#define ADT7411_STAT_1_AIN4			BIT(7)
> +#define ADT7411_REG_STAT_2			0x01
> +#define ADT7411_STAT_2_AIN5			BIT(0)
> +#define ADT7411_STAT_2_AIN6			BIT(1)
> +#define ADT7411_STAT_2_AIN7			BIT(2)
> +#define ADT7411_STAT_2_AIN8			BIT(3)
> +#define ADT7411_STAT_2_VDD			BIT(4)
>  #define ADT7411_REG_INT_TEMP_VDD_LSB		0x03
>  #define ADT7411_REG_EXT_TEMP_AIN14_LSB		0x04
>  #define ADT7411_REG_VDD_MSB			0x06
> @@ -28,20 +43,31 @@
>  #define ADT7411_REG_EXT_TEMP_AIN1_MSB		0x08
>
>  #define ADT7411_REG_CFG1			0x18
> -#define ADT7411_CFG1_START_MONITOR		(1 << 0)
> -#define ADT7411_CFG1_RESERVED_BIT1		(1 << 1)
> -#define ADT7411_CFG1_EXT_TDM			(1 << 2)
> -#define ADT7411_CFG1_RESERVED_BIT3		(1 << 3)
> +#define ADT7411_CFG1_START_MONITOR		BIT(0)
> +#define ADT7411_CFG1_RESERVED_BIT1		BIT(1)
> +#define ADT7411_CFG1_EXT_TDM			BIT(2)
> +#define ADT7411_CFG1_RESERVED_BIT3		BIT(3)
>
>  #define ADT7411_REG_CFG2			0x19
> -#define ADT7411_CFG2_DISABLE_AVG		(1 << 5)
> +#define ADT7411_CFG2_DISABLE_AVG		BIT(5)
>
>  #define ADT7411_REG_CFG3			0x1a
> -#define ADT7411_CFG3_ADC_CLK_225		(1 << 0)
> -#define ADT7411_CFG3_RESERVED_BIT1		(1 << 1)
> -#define ADT7411_CFG3_RESERVED_BIT2		(1 << 2)
> -#define ADT7411_CFG3_RESERVED_BIT3		(1 << 3)
> -#define ADT7411_CFG3_REF_VDD			(1 << 4)
> +#define ADT7411_CFG3_ADC_CLK_225		BIT(0)
> +#define ADT7411_CFG3_RESERVED_BIT1		BIT(1)
> +#define ADT7411_CFG3_RESERVED_BIT2		BIT(2)
> +#define ADT7411_CFG3_RESERVED_BIT3		BIT(3)
> +#define ADT7411_CFG3_REF_VDD			BIT(4)
> +
> +#define ADT7411_REG_VDD_HIGH			0x23
> +#define ADT7411_REG_VDD_LOW			0x24
> +#define ADT7411_REG_TEMP_HIGH(nr)		(0x25 + 2 * (nr))
> +#define ADT7411_REG_TEMP_LOW(nr)		(0x26 + 2 * (nr))
> +#define ADT7411_REG_IN_HIGH(nr)		((nr) > 1 \
> +						  ? 0x2b + 2 * ((nr)-2) \
> +						  : 0x27)
> +#define ADT7411_REG_IN_LOW(nr)			((nr) > 1 \
> +						  ? 0x2c + 2 * ((nr)-2) \
> +						  : 0x28)
>
>  #define ADT7411_REG_DEVICE_ID			0x4d
>  #define ADT7411_REG_MANUFACTURER_ID		0x4e
> @@ -51,6 +77,30 @@
>
>  static const unsigned short normal_i2c[] = { 0x48, 0x4a, 0x4b, I2C_CLIENT_END };
>
> +static const u8 adt7411_in_alarm_reg[] = {
> +	ADT7411_REG_STAT_2,
> +	ADT7411_REG_STAT_1,
> +	ADT7411_REG_STAT_1,
> +	ADT7411_REG_STAT_1,
> +	ADT7411_REG_STAT_1,
> +	ADT7411_REG_STAT_2,
> +	ADT7411_REG_STAT_2,
> +	ADT7411_REG_STAT_2,
> +	ADT7411_REG_STAT_2,
> +};
> +
> +static const u8 adt7411_in_alarm_bits[] = {
> +	ADT7411_STAT_2_VDD,
> +	ADT7411_STAT_1_EXT_TEMP_HIGH_AIN1,
> +	ADT7411_STAT_1_AIN2,
> +	ADT7411_STAT_1_AIN3,
> +	ADT7411_STAT_1_AIN4,
> +	ADT7411_STAT_2_AIN5,
> +	ADT7411_STAT_2_AIN6,
> +	ADT7411_STAT_2_AIN7,
