diff mbox series

[21/31] soc/tegra: Remove the call to devm_pm_opp_set_clkname()

Message ID 1e88b248352afe03cd3bf0e887b1f2be86b5afb5.1653564321.git.viresh.kumar@linaro.org
State New
Headers show
Series OPP: Add new configuration interface: dev_pm_opp_set_config() | expand

Commit Message

Viresh Kumar May 26, 2022, 11:42 a.m. UTC
The OPP core already performs devm_pm_opp_set_clkname() with name as
NULL, the callers shouldn't be doing the same unless they have a
different clock name to add here.

Drop the call.

Cc: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/soc/tegra/common.c | 6 ------
 1 file changed, 6 deletions(-)

Comments

Jon Hunter June 23, 2022, 9:15 p.m. UTC | #1
Hi Viresh,

On 26/05/2022 12:42, Viresh Kumar wrote:
> The OPP core already performs devm_pm_opp_set_clkname() with name as
> NULL, the callers shouldn't be doing the same unless they have a
> different clock name to add here.
> 
> Drop the call.
> 
> Cc: Dmitry Osipenko <digetx@gmail.com>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>   drivers/soc/tegra/common.c | 6 ------
>   1 file changed, 6 deletions(-)
> 
> diff --git a/drivers/soc/tegra/common.c b/drivers/soc/tegra/common.c
> index 32c346b72635..49a5360f4507 100644
> --- a/drivers/soc/tegra/common.c
> +++ b/drivers/soc/tegra/common.c
> @@ -108,12 +108,6 @@ int devm_tegra_core_dev_init_opp_table(struct device *dev,
>   	u32 hw_version;
>   	int err;
>   
> -	err = devm_pm_opp_set_clkname(dev, NULL);
> -	if (err) {
> -		dev_err(dev, "failed to set OPP clk: %d\n", err);
> -		return err;
> -	}
> -
>   	/* Tegra114+ doesn't support OPP yet */
>   	if (!of_machine_is_compatible("nvidia,tegra20") &&
>   	    !of_machine_is_compatible("nvidia,tegra30"))


This appears to be breaking a few Tegra drivers. For example, on Tegra210
Jetson TX1 I am seeing the following and the eMMC is no longer working ...

[    0.526729] sdhci-tegra 700b0600.mmc: dev_pm_opp_set_rate: device's opp table doesn't exist
[    0.526733] sdhci-tegra 700b0600.mmc: failed to set clk rate to 400000Hz: -19
[    0.528830] sdhci-tegra 700b0600.mmc: dev_pm_opp_set_rate: device's opp table doesn't exist
[    0.528833] sdhci-tegra 700b0600.mmc: failed to set clk rate to 400000Hz: -19

I have seen another instance of this on Jetson Xavier NX ...

[   12.301336] tegra-pwm 32d0000.pwm: dev_pm_opp_set_rate: device's opp table doesn't exist
[   12.301350] tegra-pwm 32d0000.pwm: Failed to set max frequency: -19

Bisect is point to this commit and so something is not working as
expected.

Cheers
Jon
Viresh Kumar June 24, 2022, 12:28 a.m. UTC | #2
On 23-06-22, 22:15, Jon Hunter wrote:
> On 26/05/2022 12:42, Viresh Kumar wrote:
> > diff --git a/drivers/soc/tegra/common.c b/drivers/soc/tegra/common.c
> > index 32c346b72635..49a5360f4507 100644
> > --- a/drivers/soc/tegra/common.c
> > +++ b/drivers/soc/tegra/common.c
> > @@ -108,12 +108,6 @@ int devm_tegra_core_dev_init_opp_table(struct device *dev,
> >   	u32 hw_version;
> >   	int err;
> > -	err = devm_pm_opp_set_clkname(dev, NULL);
> > -	if (err) {
> > -		dev_err(dev, "failed to set OPP clk: %d\n", err);
> > -		return err;
> > -	}
> > -
> >   	/* Tegra114+ doesn't support OPP yet */
> >   	if (!of_machine_is_compatible("nvidia,tegra20") &&
> >   	    !of_machine_is_compatible("nvidia,tegra30"))
> 
> 
> This appears to be breaking a few Tegra drivers. For example, on Tegra210
> Jetson TX1 I am seeing the following and the eMMC is no longer working ...
> 
> [    0.526729] sdhci-tegra 700b0600.mmc: dev_pm_opp_set_rate: device's opp table doesn't exist
> [    0.526733] sdhci-tegra 700b0600.mmc: failed to set clk rate to 400000Hz: -19
> [    0.528830] sdhci-tegra 700b0600.mmc: dev_pm_opp_set_rate: device's opp table doesn't exist
> [    0.528833] sdhci-tegra 700b0600.mmc: failed to set clk rate to 400000Hz: -19
> 
> I have seen another instance of this on Jetson Xavier NX ...
> 
> [   12.301336] tegra-pwm 32d0000.pwm: dev_pm_opp_set_rate: device's opp table doesn't exist
> [   12.301350] tegra-pwm 32d0000.pwm: Failed to set max frequency: -19
> 
> Bisect is point to this commit and so something is not working as
> expected.

