linux-kernel - Re: [PATCH v2 04/10] leds: aw200xx: use devm API to cleanup module's resources

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Message-ID: <afd07c38-b490-4498-aa12-219fec8c39c9@csgroup.eu>
Date:   Mon, 4 Dec 2023 23:17:55 +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 04/10] leds: aw200xx: 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-aw200xx.c | 36 +++++++++++++++++++++++++-----------
>   1 file changed, 25 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/leds/leds-aw200xx.c b/drivers/leds/leds-aw200xx.c
> index 1d3943f86f7f..b1a097c7c879 100644
> --- a/drivers/leds/leds-aw200xx.c
> +++ b/drivers/leds/leds-aw200xx.c
> @@ -10,6 +10,7 @@
>   #include <linux/bitfield.h>
>   #include <linux/bits.h>
>   #include <linux/container_of.h>
> +#include <linux/devm-helpers.h>
>   #include <linux/gpio/consumer.h>
>   #include <linux/i2c.h>
>   #include <linux/leds.h>
> @@ -530,6 +531,20 @@ static const struct regmap_config aw200xx_regmap_config = {
>   	.disable_locking = true,
>   };
>   
> +static void aw200xx_chip_reset_action(void *data)
> +{
> +	const struct aw200xx *chip = (struct aw200xx *)data;
> +
> +	aw200xx_chip_reset(chip);

Same as previous patch, no need to cast data and no need for chip at 
all, directly do aw200xx_chip_reset(data)

> +}
> +
> +static void aw200xx_disable_action(void *data)
> +{
> +	const struct aw200xx *chip = (struct aw200xx *)data;
> +
> +	aw200xx_disable(chip);

Same

> +}
> +
>   static int aw200xx_probe(struct i2c_client *client)
>   {
>   	const struct aw200xx_chipdef *cdef;
> @@ -568,11 +583,16 @@ static int aw200xx_probe(struct i2c_client *client)
>   
>   	aw200xx_enable(chip);
>   
> +	ret = devm_add_action(&client->dev, aw200xx_disable_action, chip);
> +	if (ret)
> +		return ret;
> +
>   	ret = aw200xx_chip_check(chip);
>   	if (ret)
>   		return ret;
>   
> -	mutex_init(&chip->mutex);
> +	if (devm_mutex_init(&client->dev, &chip->mutex))
> +		return -ENOMEM;

Why not return value returned by dev_mutex_init() directly ?

>   
>   	/* Need a lock now since after call aw200xx_probe_fw, sysfs nodes created */
>   	mutex_lock(&chip->mutex);
> @@ -581,6 +601,10 @@ static int aw200xx_probe(struct i2c_client *client)
>   	if (ret)
>   		goto out_unlock;
>   
> +	ret = devm_add_action(&client->dev, aw200xx_chip_reset_action, chip);
> +	if (ret)
> +		goto out_unlock;
> +
>   	ret = aw200xx_probe_fw(&client->dev, chip);
>   	if (ret)
>   		goto out_unlock;
> @@ -595,15 +619,6 @@ static int aw200xx_probe(struct i2c_client *client)
>   	return ret;
>   }
>   
> -static void aw200xx_remove(struct i2c_client *client)
> -{
> -	struct aw200xx *chip = i2c_get_clientdata(client);
> -
> -	aw200xx_chip_reset(chip);
> -	aw200xx_disable(chip);
> -	mutex_destroy(&chip->mutex);
> -}
> -
>   static const struct aw200xx_chipdef aw20036_cdef = {
>   	.channels = 36,
>   	.display_size_rows_max = 3,
> @@ -652,7 +667,6 @@ static struct i2c_driver aw200xx_driver = {
>   		.of_match_table = aw200xx_match_table,
>   	},
>   	.probe_new = aw200xx_probe,
> -	.remove = aw200xx_remove,
>   	.id_table = aw200xx_id,
>   };
>   module_i2c_driver(aw200xx_driver);