Re: [PATCH v13 02/35] soc/tegra: Add devm_tegra_core_dev_init_opp_table_common()

[Ulf Hansson]

On Mon, 27 Sept 2021 at 00:42, Dmitry Osipenko <digetx@xxxxxxxxx> wrote:
>
> Only couple drivers need to get the -ENODEV error code and majority of
> drivers need to explicitly initialize the performance state. Add new
> common helper which sets up OPP table for these drivers.
>
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> ---
>  include/soc/tegra/common.h | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/include/soc/tegra/common.h b/include/soc/tegra/common.h
> index af41ad80ec21..5b4a042f60fb 100644
> --- a/include/soc/tegra/common.h
> +++ b/include/soc/tegra/common.h
> @@ -39,4 +39,28 @@ devm_tegra_core_dev_init_opp_table(struct device *dev,
>  }
>  #endif
>
> +/*
> + * This function should be invoked with the enabled runtime PM of the device
> + * in order to initialize performance state properly. Most of Tegra devices
> + * are assumed to be suspended at a probe time and GENPD require RPM to be
> + * enabled to set up the rpm-resume state, otherwise device is active and
> + * performance state is applied immediately. Note that it will initialize
> + * OPP bandwidth if it's wired in a device-tree for this device, which is
> + * undesirable for a suspended device.
> + */
> +static inline int
> +devm_tegra_core_dev_init_opp_table_common(struct device *dev)
> +{
> +       struct tegra_core_opp_params opp_params = {};
> +       int err;
> +
> +       opp_params.init_state = true;
> +
> +       err = devm_tegra_core_dev_init_opp_table(dev, &opp_params);
> +       if (err != -ENODEV)
> +               return err;
> +
> +       return 0;
> +}

Just want to share a few thoughts around these functions.

So, I assume it's fine to call
devm_tegra_core_dev_init_opp_table_common() or
devm_tegra_core_dev_init_opp_table() from consumer drivers during
->probe(), as long as those drivers are tegra specific, which I assume
all are in the series!?

My point is, a cross SoC consumer driver that needs to initiate OPP
tables can get rather messy, if it would need to make one specific
function call per SoC.

That said, I hope we can tackle this as a separate/future problem, so
the series can get merged as is.

> +
>  #endif /* __SOC_TEGRA_COMMON_H__ */
> --
> 2.32.0
>

Kind regards
Uffe