[PATCH 1/3] media: atmel-isi: move the peripheral clock to start/stop_stream() function
From: laurent.pinchart@ideasonboard.com (Laurent Pinchart)
Date: 2015-03-05 10:39:37
Also in:
linux-media
Hi Josh, Thank you for the patch. On Thursday 05 March 2015 13:00:59 Josh Wu wrote:
As the clock_start/stop() use to control the mclk for the sensor not the ISI peripheral clock. So we move them to start/stop_stream() function.
Then the driver will access registers with the peripheral clock disabled, for instance in isi_camera_set_fmt() (calling configure_geometry), isi_camera_set_bus_param() or atmel_isi_probe(). Isn't that a problem ? Or are all registers guaranteed to be accessible (and retained) when the clock is disabled ?
quoted hunk ↗ jump to hunk
Signed-off-by: Josh Wu <redacted> --- drivers/media/platform/soc_camera/atmel-isi.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)diff --git a/drivers/media/platform/soc_camera/atmel-isi.cb/drivers/media/platform/soc_camera/atmel-isi.c index 1208818..eb179e7 100644--- a/drivers/media/platform/soc_camera/atmel-isi.c +++ b/drivers/media/platform/soc_camera/atmel-isi.c@@ -386,6 +386,10 @@ static int start_streaming(struct vb2_queue *vq,unsigned int count) struct atmel_isi *isi = ici->priv; int ret; + ret = clk_prepare_enable(isi->pclk); + if (ret) + return ret; + /* Reset ISI */ ret = atmel_isi_wait_status(isi, WAIT_ISI_RESET); if (ret < 0) {@@ -445,6 +449,8 @@ static void stop_streaming(struct vb2_queue *vq) ret = atmel_isi_wait_status(isi, WAIT_ISI_DISABLE); if (ret < 0) dev_err(icd->parent, "Disable ISI timed out\n"); + + clk_disable_unprepare(isi->pclk); } static struct vb2_ops isi_video_qops = {@@ -723,14 +729,9 @@ static int isi_camera_clock_start(structsoc_camera_host *ici) struct atmel_isi *isi = ici->priv; int ret; - ret = clk_prepare_enable(isi->pclk); - if (ret) - return ret; - if (!IS_ERR(isi->mck)) { ret = clk_prepare_enable(isi->mck); if (ret) { - clk_disable_unprepare(isi->pclk); return ret; } }@@ -745,7 +746,6 @@ static void isi_camera_clock_stop(struct soc_camera_host*ici) if (!IS_ERR(isi->mck)) clk_disable_unprepare(isi->mck); - clk_disable_unprepare(isi->pclk); } static unsigned int isi_camera_poll(struct file *file, poll_table *pt)
-- Regards, Laurent Pinchart