[PATCH v3 2/2] USB: xhci: add support for PWRON active high

[Francesco Dolcini <francesco@dolcini.it>]

From: Parth Pancholi <parth.pancholi@toradex.com>

Some PCIe-to-USB controllers such as TI's TUSB73x0 3.0 xHCI host
controller supports controlling the PWRONx polarity via the USB
control register (E0h). Add support for device tree property
ti,tusb7320-pwron-active-high which indicates PWRONx to be
active high and configure the E0h register accordingly.
This enables the software control for the TUSB73x0's PWRONx
outputs with an inverted polarity from the default configuration
which could be used as USB EN signals for the other hubs or devices.

Signed-off-by: Parth Pancholi <parth.pancholi@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
---
v3: no changes
v2: s/polarity-invert/active-high
---
 drivers/usb/host/xhci-pci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 91dccd25a551..4bdef01735eb 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -641,6 +641,9 @@ 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 (device_property_read_bool(&dev->dev, "ti,tusb7320-pwron-active-high"))
+		pci_clear_and_set_config_dword(dev, 0xE0, 0, 1 << 22);
+
 	return 0;
 
 put_usb3_hcd:
-- 
2.39.5