> +	ADT7411_STAT_2_AIN8,
> +};
> +
>  struct adt7411_data {
>  	struct mutex device_lock;	/* for "atomic" device accesses */
>  	struct mutex update_lock;
> @@ -165,6 +215,19 @@ static struct attribute *adt7411_attrs[] = {
>  };
>  ATTRIBUTE_GROUPS(adt7411);
>
> +static int adt7411_read_in_alarm(struct device *dev, int channel, long *val)
> +{
> +	struct adt7411_data *data = dev_get_drvdata(dev);
> +	struct i2c_client *client = data->client;
> +	int ret;
> +
> +	ret = i2c_smbus_read_byte_data(client, adt7411_in_alarm_reg[channel]);
> +	if (ret < 0)
> +		return ret;
> +	*val = !!(ret & adt7411_in_alarm_bits[channel]);
> +	return 0;
> +}
> +
>  static int adt7411_read_in_vdd(struct device *dev, u32 attr, long *val)
>  {
>  	struct adt7411_data *data = dev_get_drvdata(dev);
> @@ -179,32 +242,41 @@ static int adt7411_read_in_vdd(struct device *dev, u32 attr, long *val)
>  			return ret;
>  		*val = ret * 7000 / 1024;
>  		return 0;
> +	case hwmon_in_min:
> +		ret = i2c_smbus_read_byte_data(client, ADT7411_REG_VDD_LOW);
> +		if (ret < 0)
> +			return ret;
> +		*val = ret * 7000 / 256;
> +		return 0;
> +	case hwmon_in_max:
> +		ret = i2c_smbus_read_byte_data(client, ADT7411_REG_VDD_HIGH);
> +		if (ret < 0)
> +			return ret;
> +		*val = ret * 7000 / 256;
> +		return 0;
> +	case hwmon_in_alarm:
> +		return adt7411_read_in_alarm(dev, 0, val);
>  	default:
>  		return -EOPNOTSUPP;
>  	}
>  }
>
> -static int adt7411_read_in_chan(struct device *dev, u32 attr, int channel,
> -				long *val)
> +static int adt7411_update_vref(struct device *dev)
>  {
>  	struct adt7411_data *data = dev_get_drvdata(dev);
>  	struct i2c_client *client = data->client;
> +	int val;
>
> -	int ret;
> -	int lsb_reg, lsb_shift;
> -	int nr = channel - 1;
> -
> -	mutex_lock(&data->update_lock);
>  	if (time_after_eq(jiffies, data->next_update)) {
> -		ret = i2c_smbus_read_byte_data(client, ADT7411_REG_CFG3);
> -		if (ret < 0)
> -			goto exit_unlock;
> +		val = i2c_smbus_read_byte_data(client, ADT7411_REG_CFG3);
> +		if (val < 0)
> +			return val;
>
> -		if (ret & ADT7411_CFG3_REF_VDD) {
> -			ret = adt7411_read_in_vdd(dev, hwmon_in_input,
> +		if (val & ADT7411_CFG3_REF_VDD) {
> +			val = adt7411_read_in_vdd(dev, hwmon_in_input,
>  						  &data->vref_cached);
> -			if (ret < 0)
> -				goto exit_unlock;
> +			if (val < 0)
> +				return val;
>  		} else {
>  			data->vref_cached = 2250;
>  		}
> @@ -212,6 +284,24 @@ static int adt7411_read_in_chan(struct device *dev, u32 attr, int channel,
>  		data->next_update = jiffies + HZ;
>  	}
>
> +	return 0;
> +}
> +
> +static int adt7411_read_in_chan(struct device *dev, u32 attr, int channel,
