CLK: Add Loongson1C clock support

This patch adds clock support to Loongson1C SoC.

Signed-off-by: Yang Ling <gnaygnil@gmail.com>
Acked-by: Keguang Zhang <keguang.zhang@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/loongson1/Makefile

 obj-y				+= clk.o
 obj-$(CONFIG_LOONGSON1_LS1B)	+= clk-loongson1b.o
+obj-$(CONFIG_LOONGSON1_LS1C)	+= clk-loongson1c.o

drivers/clk/loongson1/clk-loongson1c.c

+/*
+ * Copyright (c) 2016 Yang Ling <gnaygnil@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 <loongson1.h>
+#include "clk.h"
+
+#define OSC		(24 * 1000000)
+#define DIV_APB		1
+
+static DEFINE_SPINLOCK(_lock);
+
+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 = ((pll >> 8) & 0xff) + ((pll >> 16) & 0xff);
+	rate *= OSC;
+	rate >>= 2;
+
+	return rate;
+}
+
+static const struct clk_ops ls1x_pll_clk_ops = {
+	.recalc_rate = ls1x_pll_recalc_rate,
+};
+
+static const struct clk_div_table ahb_div_table[] = {
+	[0] = { .val = 0, .div = 2 },
+	[1] = { .val = 1, .div = 4 },
+	[2] = { .val = 2, .div = 3 },
+	[3] = { .val = 3, .div = 3 },
+};
+
+void __init ls1x_clk_init(void)
+{
+	struct clk_hw *hw;
+
+	hw = clk_hw_register_fixed_rate(NULL, "osc_clk", NULL, 0, OSC);
+	clk_hw_register_clkdev(hw, "osc_clk", NULL);
+
+	/* clock derived from 24 MHz OSC clk */
+	hw = clk_hw_register_pll(NULL, "pll_clk", "osc_clk",
+				&ls1x_pll_clk_ops, 0);
+	clk_hw_register_clkdev(hw, "pll_clk", NULL);
+
+	hw = clk_hw_register_divider(NULL, "cpu_clk_div", "pll_clk",
+				   CLK_GET_RATE_NOCACHE, LS1X_CLK_PLL_DIV,
+				   DIV_CPU_SHIFT, DIV_CPU_WIDTH,
+				   CLK_DIVIDER_ONE_BASED |
+				   CLK_DIVIDER_ROUND_CLOSEST, &_lock);
+	clk_hw_register_clkdev(hw, "cpu_clk_div", NULL);
+	hw = clk_hw_register_fixed_factor(NULL, "cpu_clk", "cpu_clk_div",
+					0, 1, 1);
+	clk_hw_register_clkdev(hw, "cpu_clk", NULL);
+
+	hw = clk_hw_register_divider(NULL, "dc_clk_div", "pll_clk",
+				   0, LS1X_CLK_PLL_DIV, DIV_DC_SHIFT,
+				   DIV_DC_WIDTH, CLK_DIVIDER_ONE_BASED, &_lock);
+	clk_hw_register_clkdev(hw, "dc_clk_div", NULL);
+	hw = clk_hw_register_fixed_factor(NULL, "dc_clk", "dc_clk_div",
+					0, 1, 1);
+	clk_hw_register_clkdev(hw, "dc_clk", NULL);
+
+	hw = clk_hw_register_divider_table(NULL, "ahb_clk_div", "cpu_clk_div",
+				0, LS1X_CLK_PLL_FREQ, DIV_DDR_SHIFT,
+				DIV_DDR_WIDTH, CLK_DIVIDER_ALLOW_ZERO,
+				ahb_div_table, &_lock);
+	clk_hw_register_clkdev(hw, "ahb_clk_div", NULL);
+	hw = clk_hw_register_fixed_factor(NULL, "ahb_clk", "ahb_clk_div",
+					0, 1, 1);
+	clk_hw_register_clkdev(hw, "ahb_clk", NULL);
+	clk_hw_register_clkdev(hw, "ls1x-dma", NULL);
+	clk_hw_register_clkdev(hw, "stmmaceth", NULL);
+
+	/* clock derived from AHB clk */
+	hw = clk_hw_register_fixed_factor(NULL, "apb_clk", "ahb_clk", 0, 1,
+					DIV_APB);
+	clk_hw_register_clkdev(hw, "apb_clk", NULL);
+	clk_hw_register_clkdev(hw, "ls1x-ac97", NULL);
+	clk_hw_register_clkdev(hw, "ls1x-i2c", NULL);
+	clk_hw_register_clkdev(hw, "ls1x-nand", NULL);
+	clk_hw_register_clkdev(hw, "ls1x-pwmtimer", NULL);
+	clk_hw_register_clkdev(hw, "ls1x-spi", NULL);
+	clk_hw_register_clkdev(hw, "ls1x-wdt", NULL);
+	clk_hw_register_clkdev(hw, "serial8250", NULL);
+}