Re: [PATCH 01/14] power: reset: at91-poweroff: Stop using module_platform_driver_probe()

From: claudiu beznea <claudiu.beznea@tuxon.dev>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Sebastian Reichel" <sre@kernel.org>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>,
	linux-kbuild@vger.kernel.org, linux-pm@vger.kernel.org,
	kernel@pengutronix.de, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 01/14] power: reset: at91-poweroff: Stop using module_platform_driver_probe()
Date: Wed, 8 Nov 2023 08:54:23 +0200	[thread overview]
Message-ID: <ffeacb49-53ee-4b30-9e79-ef5490eeec98@tuxon.dev> (raw)
In-Reply-To: <20231104211501.3676352-17-u.kleine-koenig@pengutronix.de>


On 04.11.2023 23:15, Uwe Kleine-König wrote:
> On today's platforms the benefit of platform_driver_probe() isn't that
> relevant any more. It allows to drop some code after booting (or module
> loading) for .probe() and discard the .remove() function completely if
> the driver is built-in. This typically saves a few 100k.
> 
> The downside of platform_driver_probe() is that the driver cannot be
> bound and unbound at runtime which is ancient and so slightly
> complicates testing. There are also thoughts to deprecate
> platform_driver_probe() because it adds some complexity in the driver
> core for little gain. Also many drivers don't use it correctly. This
> driver for example misses to mark the driver struct with __ref which is
> needed to suppress a (W=1) modpost warning.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>

> ---
>  drivers/power/reset/at91-poweroff.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/power/reset/at91-poweroff.c b/drivers/power/reset/at91-poweroff.c
> index dd5399785b69..83567428ab43 100644
> --- a/drivers/power/reset/at91-poweroff.c
> +++ b/drivers/power/reset/at91-poweroff.c
> @@ -149,7 +149,7 @@ static void at91_poweroff_dt_set_wakeup_mode(struct platform_device *pdev)
>  	writel(wakeup_mode | mode, at91_shdwc.shdwc_base + AT91_SHDW_MR);
>  }
>  
> -static int __init at91_poweroff_probe(struct platform_device *pdev)
> +static int at91_poweroff_probe(struct platform_device *pdev)
>  {
>  	struct device_node *np;
>  	u32 ddr_type;
> @@ -202,7 +202,7 @@ static int __init at91_poweroff_probe(struct platform_device *pdev)
>  	return ret;
>  }
>  
> -static int __exit at91_poweroff_remove(struct platform_device *pdev)
> +static int at91_poweroff_remove(struct platform_device *pdev)
>  {
>  	if (pm_power_off == at91_poweroff)
>  		pm_power_off = NULL;
> @@ -224,13 +224,14 @@ static const struct of_device_id at91_poweroff_of_match[] = {
>  MODULE_DEVICE_TABLE(of, at91_poweroff_of_match);
>  
>  static struct platform_driver at91_poweroff_driver = {
> -	.remove = __exit_p(at91_poweroff_remove),
> +	.probe = at91_poweroff_probe,
> +	.remove = at91_poweroff_remove,
>  	.driver = {
>  		.name = "at91-poweroff",
>  		.of_match_table = at91_poweroff_of_match,
>  	},
>  };
> -module_platform_driver_probe(at91_poweroff_driver, at91_poweroff_probe);
> +module_platform_driver(at91_poweroff_driver);
>  
>  MODULE_AUTHOR("Atmel Corporation");
>  MODULE_DESCRIPTION("Shutdown driver for Atmel SoCs");

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