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hwmon: (adt7473) Fix voltage conversion routines

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Fix voltage conversion routines. Based on an earlier patch from
Paulius Zaleckas.

According to the datasheet voltage is scaled with resistors and
value 192 is nominal voltage. 0 is 0V.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
Cc: Darrick J. Wong <djwong@us.ibm.com>
This commit is contained in:
Jean Delvare 2008-10-26 17:04:40 +01:00
parent 97ae60bb38
commit be821b78af
1 changed files with 9 additions and 20 deletions
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29
drivers/hwmon/adt7473.c
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@ -319,35 +319,24 @@ static struct adt7473_data *adt7473_update_device(struct device *dev)
}
/*
* On this chip, voltages are given as a count of steps between a minimum
* and maximum voltage, not a direct voltage.
* Conversions
*/
static const int volt_convert_table[][2] = {
{2997, 3},
{4395, 4},
/* IN are scaled acording to built-in resistors */
static const int adt7473_scaling[] = { /* .001 Volts */
2250, 3300
};
#define SCALE(val, from, to) (((val) * (to) + ((from) / 2)) / (from))
static int decode_volt(int volt_index, u8 raw)
{
int cmax = volt_convert_table[volt_index][0];
int cmin = volt_convert_table[volt_index][1];
return ((raw * (cmax - cmin)) / 255) + cmin;
return SCALE(raw, 192, adt7473_scaling[volt_index]);
}
static u8 encode_volt(int volt_index, int cooked)
{
int cmax = volt_convert_table[volt_index][0];
int cmin = volt_convert_table[volt_index][1];
u8 x;
if (cooked > cmax)
cooked = cmax;
else if (cooked < cmin)
cooked = cmin;
x = ((cooked - cmin) * 255) / (cmax - cmin);
return x;
int raw = SCALE(cooked, adt7473_scaling[volt_index], 192);
return SENSORS_LIMIT(raw, 0, 255);
}
static ssize_t show_volt_min(struct device *dev,