clk: samsung: Add support for EPLL on exynos5410

This patch adds code instantiating the EPLL, which is used as the
audio subsystem's root clock.
The requirement to specify the external root clock in clocks property
is documented.  Having the consumer 'clocks' property ensures proper
initialization order by explicitly specifying dependencies in DT.
It prevents situations when the SoC's clock controller driver has
initialized, the external oscillator clock is not yet registered
and setting clock frequencies through assigned-clock-rates property
doesn't work properly due to unknown external oscillator frequency.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>

Documentation/devicetree/bindings/clock/exynos5410-clock.txt

@@ -12,24 +12,29 @@ Required Properties:
 
 - #clock-cells: should be 1.
 
+- clocks: should contain an entry specifying the root clock from external
+  oscillator supplied through XXTI or XusbXTI pin.  This clock should be
+  defined using standard clock bindings with "fin_pll" clock-output-name.
+  That clock is being passed internally to the 9 PLLs.
+
 All available clocks are defined as preprocessor macros in
 dt-bindings/clock/exynos5410.h header and can be used in device
 tree sources.
 
-External clock:
-
-There is clock that is generated outside the SoC. It
-is expected that it is defined using standard clock bindings
-with following clock-output-name:
-
- - "fin_pll" - PLL input clock from XXTI
-
 Example 1: An example of a clock controller node is listed below.
 
+	fin_pll: xxti {
+		compatible = "fixed-clock";
+		clock-frequency = <24000000>;
+		clock-output-names = "fin_pll";
+		#clock-cells = <0>;
+	};
+
 	clock: clock-controller@0x10010000 {
 		compatible = "samsung,exynos5410-clock";
 		reg = <0x10010000 0x30000>;
 		#clock-cells = <1>;
+		clocks = <&fin_pll>;
 	};
 
 Example 2: UART controller node that consumes the clock generated by the clock

drivers/clk/samsung/clk-exynos5410.c

@@ -14,6 +14,7 @@
 #include <linux/clk-provider.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/clk.h>
 
 #include "clk.h"
 
@@ -21,6 +22,8 @@
 #define APLL_CON0               0x100
 #define CPLL_LOCK               0x10020
 #define CPLL_CON0               0x10120
+#define EPLL_LOCK               0x10040
+#define EPLL_CON0               0x10130
 #define MPLL_LOCK               0x4000
 #define MPLL_CON0               0x4100
 #define BPLL_LOCK               0x20010
@@ -58,7 +61,7 @@
 
 /* list of PLLs */
 enum exynos5410_plls {
-	apll, cpll, mpll,
+	apll, cpll, epll, mpll,
 	bpll, kpll,
 	nr_plls                 /* number of PLLs */
 };
@@ -67,6 +70,7 @@ enum exynos5410_plls {
 PNAME(apll_p)		= { "fin_pll", "fout_apll", };
 PNAME(bpll_p)		= { "fin_pll", "fout_bpll", };
 PNAME(cpll_p)		= { "fin_pll", "fout_cpll" };
+PNAME(epll_p)		= { "fin_pll", "fout_epll" };
 PNAME(mpll_p)		= { "fin_pll", "fout_mpll", };
 PNAME(kpll_p)		= { "fin_pll", "fout_kpll", };
 
@@ -95,6 +99,8 @@ static const struct samsung_mux_clock exynos5410_mux_clks[] __initconst = {
 	MUX(0, "sclk_bpll", bpll_p, SRC_CDREX, 0, 1),
 	MUX(0, "sclk_bpll_muxed", bpll_user_p, SRC_TOP2, 24, 1),
 
+	MUX(0, "sclk_epll", epll_p, SRC_TOP2, 12, 1),
+
 	MUX(0, "sclk_cpll", cpll_p, SRC_TOP2, 8, 1),
 
 	MUX(0, "sclk_mpll_bpll", mpll_bpll_p, SRC_TOP1, 20, 1),
@@ -219,11 +225,26 @@ static const struct samsung_gate_clock exynos5410_gate_clks[] __initconst = {
 	GATE(CLK_USBD301, "usbd301", "aclk200_fsys", GATE_IP_FSYS, 20, 0, 0),
 };
 
