Re: [PATCH 1/2] staging:iio:ad7780: Make powerdown GPIO optional

[Jonathan Cameron <jic23@kernel.org>]

On 09/21/2012 02:29 PM, Lars-Peter Clausen wrote:
> Some designs hardwire the PDRST pin to always on. In this case there is no GPIO
> to control the mode of the device, so make the GPIO optional. Since now all of
> the the platform data fields are optional now, make the platform data as a whole
> optional as well.
> 
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
added to togreg branch of iio.git
> ---
>  drivers/staging/iio/adc/ad7780.c |   31 +++++++++++++++++--------------
>  1 file changed, 17 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/staging/iio/adc/ad7780.c b/drivers/staging/iio/adc/ad7780.c
> index 5f807ce..1dd7cdb 100644
> --- a/drivers/staging/iio/adc/ad7780.c
> +++ b/drivers/staging/iio/adc/ad7780.c
> @@ -73,7 +73,8 @@ static int ad7780_set_mode(struct ad_sigma_delta *sigma_delta,
>  		break;
>  	}
>  
> -	gpio_set_value(st->powerdown_gpio, val);
> +	if (gpio_is_valid(st->powerdown_gpio))
> +		gpio_set_value(st->powerdown_gpio, val);
>  
>  	return 0;
>  }
> @@ -148,11 +149,6 @@ static int __devinit ad7780_probe(struct spi_device *spi)
>  	struct iio_dev *indio_dev;
>  	int ret, voltage_uv = 0;
>  
> -	if (!pdata) {
> -		dev_dbg(&spi->dev, "no platform data?\n");
> -		return -ENODEV;
> -	}
> -
>  	indio_dev = iio_device_alloc(sizeof(*st));
>  	if (indio_dev == NULL)
>  		return -ENOMEM;
> @@ -174,8 +170,6 @@ static int __devinit ad7780_probe(struct spi_device *spi)
>  	st->chip_info =
>  		&ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
>  
> -	st->powerdown_gpio = pdata->gpio_pdrst;
> -
>  	if (pdata && pdata->vref_mv)
>  		st->int_vref_mv = pdata->vref_mv;
>  	else if (voltage_uv)
> @@ -192,11 +186,17 @@ static int __devinit ad7780_probe(struct spi_device *spi)
>  	indio_dev->num_channels = 1;
>  	indio_dev->info = &ad7780_info;
>  
> -	ret = gpio_request_one(pdata->gpio_pdrst, GPIOF_OUT_INIT_LOW,
> +	if (pdata && gpio_is_valid(pdata->gpio_pdrst)) {
> +
> +		ret = gpio_request_one(pdata->gpio_pdrst, GPIOF_OUT_INIT_LOW,
>  			       "AD7780 /PDRST");
> -	if (ret) {
> -		dev_err(&spi->dev, "failed to request GPIO PDRST\n");
> -		goto error_disable_reg;
> +		if (ret) {
> +			dev_err(&spi->dev, "failed to request GPIO PDRST\n");
> +			goto error_disable_reg;
> +		}
> +		st->powerdown_gpio = pdata->gpio_pdrst;
> +	} else {
> +		st->powerdown_gpio = -1;
>  	}
>  
>  	ret = ad_sd_setup_buffer_and_trigger(indio_dev);
> @@ -212,7 +212,8 @@ static int __devinit ad7780_probe(struct spi_device *spi)
>  error_cleanup_buffer_and_trigger:
>  	ad_sd_cleanup_buffer_and_trigger(indio_dev);
>  error_free_gpio:
> -	gpio_free(pdata->gpio_pdrst);
> +	if (pdata && gpio_is_valid(pdata->gpio_pdrst))
> +		gpio_free(pdata->gpio_pdrst);
>  error_disable_reg:
>  	if (!IS_ERR(st->reg))
>  		regulator_disable(st->reg);
> @@ -233,7 +234,9 @@ static int __devexit ad7780_remove(struct spi_device *spi)
>  	iio_device_unregister(indio_dev);
>  	ad_sd_cleanup_buffer_and_trigger(indio_dev);
>  
> -	gpio_free(st->powerdown_gpio);
> +	if (gpio_is_valid(st->powerdown_gpio))
> +		gpio_free(st->powerdown_gpio);
> +
>  	if (!IS_ERR(st->reg)) {
>  		regulator_disable(st->reg);
>  		regulator_put(st->reg);
>