clk: samsung: register audio subsystem clocks using common clock framework

Audio subsystem is introduced in s5pv210 and exynos platforms.
This has seperate clock controller which can control i2s0 and
pcm0 clocks. This patch registers the audio subsystem clocks
with the common clock framework on Exynos family.

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

Documentation/devicetree/bindings/clock/clk-exynos-audss.txt

@@ -0,0 +1,64 @@
+* Samsung Audio Subsystem Clock Controller
+
+The Samsung Audio Subsystem clock controller generates and supplies clocks
+to Audio Subsystem block available in the S5PV210 and Exynos SoCs. The clock
+binding described here is applicable to all SoC's in Exynos family.
+
+Required Properties:
+
+- compatible: should be one of the following:
+  - "samsung,exynos4210-audss-clock" - controller compatible with all Exynos4 SoCs.
+  - "samsung,exynos5250-audss-clock" - controller compatible with all Exynos5 SoCs.
+
+- reg: physical base address and length of the controller's register set.
+
+- #clock-cells: should be 1.
+
+The following is the list of clocks generated by the controller. Each clock is
+assigned an identifier and client nodes use this identifier to specify the
+clock which they consume. Some of the clocks are available only on a particular
+Exynos4 SoC and this is specified where applicable.
+
+Provided clocks:
+
+Clock           ID      SoC (if specific)
+-----------------------------------------------
+
+mout_audss      0
+mout_i2s        1
+dout_srp        2
+dout_aud_bus    3
+dout_i2s        4
+srp_clk         5
+i2s_bus         6
+sclk_i2s        7
+pcm_bus         8
+sclk_pcm        9
+
+Example 1: An example of a clock controller node is listed below.
+
+clock_audss: audss-clock-controller@3810000 {
+	compatible = "samsung,exynos5250-audss-clock";
+	reg = <0x03810000 0x0C>;
+	#clock-cells = <1>;
+};
+
+Example 2: I2S controller node that consumes the clock generated by the clock
+           controller. Refer to the standard clock bindings for information
+           about 'clocks' and 'clock-names' property.
+
+i2s0: i2s@03830000 {
+	compatible = "samsung,i2s-v5";
+	reg = <0x03830000 0x100>;
+	dmas = <&pdma0 10
+		&pdma0 9
+		&pdma0 8>;
+	dma-names = "tx", "rx", "tx-sec";
+	clocks = <&clock_audss EXYNOS_I2S_BUS>,
+		<&clock_audss EXYNOS_I2S_BUS>,
+		<&clock_audss EXYNOS_SCLK_I2S>,
+		<&clock_audss EXYNOS_MOUT_AUDSS>,
+		<&clock_audss EXYNOS_MOUT_I2S>;
+	clock-names = "iis", "i2s_opclk0", "i2s_opclk1",
+	"mout_audss", "mout_i2s";
+};

drivers/clk/samsung/Makefile

@@ -6,3 +6,4 @@ obj-$(CONFIG_COMMON_CLK)	+= clk.o clk-pll.o
 obj-$(CONFIG_ARCH_EXYNOS4)	+= clk-exynos4.o
 obj-$(CONFIG_SOC_EXYNOS5250)	+= clk-exynos5250.o
 obj-$(CONFIG_SOC_EXYNOS5440)	+= clk-exynos5440.o
+obj-$(CONFIG_ARCH_EXYNOS)	+= clk-exynos-audss.o

