usb: dwc3: Add dwc3_of_parse() to get quirks information from DT

Add a new function that read quirk and configuration information from the
DT. The goal is to allow platforms using their own version of DWC3 driver
to migrate to the generic DWC3 driver.
The function is adapted from the function dwc3_get_properties() in the
linux dwc3 driver introduced in commit c5ac6116db35d.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index bb3f9d2..5fe5bfa 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -888,6 +888,71 @@
 #endif
 
 #if CONFIG_IS_ENABLED(DM_USB)
+void dwc3_of_parse(struct dwc3 *dwc)
+{
+	const u8 *tmp;
+	struct udevice *dev = dwc->dev;
+	u8 lpm_nyet_threshold;
+	u8 tx_de_emphasis;
+	u8 hird_threshold;
+
+	/* default to highest possible threshold */
+	lpm_nyet_threshold = 0xff;
+
+	/* default to -3.5dB de-emphasis */
+	tx_de_emphasis = 1;
+
+	/*
+	 * default to assert utmi_sleep_n and use maximum allowed HIRD
+	 * threshold value of 0b1100
+	 */
+	hird_threshold = 12;
+
+	dwc->has_lpm_erratum = dev_read_bool(dev,
+				"snps,has-lpm-erratum");
+	tmp = dev_read_u8_array_ptr(dev, "snps,lpm-nyet-threshold", 1);
+	if (tmp)
+		lpm_nyet_threshold = *tmp;
+
+	dwc->is_utmi_l1_suspend = dev_read_bool(dev,
+				"snps,is-utmi-l1-suspend");
+	tmp = dev_read_u8_array_ptr(dev, "snps,hird-threshold", 1);
+	if (tmp)
+		hird_threshold = *tmp;
+
+	dwc->disable_scramble_quirk = dev_read_bool(dev,
+				"snps,disable_scramble_quirk");
+	dwc->u2exit_lfps_quirk = dev_read_bool(dev,
+				"snps,u2exit_lfps_quirk");
+	dwc->u2ss_inp3_quirk = dev_read_bool(dev,
+				"snps,u2ss_inp3_quirk");
+	dwc->req_p1p2p3_quirk = dev_read_bool(dev,
+				"snps,req_p1p2p3_quirk");
+	dwc->del_p1p2p3_quirk = dev_read_bool(dev,
+				"snps,del_p1p2p3_quirk");
+	dwc->del_phy_power_chg_quirk = dev_read_bool(dev,
+				"snps,del_phy_power_chg_quirk");
+	dwc->lfps_filter_quirk = dev_read_bool(dev,
+				"snps,lfps_filter_quirk");
+	dwc->rx_detect_poll_quirk = dev_read_bool(dev,
+				"snps,rx_detect_poll_quirk");
+	dwc->dis_u3_susphy_quirk = dev_read_bool(dev,
+				"snps,dis_u3_susphy_quirk");
+	dwc->dis_u2_susphy_quirk = dev_read_bool(dev,
+				"snps,dis_u2_susphy_quirk");
+	dwc->tx_de_emphasis_quirk = dev_read_bool(dev,
+				"snps,tx_de_emphasis_quirk");
+	tmp = dev_read_u8_array_ptr(dev, "snps,tx_de_emphasis", 1);
+	if (tmp)
+		tx_de_emphasis = *tmp;
+
+	dwc->lpm_nyet_threshold = lpm_nyet_threshold;
+	dwc->tx_de_emphasis = tx_de_emphasis;
+
+	dwc->hird_threshold = hird_threshold
+		| (dwc->is_utmi_l1_suspend << 4);
+}
+
 int dwc3_init(struct dwc3 *dwc)
 {
 	int ret;