Re: [PATCH v9 10/17] iio: frequency: ad9910: initial driver implementation

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 22 Jul 2026 16:50:19 +0100
Rodrigo Alencar via B4 Relay <devnull+rodrigo.alencar.analog.com@kernel.org> wrote:

> From: Rodrigo Alencar <rodrigo.alencar@analog.com>
> 
> Add the core AD9910 DDS driver infrastructure with single tone mode
> support. This includes SPI register access, profile management via GPIO
> pins, PLL/DAC configuration from firmware properties, and single tone
> frequency/phase/amplitude control through IIO attributes.
> 
> Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>

...

> diff --git a/drivers/iio/frequency/ad9910.c b/drivers/iio/frequency/ad9910.c
> new file mode 100644
> index 000000000000..b41b011af281
> --- /dev/null
> +++ b/drivers/iio/frequency/ad9910.c

...

> +static int ad9910_parse_fw(struct ad9910_state *st)
> +{
> +	static const char * const refclk_out_drv0[] = {
> +		"disabled", "low", "medium", "high",
> +	};
> +	struct device *dev = &st->spi->dev;
> +	const char *prop;
> +	u32 tmp;
> +	int ret;
> +
> +	st->data.pll_enabled = device_property_read_bool(dev, "adi,pll-enable");
> +	if (st->data.pll_enabled) {
> +		prop = "adi,charge-pump-current-microamp";
> +		if (device_property_present(dev, prop)) {
> +			ret = device_property_read_u32(dev, prop, &tmp);
> +			if (ret)
> +				return dev_err_probe(dev, ret, "property read: %s\n", prop);
> +
> +			if (tmp < AD9910_ICP_MIN_uA || tmp > AD9910_ICP_MAX_uA)
> +				return dev_err_probe(dev, -ERANGE,
> +						     "invalid charge pump current %u\n", tmp);
> +		} else {
> +			tmp = AD9910_ICP_MIN_uA;
> +		}
> +		st->data.pll_charge_pump_current = tmp;
> +
> +		prop = "adi,refclk-out-drive-strength";

Sashiko did have a question about this.  I didn't care enough about the particular
combination restrictions on the clock being output, but please have a quick check.
https://sashiko.dev/#/patchset/20260722-ad9910-iio-driver-v9-0-459d1df5ac56%40analog.com

If it is possible but nonsensical, add a comment here.

> +		if (device_property_present(dev, prop)) {
> +			ret = device_property_match_property_string(dev, prop,
> +								    refclk_out_drv0,
> +								    ARRAY_SIZE(refclk_out_drv0));
> +			if (ret < 0)
> +				return dev_err_probe(dev, ret, "property read: %s\n", prop);
> +
> +			st->data.refclk_out_drv = ret;
> +		}
> +	}
> +
> +	return 0;
> +}