linux-kernel - Re: [PATCH 1/4] input: misc: gp2a: Use managed resource helpers

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Date:   Fri, 25 Jan 2019 17:17:02 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Paweł Chmiel <pawel.mikolaj.chmiel@...il.com>
Cc:     robh+dt@...nel.org, mark.rutland@....com,
        mchehab+samsung@...nel.org, colyli@...e.de,
        ckeepax@...nsource.wolfsonmicro.com, andrew.smirnov@...il.com,
        arnd@...db.de, xiaotong.lu@...eadtrum.com, xc-racer2@...e.ca,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH 1/4] input: misc: gp2a: Use managed resource helpers

On Fri, Jan 25, 2019 at 06:50:42PM +0100, Paweł Chmiel wrote:
> From: Jonathan Bakker <xc-racer2@...e.ca>
> 
> Simplify cleanup of failures by using managed resource helpers
> 
> Signed-off-by: Jonathan Bakker <xc-racer2@...e.ca>
> Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@...il.com>
> ---
>  drivers/input/misc/gp2ap002a00f.c | 37 ++++++++++---------------------
>  1 file changed, 12 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/input/misc/gp2ap002a00f.c b/drivers/input/misc/gp2ap002a00f.c
> index c6a29e57b5e4..79c8c4c56d1a 100644
> --- a/drivers/input/misc/gp2ap002a00f.c
> +++ b/drivers/input/misc/gp2ap002a00f.c
> @@ -138,14 +138,15 @@ static int gp2a_probe(struct i2c_client *client,
>  			return error;
>  	}
>  
> -	error = gpio_request_one(pdata->vout_gpio, GPIOF_IN, GP2A_I2C_NAME);
> +	error = devm_gpio_request_one(&client->dev, pdata->vout_gpio,
> +				      GPIOF_IN, GP2A_I2C_NAME);
>  	if (error)
>  		goto err_hw_shutdown;
>  
> -	dt = kzalloc(sizeof(struct gp2a_data), GFP_KERNEL);
> +	dt = devm_kzalloc(&client->dev, sizeof(struct gp2a_data), GFP_KERNEL);
>  	if (!dt) {
>  		error = -ENOMEM;
> -		goto err_free_gpio;
> +		goto err_hw_shutdown;
>  	}
>  
>  	dt->pdata = pdata;
> @@ -153,12 +154,12 @@ static int gp2a_probe(struct i2c_client *client,
>  
>  	error = gp2a_initialize(dt);
>  	if (error < 0)
> -		goto err_free_mem;
> +		goto err_hw_shutdown;
>  
> -	dt->input = input_allocate_device();
> +	dt->input = devm_input_allocate_device(&client->dev);
>  	if (!dt->input) {
>  		error = -ENOMEM;
> -		goto err_free_mem;
> +		goto err_hw_shutdown;
>  	}
>  
>  	input_set_drvdata(dt->input, dt);
> @@ -171,19 +172,18 @@ static int gp2a_probe(struct i2c_client *client,
>  
>  	input_set_capability(dt->input, EV_SW, SW_FRONT_PROXIMITY);
>  
> -	error = request_threaded_irq(client->irq, NULL, gp2a_irq,
> -			IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
> -				IRQF_ONESHOT,
> -			GP2A_I2C_NAME, dt);
> +	error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
> +			gp2a_irq, IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
> +			IRQF_ONESHOT, GP2A_I2C_NAME, dt);
>  	if (error) {
>  		dev_err(&client->dev, "irq request failed\n");
> -		goto err_free_input_dev;
> +		goto err_hw_shutdown;
>  	}
>  
>  	error = input_register_device(dt->input);
>  	if (error) {
>  		dev_err(&client->dev, "device registration failed\n");
> -		goto err_free_irq;
> +		goto err_hw_shutdown;
>  	}
>  
>  	device_init_wakeup(&client->dev, pdata->wakeup);
> @@ -191,14 +191,6 @@ static int gp2a_probe(struct i2c_client *client,
>  
>  	return 0;
>  
> -err_free_irq:
> -	free_irq(client->irq, dt);
> -err_free_input_dev:
> -	input_free_device(dt->input);
> -err_free_mem:
> -	kfree(dt);
> -err_free_gpio:
> -	gpio_free(pdata->vout_gpio);
>  err_hw_shutdown:
>  	if (pdata->hw_shutdown)
>  		pdata->hw_shutdown(client);
> @@ -210,12 +202,7 @@ static int gp2a_remove(struct i2c_client *client)
>  	struct gp2a_data *dt = i2c_get_clientdata(client);
>  	const struct gp2a_platform_data *pdata = dt->pdata;
>  
> -	free_irq(client->irq, dt);
> -
>  	input_unregister_device(dt->input);

You do not need explicitly unregister input device if it is managed
(allocated with devm).

> -	kfree(dt);
> -
> -	gpio_free(pdata->vout_gpio);
>  
>  	if (pdata->hw_shutdown)
>  		pdata->hw_shutdown(client);

This is however is wrong, as you can't shutdown hardware before
disapling/freeing IRQ, etc. Given that there are no users of
gp2a_platform_data in kernel I'd recommend creating a preparatory patch
removing platform data support from the driver.

Thanks.

-- 
Dmitry