clk: add Loongson1B clock support

This adds clock support to Loongson1B SoC using the common clock
infrastructure.
Signed-off-by: Kelvin Cheung <keguang.zhang@gmail.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_ARCH_PRIMA2)	+= clk-prima2.o
 ifeq ($(CONFIG_COMMON_CLK), y)
 obj-$(CONFIG_ARCH_MMP)		+= mmp/
 endif
+obj-$(CONFIG_MACH_LOONGSON1)	+= clk-ls1x.o
 
 # Chip specific
 obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o

drivers/clk/clk-ls1x.c

+/*
+ * Copyright (c) 2012 Zhang, Keguang <keguang.zhang@gmail.com>
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+
+#include <loongson1.h>
+
+#define OSC	33
+
+static DEFINE_SPINLOCK(_lock);
+
+static int ls1x_pll_clk_enable(struct clk_hw *hw)
+{
+	return 0;
+}
+
+static void ls1x_pll_clk_disable(struct clk_hw *hw)
+{
+}
+
+static unsigned long ls1x_pll_recalc_rate(struct clk_hw *hw,
+					     unsigned long parent_rate)
+{
+	u32 pll, rate;
+
+	pll = __raw_readl(LS1X_CLK_PLL_FREQ);
+	rate = ((12 + (pll & 0x3f)) * 1000000) +
+		((((pll >> 8) & 0x3ff) * 1000000) >> 10);
+	rate *= OSC;
+	rate >>= 1;
+
+	return rate;
+}
+
+static const struct clk_ops ls1x_pll_clk_ops = {
+	.enable = ls1x_pll_clk_enable,
+	.disable = ls1x_pll_clk_disable,
+	.recalc_rate = ls1x_pll_recalc_rate,
+};
+
+static struct clk * __init clk_register_pll(struct device *dev,
+	 const char *name, const char *parent_name, unsigned long flags)
+{
+	struct clk_hw *hw;
+	struct clk *clk;
+	struct clk_init_data init;
+
+	/* allocate the divider */
+	hw = kzalloc(sizeof(struct clk_hw), GFP_KERNEL);
+	if (!hw) {
+		pr_err("%s: could not allocate clk_hw\n", __func__);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	init.name = name;
+	init.ops = &ls1x_pll_clk_ops;
+	init.flags = flags | CLK_IS_BASIC;
+	init.parent_names = (parent_name ? &parent_name : NULL);
+	init.num_parents = (parent_name ? 1 : 0);
+	hw->init = &init;
+
+	/* register the clock */
+	clk = clk_register(dev, hw);
+
+	if (IS_ERR(clk))
+		kfree(hw);
+
+	return clk;
+}
+
+void __init ls1x_clk_init(void)
+{
+	struct clk *clk;
+
+	clk = clk_register_pll(NULL, "pll_clk", NULL, CLK_IS_ROOT);
+	clk_prepare_enable(clk);
+
+	clk = clk_register_divider(NULL, "cpu_clk", "pll_clk",
+			CLK_SET_RATE_PARENT, LS1X_CLK_PLL_DIV, DIV_CPU_SHIFT,
+			DIV_CPU_WIDTH, CLK_DIVIDER_ONE_BASED, &_lock);
+	clk_prepare_enable(clk);
+	clk_register_clkdev(clk, "cpu", NULL);
+
+	clk = clk_register_divider(NULL, "dc_clk", "pll_clk",
+			CLK_SET_RATE_PARENT, LS1X_CLK_PLL_DIV, DIV_DC_SHIFT,
+			DIV_DC_WIDTH, CLK_DIVIDER_ONE_BASED, &_lock);
+	clk_prepare_enable(clk);
+	clk_register_clkdev(clk, "dc", NULL);
+
+	clk = clk_register_divider(NULL, "ahb_clk", "pll_clk",
+			CLK_SET_RATE_PARENT, LS1X_CLK_PLL_DIV, DIV_DDR_SHIFT,
+			DIV_DDR_WIDTH, CLK_DIVIDER_ONE_BASED, &_lock);
+	clk_prepare_enable(clk);
+	clk_register_clkdev(clk, "ahb", NULL);
+	clk_register_clkdev(clk, "stmmaceth", NULL);
+
+	clk = clk_register_fixed_factor(NULL, "apb_clk", "ahb_clk", 0, 1, 2);
+	clk_prepare_enable(clk);
+	clk_register_clkdev(clk, "apb", NULL);
+	clk_register_clkdev(clk, "serial8250", NULL);
+}