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From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
To: Jerome Brunet <jbrunet@baylibre.com>
Cc: devicetree@vger.kernel.org,
	Neil Armstrong <narmstrong@baylibre.com>,
	khilman@baylibre.com, linux-kernel@vger.kernel.org,
	linux-amlogic@lists.infradead.org, linux-clk@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/6] clk: meson: add a driver for the Meson8/8b/8m2 DDR clock controller
Date: Tue, 1 Oct 2019 20:53:59 +0200	[thread overview]
Message-ID: <CAFBinCCED4YWYkdtrfrC80C8WLE=fyMJdjTa3wFNMJgC1OsoOA@mail.gmail.com> (raw)
In-Reply-To: <1jftkcr3uy.fsf@starbuckisacylon.baylibre.com>

Hi Jerome,

thank you for taking the time to go through this!

On Tue, Oct 1, 2019 at 3:29 PM Jerome Brunet <jbrunet@baylibre.com> wrote:
[...]
> > +#include <linux/platform_device.h>
> > +#include <linux/mfd/syscon.h>
>
> syscon is not used in the driver
oops, good catch - thank you

[...]
> > +static struct clk_hw_onecell_data meson8_ddr_clk_hw_onecell_data = {
> > +     .hws = {
> > +             [DDR_CLKID_DDR_PLL_DCO]         = &meson8_ddr_pll_dco.hw,
> > +             [DDR_CLKID_DDR_PLL]             = &meson8_ddr_pll.hw,
>
> I wonder if onecell is not overkill for this driver. We won't expose the
> DCO, so only the post divider remains
>
> Do you expect this provider to have more than one leaf clock ?
> If not, maybe you could use of_clk_hw_simple_get() instead ?
there's some more clock bits in DDR_CLK_CNTL - the public A311D
datasheet has a description for these bits but I'm not sure they do
the same on Meson8/Meson8b/Meson8m2
all I know is that some magic bytes are written to DDR_CLK_CNTL in the
old u-boot code

that's why I don't want to make any assumptions and play safe here (by
using a onecell clock provider)

> > +     },
> > +     .num = 2,
> > +};
> > +
> > +static struct clk_regmap *const meson8_ddr_clk_regmaps[] = {
> > +     &meson8_ddr_pll_dco,
> > +     &meson8_ddr_pll,
> > +};
> > +
> > +static const struct regmap_config meson8_ddr_clkc_regmap_config = {
> > +     .reg_bits = 8,
> > +     .val_bits = 32,
> > +     .reg_stride = 4,
> > +     .fast_io = true,
>
> I think fast_io will default to true with memory based register.
> Setting the max_register would be nice
good point - I'll take care of this when sending v2


Martin

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  reply	other threads:[~2019-10-01 18:54 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-21 15:18 [PATCH 0/6] add the DDR clock controller on Meson8 and Meson8b Martin Blumenstingl
2019-09-21 15:18 ` [PATCH 1/6] dt-bindings: clock: add the Amlogic Meson8 DDR clock controller binding Martin Blumenstingl
2019-10-02 14:19   ` Rob Herring
2019-09-21 15:18 ` [PATCH 2/6] clk: meson: add a driver for the Meson8/8b/8m2 DDR clock controller Martin Blumenstingl
2019-10-01 13:29   ` Jerome Brunet
2019-10-01 18:53     ` Martin Blumenstingl [this message]
2019-10-02  9:04       ` Jerome Brunet
2019-09-21 15:18 ` [PATCH 3/6] clk: meson: meson8b: use of_clk_hw_register to register the clocks Martin Blumenstingl
2019-09-21 15:18 ` [PATCH 4/6] clk: meson: meson8b: add the ddr_pll input for the audio clocks Martin Blumenstingl
2019-09-21 15:18 ` [PATCH 5/6] ARM: dts: meson8: add the DDR clock controller Martin Blumenstingl
2019-09-21 15:18 ` [PATCH 6/6] ARM: dts: meson8b: " Martin Blumenstingl
2019-09-23 10:06 ` [PATCH 0/6] add the DDR clock controller on Meson8 and Meson8b Jerome Brunet
2019-09-23 20:49   ` Martin Blumenstingl
2019-10-01 13:33     ` Jerome Brunet

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