Re: [PATCH v4 1/3] pinctrl: Add sleep related configuration

Baolin Wang
2017-06-27T08:25:58Z

On 一, 6月 26, 2017 at 11:13:48上午 -0500, Rob Herring wrote:
> On Wed, Jun 21, 2017 at 07:55:37PM +0800, Baolin Wang wrote:
> > In some scenarios, we should set some pins as input/output/pullup/pulldown
> > when the specified system goes into deep sleep mode, then when the system
> > goes into deep sleep mode, these pins will be set automatically by hardware.
> >
> > Usually we can set the "sleep" state to set sleep related config, but one SoC
> > usually has not only one system (especially for mobile SoC), some systems on
> > the SoC which did not run linux kernel, they can not select the "sleep" state
> > when they go into deep sleep mode.
>
> The wording here is not very clear. I think what you mean is some pins
> are not controlled by any specific driver in the OS, but need to be
> controlled when entering sleep mode.

Yes, that is what I meaning, sorry for confusing.

>
> > Thus we introduce some sleep related config into pinconf-generic for users to
> > configure.
> >
> > Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> > ---
> > - Add this patch since v4.
> > ---
> > .../bindings/pinctrl/pinctrl-bindings.txt | 12 ++++++++++++
> > drivers/pinctrl/pinconf-generic.c | 10 ++++++++++
> > include/linux/pinctrl/pinconf-generic.h | 14 ++++++++++++++
> > 3 files changed, 36 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
> > index bf3f7b0..e098059 100644
> > --- a/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
> > +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
> > @@ -236,6 +236,18 @@ low-power-enable - enable low power mode
> > low-power-disable - disable low power mode
> > output-low - set the pin to output mode with low level
> > output-high - set the pin to output mode with high level
> > +sleep-bias-pull-up - pull up the pin when the specified system goes into
> > + deep sleep mode
> > +sleep-bias-pull-down - pull down the pin when the specified system goes into
> > + deep sleep mode
> > +sleep-input-enable - enable input on pin when the specified system goes
> > + into deep sleep mode (no effect on output)
> > +sleep-intput-disable - disable input on pin when the specified system goes
> > + into deep sleep mode (no effect on output)
> > +sleep-output-low - set the pin to output mode with low level when the
> > + specified system goes into deep sleep mode
> > +sleep-output-high - set the pin to output mode with high level when the
> > + specified system goes into deep sleep mode
> > slew-rate - set the slew rate
>
> I don't really like having 2 ways to define pin setup and this doesn't
> scale if I need to define 3 states. Couldn't we create pin state
> definitions and have a pinctrl-n property within the pin controller
> node to handle all the unhandled pins?

As LinusW also suggest we can create one "sleep" state and program them
into registers at early point (like: after probing pinctrl driver). So I
think I can introduce one called "early-sleep" state which need select it
after initializing pinctrl driver.

>
> Rob