linux-kernel - Re: pca953x: support working w/o platform data

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Message-ID: <4E0E0138.8060400@compulab.co.il>
Date:	Fri, 01 Jul 2011 20:17:44 +0300
From:	Igor Grinberg <grinberg@...pulab.co.il>
To:	Christian Gmeiner <christian.gmeiner@...il.com>
CC:	linux-kernel@...r.kernel.org, grant.likely@...retlab.ca
Subject: Re: pca953x: support working w/o platform data

On 07/01/11 14:33, Christian Gmeiner wrote:

> Provide defaults for pca953x, so the driver can be used w/o
> providing platform data.

Wouldn't it be better to provide a default pdata structure inside the driver
and use it in case no pdata supplied, so you will not have to patch the
driver all around checking each time if pdata is valid?

> Signed-off-by: Christian Gmeiner <christian.gmeiner@...il.com>
> ---
>  pca953x.c |   21 +++++++++++----------
>  1 file changed, 11 insertions(+), 10 deletions(-)
> diff -Nur linux-3.0-rc5/drivers/gpio//pca953x.c
> linux-3.0-rc5__patched/drivers/gpio//pca953x.c
> --- linux-3.0-rc5/drivers/gpio//pca953x.c	2011-06-28 04:12:22.000000000 +0200
> +++ linux-3.0-rc5__patched/drivers/gpio//pca953x.c	2011-07-01
> 13:19:08.369130336 +0200
> @@ -452,7 +452,7 @@
>  	struct pca953x_platform_data *pdata = client->dev.platform_data;
>  	int ret, offset = 0;
>
> -	if (pdata->irq_base != -1
> +	if (pdata && pdata->irq_base != -1
>  			&& (id->driver_data & PCA_INT)) {
>  		int lvl;
>
> @@ -524,7 +524,7 @@
>  	struct i2c_client *client = chip->client;
>  	struct pca953x_platform_data *pdata = client->dev.platform_data;
>
> -	if (pdata->irq_base != -1 && (id->driver_data & PCA_INT))
> +	if (pdata && pdata->irq_base != -1 && (id->driver_data & PCA_INT))
>  		dev_warn(&client->dev, "interrupt support not compiled in\n");
>
>  	return 0;
> @@ -643,6 +643,7 @@
>  	struct pca953x_platform_data *pdata;
>  	struct pca953x_chip *chip;
>  	int ret = 0;
> +	int invert = 0;
>
>  	chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
>  	if (chip == NULL)
> @@ -660,15 +661,13 @@
>
>  	if (pdata == NULL) {
>  		dev_dbg(&client->dev, "no platform data\n");
> -		ret = -EINVAL;
> -		goto out_failed;
>  	}
>
>  	chip->client = client;
>
> -	chip->gpio_start = pdata->gpio_base;
> +	chip->gpio_start = pdata ? pdata->gpio_base : -1;
>
> -	chip->names = pdata->names;
> +	chip->names = pdata ? pdata->names : NULL;
>  	chip->chip_type = id->driver_data & (PCA953X_TYPE | PCA957X_TYPE);
>
>  	mutex_init(&chip->i2c_lock);
> @@ -678,10 +677,12 @@
>  	 */
>  	pca953x_setup_gpio(chip, id->driver_data & PCA_GPIO_MASK);
>
> +	invert = pdata ? pdata->invert : 0;
> +
>  	if (chip->chip_type == PCA953X_TYPE)
> -		device_pca953x_init(chip, pdata->invert);
> +		device_pca953x_init(chip, invert);
>  	else if (chip->chip_type == PCA957X_TYPE)
> -		device_pca957x_init(chip, pdata->invert);
> +		device_pca957x_init(chip, invert);
>  	else
>  		goto out_failed;
>
> @@ -693,7 +694,7 @@
>  	if (ret)
>  		goto out_failed_irq;
>
> -	if (pdata->setup) {
> +	if (pdata && pdata->setup) {
>  		ret = pdata->setup(client, chip->gpio_chip.base,
>  				chip->gpio_chip.ngpio, pdata->context);
>  		if (ret < 0)
> @@ -717,7 +718,7 @@
>  	struct pca953x_chip *chip = i2c_get_clientdata(client);
>  	int ret = 0;
>
> -	if (pdata->teardown) {
> +	if (pdata && pdata->teardown) {
>  		ret = pdata->teardown(client, chip->gpio_chip.base,
>  				chip->gpio_chip.ngpio, pdata->context);
>  		if (ret < 0) {
> ---
> --
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-- 
Regards,
Igor.

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