media: camss: csid: allow csid to work without a regulator

At least for titan HW, CSID don't have an associated regulator. This change
is necessary to be able to model this in the CSID resources.
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Tested-by: Julian Grahsl <jgrahsl@snap.com>
Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/platform/qcom/camss/camss-csid.c

@@ -160,7 +160,7 @@ static int csid_set_power(struct v4l2_subdev *sd, int on)
 		if (ret < 0)
 			return ret;
 
-		ret = regulator_enable(csid->vdda);
+		ret = csid->vdda ? regulator_enable(csid->vdda) : 0;
 		if (ret < 0) {
 			pm_runtime_put_sync(dev);
 			return ret;
@@ -168,14 +168,16 @@ static int csid_set_power(struct v4l2_subdev *sd, int on)
 
 		ret = csid_set_clock_rates(csid);
 		if (ret < 0) {
-			regulator_disable(csid->vdda);
+			if (csid->vdda)
+				regulator_disable(csid->vdda);
 			pm_runtime_put_sync(dev);
 			return ret;
 		}
 
 		ret = camss_enable_clocks(csid->nclocks, csid->clock, dev);
 		if (ret < 0) {
-			regulator_disable(csid->vdda);
+			if (csid->vdda)
+				regulator_disable(csid->vdda);
 			pm_runtime_put_sync(dev);
 			return ret;
 		}
@@ -186,7 +188,8 @@ static int csid_set_power(struct v4l2_subdev *sd, int on)
 		if (ret < 0) {
 			disable_irq(csid->irq);
 			camss_disable_clocks(csid->nclocks, csid->clock);
-			regulator_disable(csid->vdda);
+			if (csid->vdda)
+				regulator_disable(csid->vdda);
 			pm_runtime_put_sync(dev);
 			return ret;
 		}
@@ -195,7 +198,7 @@ static int csid_set_power(struct v4l2_subdev *sd, int on)
 	} else {
 		disable_irq(csid->irq);
 		camss_disable_clocks(csid->nclocks, csid->clock);
-		ret = regulator_disable(csid->vdda);
+		ret = csid->vdda ? regulator_disable(csid->vdda) : 0;
 		pm_runtime_put_sync(dev);
 	}
 
@@ -631,7 +634,9 @@ int msm_csid_subdev_init(struct camss *camss, struct csid_device *csid,
 
 	/* Regulator */
 
-	csid->vdda = devm_regulator_get(dev, res->regulator[0]);
+	csid->vdda = NULL;
+	if (res->regulator[0])
+		csid->vdda = devm_regulator_get(dev, res->regulator[0]);
 	if (IS_ERR(csid->vdda)) {
 		dev_err(dev, "could not get regulator\n");
 		return PTR_ERR(csid->vdda);