[U-Boot] [PATCH v3 2/2] gpio: dwapb_gpio: Add reset ctrl to driver

[Ley Foon Tan]

On Tue, Aug 28, 2018 at 5:53 PM Marek Vasut <marex at denx.de> wrote:
>
> On 08/28/2018 06:07 PM, Ley Foon Tan wrote:
> > Add code to reset all reset signals as in gpio DT node. A reset property
> > is an optional feature, so only print out a warning and do not fail if a
> > reset property is not present.
> >
> > If a reset property is discovered, then use it to deassert, thus
> > bringing the IP out of reset.
> >
> > Signed-off-by: Ley Foon Tan <ley.foon.tan at intel.com>
> >
> > ---
> > v3:
> > - Add .remove function.
> > - Add error handling when return non-zero from reset_get_bulk().
> >
> > v2:
> > - Move reset to probe() function.
> > ---
> >  drivers/gpio/dwapb_gpio.c |   42 ++++++++++++++++++++++++++++++++++++++++--
> >  1 files changed, 40 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpio/dwapb_gpio.c b/drivers/gpio/dwapb_gpio.c
> > index 7cf2d47..6394fa9 100644
> > --- a/drivers/gpio/dwapb_gpio.c
> > +++ b/drivers/gpio/dwapb_gpio.c
> > @@ -15,6 +15,7 @@
> >  #include <dm/lists.h>
> >  #include <dm/root.h>
> >  #include <errno.h>
> > +#include <reset.h>
> >
> >  DECLARE_GLOBAL_DATA_PTR;
> >
> > @@ -99,13 +100,42 @@ static const struct dm_gpio_ops gpio_dwapb_ops = {
> >       .get_function           = dwapb_gpio_get_function,
> >  };
> >
> > +static int gpio_dwapb_reset(struct udevice *dev)
> > +{
> > +     int ret;
> > +     struct gpio_dev_priv *priv = dev_get_uclass_priv(dev);
> > +
> > +     ret = reset_get_bulk(dev, &priv->resets);
> > +     if (ret) {
> > +             dev_warn(dev, "Can't get reset: %d\n", ret);
> > +             /* Return 0 if error due to !CONFIG_DM_RESET and reset
> > +              * DT property is not present.
> > +              */
> > +             if (ret == -ENOENT || ret == -ENOTSUPP)
> > +                     return 0;
> > +             else
> > +                     return ret;
> > +     }
> > +
> > +     ret = reset_deassert_bulk(&priv->resets);
> > +     if (ret) {
> > +             reset_release_bulk(&priv->resets);
> > +             dev_err(dev, "Failed to reset: %d\n", ret);
> > +             return ret;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> >  static int gpio_dwapb_probe(struct udevice *dev)
> >  {
> >       struct gpio_dev_priv *priv = dev_get_uclass_priv(dev);
> >       struct gpio_dwapb_platdata *plat = dev->platdata;
> >
> > -     if (!plat)
> > -             return 0;
> > +     if (!plat) {
> > +             /* Reset on parent device only */
> > +             return gpio_dwapb_reset(dev);
> > +     }
> >
> >       priv->gpio_count = plat->pins;
> >       priv->bank_name = plat->name;
> > @@ -166,6 +196,13 @@ err:
> >       return ret;
> >  }
> >
> > +static int gpio_dwapb_remove(struct udevice *dev)
> > +{
> > +     struct gpio_dev_priv *priv = dev_get_uclass_priv(dev);
>
> You might want to assert the reset too.

reset_release_bulk() function will assert the reset and free reset struct.

>
> > +     return reset_release_bulk(&priv->resets);
> > +}
> > +
> >  static const struct udevice_id gpio_dwapb_ids[] = {
> >       { .compatible = "snps,dw-apb-gpio" },
> >       { }
> > @@ -178,4 +215,5 @@ U_BOOT_DRIVER(gpio_dwapb) = {
> >       .ops            = &gpio_dwapb_ops,
> >       .bind           = gpio_dwapb_bind,
> >       .probe          = gpio_dwapb_probe,
> > +     .remove         = gpio_dwapb_remove,
> >  };
> >
>
>
Regards
Ley Foon