Re: [PATCH 3/4] include: dt-bindings: Add more GPIO bank and index definition for rockchip pinctrl

From: Heiko Stuebner
Date: Mon Sep 05 2016 - 18:15:56 EST


Am Montag, 5. September 2016, 18:22:46 CEST schrieb Andy Yan:
> Hi Heiko:
>
> On 2016å09æ05æ 17:33, Heiko Stuebner wrote:
> > Hi Andy,
> >
> > Am Sonntag, 4. September 2016, 16:35:30 CEST schrieb Andy Yan:
> >> There are 8 gpio banks on RK3288, so add the missing
> >> RK_GPIO7 and RK_GPIO8. Also add gpio index definition
> >> to make it easier to description GPIO in dts.
> >>
> >> Signed-off-by: Andy Yan <andy.yan@xxxxxxxxxxxxxx>
> >
> > I tend to disagree here.
> >
> > I consider the bank defines RK_GPIOx to be deprecated and highly
> > discourage
> > them being used in new boards. They only encode the same number again (2
> > ->
> > RK_GPIO2 etc) and therefore don't bring any useful addition over using the
> > bank number directly.
> >
> > Slightly similar argument for the per-pin defines. While the external pins
> > are described in the A/B/C/Dx notation for pinmux purposes, the gpio
> > controllers on top use a regular 0-31 numbering. Also you cannot name
> > constants generic GPIO_x, simply because that may conflict with other
> > overly generic constant names.
> >
> > So I'm not yet convinced that these improve readability, but they would
> > definitly need a RK_* prefix to make them specific.
> >
> >
> > Heiko
>
> I consider for a people who doesn't familiar with rockchip
> pinctrl, He
> may don't know what does these number 2/4/17....stands for in the dts
> like
> rockchip,pins = <2 17 RK_FUNC_GPIO &pcfg_pull_up>.

That person shouldn't work on devicetrees anyway :-) ... or simply read the
dt-binding for the pinctrl at first ... which should normally really be the
first step, otherwise we wouldn't need the binding documentation.

> But if we use meaningful macro here like : rockchip,pins =
> <RK_GPIO2 RK_GPIO_C0 RK_FUNC_GPIO &pcfg_pull_up>, I think it easier to
> tell people this GPIO is GPIO_C0 of BNAK2.

I definitly don't agree for the gpio-bank number, see above .

> Especially all the GPIOs in rockchip based schematic are described as
> GPIOn_A/B/C/Dx. And it is also easier for people to directly use a macro
> stands for 0~32 than translating A/B/C/Dx from the schematic to 0~32.

But the pins might in fact really be helpful, but definitly need a prefix and
maybe even distinguish between pin and gpio, aka RK_PIN_A0 etc?


Heiko

>
> >> ---
> >>
> >> include/dt-bindings/pinctrl/rockchip.h | 35
> >>
> >> ++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+)
> >>
> >> diff --git a/include/dt-bindings/pinctrl/rockchip.h
> >> b/include/dt-bindings/pinctrl/rockchip.h index 743e66a..fd35350 100644
> >> --- a/include/dt-bindings/pinctrl/rockchip.h
> >> +++ b/include/dt-bindings/pinctrl/rockchip.h
> >> @@ -24,6 +24,41 @@
> >>
> >> #define RK_GPIO3 3
> >> #define RK_GPIO4 4
> >> #define RK_GPIO6 6
> >>
> >> +#define RK_GPIO7 7
> >> +#define RK_GPIO8 8
> >> +
> >> +#define GPIO_A0 0
> >> +#define GPIO_A1 1
> >> +#define GPIO_A2 2
> >> +#define GPIO_A3 3
> >> +#define GPIO_A4 4
> >> +#define GPIO_A5 5
> >> +#define GPIO_A6 6
> >> +#define GPIO_A7 7
> >> +#define GPIO_B0 8
> >> +#define GPIO_B1 9
> >> +#define GPIO_B2 10
> >> +#define GPIO_B3 11
> >> +#define GPIO_B4 12
> >> +#define GPIO_B5 13
> >> +#define GPIO_B6 14
> >> +#define GPIO_B7 15
> >> +#define GPIO_C0 16
> >> +#define GPIO_C1 17
> >> +#define GPIO_C2 18
> >> +#define GPIO_C3 19
> >> +#define GPIO_C4 20
> >> +#define GPIO_C5 21
> >> +#define GPIO_C6 22
> >> +#define GPIO_C7 23
> >> +#define GPIO_D0 24
> >> +#define GPIO_D1 25
> >> +#define GPIO_D2 26
> >> +#define GPIO_D3 27
> >> +#define GPIO_D4 28
> >> +#define GPIO_D5 29
> >> +#define GPIO_D6 30
> >> +#define GPIO_D7 31
> >>
> >> #define RK_FUNC_GPIO 0
> >> #define RK_FUNC_1 1