From 9c9cf9e26363d0c06d0e01d5304477be97ace5cb Mon Sep 17 00:00:00 2001 From: Philip Rakity Date: Fri, 25 Nov 2011 21:25:23 +0400 Subject: [PATCH] max8925_power: Fix incorrect voltage and current calculation The datasheet indicates a 12 bit value is returned for i2c registers for voltage and current. Code was assuming 8 bits. But default for chip is 12 bit return value. Voltage is returned in 2mV units -- adjust to return as uV per linux power spec Adjust current calculation to return units in uA. Signed-off-by: Philip Rakity Signed-off-by: Anton Vorontsov --- drivers/power/max8925_power.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/power/max8925_power.c b/drivers/power/max8925_power.c index a70e16d3a3dc..b16bd71f24fb 100644 --- a/drivers/power/max8925_power.c +++ b/drivers/power/max8925_power.c @@ -188,7 +188,7 @@ static int start_measure(struct max8925_power_info *info, int type) } max8925_bulk_read(info->adc, meas_reg, 2, buf); - ret = (buf[0] << 4) | (buf[1] >> 4); + ret = ((buf[0]<<8) | buf[1]) >> 4; return ret; } @@ -208,7 +208,7 @@ static int max8925_ac_get_prop(struct power_supply *psy, if (info->ac_online) { ret = start_measure(info, MEASURE_VCHG); if (ret >= 0) { - val->intval = ret << 1; /* unit is mV */ + val->intval = ret * 2000; /* unit is uV */ goto out; } } @@ -242,7 +242,7 @@ static int max8925_usb_get_prop(struct power_supply *psy, if (info->usb_online) { ret = start_measure(info, MEASURE_VCHG); if (ret >= 0) { - val->intval = ret << 1; /* unit is mV */ + val->intval = ret * 2000; /* unit is uV */ goto out; } } @@ -266,7 +266,6 @@ static int max8925_bat_get_prop(struct power_supply *psy, union power_supply_propval *val) { struct max8925_power_info *info = dev_get_drvdata(psy->dev->parent); - long long int tmp = 0; int ret = 0; switch (psp) { @@ -277,7 +276,7 @@ static int max8925_bat_get_prop(struct power_supply *psy, if (info->bat_online) { ret = start_measure(info, MEASURE_VMBATT); if (ret >= 0) { - val->intval = ret << 1; /* unit is mV */ + val->intval = ret * 2000; /* unit is uV */ ret = 0; break; } @@ -288,8 +287,8 @@ static int max8925_bat_get_prop(struct power_supply *psy, if (info->bat_online) { ret = start_measure(info, MEASURE_ISNS); if (ret >= 0) { - tmp = (long long int)ret * 6250 / 4096 - 3125; - ret = (int)tmp; + /* assume r_sns is 0.02 */ + ret = ((ret * 6250) - 3125) /* uA */; val->intval = 0; if (ret > 0) val->intval = ret; /* unit is mA */ -- 2.34.1