* [PATCH] dmaengine: dw: support for clockless platforms
@ 2015-01-20 12:57 Heikki Krogerus
2015-01-20 14:18 ` Andy Shevchenko
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Heikki Krogerus @ 2015-01-20 12:57 UTC (permalink / raw)
To: Viresh Kumar, Andy Shevchenko; +Cc: Vinod Koul, linux-kernel, dmaengine
When requesting clock in the platform driver, leaving
chip->clk value as NULL if -ENOENT is returned, and
continue. With other errors returning failure. It makes the
driver usable on platforms that do not provide the clock.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
drivers/dma/dw/platform.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
index 32ea1ac..b183bc0 100644
--- a/drivers/dma/dw/platform.c
+++ b/drivers/dma/dw/platform.c
@@ -180,8 +180,12 @@ static int dw_probe(struct platform_device *pdev)
chip->dev = dev;
chip->clk = devm_clk_get(chip->dev, "hclk");
- if (IS_ERR(chip->clk))
- return PTR_ERR(chip->clk);
+ if (IS_ERR(chip->clk)) {
+ if (PTR_ERR(chip->clk) == -ENOENT)
+ chip->clk = NULL;
+ else
+ return PTR_ERR(chip->clk);
+ }
err = clk_prepare_enable(chip->clk);
if (err)
return err;
--
2.1.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] dmaengine: dw: support for clockless platforms
2015-01-20 12:57 [PATCH] dmaengine: dw: support for clockless platforms Heikki Krogerus
@ 2015-01-20 14:18 ` Andy Shevchenko
2015-02-11 1:20 ` Vinod Koul
2015-02-11 2:10 ` Viresh Kumar
2 siblings, 0 replies; 7+ messages in thread
From: Andy Shevchenko @ 2015-01-20 14:18 UTC (permalink / raw)
To: Heikki Krogerus; +Cc: Viresh Kumar, Vinod Koul, linux-kernel, dmaengine
On Tue, 2015-01-20 at 14:57 +0200, Heikki Krogerus wrote:
> When requesting clock in the platform driver, leaving
> chip->clk value as NULL if -ENOENT is returned, and
> continue. With other errors returning failure. It makes the
> driver usable on platforms that do not provide the clock.
>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> drivers/dma/dw/platform.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
> index 32ea1ac..b183bc0 100644
> --- a/drivers/dma/dw/platform.c
> +++ b/drivers/dma/dw/platform.c
> @@ -180,8 +180,12 @@ static int dw_probe(struct platform_device *pdev)
> chip->dev = dev;
>
> chip->clk = devm_clk_get(chip->dev, "hclk");
> - if (IS_ERR(chip->clk))
> - return PTR_ERR(chip->clk);
> + if (IS_ERR(chip->clk)) {
> + if (PTR_ERR(chip->clk) == -ENOENT)
> + chip->clk = NULL;
> + else
> + return PTR_ERR(chip->clk);
> + }
> err = clk_prepare_enable(chip->clk);
> if (err)
> return err;
--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] dmaengine: dw: support for clockless platforms
2015-01-20 12:57 [PATCH] dmaengine: dw: support for clockless platforms Heikki Krogerus
2015-01-20 14:18 ` Andy Shevchenko
@ 2015-02-11 1:20 ` Vinod Koul
2015-02-11 2:10 ` Viresh Kumar
2 siblings, 0 replies; 7+ messages in thread
From: Vinod Koul @ 2015-02-11 1:20 UTC (permalink / raw)
To: Heikki Krogerus; +Cc: Viresh Kumar, Andy Shevchenko, linux-kernel, dmaengine
On Tue, Jan 20, 2015 at 02:57:57PM +0200, Heikki Krogerus wrote:
> When requesting clock in the platform driver, leaving
> chip->clk value as NULL if -ENOENT is returned, and
> continue. With other errors returning failure. It makes the
> driver usable on platforms that do not provide the clock.
