disp: msm: config AB/IBB power when AOD mode enter/exit

ELVDD/ELVSS has a dip during AMODE panel AOD exit hand-off.
According to PMIC team's suggestion, need to config the AB/IBB power
to REGULATOR_MODE_IDLE/REGULATOR_MODE_NORMAL to fix dips.

Change-Id: Ia5cbd4d698de262e02a660f670865c03dda1e04a
Signed-off-by: Wenjun Zhang <wjzhan@codeaurora.org>
Signed-off-by: Yuan Zhao <yzhao@codeaurora.org>

msm/dsi/dsi_pwr.c

@@ -378,3 +378,51 @@ int dsi_pwr_enable_regulator(struct dsi_regulator_info *regs, bool enable)
 
 	return rc;
 }
+
+/*
+ * dsi_pwr_panel_regulator_mode_set()
+ * set the AB/IBB regulator mode for OLED panel
+ * AOD mode entry and exit
+ * @regs:	Pointer to set of regulators to enable or disable.
+ * @reg_name:	Name of panel power we want to set.
+ * @retulator_mode:	Regulator mode values, like:
+ *	REGULATOR_MODE_INVALID
+ *	REGULATOR_MODE_FAST
+ *	REGULATOR_MODE_NORMAL
+ *	REGULATOR_MODE_IDLE
+ *	REGULATOR_MODE_STANDBY
+ *
+ * return: error code in case of failure or 0 for success.
+ */
+int dsi_pwr_panel_regulator_mode_set(struct dsi_regulator_info *regs,
+						const char *reg_name,
+						int regulator_mode)
+{
+	int i = 0, rc = 0;
+	struct dsi_vreg *vreg;
+
+	if (regs->count == 0)
+		return -EINVAL;
+
+	if (!regs->vregs)
+		return -EINVAL;
+
+	for (i = 0; i < regs->count; i++) {
+		vreg = &regs->vregs[i];
+		if (!strcmp(vreg->vreg_name, reg_name)) {
+			rc = regulator_set_mode(vreg->vreg,
+							regulator_mode);
+			if (rc)
+				DSI_ERR("Regulator %s set mode %d failed\n",
+					vreg->vreg_name, rc);
+			break;
+		}
+	}
+
+	if (i >= regs->count) {
+		DSI_ERR("Regulator %s was not found\n", reg_name);
+		return -EINVAL;
+	}
+
+	return rc;
+}