> +				long *val)
> +{
> +	struct adt7411_data *data = dev_get_drvdata(dev);
> +	struct i2c_client *client = data->client;
> +
> +	int ret;
> +	int reg, lsb_reg, lsb_shift;
> +	int nr = channel - 1;
> +
> +	mutex_lock(&data->update_lock);
> +	ret = adt7411_update_vref(dev);
> +	if (ret < 0)
> +		goto exit_unlock;
> +
>  	switch (attr) {
>  	case hwmon_in_input:
>  		lsb_reg = ADT7411_REG_EXT_TEMP_AIN14_LSB + (nr >> 2);
> @@ -223,6 +313,20 @@ static int adt7411_read_in_chan(struct device *dev, u32 attr, int channel,
>  		*val = ret * data->vref_cached / 1024;
>  		ret = 0;
>  		break;
> +	case hwmon_in_min:
> +	case hwmon_in_max:
> +		reg = (attr == hwmon_in_min)
> +			? ADT7411_REG_IN_LOW(channel)
> +			: ADT7411_REG_IN_HIGH(channel);
> +		ret = i2c_smbus_read_byte_data(client, reg);
> +		if (ret < 0)
> +			goto exit_unlock;
> +		*val = ret * data->vref_cached / 256;
> +		ret = 0;
> +		break;
> +	case hwmon_in_alarm:
> +		ret = adt7411_read_in_alarm(dev, channel, val);
> +		break;
>  	default:
>  		ret = -EOPNOTSUPP;
>  		break;
> @@ -241,12 +345,44 @@ static int adt7411_read_in(struct device *dev, u32 attr, int channel,
>  		return adt7411_read_in_chan(dev, attr, channel, val);
>  }
>
> +
> +static int adt7411_read_temp_alarm(struct device *dev, u32 attr, int channel,
> +				   long *val)
> +{
> +	struct adt7411_data *data = dev_get_drvdata(dev);
> +	struct i2c_client *client = data->client;
> +	int ret, bit;
> +
> +	ret = i2c_smbus_read_byte_data(client, ADT7411_REG_STAT_1);
> +	if (ret < 0)
> +		return ret;
> +
> +	switch (attr) {
> +	case hwmon_temp_min_alarm:
> +		bit = channel ? ADT7411_STAT_1_EXT_TEMP_LOW
> +			      : ADT7411_STAT_1_INT_TEMP_LOW;
> +		break;
> +	case hwmon_temp_max_alarm:
> +		bit = channel ? ADT7411_STAT_1_EXT_TEMP_HIGH_AIN1
> +			      : ADT7411_STAT_1_INT_TEMP_HIGH;
> +		break;
> +	case hwmon_temp_fault:
> +		bit = ADT7411_STAT_1_EXT_TEMP_FAULT;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	*val = !!(ret & bit);
> +	return 0;
> +}
> +
>  static int adt7411_read_temp(struct device *dev, u32 attr, int channel,
>  			     long *val)
>  {
>  	struct adt7411_data *data = dev_get_drvdata(dev);
>  	struct i2c_client *client = data->client;
> -	int ret, regl, regh;
> +	int ret, reg, regl, regh;
>
>  	switch (attr) {
>  	case hwmon_temp_input:
> @@ -260,6 +396,21 @@ static int adt7411_read_temp(struct device *dev, u32 attr, int channel,
>  		ret = ret & 0x200 ? ret - 0x400 : ret; /* 10 bit signed */
>  		*val = ret * 250;
>  		return 0;
> +	case hwmon_temp_min:
> +	case hwmon_temp_max:
> +		reg = (attr == hwmon_temp_min)
> +			? ADT7411_REG_TEMP_LOW(channel)
