Re: [PATCH v4 2/2] V4L: add CCF support to the v4l2_clk API
Hi Mauro,
On Mon, 2 Mar 2015, Mauro Carvalho Chehab wrote:
Em Sun, 1 Feb 2015 12:12:33 +0100 (CET)
Guennadi Liakhovetski g.liakhovet...@gmx.de escreveu:
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
Acked-by: Laurent Pinchart laurent.pinch...@ideasonboard.com
---
v4: sizeof(*clk) :)
drivers/media/v4l2-core/v4l2-clk.c | 48
+++---
include/media/v4l2-clk.h | 2 ++
2 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-clk.c
b/drivers/media/v4l2-core/v4l2-clk.c
index 3ff0b00..9f8cb20 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
@@ -37,6 +38,21 @@ static struct v4l2_clk *v4l2_clk_find(const char *dev_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);
+
+ if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
+ return ERR_PTR(-EPROBE_DEFER);
Why not do just:
return ccf_clk;
I would prefer that shorter form too, but the function returns struct
v4l2_clk * and ccf_clk is struct clk *
Thanks
Guennadi
--
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
Re: [PATCH v4 2/2] V4L: add CCF support to the v4l2_clk API
Em Mon, 02 Mar 2015 20:52:41 +
laurent.pinch...@ideasonboard.com escreveu:
Hi Mauro,
On Mon Mar 02 2015 18:55:23 GMT+0200 (EET), Mauro Carvalho Chehab wrote:
Em Sun, 1 Feb 2015 12:12:33 +0100 (CET)
Guennadi Liakhovetski g.liakhovet...@gmx.de escreveu:
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
Acked-by: Laurent Pinchart laurent.pinch...@ideasonboard.com
---
v4: sizeof(*clk) :)
drivers/media/v4l2-core/v4l2-clk.c | 48
+++---
include/media/v4l2-clk.h | 2 ++
2 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-clk.c
b/drivers/media/v4l2-core/v4l2-clk.c
index 3ff0b00..9f8cb20 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
@@ -37,6 +38,21 @@ static struct v4l2_clk *v4l2_clk_find(const char
*dev_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);
+
+ if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
+ return ERR_PTR(-EPROBE_DEFER);
Why not do just:
return ccf_clk;
I find the explicit error slightly more readable, but that's a matter of
taste.
Well, return(ccf_clk) will likely produce a smaller instruction code
than return (long).
+
+ if (!IS_ERR_OR_NULL(ccf_clk)) {
+ clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+ if (!clk) {
+ clk_put(ccf_clk);
+ return ERR_PTR(-ENOMEM);
+ }
+ clk-clk = ccf_clk;
+
+ return clk;
+ }
The error condition here looks a little weird to me. I mean, if the
CCF clock returns an error, shouldn't it fail instead of silently
run some logic to find another clock source? Isn't it risky on getting
a wrong value?
The idea is that, in the long term, everything should use CCF directly.
However, we have clock providers on platforms where CCF isn't avalaible. V4L2
clock has been introduced as a single API usable by V4L2 clock users
allowing them to retrieve and use clocks regardless of whether the provider
uses CCF or not. Internally it first tries CCF, and then falls back to the
non-CCF implementation in case of failure.
Yeah, I got that the non-CCF is a fallback code, to be used on
platforms that CCF isn't available.
However, the above code doesn't seem to look if CCF is available
or not. Instead, it assumes that *all* error codes, or even NULL,
means that CCF isn't available.
Shouldn't it be, instead, either waiting for NULL or for some
specific error code, in order to:
- return the error code, if CCF is available but getting
the clock failed;
- run the backward-compat code when CCF is not available.
