Re: [PATCH 1/2] iio: adc: ad9467: include two's complement in default mode

["Nuno Sá" <noname.nuno@gmail.com>]

On Tue, 2025-12-16 at 11:40 +0000, Tomas Melin wrote:
> All supported drivers currently implicitly use two's complement mode.
> Make this clear by declaring two's complement in the default
> output mode. Calibration mode uses offset binary, so change the output
> mode only when running the calibration or other test mode.
> 
> Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
> ---

Reviewed-by: Nuno Sá <nuno.sa@analog.com>

>  drivers/iio/adc/ad9467.c | 33 +++++++++++++++++++++++++--------
>  1 file changed, 25 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/iio/adc/ad9467.c b/drivers/iio/adc/ad9467.c
> index 59c3fa3bcc9b0b8b36b78c3b54fd7977cae23496..60fc3361b2689a4c38287c613ef93fe00338e5fa 100644
> --- a/drivers/iio/adc/ad9467.c
> +++ b/drivers/iio/adc/ad9467.c
> @@ -72,6 +72,7 @@
>  #define AN877_ADC_OUTPUT_MODE_OFFSET_BINARY	0x0
>  #define AN877_ADC_OUTPUT_MODE_TWOS_COMPLEMENT	0x1
>  #define AN877_ADC_OUTPUT_MODE_GRAY_CODE		0x2
> +#define AN877_ADC_OUTPUT_MODE_MASK		GENMASK(1, 0)
>  
>  /* AN877_ADC_REG_OUTPUT_PHASE */
>  #define AN877_ADC_OUTPUT_EVEN_ODD_MODE_EN	0x20
> @@ -85,7 +86,7 @@
>   */
>  
>  #define CHIPID_AD9211			0x06
> -#define AD9211_DEF_OUTPUT_MODE		0x00
> +#define AD9211_DEF_OUTPUT_MODE		0x01
>  #define AD9211_REG_VREF_MASK		GENMASK(4, 0)
>  
>  /*
> @@ -93,7 +94,7 @@
>   */
>  
>  #define CHIPID_AD9265			0x64
> -#define AD9265_DEF_OUTPUT_MODE		0x40
> +#define AD9265_DEF_OUTPUT_MODE		0x41
>  #define AD9265_REG_VREF_MASK		0xC0
>  
>  /*
> @@ -101,7 +102,7 @@
>   */
>  
>  #define CHIPID_AD9434			0x6A
> -#define AD9434_DEF_OUTPUT_MODE		0x00
> +#define AD9434_DEF_OUTPUT_MODE		0x01
>  #define AD9434_REG_VREF_MASK		0xC0
>  
>  /*
> @@ -109,7 +110,7 @@
>   */
>  
>  #define CHIPID_AD9467			0x50
> -#define AD9467_DEF_OUTPUT_MODE		0x08
> +#define AD9467_DEF_OUTPUT_MODE		0x09
>  #define AD9467_REG_VREF_MASK		0x0F
>  
>  /*
> @@ -117,6 +118,7 @@
>   */
>  
>  #define CHIPID_AD9643			0x82
> +#define AD9643_DEF_OUTPUT_MODE		0x01
>  #define AD9643_REG_VREF_MASK		0x1F
>  
>  /*
> @@ -124,6 +126,7 @@
>   */
>  
>  #define CHIPID_AD9652                   0xC1
> +#define AD9652_DEF_OUTPUT_MODE		0x01
>  #define AD9652_REG_VREF_MASK            0xC0
>  
>  /*
> @@ -131,6 +134,7 @@
>   */
>  
>  #define CHIPID_AD9649			0x6F
> +#define AD9649_DEF_OUTPUT_MODE		0x01
>  #define AD9649_TEST_POINTS		8
>  
>  #define AD9647_MAX_TEST_POINTS		32
> @@ -461,6 +465,7 @@ static const struct ad9467_chip_info ad9643_chip_tbl = {
