linux-kernel - Re: [PATCH v2 1/4] cpufreq: mediatek: add mt8183 cpufreq support

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Date:   Sat, 30 Mar 2019 17:06:58 -0700
From:   Nicolas Boichat <drinkcat@...omium.org>
To:     "Andrew-sh.Cheng" <andrew-sh.cheng@...iatek.com>
Cc:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        devicetree@...r.kernel.org,
        srv_heupstream <srv_heupstream@...iatek.com>,
        linux-pm@...r.kernel.org, lkml <linux-kernel@...r.kernel.org>,
        Fan Chen <fan.chen@...iatek.com>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2 1/4] cpufreq: mediatek: add mt8183 cpufreq support

On Thu, Mar 28, 2019 at 11:46 PM Andrew-sh.Cheng
<andrew-sh.cheng@...iatek.com> wrote:
>
> For new mediatek chip mt8183,
> cci and little cluster share the same buck,
> so need to modify the attribute of regulator from exclusive to optional
>
> Intermediate clock is not always enabled by ccf in different projects,
> so cpufreq should always enable it by itself.

One comment, otherwise the changes look good. However, I feel that
this patch should be split in 3:
 1. Change to regulator_get_optional
 2. Enable inter_clk
 3. Add support for 8183

> Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng@...iatek.com>
> ---
>  drivers/cpufreq/cpufreq-dt-platdev.c |  1 +
>  drivers/cpufreq/mediatek-cpufreq.c   | 12 ++++++++++--
>  2 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq-dt-platdev.c b/drivers/cpufreq/cpufreq-dt-platdev.c
> index 47729a2..53ea52b 100644
> --- a/drivers/cpufreq/cpufreq-dt-platdev.c
> +++ b/drivers/cpufreq/cpufreq-dt-platdev.c
> @@ -117,6 +117,7 @@
>         { .compatible = "mediatek,mt817x", },
>         { .compatible = "mediatek,mt8173", },
>         { .compatible = "mediatek,mt8176", },
> +       { .compatible = "mediatek,mt8183", },
>
>         { .compatible = "nvidia,tegra124", },
>         { .compatible = "nvidia,tegra210", },
> diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> index 48e9829..7cd01d3 100644
> --- a/drivers/cpufreq/mediatek-cpufreq.c
> +++ b/drivers/cpufreq/mediatek-cpufreq.c
> @@ -346,7 +346,7 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
>                 goto out_free_resources;
>         }
>
> -       proc_reg = regulator_get_exclusive(cpu_dev, "proc");
> +       proc_reg = regulator_get_optional(cpu_dev, "proc");
>         if (IS_ERR(proc_reg)) {
>                 if (PTR_ERR(proc_reg) == -EPROBE_DEFER)
>                         pr_warn("proc regulator for cpu%d not ready, retry.\n",
> @@ -376,13 +376,17 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
>                 goto out_free_resources;
>         }
>
> +       ret = clk_prepare_enable(inter_clk);

Should you disable the clock in mtk_cpu_dvfs_info_release?

> +       if (ret)
> +               goto out_free_opp_table;
> +
>         /* Search a safe voltage for intermediate frequency. */
>         rate = clk_get_rate(inter_clk);
>         opp = dev_pm_opp_find_freq_ceil(cpu_dev, &rate);
>         if (IS_ERR(opp)) {
>                 pr_err("failed to get intermediate opp for cpu%d\n", cpu);
>                 ret = PTR_ERR(opp);
> -               goto out_free_opp_table;
> +               goto out_disable_clock;
>         }
>         info->intermediate_voltage = dev_pm_opp_get_voltage(opp);
>         dev_pm_opp_put(opp);
> @@ -401,6 +405,9 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
>
>         return 0;
>
> +out_disable_clock:
> +       clk_disable_unprepare(inter_clk);
> +
>  out_free_opp_table:
>         dev_pm_opp_of_cpumask_remove_table(&info->cpus);
>
> @@ -543,6 +550,7 @@ static int mtk_cpufreq_probe(struct platform_device *pdev)
>         { .compatible = "mediatek,mt817x", },
>         { .compatible = "mediatek,mt8173", },
>         { .compatible = "mediatek,mt8176", },
> +       { .compatible = "mediatek,mt8183", },
>
>         { }
>  };
> --
> 1.8.1.1.dirty
>
>
> _______________________________________________
> Linux-mediatek mailing list
> Linux-mediatek@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-mediatek

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