Re: [PATCH 3/3] usb: xhci-pci: Put PWRON_POLARITY on a defined state

[Michal Pecio <michal.pecio@gmail.com>]

On Wed,  9 Sep 2026 09:58:42 -0300, Fabio Estevam wrote:
> Currently, TUSB73X0_PWRON_POLARITY is set when the
> "ti,pwron-active-high" is present.
>
> However, when "ti,pwron-active-high" is absent, its status could have
> been set previously by a bootloader or by a previous running kernel.

or by EEPROM.

Do they bother to put the chip in a wrong, non-default state at boot?

> To make the state of PWRON_POLARITY deterministic, always write it
> when the "ti,pwron-active-high" is present.

That wouldn't be too dangereous, but...

> Signed-off-by: Fabio Estevam <festevam@gmail.com>
> ---
>  drivers/usb/host/xhci-pci.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
> index 75aa679f7d79..833c55c3213a 100644
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -684,10 +684,16 @@ int xhci_pci_common_probe(struct pci_dev *dev, const struct pci_device_id *id)
>  	dma_set_max_seg_size(&dev->dev, UINT_MAX);
>  
>  	if (dev->vendor == PCI_VENDOR_ID_TI &&
> -	    dev->device == PCI_DEVICE_ID_TI_TUSB73X0)
> +	    dev->device == PCI_DEVICE_ID_TI_TUSB73X0) {
> +		u32 pwron_polarity = 0;
> +
>  		if (device_property_read_bool(&dev->dev, "ti,pwron-active-high"))
> -			pci_clear_and_set_config_dword(dev, TUSB73X0_USB_CTRL, 0,
> -						       TUSB73X0_PWRON_POLARITY);
> +			pwron_polarity = TUSB73X0_PWRON_POLARITY;
> +
> +		pci_clear_and_set_config_dword(dev, TUSB73X0_USB_CTRL,
> +					       TUSB73X0_PWRON_POLARITY,
> +					       pwron_polarity);
> +	}

... isn't device_property_present() missing here?

Also, I don't know those DT rules, but doesn't "ti,something" imply
that this must be a TI chip, no need to check IDs?

Regards,
Michal