usb: host: dwc2: add clk support

Add support for clock with driver model.

This patch don't added dependency because when CONFIG_CLK
is not activated the clk function are stubbed.

Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c
index a8e6482..b1b79d0 100644
--- a/drivers/usb/host/dwc2.c
+++ b/drivers/usb/host/dwc2.c
@@ -5,14 +5,15 @@
  */
 
 #include <common.h>
+#include <clk.h>
 #include <cpu_func.h>
 #include <dm.h>
 #include <errno.h>
 #include <generic-phy.h>
-#include <usb.h>
 #include <malloc.h>
 #include <memalign.h>
 #include <phys2bus.h>
+#include <usb.h>
 #include <usbroothubdes.h>
 #include <wait_bit.h>
 #include <asm/io.h>
@@ -39,6 +40,7 @@
 	struct udevice *vbus_supply;
 #endif
 	struct phy phy;
+	struct clk_bulk clks;
 #else
 	uint8_t *aligned_buffer;
 	uint8_t *status_buffer;
@@ -1377,6 +1379,26 @@
 	return 0;
 }
 
+static int dwc2_clk_init(struct udevice *dev)
+{
+	struct dwc2_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	ret = clk_get_bulk(dev, &priv->clks);
+	if (ret == -ENOSYS || ret == -ENOENT)
+		return 0;
+	if (ret)
+		return ret;
+
+	ret = clk_enable_bulk(&priv->clks);
+	if (ret) {
+		clk_release_bulk(&priv->clks);
+		return ret;
+	}
+
+	return 0;
+}
+
 static int dwc2_usb_probe(struct udevice *dev)
 {
 	struct dwc2_priv *priv = dev_get_priv(dev);
@@ -1385,6 +1407,10 @@
 
 	bus_priv->desc_before_addr = true;
 
+	ret = dwc2_clk_init(dev);
+	if (ret)
+		return ret;
+
 	ret = dwc2_setup_phy(dev);
 	if (ret)
 		return ret;
@@ -1410,6 +1436,8 @@
 	dwc2_uninit_common(priv->regs);
 
 	reset_release_bulk(&priv->resets);
+	clk_disable_bulk(&priv->clks);
+	clk_release_bulk(&priv->clks);
 
 	return 0;
 }