Hi Guennadi,
Thank you for the patch. I like the approach.
On Friday 02 January 2015 12:48:43 Guennadi Liakhovetski wrote:
> V4L2 clocks, e.g. used by camera sensors for their master clock, do not
> have to be supplied by a different V4L2 driver, they can also be
> supplied by an independent source. In this case the standart kernel
> clock API should be used to handle such clocks. This patch adds support
> for such cases.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> ---
> drivers/media/v4l2-core/v4l2-clk.c | 76 ++++++++++++++++++++++++++++++-----
> include/media/v4l2-clk.h | 2 +
> 2 files changed, 68 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-clk.c
> b/drivers/media/v4l2-core/v4l2-clk.c index c210906..693e5a0 100644
> --- a/drivers/media/v4l2-core/v4l2-clk.c
> +++ b/drivers/media/v4l2-core/v4l2-clk.c
> @@ -9,6 +9,7 @@
> */
>
> #include <linux/atomic.h>
> +#include <linux/clk.h>
> #include <linux/device.h>
> #include <linux/errno.h>
> #include <linux/list.h>
> @@ -39,9 +40,24 @@ static struct v4l2_clk *v4l2_clk_find(const char *dev_id,
> const char *id) return ERR_PTR(-ENODEV);
> }
>
> +static int v4l2_clk_add(struct v4l2_clk *clk, const char *dev_id,
> + const char *id)
> +{
> + mutex_lock(&clk_lock);
> + if (!IS_ERR(v4l2_clk_find(dev_id, id))) {
> + mutex_unlock(&clk_lock);
> + return -EEXIST;
> + }
> + list_add_tail(&clk->list, &clk_list);
> + mutex_unlock(&clk_lock);
> +
> + return 0;
> +}
> +
> struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id)
> {
> struct v4l2_clk *clk;
> + struct clk *ccf_clk = clk_get(dev, id);
>
> mutex_lock(&clk_lock);
> clk = v4l2_clk_find(dev_name(dev), id);
> @@ -50,6 +66,22 @@ struct v4l2_clk *v4l2_clk_get(struct device *dev, const
> char *id) atomic_inc(&clk->use_count);
> mutex_unlock(&clk_lock);
Shouldn't we start by CCF and then fall back to V4L2 clocks ?
> + if (!IS_ERR(ccf_clk) && IS_ERR(clk)) {
> + /* not yet on the list */
> + clk = kzalloc(sizeof(struct v4l2_clk), GFP_KERNEL);
> + if (clk)
> + clk->id = kstrdup(id, GFP_KERNEL);
> + if (!clk || !clk->id) {
> + kfree(clk);
> + clk_put(ccf_clk);
> + return ERR_PTR(-ENOMEM);
> + }
> + clk->clk = ccf_clk;
> + atomic_set(&clk->use_count, 1);
> +
> + v4l2_clk_add(clk, dev_name(dev), id);
I don't think there's a need to add this clock to the clk_list. As all
operations are delegated to CCF, and as CCF implements proper refcounting, we
can just create one v4l2_clk wrapper instance for every call to
v4l2_clk_get().
> + }
> +
> return clk;
> }
> EXPORT_SYMBOL(v4l2_clk_get);
> @@ -67,6 +99,15 @@ void v4l2_clk_put(struct v4l2_clk *clk)
> if (tmp == clk)
> atomic_dec(&clk->use_count);
>
> + if (clk->clk) {
> + clk_put(clk->clk);
> + if (!atomic_read(&clk->use_count)) {
> + list_del(&clk->list);
> + kfree(clk->id);
> + kfree(clk);
> + }
> + }
> +
> mutex_unlock(&clk_lock);
> }
> EXPORT_SYMBOL(v4l2_clk_put);
> @@ -98,8 +139,12 @@ static void v4l2_clk_unlock_driver(struct v4l2_clk *clk)
>
> int v4l2_clk_enable(struct v4l2_clk *clk)
> {
> - int ret = v4l2_clk_lock_driver(clk);
> + int ret;
> +
> + if (clk->clk)
> + return clk_enable(clk->clk);
>
> + ret = v4l2_clk_lock_driver(clk);
> if (ret < 0)
> return ret;
>
> @@ -125,6 +170,9 @@ void v4l2_clk_disable(struct v4l2_clk *clk)
> {
> int enable;
>
> + if (clk->clk)
> + return clk_disable(clk->clk);
> +
> mutex_lock(&clk->lock);
>
> enable = --clk->enable;
> @@ -142,8 +190,12 @@ EXPORT_SYMBOL(v4l2_clk_disable);
>
> unsigned long v4l2_clk_get_rate(struct v4l2_clk *clk)
> {
> - int ret = v4l2_clk_lock_driver(clk);
> + int ret;
>
> + if (clk->clk)
> + return clk_get_rate(clk->clk);
> +
> + ret = v4l2_clk_lock_driver(clk);
> if (ret < 0)
> return ret;
>
> @@ -162,7 +214,16 @@ EXPORT_SYMBOL(v4l2_clk_get_rate);
>
> int v4l2_clk_set_rate(struct v4l2_clk *clk, unsigned long rate)
> {
> - int ret = v4l2_clk_lock_driver(clk);
> + int ret;
> +
> + if (clk->clk) {
> + long r = clk_round_rate(clk->clk, rate);
> + if (r < 0)
> + return r;
> + return clk_set_rate(clk->clk, r);
> + }
> +
> + ret = v4l2_clk_lock_driver(clk);
>
> if (ret < 0)
> return ret;
> @@ -204,14 +265,9 @@ struct v4l2_clk *v4l2_clk_register(const struct
> v4l2_clk_ops *ops, atomic_set(&clk->use_count, 0);
> mutex_init(&clk->lock);
>
> - mutex_lock(&clk_lock);
> - if (!IS_ERR(v4l2_clk_find(dev_id, NULL))) {
> - mutex_unlock(&clk_lock);
> - ret = -EEXIST;
> + ret = v4l2_clk_add(clk, dev_id, NULL);
> + if (ret < 0)
> goto eexist;
> - }
> - list_add_tail(&clk->list, &clk_list);
> - mutex_unlock(&clk_lock);
>
> return clk;
>
> diff --git a/include/media/v4l2-clk.h b/include/media/v4l2-clk.h
> index 8f06967..4402b2d 100644
> --- a/include/media/v4l2-clk.h
> +++ b/include/media/v4l2-clk.h
> @@ -22,6 +22,7 @@
> struct module;
> struct device;
>
> +struct clk;
> struct v4l2_clk {
> struct list_head list;
> const struct v4l2_clk_ops *ops;
> @@ -30,6 +31,7 @@ struct v4l2_clk {
> int enable;
> struct mutex lock; /* Protect the enable count */
> atomic_t use_count;
> + struct clk *clk;
> void *priv;
> };
--
Regards,
Laurent Pinchart
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