clk: samsung: add common clock framework helper functions for Samsung platforms

All Samsung platforms include different types of clock including
fixed-rate, mux, divider and gate clock types. There are typically
hundreds of such clocks on each of the Samsung platforms. To enable
Samsung platforms to register these clocks using the common clock
framework, a bunch of utility functions are introduced here which
simplify the clock registration process. The clocks are usually
statically instantiated and registered with common clock framework.

Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Tested-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Tested-by: Tomasz Figa <t.figa@samsung.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

1 files changed, 273 insertions, 0 deletions

diff --git a/drivers/clk/samsung/clk.c b/drivers/clk/samsung/clk.c
new file mode 100644
index 000000000000..91d12f397f5d
--- /dev/null
+++ b/drivers/clk/samsung/clk.c
@@ -0,0 +1,273 @@
+/*
+ * Copyright (c) 2013 Samsung Electronics Co., Ltd.
+ * Copyright (c) 2013 Linaro Ltd.
+ * Author: Thomas Abraham <thomas.ab@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.
+ *
+ * This file includes utility functions to register clocks to common
+ * clock framework for Samsung platforms.
+*/
+
+#include <linux/syscore_ops.h>
+#include "clk.h"
+
+static DEFINE_SPINLOCK(lock);
+static struct clk **clk_table;
+static void __iomem *reg_base;
+#ifdef CONFIG_OF
+static struct clk_onecell_data clk_data;
+#endif
+
+#ifdef CONFIG_PM_SLEEP
+static struct samsung_clk_reg_dump *reg_dump;
+static unsigned long nr_reg_dump;
+
+static int samsung_clk_suspend(void)
+{
+	struct samsung_clk_reg_dump *rd = reg_dump;
+	unsigned long i;
+
+	for (i = 0; i < nr_reg_dump; i++, rd++)
+		rd->value = __raw_readl(reg_base + rd->offset);
+
+	return 0;
+}
+
+static void samsung_clk_resume(void)
+{
+	struct samsung_clk_reg_dump *rd = reg_dump;
+	unsigned long i;
+
+	for (i = 0; i < nr_reg_dump; i++, rd++)
+		__raw_writel(rd->value, reg_base + rd->offset);
+}
+
+static struct syscore_ops samsung_clk_syscore_ops = {
+	.suspend	= samsung_clk_suspend,
+	.resume		= samsung_clk_resume,
+};
+#endif /* CONFIG_PM_SLEEP */
+
+/* setup the essentials required to support clock lookup using ccf */
+void __init samsung_clk_init(struct device_node *np, void __iomem *base,
+		unsigned long nr_clks, unsigned long *rdump,
+		unsigned long nr_rdump)
+{
+	reg_base = base;
+	if (!np)
+		return;
+
+#ifdef CONFIG_OF
+	clk_table = kzalloc(sizeof(struct clk *) * nr_clks, GFP_KERNEL);
+	if (!clk_table)
+		panic("could not allocate clock lookup table\n");
+
+	clk_data.clks = clk_table;
+	clk_data.clk_num = nr_clks;
+	of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
+#endif
+
+#ifdef CONFIG_PM_SLEEP
+	if (rdump && nr_rdump) {
+		unsigned int idx;
+		reg_dump = kzalloc(sizeof(struct samsung_clk_reg_dump)
+					* nr_rdump, GFP_KERNEL);
+		if (!reg_dump) {
+			pr_err("%s: memory alloc for register dump failed\n",
+					__func__);
+			return;
+		}
+
+		for (idx = 0; idx < nr_rdump; idx++)
+			reg_dump[idx].offset = rdump[idx];
+		nr_reg_dump = nr_rdump;
+		register_syscore_ops(&samsung_clk_syscore_ops);
+	}
+#endif
+}
+
+/* add a clock instance to the clock lookup table used for dt based lookup */
+void samsung_clk_add_lookup(struct clk *clk, unsigned int id)
+{
+	if (clk_table && id)
+		clk_table[id] = clk;
+}
+
+/* register a list of fixed clocks */
+void __init samsung_clk_register_fixed_rate(
+		struct samsung_fixed_rate_clock *list, unsigned int nr_clk)
+{
+	struct clk *clk;
+	unsigned int idx, ret;
+
+	for (idx = 0; idx < nr_clk; idx++, list++) {
+		clk = clk_register_fixed_rate(NULL, list->name,
+			list->parent_name, list->flags, list->fixed_rate);
+		if (IS_ERR(clk)) {
+			pr_err("%s: failed to register clock %s\n", __func__,
+				list->name);
+			continue;
+		}
+
+		samsung_clk_add_lookup(clk, list->id);
+
+		/*
+		 * Unconditionally add a clock lookup for the fixed rate clocks.
+		 * There are not many of these on any of Samsung platforms.
+		 */
+		ret = clk_register_clkdev(clk, list->name, NULL);