Thanks again Jon.

This is what happens when the special code doesn't have a comment
attached with it. Neither the reviewer, nor the author remember why
the special piece was required :)

I had to go through the whole sequence, along with DT to understand
what might have broken this stuff :)

I will drop this patch and add this comment in its place:

diff --git a/drivers/soc/tegra/common.c b/drivers/soc/tegra/common.c
index 32c346b72635..9f3fdeb1a11c 100644
--- a/drivers/soc/tegra/common.c
+++ b/drivers/soc/tegra/common.c
@@ -108,6 +108,13 @@ int devm_tegra_core_dev_init_opp_table(struct device *dev,
        u32 hw_version;
        int err;

+       /*
+        * For some devices we don't have any OPP table in the DT, and in order
+        * to use the same code path for all the devices, we create a dummy OPP
+        * table for them via this call. The dummy OPP table is only capable of
+        * doing clk_set_rate() on invocation of dev_pm_opp_set_rate() and
+        * doesn't provide any other functionality.
+        */
        err = devm_pm_opp_set_clkname(dev, NULL);
        if (err) {
                dev_err(dev, "failed to set OPP clk: %d\n", err);


Though there will still be a problem here with my changes, we don't
accept NULL clkname anymore for the set-clkname API. And tegra does
this to pick the first clock available in DT (at index 0) I think.
Other drivers (mostly qcom) who need such dummy OPP table, provide a
real clock name instead. Will it be possible to pass that here somehow
?
Viresh Kumar June 24, 2022, 12:59 a.m. UTC | #3
On 24-06-22, 05:58, Viresh Kumar wrote:
> Though there will still be a problem here with my changes, we don't
> accept NULL clkname anymore for the set-clkname API. And tegra does
> this to pick the first clock available in DT (at index 0) I think.
> Other drivers (mostly qcom) who need such dummy OPP table, provide a
> real clock name instead. Will it be possible to pass that here somehow
> ?

Jon,

Okay, I was able to handle it without making any further updates to
the OPP core. Nothing else required from your side on this.

I have pushed the updates (to this patch and 22/31) to opp/linux-next
branch. You can try it now and it should just work. I have only build
tested it though.

Thanks.
Jon Hunter June 24, 2022, 10:32 a.m. UTC | #4
On 24/06/2022 01:59, Viresh Kumar wrote:
> On 24-06-22, 05:58, Viresh Kumar wrote:
>> Though there will still be a problem here with my changes, we don't
>> accept NULL clkname anymore for the set-clkname API. And tegra does
>> this to pick the first clock available in DT (at index 0) I think.
>> Other drivers (mostly qcom) who need such dummy OPP table, provide a
>> real clock name instead. Will it be possible to pass that here somehow
>> ?
> 
> Jon,
> 
> Okay, I was able to handle it without making any further updates to
> the OPP core. Nothing else required from your side on this.
> 
> I have pushed the updates (to this patch and 22/31) to opp/linux-next
> branch. You can try it now and it should just work. I have only build
> tested it though.


Thanks. I have reverted the previous versions of 21 and 22, and pulled 
in the latest and these are working.

Cheers
Jon
diff mbox series

Patch

diff --git a/drivers/soc/tegra/common.c b/drivers/soc/tegra/common.c
index 32c346b72635..49a5360f4507 100644
--- a/drivers/soc/tegra/common.c
+++ b/drivers/soc/tegra/common.c
@@ -108,12 +108,6 @@  int devm_tegra_core_dev_init_opp_table(struct device *dev,
 	u32 hw_version;
 	int err;
 
-	err = devm_pm_opp_set_clkname(dev, NULL);
-	if (err) {
-		dev_err(dev, "failed to set OPP clk: %d\n", err);
-		return err;
-	}
-
 	/* Tegra114+ doesn't support OPP yet */
 	if (!of_machine_is_compatible("nvidia,tegra20") &&
 	    !of_machine_is_compatible("nvidia,tegra30"))