Re: [PATCH v4 11/11] iio: dac: adi-axi-dac: add registering of child fdt node

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 03 Oct 2024 19:29:08 +0200
Angelo Dureghello <adureghello@baylibre.com> wrote:

> From: Angelo Dureghello <adureghello@baylibre.com>
> 
> Change to obtain the fdt use case as reported in the
> adi,ad3552r.yaml file in this patchset.
> 
> The DAC device is defined as a child node of the backend.
> Registering the child fdt node as a platform devices.
> 
> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>

One issue inline,

J
> @@ -750,6 +753,45 @@ static int axi_dac_bus_reg_read(struct iio_backend *back, u32 reg, u32 *val,
>  	return regmap_read(st->regmap, AXI_DAC_CUSTOM_RD_REG, val);
>  }
>  
> +static void axi_dac_child_remove(void *data)
> +{
> +	struct axi_dac_state *st = data;
> +
> +	if (st->dac_pdev)

This condition doesn't make sense - see below.

> +		platform_device_unregister(st->dac_pdev);
> +}
> +
> +static int axi_dac_create_platform_device(struct axi_dac_state *st,
> +					  struct fwnode_handle *child)
> +{
> +	struct ad3552r_hs_platform_data pdata = {
> +		.bus_reg_read = axi_dac_bus_reg_read,
> +		.bus_reg_write = axi_dac_bus_reg_write,
> +	};
> +	struct platform_device_info pi = {
> +		.parent = st->dev,
> +		.name = fwnode_get_name(child),
> +		.id = PLATFORM_DEVID_AUTO,
> +		.fwnode = child,
> +		.data = &pdata,
> +		.size_data = sizeof(pdata),
> +	};
> +	struct platform_device *pdev;
> +	int ret;
> +
> +	pdev = platform_device_register_full(&pi);
> +	if (IS_ERR(pdev))
> +		return PTR_ERR(pdev);
> +
> +	ret = devm_add_action_or_reset(st->dev, axi_dac_child_remove, st);
> +	if (ret)

If you hit this path, then st->dac_pdev is not set and we don't remove
it.  Set st->dac_pdev = dev before the devm_add_action_or_reset()
call and then drop the check in there as it will always be set.


> +		return ret;
> +
> +	st->dac_pdev = pdev;
> +
> +	return 0;
> +}