Re: [PATCH 6/6] iio: adc: ltc2497: enable line-frequency rejection on LTC2493

[Jonathan Cameron]

On Fri, 09 Oct 2026 11:43:39 +0300
Andrei Stancovici via B4 Relay <devnull+andrei.stancovici.analog.com@xxxxxxxxxx> wrote:

> From: Andrei Stancovici <andrei.stancovici@xxxxxxxxxx>
> 
> The LTC2493 carries the same second configuration byte as the LTC2499,
> with identical FA/FB line-rejection semantics and the same per-rejection
> conversion times (50Hz-only being the longest at 163.5ms). The generic
> filter_mode infrastructure is already implemented in the core and enabled
> for the LTC2499. Enable the same flag for the LTC2493.
> 
> Tested on live LTC2493 hardware connected through an IIO network backend:
> all three modes are selectable; conversion times are respected; voltage
> and temperature reads succeed in each mode with no -EIO.
> 
> Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/2493fe.pdf
> Signed-off-by: Andrei Stancovici <andrei.stancovici@xxxxxxxxxx>
> ---
>  drivers/iio/adc/ltc2497.c | 1 +
>  drivers/iio/adc/ltc2497.h | 2 +-
>  2 files changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/adc/ltc2497.c b/drivers/iio/adc/ltc2497.c
> index 0df2ad9b3243..d668a81f1ff7 100644
> --- a/drivers/iio/adc/ltc2497.c
> +++ b/drivers/iio/adc/ltc2497.c
> @@ -195,6 +195,7 @@ static const struct ltc2497_chip_info ltc2497_info[] = {
>  		.name = "ltc2493",
>  		.has_temp = true,
>  		.has_speed_mode = true,
> +		.has_rejection_mode = true,
I can't see a reason not do combine this with previous patch.

>  		.four_channel = true,
>  	},
>  	[TYPE_LTC2497] = {
> diff --git a/drivers/iio/adc/ltc2497.h b/drivers/iio/adc/ltc2497.h
> index 34ea62c2a4bc..af939e57e1f8 100644
> --- a/drivers/iio/adc/ltc2497.h
> +++ b/drivers/iio/adc/ltc2497.h
> @@ -50,7 +50,7 @@ struct ltc2497_chip_info {
>  	u32 resolution;
>  	bool has_temp;
>  	bool has_speed_mode;	/* SPD bit in the 2nd config byte (LTC2499/LTC2493) */
> -	bool has_rejection_mode;	/* FA/FB bits in the 2nd config byte (LTC2499) */
> +	bool has_rejection_mode;	/* FA/FB bits in the 2nd config byte (LTC2499/LTC2493) */
Particularly as reduces churn here.

>  	bool four_channel;	/* 4 inputs (LTC2493) instead of 16 */
>  };
>  
>