On Mon, 5 Jan 2015, Josh Wu wrote: > Hi, Guennadi > > On 1/3/2015 4:18 AM, Guennadi Liakhovetski wrote: > > From aeaee56e04d023f3a019d2595ef5128015acdb06 Mon Sep 17 00:00:00 2001 > > From: Guennadi Liakhovetski <g.liakhovet...@gmx.de> > > Date: Fri, 2 Jan 2015 12:26:41 +0100 > > Subject: [PATCH 2/2] V4L2: add CCF support to the v4l2_clk API > > > > 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.liakhovet...@gmx.de> > > --- > > > > Hi Laurent, > > Thanks for the comment. The idea of allocating a new object for each "get" > > operation seems a bit weird to me, and completely trusting the user is a > > bit scary... :) But yes, it can work this way too, I think, and the user > > can screw either way too, anyway. So, here comes a v2. Something like > > this? > > > > v2: don't add CCF-related clocks on the global list, just allocate a new > > instance on each v4l2_clk_get() > > > > drivers/media/v4l2-core/v4l2-clk.c | 45 > > +++++++++++++++++++++++++++++++++++--- > > include/media/v4l2-clk.h | 2 ++ > > 2 files changed, 44 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/media/v4l2-core/v4l2-clk.c > > b/drivers/media/v4l2-core/v4l2-clk.c > > index c210906..f5d1688 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> > > @@ -42,6 +43,18 @@ static struct v4l2_clk *v4l2_clk_find(const char *dev_id, > > const char *id) > > struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id) > > { > > struct v4l2_clk *clk; > > + struct clk *ccf_clk = clk_get(dev, id); > We need to check whether the 'id' is NULL, otherwise there is no error > reported if we use IS_ERR(ccf_clk).
? Sorry, don't understand. AFAIK, id = NULL is absolutely valid, no need to check for it explicitly. However, it just occurs to me, that we probably need to change the below test > Best Regards, > Josh Wu > > > + > > + if (!IS_ERR(ccf_clk)) { to > > + if (!IS_ERR_OR_NULL(ccf_clk)) { to cover the case when CCF isn't built at all and a stub is used. In that case it's probably better to fall back to the V4L2 clock emulation. Thanks Guennadi > > + clk = kzalloc(sizeof(struct v4l2_clk), GFP_KERNEL); > > + if (!clk) { > > + clk_put(ccf_clk); > > + return ERR_PTR(-ENOMEM); > > + } > > + clk->clk = ccf_clk; > > + > > + return clk; > > + } > > mutex_lock(&clk_lock); > > clk = v4l2_clk_find(dev_name(dev), id); > > @@ -61,6 +74,12 @@ void v4l2_clk_put(struct v4l2_clk *clk) > > if (IS_ERR(clk)) > > return; > > + if (clk->clk) { > > + clk_put(clk->clk); > > + kfree(clk); > > + return; > > + } > > + > > mutex_lock(&clk_lock); > > list_for_each_entry(tmp, &clk_list, list) > > @@ -98,8 +117,12 @@ 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 +148,9 @@ 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 +168,12 @@ 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 +192,16 @@ 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; > > 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; > > }; > > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html