Applied, thanks
--
~Vinod
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] dmaengine: dw: support for clockless platforms
2015-01-20 12:57 [PATCH] dmaengine: dw: support for clockless platforms Heikki Krogerus
2015-01-20 14:18 ` Andy Shevchenko
2015-02-11 1:20 ` Vinod Koul
@ 2015-02-11 2:10 ` Viresh Kumar
2015-02-11 12:02 ` Andy Shevchenko
2 siblings, 1 reply; 7+ messages in thread
From: Viresh Kumar @ 2015-02-11 2:10 UTC (permalink / raw)
To: Heikki Krogerus, Russell King
Cc: Andy Shevchenko, Vinod Koul, linux-kernel, dmaengine
On Tue, Jan 20, 2015 at 8:57 PM, Heikki Krogerus
<heikki.krogerus@linux.intel.com> wrote:
> When requesting clock in the platform driver, leaving
> chip->clk value as NULL if -ENOENT is returned, and
> continue. With other errors returning failure. It makes the
> driver usable on platforms that do not provide the clock.
>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
> drivers/dma/dw/platform.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
> index 32ea1ac..b183bc0 100644
> --- a/drivers/dma/dw/platform.c
> +++ b/drivers/dma/dw/platform.c
> @@ -180,8 +180,12 @@ static int dw_probe(struct platform_device *pdev)
> chip->dev = dev;
>
> chip->clk = devm_clk_get(chip->dev, "hclk");
> - if (IS_ERR(chip->clk))
> - return PTR_ERR(chip->clk);
> + if (IS_ERR(chip->clk)) {
> + if (PTR_ERR(chip->clk) == -ENOENT)
> + chip->clk = NULL;
This is wrong and reasons are mentioned in this thread:
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-March/088437.html
You don't need to set it to NULL, if CONFIG_HAVE_CLK isn't set
the dummy routines would take care of it.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] dmaengine: dw: support for clockless platforms
2015-02-11 2:10 ` Viresh Kumar
@ 2015-02-11 12:02 ` Andy Shevchenko
2015-02-11 12:07 ` Russell King - ARM Linux
0 siblings, 1 reply; 7+ messages in thread
From: Andy Shevchenko @ 2015-02-11 12:02 UTC (permalink / raw)
To: Viresh Kumar
Cc: Heikki Krogerus, Russell King, Vinod Koul, linux-kernel, dmaengine
On Wed, 2015-02-11 at 10:10 +0800, Viresh Kumar wrote:
> On Tue, Jan 20, 2015 at 8:57 PM, Heikki Krogerus
> <heikki.krogerus@linux.intel.com> wrote:
> > When requesting clock in the platform driver, leaving
> > chip->clk value as NULL if -ENOENT is returned, and
> > continue. With other errors returning failure. It makes the
> > driver usable on platforms that do not provide the clock.
> >
> > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > ---
> > drivers/dma/dw/platform.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
> > index 32ea1ac..b183bc0 100644
> > --- a/drivers/dma/dw/platform.c
> > +++ b/drivers/dma/dw/platform.c
> > @@ -180,8 +180,12 @@ static int dw_probe(struct platform_device *pdev)
> > chip->dev = dev;
> >
> > chip->clk = devm_clk_get(chip->dev, "hclk");
> > - if (IS_ERR(chip->clk))
> > - return PTR_ERR(chip->clk);
> > + if (IS_ERR(chip->clk)) {
> > + if (PTR_ERR(chip->clk) == -ENOENT)
> > + chip->clk = NULL;
>
> This is wrong and reasons are mentioned in this thread:
>
> http://lists.infradead.org/pipermail/linux-arm-kernel/2012-March/088437.html
Thanks for the link.
>
> You don't need to set it to NULL, if CONFIG_HAVE_CLK isn't set
> the dummy routines would take care of it.
Yeah, but in our case we have CONFIG_HAVE_CLK=y and no clk is provided
since IP is clockless. What could you suggest to do in such case?
