linux-kernel - [PATCH v1 1/4] media: cadence: csi2rx: Support runtime PM

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Message-Id: <20240326031237.25331-2-changhuang.liang@starfivetech.com>
Date: Mon, 25 Mar 2024 20:12:34 -0700
From: Changhuang Liang <changhuang.liang@...rfivetech.com>
To: Mauro Carvalho Chehab <mchehab@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Hans Verkuil <hverkuil-cisco@...all.nl>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Jack Zhu <jack.zhu@...rfivetech.com>,
	Changhuang Liang <changhuang.liang@...rfivetech.com>,
	Dan Carpenter <dan.carpenter@...aro.org>,
	Jayshri Pawar <jpawar@...ence.com>,
	Jai Luthra <j-luthra@...com>,
	linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-staging@...ts.linux.dev
Subject: [PATCH v1 1/4] media: cadence: csi2rx: Support runtime PM

From: Jayshri Pawar <jpawar@...ence.com>

Use runtime power management hooks to save power when CSI-RX is not in
use. Also stop/start any in-progress streams, which might happen during
a system suspend/resume cycle.

Signed-off-by: Jayshri Pawar <jpawar@...ence.com>
Co-developed-by: Jai Luthra <j-luthra@...com>
Signed-off-by: Jai Luthra <j-luthra@...com>
Signed-off-by: Changhuang Liang <changhuang.liang@...rfivetech.com>
---
 drivers/media/platform/cadence/cdns-csi2rx.c | 43 +++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
index 2d7b0508cc9a..a8b86369e34f 100644
--- a/drivers/media/platform/cadence/cdns-csi2rx.c
+++ b/drivers/media/platform/cadence/cdns-csi2rx.c
@@ -364,6 +364,12 @@ static int csi2rx_s_stream(struct v4l2_subdev *subdev, int enable)
 	struct csi2rx_priv *csi2rx = v4l2_subdev_to_csi2rx(subdev);
 	int ret = 0;
 
+	if (enable) {
+		ret = pm_runtime_resume_and_get(csi2rx->dev);
+		if (ret < 0)
+			return ret;
+	}
+
 	mutex_lock(&csi2rx->lock);
 
 	if (enable) {
@@ -373,8 +379,10 @@ static int csi2rx_s_stream(struct v4l2_subdev *subdev, int enable)
 		 */
 		if (!csi2rx->count) {
 			ret = csi2rx_start(csi2rx);
-			if (ret)
+			if (ret) {
+				pm_runtime_put(csi2rx->dev);
 				goto out;
+			}
 		}
 
 		csi2rx->count++;
@@ -386,6 +394,8 @@ static int csi2rx_s_stream(struct v4l2_subdev *subdev, int enable)
 		 */
 		if (!csi2rx->count)
 			csi2rx_stop(csi2rx);
+
+		pm_runtime_put(csi2rx->dev);
 	}
 
 out:
@@ -659,6 +669,29 @@ static int csi2rx_parse_dt(struct csi2rx_priv *csi2rx)
 	return ret;
 }
 
+static int csi2rx_suspend(struct device *dev)
+{
+	struct csi2rx_priv *csi2rx = dev_get_drvdata(dev);
+
+	mutex_lock(&csi2rx->lock);
+	if (csi2rx->count)
+		csi2rx_stop(csi2rx);
+	mutex_unlock(&csi2rx->lock);
+
+	return 0;
+}
+
+static int csi2rx_resume(struct device *dev)
+{
+	struct csi2rx_priv *csi2rx = dev_get_drvdata(dev);
+
+	mutex_lock(&csi2rx->lock);
+	if (csi2rx->count)
+		csi2rx_start(csi2rx);
+	mutex_unlock(&csi2rx->lock);
+	return 0;
+}
+
 static int csi2rx_probe(struct platform_device *pdev)
 {
 	struct csi2rx_priv *csi2rx;
@@ -705,6 +738,7 @@ static int csi2rx_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_cleanup;
 
+	pm_runtime_enable(csi2rx->dev);
 	ret = v4l2_async_register_subdev(&csi2rx->subdev);
 	if (ret < 0)
 		goto err_free_state;
@@ -719,6 +753,7 @@ static int csi2rx_probe(struct platform_device *pdev)
 
 err_free_state:
 	v4l2_subdev_cleanup(&csi2rx->subdev);
+	pm_runtime_disable(csi2rx->dev);
 err_cleanup:
 	v4l2_async_nf_unregister(&csi2rx->notifier);
 	v4l2_async_nf_cleanup(&csi2rx->notifier);
@@ -737,9 +772,14 @@ static void csi2rx_remove(struct platform_device *pdev)
 	v4l2_async_unregister_subdev(&csi2rx->subdev);
 	v4l2_subdev_cleanup(&csi2rx->subdev);
 	media_entity_cleanup(&csi2rx->subdev.entity);
+	pm_runtime_disable(csi2rx->dev);
 	kfree(csi2rx);
 }
 
+static const struct dev_pm_ops csi2rx_pm_ops = {
+	SET_RUNTIME_PM_OPS(csi2rx_suspend, csi2rx_resume, NULL)
+};
+
 static const struct of_device_id csi2rx_of_table[] = {
 	{ .compatible = "starfive,jh7110-csi2rx" },
 	{ .compatible = "cdns,csi2rx" },
@@ -754,6 +794,7 @@ static struct platform_driver csi2rx_driver = {
 	.driver	= {
 		.name		= "cdns-csi2rx",
 		.of_match_table	= csi2rx_of_table,
+		.pm		= &csi2rx_pm_ops,
 	},
 };
 module_platform_driver(csi2rx_driver);
-- 
2.25.1