Re: [PATCH 2/3] fpga bus driver

[Pavel Machek <pavel@denx.de>]

Hi!

> Here's a simple example. Start with:
>   * the altera-gpio driver built in to the kernel but not in the
>     device tree.
>   * raw fpga image at /lib/firmware/soc_system.rbf
>   * Load appropriate device tree overlay in configfs by doing
>     $ mkdir /config/device-tree/overlays/1
>     $ echo socfpga_overlay.dtbo > /config/device-tree/overlays/1/path
>   * This results in the FPGA getting programmed and the altera
>     gpio driver getting probed.

Nice!

> +/* Find the fpga manager that is pointed to by a phandle */
> +struct fpga_manager *of_fpga_mgr_dev_lookup(struct device_node *node,
> +					    const char *mgr_property,
> +					    int *ret)
> +{
> +	struct fpga_manager *mgr;
> +	struct device_node *mgr_node;
> +
> +	mgr_node = of_parse_phandle(node, mgr_property, 0);
> +
> +	if (!mgr_node) {
> +		*ret = -ENODEV;
> +		return NULL;

Could IS_ERR_OR_NULL() and friends be used to get reasonable calling
convention?

Thanks,	
									Pavel

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