alistair23-linux/drivers/clk/socfpga/clk-periph.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright 2011-2012 Calxeda, Inc.
 *  Copyright (C) 2012-2013 Altera Corporation <www.altera.com>
 *
 * Based from clk-highbank.c
 */
#include <linux/slab.h>
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/of.h>

#include "clk.h"

#define to_socfpga_periph_clk(p) container_of(p, struct socfpga_periph_clk, hw.hw)

static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
					     unsigned long parent_rate)
{
	struct socfpga_periph_clk *socfpgaclk = to_socfpga_periph_clk(hwclk);
	u32 div, val;

	if (socfpgaclk->fixed_div) {
		div = socfpgaclk->fixed_div;
	} else {
		if (socfpgaclk->div_reg) {
			val = readl(socfpgaclk->div_reg) >> socfpgaclk->shift;
			val &= GENMASK(socfpgaclk->width - 1, 0);
			parent_rate /= (val + 1);
		}
		div = ((readl(socfpgaclk->hw.reg) & 0x1ff) + 1);
	}

	return parent_rate / div;
}

static u8 clk_periclk_get_parent(struct clk_hw *hwclk)
{
	u32 clk_src;

	clk_src = readl(clk_mgr_base_addr + CLKMGR_DBCTRL);
	return clk_src & 0x1;
}

static const struct clk_ops periclk_ops = {
	.recalc_rate = clk_periclk_recalc_rate,
	.get_parent = clk_periclk_get_parent,
};

static __init void __socfpga_periph_init(struct device_node *node,
	const struct clk_ops *ops)
{
	u32 reg;
	struct clk *clk;
	struct socfpga_periph_clk *periph_clk;
	const char *clk_name = node->name;
	const char *parent_name[SOCFPGA_MAX_PARENTS];
	struct clk_init_data init;
	int rc;
	u32 fixed_div;
	u32 div_reg[3];

	of_property_read_u32(node, "reg", &reg);

	periph_clk = kzalloc(sizeof(*periph_clk), GFP_KERNEL);
	if (WARN_ON(!periph_clk))
		return;

	periph_clk->hw.reg = clk_mgr_base_addr + reg;

	rc = of_property_read_u32_array(node, "div-reg", div_reg, 3);
	if (!rc) {
		periph_clk->div_reg = clk_mgr_base_addr + div_reg[0];
		periph_clk->shift = div_reg[1];
		periph_clk->width = div_reg[2];
	} else {
		periph_clk->div_reg = NULL;
	}

	rc = of_property_read_u32(node, "fixed-divider", &fixed_div);
	if (rc)
		periph_clk->fixed_div = 0;
	else
		periph_clk->fixed_div = fixed_div;

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

	init.name = clk_name;
	init.ops = ops;
	init.flags = 0;

	init.num_parents = of_clk_parent_fill(node, parent_name,
					      SOCFPGA_MAX_PARENTS);
	init.parent_names = parent_name;

	periph_clk->hw.hw.init = &init;

	clk = clk_register(NULL, &periph_clk->hw.hw);
	if (WARN_ON(IS_ERR(clk))) {
		kfree(periph_clk);
		return;
	}
	rc = of_clk_add_provider(node, of_clk_src_simple_get, clk);
}

void __init socfpga_periph_init(struct device_node *node)
{
	__socfpga_periph_init(node, &periclk_ops);
}