[PATCH] clk: don't call __of_clk_get_by_name() unnecessarily from clk_get()

[PATCH] clk: don't call __of_clk_get_by_name() unnecessarily from clk_get()

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

The way this function is implemented caused some confusion when
converting the TI DaVinci platform to using the common clock framework.

Current kernel supports booting DaVinci boards both in device tree as
well as legacy, board-file mode. In the latter, we always end up
calling clk_get_sys() as of_node is NULL and __of_clk_get_by_name()
returns -ENOENT.

It was not obvious at first glance how clk_get(dev, NULL) will work in
board-file mode since we always call __of_clk_get_by_name(). Let's make
it clearer by checking if of_node is NULL and skipping right to
clk_get_sys().

Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: David Lechner <david@lechnology.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/clk/clkdev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 7513411140b6..f394e8964909 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -199,7 +199,7 @@ struct clk *clk_get(struct device *dev, const char *con_id)
 	const char *dev_id = dev ? dev_name(dev) : NULL;
 	struct clk *clk;
 
-	if (dev) {
+	if (dev && dev->of_node) {
 		clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
 		if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
 			return clk;
-- 
2.16.1

[PATCH] clk: don't call __of_clk_get_by_name() unnecessarily from clk_get()

[David Lechner]

On 02/12/2018 08:24 AM, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> 
> The way this function is implemented caused some confusion when
> converting the TI DaVinci platform to using the common clock framework.
> 
> Current kernel supports booting DaVinci boards both in device tree as
> well as legacy, board-file mode. In the latter, we always end up
> calling clk_get_sys() as of_node is NULL and __of_clk_get_by_name()
> returns -ENOENT.
> 
> It was not obvious at first glance how clk_get(dev, NULL) will work in
> board-file mode since we always call __of_clk_get_by_name(). Let's make
> it clearer by checking if of_node is NULL and skipping right to
> clk_get_sys().
> 
> Cc: Sekhar Nori <nsekhar@ti.com>
> Cc: Kevin Hilman <khilman@baylibre.com>
> Cc: David Lechner <david@lechnology.com>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>   drivers/clk/clkdev.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
> index 7513411140b6..f394e8964909 100644
> --- a/drivers/clk/clkdev.c
> +++ b/drivers/clk/clkdev.c
> @@ -199,7 +199,7 @@ struct clk *clk_get(struct device *dev, const char *con_id)
>   	const char *dev_id = dev ? dev_name(dev) : NULL;
>   	struct clk *clk;
>   
> -	if (dev) {
> +	if (dev && dev->of_node) {
>   		clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
>   		if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
>   			return clk;
> 

Shouldn't you be sending this to the linux-clk mailing list and cc'ing
the clock maintainers?

FWIW, it seems pretty clear to me that if we are using a board file
then we should expect clk_get_sys() to be called because there is
no device tree.

[PATCH] clk: don't call __of_clk_get_by_name() unnecessarily from clk_get()

[Russell King - ARM Linux]

On Mon, Feb 12, 2018 at 02:51:57PM -0600, David Lechner wrote:
> On 02/12/2018 08:24 AM, Bartosz Golaszewski wrote:
> >From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> >
> >The way this function is implemented caused some confusion when
> >converting the TI DaVinci platform to using the common clock framework.
> >
> >Current kernel supports booting DaVinci boards both in device tree as
> >well as legacy, board-file mode. In the latter, we always end up
> >calling clk_get_sys() as of_node is NULL and __of_clk_get_by_name()
> >returns -ENOENT.
> >
> >It was not obvious at first glance how clk_get(dev, NULL) will work in
> >board-file mode since we always call __of_clk_get_by_name(). Let's make
> >it clearer by checking if of_node is NULL and skipping right to
> >clk_get_sys().
> >
> >Cc: Sekhar Nori <nsekhar@ti.com>
> >Cc: Kevin Hilman <khilman@baylibre.com>
> >Cc: David Lechner <david@lechnology.com>
> >Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> >---
> >  drivers/clk/clkdev.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> >diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
> >index 7513411140b6..f394e8964909 100644
> >--- a/drivers/clk/clkdev.c
> >+++ b/drivers/clk/clkdev.c
> >@@ -199,7 +199,7 @@ struct clk *clk_get(struct device *dev, const char *con_id)
> >  	const char *dev_id = dev ? dev_name(dev) : NULL;
> >  	struct clk *clk;
> >-	if (dev) {
> >+	if (dev && dev->of_node) {
> >  		clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
> >  		if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
> >  			return clk;
> >
> 
> Shouldn't you be sending this to the linux-clk mailing list and cc'ing
> the clock maintainers?

No, I'm the maintainer for clkdev, as per MAINTAINERS.

