clk: keystone: add support for post divider register for main pll

Main PLL controller has post divider bits in a separate register in
pll controller. Use the value from this register instead of fixed
divider when available.
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>

Documentation/devicetree/bindings/clock/keystone-pll.txt

@@ -15,8 +15,8 @@ Required properties:
 - compatible : shall be "ti,keystone,main-pll-clock" or "ti,keystone,pll-clock"
 - clocks : parent clock phandle
 - reg - pll control0 and pll multipler registers
-- reg-names : control and multiplier. The multiplier is applicable only for
-		main pll clock
+- reg-names : control, multiplier and post-divider. The multiplier and
+		post-divider registers are applicable only for main pll clock
 - fixed-postdiv : fixed post divider value. If absent, use clkod register bits
 		for postdiv
 
@@ -25,8 +25,8 @@ Example:
 		#clock-cells = <0>;
 		compatible = "ti,keystone,main-pll-clock";
 		clocks = <&refclksys>;
-		reg = <0x02620350 4>, <0x02310110 4>;
-		reg-names = "control", "multiplier";
+		reg = <0x02620350 4>, <0x02310110 4>, <0x02310108 4>;
+		reg-names = "control", "multiplier", "post-divider";
 		fixed-postdiv = <2>;
 	};
 

drivers/clk/keystone/pll.c

@@ -37,7 +37,8 @@
  *	Main PLL or any other PLLs in the device such as ARM PLL, DDR PLL
  *	or PA PLL available on keystone2. These PLLs are controlled by
  *	this register. Main PLL is controlled by a PLL controller.
- * @pllm: PLL register map address
+ * @pllm: PLL register map address for multiplier bits
+ * @pllod: PLL register map address for post divider bits
  * @pll_ctl0: PLL controller map address
  * @pllm_lower_mask: multiplier lower mask
  * @pllm_upper_mask: multiplier upper mask
@@ -53,6 +54,7 @@ struct clk_pll_data {
 	u32 phy_pllm;
 	u32 phy_pll_ctl0;
 	void __iomem *pllm;
+	void __iomem *pllod;
 	void __iomem *pll_ctl0;
 	u32 pllm_lower_mask;
 	u32 pllm_upper_mask;
@@ -102,7 +104,11 @@ static unsigned long clk_pllclk_recalc(struct clk_hw *hw,
 		/* read post divider from od bits*/
 		postdiv = ((val & pll_data->clkod_mask) >>
 				 pll_data->clkod_shift) + 1;
-	else
+	else if (pll_data->pllod) {
+		postdiv = readl(pll_data->pllod);
+		postdiv = ((postdiv & pll_data->clkod_mask) >>
+				pll_data->clkod_shift) + 1;
+	} else
 		postdiv = pll_data->postdiv;
 
 	rate /= (prediv + 1);
@@ -172,12 +178,21 @@ static void __init _of_pll_clk_init(struct device_node *node, bool pllctrl)
 		/* assume the PLL has output divider register bits */
 		pll_data->clkod_mask = CLKOD_MASK;
 		pll_data->clkod_shift = CLKOD_SHIFT;
+
+		/*
+		 * Check if there is an post-divider register. If not
+		 * assume od bits are part of control register.
+		 */
+		i = of_property_match_string(node, "reg-names",
+					     "post-divider");
+		pll_data->pllod = of_iomap(node, i);
 	}
 
 	i = of_property_match_string(node, "reg-names", "control");
 	pll_data->pll_ctl0 = of_iomap(node, i);
 	if (!pll_data->pll_ctl0) {
 		pr_err("%s: ioremap failed\n", __func__);
+		iounmap(pll_data->pllod);
 		goto out;
 	}
 
@@ -193,6 +208,7 @@ static void __init _of_pll_clk_init(struct device_node *node, bool pllctrl)
 		pll_data->pllm = of_iomap(node, i);
 		if (!pll_data->pllm) {
 			iounmap(pll_data->pll_ctl0);
+			iounmap(pll_data->pllod);
 			goto out;
 		}
 	}