From be821b78af9de886571e3565515a59f966d66f42 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Sun, 26 Oct 2008 17:04:40 +0100 Subject: hwmon: (adt7473) Fix voltage conversion routines 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 Cc: Paulius Zaleckas Cc: Darrick J. Wong --- drivers/hwmon/adt7473.c | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-) diff --git a/drivers/hwmon/adt7473.c b/drivers/hwmon/adt7473.c index 3a0b63136479..b9a8ea30c99c 100644 --- a/drivers/hwmon/adt7473.c +++ b/drivers/hwmon/adt7473.c @@ -319,35 +319,24 @@ out: } /* - * 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, -- cgit v1.2.1