Re: [PATCH 1/2] V4L: remove clock name from v4l2_clk API

[Josh Wu <josh.wu@xxxxxxxxx>]

Hi, Guennadi

On 1/5/2015 5:28 PM, Guennadi Liakhovetski wrote:
> Hi Josh,
>
> On Mon, 5 Jan 2015, Josh Wu wrote:
>
> > Hi, Guennadi
> >
> > On 1/2/2015 7:48 PM, Guennadi Liakhovetski wrote:
> > > All uses of the v4l2_clk API so far only register one clock with a fixed
> > > name. This allows us to get rid of it, which also will make CCF and DT
> > > integration easier.
> > This patch not register a v4l2_clk with name: "mclk". So this will break all
> > the i2c sensors that used the v4l2 clock "mclk".
> > To make those drivers work, we need change all lines from:
> >     v4l2_clk_get(&client->dev, "mclk");
> > to:
> >     v4l2_clk_get(&client->dev, NULL);
> >
> > Am I understanding correctly?
> No, it's the opposite. Clock consumers should request clock names,
> according to their datasheets. In ov2640 case it's xvclk. For v4l2_clk the
> name will simply be ignored. But it will be used to try to get a CCF clock
> before falling back to V4L2 clocks.
Okay, you mean I only need request xvclk clock via call v4l2_clk_get() 
in ov2640 driver. right?
So the question is how do we operation the camera host's 
.clock_start/stop()? Which is by v4l2_clk_get() old "mclk".

hmm, wait. Since this part is not belong to ov2640, I think we should 
move this part code to soc_camera.c 's function: soc_camera_power_on().
or do I miss anything?

