linux-kernel - Re: [PATCH v3 09/11] cpufreq: tegra124-cpufreq: extend to support Tegra210

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Date:   Thu, 8 Mar 2018 23:25:04 +0000
From:   Jon Hunter <jonathanh@...dia.com>
To:     Peter De Schrijver <pdeschrijver@...dia.com>,
        <linux-tegra@...r.kernel.org>, <linux-clk@...r.kernel.org>,
        <mturquette@...libre.com>, <sboyd@...eaurora.org>,
        <robh+dt@...nel.org>, <mark.rutland@....com>,
        <devicetree@...r.kernel.org>, <lgirdwood@...il.com>,
        <broonie@...nel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 09/11] cpufreq: tegra124-cpufreq: extend to support
 Tegra210


On 06/02/18 16:34, Peter De Schrijver wrote:
> Tegra210 has a very similar CPU clocking scheme than Tegra124. So add
> support in this driver. Also allow for the case where the CPU voltage is
> controlled directly by the DFLL rather than by a separate regulator object.
> 
> Signed-off-by: Peter De Schrijver <pdeschrijver@...dia.com>
> ---
>  drivers/cpufreq/tegra124-cpufreq.c | 15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
> index 4353025..f8e01a8 100644
> --- a/drivers/cpufreq/tegra124-cpufreq.c
> +++ b/drivers/cpufreq/tegra124-cpufreq.c
> @@ -64,7 +64,8 @@ static void tegra124_cpu_switch_to_pllx(struct tegra124_cpufreq_priv *priv)
>  {
>  	clk_set_parent(priv->cpu_clk, priv->pllp_clk);
>  	clk_disable_unprepare(priv->dfll_clk);
> -	regulator_sync_voltage(priv->vdd_cpu_reg);
> +	if (priv->vdd_cpu_reg)
> +		regulator_sync_voltage(priv->vdd_cpu_reg);
>  	clk_set_parent(priv->cpu_clk, priv->pllx_clk);
>  }
>  
> @@ -89,10 +90,10 @@ static int tegra124_cpufreq_probe(struct platform_device *pdev)
>  		return -ENODEV;
>  
>  	priv->vdd_cpu_reg = regulator_get(cpu_dev, "vdd-cpu");
> -	if (IS_ERR(priv->vdd_cpu_reg)) {
> -		ret = PTR_ERR(priv->vdd_cpu_reg);
> -		goto out_put_np;
> -	}
> +	if (IS_ERR(priv->vdd_cpu_reg) != -EPROBE_DEFER)
> +		priv->vdd_cpu_reg = NULL;
> +	else
> +		return -EPROBE_DEFER;

I am still not sure that we should rely on the fact that the regulator
is not present in DT to imply that we do not need it. I think that we
should be checking if we are using I2C mode here.

Cheers
Jon

-- 
nvpublic