-static const struct samsung_pll_clock exynos5410_plls[nr_plls] __initconst = {
+static const struct samsung_pll_rate_table exynos5410_pll2550x_24mhz_tbl[] __initconst = {
+	PLL_36XX_RATE(400000000U, 200, 3, 2, 0),
+	PLL_36XX_RATE(333000000U, 111, 2, 2, 0),
+	PLL_36XX_RATE(300000000U, 100, 2, 2, 0),
+	PLL_36XX_RATE(266000000U, 266, 3, 3, 0),
+	PLL_36XX_RATE(200000000U, 200, 3, 3, 0),
+	PLL_36XX_RATE(192000000U, 192, 3, 3, 0),
+	PLL_36XX_RATE(166000000U, 166, 3, 3, 0),
+	PLL_36XX_RATE(133000000U, 266, 3, 4, 0),
+	PLL_36XX_RATE(100000000U, 200, 3, 4, 0),
+	PLL_36XX_RATE(66000000U,  176, 2, 5, 0),
+};
+
+static struct samsung_pll_clock exynos5410_plls[nr_plls] __initdata = {
 	[apll] = PLL(pll_35xx, CLK_FOUT_APLL, "fout_apll", "fin_pll", APLL_LOCK,
 		APLL_CON0, NULL),
 	[cpll] = PLL(pll_35xx, CLK_FOUT_CPLL, "fout_cpll", "fin_pll", CPLL_LOCK,
 		CPLL_CON0, NULL),
+	[epll] = PLL(pll_2650x, CLK_FOUT_EPLL, "fout_epll", "fin_pll", EPLL_LOCK,
+		EPLL_CON0, NULL),
 	[mpll] = PLL(pll_35xx, CLK_FOUT_MPLL, "fout_mpll", "fin_pll", MPLL_LOCK,
 		MPLL_CON0, NULL),
 	[bpll] = PLL(pll_35xx, CLK_FOUT_BPLL, "fout_bpll", "fin_pll", BPLL_LOCK,
@@ -247,6 +268,11 @@ static const struct samsung_cmu_info cmu __initconst = {
 /* register exynos5410 clocks */
 static void __init exynos5410_clk_init(struct device_node *np)
 {
+	struct clk *xxti = of_clk_get(np, 0);
+
+	if (!IS_ERR(xxti) && clk_get_rate(xxti) == 24 * MHZ)
+		exynos5410_plls[epll].rate_table = exynos5410_pll2550x_24mhz_tbl;
+
 	samsung_cmu_register_one(np, &cmu);
 
 	pr_debug("Exynos5410: clock setup completed.\n");

drivers/clk/samsung/clk-pll.c

@@ -1017,6 +1017,102 @@ static const struct clk_ops samsung_pll2550xx_clk_min_ops = {
 	.recalc_rate = samsung_pll2550xx_recalc_rate,
 };
 
