drivers/clk/socfpga/clk-gate-a10.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2015 Altera Corporation. All rights reserved
 */
#include <linux/slab.h>
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/of.h>
#include <linux/regmap.h>

#include "clk.h"

#define streq(a, b) (strcmp((a), (b)) == 0)

#define to_socfpga_gate_clk(p) container_of(p, struct socfpga_gate_clk, hw.hw)

/* SDMMC Group for System Manager defines */
#define SYSMGR_SDMMCGRP_CTRL_OFFSET	0x28

static unsigned long socfpga_gate_clk_recalc_rate(struct clk_hw *hwclk,
	unsigned long parent_rate)
{
	struct socfpga_gate_clk *socfpgaclk = to_socfpga_gate_clk(hwclk);
	u32 div = 1, 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);
		div = (1 << val);
	}

	return parent_rate / div;
}

static struct clk_ops gateclk_ops = {
	.recalc_rate = socfpga_gate_clk_recalc_rate,
};

static void __init __socfpga_gate_init(struct device_node *node,
				       const struct clk_ops *ops)
{
	u32 clk_gate[2];
	u32 div_reg[3];
	u32 fixed_div;
	struct clk_hw *hw_clk;
	struct socfpga_gate_clk *socfpga_clk;
	const char *clk_name = node->name;
	const char *parent_name[SOCFPGA_MAX_PARENTS];
	struct clk_init_data init;
	int rc;

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

	rc = of_property_read_u32_array(node, "clk-gate", clk_gate, 2);
	if (rc)
		clk_gate[0] = 0;

	if (clk_gate[0]) {
		socfpga_clk->hw.reg = clk_mgr_a10_base_addr + clk_gate[0];
		socfpga_clk->hw.bit_idx = clk_gate[1];

		gateclk_ops.enable = clk_gate_ops.enable;
		gateclk_ops.disable = clk_gate_ops.disable;
	}

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

	rc = of_property_read_u32_array(node, "div-reg", div_reg, 3);
	if (!rc) {
		socfpga_clk->div_reg = clk_mgr_a10_base_addr + div_reg[0];
		socfpga_clk->shift = div_reg[1];
		socfpga_clk->width = div_reg[2];
	} else {
		socfpga_clk->div_reg = NULL;
	}

	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;
	socfpga_clk->hw.hw.init = &init;
	hw_clk = &socfpga_clk->hw.hw;

	rc = clk_hw_register(NULL, hw_clk);
	if (rc) {
		pr_err("Could not register clock:%s\n", clk_name);
		goto err_clk_hw_register;
	}

	rc = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw_clk);
	if (rc) {
		pr_err("Could not register clock provider for node:%s\n",
		       clk_name);
		goto err_of_clk_add_hw_provider;
	}

	return;

err_of_clk_add_hw_provider:
	clk_hw_unregister(hw_clk);
err_clk_hw_register:
	kfree(socfpga_clk);
}

void __init socfpga_a10_gate_init(struct device_node *node)
{
	__socfpga_gate_init(node, &gateclk_ops);
}