Regards,
Mauro
--
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
Re: [PATCH v4 2/2] V4L: add CCF support to the v4l2_clk API
Em Wed, 04 Mar 2015 00:56:18 +0200
Laurent Pinchart laurent.pinch...@ideasonboard.com escreveu:
Hi Mauro,
On Tuesday 03 March 2015 13:40:50 Mauro Carvalho Chehab wrote:
Em Mon, 02 Mar 2015 20:52:41 + Laurent Pinchart escreveu:
On Mon Mar 02 2015 18:55:23 GMT+0200 (EET), Mauro Carvalho Chehab wrote:
Em Sun, 1 Feb 2015 12:12:33 +0100 (CET) Guennadi Liakhovetski escreveu:
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
Acked-by: Laurent Pinchart laurent.pinch...@ideasonboard.com
---
v4: sizeof(*clk) :)
drivers/media/v4l2-core/v4l2-clk.c | 48 ++---
include/media/v4l2-clk.h | 2 ++
2 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-clk.c
b/drivers/media/v4l2-core/v4l2-clk.c index 3ff0b00..9f8cb20 100644
--- a/drivers/media/v4l2-core/v4l2-clk.c
+++ b/drivers/media/v4l2-core/v4l2-clk.c
[snip]
@@ -37,6 +38,21 @@ static struct v4l2_clk *v4l2_clk_find(const char
*dev_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);
+
+ if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
+ return ERR_PTR(-EPROBE_DEFER);
Why not do just:
return ccf_clk;
I find the explicit error slightly more readable, but that's a matter of
taste.
Well, return(ccf_clk) will likely produce a smaller instruction code
than return (long).
Not if the compiler is smart :-)
+
+ if (!IS_ERR_OR_NULL(ccf_clk)) {
+ clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+ if (!clk) {
+ clk_put(ccf_clk);
+ return ERR_PTR(-ENOMEM);
+ }
+ clk-clk = ccf_clk;
+
+ return clk;
+ }
The error condition here looks a little weird to me. I mean, if the
CCF clock returns an error, shouldn't it fail instead of silently
run some logic to find another clock source? Isn't it risky on getting
a wrong value?
The idea is that, in the long term, everything should use CCF directly.
However, we have clock providers on platforms where CCF isn't avalaible.
V4L2 clock has been introduced as a single API usable by V4L2 clock
users allowing them to retrieve and use clocks regardless of whether the
provider uses CCF or not. Internally it first tries CCF, and then falls
back to the non-CCF implementation in case of failure.
Yeah, I got that the non-CCF is a fallback code, to be used on
platforms that CCF isn't available.
However, the above code doesn't seem to look if CCF is available
or not. Instead, it assumes that *all* error codes, or even NULL,
means that CCF isn't available.
Shouldn't it be, instead, either waiting for NULL or for some
specific error code, in order to:
- return the error code, if CCF is available but getting
the clock failed;
- run the backward-compat code when CCF is not available.
Isn't that pretty much what the code is doing ? If we get a -EPROBE_DEFER
error from CCF meaning that the clock is known but not registered yet we
return it. Otherwise, if the clock is unknown to CCF, or if CCF is disabled,
we fall back.
I didn't check the CCF code, but couldn't it return error codes like
ENOMEM? What are all the error codes it can return ATM? What, among
them, can happen when CCF is available?
Also, as the CCF code can be changed, if the intent behavior is to only
allow EPROBE_DEFER or NULL, if the there is support for CCF, then you
need to have an explicit comment there to avoid that any newer patches
to add different error codes.
