Hi Shimoda-san,
On Thu, Oct 12, 2017 at 1:41 PM, Yoshihiro Shimoda
<yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
>> From: Vladimir Barinov, Sent: Saturday, October 7, 2017 2:29 AM
>> On 06.10.2017 10:15, Geert Uytterhoeven wrote:
>> > CC Shimoda-san
>> >
>> > On Fri, Oct 6, 2017 at 4:38 AM, Vladimir Barinov
>> > <vladimir.barinov@xxxxxxxxxxxxxxxxxx> wrote:
>> >> On 20.09.2017 15:59, Geert Uytterhoeven wrote:
>> >>> On Thu, Sep 7, 2017 at 12:36 AM, Vladimir Barinov
>> >>> <vladimir.barinov@xxxxxxxxxxxxxxxxxx> wrote:
>> >>>> This supports USB2 PHY channel #0 on ULCB Kingfisher board
>> >>>>
>> >>>> Signed-off-by: Vladimir Barinov <vladimir.barinov@xxxxxxxxxxxxxxxxxx>
>> >>> Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
>> >>>
>> >>>> index ca8de1a..0854600 100644
>> >>>> --- a/arch/arm64/boot/dts/renesas/ulcb-kf.dtsi
>> >>>> +++ b/arch/arm64/boot/dts/renesas/ulcb-kf.dtsi
>> >>>> @@ -60,6 +60,11 @@
>> >>>> groups = "scif1_data_b";
>> >>>> function = "scif1";
>> >>>> };
>> >>>> +
>> >>>> + usb0_pins: usb0 {
>> >>>> + groups = "usb0";
>> >>>> + function = "usb0";
>> >>>> + };
>> >>>> };
>> >>>>
>> >>>> &scif1 {
>> >>>> @@ -68,3 +73,10 @@
>> >>>>
>> >>>> status = "okay";
>> >>>> };
>> >>>> +
>> >>>> +&usb2_phy0 {
>> >>>> + pinctrl-0 = <&usb0_pins>;
>> >>>> + pinctrl-names = "default";
>> >>>> +
>> >>> Don't you need
>> >>>
>> >>> vbus-supply = <&vbus0_usb2>;
>> >>>
>> >>> with vbus0_usb2 a fixed regulator controlled by GPIO P11 (OTG_EXTLPn) from
>> >>> GPIO expander U11 (TCA9539)?
>> >>> May be optional, though. salvator-common.dtsi has it.
>> >> Yes, I need this gpio.
>> >> I need both OTG_EXTLPn and OTG_OFFVBUSn from the same gpio expander.
>> >>
>> >> I've been considering to use either vbus-supply + gpio hog or use gpio hog
>> >> for both of them for consistency.
>> >> What do you think about this?
>> > For OTG_EXTLPn you don't really need a hog, as it will be controlled by the
>> > USB driver/subsystem, like on Salvator-X(S), right?
>> Agreed.
>> >
>> > For OTG_OFFVBUSn, which is (optionally) driven from USB0_PWEN on
>> > Salvator-X(S) I don't know if you need a GPIO hog or not. I have to defer your
>> > question to Shimoda-san.
>
> I'm sorry for the delayed response.
> I think OTG_OFFVBUSn should be low level to avoid conflict 5V supply from U13's OUT pins.
>
>> This pin should be tied permanently low to disable internal MAX3355
>> internal VBUS charge pump.
>
> I agree.
OK.
>> Hence probably gpio hog is enough for OTG_OFFVBUSn.
>
> I'm afraid but I don't understand this "gpio hog" means.
"gpio hog" is a means to tie a GPIO to a specific level, cfr.
Documentation/devicetree/bindings/gpio/gpio.txt.
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
