phy: rockchip-inno-usb2: Implement clock operations for usb2phy clock

This clock doesn't seem needed but appears in a phandle list used by
ehci-generic.c to bulk enable it. The phandle list comes from linux,
where it is needed for suspend/resume to work [1].

My tests give the same results with or without this patch, but Marek
Vasut found it weird to declare an empty clk_ops [2].

So I adapted the code from linux 6.1-rc8 so that it hopefully works
if it ever has some user. For now, without real use, it seems to
at least not give any errors when called.

Link: [1] https://lkml.kernel.org/lkml/1731551.Q6cHK6n5ZM@phil/T/
      [2] https://patchwork.ozlabs.org/project/uboot/patch/Y5IWpjYLB4aXMy9o@localhost/

Cc: Simon Glass <sjg@chromium.org>
Cc: Philipp Tomsich <philipp.tomsich@vrull.eu>
Cc: Kever Yang <kever.yang@rock-chips.com>
Cc: Lukasz Majewski <lukma@denx.de>
Cc: Sean Anderson <seanga2@gmail.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Christoph Fritz <chf.fritz@googlemail.com>
Cc: Jagan Teki <jagan@amarulasolutions.com>

Signed-off-by: Xavier Drudis Ferran <xdrudis@tinet.cat>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com> # rk3399, rk3328, rv1126

drivers/phy/rockchip/phy-rockchip-inno-usb2.c

@@ -56,6 +56,7 @@ struct rockchip_usb2phy_port_cfg {
 
 struct rockchip_usb2phy_cfg {
 	unsigned int reg;
+	struct usb2phy_reg	clkout_ctl;
 	const struct rockchip_usb2phy_port_cfg port_cfgs[USB2PHY_NUM_PORTS];
 };
 
@@ -77,6 +78,18 @@ static inline int property_enable(void *reg_base,
 	return writel(val, reg_base + reg->offset);
 }
 
+static inline bool property_enabled(void *reg_base,
+				    const struct usb2phy_reg *reg)
+{
+	unsigned int tmp, orig;
+	unsigned int mask = GENMASK(reg->bitend, reg->bitstart);
+
+	orig = readl(reg_base + reg->offset);
+
+	tmp = (orig & mask) >> reg->bitstart;
+	return tmp != reg->disable;
+}
+
 static const
 struct rockchip_usb2phy_port_cfg *us2phy_get_port(struct phy *phy)
 {
@@ -169,7 +182,63 @@ static struct phy_ops rockchip_usb2phy_ops = {
 	.of_xlate = rockchip_usb2phy_of_xlate,
 };
 
+/**
+ * round_rate() - Adjust a rate to the exact rate a clock can provide.
+ * @clk:	The clock to manipulate.
+ * @rate:	Desidered clock rate in Hz.
+ *
+ * Return: rounded rate in Hz, or -ve error code.
+ */
+ulong rockchip_usb2phy_clk_round_rate(struct clk *clk, ulong rate)
+{
+	return 480000000;
+}
+
+/**
+ * enable() - Enable a clock.
+ * @clk:	The clock to manipulate.
+ *
+ * Return: zero on success, or -ve error code.
+ */
+int rockchip_usb2phy_clk_enable(struct clk *clk)
+{
+	struct udevice *parent = dev_get_parent(clk->dev);
+	struct rockchip_usb2phy *priv = dev_get_priv(parent);
+	const struct rockchip_usb2phy_cfg *phy_cfg = priv->phy_cfg;
+
+	/* turn on 480m clk output if it is off */
+	if (!property_enabled(priv->reg_base, &phy_cfg->clkout_ctl)) {
+		property_enable(priv->reg_base, &phy_cfg->clkout_ctl, true);
+
+		/* waiting for the clk become stable */
+		usleep_range(1200, 1300);
+	}
+
+	return 0;
+}
+
+/**
+ * disable() - Disable a clock.
+ * @clk:	The clock to manipulate.
+ *
+ * Return: zero on success, or -ve error code.
+ */
+int rockchip_usb2phy_clk_disable(struct clk *clk)
+{
+	struct udevice *parent = dev_get_parent(clk->dev);
+	struct rockchip_usb2phy *priv = dev_get_priv(parent);
+	const struct rockchip_usb2phy_cfg *phy_cfg = priv->phy_cfg;
+
+	/* turn off 480m clk output */
+	property_enable(priv->reg_base, &phy_cfg->clkout_ctl, false);
+
+	return 0;
+}
+
 static struct clk_ops rockchip_usb2phy_clk_ops = {
+	.enable = rockchip_usb2phy_clk_enable,
+	.disable = rockchip_usb2phy_clk_disable,
+	.round_rate = rockchip_usb2phy_clk_round_rate
 };
 
 static int rockchip_usb2phy_probe(struct udevice *dev)
@@ -255,8 +324,11 @@ static int rockchip_usb2phy_bind(struct udevice *dev)
 	}
 
 	node = dev_ofnode(dev);
-	name = ofnode_get_name(node);
+	name = "clk_usbphy_480m";
-	dev_dbg(dev, "clk for node %s\n", name);
+	dev_read_string_index(dev, "clock-output-names", 0, &name);
+
+	dev_dbg(dev, "clk %s for node %s\n", name, ofnode_get_name(node));
+
 	ret = device_bind_driver_to_node(dev, "rockchip_usb2phy_clock",
 					 name, node, &usb2phy_dev);
 	if (ret) {
@@ -276,6 +348,7 @@ bind_fail:
 static const struct rockchip_usb2phy_cfg rk3399_usb2phy_cfgs[] = {
 	{
 		.reg		= 0xe450,
+		.clkout_ctl	= { 0xe450, 4, 4, 1, 0 },
 		.port_cfgs	= {
 			[USB2PHY_PORT_OTG] = {
 				.phy_sus	= { 0xe454, 1, 0, 2, 1 },
@@ -297,6 +370,7 @@ static const struct rockchip_usb2phy_cfg rk3399_usb2phy_cfgs[] = {
 	},
 	{
 		.reg		= 0xe460,
+		.clkout_ctl	= { 0xe460, 4, 4, 1, 0 },
 		.port_cfgs	= {
 			[USB2PHY_PORT_OTG] = {
 				.phy_sus        = { 0xe464, 1, 0, 2, 1 },
@@ -322,6 +396,7 @@ static const struct rockchip_usb2phy_cfg rk3399_usb2phy_cfgs[] = {
 static const struct rockchip_usb2phy_cfg rk3568_phy_cfgs[] = {
 	{
 		.reg		= 0xfe8a0000,
+		.clkout_ctl	= { 0x0008, 4, 4, 1, 0 },
 		.port_cfgs	= {
 			[USB2PHY_PORT_OTG] = {
 				.phy_sus	= { 0x0000, 8, 0, 0x052, 0x1d1 },
@@ -347,6 +422,7 @@ static const struct rockchip_usb2phy_cfg rk3568_phy_cfgs[] = {
 	},
 	{
 		.reg		= 0xfe8b0000,
+		.clkout_ctl	= { 0x0008, 4, 4, 1, 0 },
 		.port_cfgs	= {
 			[USB2PHY_PORT_OTG] = {
 				.phy_sus	= { 0x0000, 8, 0, 0x1d2, 0x1d1 },