power: supply: cpcap-battery: Fix signed counter sample register

The accumulator sample register is signed 32-bits wide register on
droid 4. And only the earlier version of cpcap has a signed 24-bits
wide register. We're currently passing it around as unsigned, so
let's fix that and use sign_extend32() for the earlier revision.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/cpcap-battery.c

@@ -82,7 +82,7 @@ struct cpcap_battery_config {
 };
 
 struct cpcap_coulomb_counter_data {
-	s32 sample;		/* 24-bits */
+	s32 sample;		/* 24 or 32 bits */
 	s32 accumulator;
 	s16 offset;		/* 10-bits */
 };
@@ -213,7 +213,7 @@ static int cpcap_battery_get_current(struct cpcap_battery_ddata *ddata)
  * TI or ST coulomb counter in the PMIC.
  */
 static int cpcap_battery_cc_raw_div(struct cpcap_battery_ddata *ddata,
-				    u32 sample, s32 accumulator,
+				    s32 sample, s32 accumulator,
 				    s16 offset, u32 divider)
 {
 	s64 acc;
@@ -224,7 +224,6 @@ static int cpcap_battery_cc_raw_div(struct cpcap_battery_ddata *ddata,
 	if (!divider)
 		return 0;
 
-	sample &= 0xffffff;		/* 24-bits, unsigned */
 	offset &= 0x7ff;		/* 10-bits, signed */
 
 	switch (ddata->vendor) {
@@ -259,7 +258,7 @@ static int cpcap_battery_cc_raw_div(struct cpcap_battery_ddata *ddata,
 
 /* 3600000μAms = 1μAh */
 static int cpcap_battery_cc_to_uah(struct cpcap_battery_ddata *ddata,
-				   u32 sample, s32 accumulator,
+				   s32 sample, s32 accumulator,
 				   s16 offset)
 {
 	return cpcap_battery_cc_raw_div(ddata, sample,
@@ -268,7 +267,7 @@ static int cpcap_battery_cc_to_uah(struct cpcap_battery_ddata *ddata,
 }
 
 static int cpcap_battery_cc_to_ua(struct cpcap_battery_ddata *ddata,
-				  u32 sample, s32 accumulator,
+				  s32 sample, s32 accumulator,
 				  s16 offset)
 {
 	return cpcap_battery_cc_raw_div(ddata, sample,
@@ -312,6 +311,8 @@ cpcap_battery_read_accumulated(struct cpcap_battery_ddata *ddata,
 	/* Sample value CPCAP_REG_CCS1 & 2 */
 	ccd->sample = (buf[1] & 0x0fff) << 16;
 	ccd->sample |= buf[0];
+	if (ddata->vendor == CPCAP_VENDOR_TI)
+		ccd->sample = sign_extend32(24, ccd->sample);
 
 	/* Accumulator value CPCAP_REG_CCA1 & 2 */
 	ccd->accumulator = ((s16)buf[3]) << 16;