linux-kernel - Re: [PATCH v1 03/11] clk: starfive: Add StarFive JH7110 System-Top-Group clock driver

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Date:   Tue, 31 Jan 2023 14:51:06 +0800
From:   Xingyu Wu <xingyu.wu@...rfivetech.com>
To:     Stephen Boyd <sboyd@...nel.org>,
        Emil Renner Berthing <kernel@...il.dk>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Michael Turquette <mturquette@...libre.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        <devicetree@...r.kernel.org>, <linux-riscv@...ts.infradead.org>
CC:     Rob Herring <robh+dt@...nel.org>, Conor Dooley <conor@...nel.org>,
        "Paul Walmsley" <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Hal Feng <hal.feng@...rfivetech.com>,
        <linux-kernel@...r.kernel.org>, <linux-clk@...r.kernel.org>
Subject: Re: [PATCH v1 03/11] clk: starfive: Add StarFive JH7110
 System-Top-Group clock driver

On 2023/1/31 8:35, Stephen Boyd wrote:
> Quoting Xingyu Wu (2023-01-30 00:02:28)
>> On 2023/1/26 10:33, Stephen Boyd wrote:
>> > Quoting Xingyu Wu (2023-01-19 18:44:37)
>> >> diff --git a/drivers/clk/starfive/clk-starfive-jh7110-stg.c b/drivers/clk/starfive/clk-starfive-jh7110-stg.c
>> >> new file mode 100644
>> >> index 000000000000..c2740f44e796
>> >> --- /dev/null
>> >> +++ b/drivers/clk/starfive/clk-starfive-jh7110-stg.c
> [...]
>> >> +                               parents[i].fw_name = "nocstg_bus";
>> >> +                       else if (pidx == JH7110_STGCLK_APB_BUS)
>> >> +                               parents[i].fw_name = "apb_bus";
>> > 
>> > Can this be an array lookup instead of a pile of conditions?
>> > 
>> >       if (pidx < JH7110_STGCLK_END)
>> >               ...
>> >       else
>> >               parents[i].fw_name = fw_table[pidx - JH7110_STGCLK_END];
>> > 
>> > Or even better, don't use strings at all and just make the 'pidx' number
>> > (possibly minus the end constant) be the 'clocks' property index that
>> > you want.
>> 
>> It seen to be a good way that there uses an array.
>> Based on the another way, can I use the 'pidx' number to get the 'clock-names' property
>> to be the parent clock name?
> 
> The binding is your design. It is incorrect if the binding is referencing clocks
> provided by the same node though. If that's the case, simply use the hw
> pointer directly.

There are external clocks and some of which belong to the SYS clock part.
Our clocks are divided into SYS, AON, STG, ISP and VOUT parts and they are different nodes.
So I think I use the clock names maybe better than use the hw pointer.

> 
>> 
>> > 
>> >> +               }
>> >> +
>> >> +               clk->hw.init = &init;
>> >> +               clk->idx = idx;
>> >> +               clk->max_div = max & JH71X0_CLK_DIV_MASK;
>> >> +
>> >> +               ret = devm_clk_hw_register(&pdev->dev, &clk->hw);
>> >> +               if (ret)
>> >> +                       return ret;
>> >> +       }
>> >> +
>> >> +       ret = devm_of_clk_add_hw_provider(&pdev->dev, jh7110_stgclk_get, priv);
>> >> +       if (ret)
>> >> +               return ret;
>> >> +
>> >> +       return jh7110_reset_controller_register(priv, "reset-stg", 2);
>> > 
>> > Is this also devm-ified?
>> 
>> No, it need to be freed actively. I will advise Hal Feng this.
>> 
> 
> Oh, that's not good.

Will add this in nest patch.


Best regards,
Xingyu Wu