[PATCH 1/1] UBUNTU: SAUCE: i2c: designware: Add disable runtime pm quirk

[AceLan Kao]

It's still necessary to prevent it from calling pm_runtime_get/put explicitly,
The "put" function still make designware enter runtime suspended, so
but "get" can't wake it up,
and then it leads to strange issue that it complains it can't wake up
the dw and the i2c command times out.

Kai-Heng Feng <kai.heng.feng at canonical.com> 於 2019年6月20日 週四 下午1:04寫道：
>
> at 10:38, AceLan Kao <acelan.kao at canonical.com> wrote:
>
> > BugLink: https://bugs.launchpad.net/bugs/1833484
> >
> > Dell machines come with goodix touchpad IC suffer from the double click
> > issue if the Designware I2C adapter enters runtime suspend.
> >
> > It's because the goodix re-assert the interrupt if host doesn't read the
> > data within 100ms and desiginware takes a longer time to wake up from
> > runtime suspend. In the case, it got a second interrupt during
> > resuming, so it thinks it's a double click.
> >
> > There is no simple way to fix this, it's a firmware issue and goodix
> > agrees to fix this in their firmware on next release, but this issue is
> > still affects the machines that don't come with an updated firmware. So,
> > add a quirk to mark those machines and avoid the designware to enter
> > runtime suspend.
> >
> > Signed-off-by: AceLan Kao <acelan.kao at canonical.com>
> > ---
> >  drivers/i2c/busses/i2c-designware-master.c | 30 ++++++++++++++++++++--
> >  1 file changed, 28 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-designware-master.c
> > b/drivers/i2c/busses/i2c-designware-master.c
> > index bb8e3f149979..7acb015f0470 100644
> > --- a/drivers/i2c/busses/i2c-designware-master.c
> > +++ b/drivers/i2c/busses/i2c-designware-master.c
> > @@ -9,6 +9,7 @@
> >   * Copyright (C) 2009 Provigent Ltd.
> >   */
> >  #include <linux/delay.h>
> > +#include <linux/dmi.h>
> >  #include <linux/err.h>
> >  #include <linux/errno.h>
> >  #include <linux/export.h>
> > @@ -22,6 +23,25 @@
> >
> >  #include "i2c-designware-core.h"
> >
> > +static int no_runtime_pm;
> > +static const struct dmi_system_id i2c_dw_no_runtime_pm[] = {
> > +     {
> > +             .ident = "Dell Vostro 5390",
> > +             .matches = {
> > +                     DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> > +                     DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 5390"),
> > +             },
> > +     },
> > +     {
> > +             .ident = "Dell Vostro 5391",
> > +             .matches = {
> > +                     DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> > +                     DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 5391"),
> > +             },
> > +     },
> > +     { }
> > +};
> > +
> >  static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev)
> >  {
> >       /* Configure Tx/Rx FIFO threshold levels */
> > @@ -424,7 +444,8 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg
> > msgs[], int num)
> >
> >       dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
> >
> > -     pm_runtime_get_sync(dev->dev);
> > +     if (!no_runtime_pm)
> > +             pm_runtime_get_sync(dev->dev);
> >
> >       if (dev->suspended) {
> >               dev_err(dev->dev, "Error %s call while suspended\n", __func__);
> > @@ -502,7 +523,8 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg
> > msgs[], int num)
> >
> >  done_nolock:
> >       pm_runtime_mark_last_busy(dev->dev);
> > -     pm_runtime_put_autosuspend(dev->dev);
> > +     if (!no_runtime_pm)
> > +             pm_runtime_put_autosuspend(dev->dev);
> >
> >       return ret;
> >  }
> > @@ -734,6 +756,10 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
> >       if (ret)
> >               return ret;
> >
> > +     no_runtime_pm = dmi_check_system(i2c_dw_no_runtime_pm);
> > +     if (no_runtime_pm)
> > +             __pm_runtime_disable(dev->dev, true);
> > +
>
> I think using pm helpers in i2c_dw_xfer() is unnecessary if we do this in
> i2c_dw_probe():
>
> --- a/drivers/i2c/busses/i2c-designware-master.c
> +++ b/drivers/i2c/busses/i2c-designware-master.c
> @@ -743,7 +743,9 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
>          ret = i2c_add_numbered_adapter(adap);
>          if (ret)
>                  dev_err(dev->dev, "failure adding adapter: %d\n", ret);
> -       pm_runtime_put_noidle(dev->dev);
> +
> +       if (!no_runtime_pm)
> +               pm_runtime_put_noidle(dev->dev);
>
>          return ret;
>   }
>
>
> >       /*
> >        * Increment PM usage count during adapter registration in order to
> >        * avoid possible spurious runtime suspend when adapter device is
> > --
> > 2.17.1
> >
> >
> > --
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> > kernel-team at lists.ubuntu.com
> > https://lists.ubuntu.com/mailman/listinfo/kernel-team
>
>