Message-ID: <3ea6b48f-af3f-51db-8d7b-1292a68ae74e@canonical.com>
Date:   Mon, 17 May 2021 07:43:56 -0400
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
To:     Dmitry Osipenko <digetx@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Paul Fertser <fercerpav@...il.com>,
        Matt Merhar <mattmerhar@...tonmail.com>,
        Peter Geis <pgwipeout@...il.com>,
        Nicolas Chauvet <kwizart@...il.com>,
        Viresh Kumar <vireshk@...nel.org>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/1] soc/tegra: Add
 devm_tegra_core_dev_init_opp_table()

On 16/05/2021 16:51, Dmitry Osipenko wrote:
> Add common helper which initializes OPP table for Tegra SoC core devices.
> 
> Tested-by: Peter Geis <pgwipeout@...il.com> # Ouya T30
> Tested-by: Paul Fertser <fercerpav@...il.com> # PAZ00 T20
> Tested-by: Nicolas Chauvet <kwizart@...il.com> # PAZ00 T20 and TK1 T124
> Tested-by: Matt Merhar <mattmerhar@...tonmail.com> # Ouya T30
> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
> ---
>  drivers/soc/tegra/common.c | 112 +++++++++++++++++++++++++++++++++++++
>  include/soc/tegra/common.h |  30 ++++++++++
>  2 files changed, 142 insertions(+)
> 
> diff --git a/drivers/soc/tegra/common.c b/drivers/soc/tegra/common.c
> index 3dc54f59cafe..c3fd2facfc2d 100644
> --- a/drivers/soc/tegra/common.c
> +++ b/drivers/soc/tegra/common.c
> @@ -3,9 +3,16 @@
>   * Copyright (C) 2014 NVIDIA CORPORATION.  All rights reserved.
>   */
>  
> +#define dev_fmt(fmt)	"tegra-soc: " fmt
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/export.h>
>  #include <linux/of.h>
> +#include <linux/pm_opp.h>
>  
>  #include <soc/tegra/common.h>
> +#include <soc/tegra/fuse.h>
>  
>  static const struct of_device_id tegra_machine_match[] = {
>  	{ .compatible = "nvidia,tegra20", },
> @@ -31,3 +38,108 @@ bool soc_is_tegra(void)
>  
>  	return match != NULL;
>  }
> +
> +static int tegra_core_dev_init_opp_state(struct device *dev)
> +{
> +	struct dev_pm_opp *opp;
> +	unsigned long rate;
> +	struct clk *clk;
> +	int err;
> +
> +	clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(clk)) {
> +		dev_err(dev, "failed to get clk: %pe\n", clk);
> +		return PTR_ERR(clk);
> +	}
> +
> +	rate = clk_get_rate(clk);
> +	if (!rate) {
> +		dev_err(dev, "failed to get clk rate\n");
> +		return -EINVAL;
> +	}
> +
> +	opp = dev_pm_opp_find_freq_ceil(dev, &rate);
> +
> +	if (opp == ERR_PTR(-ERANGE))
> +		opp = dev_pm_opp_find_freq_floor(dev, &rate);
> +
> +	err = PTR_ERR_OR_ZERO(opp);
> +	if (err) {
> +		dev_err(dev, "failed to get OPP for %ld Hz: %d\n",
> +			rate, err);
> +		return err;
> +	}
> +
> +	dev_pm_opp_put(opp);
> +
> +	/* first dummy rate-setting initializes voltage vote */
> +	err = dev_pm_opp_set_rate(dev, rate);
> +	if (err) {
> +		dev_err(dev, "failed to initialize OPP clock: %d\n", err);
> +		return err;
> +	}


The devm_pm_opp_set_clkname will call clk_get(), so here you should drop
the clk reference at the end. Why having it twice?

> +
> +	return 0;
> +}
> +
> +/**
> + * devm_tegra_core_dev_init_opp_table() - initialize OPP table
> + * @dev: device for which OPP table is initialized
> + * @params: pointer to the OPP table configuration
> + *
> + * This function will initialize OPP table and sync OPP state of a Tegra SoC
> + * core device.
> + *
> + * Return: 0 on success or errorno.
> + */
> +int devm_tegra_core_dev_init_opp_table(struct device *dev,
> +				       struct tegra_core_opp_params *params)
> +{
> +	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"))
> +		return -ENODEV;
> +
> +	if (of_machine_is_compatible("nvidia,tegra20"))
> +		hw_version = BIT(tegra_sku_info.soc_process_id);
> +	else
> +		hw_version = BIT(tegra_sku_info.soc_speedo_id);
> +
> +	err = devm_pm_opp_set_supported_hw(dev, &hw_version, 1);
> +	if (err) {
> +		dev_err(dev, "failed to set OPP supported HW: %d\n", err);
> +		return err;
> +	}
> +
> +	/*
> +	 * Older device-trees have an empty OPP table, we will get
> +	 * -ENODEV from devm_pm_opp_of_add_table() in this case.
> +	 */
> +	err = devm_pm_opp_of_add_table(dev);
> +	if (err) {
> +		if (err == -ENODEV)
> +			dev_err_once(dev, "OPP table not found, please update device-tree\n");
> +		else
> +			dev_err(dev, "failed to add OPP table: %d\n", err);
> +
> +		return err;
> +	}
> +
> +	if (params->init_state) {
> +		err = tegra_core_dev_init_opp_state(dev);
> +		if (err)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(devm_tegra_core_dev_init_opp_table);
> diff --git a/include/soc/tegra/common.h b/include/soc/tegra/common.h
> index 98027a76ce3d..e8eab13aa199 100644
> --- a/include/soc/tegra/common.h
> +++ b/include/soc/tegra/common.h
> @@ -6,6 +6,36 @@
>  #ifndef __SOC_TEGRA_COMMON_H__
>  #define __SOC_TEGRA_COMMON_H__
>  
> +#include <linux/errno.h>
> +#include <linux/types.h>
> +
> +struct device;
> +
> +/**
> + * Tegra SoC core device OPP table configuration
> + *
> + * @init_state: pre-initialize OPP state of a device
> + */
> +struct tegra_core_opp_params {
> +	bool init_state;
> +};
> +
> +#ifdef CONFIG_ARCH_TEGRA
>  bool soc_is_tegra(void);
> +int devm_tegra_core_dev_init_opp_table(struct device *dev,
> +				       struct tegra_core_opp_params *params);
> +#else
> +static inline bool soc_is_tegra(void)

This looks unrelated. Please make it a separate patch.

> +{
> +	return false;
> +}
> +
> +static inline int
> +devm_tegra_core_dev_init_opp_table(struct device *dev,
> +				   struct tegra_core_opp_params *params)
> +{
> +	return -ENODEV;
> +}
> +#endif
>  
>  #endif /* __SOC_TEGRA_COMMON_H__ */
> 


Best regards,
Krzysztof

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