From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Frank Li <frank.li@nxp.com>, "shawnguo@kernel.org" <shawnguo@kernel.org>
Cc: "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"festevam@gmail.com" <festevam@gmail.com>,
"imx@lists.linux.dev" <imx@lists.linux.dev>,
"kernel@pengutronix.de" <kernel@pengutronix.de>,
"krzysztof.kozlowski+dt@linaro.org"
<krzysztof.kozlowski+dt@linaro.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
dl-linux-imx <linux-imx@nxp.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>
Subject: Re: [EXT] Re: [PATCH v2 1/3] dt-bindings: usb: cdns-imx8qm: add imx8qm cdns3 glue bindings
Date: Mon, 20 Mar 2023 16:23:01 +0100 [thread overview]
Message-ID: <b8801c83-f2dc-f144-de58-03e5c24436fd@linaro.org> (raw)
In-Reply-To: <AM6PR04MB483800D7CDCC7AF48F88BF9688809@AM6PR04MB4838.eurprd04.prod.outlook.com>
On 20/03/2023 15:49, Frank Li wrote:
>>>>> + clock-names:
>>>>> + items:
>>>>> + - const: usb3_lpm_clk
>>>>> + - const: usb3_bus_clk
>>>>> + - const: usb3_aclk
>>>>> + - const: usb3_ipg_clk
>>>>> + - const: usb3_core_pclk
>>>>> +
>>>>> + assigned-clocks:
>>>>> + items:
>>>>> + - description: Phandle and clock specifier of IMX_SC_PM_CLK_PER.
>>>>> + - description: Phandle and clock specifoer of
>> IMX_SC_PM_CLK_MISC.
>>>>> + - description: Phandle and clock specifoer of
>>>> IMX_SC_PM_CLK_MST_BUS.
>>>>> +
>>>>> + assigned-clock-rates:
>>>>> + items:
>>>>> + - description: Must be 125 Mhz.
>>>>> + - description: Must be 12 Mhz.
>>>>> + - description: Must be 250 Mhz.
>>>>
>>>> I would argue that both properties above are not needed. If your
>>>> hardware requires fixed frequencies, clock provider can fix them, can't it?
>>>
>>> Clock provider don't know fixed value and turn on only used by client.
>>
>> So maybe fix the clock provider? Or this device driver? Requiring by
>> binding specific frequencies for every board is a bit redundant.
>
> It is not for every boards, it is common for a chip family. Only a place to set for
> QM and QXP.
>
> The similar case is network driver, which require a specific frequency at clock assign.
> Generally frequency is fixed, clock source name may change at difference chips.
If frequency is always fixed, I don't understand why this is in DT
bindings. I would even say it should not be in DTS. We don't put into
DTS properties which are always the same, because otherwise they would
grow crazy big.
Best regards,
Krzysztof
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next prev parent reply other threads:[~2023-03-20 15:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-16 21:27 [PATCH v2 0/3] dts: imx8qxp add cdns usb3 port Frank Li
2023-03-16 21:27 ` [PATCH v2 1/3] dt-bindings: usb: cdns-imx8qm: add imx8qm cdns3 glue bindings Frank Li
2023-03-17 9:09 ` Krzysztof Kozlowski
2023-03-17 14:55 ` [EXT] " Frank Li
2023-03-19 11:13 ` Krzysztof Kozlowski
2023-03-20 14:49 ` Frank Li
2023-03-20 15:23 ` Krzysztof Kozlowski [this message]
2023-03-20 16:22 ` Frank Li
2023-03-20 16:27 ` Krzysztof Kozlowski
2023-03-20 17:02 ` Frank Li
2023-03-20 17:28 ` Krzysztof Kozlowski
2023-03-20 19:59 ` Frank Li
2023-03-21 6:37 ` Krzysztof Kozlowski
2023-03-16 21:27 ` [PATCH v2 2/3] arm64: dts: imx8qxp: add cadence usb3 support Frank Li
2023-03-17 6:39 ` Alexander Stein
2023-03-17 15:05 ` [EXT] " Frank Li
2023-03-16 21:27 ` [PATCH v2 3/3] arm64: dts: freescale: imx8qxp-mek: enable cadence usb3 Frank Li
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