--- /dev/null
+/*
+ * 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);
Code Review / kvmfornfv.git / blobdiff