> FWIW, it seems pretty clear to me that if we are using a board file
> then we should expect clk_get_sys() to be called because there is
> no device tree.

clk_get() pre-dates DT, and using it has no bearing on whether DT is
in use or not.  The above change looks correct to me - if the
struct device is not a DT device, then we shouldn't be trying to look
up the clock in DT.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up
According to speedtest.net: 8.21Mbps down 510kbps up

[PATCH] clk: don't call __of_clk_get_by_name() unnecessarily from clk_get()

[David Lechner]

On 02/12/2018 03:00 PM, Russell King - ARM Linux wrote:
> On Mon, Feb 12, 2018 at 02:51:57PM -0600, David Lechner wrote:
>> On 02/12/2018 08:24 AM, Bartosz Golaszewski wrote:
>>> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>>>
>>> The way this function is implemented caused some confusion when
>>> converting the TI DaVinci platform to using the common clock framework.
>>>
>>> Current kernel supports booting DaVinci boards both in device tree as
>>> well as legacy, board-file mode. In the latter, we always end up
>>> calling clk_get_sys() as of_node is NULL and __of_clk_get_by_name()
>>> returns -ENOENT.
>>>
>>> It was not obvious at first glance how clk_get(dev, NULL) will work in
>>> board-file mode since we always call __of_clk_get_by_name(). Let's make
>>> it clearer by checking if of_node is NULL and skipping right to
>>> clk_get_sys().
>>>
>>> Cc: Sekhar Nori <nsekhar@ti.com>
>>> Cc: Kevin Hilman <khilman@baylibre.com>
>>> Cc: David Lechner <david@lechnology.com>
>>> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>>> ---
>>>   drivers/clk/clkdev.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
>>> index 7513411140b6..f394e8964909 100644
>>> --- a/drivers/clk/clkdev.c
>>> +++ b/drivers/clk/clkdev.c
>>> @@ -199,7 +199,7 @@ struct clk *clk_get(struct device *dev, const char *con_id)
>>>   	const char *dev_id = dev ? dev_name(dev) : NULL;
>>>   	struct clk *clk;
>>> -	if (dev) {
>>> +	if (dev && dev->of_node) {
>>>   		clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
>>>   		if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
>>>   			return clk;
>>>
>>
>> Shouldn't you be sending this to the linux-clk mailing list and cc'ing
>> the clock maintainers?
> 
> No, I'm the maintainer for clkdev, as per MAINTAINERS.

Oops, I guess I should have looked before I said something.

> 
>> FWIW, it seems pretty clear to me that if we are using a board file
>> then we should expect clk_get_sys() to be called because there is
>> no device tree.
> 
> clk_get() pre-dates DT, and using it has no bearing on whether DT is
> in use or not.  The above change looks correct to me - if the
> struct device is not a DT device, then we shouldn't be trying to look
> up the clock in DT.
> 

Looks fine to me too.

[PATCH] clk: don't call __of_clk_get_by_name() unnecessarily from clk_get()

[Bartosz Golaszewski]

2018-02-12 22:00 GMT+01:00 Russell King - ARM Linux <linux@armlinux.org.uk>:
> On Mon, Feb 12, 2018 at 02:51:57PM -0600, David Lechner wrote:
>> On 02/12/2018 08:24 AM, Bartosz Golaszewski wrote:
>> >From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>> >
>> >The way this function is implemented caused some confusion when
>> >converting the TI DaVinci platform to using the common clock framework.
>> >
>> >Current kernel supports booting DaVinci boards both in device tree as
>> >well as legacy, board-file mode. In the latter, we always end up
>> >calling clk_get_sys() as of_node is NULL and __of_clk_get_by_name()
>> >returns -ENOENT.
>> >
>> >It was not obvious at first glance how clk_get(dev, NULL) will work in
>> >board-file mode since we always call __of_clk_get_by_name(). Let's make
>> >it clearer by checking if of_node is NULL and skipping right to
>> >clk_get_sys().
>> >
>> >Cc: Sekhar Nori <nsekhar@ti.com>
>> >Cc: Kevin Hilman <khilman@baylibre.com>
>> >Cc: David Lechner <david@lechnology.com>
>> >Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>> >---
>> >  drivers/clk/clkdev.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> >diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
>> >index 7513411140b6..f394e8964909 100644
>> >--- a/drivers/clk/clkdev.c
>> >+++ b/drivers/clk/clkdev.c
>> >@@ -199,7 +199,7 @@ struct clk *clk_get(struct device *dev, const char *con_id)
>> >     const char *dev_id = dev ? dev_name(dev) : NULL;
>> >     struct clk *clk;
>> >-    if (dev) {
>> >+    if (dev && dev->of_node) {
>> >             clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
>> >             if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
>> >                     return clk;
>> >
>>
>> Shouldn't you be sending this to the linux-clk mailing list and cc'ing
>> the clock maintainers?
>
> No, I'm the maintainer for clkdev, as per MAINTAINERS.
>
>> FWIW, it seems pretty clear to me that if we are using a board file
>> then we should expect clk_get_sys() to be called because there is
>> no device tree.
>
> clk_get() pre-dates DT, and using it has no bearing on whether DT is
> in use or not.  The above change looks correct to me - if the
> struct device is not a DT device, then we shouldn't be trying to look
> up the clock in DT.
>
> --
> RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
> FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up
> According to speedtest.net: 8.21Mbps down 510kbps up

Hi Russell,

can you pick this patch up for 4.17?

Thanks in advance,
Bartosz