Re: [PATCH v3 0/4] iio: adc: ad4691: add driver for AD4691 multichannel SAR ADC family

[Andy Shevchenko]

On Fri, Mar 13, 2026 at 12:07:24PM +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 two operating modes, auto-detected from the device
> tree:
>   - CNV Clock Mode: external PWM drives CNV independently of SPI;
>                     DATA_READY on GP0 signals end of conversion
>   - Manual Mode: CNV tied to SPI CS; each SPI transfer reads
>                  the previous conversion result and starts the
>                  next (pipelined N+1 scheme)
> 
> A new driver is warranted rather than extending ad4695: the AD4691
> data path uses an accumulator-register model — results are read from
> AVG_IN registers, with ACC_MASK, ADC_SETUP, DEVICE_SETUP, and
> GPIO_MODE registers controlling the sequencer — none of which exist
> in AD4695. CNV Clock Mode (PWM drives CNV independently of SPI) and
> Manual Mode (pipelined N+1 transfers) also have no equivalent in
> AD4695's command-embedded single-cycle protocol.
> 
> The series is structured as follows:
>   1/4 - DT bindings (YAML schema + dt-bindings header) and
>         MAINTAINERS entry
>   2/4 - Initial driver: register map via custom regmap callbacks,
>         IIO read_raw/write_raw, both operating modes, single-channel
>           reads via internal oscillator (Autonomous Mode)
>   3/4 - Triggered buffer support: IRQ-driven (DATA_READY on GP0) for
>         CNV Clock Mode; hrtimer-based trigger for Manual Mode to
>         handle the pipelined N+1 SPI protocol
>   4/4 - SPI Engine offload support: DMA-backed high-throughput
>         capture path using the SPI offload subsystem

I stopped review where I stopped because I have a feeling that you ignored some
of my comments from the previous version. Why? What's going on?

-- 
With Best Regards,
Andy Shevchenko