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Subject: Re: [PATCH v6 51/52] PM / devfreq: tegra30: Support interconnect and
 OPPs from device-tree
To:     cwchoi00@gmail.com
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Georgi Djakov <georgi.djakov@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Peter De Schrijver <pdeschrijver@nvidia.com>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        Mikko Perttunen <cyndis@kapsi.fi>,
        Viresh Kumar <vireshk@kernel.org>,
        Peter Geis <pgwipeout@gmail.com>,
        Nicolas Chauvet <kwizart@gmail.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        linux-tegra@vger.kernel.org,
        Linux PM list <linux-pm@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        devicetree <devicetree@vger.kernel.org>
References: <20201025221735.3062-1-digetx@gmail.com>
 <20201025221735.3062-52-digetx@gmail.com>
 <CAGTfZH2rBaWKox9nKM=_Wz8k65FLt1R7D8xSOUxe7xAJ1A00hA@mail.gmail.com>
From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <961863f7-933d-d455-cd5d-99bab898ee75@gmail.com>
Date:   Sun, 1 Nov 2020 18:24:11 +0300
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01.11.2020 17:44, Chanwoo Choi пишет:
> Hi Dmitry,
> 
> On Mon, Oct 26, 2020 at 7:22 AM Dmitry Osipenko <digetx@gmail.com> wrote:
>>
>> This patch moves ACTMON driver away from generating OPP table by itself,
>> transitioning it to use the table which comes from device-tree. This
>> change breaks compatibility with older device-trees in order to bring
>> support for the interconnect framework to the driver. This is a mandatory
>> change which needs to be done in order to implement interconnect-based
>> memory DVFS. Users of legacy device-trees will get a message telling that
>> theirs DT needs to be upgraded. Now ACTMON issues memory bandwidth request
>> using dev_pm_opp_set_bw(), instead of driving EMC clock rate directly.
>>
>> Tested-by: Peter Geis <pgwipeout@gmail.com>
>> Tested-by: Nicolas Chauvet <kwizart@gmail.com>
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>>  drivers/devfreq/tegra30-devfreq.c | 91 ++++++++++++++++---------------
>>  1 file changed, 48 insertions(+), 43 deletions(-)
>>
>> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
>> index 3f732ab53573..1b0b91a71886 100644
>> --- a/drivers/devfreq/tegra30-devfreq.c
>> +++ b/drivers/devfreq/tegra30-devfreq.c
>> @@ -19,6 +19,8 @@
>>  #include <linux/reset.h>
>>  #include <linux/workqueue.h>
>>
>> +#include <soc/tegra/fuse.h>
>> +
> 
> This patch touches the OPP. Is it related to this change?

Yes, this is needed for the dev_pm_opp_set_supported_hw().

>>  #include "governor.h"
>>
>>  #define ACTMON_GLB_STATUS                                      0x0
>> @@ -155,6 +157,7 @@ struct tegra_devfreq_device {
>>
>>  struct tegra_devfreq {
>>         struct devfreq          *devfreq;
>> +       struct opp_table        *opp_table;
>>
>>         struct reset_control    *reset;
>>         struct clk              *clock;
>> @@ -612,34 +615,19 @@ static void tegra_actmon_stop(struct tegra_devfreq *tegra)
>>  static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
>>                                 u32 flags)
>>  {
>> -       struct tegra_devfreq *tegra = dev_get_drvdata(dev);
>> -       struct devfreq *devfreq = tegra->devfreq;
>>         struct dev_pm_opp *opp;
>> -       unsigned long rate;
>> -       int err;
>> +       int ret;
>>
>>         opp = devfreq_recommended_opp(dev, freq, flags);
>>         if (IS_ERR(opp)) {
>> -               dev_err(dev, "Failed to find opp for %lu Hz\n", *freq);
>> +               dev_err(dev, "failed to find opp for %lu Hz\n", *freq);
> 
> You used the 'Failed to' format in almost every error case.
> Don't need to change it.
> (snip)

Good catch, thanks.