IMHO, it seems a way better to define a single error code to be
returned when the platform doesn't support CCF (like -ENOTSUPP),
and calling the fallback code only in this case. Something like:
if (PTR_ERR(ccf_clk) != -ENOTSUPP)
return ccf_clk;
/* CCF is not supported. Fall back to the old way */
k = kzalloc(sizeof(*clk), GFP_KERNEL);
if (!clk) {
clk_put(ccf_clk);
return ERR_PTR(-ENOMEM);
}
clk-clk = ccf_clk;
return clk;
Regards,
Mauro
--
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
Re: [PATCH v4 2/2] V4L: add CCF support to the v4l2_clk API
Hi Mauro,
On Tuesday 03 March 2015 20:21:29 Mauro Carvalho Chehab wrote:
Em Wed, 04 Mar 2015 00:56:18 +0200 Laurent Pinchart escreveu:
On Tuesday 03 March 2015 13:40:50 Mauro Carvalho Chehab wrote:
Em Mon, 02 Mar 2015 20:52:41 + Laurent Pinchart escreveu:
On Mon Mar 02 2015 18:55:23 GMT+0200 (EET), Mauro Carvalho Chehab wrote:
Em Sun, 1 Feb 2015 12:12:33 +0100 (CET) Guennadi Liakhovetski escreveu:
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
Acked-by: Laurent Pinchart laurent.pinch...@ideasonboard.com
---
v4: sizeof(*clk) :)
drivers/media/v4l2-core/v4l2-clk.c | 48 ---
include/media/v4l2-clk.h | 2 ++
2 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-clk.c
b/drivers/media/v4l2-core/v4l2-clk.c index 3ff0b00..9f8cb20 100644
--- a/drivers/media/v4l2-core/v4l2-clk.c
+++ b/drivers/media/v4l2-core/v4l2-clk.c
[snip]
@@ -37,6 +38,21 @@ static struct v4l2_clk *v4l2_clk_find(const char
*dev_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);
+
+ if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
+ return ERR_PTR(-EPROBE_DEFER);
Why not do just:
return ccf_clk;
I find the explicit error slightly more readable, but that's a matter
of taste.
Well, return(ccf_clk) will likely produce a smaller instruction code
than return (long).
Not if the compiler is smart :-)
+
+ if (!IS_ERR_OR_NULL(ccf_clk)) {
+ clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+ if (!clk) {
+ clk_put(ccf_clk);
+ return ERR_PTR(-ENOMEM);
+ }
+ clk-clk = ccf_clk;
+
+ return clk;
+ }
The error condition here looks a little weird to me. I mean, if the
CCF clock returns an error, shouldn't it fail instead of silently
run some logic to find another clock source? Isn't it risky on
getting a wrong value?
The idea is that, in the long term, everything should use CCF
directly. However, we have clock providers on platforms where CCF
isn't avalaible. V4L2 clock has been introduced as a single API
usable by V4L2 clock users allowing them to retrieve and use clocks
regardless of whether the provider uses CCF or not. Internally it
first tries CCF, and then falls back to the non-CCF implementation in
case of failure.
Yeah, I got that the non-CCF is a fallback code, to be used on
platforms that CCF isn't available.
However, the above code doesn't seem to look if CCF is available
or not. Instead, it assumes that *all* error codes, or even NULL,
means that CCF isn't available.
Shouldn't it be, instead, either waiting for NULL or for some
specific error code, in order to:
- return the error code, if CCF is available but getting
the clock failed;
- run the backward-compat code when CCF is not available.
Isn't that pretty much what the code is doing ? If we get a -EPROBE_DEFER
error from CCF meaning that the clock is known but not registered yet we
return it. Otherwise, if the clock is unknown to CCF, or if CCF is
disabled, we fall back.
I didn't check the CCF code, but couldn't it return error codes like
ENOMEM? What are all the error codes it can return ATM? What, among
them, can happen when CCF is available?
Also, as the CCF code can be changed, if the intent behavior is to only
allow EPROBE_DEFER or NULL, if the there is support for CCF, then you
need to have an explicit comment there to avoid that any newer patches
to add different error codes.
IMHO, it seems a way better to define a single error code to be
returned when the platform doesn't support CCF (like -ENOTSUPP),
But that's not how CCF works :-)
Regardless of that, note that the clk_get() call is part of the Linux clock
API, of which CCF is one implementation. clk_get() is implemented by custom
architecture code on platforms where CCF isn't used.