> Thanks
> Guennadi

Best Regards,
Josh Wu
> > if yes, I'd like to define a SOC_CAMERA_HOST_CLK_ID in soc_camera.h, and all
> > code will use:
> >      v4l2_clk_get(&client->dev, SOC_CAMERA_HOST_CLK_ID);
> >
> > > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> > > ---
> > >    drivers/media/platform/soc_camera/soc_camera.c |  6 +++---
> > >    drivers/media/usb/em28xx/em28xx-camera.c       |  2 +-
> > >    drivers/media/v4l2-core/v4l2-clk.c             | 24
> > > +++++++++++-------------
> > >    include/media/v4l2-clk.h                       |  7 +++----
> > >    4 files changed, 18 insertions(+), 21 deletions(-)
> > >
> > > diff --git a/drivers/media/platform/soc_camera/soc_camera.c
> > > b/drivers/media/platform/soc_camera/soc_camera.c
> > > index f4be2a1..ce192b6 100644
> > > --- a/drivers/media/platform/soc_camera/soc_camera.c
> > > +++ b/drivers/media/platform/soc_camera/soc_camera.c
> > > @@ -1380,7 +1380,7 @@ static int soc_camera_i2c_init(struct
> > > soc_camera_device *icd,
> > >    	snprintf(clk_name, sizeof(clk_name), "%d-%04x",
> > >    		 shd->i2c_adapter_id, shd->board_info->addr);
> > >    -	icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, "mclk",
> > > icd);
> > > +	icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, icd);
> > >    	if (IS_ERR(icd->clk)) {
> > >    		ret = PTR_ERR(icd->clk);
> > >    		goto eclkreg;
> > > @@ -1561,7 +1561,7 @@ static int scan_async_group(struct soc_camera_host
> > > *ici,
> > >    	snprintf(clk_name, sizeof(clk_name), "%d-%04x",
> > >    		 sasd->asd.match.i2c.adapter_id, sasd->asd.match.i2c.address);
> > >    -	icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, "mclk",
> > > icd);
> > > +	icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, icd);
> > >    	if (IS_ERR(icd->clk)) {
> > >    		ret = PTR_ERR(icd->clk);
> > >    		goto eclkreg;
> > > @@ -1666,7 +1666,7 @@ static int soc_of_bind(struct soc_camera_host *ici,
> > >    		snprintf(clk_name, sizeof(clk_name), "of-%s",
> > >    			 of_node_full_name(remote));
> > >    -	icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, "mclk",
> > > icd);
> > > +	icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, icd);
> > >    	if (IS_ERR(icd->clk)) {
> > >    		ret = PTR_ERR(icd->clk);
> > >    		goto eclkreg;
> > > diff --git a/drivers/media/usb/em28xx/em28xx-camera.c
> > > b/drivers/media/usb/em28xx/em28xx-camera.c
> > > index 7be661f..a4b22c2 100644
> > > --- a/drivers/media/usb/em28xx/em28xx-camera.c
> > > +++ b/drivers/media/usb/em28xx/em28xx-camera.c
> > > @@ -330,7 +330,7 @@ int em28xx_init_camera(struct em28xx *dev)
> > >      	v4l2_clk_name_i2c(clk_name, sizeof(clk_name),
> > >    			  i2c_adapter_id(adap), client->addr);
> > > -	v4l2->clk = v4l2_clk_register_fixed(clk_name, "mclk", -EINVAL);
> > > +	v4l2->clk = v4l2_clk_register_fixed(clk_name, -EINVAL);
> > >    	if (IS_ERR(v4l2->clk))
> > >    		return PTR_ERR(v4l2->clk);
> > >    diff --git a/drivers/media/v4l2-core/v4l2-clk.c
> > > b/drivers/media/v4l2-core/v4l2-clk.c
> > > index e18cc04..c210906 100644
> > > --- a/drivers/media/v4l2-core/v4l2-clk.c
> > > +++ b/drivers/media/v4l2-core/v4l2-clk.c
> > > @@ -31,7 +31,8 @@ static struct v4l2_clk *v4l2_clk_find(const char *dev_id,
> > > const char *id)
> > >    		if (strcmp(dev_id, clk->dev_id))
> > >    			continue;
> > >    -		if (!id || !clk->id || !strcmp(clk->id, id))
> > > +		if ((!id && !clk->id) ||
> > > +		    (id && clk->id && !strcmp(clk->id, id)))
> > >    			return clk;
> > >    	}
> > >    @@ -127,8 +128,8 @@ void v4l2_clk_disable(struct v4l2_clk *clk)
> > >    	mutex_lock(&clk->lock);
> > >      	enable = --clk->enable;
> > > -	if (WARN(enable < 0, "Unbalanced %s() on %s:%s!\n", __func__,
> > > -		 clk->dev_id, clk->id))
> > > +	if (WARN(enable < 0, "Unbalanced %s() on %s!\n", __func__,
> > > +		 clk->dev_id))
> > >    		clk->enable++;
> > >    	else if (!enable && clk->ops->disable)
> > >    		clk->ops->disable(clk);
> > > @@ -181,7 +182,7 @@ EXPORT_SYMBOL(v4l2_clk_set_rate);
> > >      struct v4l2_clk *v4l2_clk_register(const struct v4l2_clk_ops *ops,
> > >    				   const char *dev_id,
> > > -				   const char *id, void *priv)
> > > +				   void *priv)
> > >    {
> > >    	struct v4l2_clk *clk;
> > >    	int ret;
> > > @@ -193,9 +194,8 @@ struct v4l2_clk *v4l2_clk_register(const struct