> +			: ADT7411_REG_TEMP_HIGH(channel);
> +		ret = i2c_smbus_read_byte_data(client, reg);
> +		if (ret < 0)
> +			return ret;
> +		ret = ret & 0x80 ? ret - 0x100 : ret; /* 8 bit signed */
> +		*val = ret * 1000;
> +		return 0;
> +	case hwmon_temp_min_alarm:
> +	case hwmon_temp_max_alarm:
> +	case hwmon_temp_fault:
> +		return adt7411_read_temp_alarm(dev, attr, channel, val);
>  	default:
>  		return -EOPNOTSUPP;
>  	}
> @@ -278,26 +429,143 @@ static int adt7411_read(struct device *dev, enum hwmon_sensor_types type,
>  	}
>  }
>
> +static int adt7411_write_in_vdd(struct device *dev, u32 attr, long val)
> +{
> +	struct adt7411_data *data = dev_get_drvdata(dev);
> +	struct i2c_client *client = data->client;
> +	int reg;
> +
> +	val = DIV_ROUND_CLOSEST(val * 256, 7000);

Causes overflow. You have to clamp before the DIV_ROUND_CLOSEST().

> +	val = clamp_val(val, 0, 255);
> +
> +	switch (attr) {
> +	case hwmon_in_min:
> +		reg = ADT7411_REG_VDD_LOW;
> +		break;
> +	case hwmon_in_max:
> +		reg = ADT7411_REG_VDD_HIGH;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	return i2c_smbus_write_byte_data(client, reg, val);
> +}
> +
> +static int adt7411_write_in_chan(struct device *dev, u32 attr, int channel,
> +				 long val)
> +{
> +	struct adt7411_data *data = dev_get_drvdata(dev);
> +	struct i2c_client *client = data->client;
> +	int ret, reg;
> +
> +	mutex_lock(&data->update_lock);
> +	ret = adt7411_update_vref(dev);
> +	if (ret < 0)
> +		goto exit_unlock;
> +	val = DIV_ROUND_CLOSEST(val * 256, data->vref_cached);

Same as before.

> +	val = clamp_val(val, 0, 255);
> +
> +	switch (attr) {
> +	case hwmon_in_min:
> +		reg = ADT7411_REG_IN_LOW(channel);
> +		break;
> +	case hwmon_in_max:
> +		reg = ADT7411_REG_IN_HIGH(channel);
> +		break;
> +	default:
> +		ret = -EOPNOTSUPP;
> +		goto exit_unlock;
> +	}
> +
> +	ret = i2c_smbus_write_byte_data(client, reg, val);
> + exit_unlock:
> +	mutex_unlock(&data->update_lock);
> +	return ret;
> +}
> +
> +static int adt7411_write_in(struct device *dev, u32 attr, int channel,
> +			    long val)
> +{
> +	if (channel == 0)
> +		return adt7411_write_in_vdd(dev, attr, val);
> +	else
> +		return adt7411_write_in_chan(dev, attr, channel, val);
> +}
> +
> +static int adt7411_write_temp(struct device *dev, u32 attr, int channel,
> +			      long val)
> +{
> +	struct adt7411_data *data = dev_get_drvdata(dev);
> +	struct i2c_client *client = data->client;
> +	int reg;
> +
> +	val = DIV_ROUND_CLOSEST(val, 1000);

Same as before (DIV_ROUND_CLOSEST() needs to add to val for rounding).
Try writing MAX_LONG (9223372036854775807) and you'll see.

