diff mbox

[v3,1/2] drivers/base: permit base components to omit the bind/unbind ops

Message ID 9b3c3c2c982f31b026fd1516a2b608026d55b1e9.1391792986.git.moinejf@free.fr (mailing list archive)
State New, archived
Headers show

Commit Message

Jean-Francois Moine Feb. 7, 2014, 3:55 p.m. UTC
Some simple components don't need to do any specific action on
bind to / unbind from a master component.

This patch permits such components to omit the bind/unbind
operations.

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
---
 drivers/base/component.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Comments

Thierry Reding Feb. 10, 2014, 12:53 p.m. UTC | #1
On Fri, Feb 07, 2014 at 04:55:00PM +0100, Jean-Francois Moine wrote:
> Some simple components don't need to do any specific action on
> bind to / unbind from a master component.
> 
> This patch permits such components to omit the bind/unbind
> operations.
> 
> Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
> ---
>  drivers/base/component.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/base/component.c b/drivers/base/component.c
> index c53efe6..0a39d7a 100644
> --- a/drivers/base/component.c
> +++ b/drivers/base/component.c
> @@ -225,7 +225,8 @@ static void component_unbind(struct component *component,
>  {
>  	WARN_ON(!component->bound);
>  
> -	component->ops->unbind(component->dev, master->dev, data);
> +	if (component->ops)
> +		component->ops->unbind(component->dev, master->dev, data);

This doesn't actually do what the commit message says. This makes
component->ops optional, not component->ops->unbind().

A more correct check would be:

	if (component->ops && component->ops->unbind)

>  	component->bound = false;
>  
>  	/* Release all resources claimed in the binding of this component */
> @@ -274,7 +275,11 @@ static int component_bind(struct component *component, struct master *master,
>  	dev_dbg(master->dev, "binding %s (ops %ps)\n",
>  		dev_name(component->dev), component->ops);
>  
> -	ret = component->ops->bind(component->dev, master->dev, data);
> +	if (component->ops)
> +		ret = component->ops->bind(component->dev, master->dev, data);

Same here.

Thierry
Russell King - ARM Linux Feb. 10, 2014, 1:12 p.m. UTC | #2
On Mon, Feb 10, 2014 at 01:53:08PM +0100, Thierry Reding wrote:
> On Fri, Feb 07, 2014 at 04:55:00PM +0100, Jean-Francois Moine wrote:
> > Some simple components don't need to do any specific action on
> > bind to / unbind from a master component.
> > 
> > This patch permits such components to omit the bind/unbind
> > operations.
> > 
> > Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
> > ---
> >  drivers/base/component.c | 9 +++++++--
> >  1 file changed, 7 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/base/component.c b/drivers/base/component.c
> > index c53efe6..0a39d7a 100644
> > --- a/drivers/base/component.c
> > +++ b/drivers/base/component.c
> > @@ -225,7 +225,8 @@ static void component_unbind(struct component *component,
> >  {
> >  	WARN_ON(!component->bound);
> >  
> > -	component->ops->unbind(component->dev, master->dev, data);
> > +	if (component->ops)
> > +		component->ops->unbind(component->dev, master->dev, data);
> 
> This doesn't actually do what the commit message says. This makes
> component->ops optional, not component->ops->unbind().
> 
> A more correct check would be:
> 
> 	if (component->ops && component->ops->unbind)
> 
> >  	component->bound = false;
> >  
> >  	/* Release all resources claimed in the binding of this component */
> > @@ -274,7 +275,11 @@ static int component_bind(struct component *component, struct master *master,
> >  	dev_dbg(master->dev, "binding %s (ops %ps)\n",
> >  		dev_name(component->dev), component->ops);
> >  
> > -	ret = component->ops->bind(component->dev, master->dev, data);
> > +	if (component->ops)
> > +		ret = component->ops->bind(component->dev, master->dev, data);
> 
> Same here.

I've NAK'd these patches already - I believe they're based on a
mis-understanding of how this should be used.  I believe Jean-Francois
has only looked at the core, rather than looking at the imx-drm example
it was posted with in an attempt to understand it.

Omitting the component bind operations is absurd because it makes the
component code completely pointless, since there is then no way to
control the sequencing of driver initialisation - something which is
one of the primary reasons for this code existing in the first place.
Jean-Francois Moine Feb. 10, 2014, 2:35 p.m. UTC | #3
On Mon, 10 Feb 2014 13:12:33 +0000
Russell King - ARM Linux <linux@arm.linux.org.uk> wrote:

> I've NAK'd these patches already - I believe they're based on a
> mis-understanding of how this should be used.  I believe Jean-Francois
> has only looked at the core, rather than looking at the imx-drm example
> it was posted with in an attempt to understand it.
> 
> Omitting the component bind operations is absurd because it makes the
> component code completely pointless, since there is then no way to
> control the sequencing of driver initialisation - something which is
> one of the primary reasons for this code existing in the first place.

