RE: [PATCH v4] drm/exynos: prepare FIMD clocks
2013/4/22 Inki Dae 2013/4/22 Rafael J. Wysocki r...@sisk.pl On Monday, April 22, 2013 12:37:36 PM Tomasz Figa wrote: On Monday 22 of April 2013 12:17:39 Sylwester Nawrocki wrote: On 04/22/2013 12:03 PM, Inki Dae wrote: Also looks good to me. But what if power domain was disabled without pm runtime? In this case, you must enable the power domain at machine code or bootloader somewhere. This way would not only need some hard codes to turn the power domain on but also not manage power management fully. This is same as only the use of pm runtime interface(needing some hard codes without pm runtime) so I don't prefer to add clk_enable/disable to fimd probe(). I quite tend to force only the use of pm runtime as possible. So please add the hard codes to machine code or bootloader like you did for power domain if you want to use drm fimd without pm runtime. That's not how the runtime PM, clock subsystems work: 1) When CONFIG_PM_RUNTIME is disabled, all the used hardware must be kept powered on all the time. 2) Common Clock Framework will always gate all clocks that have zero enable_count. Note that CCF support for Exynos is already merged for 3.10 and it will be the only available clock support method for Exynos. AFAIK, drivers must work correctly in both cases, with CONFIG_PM_RUNTIME enabled and disabled. Then is the driver worked correctly if the power domain to this device was disabled at bootloader without CONFIG_PM_RUNTIME and with clk_enable()? I think, in this case, the device wouldn't be worked correctly because the power of the device remains off. So you must enable the power domain somewhere. What is the difference between these two cases? How about making the driver dependant on PM_RUNTIME and making it always use pm_runtime_* API, regardless if the platform actually implements runtime PM or not ? Is there any issue in using the Runtime PM core always, rather than coding any workarounds in drivers when PM_RUNTIME is disabled ? I don't think this is a good idea. This would mean that any user that from some reasons don't want to use PM_RUNTIME, would not be able to use the driver anymore. Rafael, Kevin, do you have any opinion on this? I agree. Drivers should work for CONFIG_PM_RUNTIME unset too and static inline stubs for all runtime PM helpers are available in that case. Hi Rafael, The embedded system, at least Exynos SoC case, has the power domain device and this device could be enabled only by pm runtime interface. So the device couldn't be worked correctly without turning the power domain on only calling clk_enable(). In this case, the power domain must be enabled at machine code or bootloader. And the machine without CONFIG_PM_RUNTIME would assume that their own drivers always are enabled so the devices would be worked correctly. Is there any my missing point? - Power domain: not controlled if !CONFIG_PM_RUNTIME. Thus, we may assume that every power domain is kept ON from boot time if !CONFIG_PM_RUNTIME. If power domain is kept OFF from boot time (machine init code or bootloader) with !CONFIG_PM_RUNTIME, then it's simple a mistake at BSP writer. - Yes, the clock is still controlled while !CONFIG_PM_RUNTIME. My opinion is also to let probe do clk-enables though I don't want it to have #ifdef or clk_enable() in the probe function. Thus, implementing power_on()-like function in the driver and let probe() and runtime_pm_get callback call it seems appropriate to me. (that fimd_active(ctx, true) is power-on to itself, right?) Cheers, MyungJoo -- 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] drm/exynos: prepare FIMD clocks
On Sunday 21 of April 2013 22:36:08 Inki Dae wrote:
2013/4/21 Tomasz Figa tomasz.f...@gmail.com
Hi,
On Monday 08 of April 2013 16:41:54 Viresh Kumar wrote:
On 8 April 2013 16:37, Vikas Sajjan vikas.saj...@linaro.org wrote:
While migrating to common clock framework (CCF), I found that the
FIMD
clocks were pulled down by the CCF.
If CCF finds any clock(s) which has NOT been claimed by any of the
drivers, then such clock(s) are PULLed low by CCF.
Calling clk_prepare() for FIMD clocks fixes the issue.
This patch also replaces clk_disable() with clk_unprepare() during
exit, since clk_prepare() is called in fimd_probe().
I asked you about fixing your commit log too.. It still looks
incorrect
to me.
This patch doesn't have anything to do with CCF pulling clocks down,
but calling clk_prepare() before clk_enable() is must now.. that's
it.. nothing more.
I fully agree.
