[PATCH v2 01/16] clk: tz1090: add clock provider common code

[James Hogan <james.hogan@imgtec.com>]

Add some common code for the TZ1090 SoC to allocate and register onecell
based clock providers. These have some memory mapped registers and are
instantiated from DT.

Also provided is a tz1090_clk_xlate() function to help handle external
clocks from other clock providers by processing the internal clock
names.

Parent clocks from other providers can be specified as "@label" where
label is the name of an input clock provided by the clock-names DT
property. tz1090_clk_xlate() translates these strings by finding the
actual name of the parent clock. It first uses
of_property_match_string() to find the index of the matching parent
clock, and then of_clk_get_parent_name() to get its name. Since
of_clk_get_parent_name() uses the parent clock node's clock-output-names
property, this should be specified for any complex input clocks which
use this mechanism.

Clock strings which don't start with '@' are used directly as the parent
clock name. This is intended for other clocks within the clock provider.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: linux-metag@vger.kernel.org
---
New patch in v2
---
 drivers/clk/Makefile        |  1 +
 drivers/clk/tz1090/Makefile |  2 +
 drivers/clk/tz1090/clk.c    | 89 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/clk/tz1090/clk.h    | 37 +++++++++++++++++++
 4 files changed, 129 insertions(+)
 create mode 100644 drivers/clk/tz1090/Makefile
 create mode 100644 drivers/clk/tz1090/clk.c
 create mode 100644 drivers/clk/tz1090/clk.h

diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index d5fba5b..ca486ed 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -63,6 +63,7 @@ obj-$(CONFIG_PLAT_SPEAR)		+= spear/
 obj-$(CONFIG_ARCH_STI)			+= st/
 obj-$(CONFIG_ARCH_SUNXI)		+= sunxi/
 obj-$(CONFIG_ARCH_TEGRA)		+= tegra/
+obj-$(CONFIG_SOC_TZ1090)		+= tz1090/
 obj-$(CONFIG_ARCH_OMAP2PLUS)		+= ti/
 obj-$(CONFIG_ARCH_U8500)		+= ux500/
 obj-$(CONFIG_COMMON_CLK_VERSATILE)	+= versatile/
diff --git a/drivers/clk/tz1090/Makefile b/drivers/clk/tz1090/Makefile
new file mode 100644
index 0000000..a2ace14
--- /dev/null
+++ b/drivers/clk/tz1090/Makefile
@@ -0,0 +1,2 @@
+# Makefile for TZ1090-specific clocks
+obj-y		+= clk.o
diff --git a/drivers/clk/tz1090/clk.c b/drivers/clk/tz1090/clk.c
new file mode 100644
index 0000000..5f4e8f28
--- /dev/null
+++ b/drivers/clk/tz1090/clk.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2014 Google, Inc.
+ * Copyright (C) 2014 Imagination Technologies Ltd.
+ *
+ * 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.
+ *
+ * TZ1090 Clocks
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+
+#include "clk.h"
+
+struct tz1090_clk_provider *tz1090_clk_alloc_provider(struct device_node *node,
+						      unsigned int num_clks)
+{
+	struct tz1090_clk_provider *p;
+
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	if (!p)
+		return p;
+
+	p->clk_data.clks = kcalloc(num_clks, sizeof(struct clk *), GFP_KERNEL);
+	if (!p->clk_data.clks)
+		goto free_provider;
+	p->clk_data.clk_num = num_clks;
+	p->node = node;
+	p->base = of_iomap(node, 0);
+	if (!p->base) {
+		pr_err("%s: Failed to map clock provider registers\n",
+		       node->full_name);
+		goto free_clks;
+	}
+
+	return p;
+
+free_clks:
+	kfree(p->clk_data.clks);
+free_provider:
+	kfree(p);
+	return NULL;
+}
+
+const char *tz1090_clk_xlate(struct tz1090_clk_provider *p,
+			     const char *clk_name)
+{
+	/*
+	 * If clock name begins with @, the rest refers to an external clock.
+	 *
+	 * Look for the index of the parent clock with a matching label in
+	 * clock-names. If found, find the name of the specified parent clock.
+	 *
+	 * If not found, we leave it unchanged. The @ at the beginning should
+	 * ensure it doesn't accidentally match a real clock.
+	 */
+	if (*clk_name == '@') {
+		const char *clk_label = clk_name + 1;
+		int idx = of_property_match_string(p->node, "clock-names",
+						   clk_label);
+		if (idx >= 0) {
+			clk_name = of_clk_get_parent_name(p->node, idx);
+			pr_debug("%s: Parent clock '%s' found as '%s'\n",
+				 p->node->full_name, clk_label, clk_name);
+		} else {
+			pr_err("%s: No parent clock '%s' found\n",
+			       p->node->full_name, clk_label);
+		}
+	}
+
+	return clk_name;
+}
+
+void tz1090_clk_register_provider(struct tz1090_clk_provider *p)
+{
+	unsigned int i;
+
+	for (i = 0; i < p->clk_data.clk_num; i++)
+		if (IS_ERR(p->clk_data.clks[i]))
+			pr_warn("%s: Failed to register clock %d: %ld\n",
+				p->node->full_name, i,
+				PTR_ERR(p->clk_data.clks[i]));
+
+	of_clk_add_provider(p->node, of_clk_src_onecell_get, &p->clk_data);
+}
diff --git a/drivers/clk/tz1090/clk.h b/drivers/clk/tz1090/clk.h
new file mode 100644
index 0000000..c20e7b4
--- /dev/null
+++ b/drivers/clk/tz1090/clk.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2014 Imagination Technologies Ltd.
+ *
+ * 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.
+ *
+ * TZ1090 Clocks
+ */
+
+#ifndef CLK_TZ1090_CLK_H
+#define CLK_TZ1090_CLK_H
+
+#include <linux/clk-provider.h>
+#include <linux/init.h>
+
+/* Generic TZ1090 clock provider */
+
+/**
+ * struct tz1090_clk_provider - Clock provider data.
+ * @node:	Device tree node for the clock provider.
+ * @base:	IO remapped base address.
+ * @clk_data:	Standard onecell clock data including list of clocks.
+ */
+struct tz1090_clk_provider {
+	struct device_node		*node;
+	void __iomem			*base;
+	struct clk_onecell_data		clk_data;
+};
+
+struct tz1090_clk_provider *tz1090_clk_alloc_provider(struct device_node *node,
+						      unsigned int num_clks);
+const char *tz1090_clk_xlate(struct tz1090_clk_provider *p,
+			     const char *clk_name);
+void tz1090_clk_register_provider(struct tz1090_clk_provider *p);
+
+#endif
-- 
2.0.4