> +	val = clamp_val(val, -128, 127);
> +
> +	switch (attr) {
> +	case hwmon_temp_min:
> +		reg = ADT7411_REG_TEMP_LOW(channel);
> +		break;
> +	case hwmon_temp_max:
> +		reg = ADT7411_REG_TEMP_HIGH(channel);
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	return i2c_smbus_write_byte_data(client, reg, val);
> +}
> +
> +static int adt7411_write(struct device *dev, enum hwmon_sensor_types type,
> +			 u32 attr, int channel, long val)
> +{
> +	switch (type) {
> +	case hwmon_in:
> +		return adt7411_write_in(dev, attr, channel, val);
> +	case hwmon_temp:
> +		return adt7411_write_temp(dev, attr, channel, val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
>  static umode_t adt7411_is_visible(const void *_data,
>  				  enum hwmon_sensor_types type,
>  				  u32 attr, int channel)
>  {
>  	const struct adt7411_data *data = _data;
> +	bool visible;
>
>  	switch (type) {
>  	case hwmon_in:
> -		if (channel > 0 && channel < 3)
> -			return data->use_ext_temp ? 0 : S_IRUGO;
> -		else
> -			return S_IRUGO;
> +		visible = channel == 0 || channel >= 3 || !data->use_ext_temp;
> +		switch (attr) {
> +		case hwmon_in_input:
> +		case hwmon_in_alarm:
> +			return visible ? S_IRUGO : 0;
> +		case hwmon_in_min:
> +		case hwmon_in_max:
> +			return visible ? S_IRUGO | S_IWUSR : 0;
> +		}
> +		break;
>  	case hwmon_temp:
> -		if (channel == 1)
> -			return data->use_ext_temp ? S_IRUGO : 0;
> -		else
> -			return S_IRUGO;
> +		visible = channel == 0 || data->use_ext_temp;
> +		switch (attr) {
> +		case hwmon_temp_input:
> +		case hwmon_temp_min_alarm:
> +		case hwmon_temp_max_alarm:
> +		case hwmon_temp_fault:
> +			return visible ? S_IRUGO : 0;
> +		case hwmon_temp_min:
> +		case hwmon_temp_max:
> +			return visible ? S_IRUGO | S_IWUSR : 0;
> +		}
> +		break;
>  	default:
> -		return 0;
> +		break;
>  	}
> +	return 0;
>  }
>
>  static int adt7411_detect(struct i2c_client *client,
> @@ -371,15 +639,15 @@ static int adt7411_init_device(struct adt7411_data *data)
>  }
>
>  static const u32 adt7411_in_config[] = {
> -	HWMON_I_INPUT,
> -	HWMON_I_INPUT,
> -	HWMON_I_INPUT,
> -	HWMON_I_INPUT,
> -	HWMON_I_INPUT,
> -	HWMON_I_INPUT,
> -	HWMON_I_INPUT,
> -	HWMON_I_INPUT,
> -	HWMON_I_INPUT,
> +	HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX | HWMON_I_ALARM,
> +	HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX | HWMON_I_ALARM,
> +	HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX | HWMON_I_ALARM,
> +	HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX | HWMON_I_ALARM,
> +	HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX | HWMON_I_ALARM,
> +	HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX | HWMON_I_ALARM,
> +	HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX | HWMON_I_ALARM,
> +	HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX | HWMON_I_ALARM,
> +	HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX | HWMON_I_ALARM,
>  	0
>  };
>
> @@ -389,8 +657,10 @@ static const struct hwmon_channel_info adt7411_in = {
>  };
>
>  static const u32 adt7411_temp_config[] = {
> -	HWMON_T_INPUT,
> -	HWMON_T_INPUT,
> +	HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MIN_ALARM |
> +		HWMON_T_MAX | HWMON_T_MAX_ALARM,
> +	HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MIN_ALARM |
> +		HWMON_T_MAX | HWMON_T_MAX_ALARM | HWMON_T_FAULT,
>  	0
>  };
>
> @@ -408,6 +678,7 @@ static const struct hwmon_channel_info *adt7411_info[] = {
>  static const struct hwmon_ops adt7411_hwmon_ops = {
>  	.is_visible = adt7411_is_visible,
>  	.read = adt7411_read,
> +	.write = adt7411_write,
>  };
>
>  static const struct hwmon_chip_info adt7411_chip_info = {
>

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