[PATCH V3] phy: nop-phy: Enable reset-gpios support

[Adam Ford <aford173@gmail.com>]

Some usb-nop-xceiv devices use a gpio to put them in and
out of reset.  Add a reset function to put them into that
state.  This is similar to how Linux handles the
usb-nop-xceiv driver.

Signed-off-by: Adam Ford <aford173@gmail.com>
---
V3:  Encapsulate the nop_phy_ops reference to nop_phy_reset
     in an if-def so it doesn't appear when DM_GPIO is not
     enabled.

V2:  Only use the GPIO functions when DM_GPIO is enabled
     Add error handling so if the GPIO fails, it will shutdown
     the clocks and return with the error code.
     Call nop_phy_reset() instead of repeating the same code.

diff --git a/drivers/phy/nop-phy.c b/drivers/phy/nop-phy.c
index 9f12ebc062..eac00953d3 100644
--- a/drivers/phy/nop-phy.c
+++ b/drivers/phy/nop-phy.c
@@ -10,17 +10,47 @@
 #include <dm/device.h>
 #include <dm/device_compat.h>
 #include <generic-phy.h>
+#include <asm-generic/gpio.h>
 
 struct nop_phy_priv {
 	struct clk_bulk bulk;
+#if CONFIG_IS_ENABLED(DM_GPIO)
+	struct gpio_desc reset_gpio;
+#endif
 };
 
+#if CONFIG_IS_ENABLED(DM_GPIO)
+static int nop_phy_reset(struct phy *phy)
+{
+	struct nop_phy_priv *priv = dev_get_priv(phy->dev);
+
+	/* Return if there is no gpio since it's optional */
+	if (!dm_gpio_is_valid(&priv->reset_gpio))
+		return 0;
+
+	return dm_gpio_set_value(&priv->reset_gpio, false);
+}
+#endif
+
 static int nop_phy_init(struct phy *phy)
 {
 	struct nop_phy_priv *priv = dev_get_priv(phy->dev);
+	int ret = 0;
+
+	if (CONFIG_IS_ENABLED(CLK)) {
+		ret = clk_enable_bulk(&priv->bulk);
+		if (ret)
+			return ret;
+	}
 
-	if (CONFIG_IS_ENABLED(CLK))
-		return clk_enable_bulk(&priv->bulk);
+	if (CONFIG_IS_ENABLED(DM_GPIO)) {
+		ret = nop_phy_reset(phy);
+		if (ret) {
+			if (CONFIG_IS_ENABLED(CLK))
+				clk_disable_bulk(&priv->bulk);
+			return ret;
+		}
+	}
 
 	return 0;
 }
@@ -38,6 +68,12 @@ static int nop_phy_probe(struct udevice *dev)
 		}
 	}
 
+	ret = gpio_request_by_name(dev, "reset-gpios", 0,
+				   &priv->reset_gpio,
+				   GPIOD_IS_OUT);
+	if (ret != -ENOENT)
+		return ret;
+
 	return 0;
 }
 
@@ -49,6 +85,9 @@ static const struct udevice_id nop_phy_ids[] = {
 
 static struct phy_ops nop_phy_ops = {
 	.init = nop_phy_init,
+#if CONFIG_IS_ENABLED(DM_GPIO)
+	.reset = nop_phy_reset,
+#endif
 };
 
 U_BOOT_DRIVER(nop_phy) = {
-- 
2.32.0