--
Andy Shevchenko <andriy.shevchenko@intel.com>
Intel Finland Oy
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] dmaengine: dw: support for clockless platforms
2015-02-11 12:02 ` Andy Shevchenko
@ 2015-02-11 12:07 ` Russell King - ARM Linux
2015-02-11 12:19 ` Andy Shevchenko
0 siblings, 1 reply; 7+ messages in thread
From: Russell King - ARM Linux @ 2015-02-11 12:07 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Viresh Kumar, Heikki Krogerus, Vinod Koul, linux-kernel, dmaengine
On Wed, Feb 11, 2015 at 02:02:39PM +0200, Andy Shevchenko wrote:
> On Wed, 2015-02-11 at 10:10 +0800, Viresh Kumar wrote:
> > > chip->clk = devm_clk_get(chip->dev, "hclk");
> > > - if (IS_ERR(chip->clk))
> > > - return PTR_ERR(chip->clk);
> > > + if (IS_ERR(chip->clk)) {
> > > + if (PTR_ERR(chip->clk) == -ENOENT)
> > > + chip->clk = NULL;
> >
> > You don't need to set it to NULL, if CONFIG_HAVE_CLK isn't set
> > the dummy routines would take care of it.
>
> Yeah, but in our case we have CONFIG_HAVE_CLK=y and no clk is provided
> since IP is clockless. What could you suggest to do in such case?
chip->clk = devm_clk_get(chip->dev, "hclk");
if (IS_ERR(chip->clk) && PTR_ERR(chip->clk) != -ENOENT)
return PTR_ERR(chip->clk);
You can then test for the presence of a clk via IS_ERR(chip->clk).
I'm just debating whether we should add a clk_is_valid() inline function
to linux/clk.h to avoid these shouting tests, and make it easier for
people test this in a generic manner.
--
FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] dmaengine: dw: support for clockless platforms
2015-02-11 12:07 ` Russell King - ARM Linux
@ 2015-02-11 12:19 ` Andy Shevchenko
0 siblings, 0 replies; 7+ messages in thread
From: Andy Shevchenko @ 2015-02-11 12:19 UTC (permalink / raw)
To: Russell King - ARM Linux
Cc: Viresh Kumar, Heikki Krogerus, Vinod Koul, linux-kernel, dmaengine
On Wed, 2015-02-11 at 12:07 +0000, Russell King - ARM Linux wrote:
> On Wed, Feb 11, 2015 at 02:02:39PM +0200, Andy Shevchenko wrote:
> > On Wed, 2015-02-11 at 10:10 +0800, Viresh Kumar wrote:
> > > > chip->clk = devm_clk_get(chip->dev, "hclk");
> > > > - if (IS_ERR(chip->clk))
> > > > - return PTR_ERR(chip->clk);
> > > > + if (IS_ERR(chip->clk)) {
> > > > + if (PTR_ERR(chip->clk) == -ENOENT)
> > > > + chip->clk = NULL;
> > >
> > > You don't need to set it to NULL, if CONFIG_HAVE_CLK isn't set
> > > the dummy routines would take care of it.
> >
> > Yeah, but in our case we have CONFIG_HAVE_CLK=y and no clk is provided
> > since IP is clockless. What could you suggest to do in such case?
>
> chip->clk = devm_clk_get(chip->dev, "hclk");
> if (IS_ERR(chip->clk) && PTR_ERR(chip->clk) != -ENOENT)
> return PTR_ERR(chip->clk);
>
> You can then test for the presence of a clk via IS_ERR(chip->clk).
>
> I'm just debating whether we should add a clk_is_valid() inline function
> to linux/clk.h to avoid these shouting tests, and make it easier for
> people test this in a generic manner.
I guess clock framework may handle whatever is gotten from clk_get().
In driver much cleaner to use direct calls with exceptions (like you
can't get a valid clock rate from non-existing clock).
So, what about just passing by the error code and doing nothing?
--
Andy Shevchenko <andriy.shevchenko@intel.com>
Intel Finland Oy
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2015-02-11 12:19 UTC | newest]
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2015-01-20 12:57 [PATCH] dmaengine: dw: support for clockless platforms Heikki Krogerus
2015-01-20 14:18 ` Andy Shevchenko
2015-02-11 1:20 ` Vinod Koul
2015-02-11 2:10 ` Viresh Kumar
2015-02-11 12:02 ` Andy Shevchenko
2015-02-11 12:07 ` Russell King - ARM Linux
2015-02-11 12:19 ` Andy Shevchenko
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