diff options
| author | Guenter Roeck <linux@roeck-us.net> | 2013-06-27 10:07:19 -0700 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2013-06-28 06:43:55 -0700 |
| commit | a50d9a4d9ad3c71341788099d733e4151b8a511b (patch) | |
| tree | b443b672ccc6a1bb6fc50dfdff3f5c5d3cf087ae /drivers/hwmon/ds1621.c | |
| parent | 41fa9a944fce1d7efd5ee3d50ac85b92f42dcc3d (diff) | |
| download | linux-a50d9a4d9ad3c71341788099d733e4151b8a511b.tar.bz2 | |
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: Jean Delvare <khali@linux-fr.org>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon/ds1621.c')
| -rw-r--r-- | drivers/hwmon/ds1621.c | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/drivers/hwmon/ds1621.c b/drivers/hwmon/ds1621.c index 591758bb629f..a26ba7a17c2b 100644 --- a/drivers/hwmon/ds1621.c +++ b/drivers/hwmon/ds1621.c @@ -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); |