Messages in this thread | | | Subject | Re: [PATCH 03/16] dt-bindings: spi: Add spi peripheral specific property | From | William Zhang <> | Date | Fri, 6 Jan 2023 19:27:34 -0800 |
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Hi Mark,
On 01/06/2023 01:14 PM, Mark Brown wrote: > On Fri, Jan 06, 2023 at 12:07:55PM -0800, William Zhang wrote: > >> brcm,no-clk-gate is a Broadcom Broadband HS SPI controller specific >> property for certain SPI device such as Broadcom ISI voice daughtercard >> to work properly. It disables the clock gating feature when the chip >> select is deasserted for any device that wants to keep the clock >> running. > > Why would this property be Broadcom specific? Other devices could in > theory implement this. > It does not need to be Broadcom specific if other SoC's SPI bus controller support such function. I am not aware of such case but certainly I am no expert on other chips. I can put it in the generic spi-peripheral-props.yaml if that is what you suggest.
>> +properties: >> + brcm,no-clk-gate: >> + $ref: /schemas/types.yaml#/definitions/flag >> + description: >> + Some SPI device such as Broadcom ISI based voice daughtercard requires SPI >> + clock running even when chip select is deasserted. By default the >> + controller turns off or gate the clock when cs is not active to save >> + power. This flag tells the controller driver to keep the clock running >> + when chip select is not active. > > This seems problematic with any host controlled chip select support... > Yes those ISI chip based voice cards do need such strange requirement and will not work with other controller. That is one of the reason I put this as Broadcom specific option. [unhandled content-type:application/pkcs7-signature] | |