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Date:   Thu, 6 Feb 2020 10:01:19 +0000
From:   Jonathan Cameron <jic23@kernel.org>
To:     Alexandru Tachici <alexandru.tachici@analog.com>
Cc:     <linux-iio@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/5 V2] staging: iio: adc: ad7192: modify iio_chan_spec
 array
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        <20200205171511.25912-3-alexandru.tachici@analog.com>
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On Wed, 5 Feb 2020 19:15:08 +0200
Alexandru Tachici <alexandru.tachici@analog.com> wrote:

> This patch changes the static const struct iio_chan_spec arrays
> in a way that all the necessary attributes are set at
> compile time. Now ad7192_channels_config only makes the
> channels attribute of iio_dev point to the right array depending
> on the chip.
> 
> Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Great.  Not directly related to this patch, but a question about
docs inline.

Thanks,

Jonathan

> ---
>  drivers/staging/iio/adc/ad7192.c | 112 ++++++++++++++++++-------------
>  1 file changed, 66 insertions(+), 46 deletions(-)
> 
> diff --git a/drivers/staging/iio/adc/ad7192.c b/drivers/staging/iio/adc/ad7192.c
> index 4780ddf99b13..8f2fa154876a 100644
> --- a/drivers/staging/iio/adc/ad7192.c
> +++ b/drivers/staging/iio/adc/ad7192.c
> @@ -786,73 +786,93 @@ static const struct iio_info ad7195_info = {
>  	.validate_trigger = ad_sd_validate_trigger,
>  };
>  
> +#define __AD719x_CHANNEL(_si, _channel1, _channel2, _address, _extend_name, \
> +	_type, _mask_type_av, _ext_info) \
> +	{ \
> +		.type = (_type), \
> +		.differential = ((_channel2) == -1 ? 0 : 1), \
> +		.indexed = 1, \
> +		.channel = (_channel1), \
> +		.channel2 = (_channel2), \
> +		.address = (_address), \
> +		.extend_name = (_extend_name), \
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> +			BIT(IIO_CHAN_INFO_OFFSET), \
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> +		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
> +			BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), \
> +		.info_mask_shared_by_type_available = (_mask_type_av), \
> +		.ext_info = (_ext_info), \
> +		.scan_index = (_si), \
> +		.scan_type = { \
> +			.sign = 'u', \
> +			.realbits = 24, \
> +			.storagebits = 32, \
> +			.endianness = IIO_BE, \
> +		}, \
> +	}
> +
> +#define AD719x_DIFF_CHANNEL(_si, _channel1, _channel2, _address) \
> +	__AD719x_CHANNEL(_si, _channel1, _channel2, _address, NULL, \
> +		IIO_VOLTAGE, BIT(IIO_CHAN_INFO_SCALE), \
> +		ad7192_calibsys_ext_info)
> +
> +#define AD719x_CHANNEL(_si, _channel1, _address) \
> +	__AD719x_CHANNEL(_si, _channel1, -1, _address, NULL, IIO_VOLTAGE, \
> +		BIT(IIO_CHAN_INFO_SCALE), ad7192_calibsys_ext_info)
> +
> +#define AD719x_SHORTED_CHANNEL(_si, _channel1, _address) \
> +	__AD719x_CHANNEL(_si, _channel1, -1, _address, "shorted", IIO_VOLTAGE, \
> +		BIT(IIO_CHAN_INFO_SCALE), ad7192_calibsys_ext_info)

Just to check, is this one documented?  It will result in new ABI afterall.