I perfectly looked at your example and I use it now in my system.

You did not see what could be done with your component code. For
example, since november, I have not yet the clock probe_defer in the
mainline (http://www.spinics.net/lists/arm-kernel/msg306072.html), so,
there are 3 solutions:

- hope the patch will be some day in the mainline and, today, reboot
  when the system does not start correctly,

- insert a delay in the tda998x and kirkwood probe sequences (delay
  long enough to be sure the si5351 is started, or loop),

- use your component work.

In the last case, it is easy:

- the si5351 driver calls component_add (with empty ops: it has no
  interest in the bind/unbind functions) when it is fully started (i.e.
  registered - that was the subject of my patch),

- in the DRM driver, look for the si5351 as a clock in the DT (drm ->
  encoder -> clock), and add it to the awaited components (CRTCs,
  encoders..),

- in the audio subsystem, look for the si5351 as an external clock in
  the DT (simple-card -> CPU DAI -> clock) and add it to the awaited
  components (CPU and CODEC DAIs - yes, the S/PDIF CODEC should also be
  a component with no bin/unbind ops).

Then, when the si5351 is registered, both master components video and
audio can safely run.
Russell King - ARM Linux Feb. 10, 2014, 3:14 p.m. UTC | #4
On Mon, Feb 10, 2014 at 03:35:51PM +0100, Jean-Francois Moine wrote:
> On Mon, 10 Feb 2014 13:12:33 +0000
> Russell King - ARM Linux <linux@arm.linux.org.uk> wrote:
> 
> > I've NAK'd these patches already - I believe they're based on a
> > mis-understanding of how this should be used.  I believe Jean-Francois
> > has only looked at the core, rather than looking at the imx-drm example
> > it was posted with in an attempt to understand it.
> > 
> > Omitting the component bind operations is absurd because it makes the
> > component code completely pointless, since there is then no way to
> > control the sequencing of driver initialisation - something which is
> > one of the primary reasons for this code existing in the first place.
> 
> I perfectly looked at your example and I use it now in my system.
> 
> You did not see what could be done with your component code. For
> example, since november, I have not yet the clock probe_defer in the
> mainline (http://www.spinics.net/lists/arm-kernel/msg306072.html), so,
> there are 3 solutions:
> 
> - hope the patch will be some day in the mainline and, today, reboot
>   when the system does not start correctly,
> 
> - insert a delay in the tda998x and kirkwood probe sequences (delay
>   long enough to be sure the si5351 is started, or loop),
> 
> - use your component work.
> 
> In the last case, it is easy:
> 
> - the si5351 driver calls component_add (with empty ops: it has no
>   interest in the bind/unbind functions) when it is fully started (i.e.
>   registered - that was the subject of my patch),

There is only one word for this:
Ewwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww.

Definitely not.

The component stuff is there to sort out the subsystems which expect a
"card" but in DT we supply a set of components.  It's not there to sort
out dependencies between different subsystems.

I've no idea why your patch to add the deferred probing hasn't been acked
by Mike yet, but that needs to happen before I take it.  Or, split it up
in two so I can take the clkdev part and Mike can take the CCF part.
diff mbox

Patch

diff --git a/drivers/base/component.c b/drivers/base/component.c
index c53efe6..0a39d7a 100644
--- a/drivers/base/component.c
+++ b/drivers/base/component.c
@@ -225,7 +225,8 @@  static void component_unbind(struct component *component,
 {
 	WARN_ON(!component->bound);
 
-	component->ops->unbind(component->dev, master->dev, data);
+	if (component->ops)
+		component->ops->unbind(component->dev, master->dev, data);
 	component->bound = false;
 
 	/* Release all resources claimed in the binding of this component */
@@ -274,7 +275,11 @@  static int component_bind(struct component *component, struct master *master,
 	dev_dbg(master->dev, "binding %s (ops %ps)\n",
 		dev_name(component->dev), component->ops);
 
-	ret = component->ops->bind(component->dev, master->dev, data);
+	if (component->ops)
+		ret = component->ops->bind(component->dev, master->dev, data);
+	else
+		ret = 0;
+
 	if (!ret) {
 		component->bound = true;