[PATCH v3 3/5] usb: dwc3-am62: Fix PHY core voltage selection

[Roger Quadros]

TRM information is outdated and design team has confirmed
that PHY_CORE_VOLTAGE should be 0 irrespective of
VDD_CORE voltage.

Signed-off-by: Roger Quadros <rogerq@xxxxxxxxxx>
---
Changelog:

v3: no change

v2: no change
	https://lore.kernel.org/all/20240205141221.56076-4-rogerq@xxxxxxxxxx/

v1: https://lore.kernel.org/all/20240201121220.5523-4-rogerq@xxxxxxxxxx/
---
 drivers/usb/dwc3/dwc3-am62.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
index 600ba9cfefea..af1ce934e7fb 100644
--- a/drivers/usb/dwc3/dwc3-am62.c
+++ b/drivers/usb/dwc3/dwc3-am62.c
@@ -97,7 +97,8 @@
 #define USBSS_VBUS_STAT_SESSVALID	BIT(2)
 #define USBSS_VBUS_STAT_VBUSVALID	BIT(0)
 
-/* Mask for PHY PLL REFCLK */
+/* USB_PHY_CTRL register bits in CTRL_MMR */
+#define PHY_CORE_VOLTAGE_MASK	BIT(31)
 #define PHY_PLL_REFCLK_MASK	GENMASK(3, 0)
 
 #define DWC3_AM62_AUTOSUSPEND_DELAY	100
@@ -162,6 +163,13 @@ static int phy_syscon_pll_refclk(struct dwc3_am62 *am62)
 
 	am62->offset = args.args[0];
 
+	/* Core voltage. PHY_CORE_VOLTAGE bit Recommended to be 0 always */
+	ret = regmap_update_bits(am62->syscon, am62->offset, PHY_CORE_VOLTAGE_MASK, 0);
+	if (ret) {
+		dev_err(dev, "failed to set phy core voltage\n");
+		return ret;
+	}
+
 	ret = regmap_update_bits(am62->syscon, am62->offset, PHY_PLL_REFCLK_MASK, am62->rate_code);
 	if (ret) {
 		dev_err(dev, "failed to set phy pll reference clock rate\n");

-- 
2.34.1