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>

1 files changed, 28 insertions, 2 deletions

diff --git a/drivers/clk/samsung/clk-exynos5410.c b/drivers/clk/samsung/clk-exynos5410.c
index eefed92a59aa..fc471a49e8f4 100644
--- a/drivers/clk/samsung/clk-exynos5410.c
+++ b/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");