linux-kernel - Re: [PATCH 08/25] media: atmel: properly get pm

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Date:   Thu, 10 Jun 2021 11:38:27 +0200
From:   Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
To:     <Eugen.Hristev@...rochip.com>
Cc:     <Jonathan.Cameron@...wei.com>, <linuxarm@...wei.com>,
        <mauro.chehab@...wei.com>, <alexandre.belloni@...tlin.com>,
        <Ludovic.Desroches@...rochip.com>, <mchehab@...nel.org>,
        <Nicolas.Ferre@...rochip.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <linux-media@...r.kernel.org>,
        <Claudiu.Beznea@...rochip.com>
Subject: Re: [PATCH 08/25] media: atmel: properly get pm_runtime

Em Thu, 10 Jun 2021 09:04:07 +0000
<Eugen.Hristev@...rochip.com> escreveu:

> >> diff --git a/drivers/media/platform/atmel/atmel-isc-base.c b/drivers/media/platform/atmel/atmel-isc-base.c
> >> index fe3ec8d0eaee..ce8e1351fa53 100644
> >> --- a/drivers/media/platform/atmel/atmel-isc-base.c
> >> +++ b/drivers/media/platform/atmel/atmel-isc-base.c
> >> @@ -294,9 +294,13 @@ static int isc_wait_clk_stable(struct clk_hw *hw)
> >>   static int isc_clk_prepare(struct clk_hw *hw)
> >>   {
> >>        struct isc_clk *isc_clk = to_isc_clk(hw);
> >> +     int ret;
> >>
> >> -     if (isc_clk->id == ISC_ISPCK)
> >> -             pm_runtime_get_sync(isc_clk->dev);
> >> +     if (isc_clk->id == ISC_ISPCK) {
> >> +             ret = pm_runtime_resume_and_get(isc_clk->dev);
> >> +             if (ret < 0)
> >> +                     return ret;
> >> +     }  
> 
> Hi Mauro,
> 
> With this patch, the ISC is broken on latest media tree. It looks like 
> pm_runtime_resume_and_get for the ISC_ISPCK clock returns -ENOACCESS and 
> thus, the probe of the driver fails:
> 
> atmel-sama5d2-isc f0008000.isc: failed to enable ispck: -13
> atmel-sama5d2-isc: probe of f0008000.isc failed with error -13
> 
> 
> Could you point out how I could fix this ? Maybe the isc_clk->dev is not 
> properly handled/initialized in some other part of the code ?

Looking at RPM implementation:

	static int rpm_resume(struct device *dev, int rpmflags)
	{
...
        if (dev->power.runtime_error)
                retval = -EINVAL;
        else if (dev->power.disable_depth == 1 && dev->power.is_suspended
            && dev->power.runtime_status == RPM_ACTIVE)
                retval = 1;
        else if (dev->power.disable_depth > 0)
                retval = -EACCES;
...

It sounds that RPM is disabled for this clock. Did you call
pm_runtime_enable() before calling isc_clk_prepare()?

Thanks,
Mauro