usb: phy: samsung: Consolidate reference clock rate handling

This patch cleans up handling of reference clock rate in Samsung USB PHY
drivers. It is mostly a cosmetic change but improves error handling in
case of failing to get reference clock or invalid clock rate.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/phy/phy-samsung-usb.c

@@ -162,73 +162,93 @@ int samsung_usbphy_set_type(struct usb_phy *phy,
 }
 EXPORT_SYMBOL_GPL(samsung_usbphy_set_type);
 
-/*
- * Returns reference clock frequency selection value
- */
-int samsung_usbphy_get_refclk_freq(struct samsung_usbphy *sphy)
+int samsung_usbphy_rate_to_clksel_64xx(struct samsung_usbphy *sphy,
+							unsigned long rate)
 {
-	struct clk *ref_clk;
-	int refclk_freq = 0;
+	unsigned int clksel;
 
-	/*
-	 * In exynos5250 USB host and device PHY use
-	 * external crystal clock XXTI
-	 */
-	if (sphy->drv_data->cpu_type == TYPE_EXYNOS5250)
-		ref_clk = clk_get(sphy->dev, "ext_xtal");
-	else
-		ref_clk = clk_get(sphy->dev, "xusbxti");
-	if (IS_ERR(ref_clk)) {
-		dev_err(sphy->dev, "Failed to get reference clock\n");
-		return PTR_ERR(ref_clk);
+	switch (rate) {
+	case 12 * MHZ:
+		clksel = PHYCLK_CLKSEL_12M;
+		break;
+	case 24 * MHZ:
+		clksel = PHYCLK_CLKSEL_24M;
+		break;
+	case 48 * MHZ:
+		clksel = PHYCLK_CLKSEL_48M;
+		break;
+	default:
+		dev_err(sphy->dev,
+			"Invalid reference clock frequency: %lu\n", rate);
+		return -EINVAL;
 	}
 
-	if (sphy->drv_data->cpu_type == TYPE_EXYNOS5250) {
-		/* set clock frequency for PLL */
-		switch (clk_get_rate(ref_clk)) {
+	return clksel;
+}
+EXPORT_SYMBOL_GPL(samsung_usbphy_rate_to_clksel_64xx);
+
+int samsung_usbphy_rate_to_clksel_4x12(struct samsung_usbphy *sphy,
+							unsigned long rate)
+{
+	unsigned int clksel;
+
+	switch (rate) {
 	case 9600 * KHZ:
-			refclk_freq = FSEL_CLKSEL_9600K;
+		clksel = FSEL_CLKSEL_9600K;
 		break;
 	case 10 * MHZ:
-			refclk_freq = FSEL_CLKSEL_10M;
+		clksel = FSEL_CLKSEL_10M;
 		break;
 	case 12 * MHZ:
-			refclk_freq = FSEL_CLKSEL_12M;
+		clksel = FSEL_CLKSEL_12M;
 		break;
 	case 19200 * KHZ:
-			refclk_freq = FSEL_CLKSEL_19200K;
+		clksel = FSEL_CLKSEL_19200K;
 		break;
 	case 20 * MHZ:
-			refclk_freq = FSEL_CLKSEL_20M;
-			break;
-		case 50 * MHZ:
-			refclk_freq = FSEL_CLKSEL_50M;
-			break;
-		case 24 * MHZ:
-		default:
-			/* default reference clock */
-			refclk_freq = FSEL_CLKSEL_24M;
-			break;
-		}
-	} else {
-		switch (clk_get_rate(ref_clk)) {
-		case 12 * MHZ:
-			refclk_freq = PHYCLK_CLKSEL_12M;
+		clksel = FSEL_CLKSEL_20M;
 		break;
 	case 24 * MHZ:
-			refclk_freq = PHYCLK_CLKSEL_24M;
+		clksel = FSEL_CLKSEL_24M;
 		break;
-		case 48 * MHZ:
-			refclk_freq = PHYCLK_CLKSEL_48M;
+	case 50 * MHZ:
+		clksel = FSEL_CLKSEL_50M;
 		break;
 	default:
-			if (sphy->drv_data->cpu_type == TYPE_S3C64XX)
-				refclk_freq = PHYCLK_CLKSEL_48M;
-			else
-				refclk_freq = PHYCLK_CLKSEL_24M;
-			break;
+		dev_err(sphy->dev,
+			"Invalid reference clock frequency: %lu\n", rate);
+		return -EINVAL;
 	}
+
+	return clksel;
+}
+EXPORT_SYMBOL_GPL(samsung_usbphy_rate_to_clksel_4x12);
+
+/*
+ * Returns reference clock frequency selection value
+ */
+int samsung_usbphy_get_refclk_freq(struct samsung_usbphy *sphy)
+{
+	struct clk *ref_clk;
+	unsigned long rate;
+	int refclk_freq;
+
+	/*
+	 * In exynos5250 USB host and device PHY use
+	 * external crystal clock XXTI
+	 */
+	if (sphy->drv_data->cpu_type == TYPE_EXYNOS5250)
+		ref_clk = clk_get(sphy->dev, "ext_xtal");
+	else
+		ref_clk = clk_get(sphy->dev, "xusbxti");
+	if (IS_ERR(ref_clk)) {
+		dev_err(sphy->dev, "Failed to get reference clock\n");
+		return PTR_ERR(ref_clk);
 	}
+
+	rate = clk_get_rate(ref_clk);
+	refclk_freq = sphy->drv_data->rate_to_clksel(sphy, rate);
+
 	clk_put(ref_clk);
 