The idea of this patch is to
- return the platform clock if available (clk_get() returns a non-NULL, non-
error pointer)
- defer probing if the platform clock requests so
- fall back to the internal clocks list
I don't see a need for something else.
and calling the fallback code only in this case. Something like:
if (PTR_ERR(ccf_clk) != -ENOTSUPP)
return ccf_clk;
/* CCF is not supported. Fall back to the old way */
k = kzalloc(sizeof(*clk), GFP_KERNEL);
if (!clk) {
Re: [PATCH v4 2/2] V4L: add CCF support to the v4l2_clk API
Hi Mauro,
On Tuesday 03 March 2015 13:40:50 Mauro Carvalho Chehab wrote:
Em Mon, 02 Mar 2015 20:52:41 + Laurent Pinchart escreveu:
On Mon Mar 02 2015 18:55:23 GMT+0200 (EET), Mauro Carvalho Chehab wrote:
Em Sun, 1 Feb 2015 12:12:33 +0100 (CET) Guennadi Liakhovetski escreveu:
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
Acked-by: Laurent Pinchart laurent.pinch...@ideasonboard.com
---
v4: sizeof(*clk) :)
drivers/media/v4l2-core/v4l2-clk.c | 48 ++---
include/media/v4l2-clk.h | 2 ++
2 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-clk.c
b/drivers/media/v4l2-core/v4l2-clk.c index 3ff0b00..9f8cb20 100644
--- a/drivers/media/v4l2-core/v4l2-clk.c
+++ b/drivers/media/v4l2-core/v4l2-clk.c
[snip]
@@ -37,6 +38,21 @@ static struct v4l2_clk *v4l2_clk_find(const char
*dev_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);
+
+ if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
+ return ERR_PTR(-EPROBE_DEFER);
Why not do just:
return ccf_clk;
I find the explicit error slightly more readable, but that's a matter of
taste.
Well, return(ccf_clk) will likely produce a smaller instruction code
than return (long).
Not if the compiler is smart :-)
+
+ if (!IS_ERR_OR_NULL(ccf_clk)) {
+ clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+ if (!clk) {
+ clk_put(ccf_clk);
+ return ERR_PTR(-ENOMEM);
+ }
+ clk-clk = ccf_clk;
+
+ return clk;
+ }
The error condition here looks a little weird to me. I mean, if the
CCF clock returns an error, shouldn't it fail instead of silently
run some logic to find another clock source? Isn't it risky on getting
a wrong value?
The idea is that, in the long term, everything should use CCF directly.
However, we have clock providers on platforms where CCF isn't avalaible.
V4L2 clock has been introduced as a single API usable by V4L2 clock
users allowing them to retrieve and use clocks regardless of whether the
provider uses CCF or not. Internally it first tries CCF, and then falls
back to the non-CCF implementation in case of failure.
Yeah, I got that the non-CCF is a fallback code, to be used on
platforms that CCF isn't available.
However, the above code doesn't seem to look if CCF is available
or not. Instead, it assumes that *all* error codes, or even NULL,
means that CCF isn't available.
Shouldn't it be, instead, either waiting for NULL or for some
specific error code, in order to:
- return the error code, if CCF is available but getting
the clock failed;
- run the backward-compat code when CCF is not available.
Isn't that pretty much what the code is doing ? If we get a -EPROBE_DEFER
error from CCF meaning that the clock is known but not registered yet we
return it. Otherwise, if the clock is unknown to CCF, or if CCF is disabled,
we fall back.
--
Regards,
Laurent Pinchart
--
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
Re: [PATCH v4 2/2] V4L: add CCF support to the v4l2_clk API
Hi Mauro,
On Mon Mar 02 2015 18:55:23 GMT+0200 (EET), Mauro Carvalho Chehab wrote:
Em Sun, 1 Feb 2015 12:12:33 +0100 (CET)
Guennadi Liakhovetski g.liakhovet...@gmx.de escreveu:
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
Acked-by: Laurent Pinchart laurent.pinch...@ideasonboard.com
---
v4: sizeof(*clk) :)
drivers/media/v4l2-core/v4l2-clk.c | 48
+++---
include/media/v4l2-clk.h | 2 ++
2 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-clk.c
b/drivers/media/v4l2-core/v4l2-clk.c
index 3ff0b00..9f8cb20 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
@@ -37,6 +38,21 @@ static struct v4l2_clk *v4l2_clk_find(const char *dev_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);
+
+ if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
+ return ERR_PTR(-EPROBE_DEFER);
Why not do just:
return ccf_clk;
I find the explicit error slightly more readable, but that's a matter of taste.
