charger/rt946x: Add display bias API mt6370_db_set_voltages.

Add mt6370_db_set_voltages to control VBST, VPOS, and VNEG.

TEST=Test with CL:1632132 on krane:
     i2cxfer r 0 0x68 0xb1; see output 0x36
     i2cxfer r 0 0x68 0xb2; see output 0x68
     i2cxfer r 0 0x68 0xb3; see output 0x64
     i2cxfer r 0 0x68 0xb4; see output 0x64
BUG=b:125644770
BRANCH=None

Change-Id: Ia66ba91a2af3a651a71195dd8a2d531bf1ba06e9
Signed-off-by: Yilun Lin <yllin@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1613257
Commit-Ready: Yilun Lin <yllin@chromium.org>
Tested-by: Yilun Lin <yllin@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

2 files changed, 84 insertions, 4 deletions

diff --git a/driver/charger/rt946x.c b/driver/charger/rt946x.c
index 226b4b4d0a..d3d9309129 100644
--- a/driver/charger/rt946x.c
+++ b/driver/charger/rt946x.c
@@ -1059,6 +1059,37 @@ int mt6370_db_external_control(int en)
 				  en << MT6370_SHIFT_DB_EXT_EN);
 }
 
+int mt6370_db_set_voltages(int vbst, int vpos, int vneg)
+{
+	int rv;
+
+	/* set display bias VBST */
+	rv = rt946x_update_bits(MT6370_REG_DBVBST, MT6370_MASK_DB_VBST,
+				rt946x_closest_reg(MT6370_DB_VBST_MIN,
+						   MT6370_DB_VBST_MAX,
+						   MT6370_DB_VBST_STEP, vbst));
+
+	/* set display bias VPOS */
+	rv |= rt946x_update_bits(MT6370_REG_DBVPOS, MT6370_MASK_DB_VPOS,
+				 rt946x_closest_reg(MT6370_DB_VPOS_MIN,
+						    MT6370_DB_VPOS_MAX,
+						    MT6370_DB_VPOS_STEP, vpos));
+
+	/* set display bias VNEG */
+	rv |= rt946x_update_bits(MT6370_REG_DBVNEG, MT6370_MASK_DB_VNEG,
+				 rt946x_closest_reg(MT6370_DB_VNEG_MIN,
+						    MT6370_DB_VNEG_MAX,
+						    MT6370_DB_VNEG_STEP, vneg));
+
+	/* Enable VNEG/VPOS discharge when VNEG/VPOS rails disabled. */
+	rv |= rt946x_update_bits(
+		MT6370_REG_DBCTRL2,
+		MT6370_MASK_DB_VNEG_DISC | MT6370_MASK_DB_VPOS_DISC,
+		MT6370_MASK_DB_VNEG_DISC | MT6370_MASK_DB_VPOS_DISC);
+
+	return rv;
+}
+
 /* MT6370 RGB LED */
 
 int mt6370_led_set_dim_mode(enum mt6370_led_index index,
diff --git a/driver/charger/rt946x.h b/driver/charger/rt946x.h
index aad6d74032..2b8c50ce19 100644
--- a/driver/charger/rt946x.h
+++ b/driver/charger/rt946x.h
@@ -135,14 +135,20 @@
 #define MT6370_REG_RGBCHRINDDIM		0x92
 #define MT6370_REG_RGBCHRINDCTRL	0x93
 
-/* Display bias */
-#define MT6370_REG_DBCTRL1		0XB0
-
-#define RT946X_REG_DPDMIRQ		0xC6
 /* backlight */
 #define MT6370_BACKLIGHT_BLEN		0xA0
 #define MT6370_BACKLIGHT_BLPWM		0xA2
 #define MT6370_BACKLIGHT_BLDIM		0xA5
+
+/* Display bias */
+#define MT6370_REG_DBCTRL1		0XB0
+#define MT6370_REG_DBCTRL2		0XB1
+#define MT6370_REG_DBVBST		0XB2
+#define MT6370_REG_DBVPOS		0XB3
+#define MT6370_REG_DBVNEG		0XB4
+
+#define RT946X_REG_DPDMIRQ		0xC6
+
 /* status event */
 #define MT6370_REG_CHGSTAT1		0xD0
 #define RT946X_REG_CHGSTATC		MT6370_REG_CHGSTAT1
@@ -493,6 +499,37 @@
 #define MT6370_MASK_DB_FREQ_PM		1
 #define MT6370_MASK_DB_PERIODIC_MODE	1
 
+/* ========== DBCTRL1 (mt6370) ============ */
+#define MT6370_MASK_DB_VNEG_DISC	BIT(2)
+#define MT6370_MASK_DB_VPOS_DISC	BIT(5)
+
+/* ========== DBVBST (mt6370) ============ */
+#define MT6370_SHIFT_DB_VBST		0
+
+#define MT6370_MASK_DB_VBST		0x3f
+
+#define MT6370_DB_VBST_MAX		6200
+#define MT6370_DB_VBST_MIN		4000
+#define MT6370_DB_VBST_STEP		50
+
+/* ========== DBVPOS (mt6370) ============ */
+#define MT6370_SHIFT_DB_VPOS		0
+
+#define MT6370_MASK_DB_VPOS		0x3f
+
+#define MT6370_DB_VPOS_MAX		6000
+#define MT6370_DB_VPOS_MIN		4000
+#define MT6370_DB_VPOS_STEP		50
+
+/* ========== DBVNEG (mt6370) ============ */
+#define MT6370_SHIFT_DB_VNEG		0
+
+#define MT6370_MASK_DB_VNEG		0x3f
+
+#define MT6370_DB_VNEG_MAX		6000
+#define MT6370_DB_VNEG_MIN		4000
+#define MT6370_DB_VNEG_STEP		50
+
 /* ========== BLEN 0xA0 (mt6370) ============ */
 #define MT6370_SHIFT_BLED_EXT_EN	7
 #define MT6370_SHIFT_BLED_EN		6
@@ -623,6 +660,18 @@ enum mt6370_led_pwm_freq {
 /* Enable display bias external pin control. */
 int mt6370_db_external_control(int en);
 
+/**
+ * MT6370 display bias voltage settings.
+ *
+ * Set disaply bias voltages for the panel.
+ *
+ * vbst: VBST config in mv.
+ * vpos: VPOS config in mv.
+ * vneg: VNEG config in mv.
+ * return: EC_SUCCESS on succes, and EC_ERROR_* otherwise.
+ */
+int mt6370_db_set_voltages(int vbst, int vpos, int vneg);
+
 /* Set LED brightness */
 int mt6370_led_set_brightness(enum mt6370_led_index index, uint8_t brightness);