The message should be something like:
Common Clock Framework introduced the need to prepare clocks before
enabling them, otherwise clk_enable() fails. This patch adds
clk_prepare calls to the driver.
and that's all.
What you are observing as CCF pulling clocks down is the fact that
clk_enable() fails if the clock is not prepared and so the clock is
not
enabled in result.
Another thing is that CCF is not pulling anything down. GPIO pins can
be pulled down (or up or not pulled), but clocks can be masked, gated
or simply disabled - this does not imply their signal level.
Signed-off-by: Vikas Sajjan vikas.saj...@linaro.org
---
Changes since v3:
- added clk_prepare() in fimd_probe() and clk_unprepare()
in
fimd_remove()
as suggested by Viresh Kumar viresh.ku...@linaro.org
Changes since v2:
- moved clk_prepare_enable() and clk_disable_unprepare()
from
fimd_probe() to fimd_clock() as suggested by Inki Dae
inki@samsung.com
Changes since v1:
- added error checking for clk_prepare_enable() and also
replaced
clk_disable() with clk_disable_unprepare() during exit.
---
drivers/gpu/drm/exynos/exynos_drm_fimd.c | 14 --
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
b/drivers/gpu/drm/exynos/exynos_drm_fimd.c index 9537761..aa22370
100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -934,6 +934,16 @@ static int fimd_probe(struct platform_device
*pdev)
return ret;
}
+ ret = clk_prepare(ctx-bus_clk);
+ if (ret 0)
+ return ret;
+
+ ret = clk_prepare(ctx-lcd_clk);
+ if (ret 0) {
+ clk_unprepare(ctx-bus_clk);
+ return ret;
+ }
+
Why not just simply use clk_prepare_enable() instead of all calls to
clk_enable() in the driver?
Same goes for s/clk_disable/clk_disable_unprepare/ .
I agree with you. Using clk_prepare_enable() is more clear. Actually I
had already commented on this. Please see the patch v2. But this way
also looks good to me.
Well, both versions are technically correct and will have the same effect
for Exynos SoC clocks, since only enable/disable ops change hardware
state.
However if we look at general meaning of those generic ops, the clock will
remain prepared for all the time the driver is loaded, even if the device
Right, so I said previous one is more clear. I gonna revert current one
and then merge previous one(v3)
is runtime suspended. Again on Exynos SoCs this won't have any effect, but
I think we should respect general Common Clock Framework semantics anyway.
ctx-vidcon0 = pdata-vidcon0;
ctx-vidcon1 = pdata-vidcon1;
ctx-default_win = pdata-default_win;
@@ -981,8 +991,8 @@ static int fimd_remove(struct platform_device
*pdev)
if (ctx-suspended)
goto out;
- clk_disable(ctx-lcd_clk);
- clk_disable(ctx-bus_clk);
+ clk_unprepare(ctx-lcd_clk);
+ clk_unprepare(ctx-bus_clk);
This looks wrong again.. You still need to call clk_disable() to
make
clk enabled
count zero...
Viresh is right again here.
Ok, you two guys say together this looks wrong so I'd like to take more
checking. I thought that clk-clk_enable is 1 at here and it would be 0
by pm_runtimg_put_sync(). Is there any my missing
Re: [PATCH v4] drm/exynos: prepare FIMD clocks
On Monday 22 of April 2013 10:44:00 Viresh Kumar wrote:
On 21 April 2013 20:13, Tomasz Figa tomasz.f...@gmail.com wrote:
3) after those two changes, all that remains is to fix compliance with
Common Clock Framework, in other words:
s/clk_enable/clk_prepare_enable/
and
s/clk_disable/clk_disable_unprepare/
We don't have to call clk_{un}prepare() everytime for your platform as
you aren't doing anything in it. So just call them once at probe/remove and
call clk_enable/disable everywhere else.
Can you assure that in future SoCs, on which this driver will be used, this
assumption will still hold true or even that in current Exynos driver this
behavior won't be changed?
