Re: [PATCH v6] media: platform: add VPFE capture driver support for AM437X

From: Hans Verkuil
Date: Tue Dec 09 2014 - 15:49:55 EST


On 12/09/2014 08:43 PM, Lad, Prabhakar wrote:
> From: Benoit Parrot <bparrot@xxxxxx>
>
> This patch adds Video Processing Front End (VPFE) driver for
> AM437X family of devices
> Driver supports the following:
> - V4L2 API using MMAP buffer access based on videobuf2 api
> - Asynchronous sensor/decoder sub device registration
> - DT support
>
> Signed-off-by: Benoit Parrot <bparrot@xxxxxx>
> Signed-off-by: Darren Etheridge <detheridge@xxxxxx>
> Signed-off-by: Lad, Prabhakar <prabhakar.csengg@xxxxxxxxx>
> ---
> Changes for v6:
> 1: Fixed review comments pointed Hans, fixing race condition.
>
> v5: https://patchwork.kernel.org/patch/5459311/
> v4: https://patchwork.kernel.org/patch/5449211/
> v3: https://patchwork.kernel.org/patch/5434291/
> v2: https://patchwork.kernel.org/patch/5425631/
> v1: https://patchwork.kernel.org/patch/5362661/
>
> .../devicetree/bindings/media/ti-am437x-vpfe.txt | 61 +
> MAINTAINERS | 9 +
> drivers/media/platform/Kconfig | 1 +
> drivers/media/platform/Makefile | 2 +
> drivers/media/platform/am437x/Kconfig | 11 +
> drivers/media/platform/am437x/Makefile | 3 +
> drivers/media/platform/am437x/am437x-vpfe.c | 2777 ++++++++++++++++++++
> drivers/media/platform/am437x/am437x-vpfe.h | 283 ++
> drivers/media/platform/am437x/am437x-vpfe_regs.h | 140 +
> include/uapi/linux/Kbuild | 1 +
> include/uapi/linux/am437x-vpfe.h | 122 +
> 11 files changed, 3410 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/media/ti-am437x-vpfe.txt
> create mode 100644 drivers/media/platform/am437x/Kconfig
> create mode 100644 drivers/media/platform/am437x/Makefile
> create mode 100644 drivers/media/platform/am437x/am437x-vpfe.c
> create mode 100644 drivers/media/platform/am437x/am437x-vpfe.h
> create mode 100644 drivers/media/platform/am437x/am437x-vpfe_regs.h
> create mode 100644 include/uapi/linux/am437x-vpfe.h
>

<snip>

> +/*
> + * vpfe_release : This function is based on the vb2_fop_release
> + * helper function.
> + * It has been augmented to handle module power management,
> + * by disabling/enabling h/w module fcntl clock when necessary.
> + */
> +static int vpfe_release(struct file *file)
> +{
> + struct vpfe_device *vpfe = video_drvdata(file);
> + int ret;
> +
> + mutex_lock(&vpfe->lock);
> +
> + ret = _vb2_fop_release(file, NULL);
> + if (v4l2_fh_is_singular_file(file))
> + vpfe_ccdc_close(&vpfe->ccdc, vpfe->pdev);

This function seems cursed since your _vb2_fop_release call should
go *after* the v4l2_fh_is_singular_file() check.

I've fixed that in the patch in my pull request, so there is no need
for a v7. I know you've tested that since that was the order in your v5
version of this patch.

Regards,

Hans

> +
> + mutex_unlock(&vpfe->lock);
> +
> + return ret;
> +}
> +
> +/*
> + * vpfe_open : This function is based on the v4l2_fh_open helper function.
> + * It has been augmented to handle module power management,
> + * by disabling/enabling h/w module fcntl clock when necessary.
> + */
> +static int vpfe_open(struct file *file)
> +{
> + struct vpfe_device *vpfe = video_drvdata(file);
> + int ret;
> +
> + mutex_lock(&vpfe->lock);
> +
> + ret = v4l2_fh_open(file);
> + if (ret) {
> + vpfe_err(vpfe, "v4l2_fh_open failed\n");
> + goto unlock;
> + }
> +
> + if (!v4l2_fh_is_singular_file(file))
> + goto unlock;
> +
> + if (vpfe_initialize_device(vpfe)) {
> + v4l2_fh_release(file);
> + ret = -ENODEV;
> + }
> +
> +unlock:
> + mutex_unlock(&vpfe->lock);
> + return ret;
> +}

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