>  	.test_mask = BIT(AN877_ADC_TESTMODE_RAMP) |
>  		GENMASK(AN877_ADC_TESTMODE_MIXED_BIT_FREQUENCY, AN877_ADC_TESTMODE_OFF),
>  	.test_mask_len = AN877_ADC_TESTMODE_RAMP + 1,
> +	.default_output_mode = AD9643_DEF_OUTPUT_MODE,
>  	.vref_mask = AD9643_REG_VREF_MASK,
>  	.has_dco = true,
>  	.has_dco_invert = true,
> @@ -479,6 +484,7 @@ static const struct ad9467_chip_info ad9649_chip_tbl = {
>  	.test_mask = GENMASK(AN877_ADC_TESTMODE_MIXED_BIT_FREQUENCY,
>  			     AN877_ADC_TESTMODE_OFF),
>  	.test_mask_len = AN877_ADC_TESTMODE_MIXED_BIT_FREQUENCY + 1,
> +	.default_output_mode = AD9649_DEF_OUTPUT_MODE,
>  	.has_dco = true,
>  	.has_dco_invert = true,
>  	.dco_en = AN877_ADC_DCO_DELAY_ENABLE,
> @@ -496,6 +502,7 @@ static const struct ad9467_chip_info ad9652_chip_tbl = {
>  	.test_mask = GENMASK(AN877_ADC_TESTMODE_ONE_ZERO_TOGGLE,
>  			     AN877_ADC_TESTMODE_OFF),
>  	.test_mask_len = AN877_ADC_TESTMODE_ONE_ZERO_TOGGLE + 1,
> +	.default_output_mode = AD9652_DEF_OUTPUT_MODE,
>  	.vref_mask = AD9652_REG_VREF_MASK,
>  	.has_dco = true,
>  };
> @@ -671,10 +678,14 @@ static int ad9467_backend_testmode_off(struct ad9467_state *st,
>  
>  static int ad9647_calibrate_prepare(struct ad9467_state *st)
>  {
> +	unsigned int cmode;
>  	unsigned int c;
>  	int ret;
>  
> -	ret = ad9467_outputmode_set(st, st->info->default_output_mode);
> +	cmode = (st->info->default_output_mode & ~AN877_ADC_OUTPUT_MODE_MASK) |
> +		FIELD_PREP(AN877_ADC_OUTPUT_MODE_MASK,
> +			   AN877_ADC_OUTPUT_MODE_OFFSET_BINARY);
> +	ret = ad9467_outputmode_set(st, cmode);
>  	if (ret)
>  		return ret;
>  
> @@ -778,7 +789,7 @@ static int ad9647_calibrate_stop(struct ad9467_state *st)
>  			return ret;
>  	}
>  
> -	mode = st->info->default_output_mode | AN877_ADC_OUTPUT_MODE_TWOS_COMPLEMENT;
> +	mode = st->info->default_output_mode;
>  	return ad9467_outputmode_set(st, mode);
>  }
>  
> @@ -1174,12 +1185,18 @@ static ssize_t ad9467_chan_test_mode_write(struct file *file,
>  		if (ret)
>  			return ret;
>  
> -		out_mode = st->info->default_output_mode | AN877_ADC_OUTPUT_MODE_TWOS_COMPLEMENT;
> +		out_mode = st->info->default_output_mode;
>  		ret = ad9467_outputmode_set(st, out_mode);
>  		if (ret)
>  			return ret;
>  	} else {
> -		ret = ad9467_outputmode_set(st, st->info->default_output_mode);
> +		unsigned int cmode;
> +
> +		cmode = (st->info->default_output_mode &
> +			~AN877_ADC_OUTPUT_MODE_MASK) |
> +			FIELD_PREP(AN877_ADC_OUTPUT_MODE_MASK,
> +				   AN877_ADC_OUTPUT_MODE_OFFSET_BINARY);
> +		ret = ad9467_outputmode_set(st, cmode);
>  		if (ret)
>  			return ret;
>