[PATCH v3 3/8] usb: cdns3-ti: move reg writes from probe into ->runtime_resume()

["Théo Lebrun" <theo.lebrun@bootlin.com>]

The hardware initialisation register write sequence is only used at
probe. Move it from being done at explicitely at probe to being done
implicitely by pm_runtime_get_sync() that calls ->runtime_resume().

Keep devicetree parsing in probe and add a new field in the private
struct to remember the USB2 refclk rate code computation result.

This opens the door to having the init sequence being executed later
down the road, at system-wide resume for example. This is NOT currently
happening because runtime PM is disabled at suspend without the
refcount being affected.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
 drivers/usb/cdns3/cdns3-ti.c | 90 +++++++++++++++++++++++++-------------------
 1 file changed, 52 insertions(+), 38 deletions(-)

diff --git a/drivers/usb/cdns3/cdns3-ti.c b/drivers/usb/cdns3/cdns3-ti.c
index 5945c4b1e11f..4c8a557e6a6f 100644
--- a/drivers/usb/cdns3/cdns3-ti.c
+++ b/drivers/usb/cdns3/cdns3-ti.c
@@ -57,6 +57,7 @@ struct cdns_ti {
 	unsigned vbus_divider:1;
 	struct clk *usb2_refclk;
 	struct clk *lpm_clk;
+	int usb2_refclk_rate_code;
 };
 
 static const int cdns_ti_rate_table[] = {	/* in KHZ */
@@ -90,10 +91,8 @@ static int cdns_ti_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct device_node *node = pdev->dev.of_node;
 	struct cdns_ti *data;
-	int error;
-	u32 reg;
-	int rate_code, i;
 	unsigned long rate;
+	int error, i;
 
 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
@@ -133,7 +132,9 @@ static int cdns_ti_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	rate_code = i;
+	data->usb2_refclk_rate_code = i;
+	data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
+	data->usb2_only = device_property_read_bool(dev, "ti,usb2-only");
 
 	pm_runtime_enable(dev);
 	error = pm_runtime_get_sync(dev);
@@ -142,40 +143,6 @@ static int cdns_ti_probe(struct platform_device *pdev)
 		goto err;
 	}
 
-	/* assert RESET */
-	reg = cdns_ti_readl(data, USBSS_W1);
-	reg &= ~USBSS_W1_PWRUP_RST;
-	cdns_ti_writel(data, USBSS_W1, reg);
-
-	/* set static config */
-	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
-	reg &= ~USBSS1_STATIC_PLL_REF_SEL_MASK;
-	reg |= rate_code << USBSS1_STATIC_PLL_REF_SEL_SHIFT;
-
-	reg &= ~USBSS1_STATIC_VBUS_SEL_MASK;
-	data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
-	if (data->vbus_divider)
-		reg |= 1 << USBSS1_STATIC_VBUS_SEL_SHIFT;
-
-	cdns_ti_writel(data, USBSS_STATIC_CONFIG, reg);
-	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
-
-	/* set USB2_ONLY mode if requested */
-	reg = cdns_ti_readl(data, USBSS_W1);
-	data->usb2_only = device_property_read_bool(dev, "ti,usb2-only");
-	if (data->usb2_only)
-		reg |= USBSS_W1_USB2_ONLY;
-
-	/* set default modestrap */
-	reg |= USBSS_W1_MODESTRAP_SEL;
-	reg &= ~USBSS_W1_MODESTRAP_MASK;
-	reg |= USBSS_MODESTRAP_MODE_NONE << USBSS_W1_MODESTRAP_SHIFT;
-	cdns_ti_writel(data, USBSS_W1, reg);
-
-	/* de-assert RESET */
-	reg |= USBSS_W1_PWRUP_RST;
-	cdns_ti_writel(data, USBSS_W1, reg);
-
 	error = of_platform_populate(node, NULL, NULL, dev);
 	if (error) {
 		dev_err(dev, "failed to create children: %d\n", error);
@@ -211,6 +178,52 @@ static void cdns_ti_remove(struct platform_device *pdev)
 	platform_set_drvdata(pdev, NULL);
 }
 
+static int cdns_ti_runtime_resume(struct device *dev)
+{
+	struct cdns_ti *data = dev_get_drvdata(dev);
+	u32 reg;
+
+	/* assert RESET */
+	reg = cdns_ti_readl(data, USBSS_W1);
+	reg &= ~USBSS_W1_PWRUP_RST;
+	cdns_ti_writel(data, USBSS_W1, reg);
+
+	/* set static config */
+	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
+	reg &= ~USBSS1_STATIC_PLL_REF_SEL_MASK;
+	reg |= data->usb2_refclk_rate_code << USBSS1_STATIC_PLL_REF_SEL_SHIFT;
+
+	reg &= ~USBSS1_STATIC_VBUS_SEL_MASK;
+
+	if (data->vbus_divider)
+		reg |= 1 << USBSS1_STATIC_VBUS_SEL_SHIFT;
+
+	cdns_ti_writel(data, USBSS_STATIC_CONFIG, reg);
+	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
+
+	/* set USB2_ONLY mode if requested */
+	reg = cdns_ti_readl(data, USBSS_W1);
+
+	if (data->usb2_only)
+		reg |= USBSS_W1_USB2_ONLY;
+
+	/* set default modestrap */
+	reg |= USBSS_W1_MODESTRAP_SEL;
+	reg &= ~USBSS_W1_MODESTRAP_MASK;
+	reg |= USBSS_MODESTRAP_MODE_NONE << USBSS_W1_MODESTRAP_SHIFT;
+	cdns_ti_writel(data, USBSS_W1, reg);
+
+	/* de-assert RESET */
+	reg |= USBSS_W1_PWRUP_RST;
+	cdns_ti_writel(data, USBSS_W1, reg);
+
+	return 0;
+}
+
+static const struct dev_pm_ops cdns_ti_pm_ops = {
+	RUNTIME_PM_OPS(NULL, cdns_ti_runtime_resume, NULL)
+};
+
 static const struct of_device_id cdns_ti_of_match[] = {
 	{ .compatible = "ti,j721e-usb", },
 	{ .compatible = "ti,am64-usb", },
@@ -224,6 +237,7 @@ static struct platform_driver cdns_ti_driver = {
 	.driver		= {
 		.name	= "cdns3-ti",
 		.of_match_table	= cdns_ti_of_match,
+		.pm	= pm_ptr(&cdns_ti_pm_ops),
 	},
 };
 

-- 
2.43.2