linux-kernel - Re: [PATCH v10 5/7] i2c: of-prober: Add GPIO support to simple helpers

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Message-ID: <CAGXv+5E5izmR0Oe8RK8eGRxV4vk+98yKJDMc5imgSznxPZp01Q@mail.gmail.com>
Date: Wed, 6 Nov 2024 16:12:30 +0800
From: Chen-Yu Tsai <wenst@...omium.org>
To: Andrey Skvortsov <andrej.skvortzov@...il.com>, Chen-Yu Tsai <wenst@...omium.org>, 
	Rob Herring <robh@...nel.org>, Saravana Kannan <saravanak@...gle.com>, 
	Matthias Brugger <matthias.bgg@...il.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, Wolfram Sang <wsa@...nel.org>, 
	Benson Leung <bleung@...omium.org>, Tzung-Bi Shih <tzungbi@...nel.org>, 
	chrome-platform@...ts.linux.dev, devicetree@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, Douglas Anderson <dianders@...omium.org>, 
	Johan Hovold <johan@...nel.org>, Jiri Kosina <jikos@...nel.org>, 
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, linux-i2c@...r.kernel.org
Subject: Re: [PATCH v10 5/7] i2c: of-prober: Add GPIO support to simple helpers

On Wed, Nov 6, 2024 at 12:14 AM Andrey Skvortsov
<andrej.skvortzov@...il.com> wrote:
>
> On 24-10-30 15:22, Chen-Yu Tsai wrote:
> > Add GPIO support to the simple helpers for the I2C OF component prober.
> > Components that the prober intends to probe likely require their
> > regulator supplies be enabled, and GPIOs be toggled to enable them or
> > bring them out of reset before they will respond to probe attempts.
> > Regulator supplies were handled in the previous patch.
> >
> > The assumption is that the same class of components to be probed are
> > always connected in the same fashion with the same regulator supply
> > and GPIO. The names may vary due to binding differences, but the
> > physical layout does not change.
> >
> > This supports at most one GPIO pin. The user must specify the GPIO name,
> > the polarity, and the amount of time to wait after the GPIO is toggled.
> > Devices with more than one GPIO pin likely require specific power
> > sequencing beyond what generic code can easily support.
> >
> > Signed-off-by: Chen-Yu Tsai <wenst@...omium.org>
> > Reviewed-by: Douglas Anderson <dianders@...omium.org>
> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > ---
>
> > diff --git a/include/linux/i2c-of-prober.h b/include/linux/i2c-of-prober.h
> > index df95aa6ad90e..a232f3cbb252 100644
> > --- a/include/linux/i2c-of-prober.h
> > +++ b/include/linux/i2c-of-prober.h
> > @@ -85,6 +85,7 @@ int i2c_of_probe_component(struct device *dev, const struct i2c_of_probe_cfg *cf
> >   *
> >   * The following helpers are provided:
> >   * * i2c_of_probe_simple_enable()
> > + * * i2c_of_probe_simple_cleanup_early()
> >   * * i2c_of_probe_simple_cleanup()
> >   */
> >
> > @@ -92,14 +93,31 @@ int i2c_of_probe_component(struct device *dev, const struct i2c_of_probe_cfg *cf
> >   * struct i2c_of_probe_simple_opts - Options for simple I2C component prober callbacks
> >   * @res_node_compatible: Compatible string of device node to retrieve resources from.
> >   * @supply_name: Name of regulator supply.
> > + * @gpio_name: Name of GPIO. NULL if no GPIO line is used. Empty string ("") if GPIO
> > + *          line is unnamed.
> >   * @post_power_on_delay_ms: Delay after regulators are powered on. Passed to msleep().
> > + * @post_gpio_config_delay_ms: Delay after GPIO is configured. Passed to msleep().
> > + * @gpio_assert_to_enable: %true if GPIO should be asserted, i.e. set to logical high,
> > + *                      to enable the component.
> > + *
> > + * This describes power sequences common for the class of components supported by the
> > + * simple component prober:
> > + * * @gpio_name is configured to the non-active setting according to @gpio_assert_to_enable.
> > + * * @supply_name regulator supply is enabled.
> > + * * Wait for @post_power_on_delay_ms to pass.
> > + * * @gpio_name is configured to the active setting according to @gpio_assert_to_enable.
> > + * * Wait for @post_gpio_config_delay_ms to pass.
> >   */
> >  struct i2c_of_probe_simple_opts {
> >       const char *res_node_compatible;
> >       const char *supply_name;
> > +     const char *gpio_name;
> >       unsigned int post_power_on_delay_ms;
> > +     unsigned int post_gpio_config_delay_ms;
> > +     bool gpio_assert_to_enable;
>
> This header is missing '#include <linux/types.h>' for bool
> type. Otherwise compilation may fail with following error:
>
> ```
> ./include/linux/i2c-of-prober.h:117:9: error: unknown type name ‘bool’
>   117 |         bool gpio_assert_to_enable;
>       |         ^~~~
> ./include/linux/i2c-of-prober.h:12:1: note: ‘bool’ is defined in header ‘<stdbool.h>’; this is probably fixable by adding ‘#include <stdbool.h>’
>    11 | #include <linux/kconfig.h>
>   +++ |+#include <stdbool.h>
>    12 |
> ```

Thanks for catching this.

I'll send an update.

> >  };
> >
> > +struct gpio_desc;
> >  struct regulator;
> >
> >  struct i2c_of_probe_simple_ctx {
> > @@ -107,9 +125,11 @@ struct i2c_of_probe_simple_ctx {
> >       const struct i2c_of_probe_simple_opts *opts;
> >       /* private: internal fields for helpers. */
> >       struct regulator *supply;
> > +     struct gpio_desc *gpiod;
> >  };
> >
> >  int i2c_of_probe_simple_enable(struct device *dev, struct device_node *bus_node, void *data);
> > +void i2c_of_probe_simple_cleanup_early(struct device *dev, void *data);
> >  void i2c_of_probe_simple_cleanup(struct device *dev, void *data);
> >
> >  extern struct i2c_of_probe_ops i2c_of_probe_simple_ops;
> > --
> > 2.47.0.163.g1226f6d8fa-goog
> >
>
> --
> Best regards,
> Andrey Skvortsov