+
+ if (!IS_ERR_OR_NULL(ccf_clk)) {
+ clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+ if (!clk) {
+ clk_put(ccf_clk);
+ return ERR_PTR(-ENOMEM);
+ }
+ clk-clk = ccf_clk;
+
+ return clk;
+ }
The error condition here looks a little weird to me. I mean, if the
CCF clock returns an error, shouldn't it fail instead of silently
run some logic to find another clock source? Isn't it risky on getting
a wrong value?
The idea is that, in the long term, everything should use CCF directly.
However, we have clock providers on platforms where CCF isn't avalaible. V4L2
clock has been introduced as a single API usable by V4L2 clock users allowing
them to retrieve and use clocks regardless of whether the provider uses CCF or
not. Internally it first tries CCF, and then falls back to the non-CCF
implementation in case of failure.
If the above code is right, please add a comment there explaining
why it is safe to discard the CCF clock error.
mutex_lock(clk_lock);
clk = v4l2_clk_find(dev_name(dev));
@@ -56,6 +72,12 @@ 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)
@@ -93,8 +115,12 @@ 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_prepare_enable(clk-clk);
+
+ ret = v4l2_clk_lock_driver(clk);
if (ret 0)
return ret;
@@ -120,6 +146,9 @@ void v4l2_clk_disable(struct v4l2_clk *clk)
{
int enable;
+ if (clk-clk)
+ return clk_disable_unprepare(clk-clk);
+
mutex_lock(clk-lock);
enable = --clk-enable;
@@ -137,8 +166,12 @@ 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;
@@ -157,7 +190,16 @@ 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 928045f..3ef6e3d 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;
@@ -29,6 +30,7 @@ struct v4l2_clk {
int enable;
struct mutex lock; /* Protect the enable count */
atomic_t use_count;
+ struct clk *clk;
void *priv;
Re: [PATCH v4 2/2] V4L: add CCF support to the v4l2_clk API
Em Sun, 1 Feb 2015 12:12:33 +0100 (CET)
Guennadi Liakhovetski g.liakhovet...@gmx.de escreveu:
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
Acked-by: Laurent Pinchart laurent.pinch...@ideasonboard.com
---
v4: sizeof(*clk) :)
drivers/media/v4l2-core/v4l2-clk.c | 48
+++---
include/media/v4l2-clk.h | 2 ++
2 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-clk.c
b/drivers/media/v4l2-core/v4l2-clk.c
index 3ff0b00..9f8cb20 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
@@ -37,6 +38,21 @@ static struct v4l2_clk *v4l2_clk_find(const char *dev_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);
+
+ if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
+ return ERR_PTR(-EPROBE_DEFER);
Why not do just:
return ccf_clk;
+
+ if (!IS_ERR_OR_NULL(ccf_clk)) {
+ clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+ if (!clk) {
+ clk_put(ccf_clk);
+ return ERR_PTR(-ENOMEM);
+ }
+ clk-clk = ccf_clk;
+
+ return clk;
+ }
The error condition here looks a little weird to me. I mean, if the
CCF clock returns an error, shouldn't it fail instead of silently
run some logic to find another clock source? Isn't it risky on getting
a wrong value?
