usb: phy: omap-usb3: Improve DPLL parameter lookup code

Use a mapping table (dpll_map) to match the possible system clock rates
to the appropriate DPLL parameters.

Introduce a function "omap_usb3_get_dpll_params()" that will
return the matching DPLL parameters for the given clock rate.

Also, bail out on phy init if DPLL locking fails.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

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

@@ -27,7 +27,6 @@
 #include <linux/delay.h>
 #include <linux/usb/omap_control_usb.h>
 
-#define	NUM_SYS_CLKS		6
 #define	PLL_STATUS		0x00000004
 #define	PLL_GO			0x00000008
 #define	PLL_CONFIGURATION1	0x0000000C
@@ -57,26 +56,32 @@
  */
 # define PLL_IDLE_TIME  100;
 
-enum sys_clk_rate {
-	CLK_RATE_UNDEFINED = -1,
-	CLK_RATE_12MHZ,
-	CLK_RATE_16MHZ,
-	CLK_RATE_19MHZ,
-	CLK_RATE_20MHZ,
-	CLK_RATE_26MHZ,
-	CLK_RATE_38MHZ
+struct usb_dpll_map {
+	unsigned long rate;
+	struct usb_dpll_params params;
 };
 
-static struct usb_dpll_params omap_usb3_dpll_params[NUM_SYS_CLKS] = {
-	{1250, 5, 4, 20, 0},		/* 12 MHz */
-	{3125, 20, 4, 20, 0},		/* 16.8 MHz */
-	{1172, 8, 4, 20, 65537},	/* 19.2 MHz */
-	{1000, 7, 4, 10, 0},            /* 20 MHz */
-	{1250, 12, 4, 20, 0},		/* 26 MHz */
-	{3125, 47, 4, 20, 92843},	/* 38.4 MHz */
-
+static struct usb_dpll_map dpll_map[] = {
+	{12000000, {1250, 5, 4, 20, 0} },	/* 12 MHz */
+	{16800000, {3125, 20, 4, 20, 0} },	/* 16.8 MHz */
+	{19200000, {1172, 8, 4, 20, 65537} },	/* 19.2 MHz */
+	{20000000, {1000, 7, 4, 10, 0} },	/* 20 MHz */
+	{26000000, {1250, 12, 4, 20, 0} },	/* 26 MHz */
+	{38400000, {3125, 47, 4, 20, 92843} },	/* 38.4 MHz */
 };
 
+static struct usb_dpll_params *omap_usb3_get_dpll_params(unsigned long rate)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(dpll_map); i++) {
+		if (rate == dpll_map[i].rate)
+			return &dpll_map[i].params;
+	}
+
+	return 0;
+}
+
 static int omap_usb3_suspend(struct usb_phy *x, int suspend)
 {
 	struct omap_usb *phy = phy_to_omapusb(x);
@@ -116,26 +121,6 @@ static int omap_usb3_suspend(struct usb_phy *x, int suspend)
 	return 0;
 }
 
-static inline enum sys_clk_rate __get_sys_clk_index(unsigned long rate)
-{
-	switch (rate) {
-	case 12000000:
-		return CLK_RATE_12MHZ;
-	case 16800000:
-		return CLK_RATE_16MHZ;
-	case 19200000:
-		return CLK_RATE_19MHZ;
-	case 20000000:
-		return CLK_RATE_20MHZ;
-	case 26000000:
-		return CLK_RATE_26MHZ;
-	case 38400000:
-		return CLK_RATE_38MHZ;
-	default:
-		return CLK_RATE_UNDEFINED;
-	}
-}
-
 static void omap_usb_dpll_relock(struct omap_usb *phy)
 {
 	u32		val;
@@ -155,39 +140,39 @@ static int omap_usb_dpll_lock(struct omap_usb *phy)
 {
 	u32			val;
 	unsigned long		rate;
-	enum sys_clk_rate	clk_index;
-
-	rate		= clk_get_rate(phy->sys_clk);
-	clk_index	= __get_sys_clk_index(rate);
+	struct usb_dpll_params *dpll_params;
 
-	if (clk_index == CLK_RATE_UNDEFINED) {
-		pr_err("dpll cannot be locked for sys clk freq:%luHz\n", rate);
+	rate = clk_get_rate(phy->sys_clk);
+	dpll_params = omap_usb3_get_dpll_params(rate);
+	if (!dpll_params) {
+		dev_err(phy->dev,
+			  "No DPLL configuration for %lu Hz SYS CLK\n", rate);
 		return -EINVAL;
 	}
 
 	val = omap_usb_readl(phy->pll_ctrl_base, PLL_CONFIGURATION1);
 	val &= ~PLL_REGN_MASK;
-	val |= omap_usb3_dpll_params[clk_index].n << PLL_REGN_SHIFT;
+	val |= dpll_params->n << PLL_REGN_SHIFT;
 	omap_usb_writel(phy->pll_ctrl_base, PLL_CONFIGURATION1, val);
 
 	val = omap_usb_readl(phy->pll_ctrl_base, PLL_CONFIGURATION2);
 	val &= ~PLL_SELFREQDCO_MASK;
-	val |= omap_usb3_dpll_params[clk_index].freq << PLL_SELFREQDCO_SHIFT;
+	val |= dpll_params->freq << PLL_SELFREQDCO_SHIFT;
 	omap_usb_writel(phy->pll_ctrl_base, PLL_CONFIGURATION2, val);
 
 	val = omap_usb_readl(phy->pll_ctrl_base, PLL_CONFIGURATION1);
 	val &= ~PLL_REGM_MASK;
-	val |= omap_usb3_dpll_params[clk_index].m << PLL_REGM_SHIFT;
+	val |= dpll_params->m << PLL_REGM_SHIFT;
 	omap_usb_writel(phy->pll_ctrl_base, PLL_CONFIGURATION1, val);
 
 	val = omap_usb_readl(phy->pll_ctrl_base, PLL_CONFIGURATION4);
 	val &= ~PLL_REGM_F_MASK;
-	val |= omap_usb3_dpll_params[clk_index].mf << PLL_REGM_F_SHIFT;
+	val |= dpll_params->mf << PLL_REGM_F_SHIFT;
 	omap_usb_writel(phy->pll_ctrl_base, PLL_CONFIGURATION4, val);
 
 	val = omap_usb_readl(phy->pll_ctrl_base, PLL_CONFIGURATION3);
 	val &= ~PLL_SD_MASK;
-	val |= omap_usb3_dpll_params[clk_index].sd << PLL_SD_SHIFT;
+	val |= dpll_params->sd << PLL_SD_SHIFT;
 	omap_usb_writel(phy->pll_ctrl_base, PLL_CONFIGURATION3, val);
 
 	omap_usb_dpll_relock(phy);
@@ -198,8 +183,12 @@ static int omap_usb_dpll_lock(struct omap_usb *phy)
 static int omap_usb3_init(struct usb_phy *x)
 {
 	struct omap_usb	*phy = phy_to_omapusb(x);
+	int ret;
+
+	ret = omap_usb_dpll_lock(phy);
+	if (ret)
+		return ret;
 
-	omap_usb_dpll_lock(phy);
 	omap_control_usb3_phy_power(phy->control_dev, 1);
 
 	return 0;