Hi Linus,
On Mon, Sep 3, 2018 at 11:51 PM Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
> Some 3WIRE SPI devices require the host to insert a "high
> impedance turnaround" essentially a clock pulse after
high-impedance
(English allows both, but since you use "turn-around")
> switching the one line from output to input.
>
> This is needed to support the TPO TPG110 panel to use
> the 3WIRE SPI bindings.
>
> Cc: devicetree@xxxxxxxxxxxxxxx
> Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
> Cc: Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Thanks for your patch!
> --- a/Documentation/devicetree/bindings/spi/spi-bus.txt
> +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt
> @@ -70,6 +70,10 @@ All slave nodes can contain the following optional properties:
> - spi-cs-high - Empty property indicating device requires chip select
> active high.
> - spi-3wire - Empty property indicating device requires 3-wire mode.
> +- spi-3wire-high-impedance-turnaround - Empty property indicating that a
> + 3wire host need to insert a high impedance turn-around
needs
high-impedance
> + clock cycle after turning the one output line into an
> + input line.
> - spi-lsb-first - Empty property indicating device requires LSB first mode.
> - spi-tx-bus-width - The bus width (number of data wires) that is used for MOSI.
> Defaults to 1 if not present.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
