arch/sh/kernel/cpu/sh4a/clock-sh7724.c

Source file repositories/reference/linux-study-clean/arch/sh/kernel/cpu/sh4a/clock-sh7724.c

File Facts

System
Linux kernel
Corpus path
arch/sh/kernel/cpu/sh4a/clock-sh7724.c
Extension
.c
Size
12573 bytes
Lines
368
Domain
Architecture Layer
Bucket
arch/sh
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/*
 * arch/sh/kernel/cpu/sh4a/clock-sh7724.c
 *
 * SH7724 clock framework support
 *
 * Copyright (C) 2009 Magnus Damm
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/sh_clk.h>
#include <asm/clock.h>
#include <cpu/sh7724.h>

/* SH7724 registers */
#define FRQCRA		0xa4150000
#define FRQCRB		0xa4150004
#define VCLKCR		0xa4150048
#define FCLKACR		0xa4150008
#define FCLKBCR		0xa415000c
#define IRDACLKCR	0xa4150018
#define PLLCR		0xa4150024
#define MSTPCR0		0xa4150030
#define MSTPCR1		0xa4150034
#define MSTPCR2		0xa4150038
#define SPUCLKCR	0xa415003c
#define FLLFRQ		0xa4150050
#define LSTATS		0xa4150060

/* Fixed 32 KHz root clock for RTC and Power Management purposes */
static struct clk r_clk = {
	.rate           = 32768,
};

/*
 * Default rate for the root input clock, reset this with clk_set_rate()
 * from the platform code.
 */
static struct clk extal_clk = {
	.rate		= 33333333,
};

/* The fll multiplies the 32khz r_clk, may be used instead of extal */
static unsigned long fll_recalc(struct clk *clk)
{
	unsigned long mult = 0;
	unsigned long div = 1;

	if (__raw_readl(PLLCR) & 0x1000)
		mult = __raw_readl(FLLFRQ) & 0x3ff;

	if (__raw_readl(FLLFRQ) & 0x4000)
		div = 2;

	return (clk->parent->rate * mult) / div;
}

static struct sh_clk_ops fll_clk_ops = {
	.recalc		= fll_recalc,
};

static struct clk fll_clk = {
	.ops		= &fll_clk_ops,
	.parent		= &r_clk,
	.flags		= CLK_ENABLE_ON_INIT,
};

static unsigned long pll_recalc(struct clk *clk)
{
	unsigned long mult = 1;

	if (__raw_readl(PLLCR) & 0x4000)
		mult = (((__raw_readl(FRQCRA) >> 24) & 0x3f) + 1) * 2;

	return clk->parent->rate * mult;
}

static struct sh_clk_ops pll_clk_ops = {
	.recalc		= pll_recalc,
};

static struct clk pll_clk = {
	.ops		= &pll_clk_ops,
	.flags		= CLK_ENABLE_ON_INIT,
};

/* A fixed divide-by-3 block use by the div6 clocks */

Annotation

Implementation Notes