drivers/clk/aspeed/clk-g5.c

/*
 * Copyright 2016 IBM Corporation
 *
 * 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/clk.h>
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/clkdev.h>

static void __init aspeed_of_clkin_clk_init(struct device_node *node)
{
	struct clk *clk;
	void __iomem *base;
	int reg, rate;
	const char *name = node->name;

	of_property_read_string(node, "clock-output-names", &name);

	base = of_iomap(node, 0);
	if (!base) {
		pr_err("%s: of_iomap failed\n", node->full_name);
		return;
	}
	/* Strap register SCU70 */
	reg = readl(base) & BIT(23);
	iounmap(base);

	if (reg)
		rate = 25 * 1000 * 1000;
	else
		rate = 24 * 1000 * 1000;

	clk = clk_register_fixed_rate(NULL, name, NULL, 0, rate);
	if (IS_ERR(clk)) {
		pr_err("%s: failed to register clock\n", node->full_name);
		return;
	}

	clk_register_clkdev(clk, NULL, name);
	of_clk_add_provider(node, of_clk_src_simple_get, clk);
}
CLK_OF_DECLARE(aspeed_clkin_clock, "aspeed,g5-clkin-clock",
	       aspeed_of_clkin_clk_init);


static void __init aspeed_of_hpll_clk_init(struct device_node *node)
{
	struct clk *clk, *clkin_clk;
	void __iomem *base;
	int reg, rate, clkin;
	const char *name = node->name;
	const char *parent_name;

	of_property_read_string(node, "clock-output-names", &name);
	parent_name = of_clk_get_parent_name(node, 0);

	base = of_iomap(node, 0);
	if (!base) {
		pr_err("%s: of_iomap failed\n", node->full_name);
		return;
	}
	/* H-PLL parameter register SCU24 */
	reg = readl(base);
	iounmap(base);

	clkin_clk = of_clk_get(node, 0);
	if (IS_ERR(clkin_clk)) {
		pr_err("%s: of_clk_get failed\n", node->full_name);
		return;
	}

	clkin = clk_get_rate(clkin_clk);

	if (reg & BIT(21)) {
		rate = 0;
	} else if (reg & BIT(20)) {
		rate = clkin;
	} else {
		int p = (reg >> 13) & 0x3f;
		int m = (reg >> 5) & 0xff;
		int n = reg & 0x1f;

		rate = clkin * ((m + 1) / (n + 1)) / (p + 1);
	}

	clk = clk_register_fixed_rate(NULL, name, parent_name, 0, rate);
	if (IS_ERR(clk)) {
		pr_err("%s: failed to register clock\n", node->full_name);
		return;
	}

	clk_register_clkdev(clk, NULL, name);
	of_clk_add_provider(node, of_clk_src_simple_get, clk);
}
CLK_OF_DECLARE(aspeed_hpll_clock, "aspeed,g5-hpll-clock",
	       aspeed_of_hpll_clk_init);


static void __init aspeed_of_ahb_clk_init(struct device_node *node)
{
	struct clk *clk, *hpll_clk;
	void __iomem *base;
	int reg, rate, hpll;
	const char *name = node->name;
	const char *parent_name;

	of_property_read_string(node, "clock-output-names", &name);
	parent_name = of_clk_get_parent_name(node, 0);

	/* Strap register SCU70 */
	base = of_iomap(node, 0);
	if (!base) {
		pr_err("%s: of_iomap failed\n", node->full_name);
		return;
	}
	reg = (readl(base) >> 9) & 0x03;
	iounmap(base);

	/* A value of zero is undefined */
	WARN_ON(reg == 0);

	hpll_clk = of_clk_get(node, 0);
	if (IS_ERR(hpll_clk)) {
		pr_err("%s: of_clk_get failed\n", node->full_name);
		return;
	}

	hpll = clk_get_rate(hpll_clk);

	rate = hpll / 2 / (reg + 1);

	clk = clk_register_fixed_rate(NULL, name, parent_name, 0, rate);
	if (IS_ERR(clk)) {
		pr_err("%s: failed to register clock\n", node->full_name);
		return;
	}

	clk_register_clkdev(clk, NULL, name);
	of_clk_add_provider(node, of_clk_src_simple_get, clk);
}
CLK_OF_DECLARE(aspeed_ahb_clock, "aspeed,g5-ahb-clock",
	       aspeed_of_ahb_clk_init);


static void __init aspeed_of_apb_clk_init(struct device_node *node)
{
	struct clk *clk, *hpll_clk;
	void __iomem *base;
	int reg, rate;
	const char *name = node->name;
	const char *parent_name;

	of_property_read_string(node, "clock-output-names", &name);
	parent_name = of_clk_get_parent_name(node, 0);

	/* Clock selection register SCU08 */
	base = of_iomap(node, 0);
	if (!base) {
		pr_err("%s: of_iomap failed\n", node->full_name);
		return;
	}
	reg = readl(base) >> 23 & 0x7;
	iounmap(base);

	hpll_clk = of_clk_get(node, 0);
	if (IS_ERR(hpll_clk)) {
		pr_err("%s: of_clk_get failed\n", node->full_name);
		return;
	}

	rate = clk_get_rate(hpll_clk) / (4 * (reg + 1));

	clk = clk_register_fixed_rate(NULL, name, parent_name, 0, rate);
	if (IS_ERR(clk)) {
		pr_err("%s: failed to register clock\n", node->full_name);
		return;
	}

	clk_register_clkdev(clk, NULL, name);
	of_clk_add_provider(node, of_clk_src_simple_get, clk);
}
CLK_OF_DECLARE(aspeed_apb_clock, "aspeed,g5-apb-clock",
	       aspeed_of_apb_clk_init);