Best regards,
--
Tomasz Figa
Samsung Poland RD Center
SW Solution Development, Kernel and System Framework
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Re: [PATCH v4] drm/exynos: prepare FIMD clocks
On 04/22/2013 11:56 AM, Tomasz Figa wrote:
On Monday 22 of April 2013 10:44:00 Viresh Kumar wrote:
On 21 April 2013 20:13, Tomasz Figa tomasz.f...@gmail.com wrote:
3) after those two changes, all that remains is to fix compliance with
Common Clock Framework, in other words:
s/clk_enable/clk_prepare_enable/
and
s/clk_disable/clk_disable_unprepare/
We don't have to call clk_{un}prepare() everytime for your platform as
you aren't doing anything in it. So just call them once at probe/remove and
call clk_enable/disable everywhere else.
Yes, I agree with that. Additionally clk_(un)prepare must not be called in
atomic context, so some drivers will have to work like this anyway.
Or the clocks could be prepared/unprepared in the device open/close file op
for instance.
Can you assure that in future SoCs, on which this driver will be used, this
assumption will still hold true or even that in current Exynos driver this
behavior won't be changed?
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Re: [PATCH v4] drm/exynos: prepare FIMD clocks
On 04/22/2013 12:03 PM, Inki Dae wrote: Also looks good to me. But what if power domain was disabled without pm runtime? In this case, you must enable the power domain at machine code or bootloader somewhere. This way would not only need some hard codes to turn the power domain on but also not manage power management fully. This is same as only the use of pm runtime interface(needing some hard codes without pm runtime) so I don't prefer to add clk_enable/disable to fimd probe(). I quite tend to force only the use of pm runtime as possible. So please add the hard codes to machine code or bootloader like you did for power domain if you want to use drm fimd without pm runtime. That's not how the runtime PM, clock subsystems work: 1) When CONFIG_PM_RUNTIME is disabled, all the used hardware must be kept powered on all the time. 2) Common Clock Framework will always gate all clocks that have zero enable_count. Note that CCF support for Exynos is already merged for 3.10 and it will be the only available clock support method for Exynos. AFAIK, drivers must work correctly in both cases, with CONFIG_PM_RUNTIME enabled and disabled. Then is the driver worked correctly if the power domain to this device was disabled at bootloader without CONFIG_PM_RUNTIME and with clk_enable()? I think, in this case, the device wouldn't be worked correctly because the power of the device remains off. So you must enable the power domain somewhere. What is the difference between these two cases? How about making the driver dependant on PM_RUNTIME and making it always use pm_runtime_* API, regardless if the platform actually implements runtime PM or not ? Is there any issue in using the Runtime PM core always, rather than coding any workarounds in drivers when PM_RUNTIME is disabled ? Thanks, Sylwester -- 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] drm/exynos: prepare FIMD clocks
On 22 April 2013 15:26, Tomasz Figa t.f...@samsung.com wrote: Can you assure that in future SoCs, on which this driver will be used, this assumption will still hold true or even that in current Exynos driver this behavior won't be changed? Probably yes.. Registers for enabling/disabling these clocks should always be on AMBA bus and not on SPI/I2C, i.e. on-soc... and so this will hold true. -- 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] drm/exynos: prepare FIMD clocks
On Monday 22 of April 2013 12:17:39 Sylwester Nawrocki wrote: On 04/22/2013 12:03 PM, Inki Dae wrote: Also looks good to me. But what if power domain was disabled without pm runtime? In this case, you must enable the power domain at machine code or bootloader somewhere. This way would not only need some hard codes to turn the power domain on but also not manage power management fully. This is same as only the use of pm runtime interface(needing some hard codes without pm runtime) so I don't prefer to add clk_enable/disable to fimd probe(). I quite tend to force only the use of pm runtime as possible. So please add the hard codes to machine code or bootloader like you did for power domain if you want to use drm fimd without pm runtime. That's not how the runtime PM, clock subsystems work: 1) When CONFIG_PM_RUNTIME is disabled, all the used hardware must be kept powered on all the time. 2) Common Clock Framework will always gate all clocks that have zero enable_count. Note that CCF support for Exynos is already merged for 3.10 and it will be the only available clock support method for Exynos. AFAIK, drivers must work correctly in both cases, with CONFIG_PM_RUNTIME enabled and disabled. Then is the driver worked correctly if the power domain to this device was disabled at bootloader without CONFIG_PM_RUNTIME and with clk_enable()? I think, in