+		if (ret)
+			pr_err("%s: failed to register clock lookup for %s",
+				__func__, list->name);
+	}
+}
+
+/* register a list of fixed factor clocks */
+void __init samsung_clk_register_fixed_factor(
+		struct samsung_fixed_factor_clock *list, unsigned int nr_clk)
+{
+	struct clk *clk;
+	unsigned int idx;
+
+	for (idx = 0; idx < nr_clk; idx++, list++) {
+		clk = clk_register_fixed_factor(NULL, list->name,
+			list->parent_name, list->flags, list->mult, list->div);
+		if (IS_ERR(clk)) {
+			pr_err("%s: failed to register clock %s\n", __func__,
+				list->name);
+			continue;
+		}
+
+		samsung_clk_add_lookup(clk, list->id);
+	}
+}
+
+/* register a list of mux clocks */
+void __init samsung_clk_register_mux(struct samsung_mux_clock *list,
+					unsigned int nr_clk)
+{
+	struct clk *clk;
+	unsigned int idx, ret;
+
+	for (idx = 0; idx < nr_clk; idx++, list++) {
+		clk = clk_register_mux(NULL, list->name, list->parent_names,
+			list->num_parents, list->flags, reg_base + list->offset,
+			list->shift, list->width, list->mux_flags, &lock);
+		if (IS_ERR(clk)) {
+			pr_err("%s: failed to register clock %s\n", __func__,
+				list->name);
+			continue;
+		}
+
+		samsung_clk_add_lookup(clk, list->id);
+
+		/* register a clock lookup only if a clock alias is specified */
+		if (list->alias) {
+			ret = clk_register_clkdev(clk, list->alias,
+						list->dev_name);
+			if (ret)
+				pr_err("%s: failed to register lookup %s\n",
+						__func__, list->alias);
+		}
+	}
+}
+
+/* register a list of div clocks */
+void __init samsung_clk_register_div(struct samsung_div_clock *list,
+					unsigned int nr_clk)
+{
+	struct clk *clk;
+	unsigned int idx, ret;
+
+	for (idx = 0; idx < nr_clk; idx++, list++) {
+		clk = clk_register_divider(NULL, list->name, list->parent_name,
+			list->flags, reg_base + list->offset, list->shift,
+			list->width, list->div_flags, &lock);
+		if (IS_ERR(clk)) {
+			pr_err("%s: failed to register clock %s\n", __func__,
+				list->name);
+			continue;
+		}
+
+		samsung_clk_add_lookup(clk, list->id);
+
+		/* register a clock lookup only if a clock alias is specified */
+		if (list->alias) {
+			ret = clk_register_clkdev(clk, list->alias,
+						list->dev_name);
+			if (ret)
+				pr_err("%s: failed to register lookup %s\n",
+						__func__, list->alias);
+		}
+	}
+}
+
+/* register a list of gate clocks */
+void __init samsung_clk_register_gate(struct samsung_gate_clock *list,
+						unsigned int nr_clk)
+{
+	struct clk *clk;
+	unsigned int idx, ret;
+
+	for (idx = 0; idx < nr_clk; idx++, list++) {
+		clk = clk_register_gate(NULL, list->name, list->parent_name,
+				list->flags, reg_base + list->offset,
+				list->bit_idx, list->gate_flags, &lock);
+		if (IS_ERR(clk)) {
+			pr_err("%s: failed to register clock %s\n", __func__,
+				list->name);
+			continue;
+		}
+
+		/* register a clock lookup only if a clock alias is specified */
+		if (list->alias) {
+			ret = clk_register_clkdev(clk, list->alias,
+							list->dev_name);
+			if (ret)
+				pr_err("%s: failed to register lookup %s\n",
+					__func__, list->alias);
+		}
+
+		samsung_clk_add_lookup(clk, list->id);
+	}
+}
+
+/*
+ * obtain the clock speed of all external fixed clock sources from device
+ * tree and register it
+ */
+void __init samsung_clk_of_register_fixed_ext(
+			struct samsung_fixed_rate_clock *fixed_rate_clk,
+			unsigned int nr_fixed_rate_clk,
+			struct of_device_id *clk_matches)
+{
+	const struct of_device_id *match;
+	struct device_node *np;
+	u32 freq;
+
+	for_each_matching_node_and_match(np, clk_matches, &match) {
+		if (of_property_read_u32(np, "clock-frequency", &freq))
+			continue;
+		fixed_rate_clk[(u32)match->data].fixed_rate = freq;
+	}
+	samsung_clk_register_fixed_rate(fixed_rate_clk, nr_fixed_rate_clk);
+}
+
+/* utility function to get the rate of a specified clock */
+unsigned long _get_rate(const char *clk_name)
+{
+	struct clk *clk;
+	unsigned long rate;
+
+	clk = clk_get(NULL, clk_name);
+	if (IS_ERR(clk)) {
+		pr_err("%s: could not find clock %s\n", __func__, clk_name);
+		return 0;
+	}
+	rate = clk_get_rate(clk);
+	clk_put(clk);
+	return rate;
+}