Re: [PATCH v4 07/10] clk: starfive: Add StarFive JH7110 Video-Output clock driver

From: Conor Dooley <conor.dooley@microchip.com>
To: Stephen Boyd <sboyd@kernel.org>
Cc: Conor Dooley <conor@kernel.org>,
	Emil Renner Berthing <kernel@esmil.dk>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Xingyu Wu <xingyu.wu@starfivetech.com>,
	<devicetree@vger.kernel.org>, <linux-riscv@lists.infradead.org>,
	Rob Herring <robh+dt@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>,
	<linux-kernel@vger.kernel.org>, <linux-clk@vger.kernel.org>
Subject: Re: [PATCH v4 07/10] clk: starfive: Add StarFive JH7110 Video-Output clock driver
Date: Thu, 13 Apr 2023 14:52:44 +0100	[thread overview]
Message-ID: <20230413-hardcover-ground-efbd862c5ec3@wendy> (raw)
In-Reply-To: <cd4a11ae65e186799145410969d40421.sboyd@kernel.org>

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On Wed, Apr 12, 2023 at 09:04:08PM -0700, Stephen Boyd wrote:
> Quoting Xingyu Wu (2023-04-11 23:15:26)
> > On 2023/4/12 2:33, Stephen Boyd wrote:
> > > Quoting Xingyu Wu (2023-04-11 06:55:55)

> > >> +       if (ret < 0)
> > >> +               return dev_err_probe(priv->dev, ret, "failed to turn on power\n");
> > >> +
> > >> +       ret = jh7110_vout_top_crg_init(priv, top);
> > >> +       if (ret)
> > >> +               goto err_clk;
> > >> +
> > >> +       top->base = priv->base;
> > >> +       dev_set_drvdata(priv->dev, (void *)(&top->base));
> > > 
> > > See comment later about setting this to 'top' instead. Casting away
> > > iomem markings is not good hygiene.
> > 
> > JH7110 resets as the auxiliary device of clocks use the same iomem as the clocks
> > and the iomem will be got by dev_get_drvdata() in the 7110 reset drivers when registering reset.
> > So I follow the basic 7110 reset driver and also set the iomem not top_crg struct.
> 
> Oh I totally missed that this is how it's been done for the other
> starfive driver. It's still not good hygiene to stash the iomem pointer
> that way because the iomem marking is lost and has to be recovered. Can
> you make a wrapper struct, either for the adev or to pass in struct
> device::platform_data?

FWIW, this did come up on an earlier version of the other starfive
driver:
https://lore.kernel.org/linux-clk/e0d8f9ba-5bf4-d7dd-5110-20d4196556f9@starfivetech.com/

I probably should've pushed Hal to use a struct, but evidently I didn't
reply to his final message there, so apologies for that!

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