this case, the device wouldn't be worked correctly because the power of the device remains off. So you must enable the power domain somewhere. What is the difference between these two cases? How about making the driver dependant on PM_RUNTIME and making it always use pm_runtime_* API, regardless if the platform actually implements runtime PM or not ? Is there any issue in using the Runtime PM core always, rather than coding any workarounds in drivers when PM_RUNTIME is disabled ? I don't think this is a good idea. This would mean that any user that from some reasons don't want to use PM_RUNTIME, would not be able to use the driver anymore. Rafael, Kevin, do you have any opinion on this? Best regards, -- Tomasz Figa Samsung Poland RD Center SW Solution Development, Kernel and System Framework -- 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] drm/exynos: prepare FIMD clocks
On Monday, April 22, 2013 12:37:36 PM Tomasz Figa wrote: On Monday 22 of April 2013 12:17:39 Sylwester Nawrocki wrote: On 04/22/2013 12:03 PM, Inki Dae wrote: Also looks good to me. But what if power domain was disabled without pm runtime? In this case, you must enable the power domain at machine code or bootloader somewhere. This way would not only need some hard codes to turn the power domain on but also not manage power management fully. This is same as only the use of pm runtime interface(needing some hard codes without pm runtime) so I don't prefer to add clk_enable/disable to fimd probe(). I quite tend to force only the use of pm runtime as possible. So please add the hard codes to machine code or bootloader like you did for power domain if you want to use drm fimd without pm runtime. That's not how the runtime PM, clock subsystems work: 1) When CONFIG_PM_RUNTIME is disabled, all the used hardware must be kept powered on all the time. 2) Common Clock Framework will always gate all clocks that have zero enable_count. Note that CCF support for Exynos is already merged for 3.10 and it will be the only available clock support method for Exynos. AFAIK, drivers must work correctly in both cases, with CONFIG_PM_RUNTIME enabled and disabled. Then is the driver worked correctly if the power domain to this device was disabled at bootloader without CONFIG_PM_RUNTIME and with clk_enable()? I think, in this case, the device wouldn't be worked correctly because the power of the device remains off. So you must enable the power domain somewhere. What is the difference between these two cases? How about making the driver dependant on PM_RUNTIME and making it always use pm_runtime_* API, regardless if the platform actually implements runtime PM or not ? Is there any issue in using the Runtime PM core always, rather than coding any workarounds in drivers when PM_RUNTIME is disabled ? I don't think this is a good idea. This would mean that any user that from some reasons don't want to use PM_RUNTIME, would not be able to use the driver anymore. Rafael, Kevin, do you have any opinion on this? I agree. Drivers should work for CONFIG_PM_RUNTIME unset too and static inline stubs for all runtime PM helpers are available in that case. Thanks, Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- 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] drm/exynos: prepare FIMD clocks
On Monday 22 of April 2013 12:05:49 Sylwester Nawrocki wrote:
On 04/22/2013 11:56 AM, Tomasz Figa wrote:
On Monday 22 of April 2013 10:44:00 Viresh Kumar wrote:
On 21 April 2013 20:13, Tomasz Figa tomasz.f...@gmail.com wrote:
3) after those two changes, all that remains is to fix compliance with
Common Clock Framework, in other words:
s/clk_enable/clk_prepare_enable/
and
s/clk_disable/clk_disable_unprepare/
We don't have to call clk_{un}prepare() everytime for your platform as
you aren't doing anything in it. So just call them once at probe/remove
and
call clk_enable/disable everywhere else.
Yes, I agree with that. Additionally clk_(un)prepare must not be called in
atomic context, so some drivers will have to work like this anyway.
Or the clocks could be prepared/unprepared in the device open/close file op
for instance.
Well, I don't think drivers should make any assumptions how particular clk ops
are implemented on particular platform.
Instead, generic semantics of Common Clock Framework should be obeyed, which
AFAIK are:
1) Each clock must be prepared before enabling.
2) clk_prepare() can not be called from atomic contexts.
3) clk_prepare_enable() can be used instead of clk_prepare() + clk_enable()
when the driver does not need to enable the clock from atomic context.
Since the Exynos DRM FIMD driver does not need to do call any clock operations
in atomic contexts, the approach keeping the clock handling as simple as
possible would be to just replace all clk_{enable,disable} with
clk_{prepare_enable,disable_unprepare}, as I suggested.
CCing Mike, the maintainer of Common Clock Framework, since he's the right
person to pass any judgements when it is about clocks.