 	return refclk_freq;

drivers/usb/phy/phy-samsung-usb.h

@@ -244,6 +244,8 @@ enum samsung_cpu_type {
 	TYPE_EXYNOS5250,
 };
 
+struct samsung_usbphy;
+
 /*
  * struct samsung_usbphy_drvdata - driver data for various SoC variants
  * @cpu_type: machine identifier
@@ -268,6 +270,7 @@ struct samsung_usbphy_drvdata {
 	int hostphy_en_mask;
 	u32 devphy_reg_offset;
 	u32 hostphy_reg_offset;
+	int (*rate_to_clksel)(struct samsung_usbphy *, unsigned long);
 };
 
 /*
@@ -325,3 +328,7 @@ extern void samsung_usbphy_cfg_sel(struct samsung_usbphy *sphy);
 extern int samsung_usbphy_set_type(struct usb_phy *phy,
 					enum samsung_usb_phy_type phy_type);
 extern int samsung_usbphy_get_refclk_freq(struct samsung_usbphy *sphy);
+extern int samsung_usbphy_rate_to_clksel_64xx(struct samsung_usbphy *sphy,
+							unsigned long rate);
+extern int samsung_usbphy_rate_to_clksel_4x12(struct samsung_usbphy *sphy,
+							unsigned long rate);

drivers/usb/phy/phy-samsung-usb2.c

@@ -408,7 +408,10 @@ static int samsung_usb2phy_probe(struct platform_device *pdev)
 	sphy->phy.label		= "samsung-usb2phy";
 	sphy->phy.init		= samsung_usb2phy_init;
 	sphy->phy.shutdown	= samsung_usb2phy_shutdown;
+
 	sphy->ref_clk_freq = samsung_usbphy_get_refclk_freq(sphy);
+	if (sphy->ref_clk_freq < 0)
+		return -EINVAL;
 
 	sphy->phy.otg		= otg;
 	sphy->phy.otg->phy	= &sphy->phy;
@@ -438,18 +441,21 @@ static int samsung_usb2phy_remove(struct platform_device *pdev)
 static const struct samsung_usbphy_drvdata usb2phy_s3c64xx = {
 	.cpu_type		= TYPE_S3C64XX,
 	.devphy_en_mask		= S3C64XX_USBPHY_ENABLE,
+	.rate_to_clksel		= samsung_usbphy_rate_to_clksel_64xx,
 };
 
 static const struct samsung_usbphy_drvdata usb2phy_exynos4 = {
 	.cpu_type		= TYPE_EXYNOS4210,
 	.devphy_en_mask		= EXYNOS_USBPHY_ENABLE,
 	.hostphy_en_mask	= EXYNOS_USBPHY_ENABLE,
+	.rate_to_clksel		= samsung_usbphy_rate_to_clksel_64xx,
 };
 
 static struct samsung_usbphy_drvdata usb2phy_exynos5 = {
 	.cpu_type		= TYPE_EXYNOS5250,
 	.hostphy_en_mask	= EXYNOS_USBPHY_ENABLE,
 	.hostphy_reg_offset	= EXYNOS_USBHOST_PHY_CTRL_OFFSET,
+	.rate_to_clksel		= samsung_usbphy_rate_to_clksel_4x12,
 };
 
 #ifdef CONFIG_OF

drivers/usb/phy/phy-samsung-usb3.c

@@ -274,7 +274,10 @@ static int samsung_usb3phy_probe(struct platform_device *pdev)
 	sphy->phy.init		= samsung_usb3phy_init;
 	sphy->phy.shutdown	= samsung_usb3phy_shutdown;
 	sphy->drv_data		= samsung_usbphy_get_driver_data(pdev);
+
 	sphy->ref_clk_freq = samsung_usbphy_get_refclk_freq(sphy);
+	if (sphy->ref_clk_freq < 0)
+		return -EINVAL;
 
 	spin_lock_init(&sphy->lock);
 
@@ -300,6 +303,7 @@ static int samsung_usb3phy_remove(struct platform_device *pdev)
 static struct samsung_usbphy_drvdata usb3phy_exynos5 = {
 	.cpu_type		= TYPE_EXYNOS5250,
 	.devphy_en_mask		= EXYNOS_USBPHY_ENABLE,
+	.rate_to_clksel		= samsung_usbphy_rate_to_clksel_4x12,
 };
 
 #ifdef CONFIG_OF