If the above code is right, please add a comment there explaining
why it is safe to discard the CCF clock error.
mutex_lock(clk_lock);
clk = v4l2_clk_find(dev_name(dev));
@@ -56,6 +72,12 @@ 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)
@@ -93,8 +115,12 @@ 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_prepare_enable(clk-clk);
+
+ ret = v4l2_clk_lock_driver(clk);
if (ret 0)
return ret;
@@ -120,6 +146,9 @@ void v4l2_clk_disable(struct v4l2_clk *clk)
{
int enable;
+ if (clk-clk)
+ return clk_disable_unprepare(clk-clk);
+
mutex_lock(clk-lock);
enable = --clk-enable;
@@ -137,8 +166,12 @@ 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;
@@ -157,7 +190,16 @@ 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 928045f..3ef6e3d 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;
@@ -29,6 +30,7 @@ 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
Re: [PATCH v4 2/2] V4L: add CCF support to the v4l2_clk API
Hi, Guennadi
On 2/1/2015 7:12 PM, Guennadi Liakhovetski wrote:
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
Acked-by: Laurent Pinchart laurent.pinch...@ideasonboard.com
Thanks for the patch.
Tested-by: Josh Wu josh...@atmel.com
Best Regards,
Josh Wu
---
v4: sizeof(*clk) :)
drivers/media/v4l2-core/v4l2-clk.c | 48 +++---
include/media/v4l2-clk.h | 2 ++
2 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-clk.c
b/drivers/media/v4l2-core/v4l2-clk.c
index 3ff0b00..9f8cb20 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
@@ -37,6 +38,21 @@ static struct v4l2_clk *v4l2_clk_find(const char *dev_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);
+
+ if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
+ return ERR_PTR(-EPROBE_DEFER);
+
+ if (!IS_ERR_OR_NULL(ccf_clk)) {
+ clk = kzalloc(sizeof(*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));
@@ -56,6 +72,12 @@ 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)
@@ -93,8 +115,12 @@ 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_prepare_enable(clk-clk);
+
+ ret = v4l2_clk_lock_driver(clk);
if (ret 0)
return ret;
@@ -120,6 +146,9 @@ void v4l2_clk_disable(struct v4l2_clk *clk)
{
int enable;
+ if (clk-clk)
+ return clk_disable_unprepare(clk-clk);
+
mutex_lock(clk-lock);
enable = --clk-enable;
@@ -137,8 +166,12 @@ 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;
@@ -157,7 +190,16 @@ 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 928045f..3ef6e3d 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;
@@ -29,6 +30,7 @@ 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
[PATCH v4 2/2] V4L: 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
Acked-by: Laurent Pinchart laurent.pinch...@ideasonboard.com
---
v4: sizeof(*clk) :)
drivers/media/v4l2-core/v4l2-clk.c | 48 +++---
include/media/v4l2-clk.h | 2 ++
2 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-clk.c
b/drivers/media/v4l2-core/v4l2-clk.c
index 3ff0b00..9f8cb20 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
@@ -37,6 +38,21 @@ static struct v4l2_clk *v4l2_clk_find(const char *dev_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);
+
+ if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
+ return ERR_PTR(-EPROBE_DEFER);
+
+ if (!IS_ERR_OR_NULL(ccf_clk)) {
+ clk = kzalloc(sizeof(*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));
@@ -56,6 +72,12 @@ 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)
@@ -93,8 +115,12 @@ 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_prepare_enable(clk-clk);
+
+ ret = v4l2_clk_lock_driver(clk);
if (ret 0)
return ret;
@@ -120,6 +146,9 @@ void v4l2_clk_disable(struct v4l2_clk *clk)
{
int enable;
+ if (clk-clk)
+ return clk_disable_unprepare(clk-clk);
+
mutex_lock(clk-lock);
enable = --clk-enable;
@@ -137,8 +166,12 @@ 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;
@@ -157,7 +190,16 @@ 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 928045f..3ef6e3d 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;
@@ -29,6 +30,7 @@ struct v4l2_clk {
int enable;
struct mutex lock; /* Protect the enable count */
atomic_t use_count;
+ struct clk *clk;
void *priv;
};
--
1.9.3
--
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