> +
> +#define AD719x_TEMP_CHANNEL(_si, _address) \
> +	__AD719x_CHANNEL(_si, 0, -1, _address, NULL, IIO_TEMP, 0, NULL)
> +
>  static const struct iio_chan_spec ad7192_channels[] = {
> -	AD_SD_DIFF_CHANNEL(0, 1, 2, AD7192_CH_AIN1P_AIN2M, 24, 32, 0),
> -	AD_SD_DIFF_CHANNEL(1, 3, 4, AD7192_CH_AIN3P_AIN4M, 24, 32, 0),
> -	AD_SD_TEMP_CHANNEL(2, AD7192_CH_TEMP, 24, 32, 0),
> -	AD_SD_SHORTED_CHANNEL(3, 2, AD7192_CH_AIN2P_AIN2M, 24, 32, 0),
> -	AD_SD_CHANNEL(4, 1, AD7192_CH_AIN1, 24, 32, 0),
> -	AD_SD_CHANNEL(5, 2, AD7192_CH_AIN2, 24, 32, 0),
> -	AD_SD_CHANNEL(6, 3, AD7192_CH_AIN3, 24, 32, 0),
> -	AD_SD_CHANNEL(7, 4, AD7192_CH_AIN4, 24, 32, 0),
> +	AD719x_DIFF_CHANNEL(0, 1, 2, AD7192_CH_AIN1P_AIN2M),
> +	AD719x_DIFF_CHANNEL(1, 3, 4, AD7192_CH_AIN3P_AIN4M),
> +	AD719x_TEMP_CHANNEL(2, AD7192_CH_TEMP),
> +	AD719x_SHORTED_CHANNEL(3, 2, AD7192_CH_AIN2P_AIN2M),
> +	AD719x_CHANNEL(4, 1, AD7192_CH_AIN1),
> +	AD719x_CHANNEL(5, 2, AD7192_CH_AIN2),
> +	AD719x_CHANNEL(6, 3, AD7192_CH_AIN3),
> +	AD719x_CHANNEL(7, 4, AD7192_CH_AIN4),
>  	IIO_CHAN_SOFT_TIMESTAMP(8),
>  };
>  
>  static const struct iio_chan_spec ad7193_channels[] = {
> -	AD_SD_DIFF_CHANNEL(0, 1, 2, AD7193_CH_AIN1P_AIN2M, 24, 32, 0),
> -	AD_SD_DIFF_CHANNEL(1, 3, 4, AD7193_CH_AIN3P_AIN4M, 24, 32, 0),
> -	AD_SD_DIFF_CHANNEL(2, 5, 6, AD7193_CH_AIN5P_AIN6M, 24, 32, 0),
> -	AD_SD_DIFF_CHANNEL(3, 7, 8, AD7193_CH_AIN7P_AIN8M, 24, 32, 0),
> -	AD_SD_TEMP_CHANNEL(4, AD7193_CH_TEMP, 24, 32, 0),
> -	AD_SD_SHORTED_CHANNEL(5, 2, AD7193_CH_AIN2P_AIN2M, 24, 32, 0),
> -	AD_SD_CHANNEL(6, 1, AD7193_CH_AIN1, 24, 32, 0),
> -	AD_SD_CHANNEL(7, 2, AD7193_CH_AIN2, 24, 32, 0),
> -	AD_SD_CHANNEL(8, 3, AD7193_CH_AIN3, 24, 32, 0),
> -	AD_SD_CHANNEL(9, 4, AD7193_CH_AIN4, 24, 32, 0),
> -	AD_SD_CHANNEL(10, 5, AD7193_CH_AIN5, 24, 32, 0),
> -	AD_SD_CHANNEL(11, 6, AD7193_CH_AIN6, 24, 32, 0),
> -	AD_SD_CHANNEL(12, 7, AD7193_CH_AIN7, 24, 32, 0),
> -	AD_SD_CHANNEL(13, 8, AD7193_CH_AIN8, 24, 32, 0),
> +	AD719x_DIFF_CHANNEL(0, 1, 2, AD7193_CH_AIN1P_AIN2M),
> +	AD719x_DIFF_CHANNEL(1, 3, 4, AD7193_CH_AIN3P_AIN4M),
> +	AD719x_DIFF_CHANNEL(2, 5, 6, AD7193_CH_AIN5P_AIN6M),
> +	AD719x_DIFF_CHANNEL(3, 7, 8, AD7193_CH_AIN7P_AIN8M),
> +	AD719x_TEMP_CHANNEL(4, AD7193_CH_TEMP),
> +	AD719x_SHORTED_CHANNEL(5, 2, AD7193_CH_AIN2P_AIN2M),
> +	AD719x_CHANNEL(6, 1, AD7193_CH_AIN1),
> +	AD719x_CHANNEL(7, 2, AD7193_CH_AIN2),
> +	AD719x_CHANNEL(8, 3, AD7193_CH_AIN3),
> +	AD719x_CHANNEL(9, 4, AD7193_CH_AIN4),
> +	AD719x_CHANNEL(10, 5, AD7193_CH_AIN5),
> +	AD719x_CHANNEL(11, 6, AD7193_CH_AIN6),
> +	AD719x_CHANNEL(12, 7, AD7193_CH_AIN7),
> +	AD719x_CHANNEL(13, 8, AD7193_CH_AIN8),
>  	IIO_CHAN_SOFT_TIMESTAMP(14),
>  };
>  
>  static int ad7192_channels_config(struct iio_dev *indio_dev)
>  {
>  	struct ad7192_state *st = iio_priv(indio_dev);
> -	const struct iio_chan_spec *channels;
> -	struct iio_chan_spec *chan;
> -	int i;
>  
>  	switch (st->devid) {
>  	case ID_AD7193:
> -		channels = ad7193_channels;
> +		indio_dev->channels = ad7193_channels;
>  		indio_dev->num_channels = ARRAY_SIZE(ad7193_channels);
>  		break;
>  	default:
> -		channels = ad7192_channels;
> +		indio_dev->channels = ad7192_channels;
>  		indio_dev->num_channels = ARRAY_SIZE(ad7192_channels);
>  		break;
>  	}
>  
> -	chan = devm_kcalloc(indio_dev->dev.parent, indio_dev->num_channels,
> -			    sizeof(*chan), GFP_KERNEL);
> -	if (!chan)
> -		return -ENOMEM;
> -
> -	indio_dev->channels = chan;
> -
> -	for (i = 0; i < indio_dev->num_channels; i++) {
> -		*chan = channels[i];
> -		chan->info_mask_shared_by_all |=
> -			BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY);
> -		if (chan->type != IIO_TEMP) {
> -			chan->info_mask_shared_by_type_available |=
> -				BIT(IIO_CHAN_INFO_SCALE);
> -			chan->ext_info = ad7192_calibsys_ext_info;
> -		}
> -		chan++;
> -	}
> -
>  	return 0;
>  }
>