Re: [PATCH 3/3] arm64: dts: freescale: imx95-toradex-smarc: Use gpio-hog for WIFI_UART_EN

[Frank Li <Frank.li@nxp.com>]

On Wed, Mar 25, 2026 at 07:10:57PM +0100, Francesco Dolcini wrote:
> On Wed, Mar 25, 2026 at 10:54:46AM -0400, Frank Li wrote:
> > On Wed, Mar 25, 2026 at 12:55:11PM +0100, Franz Schnyder wrote:
> > > From: Franz Schnyder <franz.schnyder@toradex.com>
> > >
> > > On the Toradex SMARC iMX95, the WiFi UART signals are shared with the
> > > JTAG. The WIFI_UART_EN signal is used to select between these
> > > two functions.
> > >
> > > Configure the signal as gpio-hog and drive it high to select the UART
> > > function by default. Add a label to override the hog in derived
> > > device trees.
> >
> > gpio hog have problem about probe order, are you sure gpio device probe
> > before pcie?
>
> This is not about PCIe, we are talking about UART here. Specifically the
> module is a combo Wi-Fi/BT device, with Wi-Fi over SDIO, and BT over
> UART from NXP.
>
> In any case, this DT is going to be used also by the boot firmware that will
> configure the GPIO hog way before the Linux driver probes.

Commit message need show it is safe.

Frank

>
> The DT files from the Linux kernel are used also by other projects.
>
> > I have not seen any place refer to wifi_uart_en.
>
> There is none (as of now). This is there to make it easier for a user
> that needs access to debug to adjust this node enabling the JTAG
> functionality.
>
> Francesco
>