Re: [PATCH v4 02/11] firmware: raspberrypi: Introduce devm_rpi_firmware_get()

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
To: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	"Florian Fainelli" <f.fainelli@gmail.com>,
	"Ray Jui" <rjui@broadcom.com>,
	"Scott Branden" <sbranden@broadcom.com>,
	bcm-kernel-feedback-list@broadcom.com, linux-pwm@vger.kernel.org,
	arm-soc <linux-arm-kernel@lists.infradead.org>,
	linux-devicetree <devicetree@vger.kernel.org>,
	wahrenst@gmx.net, "Linux Input" <linux-input@vger.kernel.org>,
	"Dmitry Torokhov" <dmitry.torokhov@gmail.com>,
	"Greg KH" <gregkh@linuxfoundation.org>,
	devel@driverdev.osuosl.org,
	"Philipp Zabel" <p.zabel@pengutronix.de>,
	linux-gpio <linux-gpio@vger.kernel.org>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	"Stephen Boyd" <sboyd@kernel.org>,
	linux-rpi-kernel@lists.infradead.org,
	"Andy Shevchenko" <andy.shevchenko@gmail.com>
Subject: Re: [PATCH v4 02/11] firmware: raspberrypi: Introduce devm_rpi_firmware_get()
Date: Thu, 12 Nov 2020 18:25:46 +0100	[thread overview]
Message-ID: <CAMpxmJWZsqfkkTP99a_8mu+O4xHwNWDqHuvgt7Cs88bA-iMvQA@mail.gmail.com> (raw)
In-Reply-To: <20201112163630.17177-3-nsaenzjulienne@suse.de>

On Thu, Nov 12, 2020 at 5:44 PM Nicolas Saenz Julienne
<nsaenzjulienne@suse.de> wrote:
>
> Itroduce devm_rpi_firmware_get(), it'll simplify the firmware handling
> for most consumers.
>
> Suggested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> ---
>
> Changes since v2:
> - Introduce devm_rpi_firmware_get()
>
>  drivers/firmware/raspberrypi.c             | 31 +++++++++++++++++++++-
>  include/soc/bcm2835/raspberrypi-firmware.h |  8 ++++++
>  2 files changed, 38 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
> index 438e17074a97..4ab2dfdc82ad 100644
> --- a/drivers/firmware/raspberrypi.c
> +++ b/drivers/firmware/raspberrypi.c
> @@ -237,10 +237,17 @@ static void rpi_firmware_delete(struct kref *kref)
>         kfree(fw);
>  }
>
> -void rpi_firmware_put(struct rpi_firmware *fw)
> +static void __rpi_firmware_put(void *data)
>  {

The '__' prefix is very vague and usually used for unlocked variants
of functions. The casting to void * in rpi_firmware_put() is also
unneeded. I would much prefer that the devres release callback be
called devm_rpi_firmware_put() and that it call rpi_firmware_put()
which would then call kref_put().

Bartosz

> +       struct rpi_firmware *fw = data;
> +
>         kref_put(&fw->consumers, rpi_firmware_delete);
>  }
> +
> +void rpi_firmware_put(struct rpi_firmware *fw)
> +{
> +       __rpi_firmware_put(fw);
> +}
>  EXPORT_SYMBOL_GPL(rpi_firmware_put);
>
>  static int rpi_firmware_probe(struct platform_device *pdev)
> @@ -326,6 +333,28 @@ struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
>  }
>  EXPORT_SYMBOL_GPL(rpi_firmware_get);
>
> +/**
> + * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
> + * @firmware_node:    Pointer to the firmware Device Tree node.
> + *
> + * Returns NULL is the firmware device is not ready.
> + */
> +struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
> +                                          struct device_node *firmware_node)
> +{
> +       struct rpi_firmware *fw;
> +
> +       fw = rpi_firmware_get(firmware_node);
> +       if (!fw)
> +               return NULL;
> +
> +       if (devm_add_action_or_reset(dev, __rpi_firmware_put, fw))
> +               return NULL;
> +
> +       return fw;
> +}
> +EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
> +
>  static const struct of_device_id rpi_firmware_of_match[] = {
>         { .compatible = "raspberrypi,bcm2835-firmware", },
>         {},
> diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
> index fdfef7fe40df..73ad784fca96 100644
> --- a/include/soc/bcm2835/raspberrypi-firmware.h
> +++ b/include/soc/bcm2835/raspberrypi-firmware.h
> @@ -142,6 +142,8 @@ int rpi_firmware_property_list(struct rpi_firmware *fw,
>                                void *data, size_t tag_size);
>  void rpi_firmware_put(struct rpi_firmware *fw);
>  struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node);
> +struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
> +                                          struct device_node *firmware_node);
>  #else
>  static inline int rpi_firmware_property(struct rpi_firmware *fw, u32 tag,
>                                         void *data, size_t len)
> @@ -160,6 +162,12 @@ static inline struct rpi_firmware *rpi_firmware_get(struct device_node *firmware
>  {
>         return NULL;
>  }
> +
> +static inline struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
> +                                       struct device_node *firmware_node)
> +{
> +       return NULL;
> +}
>  #endif
>
>  #endif /* __SOC_RASPBERRY_FIRMWARE_H__ */
> --
> 2.29.2
>