drivers/clk/renesas/clk-rz.c

Source file repositories/reference/linux-study-clean/drivers/clk/renesas/clk-rz.c

File Facts

System
Linux kernel
Corpus path
drivers/clk/renesas/clk-rz.c
Extension
.c
Size
3018 bytes
Lines
122
Domain
Driver Families
Bucket
drivers/clk
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/*
 * RZ/A1 Core CPG Clocks
 *
 * Copyright (C) 2013 Ideas On Board SPRL
 * Copyright (C) 2014 Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
 */

#include <linux/clk-provider.h>
#include <linux/clk/renesas.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/slab.h>

#define CPG_FRQCR	0x10
#define CPG_FRQCR2	0x14

#define PPR0		0xFCFE3200
#define PIBC0		0xFCFE7000

#define MD_CLK(x)	((x >> 2) & 1)	/* P0_2 */

/* -----------------------------------------------------------------------------
 * Initialization
 */

static u16 __init rz_cpg_read_mode_pins(void)
{
	void __iomem *ppr0, *pibc0;
	u16 modes;

	ppr0 = ioremap(PPR0, 2);
	pibc0 = ioremap(PIBC0, 2);
	BUG_ON(!ppr0 || !pibc0);
	iowrite16(4, pibc0);	/* enable input buffer */
	modes = ioread16(ppr0);
	iounmap(ppr0);
	iounmap(pibc0);

	return modes;
}

static struct clk * __init
rz_cpg_register_clock(struct device_node *np, void __iomem *base,
		      const char *name)
{
	u32 val;
	unsigned mult;
	static const unsigned frqcr_tab[4] = { 3, 2, 0, 1 };

	if (strcmp(name, "pll") == 0) {
		unsigned int cpg_mode = MD_CLK(rz_cpg_read_mode_pins());
		const char *parent_name = of_clk_get_parent_name(np, cpg_mode);

		mult = cpg_mode ? (32 / 4) : 30;

		return clk_register_fixed_factor(NULL, name, parent_name, 0, mult, 1);
	}

	/* If mapping regs failed, skip non-pll clocks. System will boot anyhow */
	if (!base)
		return ERR_PTR(-ENXIO);

	/* FIXME:"i" and "g" are variable clocks with non-integer dividers (e.g. 2/3)
	 * and the constraint that always g <= i. To get the rz platform started,
	 * let them run at fixed current speed and implement the details later.
	 */
	if (strcmp(name, "i") == 0)
		val = (readl(base + CPG_FRQCR) >> 8) & 3;
	else if (strcmp(name, "g") == 0)
		val = readl(base + CPG_FRQCR2) & 3;
	else
		return ERR_PTR(-EINVAL);

	mult = frqcr_tab[val];
	return clk_register_fixed_factor(NULL, name, "pll", 0, mult, 3);
}

static void __init rz_cpg_clocks_init(struct device_node *np)
{
	struct clk_onecell_data *data;
	struct clk **clks;
	void __iomem *base;
	unsigned i;
	int num_clks;

	num_clks = of_property_count_strings(np, "clock-output-names");

Annotation

Implementation Notes