Hi Geert-san,
> From: Geert Uytterhoeven, Sent: Thursday, January 12, 2023 1:20 AM
>
> 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!
Thank you for your review!
> > 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?
You're correct.
> I wanted to give this a try, but the remote Spider is offline.
IIUC, Morimoto-san is preparing a new remote lab now...
> > 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.
Yes.
> I guess that's acceptable until a proper driver is available.
Good!
> > +&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/?
I see. I'll fix it on v2.
> > +};
>
> Alternatively, you could have kept ufs30_clk as a fixed-clock, dropped
> rc21012_ufs, and added a gpio hog.
Yes, I had tried using a gpio hog, and it also worked.
> But I do like your description, as it clearly shows how the GPIO interacts
> with the RC21012.
I got it. Thanks!
> The i2c part LGTM, and is identical to [2].
Thanks!
Best regards,
Yoshihiro Shimoda
