soc/mediatek: Add support for regulator VIO18

To provide power to MIPI panel STA_HIMAX83102_J02, add support for
regulator VIO18.

BUG=b:272425116
TEST=test firmware display pass for STA_HIMAX83102_J02 on Starmie.

Change-Id: I3c3aa105e648b87fc39f881d762002f67b4422b5
Signed-off-by: Cong Yang <yangcong5@huaqin.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74341
Reviewed-by: Yidi Lin <yidilin@google.com>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Ruihai Zhou <zhouruihai@huaqin.corp-partner.google.com>

src/soc/mediatek/common/include/soc/regulator.h

@@ -23,6 +23,7 @@ enum mtk_regulator {
 	MTK_REGULATOR_VRF12,
 	MTK_REGULATOR_VCN33,
 	MTK_REGULATOR_VDD18,
+	MTK_REGULATOR_VIO18,
 	MTK_REGULATOR_NUM,
 };
 

src/soc/mediatek/mt8186/include/soc/mt6366.h

@@ -39,6 +39,7 @@ enum {
 	PMIC_VDRAM1_DBG0		= 0x161e,
 	PMIC_VDRAM1_VOSEL		= 0x1626,
 	PMIC_SMPS_ANA_CON0		= 0x1808,
+	PMIC_LDO_VIO18_CON0		= 0x1aec,
 	PMIC_VDDQ_OP_EN			= 0x1b16,
 	PMIC_VSRAM_PROC12_OP_EN		= 0x1b90,
 	PMIC_VSRAM_PROC12_DBG0		= 0x1ba2,
@@ -67,6 +68,7 @@ enum mt6366_regulator_id {
 	MT6366_VSRAM_PROC12,
 	MT6366_VRF12,
 	MT6366_VCN33,
+	MT6366_VIO18,
 	MT6366_REGULATOR_NUM,
 };
 

src/soc/mediatek/mt8186/mt6366.c

@@ -787,6 +787,19 @@ static void pmic_set_vcn33_vol(u32 vcn33_uv)
 	pwrap_write_field(PMIC_LDO_VCN33_CON0_0, 1, 0x1, 0);
 }
 
+#define VIO18_VOLTAGE_UV 1800000
+
+static u32 pmic_get_vio18_vol(void)
+{
+	return pwrap_read_field(PMIC_LDO_VIO18_CON0, 0x1, 0) ? VIO18_VOLTAGE_UV : 0;
+}
+
+static void pmic_set_vio18_vol(u32 vio18_uv)
+{
+	assert(vio18_uv == VIO18_VOLTAGE_UV);
+	pwrap_write_field(PMIC_LDO_VIO18_CON0, 1, 0x1, 0);
+}
+
 static void pmic_wdt_set(void)
 {
 	/* [5]=1, RG_WDTRSTB_DEB */
@@ -914,6 +927,9 @@ void mt6366_set_voltage(enum mt6366_regulator_id id, u32 voltage_uv)
 	case MT6366_VCN33:
 		pmic_set_vcn33_vol(voltage_uv);
 		break;
+	case MT6366_VIO18:
+		pmic_set_vio18_vol(voltage_uv);
+		break;
 	default:
 		printk(BIOS_ERR, "%s: PMIC %d is not supported\n", __func__, id);
 		break;
@@ -941,6 +957,8 @@ u32 mt6366_get_voltage(enum mt6366_regulator_id id)
 		return pmic_get_vrf12_vol();
 	case MT6366_VCN33:
 		return pmic_get_vcn33_vol();
+	case MT6366_VIO18:
+		return pmic_get_vio18_vol();
 	default:
 		printk(BIOS_ERR, "%s: PMIC %d is not supported\n", __func__, id);
 		break;