[PATCH v4 4/6] usb: dwc3: dwc3-octeon: Move node parsing into driver probe

[Ladislav Michl <oss-lists@triops.cz>]

From: Ladislav Michl <ladis@linux-mips.org>

Parse and verify device tree node first, then setup UCTL bridge
using verified values. This avoids needless allocations
in case DT misconfiguration was found in the middle of setup.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
---
 CHANGES:
 - v2: if else block bracket according CodingStyle
 - v3: more descriptive commit message, power gpio parsing in probe too,
       checkpatch --strict passed
 - v4: move changes unrelated to parsing move into separate patches

 drivers/usb/dwc3/dwc3-octeon.c | 135 +++++++++++++++------------------
 1 file changed, 60 insertions(+), 75 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-octeon.c b/drivers/usb/dwc3/dwc3-octeon.c
index d6ad6fbb6c12..45726b39adab 100644
--- a/drivers/usb/dwc3/dwc3-octeon.c
+++ b/drivers/usb/dwc3/dwc3-octeon.c
@@ -261,69 +261,15 @@ static int dwc3_octeon_get_divider(void)
 }
 
 static int dwc3_octeon_setup(struct dwc3_octeon *octeon,
+			     int ref_clk_sel, int ref_clk_fsel, int mpll_mul,
 			     int power_gpio, int power_active_low)
 {
-	int i, div, mpll_mul, ref_clk_fsel, ref_clk_sel = 2;
-	u32 clock_rate;
 	u64 val;
+	int div;
 	struct device *dev = octeon->dev;
 	void __iomem *uctl_ctl_reg = octeon->base + USBDRD_UCTL_CTL;
 	void __iomem *uctl_host_cfg_reg = octeon->base + USBDRD_UCTL_HOST_CFG;
 
-	if (dev->of_node) {
-		const char *ss_clock_type;
-		const char *hs_clock_type;
-
-		i = of_property_read_u32(dev->of_node,
-					 "refclk-frequency", &clock_rate);
-		if (i) {
-			dev_err(dev, "No UCTL \"refclk-frequency\"\n");
-			return -EINVAL;
-		}
-		i = of_property_read_string(dev->of_node,
-					    "refclk-type-ss", &ss_clock_type);
-		if (i) {
-			dev_err(dev, "No UCTL \"refclk-type-ss\"\n");
-			return -EINVAL;
-		}
-		i = of_property_read_string(dev->of_node,
-					    "refclk-type-hs", &hs_clock_type);
-		if (i) {
-			dev_err(dev, "No UCTL \"refclk-type-hs\"\n");
-			return -EINVAL;
-		}
-		if (strcmp("dlmc_ref_clk0", ss_clock_type) == 0) {
-			if (strcmp(hs_clock_type, "dlmc_ref_clk0") == 0)
-				ref_clk_sel = 0;
-			else if (strcmp(hs_clock_type, "pll_ref_clk") == 0)
-				ref_clk_sel = 2;
-			else
-				dev_warn(dev, "Invalid HS clock type %s, using pll_ref_clk instead\n",
-					 hs_clock_type);
-		} else if (strcmp(ss_clock_type, "dlmc_ref_clk1") == 0) {
-			if (strcmp(hs_clock_type, "dlmc_ref_clk1") == 0)
-				ref_clk_sel = 1;
-			else if (strcmp(hs_clock_type, "pll_ref_clk") == 0)
-				ref_clk_sel = 3;
-			else {
-				dev_warn(dev, "Invalid HS clock type %s, using pll_ref_clk instead\n",
-					 hs_clock_type);
-				ref_clk_sel = 3;
-			}
-		} else
-			dev_warn(dev, "Invalid SS clock type %s, using dlmc_ref_clk0 instead\n",
-				 ss_clock_type);
-
-		if ((ref_clk_sel == 0 || ref_clk_sel == 1) &&
-		    (clock_rate != 100000000))
-			dev_warn(dev, "Invalid UCTL clock rate of %u, using 100000000 instead\n",
-				 clock_rate);
-
-	} else {
-		dev_err(dev, "No USB UCTL device node\n");
-		return -EINVAL;
-	}
-
 	/*
 	 * Step 1: Wait for all voltages to be stable...that surely
 	 *         happened before starting the kernel. SKIP
@@ -367,24 +313,6 @@ static int dwc3_octeon_setup(struct dwc3_octeon *octeon,
 	val &= ~USBDRD_UCTL_CTL_REF_CLK_SEL;
 	val |= FIELD_PREP(USBDRD_UCTL_CTL_REF_CLK_SEL, ref_clk_sel);
 