drivers/clk/samsung/clk-exynos-audss.c

@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) 2013 Samsung Electronics Co., Ltd.
+ * Author: Padmavathi Venna <padma.v@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Common Clock Framework support for Audio Subsystem Clock Controller.
+*/
+
+#include <linux/clkdev.h>
+#include <linux/io.h>
+#include <linux/clk-provider.h>
+#include <linux/of_address.h>
+#include <linux/syscore_ops.h>
+
+#include <dt-bindings/clk/exynos-audss-clk.h>
+
+static DEFINE_SPINLOCK(lock);
+static struct clk **clk_table;
+static void __iomem *reg_base;
+static struct clk_onecell_data clk_data;
+
+#define ASS_CLK_SRC 0x0
+#define ASS_CLK_DIV 0x4
+#define ASS_CLK_GATE 0x8
+
+static unsigned long reg_save[][2] = {
+	{ASS_CLK_SRC,  0},
+	{ASS_CLK_DIV,  0},
+	{ASS_CLK_GATE, 0},
+};
+
+/* list of all parent clock list */
+static const char *mout_audss_p[] = { "fin_pll", "fout_epll" };
+static const char *mout_i2s_p[] = { "mout_audss", "cdclk0", "sclk_audio0" };
+
+#ifdef CONFIG_PM_SLEEP
+static int exynos_audss_clk_suspend(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(reg_save); i++)
+		reg_save[i][1] = readl(reg_base + reg_save[i][0]);
+
+	return 0;
+}
+
+static void exynos_audss_clk_resume(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(reg_save); i++)
+		writel(reg_save[i][1], reg_base + reg_save[i][0]);
+}
+
+static struct syscore_ops exynos_audss_clk_syscore_ops = {
+	.suspend	= exynos_audss_clk_suspend,
+	.resume		= exynos_audss_clk_resume,
+};
+#endif /* CONFIG_PM_SLEEP */
+
+/* register exynos_audss clocks */
+void __init exynos_audss_clk_init(struct device_node *np)
+{
+	reg_base = of_iomap(np, 0);
+	if (!reg_base) {
+		pr_err("%s: failed to map audss registers\n", __func__);
+		return;
+	}
+
+	clk_table = kzalloc(sizeof(struct clk *) * EXYNOS_AUDSS_MAX_CLKS,
+				GFP_KERNEL);
+	if (!clk_table) {
+		pr_err("%s: could not allocate clk lookup table\n", __func__);
+		return;
+	}
+
+	clk_data.clks = clk_table;
+	clk_data.clk_num = EXYNOS_AUDSS_MAX_CLKS;
+	of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
+
+	clk_table[EXYNOS_MOUT_AUDSS] = clk_register_mux(NULL, "mout_audss",
+				mout_audss_p, ARRAY_SIZE(mout_audss_p), 0,
+				reg_base + ASS_CLK_SRC, 0, 1, 0, &lock);
+
+	clk_table[EXYNOS_MOUT_I2S] = clk_register_mux(NULL, "mout_i2s",
+				mout_i2s_p, ARRAY_SIZE(mout_i2s_p), 0,
+				reg_base + ASS_CLK_SRC, 2, 2, 0, &lock);
+
+	clk_table[EXYNOS_DOUT_SRP] = clk_register_divider(NULL, "dout_srp",
+				"mout_audss", 0, reg_base + ASS_CLK_DIV, 0, 4,
+				0, &lock);
+
+	clk_table[EXYNOS_DOUT_AUD_BUS] = clk_register_divider(NULL,
+				"dout_aud_bus", "dout_srp", 0,
+				reg_base + ASS_CLK_DIV, 4, 4, 0, &lock);
+
+	clk_table[EXYNOS_DOUT_I2S] = clk_register_divider(NULL, "dout_i2s",
+				"mout_i2s", 0, reg_base + ASS_CLK_DIV, 8, 4, 0,
+				&lock);
+
+	clk_table[EXYNOS_SRP_CLK] = clk_register_gate(NULL, "srp_clk",
+				"dout_srp", CLK_SET_RATE_PARENT,
+				reg_base + ASS_CLK_GATE, 0, 0, &lock);
+
+	clk_table[EXYNOS_I2S_BUS] = clk_register_gate(NULL, "i2s_bus",
+				"dout_aud_bus", CLK_SET_RATE_PARENT,
+				reg_base + ASS_CLK_GATE, 2, 0, &lock);
+
+	clk_table[EXYNOS_SCLK_I2S] = clk_register_gate(NULL, "sclk_i2s",
+				"dout_i2s", CLK_SET_RATE_PARENT,
+				reg_base + ASS_CLK_GATE, 3, 0, &lock);
+
+	clk_table[EXYNOS_PCM_BUS] = clk_register_gate(NULL, "pcm_bus",
+				 "sclk_pcm", CLK_SET_RATE_PARENT,
+				reg_base + ASS_CLK_GATE, 4, 0, &lock);
+
+	clk_table[EXYNOS_SCLK_PCM] = clk_register_gate(NULL, "sclk_pcm",
+				"div_pcm0", CLK_SET_RATE_PARENT,
+				reg_base + ASS_CLK_GATE, 5, 0, &lock);
+
+#ifdef CONFIG_PM_SLEEP
+	register_syscore_ops(&exynos_audss_clk_syscore_ops);
+#endif
+
+	pr_info("Exynos: Audss: clock setup completed\n");
+}
+CLK_OF_DECLARE(exynos4210_audss_clk, "samsung,exynos4210-audss-clock",
+		exynos_audss_clk_init);
+CLK_OF_DECLARE(exynos5250_audss_clk, "samsung,exynos5250-audss-clock",
+		exynos_audss_clk_init);

include/dt-bindings/clk/exynos-audss-clk.h

@@ -0,0 +1,25 @@
+/*
+ * This header provides constants for Samsung audio subsystem
+ * clock controller.
+ *
+ * The constants defined in this header are being used in dts
+ * and exynos audss driver.
+ */
+
+#ifndef _DT_BINDINGS_CLK_EXYNOS_AUDSS_H
+#define _DT_BINDINGS_CLK_EXYNOS_AUDSS_H
+
+#define EXYNOS_MOUT_AUDSS	0
+#define EXYNOS_MOUT_I2S	1
+#define EXYNOS_DOUT_SRP	2
+#define EXYNOS_DOUT_AUD_BUS	3
+#define EXYNOS_DOUT_I2S	4
+#define EXYNOS_SRP_CLK		5
+#define EXYNOS_I2S_BUS		6
+#define EXYNOS_SCLK_I2S	7
+#define EXYNOS_PCM_BUS		8
+#define EXYNOS_SCLK_PCM	9
+
+#define EXYNOS_AUDSS_MAX_CLKS	10
+
+#endif