Re: [PATCH v2 3/5] dt-bindings: Document common property for daisy-chained devices

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Thu, Oct 12, 2017 at 12:40 PM, Lukas Wunner <lukas@xxxxxxxxx> wrote:

> Many serially-attached GPIO and IIO devices are daisy-chainable.
>
>     Examples for GPIO devices are Maxim MAX3191x and TI SN65HVS88x:
>     https://datasheets.maximintegrated.com/en/ds/MAX31913.pdf
>     http://www.ti.com/lit/ds/symlink/sn65hvs880.pdf
>
>     Examples for IIO devices are TI DAC128S085 and TI DAC161S055:
>     http://www.ti.com/lit/ds/symlink/dac128s085.pdf
>     http://www.ti.com/lit/ds/symlink/dac161s055.pdf
>
> We already have drivers for daisy-chainable devices in the tree but
> their devicetree bindings are somewhat inconsistent and ill-named:
>
>     The gpio-74x164.c driver uses "registers-number" to convey the
>     number of devices in the daisy-chain.  (Sans vendor prefix,
>     multiple vendors sell compatible versions of this chip.)
>
>     The gpio-pisosr.c driver takes a different approach and calculates
>     the number of devices in the daisy-chain by dividing the common
>     "ngpios" property (Documentation/devicetree/bindings/gpio/gpio.txt)
>     by 8 (which assumes that each chip has 8 inputs).
>
> Let's standardize on a common "#daisy-chained-devices" property.
> That name was chosen because it's the term most frequently used in
> datasheets.  (A less frequently used synonym is "cascaded devices".)
>
> Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
> ---
> Changes v1 -> v2:
>
> - Newly inserted patch.

Patch applied with the ACKs.

Yours,
Linus Walleij
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