Re: [RFC v1 1/2] scmi: Introduce pinctrl SCMI protocol driver

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Fri, Apr 21, 2023 at 10:40 AM Oleksii Moisieiev
<Oleksii_Moisieiev@xxxxxxxx> wrote:
> On 17.04.23 05:55, Peng Fan wrote:
> > On 4/13/2023 6:04 AM, Cristian Marussi wrote:

> > Is it possible to extend the spec to support multilple uint32_t for PIN
> > CONFIG SET?
> >
> > With only one uint32_t could not satisfy i.MX requirement.
> >
> > Thanks,
> > Peng.
> >
> IIUC you are expecting to have an ability to set some kind of array of
> uint32_t config values to some specific ConfigType?
>
> I'm not sure if it's supported by pintctrl subsystem right now. I was
> unable to find an example in the existing device-tree pinctrl bindings.
> This makes me think that this kind of binding is OEM specific.
>
> Maybe it can be implemented by adding new IDs to OEM specific range
> (192-255) which is reserved for OEM specific units (See Table 23 of
> DEN0056E).

>From a pinctrl point of view I do not understand this requirement.

The pinctrl subsystem in the Linux kernel certainly does not support
an array of u32 for the pin config, we only support passing a single
u32 value along with the enumerator (config type), or well it is
actually 24 bits in Linux, the uppermost 8 bits is for the config type:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/pinctrl/pinconf-generic.h

/*
 * Helpful configuration macro to be used in tables etc.
 */
#define PIN_CONF_PACKED(p, a) ((a << 8) | ((unsigned long) p & 0xffUL))

p = parameter (PIN_CONFIG_DRIVE_STRENGTH etc)
a = argument (value such as in mA)

Yours,
Linus Walleij