1 files changed, 188 insertions, 0 deletions

diff --git a/kernel/drivers/clk/versatile/clk-sp810.c b/kernel/drivers/clk/versatile/clk-sp810.c
new file mode 100644
index 000000000..c6e86a9a2
--- /dev/null
+++ b/kernel/drivers/clk/versatile/clk-sp810.c
@@ -0,0 +1,188 @@
+/*
+ * 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 program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2013 ARM Limited
+ */
+
+#include <linux/amba/sp810.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#define to_clk_sp810_timerclken(_hw) \
+		container_of(_hw, struct clk_sp810_timerclken, hw)
+
+struct clk_sp810;
+
+struct clk_sp810_timerclken {
+	struct clk_hw hw;
+	struct clk *clk;
+	struct clk_sp810 *sp810;
+	int channel;
+};
+
+struct clk_sp810 {
+	struct device_node *node;
+	int refclk_index, timclk_index;
+	void __iomem *base;
+	spinlock_t lock;
+	struct clk_sp810_timerclken timerclken[4];
+	struct clk *refclk;
+	struct clk *timclk;
+};
+
+static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw)
+{
+	struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
+	u32 val = readl(timerclken->sp810->base + SCCTRL);
+
+	return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel)));
+}
+
+static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
+	struct clk_sp810 *sp810 = timerclken->sp810;
+	u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel);
+	unsigned long flags = 0;
+
+	if (WARN_ON(index > 1))
+		return -EINVAL;
+
+	spin_lock_irqsave(&sp810->lock, flags);
+
+	val = readl(sp810->base + SCCTRL);
+	val &= ~(1 << shift);
+	val |= index << shift;
+	writel(val, sp810->base + SCCTRL);
+
+	spin_unlock_irqrestore(&sp810->lock, flags);
+
+	return 0;
+}
+
+/*
+ * FIXME - setting the parent every time .prepare is invoked is inefficient.
+ * This is better handled by a dedicated clock tree configuration mechanism at
+ * init-time.  Revisit this later when such a mechanism exists
+ */
+static int clk_sp810_timerclken_prepare(struct clk_hw *hw)
+{
+	struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
+	struct clk_sp810 *sp810 = timerclken->sp810;
+	struct clk *old_parent = __clk_get_parent(hw->clk);
+	struct clk *new_parent;
+
+	if (!sp810->refclk)
+		sp810->refclk = of_clk_get(sp810->node, sp810->refclk_index);
+
+	if (!sp810->timclk)
+		sp810->timclk = of_clk_get(sp810->node, sp810->timclk_index);
+
+	if (WARN_ON(IS_ERR(sp810->refclk) || IS_ERR(sp810->timclk)))
+		return -ENOENT;
+
+	/* Select fastest parent */
+	if (clk_get_rate(sp810->refclk) > clk_get_rate(sp810->timclk))
+		new_parent = sp810->refclk;
+	else
+		new_parent = sp810->timclk;
+
+	/* Switch the parent if necessary */
+	if (old_parent != new_parent) {
+		clk_prepare(new_parent);
+		clk_set_parent(hw->clk, new_parent);
+		clk_unprepare(old_parent);
+	}
+
+	return 0;
+}
+
+static void clk_sp810_timerclken_unprepare(struct clk_hw *hw)
+{
+	struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
+	struct clk_sp810 *sp810 = timerclken->sp810;
+
+	clk_put(sp810->timclk);
+	clk_put(sp810->refclk);
+}
+
+static const struct clk_ops clk_sp810_timerclken_ops = {
+	.prepare = clk_sp810_timerclken_prepare,
+	.unprepare = clk_sp810_timerclken_unprepare,
+	.get_parent = clk_sp810_timerclken_get_parent,
+	.set_parent = clk_sp810_timerclken_set_parent,
+};
+
+static struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec,
+		void *data)
+{
+	struct clk_sp810 *sp810 = data;
+
+	if (WARN_ON(clkspec->args_count != 1 || clkspec->args[0] >
+			ARRAY_SIZE(sp810->timerclken)))
+		return NULL;
+
+	return sp810->timerclken[clkspec->args[0]].clk;
+}
+
+void __init clk_sp810_of_setup(struct device_node *node)
+{
+	struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL);
+	const char *parent_names[2];
+	char name[12];
+	struct clk_init_data init;
+	int i;
+
+	if (!sp810) {
+		pr_err("Failed to allocate memory for SP810!\n");
+		return;
+	}
+
+	sp810->refclk_index = of_property_match_string(node, "clock-names",
+			"refclk");
+	parent_names[0] = of_clk_get_parent_name(node, sp810->refclk_index);
+
+	sp810->timclk_index = of_property_match_string(node, "clock-names",
+			"timclk");
+	parent_names[1] = of_clk_get_parent_name(node, sp810->timclk_index);
+
+	if (parent_names[0] <= 0 || parent_names[1] <= 0) {
+		pr_warn("Failed to obtain parent clocks for SP810!\n");
+		return;
+	}
+
+	sp810->node = node;
+	sp810->base = of_iomap(node, 0);
+	spin_lock_init(&sp810->lock);
+
+	init.name = name;
+	init.ops = &clk_sp810_timerclken_ops;
+	init.flags = CLK_IS_BASIC;
+	init.parent_names = parent_names;
+	init.num_parents = ARRAY_SIZE(parent_names);
+
+	for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
+		snprintf(name, ARRAY_SIZE(name), "timerclken%d", i);
+
+		sp810->timerclken[i].sp810 = sp810;
+		sp810->timerclken[i].channel = i;
+		sp810->timerclken[i].hw.init = &init;
+
+		sp810->timerclken[i].clk = clk_register(NULL,
+				&sp810->timerclken[i].hw);
+		WARN_ON(IS_ERR(sp810->timerclken[i].clk));
+	}
+
+	of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
+}
+CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);