linux-kernel - Re: [PATCH v4 0/3] gpio: gpio-regmap: Support few custom operations

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Date:   Wed, 26 May 2021 11:42:11 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc:     Matti Vaittinen <mazziesaccount@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Michael Walle <michael@...le.cc>,
        Florian Fainelli <f.fainelli@...il.com>,
        bcm-kernel-feedback-list <bcm-kernel-feedback-list@...adcom.com>,
        Jonas Gorski <jonas.gorski@...il.com>,
        Álvaro Fernández Rojas <noltari@...il.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-power <linux-power@...rohmeurope.com>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v4 0/3] gpio: gpio-regmap: Support few custom operations

On Wed, May 26, 2021 at 9:02 AM Matti Vaittinen
<matti.vaittinen@...rohmeurope.com> wrote:
>
> Support providing some IC specific operations at gpio_regmap registration.
>
> Implementation of few GPIO related functionalities are likely to be
> very IC specific. For example the pin-configuration registers and the
> pin validity checks. Allow IC driver to provide IC specific functions
> which gpio-regmap can utilize for these IC specific configurations.
> This should help broaden the gpio-regmap IC coverage without the need
> of exposing the registered gpio_chip or struct gpio_regmap to IC drivers.
>
> The set_config and init_valid_mask are used by ROHM BD71815 GPIO driver.
> Convert the BD71815 GPIO driver to use gpio-regmap and get rid of some
> code. Rest of the ROHM GPIO drivers are to be reworked after the
> mechanism of adding IC specific functions is settled.
>
> Some preliminary discussion can be seen here:
> https://lore.kernel.org/linux-gpio/c4faac648d3e0c7f3dcb50f7e24c8b322e8c6974.camel@fi.rohmeurope.com/
>
> I did also prepare change where the getters for drvdata and regmap
> are used. It can also work - but it does not scale quite as well
> if (when) IC drivers need some register information to do custom
> operations. Interested people can see the:
> https://github.com/M-Vaittinen/linux/commits/gpio-regmap-getters
> for comparison.

Entire series looks good to me,
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>

> Changelog v4:
>  - Convert also the existing users.
>
> Changelog v3:
>  - divide gpio_regmap into private part and part which contains
>    user-visible configurations. This should allow keeping the internal
>    data internal to gpio_regmap - while allowing the IC driver to re-use
>    configurations it has provided to gpio-regmap without a need of
>    storing them to private-data. Furthermore avoid implementing dummy
>    'getter-functions' for regmap, driver-data, register details,
>    firmware node etc.
>  - change devm_add_action() to devm_add_action_or_reset()
>  - the bd71815 GPIO driver, completely drop private-data.
>
> Changelog v2:
>  - Add cover-letter
>  - Drop unnecessary checks for callback function validity
>  - drop driver_data setting function as it is likely to be a
>    race-condition-by-design
>
> ---
>
> Matti Vaittinen (3):
>   gpio: regmap: Support few IC specific operations
>   gpio: gpio-regmap: Use devm_add_action_or_reset()
>   gpio: bd71815: Use gpio-regmap
>
>  drivers/gpio/Kconfig                  |   1 +
>  drivers/gpio/gpio-bd71815.c           | 121 ++++-----------
>  drivers/gpio/gpio-regmap.c            | 212 +++++++++++++++-----------
>  drivers/gpio/gpio-sl28cpld.c          |   3 +-
>  drivers/pinctrl/bcm/pinctrl-bcm63xx.c |   8 +-
>  include/linux/gpio/regmap.h           |  51 +++++--
>  6 files changed, 194 insertions(+), 202 deletions(-)
>
>
> base-commit: c4681547bcce777daf576925a966ffa824edd09d
> --
> 2.25.4
>
>
> --
> Matti Vaittinen, Linux device drivers
> ROHM Semiconductors, Finland SWDC
> Kiviharjunlenkki 1E
> 90220 OULU
> FINLAND
>
> ~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
> Simon says - in Latin please.
> ~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
> Thanks to Simon Glass for the translation =]



-- 
With Best Regards,
Andy Shevchenko