Best regards,
--
Tomasz Figa
Samsung Poland RD Center
SW Solution Development, Kernel and System Framework
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Re: [PATCH v4] drm/exynos: prepare FIMD clocks
Hi,
On Monday 08 of April 2013 16:41:54 Viresh Kumar wrote:
On 8 April 2013 16:37, Vikas Sajjan vikas.saj...@linaro.org wrote:
While migrating to common clock framework (CCF), I found that the FIMD
clocks were pulled down by the CCF.
If CCF finds any clock(s) which has NOT been claimed by any of the
drivers, then such clock(s) are PULLed low by CCF.
Calling clk_prepare() for FIMD clocks fixes the issue.
This patch also replaces clk_disable() with clk_unprepare() during
exit, since clk_prepare() is called in fimd_probe().
I asked you about fixing your commit log too.. It still looks incorrect
to me.
This patch doesn't have anything to do with CCF pulling clocks down, but
calling clk_prepare() before clk_enable() is must now.. that's it..
nothing more.
I fully agree.
The message should be something like:
Common Clock Framework introduced the need to prepare clocks before
enabling them, otherwise clk_enable() fails. This patch adds clk_prepare
calls to the driver.
and that's all.
What you are observing as CCF pulling clocks down is the fact that
clk_enable() fails if the clock is not prepared and so the clock is not
enabled in result.
Another thing is that CCF is not pulling anything down. GPIO pins can be
pulled down (or up or not pulled), but clocks can be masked, gated or
simply disabled - this does not imply their signal level.
Signed-off-by: Vikas Sajjan vikas.saj...@linaro.org
---
Changes since v3:
- added clk_prepare() in fimd_probe() and clk_unprepare() in
fimd_remove()
as suggested by Viresh Kumar viresh.ku...@linaro.org
Changes since v2:
- moved clk_prepare_enable() and clk_disable_unprepare() from
fimd_probe() to fimd_clock() as suggested by Inki Dae
inki@samsung.com
Changes since v1:
- added error checking for clk_prepare_enable() and also
replaced
clk_disable() with clk_disable_unprepare() during exit.
---
drivers/gpu/drm/exynos/exynos_drm_fimd.c | 14 --
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
b/drivers/gpu/drm/exynos/exynos_drm_fimd.c index 9537761..aa22370
100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -934,6 +934,16 @@ static int fimd_probe(struct platform_device
*pdev)
return ret;
}
+ ret = clk_prepare(ctx-bus_clk);
+ if (ret 0)
+ return ret;
+
+ ret = clk_prepare(ctx-lcd_clk);
+ if (ret 0) {
+ clk_unprepare(ctx-bus_clk);
+ return ret;
+ }
+
Why not just simply use clk_prepare_enable() instead of all calls to
clk_enable() in the driver?
Same goes for s/clk_disable/clk_disable_unprepare/ .
ctx-vidcon0 = pdata-vidcon0;
ctx-vidcon1 = pdata-vidcon1;
ctx-default_win = pdata-default_win;
@@ -981,8 +991,8 @@ static int fimd_remove(struct platform_device
*pdev)
if (ctx-suspended)
goto out;
- clk_disable(ctx-lcd_clk);
- clk_disable(ctx-bus_clk);
+ clk_unprepare(ctx-lcd_clk);
+ clk_unprepare(ctx-bus_clk);
This looks wrong again.. You still need to call clk_disable() to make
clk enabled
count zero...
Viresh is right again here.
Best regards,
Tomasz
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Re: [PATCH v4] drm/exynos: prepare FIMD clocks
Hi Inki,
On Sunday 21 of April 2013 22:36:08 Inki Dae wrote:
2013/4/21 Tomasz Figa tomasz.f...@gmail.com
Hi,
On Monday 08 of April 2013 16:41:54 Viresh Kumar wrote:
On 8 April 2013 16:37, Vikas Sajjan vikas.saj...@linaro.org wrote:
While migrating to common clock framework (CCF), I found that the
FIMD
clocks were pulled down by the CCF.
If CCF finds any clock(s) which has NOT been claimed by any of the
drivers, then such clock(s) are PULLed low by CCF.
Calling clk_prepare() for FIMD clocks fixes the issue.
This patch also replaces clk_disable() with clk_unprepare() during
exit, since clk_prepare() is called in fimd_probe().
I asked you about fixing your commit log too.. It still looks
incorrect
to me.