-	ref_clk_fsel = 0x07;
-	switch (clock_rate) {
-	default:
-		dev_warn(dev, "Invalid ref_clk %u, using 100000000 instead\n",
-			 clock_rate);
-		fallthrough;
-	case 100000000:
-		mpll_mul = 0x19;
-		if (ref_clk_sel < 2)
-			ref_clk_fsel = 0x27;
-		break;
-	case 50000000:
-		mpll_mul = 0x32;
-		break;
-	case 125000000:
-		mpll_mul = 0x28;
-		break;
-	}
 	val &= ~USBDRD_UCTL_CTL_REF_CLK_FSEL;
 	val |= FIELD_PREP(USBDRD_UCTL_CTL_REF_CLK_FSEL, ref_clk_fsel);
 
@@ -483,8 +411,64 @@ static int dwc3_octeon_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct device_node *node = dev->of_node;
 	struct dwc3_octeon *octeon;
+	const char *hs_clock_type, *ss_clock_type;
+	int ref_clk_sel, ref_clk_fsel, mpll_mul;
 	int power_active_low, power_gpio;
 	int err, len;
+	u32 clock_rate;
+
+	if (of_property_read_u32(node, "refclk-frequency", &clock_rate)) {
+		dev_err(dev, "No UCTL \"refclk-frequency\"\n");
+		return -EINVAL;
+	}
+	if (of_property_read_string(node, "refclk-type-ss", &ss_clock_type)) {
+		dev_err(dev, "No UCTL \"refclk-type-ss\"\n");
+		return -EINVAL;
+	}
+	if (of_property_read_string(node, "refclk-type-hs", &hs_clock_type)) {
+		dev_err(dev, "No UCTL \"refclk-type-hs\"\n");
+		return -EINVAL;
+	}
+
+	ref_clk_sel = 2;
+	if (strcmp("dlmc_ref_clk0", ss_clock_type) == 0) {
+		if (strcmp(hs_clock_type, "dlmc_ref_clk0") == 0)
+			ref_clk_sel = 0;
+		else if (strcmp(hs_clock_type, "pll_ref_clk"))
+			dev_warn(dev, "Invalid HS clock type %s, using pll_ref_clk instead\n",
+				 hs_clock_type);
+	} else if (strcmp(ss_clock_type, "dlmc_ref_clk1") == 0) {
+		if (strcmp(hs_clock_type, "dlmc_ref_clk1") == 0) {
+			ref_clk_sel = 1;
+		} else {
+			ref_clk_sel = 3;
+			if (strcmp(hs_clock_type, "pll_ref_clk"))
+				dev_warn(dev, "Invalid HS clock type %s, using pll_ref_clk instead\n",
+					 hs_clock_type);
+		}
+	} else {
+		dev_warn(dev, "Invalid SS clock type %s, using dlmc_ref_clk0 instead\n",
+			 ss_clock_type);
+	}
+
+	ref_clk_fsel = 0x07;
+	switch (clock_rate) {
+	default:
+		dev_warn(dev, "Invalid ref_clk %u, using 100000000 instead\n",
+			 clock_rate);
+		fallthrough;
+	case 100000000:
+		mpll_mul = 0x19;
+		if (ref_clk_sel < 2)
+			ref_clk_fsel = 0x27;
+		break;
+	case 50000000:
+		mpll_mul = 0x32;
+		break;
+	case 125000000:
+		mpll_mul = 0x28;
+		break;
+	}
 
 	power_gpio = DWC3_GPIO_POWER_NONE;
 	power_active_low = 0;
@@ -515,7 +499,8 @@ static int dwc3_octeon_probe(struct platform_device *pdev)
 	if (IS_ERR(octeon->base))
 		return PTR_ERR(octeon->base);
 
-	err = dwc3_octeon_setup(octeon, power_gpio, power_active_low);
+	err = dwc3_octeon_setup(octeon, ref_clk_sel, ref_clk_fsel, mpll_mul,
+				power_gpio, power_active_low);
 	if (err)
 		return err;
 
-- 
2.39.2