From e3b4d10cc057522353c4a02f2f90dca6a52e006f Mon Sep 17 00:00:00 2001 From: Petr Cvek Date: Mon, 24 Apr 2017 22:51:58 -0300 Subject: [PATCH] [media] pxa_camera: fix module remove codepath for v4l2 clock The conversion from soc_camera omitted a correct handling of the clock gating for a sensor. When the pxa_camera driver module was removed it tried to unregister clk, but this caused a similar warning: WARNING: CPU: 0 PID: 6740 at drivers/media/v4l2-core/v4l2-clk.c:278 v4l2_clk_unregister(): Refusing to unregister ref-counted 0-0030 clock! The clock was at time still refcounted by the sensor driver. Before the removing of the pxa_camera the clock must be dropped by the sensor driver. This should be triggered by v4l2_async_notifier_unregister() call which removes sensor driver module too, calls unbind() function and then tries to probe sensor driver again. Inside unbind() we can safely unregister the v4l2 clock as the sensor driver got removed. The original v4l2_clk_unregister() should be put inside test as the clock can be already unregistered from unbind(). If there was not any bound sensor the clock is still present. The codepath is practically a copy from the old soc_camera. The bug was tested with a pxa_camera+ov9640 combination during the conversion of the ov9640 from the soc_camera. Signed-off-by: Petr Cvek Tested-by: Robert Jarzmik Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- drivers/media/platform/pxa_camera.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/media/platform/pxa_camera.c b/drivers/media/platform/pxa_camera.c index 929006f65cc7..6615f80fe059 100644 --- a/drivers/media/platform/pxa_camera.c +++ b/drivers/media/platform/pxa_camera.c @@ -2177,6 +2177,12 @@ static void pxa_camera_sensor_unbind(struct v4l2_async_notifier *notifier, pxa_dma_stop_channels(pcdev); pxa_camera_destroy_formats(pcdev); + + if (pcdev->mclk_clk) { + v4l2_clk_unregister(pcdev->mclk_clk); + pcdev->mclk_clk = NULL; + } + video_unregister_device(&pcdev->vdev); pcdev->sensor = NULL; @@ -2501,7 +2507,13 @@ static int pxa_camera_remove(struct platform_device *pdev) dma_release_channel(pcdev->dma_chans[1]); dma_release_channel(pcdev->dma_chans[2]); - v4l2_clk_unregister(pcdev->mclk_clk); + v4l2_async_notifier_unregister(&pcdev->notifier); + + if (pcdev->mclk_clk) { + v4l2_clk_unregister(pcdev->mclk_clk); + pcdev->mclk_clk = NULL; + } + v4l2_device_unregister(&pcdev->v4l2_dev); dev_info(&pdev->dev, "PXA Camera driver unloaded\n");