This patch doesn't have anything to do with CCF pulling clocks down,
but calling clk_prepare() before clk_enable() is must now.. that's
it.. nothing more.
I fully agree.
The message should be something like:
Common Clock Framework introduced the need to prepare clocks before
enabling them, otherwise clk_enable() fails. This patch adds
clk_prepare calls to the driver.
and that's all.
What you are observing as CCF pulling clocks down is the fact that
clk_enable() fails if the clock is not prepared and so the clock is
not
enabled in result.
Another thing is that CCF is not pulling anything down. GPIO pins can
be pulled down (or up or not pulled), but clocks can be masked, gated
or simply disabled - this does not imply their signal level.
Signed-off-by: Vikas Sajjan vikas.saj...@linaro.org
---
Changes since v3:
- added clk_prepare() in fimd_probe() and clk_unprepare()
in
fimd_remove()
as suggested by Viresh Kumar viresh.ku...@linaro.org
Changes since v2:
- moved clk_prepare_enable() and clk_disable_unprepare()
from
fimd_probe() to fimd_clock() as suggested by Inki Dae
inki@samsung.com
Changes since v1:
- added error checking for clk_prepare_enable() and also
replaced
clk_disable() with clk_disable_unprepare() during exit.
---
drivers/gpu/drm/exynos/exynos_drm_fimd.c | 14 --
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
b/drivers/gpu/drm/exynos/exynos_drm_fimd.c index 9537761..aa22370
100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -934,6 +934,16 @@ static int fimd_probe(struct platform_device
*pdev)
return ret;
}
+ ret = clk_prepare(ctx-bus_clk);
+ if (ret 0)
+ return ret;
+
+ ret = clk_prepare(ctx-lcd_clk);
+ if (ret 0) {
+ clk_unprepare(ctx-bus_clk);
+ return ret;
+ }
+
Why not just simply use clk_prepare_enable() instead of all calls to
clk_enable() in the driver?
Same goes for s/clk_disable/clk_disable_unprepare/ .
I agree with you. Using clk_prepare_enable() is more clear. Actually I
had already commented on this. Please see the patch v2. But this way
also looks good to me.
Well, both versions are technically correct and will have the same effect
for Exynos SoC clocks, since only enable/disable ops change hardware
state.
However if we look at general meaning of those generic ops, the clock will
remain prepared for all the time the driver is loaded, even if the device
is runtime suspended. Again on Exynos SoCs this won't have any effect, but
I think we should respect general Common Clock Framework semantics anyway.
ctx-vidcon0 = pdata-vidcon0;
ctx-vidcon1 = pdata-vidcon1;
ctx-default_win = pdata-default_win;
@@ -981,8 +991,8 @@ static int fimd_remove(struct platform_device
*pdev)
if (ctx-suspended)
goto out;
- clk_disable(ctx-lcd_clk);
- clk_disable(ctx-bus_clk);
+ clk_unprepare(ctx-lcd_clk);
+ clk_unprepare(ctx-bus_clk);
This looks wrong again.. You still need to call clk_disable() to
make
clk enabled
count zero...
Viresh is right again here.
Ok, you two guys say together this looks wrong so I'd like to take more
checking. I thought that clk-clk_enable is 1 at here and it would be 0
by pm_runtimg_put_sync(). Is there any my missing point?
You're reasoning is correct, but only assuming that runtime PM is enabled.
When it is disabled, pm_runtime_put_sync() is a no-op.
Well, after digging into the exynos_drm_fimd driver a bit more, it seems
like its power management code needs a serious rework, because I was able
to find more problems:
1) fimd_activate()
Re: [PATCH v4] drm/exynos: prepare FIMD clocks
On 21 April 2013 20:13, Tomasz Figa tomasz.f...@gmail.com wrote:
3) after those two changes, all that remains is to fix compliance with
Common Clock Framework, in other words:
s/clk_enable/clk_prepare_enable/
and
s/clk_disable/clk_disable_unprepare/
We don't have to call clk_{un}prepare() everytime for your platform as
you aren't doing anything in it. So just call them once at probe/remove and
call clk_enable/disable everywhere else.
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[PATCH v4] drm/exynos: prepare FIMD clocks
While migrating to common clock framework (CCF), I found that the FIMD clocks
were pulled down by the CCF.
If CCF finds any clock(s) which has NOT been claimed by any of the
drivers, then such clock(s) are PULLed low by CCF.
