Hi Guennadi,

Thanks for the patch.

On Wednesday 26 December 2012 18:49:07 Guennadi Liakhovetski wrote:
> Instead of centrally enabling and disabling subdevice master clocks in
> soc-camera core, let subdevice drivers do that themselves, using the
> V4L2 clock API and soc-camera convenience wrappers.
> 
> Signed-off-by: Guennadi Liakhovetski <g.liakhovet...@gmx.de>
> ---
>  drivers/media/i2c/soc_camera/imx074.c              |   18 ++-
>  drivers/media/i2c/soc_camera/mt9m001.c             |   17 ++-
>  drivers/media/i2c/soc_camera/mt9m111.c             |   20 ++-
>  drivers/media/i2c/soc_camera/mt9t031.c             |   19 ++-
>  drivers/media/i2c/soc_camera/mt9t112.c             |   19 ++-
>  drivers/media/i2c/soc_camera/mt9v022.c             |   17 ++-
>  drivers/media/i2c/soc_camera/ov2640.c              |   19 ++-
>  drivers/media/i2c/soc_camera/ov5642.c              |   20 ++-
>  drivers/media/i2c/soc_camera/ov6650.c              |   17 ++-
>  drivers/media/i2c/soc_camera/ov772x.c              |   15 ++-
>  drivers/media/i2c/soc_camera/ov9640.c              |   17 ++-
>  drivers/media/i2c/soc_camera/ov9640.h              |    1 +
>  drivers/media/i2c/soc_camera/ov9740.c              |   18 ++-
>  drivers/media/i2c/soc_camera/rj54n1cb0c.c          |   17 ++-
>  drivers/media/i2c/soc_camera/tw9910.c              |   18 ++-
>  drivers/media/platform/soc_camera/soc_camera.c     |  173  ++++++++++++----
>  .../platform/soc_camera/soc_camera_platform.c      |    2 +-
>  include/media/soc_camera.h                         |   13 +-
>  18 files changed, 356 insertions(+), 84 deletions(-)

[snip]

> diff --git a/drivers/media/platform/soc_camera/soc_camera.c
> b/drivers/media/platform/soc_camera/soc_camera.c index 0b6ddff..a9e6f01
> 100644
> --- a/drivers/media/platform/soc_camera/soc_camera.c
> +++ b/drivers/media/platform/soc_camera/soc_camera.c

[snip]

> @@ -1068,6 +1091,57 @@ static void scan_add_host(struct soc_camera_host
> *ici) mutex_unlock(&list_lock);
>  }
> 
> +/*
> + * It is invalid to call v4l2_clk_enable() after a successful probing
> + * asynchronously outside of V4L2 operations, i.e. with .host_lock not
> held.
> + */
> +static int soc_camera_clk_enable(struct v4l2_clk *clk)
> +{
> +     struct soc_camera_device *icd = clk->priv;
> +     struct soc_camera_host *ici;
> +
> +     if (!icd || !icd->parent)
> +             return -ENODEV;
> +
> +     ici = to_soc_camera_host(icd->parent);
> +
> +     if (!try_module_get(ici->ops->owner))
> +             return -ENODEV;
> +
> +     /*
> +      * If a different client is currently being probed, the host will tell
> +      * you to go
> +      */
> +     return ici->ops->add(icd);
> +}
> +
> +static void soc_camera_clk_disable(struct v4l2_clk *clk)
> +{
> +     struct soc_camera_device *icd = clk->priv;
> +     struct soc_camera_host *ici;
> +
> +     if (!icd || !icd->parent)
> +             return;
> +
> +     ici = to_soc_camera_host(icd->parent);
> +
> +     ici->ops->remove(icd);
> +
> +     module_put(ici->ops->owner);
> +}
> +
> +/*
> + * Eventually, it would be more logical to make the respective host the
> clock
> + * owner, but then we would have to copy this struct for each ici. Besides,
> it
> + * would introduce the circular dependency problem, unless we port all
> client
> + * drivers to release the clock, when not in use.
> + */

Won't we have to solve this problem eventually ? This should probably be put 
on the agenda of the next V4L2 workshop/summit.

> +static const struct v4l2_clk_ops soc_camera_clk_ops = {
> +     .owner = THIS_MODULE,
> +     .enable = soc_camera_clk_enable,
> +     .disable = soc_camera_clk_disable,
> +};
> +
>  #ifdef CONFIG_I2C_BOARDINFO
>  static int soc_camera_init_i2c(struct soc_camera_device *icd,
>                              struct soc_camera_desc *sdesc)
> @@ -1077,19 +1151,33 @@ static int soc_camera_init_i2c(struct
> soc_camera_device *icd, struct soc_camera_host_desc *shd =
> &sdesc->host_desc;
>       struct i2c_adapter *adap = i2c_get_adapter(shd->i2c_adapter_id);
>       struct v4l2_subdev *subdev;
> +     char clk_name[V4L2_SUBDEV_NAME_SIZE];
> +     int ret;
> 
>       if (!adap) {
>               dev_err(icd->pdev, "Cannot get I2C adapter #%d. No driver?\n",
>                       shd->i2c_adapter_id);
> -             goto ei2cga;
> +             return -ENODEV;
>       }
> 
>       shd->board_info->platform_data = &sdesc->subdev_desc;
> 
> +     snprintf(clk_name, sizeof(clk_name), "%s %d-%04x",
> +              shd->board_info->type,
> +              shd->i2c_adapter_id, shd->board_info->addr);
> +
> +     icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, "mclk", 
> icd);

I don't think you should hardcode the clock name to "mclk". The common clock 
framework use a client-specific clock name when requesting a clock, it would 
be better to use a similar mechanism.

> +     if (IS_ERR(icd->clk)) {
> +             ret = PTR_ERR(icd->clk);
> +             goto eclkreg;
> +     }
> +
>       subdev = v4l2_i2c_new_subdev_board(&ici->v4l2_dev, adap,
>                               shd->board_info, NULL);
> -     if (!subdev)
> +     if (!subdev) {
> +             ret = -ENODEV;
>               goto ei2cnd;
> +     }
> 
>       client = v4l2_get_subdevdata(subdev);
> 

-- 
Regards,

Laurent Pinchart

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