linux-kernel - Re: [PATCH] eint: add gpio vritual number select

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Message-ID: <1545044969.15380.1.camel@mhfsdcap03>
Date:   Mon, 17 Dec 2018 19:09:29 +0800
From:   Chuanjia Liu <Chuanjia.Liu@...iatek.com>
To:     Sean Wang <sean.wang@...nel.org>
CC:     Linus Walleij <linus.walleij@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <hongkun.cao@...iatek.com>,
        <youlin.pei@...iatek.com>, <eddie.huang@...iatek.com>,
        <zhiyong.tao@...iatek.com>, <hailong.fan@...iatek.com>
Subject: Re: [PATCH] eint: add gpio vritual number select

On Sun, 2018-12-16 at 23:59 -0800, Sean Wang wrote:
> On Sun, Dec 16, 2018 at 7:15 PM Chuanjia Liu <Chuanjia.Liu@...iatek.com> wrote:
> >
> > On Thu, 2018-12-13 at 11:33 -0800, Sean Wang wrote:
> > > On Thu, Dec 13, 2018 at 1:36 AM <chuanjia.liu@...iatek.com> wrote:
> > > >
> > > > From: Chuanjia Liu <Chuanjia.Liu@...iatek.com>
> > > >
> > > > This patch add gpio vritual number select,avoid virtual gpio set SMT.
> > >
> > > s/gpio/GPIO/
> > > s/vritual/virtual/
> > >
> > > Virtual GPIOs you said here that means these pins only used inside SoC
> > > and not being exported to outside SoC, right? It seems this kind of
> > > pins doesn't need SMT.
> > >
> > Yes,virtual gpio only used inside SOC and these pins doesn't need set
> > SMT
> > > >
> > > > Signed-off-by: Chuanjia Liu <Chuanjia.Liu@...iatek.com>
> > > > ---
> > > >  drivers/pinctrl/mediatek/mtk-eint.h              |    1 +
> > > >  drivers/pinctrl/mediatek/pinctrl-mt8183.c        |    1 +
> > > >  drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c |    9 ++++++---
> > > >  3 files changed, 8 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/drivers/pinctrl/mediatek/mtk-eint.h b/drivers/pinctrl/mediatek/mtk-eint.h
> > > > index 48468d0..c16beaf 100644
> > > > --- a/drivers/pinctrl/mediatek/mtk-eint.h
> > > > +++ b/drivers/pinctrl/mediatek/mtk-eint.h
> > > > @@ -37,6 +37,7 @@ struct mtk_eint_hw {
> > > >         u8              ports;
> > > >         unsigned int    ap_num;
> > > >         unsigned int    db_cnt;
> > > > +       unsigned int    vir_start;
> > > >  };
> > > >
> > > >  struct mtk_eint;
> > > > diff --git a/drivers/pinctrl/mediatek/pinctrl-mt8183.c b/drivers/pinctrl/mediatek/pinctrl-mt8183.c
> > > > index 6262fd3..bbeafd3 100644
> > > > --- a/drivers/pinctrl/mediatek/pinctrl-mt8183.c
> > > > +++ b/drivers/pinctrl/mediatek/pinctrl-mt8183.c
> > > > @@ -497,6 +497,7 @@
> > > >         .ports     = 6,
> > > >         .ap_num    = 212,
> > > >         .db_cnt    = 13,
> > > > +       .vir_start = 180,
> > > >  };
> > > >
> > > >  static const struct mtk_pin_soc mt8183_data = {
> > > > diff --git a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> > > > index 4a9e0d4..ca3bae1 100644
> > > > --- a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> > > > +++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> > > > @@ -289,9 +289,12 @@ static int mtk_xt_set_gpio_as_eint(void *data, unsigned long eint_n)
> > > >         if (err)
> > > >                 return err;
> > > >
> > > > -       err = mtk_hw_set_value(hw, desc, PINCTRL_PIN_REG_SMT, MTK_ENABLE);
> > > > -       if (err)
> > > > -               return err;
> > > > +       if (gpio_n < hw->eint->hw->vir_start) {
> > > > +               err = mtk_hw_set_value(hw, desc, PINCTRL_PIN_REG_SMT,
> > > > +                                      MTK_ENABLE);
> > > > +               if (err)
> > > > +                       return err;
> > > > +       }
> > >
> > > The changes will break these SoCs without a properly configured vir_start.
> > >
> > > If SMT seems unnecessary for these kinds of virtual GPIOs pin in the
> > > path, we can do it as
> > >
> > > err = mtk_hw_set_value(hw, desc, PINCTRL_PIN_REG_SMT,
> > >                                         MTK_ENABLE);
> > > /* please add comments for the exclusion condition */
> > > if (err && err != -ENOTSUPP)
> > >         return err;
> > >
> > > If there is getting much special on certain pins between SoCs, and
> > > then we can consider creating a desc->flag to split logic.
> >
> > Yes,SMT unnecessary for these kinds of virtual GPIOS pin in the path,if
> > do it as
> >         err = mtk_hw_set_value(hw, desc, PINCTRL_PIN_REG_SMT,
> >                                         MTK_ENABLE);
> >         if (err && err != -ENOTSUPP)
> >                   return err;
> > I wonder if system will lose -ENOTSUPP information when smt was not
> > successfully set by real gpio?
> 
> -ENOTSUPP shouldn't happen in a real pin as SMT is supposed to be
> supported by every real pin.
> 
> If it is not true or there are more special on certain pins, and then
> we consider to add a flag to struct mtk_pin_desc to group these pins
> with their characteristics and to split and reuse the common code flow
> with the extra flag.
> 
> So for now, I thought it's enough to handle your case with adding a
> few well self-explained comments for the exclusion condition. These
> words help us remember we should add adding an extra flag to pin
> description as one of TODO if more needs like you come out.
> 
 Thanks for your advice,I will update new patch
> > >
> > > >
> > > >         return 0;
> > > >  }
> > > > --
> > > > 1.7.9.5
> >
> >