Calling clk_prepare() for FIMD clocks fixes the issue.
This patch also replaces clk_disable() with clk_unprepare() during exit, since
clk_prepare() is called in fimd_probe().
Signed-off-by: Vikas Sajjan vikas.saj...@linaro.org
---
Changes since v3:
- added clk_prepare() in fimd_probe() and clk_unprepare() in
fimd_remove()
as suggested by Viresh Kumar viresh.ku...@linaro.org
Changes since v2:
- moved clk_prepare_enable() and clk_disable_unprepare() from
fimd_probe() to fimd_clock() as suggested by Inki Dae
inki@samsung.com
Changes since v1:
- added error checking for clk_prepare_enable() and also replaced
clk_disable() with clk_disable_unprepare() during exit.
---
drivers/gpu/drm/exynos/exynos_drm_fimd.c | 14 --
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
index 9537761..aa22370 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -934,6 +934,16 @@ static int fimd_probe(struct platform_device *pdev)
return ret;
}
+ ret = clk_prepare(ctx-bus_clk);
+ if (ret 0)
+ return ret;
+
+ ret = clk_prepare(ctx-lcd_clk);
+ if (ret 0) {
+ clk_unprepare(ctx-bus_clk);
+ return ret;
+ }
+
ctx-vidcon0 = pdata-vidcon0;
ctx-vidcon1 = pdata-vidcon1;
ctx-default_win = pdata-default_win;
@@ -981,8 +991,8 @@ static int fimd_remove(struct platform_device *pdev)
if (ctx-suspended)
goto out;
- clk_disable(ctx-lcd_clk);
- clk_disable(ctx-bus_clk);
+ clk_unprepare(ctx-lcd_clk);
+ clk_unprepare(ctx-bus_clk);
pm_runtime_set_suspended(dev);
pm_runtime_put_sync(dev);
--
1.7.9.5
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Re: [PATCH v4] drm/exynos: prepare FIMD clocks
On 8 April 2013 16:37, Vikas Sajjan vikas.saj...@linaro.org wrote:
While migrating to common clock framework (CCF), I found that the FIMD clocks
were pulled down by the CCF.
If CCF finds any clock(s) which has NOT been claimed by any of the
drivers, then such clock(s) are PULLed low by CCF.
Calling clk_prepare() for FIMD clocks fixes the issue.
This patch also replaces clk_disable() with clk_unprepare() during exit, since
clk_prepare() is called in fimd_probe().
I asked you about fixing your commit log too.. It still looks incorrect to me.
This patch doesn't have anything to do with CCF pulling clocks down, but
calling clk_prepare() before clk_enable() is must now.. that's it..
nothing more.
Signed-off-by: Vikas Sajjan vikas.saj...@linaro.org
---
Changes since v3:
- added clk_prepare() in fimd_probe() and clk_unprepare() in
fimd_remove()
as suggested by Viresh Kumar viresh.ku...@linaro.org
Changes since v2:
- moved clk_prepare_enable() and clk_disable_unprepare() from
fimd_probe() to fimd_clock() as suggested by Inki Dae
inki@samsung.com
Changes since v1:
- added error checking for clk_prepare_enable() and also replaced
clk_disable() with clk_disable_unprepare() during exit.
---
drivers/gpu/drm/exynos/exynos_drm_fimd.c | 14 --
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
index 9537761..aa22370 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -934,6 +934,16 @@ static int fimd_probe(struct platform_device *pdev)
return ret;
}
+ ret = clk_prepare(ctx-bus_clk);
+ if (ret 0)
+ return ret;
+
+ ret = clk_prepare(ctx-lcd_clk);
+ if (ret 0) {
+ clk_unprepare(ctx-bus_clk);
+ return ret;
+ }
+
ctx-vidcon0 = pdata-vidcon0;
ctx-vidcon1 = pdata-vidcon1;
ctx-default_win = pdata-default_win;
@@ -981,8 +991,8 @@ static int fimd_remove(struct platform_device *pdev)
if (ctx-suspended)
goto out;
- clk_disable(ctx-lcd_clk);
- clk_disable(ctx-bus_clk);
+ clk_unprepare(ctx-lcd_clk);
+ clk_unprepare(ctx-bus_clk);
This looks wrong again.. You still need to call clk_disable() to make
clk enabled
count zero...
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