Hi Shimoda-san,
On Thu, Dec 22, 2022 at 10:33 AM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
> Enable UFS device for R-Car S4-8 Spider CPU board.
>
> Note that the conditions of RC21012 on the Spider are:
> - OUT11 (for UFS30_REFCLK_V) is disabled as default.
> - OUT11 is controlled by GPIO0 pin.
> - The GPIO0 pin is inverted sense (low active) and pull-up enabled.
Thanks for your patch!
> To output the clock, pin 4 of TCA9554 on the Spider board needs to
> output low level so that using "gpio-gate-clock" for it.
Does this mean the GPIO setup was the only missing part,
and the i2c commands from [1] were not needed?
I wanted to give this a try, but the remote Spider is offline.
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> ---
> .../boot/dts/renesas/r8a779f0-spider-cpu.dtsi | 37 +++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/renesas/r8a779f0-spider-cpu.dtsi b/arch/arm64/boot/dts/renesas/r8a779f0-spider-cpu.dtsi
> index 25b34d66061a..32625afc74bf 100644
> --- a/arch/arm64/boot/dts/renesas/r8a779f0-spider-cpu.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r8a779f0-spider-cpu.dtsi
> @@ -5,6 +5,7 @@
> * Copyright (C) 2021 Renesas Electronics Corp.
> */
>
> +#include <dt-bindings/gpio/gpio.h>
> #include "r8a779f0.dtsi"
>
> / {
> @@ -32,6 +33,12 @@ memory@480000000 {
> reg = <0x4 0x80000000 0x0 0x80000000>;
> };
>
> + rc21012_ufs: clk-rc21012-ufs {
> + compatible = "fixed-clock";
> + clock-frequency = <38400000>;
> + #clock-cells = <0>;
> + };
So you're modelling the RC21012 output as a fixed clock.
I guess that's acceptable until a proper driver is available.
> +&ufs30_clk {
> + compatible = "gpio-gate-clock";
> + clocks = <&rc21012_ufs>;
> + enable-gpios = <&gpio_exp_20 4 GPIO_ACTIVE_LOW>;
Perhaps the "clock-frequency" property should be removed using
/delete-property/?
> +};
Alternatively, you could have kept ufs30_clk as a fixed-clock, dropped
rc21012_ufs, and added a gpio hog.
But I do like your description, as it clearly shows how the GPIO interacts
with the RC21012.
The i2c part LGTM, and is identical to [2].
[1] "https://lore.kernel.org/all/20220603110524.1997825-1-yoshihiro.shimoda.uh@xxxxxxxxxxx";
https://lore.kernel.org/all/20220603110524.1997825-1-yoshihiro.shimoda.uh@xxxxxxxxxxx
[2] "[PATCH] arm64: dts: renesas: spider-cpu: add i2c0 bus"
https://lore.kernel.org/all/20221220121959.45779-1-wsa+renesas@xxxxxxxxxxxxxxxxxxxx
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
