linux-kernel - Re: [PATCH v2 03/10] leds: aw2013: use devm API to cleanup module's resources

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Date:   Mon, 4 Dec 2023 23:14:31 +0000
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     George Stark <gnstark@...utedevices.com>,
        "pavel@....cz" <pavel@....cz>, "lee@...nel.org" <lee@...nel.org>,
        "vadimp@...dia.com" <vadimp@...dia.com>,
        "mpe@...erman.id.au" <mpe@...erman.id.au>,
        "npiggin@...il.com" <npiggin@...il.com>,
        "hdegoede@...hat.com" <hdegoede@...hat.com>,
        "mazziesaccount@...il.com" <mazziesaccount@...il.com>,
        "andy.shevchenko@...il.com" <andy.shevchenko@...il.com>,
        "jic23@...nel.org" <jic23@...nel.org>
CC:     "linux-leds@...r.kernel.org" <linux-leds@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "kernel@...utedevices.com" <kernel@...utedevices.com>
Subject: Re: [PATCH v2 03/10] leds: aw2013: use devm API to cleanup module's
 resources



Le 04/12/2023 à 19:05, George Stark a écrit :
> In this driver LEDs are registered using devm_led_classdev_register()
> so they are automatically unregistered after module's remove() is done.
> led_classdev_unregister() calls module's led_set_brightness() to turn off
> the LEDs and that callback uses resources which were destroyed already
> in module's remove() so use devm API instead of remove().
> 
> Signed-off-by: George Stark <gnstark@...utedevices.com>
> ---
>   drivers/leds/leds-aw2013.c | 27 +++++++++++++++------------
>   1 file changed, 15 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/leds/leds-aw2013.c b/drivers/leds/leds-aw2013.c
> index c2bc0782c0cd..1a8acf303548 100644
> --- a/drivers/leds/leds-aw2013.c
> +++ b/drivers/leds/leds-aw2013.c
> @@ -1,6 +1,7 @@
>   // SPDX-License-Identifier: GPL-2.0+
>   // Driver for Awinic AW2013 3-channel LED driver
>   
> +#include <linux/devm-helpers.h>
>   #include <linux/i2c.h>
>   #include <linux/leds.h>
>   #include <linux/module.h>
> @@ -318,6 +319,13 @@ static int aw2013_probe_dt(struct aw2013 *chip)
>   	return 0;
>   }
>   
> +static void aw2013_chip_disable_action(void *data)
> +{
> +	struct aw2013 *chip = (struct aw2013 *)data;

The cast is not needed because data is void*

And chip is not needed at all, you can pass data to 
aw2013_chip_disable() directly, without a cast either.

> +
> +	aw2013_chip_disable(chip);
> +}
> +
>   static const struct regmap_config aw2013_regmap_config = {
>   	.reg_bits = 8,
>   	.val_bits = 8,
> @@ -334,7 +342,9 @@ static int aw2013_probe(struct i2c_client *client)
>   	if (!chip)
>   		return -ENOMEM;
>   
> -	mutex_init(&chip->mutex);
> +	if (devm_mutex_init(&client->dev, &chip->mutex))
> +		return -ENOMEM;

Why not return the value returned by devm_mutex_init() ?

> +
>   	mutex_lock(&chip->mutex);
>   
>   	chip->client = client;
> @@ -378,6 +388,10 @@ static int aw2013_probe(struct i2c_client *client)
>   		goto error_reg;
>   	}
>   
> +	ret = devm_add_action(&client->dev, aw2013_chip_disable_action, chip);
> +	if (ret)
> +		goto error_reg;
> +
>   	ret = aw2013_probe_dt(chip);
>   	if (ret < 0)
>   		goto error_reg;
> @@ -398,19 +412,9 @@ static int aw2013_probe(struct i2c_client *client)
>   
>   error:
>   	mutex_unlock(&chip->mutex);
> -	mutex_destroy(&chip->mutex);
>   	return ret;
>   }
>   
> -static void aw2013_remove(struct i2c_client *client)
> -{
> -	struct aw2013 *chip = i2c_get_clientdata(client);
> -
> -	aw2013_chip_disable(chip);
> -
> -	mutex_destroy(&chip->mutex);
> -}
> -
>   static const struct of_device_id aw2013_match_table[] = {
>   	{ .compatible = "awinic,aw2013", },
>   	{ /* sentinel */ },
> @@ -424,7 +428,6 @@ static struct i2c_driver aw2013_driver = {
>   		.of_match_table = of_match_ptr(aw2013_match_table),
>   	},
>   	.probe = aw2013_probe,
> -	.remove = aw2013_remove,
>   };
>   
>   module_i2c_driver(aw2013_driver);