+/*
+ * PLL2650x Clock Type
+ */
+
+/* Maximum lock time can be 3000 * PDIV cycles */
+#define PLL2650X_LOCK_FACTOR		3000
+
+#define PLL2650X_M_MASK			0x1ff
+#define PLL2650X_P_MASK			0x3f
+#define PLL2650X_S_MASK			0x7
+#define PLL2650X_K_MASK			0xffff
+#define PLL2650X_LOCK_STAT_MASK		0x1
+#define PLL2650X_M_SHIFT		16
+#define PLL2650X_P_SHIFT		8
+#define PLL2650X_S_SHIFT		0
+#define PLL2650X_K_SHIFT		0
+#define PLL2650X_LOCK_STAT_SHIFT	29
+#define PLL2650X_PLL_ENABLE_SHIFT	31
+
+static unsigned long samsung_pll2650x_recalc_rate(struct clk_hw *hw,
+				unsigned long parent_rate)
+{
+	struct samsung_clk_pll *pll = to_clk_pll(hw);
+	u64 fout = parent_rate;
+	u32 mdiv, pdiv, sdiv, pll_con0, pll_con1;
+	s16 kdiv;
+
+	pll_con0 = readl_relaxed(pll->con_reg);
+	mdiv = (pll_con0 >> PLL2650X_M_SHIFT) & PLL2650X_M_MASK;
+	pdiv = (pll_con0 >> PLL2650X_P_SHIFT) & PLL2650X_P_MASK;
+	sdiv = (pll_con0 >> PLL2650X_S_SHIFT) & PLL2650X_S_MASK;
+
+	pll_con1 = readl_relaxed(pll->con_reg + 4);
+	kdiv = (s16)((pll_con1 >> PLL2650X_K_SHIFT) & PLL2650X_K_MASK);
+
+	fout *= (mdiv << 16) + kdiv;
+	do_div(fout, (pdiv << sdiv));
+	fout >>= 16;
+
+	return (unsigned long)fout;
+}
+
+static int samsung_pll2650x_set_rate(struct clk_hw *hw, unsigned long drate,
+					unsigned long prate)
+{
+	struct samsung_clk_pll *pll = to_clk_pll(hw);
+	const struct samsung_pll_rate_table *rate;
+	u32 con0, con1;
+
+	/* Get required rate settings from table */
+	rate = samsung_get_pll_settings(pll, drate);
+	if (!rate) {
+		pr_err("%s: Invalid rate : %lu for pll clk %s\n", __func__,
+			drate, clk_hw_get_name(hw));
+		return -EINVAL;
+	}
+
+	con0 = readl_relaxed(pll->con_reg);
+	con1 = readl_relaxed(pll->con_reg + 4);
+
+	/* Set PLL lock time. */
+	writel_relaxed(rate->pdiv * PLL2650X_LOCK_FACTOR, pll->lock_reg);
+
+	/* Change PLL PMS values */
+	con0 &= ~((PLL2650X_M_MASK << PLL2650X_M_SHIFT) |
+			(PLL2650X_P_MASK << PLL2650X_P_SHIFT) |
+			(PLL2650X_S_MASK << PLL2650X_S_SHIFT));
+	con0 |= (rate->mdiv << PLL2650X_M_SHIFT) |
+			(rate->pdiv << PLL2650X_P_SHIFT) |
+			(rate->sdiv << PLL2650X_S_SHIFT);
+	con0 |= (1 << PLL2650X_PLL_ENABLE_SHIFT);
+	writel_relaxed(con0, pll->con_reg);
+
+	con1 &= ~(PLL2650X_K_MASK << PLL2650X_K_SHIFT);
+	con1 |= ((rate->kdiv & PLL2650X_K_MASK) << PLL2650X_K_SHIFT);
+	writel_relaxed(con1, pll->con_reg + 4);
+
+	do {
+		cpu_relax();
+		con0 = readl_relaxed(pll->con_reg);
+	} while (!(con0 & (PLL2650X_LOCK_STAT_MASK
+			<< PLL2650X_LOCK_STAT_SHIFT)));
+
+	return 0;
+}
+
+static const struct clk_ops samsung_pll2650x_clk_ops = {
+	.recalc_rate = samsung_pll2650x_recalc_rate,
+	.round_rate = samsung_pll_round_rate,
+	.set_rate = samsung_pll2650x_set_rate,
+};
+
+static const struct clk_ops samsung_pll2650x_clk_min_ops = {
+	.recalc_rate = samsung_pll2650x_recalc_rate,
+};
+
 /*
  * PLL2650XX Clock Type
  */
@@ -1227,6 +1323,12 @@ static void __init _samsung_clk_register_pll(struct samsung_clk_provider *ctx,
 		else
 			init.ops = &samsung_pll2550xx_clk_ops;
 		break;
+	case pll_2650x:
+		if (!pll->rate_table)
+			init.ops = &samsung_pll2650x_clk_min_ops;
+		else
+			init.ops = &samsung_pll2650x_clk_ops;
+		break;
 	case pll_2650xx:
 		if (!pll->rate_table)
 			init.ops = &samsung_pll2650xx_clk_min_ops;

drivers/clk/samsung/clk-pll.h

@@ -33,6 +33,7 @@ enum samsung_pll_type {
 	pll_s3c2440_mpll,
 	pll_2550x,
 	pll_2550xx,
+	pll_2650x,
 	pll_2650xx,
 	pll_1450x,
 	pll_1451x,