Re: [PATCH v4 3/7] dt-bindings: clock: jh7110-syscrg: Add PLL clock inputs

From: Xingyu Wu <xingyu.wu@starfivetech.com>
To: Conor Dooley <conor.dooley@microchip.com>
Cc: <linux-riscv@lists.infradead.org>, <devicetree@vger.kernel.org>,
	"Michael Turquette" <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Conor Dooley <conor@kernel.org>,
	"Emil Renner Berthing" <kernel@esmil.dk>,
	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>,
	William Qiu <william.qiu@starfivetech.com>,
	<linux-kernel@vger.kernel.org>, <linux-clk@vger.kernel.org>
Subject: Re: [PATCH v4 3/7] dt-bindings: clock: jh7110-syscrg: Add PLL clock inputs
Date: Fri, 19 May 2023 16:26:16 +0800	[thread overview]
Message-ID: <1db26f8d-6214-1195-dee7-871b04b4c0b2@starfivetech.com> (raw)
In-Reply-To: <20230519-gosling-rewrap-bfd03dc549ae@wendy>

On 2023/5/19 16:12, Conor Dooley wrote:
> On Fri, May 19, 2023 at 03:59:19PM +0800, Xingyu Wu wrote:
>> On 2023/5/12 21:49, Conor Dooley wrote:
>> > On Fri, May 12, 2023 at 05:56:16PM +0800, Xingyu Wu wrote:
>> >> On 2023/5/12 17:35, Conor Dooley wrote:
>> >> > On Fri, May 12, 2023 at 04:07:47PM +0800, Xingyu Wu wrote:
>> >> >> On 2023/5/12 14:47, Conor Dooley wrote:
>> >> >> > On Fri, May 12, 2023 at 10:20:32AM +0800, Xingyu Wu wrote:
>> >> >> >> Add PLL clock inputs from PLL clock generator.
>> >> >> >> 
>> >> >> >> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>> >> >> >> Signed-off-by: Xingyu Wu <xingyu.wu@starfivetech.com>
>> >> >> >> ---
>> >> >> >>  .../clock/starfive,jh7110-syscrg.yaml         | 20 +++++++++++++++++--
>> >> >> >>  1 file changed, 18 insertions(+), 2 deletions(-)
>> >> >> > 
>> >> >> > /tmp/tmp.KDlzwQM5ma/arch/riscv/boot/dts/starfive/jh7110-starfive-visionfive-2-v1.3b.dtb: clock-controller@13020000: clocks: 'oneOf' conditional failed, one must be fixed:
>> >> >> > 	[[19], [20], [21], [22], [23], [24], [25], [26], [27]] is too short
>> >> >> > 	From schema: /Documentation/devicetree/bindings/clock/starfive,jh7110-syscrg.yaml
>> >> >> > /tmp/tmp.KDlzwQM5ma/arch/riscv/boot/dts/starfive/jh7110-starfive-visionfive-2-v1.3b.dtb: clock-controller@13020000: clock-names: 'oneOf' conditional failed, one must be fixed:
>> >> >> > 	['osc', 'gmac1_rmii_refin', 'gmac1_rgmii_rxin', 'i2stx_bclk_ext', 'i2stx_lrck_ext', 'i2srx_bclk_ext', 'i2srx_lrck_ext', 'tdm_ext', 'mclk_ext'] is too short
>> >> >> > 	'i2stx_bclk_ext' was expected
>> >> >> > 	'i2stx_lrck_ext' was expected
>> >> >> > 	'i2srx_bclk_ext' was expected
>> >> >> > 	'i2srx_lrck_ext' was expected
>> >> >> > 	'tdm_ext' was expected
>> >> >> > 	'mclk_ext' was expected
>> >> >> > 	'pll0_out' was expected
>> >> >> > 	From schema: /Documentation/devicetree/bindings/clock/starfive,jh7110-syscrg.yaml
>> >> >> > /tmp/tmp.KDlzwQM5ma/arch/riscv/boot/dts/starfive/jh7110-starfive-visionfive-2-v1.2a.dtb: clock-controller@13020000: clocks: 'oneOf' conditional failed, one must be fixed:
>> >> >> > 	[[19], [20], [21], [22], [23], [24], [25], [26], [27]] is too short
>> >> >> > 	From schema: Documentation/devicetree/bindings/clock/starfive,jh7110-syscrg.yaml
>> >> >> > /tmp/tmp.KDlzwQM5ma/arch/riscv/boot/dts/starfive/jh7110-starfive-visionfive-2-v1.2a.dtb: clock-controller@13020000: clock-names: 'oneOf' conditional failed, one must be fixed:
>> >> >> > 	['osc', 'gmac1_rmii_refin', 'gmac1_rgmii_rxin', 'i2stx_bclk_ext', 'i2stx_lrck_ext', 'i2srx_bclk_ext', 'i2srx_lrck_ext', 'tdm_ext', 'mclk_ext'] is too short
>> >> >> > 	'i2stx_bclk_ext' was expected
>> >> >> > 	'i2stx_lrck_ext' was expected
>> >> >> > 	'i2srx_bclk_ext' was expected
>> >> >> > 	'i2srx_lrck_ext' was expected
>> >> >> > 	'tdm_ext' was expected
>> >> >> > 	'mclk_ext' was expected
>> >> >> > 	'pll0_out' was expected
>> >> >> > 	Documentation/devicetree/bindings/clock/starfive,jh7110-syscrg.yaml
>> >> >> > 
>> >> >> > This binding change is incompatible with the existing devicetrees for
>> >> >> > the visionfive 2.
>> >> >> 
>> >> >> This looks like less clocks about PLL in SYSCRG node. And I add this in patch 7.
>> >> > 
>> >> > The existing devicetree is a valid, albeit limited, description of the
>> >> > hardware.
>> >> > After your changes to the clock driver in this series, but *without* the
>> >> > changes to the devicetrees, does the system still function?
>> >> > From a quick check of 4/7, it looks like it will not?
>> >> 
>> >> I just tested it on the board and the system still worked without the changes
>> >> about devicetree. But these clocks' rate were 0 because these could not get
>> >> the PLL clocks from devicetree.
>> > 
>> > Hmm, that sounds like an issue to me. If all of the clock rates are
>> > computed based off of parents that incorrectly report 0, are we not in
>> > for trouble?
>> > Should the fixed-factor clocks be retained as a fallback for the sake of
>> > compatibility?
>> > Emil, Stephen?
>> 
>> I got your concern. Actually, I can add a check in driver to see if the dts
>> has pll clocks and then decide whether to use fixed-factor clocks or pll clocks
>> from syscon. But eventually we have to use pll clocks and dts has to add it.
>> Then the binding should add it synchronously, right?
> 
> IMO, it is okay to change the bindings to only allow the "correct"
> representation of the clock tree, but the driver should fall back to the
> fixed factor clocks if it detects the old/limited configuration.
> 

Great, I will follow it.

Best regards,
Xingyu Wu