linux-kernel - [PATCH v5 12/14] media: mt9m114: Drop start-, stop-streaming sequence from initialize

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Message-Id: <20251230-mt9m114-atomisp-v5-12-763539e76094@oss.qualcomm.com>
Date: Tue, 30 Dec 2025 18:03:09 +0100
From: Hans de Goede <johannes.goede@....qualcomm.com>
To: Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Hans de Goede <johannes.goede@....qualcomm.com>
Subject: [PATCH v5 12/14] media: mt9m114: Drop start-, stop-streaming
 sequence from initialize

Drop the start-, stop-streaming sequence from initialize.

When streaming is started with a runtime-suspended sensor,
mt9m114_start_streaming() will runtime-resume the sensor which calls
mt9m114_initialize() immediately followed by calling
mt9m114_set_state(ENTER_CONFIG_CHANGE).

This results in the following state changes in quick succession:

mt9m114_set_state(ENTER_CONFIG_CHANGE) -> transitions to STREAMING
mt9m114_set_state(ENTER_SUSPEND)       -> transitions to SUSPENDED
mt9m114_set_state(ENTER_CONFIG_CHANGE) -> transitions to STREAMING

these quick state changes confuses the CSI receiver on atomisp devices
causing streaming to not work.

Drop the state changes from mt9m114_initialize() and move
the mt9m114_initialize() call to mt9m114_start_streaming()
so that only a single mt9m114_set_state(ENTER_CONFIG_CHANGE) call
is made when streaming is started with a runtime-suspend sensor.

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Signed-off-by: Hans de Goede <johannes.goede@....qualcomm.com>
---
Changes in v5:
- Drop "and identify it " from comment in probe()

Changes in v4:
- Move the mt9m114_initialize() call to mt9m114_start_streaming()
  and drop the config_change_pending flag
---
 drivers/media/i2c/mt9m114.c | 33 +++++++--------------------------
 1 file changed, 7 insertions(+), 26 deletions(-)

diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c
index 5e0fbc34921023e1e7a69ec3d098f936eba93ebb..18fcf1a105a4268a501f517a155f12def0753929 100644
--- a/drivers/media/i2c/mt9m114.c
+++ b/drivers/media/i2c/mt9m114.c
@@ -789,14 +789,6 @@ static int mt9m114_initialize(struct mt9m114 *sensor)
 	if (ret < 0)
 		return ret;
 
-	ret = mt9m114_set_state(sensor, MT9M114_SYS_STATE_ENTER_CONFIG_CHANGE);
-	if (ret < 0)
-		return ret;
-
-	ret = mt9m114_set_state(sensor, MT9M114_SYS_STATE_ENTER_SUSPEND);
-	if (ret < 0)
-		return ret;
-
 	return 0;
 }
 
@@ -967,6 +959,10 @@ static int mt9m114_start_streaming(struct mt9m114 *sensor,
 	if (ret)
 		return ret;
 
+	ret = mt9m114_initialize(sensor);
+	if (ret)
+		goto error;
+
 	ret = mt9m114_configure_ifp(sensor, ifp_state);
 	if (ret)
 		goto error;
@@ -2318,19 +2314,8 @@ static int __maybe_unused mt9m114_runtime_resume(struct device *dev)
 {
 	struct v4l2_subdev *sd = dev_get_drvdata(dev);
 	struct mt9m114 *sensor = ifp_to_mt9m114(sd);
-	int ret;
 
-	ret = mt9m114_power_on(sensor);
-	if (ret)
-		return ret;
-
-	ret = mt9m114_initialize(sensor);
-	if (ret) {
-		mt9m114_power_off(sensor);
-		return ret;
-	}
-
-	return 0;
+	return mt9m114_power_on(sensor);
 }
 
 static int __maybe_unused mt9m114_runtime_suspend(struct device *dev)
@@ -2574,8 +2559,8 @@ static int mt9m114_probe(struct i2c_client *client)
 	/*
 	 * Identify the sensor. The driver supports runtime PM, but needs to
 	 * work when runtime PM is disabled in the kernel. To that end, power
-	 * the sensor on manually here, and initialize it after identification
-	 * to reach the same state as if resumed through runtime PM.
+	 * the sensor on manually here to reach the same state as if resumed
+	 * through runtime PM.
 	 */
 	ret = mt9m114_power_on(sensor);
 	if (ret < 0) {
@@ -2587,10 +2572,6 @@ static int mt9m114_probe(struct i2c_client *client)
 	if (ret < 0)
 		goto error_power_off;
 
-	ret = mt9m114_initialize(sensor);
-	if (ret < 0)
-		goto error_power_off;
-
 	/*
 	 * Enable runtime PM with autosuspend. As the device has been powered
 	 * manually, mark it as active, and increase the usage count without

-- 
2.52.0