disp: msm: disable regulator load after the regulator was disabled

Setting a lower load can make the regulator enter into LPM. Now the
lower load was set before the regulator disable, there's a risk here.
The regulator has been LPM, while it was not disable, if the cosumer
has a higher current needed than LPM at this time, that will lead OCP
on this regulator. The right operation for a regulator enable/disable
should be:
 1. regulator_set_voltage(vreg, active_min_uV, active_max_uV) and
    regulator_set_load(vreg, active_load_uA); in either order
 2. regulator_enable()
 3. regulator_disable()
 4. regulator_set_voltage(vreg, inactive_min_uV, inactive_max_uV)
    and regulator_set_load(vreg, inactive_load_uA); in either order

Change-Id: Ibe4f888a5675baf2691e479daa163d8867902e69
Signed-off-by: Zhao, Yuan <yzhao@codeaurora.org>

msm/sde_io_util.c

@@ -419,15 +419,15 @@ int msm_dss_enable_vreg(struct dss_vreg *in_vreg, int num_vreg, int enable)
 			if (in_vreg[i].pre_off_sleep)
 				usleep_range(in_vreg[i].pre_off_sleep * 1000,
 					(in_vreg[i].pre_off_sleep * 1000) + 10);
-			regulator_set_load(in_vreg[i].vreg,
-				in_vreg[i].disable_load);
 			regulator_disable(in_vreg[i].vreg);
-			if (regulator_count_voltages(in_vreg[i].vreg) > 0)
-				regulator_set_voltage(in_vreg[i].vreg, 0,
-						in_vreg[i].max_voltage);
 			if (in_vreg[i].post_off_sleep)
 				usleep_range(in_vreg[i].post_off_sleep * 1000,
 				(in_vreg[i].post_off_sleep * 1000) + 10);
+			regulator_set_load(in_vreg[i].vreg,
+				in_vreg[i].disable_load);
+			if (regulator_count_voltages(in_vreg[i].vreg) > 0)
+				regulator_set_voltage(in_vreg[i].vreg, 0,
+						in_vreg[i].max_voltage);
 		}
 	}
 	return rc;
@@ -440,12 +440,12 @@ vreg_set_opt_mode_fail:
 		if (in_vreg[i].pre_off_sleep)
 			usleep_range(in_vreg[i].pre_off_sleep * 1000,
 				(in_vreg[i].pre_off_sleep * 1000) + 10);
-		regulator_set_load(in_vreg[i].vreg,
-			in_vreg[i].disable_load);
 		regulator_disable(in_vreg[i].vreg);
 		if (in_vreg[i].post_off_sleep)
 			usleep_range(in_vreg[i].post_off_sleep * 1000,
 				(in_vreg[i].post_off_sleep * 1000) + 10);
+		regulator_set_load(in_vreg[i].vreg,
+			in_vreg[i].disable_load);
 	}
 
 	return rc;