Re: [PATCH 5/6] mach-snapdragon: of_fixup: set dr_mode for RB1/2 boards

[Neil Armstrong <neil.armstrong@linaro.org>]

On 09/04/2025 19:17, Caleb Connolly wrote:
> The RB1 and RB2 have a single USB controller which is manually muxed
> between a type-c port and an internal USB hub via a DIP switch. OTG is
> supported in Linux, but the DWC3 driver in U-Boot can only handle a
> single mode, and defaults to peripheral mode.
> 
> We did hack around this on the RB2, but the RB1 got left out.
> 
> Now that we can fix up the live tree before devices are bound, drop the
> DTS hacks and do the fixup at runtime instead.
> 
> Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
> ---
>   arch/arm/dts/qrb4210-rb2-u-boot.dtsi |  6 ------
>   arch/arm/mach-snapdragon/of_fixup.c  | 28 ++++++++++++++--------------
>   2 files changed, 14 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/arm/dts/qrb4210-rb2-u-boot.dtsi b/arch/arm/dts/qrb4210-rb2-u-boot.dtsi
> deleted file mode 100644
> index 7d1375f38c44d7bd54c022fa3d390f666a35d6ee..0000000000000000000000000000000000000000
> --- a/arch/arm/dts/qrb4210-rb2-u-boot.dtsi
> +++ /dev/null
> @@ -1,6 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -
> -/* This is usually OTG but U-Boot doesn't support that properly */
> -&usb_dwc3 {
> -	dr_mode = "host";
> -};
> diff --git a/arch/arm/mach-snapdragon/of_fixup.c b/arch/arm/mach-snapdragon/of_fixup.c
> index b39036e8e0890fdf834a0dfe6966ef3dd365f3d2..62b329e2c90d7e0a374838968ab5707333edbf03 100644
> --- a/arch/arm/mach-snapdragon/of_fixup.c
> +++ b/arch/arm/mach-snapdragon/of_fixup.c
> @@ -98,8 +98,21 @@ static int fixup_qcom_dwc3(struct device_node *glue_np)
>   		log_err("Failed to set 'maximum-speed' property: %d\n", ret);
>   		return ret;
>   	}
>   
> +	/*
> +	 * The RB1/2 boards only have a single USB controller and it's muxed between the type-C port
> +	 * and a USB hub. Since we can't do OTG in U-Boot properly we prefer to put it into host mode.
> +	 */
> +	if (of_device_is_compatible(gd->of_root, "qcom,qrb4210-rb2", NULL, NULL) ||
> +	    of_device_is_compatible(gd->of_root, "qcom,qrb2210-rb1", NULL, NULL)) {
> +		ret = of_write_prop(dwc3, "dr_mode", sizeof("host"), "host");
> +		if (ret) {
> +			log_err("Failed to set 'dr_mode' property: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
>   	return 0;
>   }
>   
>   static void fixup_usb_nodes(void)
> @@ -162,21 +175,8 @@ static int qcom_of_fixup_nodes(void)
>   }
>   
>   EVENT_SPY_SIMPLE(EVT_OF_LIVE_INIT, qcom_of_fixup_nodes);
>   
> -int ft_board_setup(void *blob, struct bd_info __maybe_unused *bd)
> +int ft_board_setup(void __maybe_unused *blob, struct bd_info __maybe_unused *bd)
>   {
> -	struct fdt_header *fdt = blob;
> -	int node;
> -
> -	/* On RB1/2 we need to fix-up the dr_mode */
> -	if (!fdt_node_check_compatible(fdt, 0, "qcom,qrb4210-rb2") ||
> -	    !fdt_node_check_compatible(fdt, 0, "qcom,qrb2210-rb1")) {
> -		fdt_for_each_node_by_compatible(node, blob, 0, "snps,dwc3") {
> -			log_debug("%s: Setting 'dr_mode' to OTG\n", fdt_get_name(blob, node, NULL));
> -			fdt_setprop_string(fdt, node, "dr_mode", "otg");
> -			break;
> -		}
> -	}
> -
>   	return 0;
>   }
> 

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>