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Commit a50d9a4d authored by Guenter Roeck's avatar Guenter Roeck
Browse files

hwmon: (ds1621) Fix temperature rounding operations 



Commit "hwmon: (ds1621) Add ds1721 chip support" broke rounding
for chips or configurations with less than 12 bit resolution.

Tested-by: default avatarJean Delvare <khali@linux-fr.org>
Acked-by: default avatarJean Delvare <khali@linux-fr.org>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 41fa9a94

drivers/hwmon/ds1621.c

+12 −9
Original line number Diff line number Diff line
@@ -128,6 +128,8 @@ struct ds1621_data { 


	u16 temp[3];			/* Register values, word */

	u8 conf;			/* Register encoding, combined */

	u8 zbits;			/* Resolution encoded as number of

					 * zero bits */

	u16 update_interval;		/* Conversion rate in milliseconds */

};
@@ -139,16 +141,14 @@ static inline int DS1621_TEMP_FROM_REG(u16 reg) 
/*

 * TEMP: 0.001C/bit (-55C to +125C)

 * REG:

 *  - 1621, 1625: 0.5C/bit

 *  - 1631, 1721, 1731: 0.0625C/bit

 * Assume highest resolution and let the bits fall where they may..

 *  - 1621, 1625: 0.5C/bit, 7 zero-bits

 *  - 1631, 1721, 1731: 0.0625C/bit, 4 zero-bits

 */

static inline u16 DS1621_TEMP_TO_REG(long temp)

static inline u16 DS1621_TEMP_TO_REG(long temp, u8 zbits)

{

	int ntemp = clamp_val(temp, DS1621_TEMP_MIN, DS1621_TEMP_MAX);

	ntemp += (ntemp < 0 ? -31 : 31);

	ntemp = DIV_ROUND_CLOSEST(ntemp * 10, 625) << 4;

	return (u16)ntemp;

	temp = clamp_val(temp, DS1621_TEMP_MIN, DS1621_TEMP_MAX);

	temp = DIV_ROUND_CLOSEST(temp * (1 << (8 - zbits)), 1000) << zbits;

	return temp;

}



static void ds1621_init_client(struct i2c_client *client)
@@ -172,6 +172,7 @@ static void ds1621_init_client(struct i2c_client *client) 
	switch (data->kind) {

	case ds1625:

		data->update_interval = DS1625_CONVERSION_MAX;

		data->zbits = 7;

		sreg = DS1621_COM_START;

		break;

	case ds1631:
@@ -180,10 +181,12 @@ static void ds1621_init_client(struct i2c_client *client) 
		resol = (new_conf & DS1621_REG_CONFIG_RESOL) >>

			 DS1621_REG_CONFIG_RESOL_SHIFT;

		data->update_interval = ds1721_convrates[resol];

		data->zbits = 7 - resol;

		sreg = DS1721_COM_START;

		break;

	default:

		data->update_interval = DS1621_CONVERSION_MAX;

		data->zbits = 7;

		sreg = DS1621_COM_START;

		break;

	}
@@ -254,7 +257,7 @@ static ssize_t set_temp(struct device *dev, struct device_attribute *da, 
		return err;



	mutex_lock(&data->update_lock);

	data->temp[attr->index] = DS1621_TEMP_TO_REG(val);

	data->temp[attr->index] = DS1621_TEMP_TO_REG(val, data->zbits);

	i2c_smbus_write_word_swapped(client, DS1621_REG_TEMP[attr->index],

				     data->temp[attr->index]);

	mutex_unlock(&data->update_lock);