Re: [PATCH 0/4] iio: adc: ad4691: add driver for AD4691 multichannel SAR ADC family

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Thu, Mar 05, 2026 at 02:23:26PM +0200, Radu Sabau via B4 Relay wrote:
> This series adds support for the Analog Devices AD4691 family of
> high-speed, low-power multichannel successive approximation register
> (SAR) ADCs with an SPI-compatible serial interface.
> 
> The family includes:
>   - AD4691: 16-channel, 500 kSPS
>   - AD4692: 16-channel, 1 MSPS
>   - AD4693: 8-channel, 500 kSPS
>   - AD4694: 8-channel, 1 MSPS
> 
> The devices support five operating modes:
>   - CNV Clock Mode:    external PWM drives CNV, samples at PWM rate
>   - CNV Burst Mode:    PWM triggers bursts, internal oscillator drives
>                        conversions within each burst
>   - Autonomous Mode:   internal oscillator drives conversions,
>                        software starts/stops via register write
>   - SPI Burst Mode:    similar to Autonomous Mode but optimised for
>                        SPI burst reads
>   - Manual Mode:       CNV tied to SPI CS; each SPI transfer triggers
>                        a conversion and returns the previous result
>                        (pipelined);

This cover letter doesn't answer to the first important question: Why a brand
new driver? Do your homework and check what is already in the kernel and
explain in the next version why no other existing driver can be reused (refactored).

-- 
With Best Regards,
Andy Shevchenko