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References: <20230704064610.292603-1-xingyu.wu@starfivetech.com> <20230704064610.292603-6-xingyu.wu@starfivetech.com>
In-Reply-To: <20230704064610.292603-6-xingyu.wu@starfivetech.com>
From:   Emil Renner Berthing <emil.renner.berthing@canonical.com>
Date:   Thu, 13 Jul 2023 15:15:32 +0200
Message-ID: <CAJM55Z-OSmQCV6mO+SD4R2eU5gfx9TArSqDy+d-M2aer6bKL_A@mail.gmail.com>
Subject: Re: [RESEND PATCH v6 5/7] clk: starfive: jh7110-sys: Add PLL clocks
 source from DTS
To:     Xingyu Wu <xingyu.wu@starfivetech.com>
Cc:     linux-riscv@lists.infradead.org, devicetree@vger.kernel.org,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Conor Dooley <conor@kernel.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Hal Feng <hal.feng@starfivetech.com>,
        William Qiu <william.qiu@starfivetech.com>,
        linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org
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Precedence: bulk

On Tue, 4 Jul 2023 at 08:49, Xingyu Wu <xingyu.wu@starfivetech.com> wrote:
>
> Modify PLL clocks source to be got from DTS or
> the fixed factor clocks.
>
> Signed-off-by: Xingyu Wu <xingyu.wu@starfivetech.com>
> ---
>  drivers/clk/starfive/Kconfig                  |  1 +
>  .../clk/starfive/clk-starfive-jh7110-sys.c    | 45 +++++++++++--------
>  2 files changed, 28 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/clk/starfive/Kconfig b/drivers/clk/starfive/Kconfig
> index 5195f7be5213..978b78ec08b1 100644
> --- a/drivers/clk/starfive/Kconfig
> +++ b/drivers/clk/starfive/Kconfig
> @@ -35,6 +35,7 @@ config CLK_STARFIVE_JH7110_SYS
>         select AUXILIARY_BUS
>         select CLK_STARFIVE_JH71X0
>         select RESET_STARFIVE_JH7110 if RESET_CONTROLLER
> +       select CLK_STARFIVE_JH7110_PLL
>         default ARCH_STARFIVE
>         help
>           Say yes here to support the system clock controller on the
> diff --git a/drivers/clk/starfive/clk-starfive-jh7110-sys.c b/drivers/clk/starfive/clk-starfive-jh7110-sys.c
> index e6031345ef05..d56f48013388 100644
> --- a/drivers/clk/starfive/clk-starfive-jh7110-sys.c
> +++ b/drivers/clk/starfive/clk-starfive-jh7110-sys.c
> @@ -7,6 +7,7 @@
>   */
>
>  #include <linux/auxiliary_bus.h>
> +#include <linux/clk.h>
>  #include <linux/clk-provider.h>
>  #include <linux/init.h>
>  #include <linux/io.h>
> @@ -386,6 +387,7 @@ EXPORT_SYMBOL_GPL(jh7110_reset_controller_register);
>
>  static int __init jh7110_syscrg_probe(struct platform_device *pdev)
>  {
> +       bool use_fixed_pll = true;      /* PLL clocks use fixed factor clocks or PLL driver */

nit: reverse christmas tree ordering, eg. move this below priv

>         struct jh71x0_clk_priv *priv;
>         unsigned int idx;
>         int ret;
> @@ -402,28 +404,29 @@ static int __init jh7110_syscrg_probe(struct platform_device *pdev)
>         if (IS_ERR(priv->base))
>                 return PTR_ERR(priv->base);
>
> -       /*
> -        * These PLL clocks are not actually fixed factor clocks and can be
> -        * controlled by the syscon registers of JH7110. They will be dropped
> -        * and registered in the PLL clock driver instead.
> -        */
> +       if (!IS_ERR(devm_clk_get(priv->dev, "pll0_out")))
> +               use_fixed_pll = false;  /* can get pll clocks from PLL driver */

The devm_clk_get() variant will allocate memory for a callback to call
clk_put() when the driver is unloaded, but proper references
associated with the consumers of the pll0_out clock are already taken
below. So unless we find a better way to detect if the pll references
are specified in the device tree or not, maybe something like this
instead:

priv->pll[0] = clk_get(priv->dev, "pll0_out);
if (IS_ERR(priv->pll[0])) {
  /* 24MHZ -> 1000.0MHz */
  priv->pll[0] = ...
  ...

} else {
  clk_put(priv->pll[0]);
  priv->pll[0] = NULL;
}

> +       /* Use fixed factor clocks if can not get the PLL clocks from DTS */
> +       if (use_fixed_pll) {
>         /* 24MHz -> 1000.0MHz */

These comments are not indented with the code, which just looks weird.

> -       priv->pll[0] = devm_clk_hw_register_fixed_factor(priv->dev, "pll0_out",
> -                                                        "osc", 0, 125, 3);
> -       if (IS_ERR(priv->pll[0]))
> -               return PTR_ERR(priv->pll[0]);
> +               priv->pll[0] = devm_clk_hw_register_fixed_factor(priv->dev, "pll0_out",
> +                                                                "osc", 0, 125, 3);
> +               if (IS_ERR(priv->pll[0]))
> +                       return PTR_ERR(priv->pll[0]);
>
>         /* 24MHz -> 1066.0MHz */
> -       priv->pll[1] = devm_clk_hw_register_fixed_factor(priv->dev, "pll1_out",
> -                                                        "osc", 0, 533, 12);
> -       if (IS_ERR(priv->pll[1]))
> -               return PTR_ERR(priv->pll[1]);
> +               priv->pll[1] = devm_clk_hw_register_fixed_factor(priv->dev, "pll1_out",
> +                                                                "osc", 0, 533, 12);
> +               if (IS_ERR(priv->pll[1]))
> +                       return PTR_ERR(priv->pll[1]);
>
>         /* 24MHz -> 1188.0MHz */
> -       priv->pll[2] = devm_clk_hw_register_fixed_factor(priv->dev, "pll2_out",
> -                                                        "osc", 0, 99, 2);
> -       if (IS_ERR(priv->pll[2]))
> -               return PTR_ERR(priv->pll[2]);
> +               priv->pll[2] = devm_clk_hw_register_fixed_factor(priv->dev, "pll2_out",
> +                                                                "osc", 0, 99, 2);
> +               if (IS_ERR(priv->pll[2]))
> +                       return PTR_ERR(priv->pll[2]);
> +       }
>
>         for (idx = 0; idx < JH7110_SYSCLK_END; idx++) {
>                 u32 max = jh7110_sysclk_data[idx].max;
> @@ -462,8 +465,14 @@ static int __init jh7110_syscrg_probe(struct platform_device *pdev)
>                                 parents[i].fw_name = "tdm_ext";
>                         else if (pidx == JH7110_SYSCLK_MCLK_EXT)
>                                 parents[i].fw_name = "mclk_ext";
> -                       else
> +                       else if (use_fixed_pll)

else if (priv->pll[0])

>                                 parents[i].hw = priv->pll[pidx - JH7110_SYSCLK_PLL0_OUT];
> +                       else if (pidx == JH7110_SYSCLK_PLL0_OUT)
> +                               parents[i].fw_name = "pll0_out";
> +                       else if (pidx == JH7110_SYSCLK_PLL1_OUT)
> +                               parents[i].fw_name = "pll1_out";
> +                       else if (pidx == JH7110_SYSCLK_PLL2_OUT)
> +                               parents[i].fw_name = "pll2_out";
>                 }
>
>                 clk->hw.init = &init;
> --
> 2.25.1
>