From: Bin Yang <bin.yang@intel.com>
Date: Thu, 6 Oct 2011 15:18:35 +0000 (+0100)
Subject: gpadc: fix battery temp accuracy
X-Git-Tag: 2.1b_release~1945
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=88a1c8af94eada344b3b525e8a9ee0ccd642d5dd;p=kernel%2Fkernel-mfld-blackbay.git

gpadc: fix battery temp accuracy

From oscilloscope result, BPTHERM takes <1ms to stabilize.
So it needs to add 1ms delay after VBUSREF is enabled.

Change-Id: I34503b94bd9eec73432bfe817bceed18a104edcc
Signed-off-by: Bin Yang <bin.yang@intel.com>
---

diff --git a/drivers/hwmon/intel_mid_gpadc.c b/drivers/hwmon/intel_mid_gpadc.c
index acaeef2..b61e5dd 100644
--- a/drivers/hwmon/intel_mid_gpadc.c
+++ b/drivers/hwmon/intel_mid_gpadc.c
@@ -82,6 +82,8 @@
 
 #define PM_QOS_ADC_DRV_VALUE	4999
 
+#define GPADC_POWERON_DELAY	1
+
 struct gpadc_info {
 	int initialized;
 
@@ -150,9 +152,12 @@ static int gpadc_poweron(struct gpadc_info *mgi, int vref)
 {
 	if (gpadc_set_bits(ADC1CNTL1, ADC1CNTL1_ADEN) != 0)
 		return -EIO;
-	if (vref)
+	msleep(GPADC_POWERON_DELAY);
+	if (vref) {
 		if (gpadc_set_bits(ADC1CNTL3, ADC1CNTL3_ADCTHERM) != 0)
 			return -EIO;
+		msleep(GPADC_POWERON_DELAY);
+	}
 	return 0;
 }