Re: [PATCH]staging:iio:ad799x make use of platform_data optional

[Jonathan Cameron <jic23@kernel.org>]

On 29/12/13 11:49, Hartmut Knaack wrote:
> Setting Vref with platform_data is a neat feature, though it is not essential
> for operating these devices. So make the use of platform_data optional and set
> default value of 1000 mV if nothing else is defined.
>
> Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>

Hi Hartmut,

Why a default of 1V?  Does that correspond to anything in particular?

Whilst the way this is set here is clunky there is a need for this 
voltage to be supplied in some fashion.  Now we'd do it via a regulator
to give us nice standard device tree bindings and to allow for less 
simplistic hardware configurations.

So lets say we convert this to use a regulator, is there still a reason 
why one might want a default value?

Jonathan


> ---
> diff --git a/drivers/staging/iio/adc/ad799x_core.c b/drivers/staging/iio/adc/ad799x_core.c
> index 9428be8..e32a555 100644
> --- a/drivers/staging/iio/adc/ad799x_core.c
> +++ b/drivers/staging/iio/adc/ad799x_core.c
> @@ -545,10 +545,12 @@ static int ad799x_probe(struct i2c_client *client,
>
>   	/* TODO: Add pdata options for filtering and bit delay */
>
> -	if (!pdata)
> -		return -EINVAL;
> -
> -	st->int_vref_mv = pdata->vref_mv;
> +	if ((!pdata) || (!pdata->vref_mv)) {
> +		dev_warn(&client->dev,
> +			 "No platform data found, setting Vref to 1000 mV\n");
> +		st->int_vref_mv = 1000;
> +	} else
> +		st->int_vref_mv = pdata->vref_mv;
>
>   	st->reg = devm_regulator_get(&client->dev, "vcc");
>   	if (!IS_ERR(st->reg)) {
> --
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