Re: [PATCH 03/16] dt-bindings: spi: Add spi peripheral specific property

From: Mark Brown
Date: Fri Jan 06 2023 - 16:15:07 EST


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.

> +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...

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