thermal: rockchip: rk3399: enhance the tsadc's bandgap feature

Due to the voltage ripple, the sensing data of the tsadc is not accurate.
And in this patch, the bandgap feature is enhanced to remove the voltage
ripple, and then the tsadc can sense the temperature more precisely.

Obsolete codes are removed as well.

Change-Id: Ifdd98def63212bc13306e7d5befee5eb32dbbc2f
Signed-off-by: Rocky Hao <rocky.hao@rock-chips.com>

diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
index f46ab8721bc22920a07b0d19dc1453a328c42666..43f3371360b2905d5947379ed7d03f7d761207c3 100644 (file)
--- a/drivers/thermal/rockchip_thermal.c
+++ b/drivers/thermal/rockchip_thermal.c
@@ -222,10 +222,10 @@ struct rockchip_thermal_data {
 #define GRF_TSADC_TESTBIT_L                    0x0e648
 #define GRF_TSADC_TESTBIT_H                    0x0e64c
 
-#define GRF_TSADC_TSEN_PD_ON                   (0x30003 << 0)
-#define GRF_TSADC_TSEN_PD_OFF                  (0x30000 << 0)
 #define GRF_SARADC_TESTBIT_ON                  (0x10001 << 2)
 #define GRF_TSADC_TESTBIT_H_ON                 (0x10001 << 2)
+#define GRF_TSADC_VCM_EN_L                     (0x10001 << 7)
+#define GRF_TSADC_VCM_EN_H                     (0x10001 << 7)
 
 /**
  * struct tsadc_table - code to temperature conversion table
@@ -567,9 +567,10 @@ static void rk_tsadcv3_initialize(struct regmap *grf, void __iomem *regs,
                               regs + TSADCV2_HIGHT_TSHUT_DEBOUNCE);
 
        } else {
-               regmap_write(grf, GRF_TSADC_TESTBIT_L, GRF_TSADC_TSEN_PD_ON);
-               mdelay(10);
-               regmap_write(grf, GRF_TSADC_TESTBIT_L, GRF_TSADC_TSEN_PD_OFF);
+               /* Enable the voltage common mode feature */
+               regmap_write(grf, GRF_TSADC_TESTBIT_L, GRF_TSADC_VCM_EN_L);
+               regmap_write(grf, GRF_TSADC_TESTBIT_H, GRF_TSADC_VCM_EN_H);
+
                udelay(100); /* The spec note says at least 15 us */
                regmap_write(grf, GRF_SARADC_TESTBIT, GRF_SARADC_TESTBIT_ON);
                regmap_write(grf, GRF_TSADC_TESTBIT_H, GRF_TSADC_TESTBIT_H_ON);