> > > v4l2_clk_ops *ops,
> > >    	if (!clk)
> > >    		return ERR_PTR(-ENOMEM);
> > >    -	clk->id = kstrdup(id, GFP_KERNEL);
> > >    	clk->dev_id = kstrdup(dev_id, GFP_KERNEL);
> > > -	if ((id && !clk->id) || !clk->dev_id) {
> > > +	if (!clk->dev_id) {
> > >    		ret = -ENOMEM;
> > >    		goto ealloc;
> > >    	}
> > > @@ -205,7 +205,7 @@ struct v4l2_clk *v4l2_clk_register(const struct
> > > v4l2_clk_ops *ops,
> > >    	mutex_init(&clk->lock);
> > >      	mutex_lock(&clk_lock);
> > > -	if (!IS_ERR(v4l2_clk_find(dev_id, id))) {
> > > +	if (!IS_ERR(v4l2_clk_find(dev_id, NULL))) {
> > So the camera sensor driver should request the v4l2 clock with id is NULL?
> >
> > How about define a SOC_CAMERA_HOST_CLK_ID in soc_camera.h, like:
> >      #define SOC_CAMERA_HOST_CLK_ID    NULL
> >
> > then we can rewrite this block code to:
> >
> >          clk->ops = ops;
> >          clk->priv = priv;
> > +      clk->id = SOC_CAMERA_HOST_CLK_ID;
> >          atomic_set(&clk->use_count, 0);
> >          mutex_init(&clk->lock);
> >
> >          mutex_lock(&clk_lock);
> >          if (!IS_ERR(v4l2_clk_find(dev_id, id))) {
> >          ... ...
> >
> > Best Regards,
> > Josh Wu
> >
> > >    		mutex_unlock(&clk_lock);
> > >    		ret = -EEXIST;
> > >    		goto eexist;
> > > @@ -217,7 +217,6 @@ struct v4l2_clk *v4l2_clk_register(const struct
> > > v4l2_clk_ops *ops,
> > >      eexist:
> > >    ealloc:
> > > -	kfree(clk->id);
> > >    	kfree(clk->dev_id);
> > >    	kfree(clk);
> > >    	return ERR_PTR(ret);
> > > @@ -227,15 +226,14 @@ EXPORT_SYMBOL(v4l2_clk_register);
> > >    void v4l2_clk_unregister(struct v4l2_clk *clk)
> > >    {
> > >    	if (WARN(atomic_read(&clk->use_count),
> > > -		 "%s(): Refusing to unregister ref-counted %s:%s clock!\n",
> > > -		 __func__, clk->dev_id, clk->id))
> > > +		 "%s(): Refusing to unregister ref-counted %s clock!\n",
> > > +		 __func__, clk->dev_id))
> > >    		return;
> > >      	mutex_lock(&clk_lock);
> > >    	list_del(&clk->list);
> > >    	mutex_unlock(&clk_lock);
> > >    -	kfree(clk->id);
> > >    	kfree(clk->dev_id);
> > >    	kfree(clk);
> > >    }
> > > @@ -253,7 +251,7 @@ static unsigned long fixed_get_rate(struct v4l2_clk
> > > *clk)
> > >    }
> > >      struct v4l2_clk *__v4l2_clk_register_fixed(const char *dev_id,
> > > -		const char *id, unsigned long rate, struct module *owner)
> > > +				unsigned long rate, struct module *owner)
> > >    {
> > >    	struct v4l2_clk *clk;
> > >    	struct v4l2_clk_fixed *priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> > > @@ -265,7 +263,7 @@ struct v4l2_clk *__v4l2_clk_register_fixed(const char
> > > *dev_id,
> > >    	priv->ops.get_rate = fixed_get_rate;
> > >    	priv->ops.owner = owner;
> > >    -	clk = v4l2_clk_register(&priv->ops, dev_id, id, priv);
> > > +	clk = v4l2_clk_register(&priv->ops, dev_id, priv);
> > >    	if (IS_ERR(clk))
> > >    		kfree(priv);
> > >    diff --git a/include/media/v4l2-clk.h b/include/media/v4l2-clk.h
> > > index 0b36cc1..8f06967 100644
> > > --- a/include/media/v4l2-clk.h
> > > +++ b/include/media/v4l2-clk.h
> > > @@ -43,7 +43,7 @@ struct v4l2_clk_ops {
> > >      struct v4l2_clk *v4l2_clk_register(const struct v4l2_clk_ops *ops,
> > >    				   const char *dev_name,
> > > -				   const char *name, void *priv);
> > > +				   void *priv);
> > >    void v4l2_clk_unregister(struct v4l2_clk *clk);
> > >    struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id);
> > >    void v4l2_clk_put(struct v4l2_clk *clk);
> > > @@ -55,14 +55,13 @@ int v4l2_clk_set_rate(struct v4l2_clk *clk, unsigned
> > > long rate);
> > >    struct module;
> > >      struct v4l2_clk *__v4l2_clk_register_fixed(const char *dev_id,
> > > -		const char *id, unsigned long rate, struct module *owner);
> > > +			unsigned long rate, struct module *owner);
> > >    void v4l2_clk_unregister_fixed(struct v4l2_clk *clk);
> > >      static inline struct v4l2_clk *v4l2_clk_register_fixed(const char
> > > *dev_id,
> > > -							const char *id,
> > >    							unsigned long rate)
> > >    {
> > > -	return __v4l2_clk_register_fixed(dev_id, id, rate, THIS_MODULE);
> > > +	return __v4l2_clk_register_fixed(dev_id, rate, THIS_MODULE);
> > >    }
> > >      #define v4l2_clk_name_i2c(name, size, adap, client) snprintf(name, size,
> > > \

--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html