arch/sh/boards/mach-x3proto/gpio.c

Source file repositories/reference/linux-study-clean/arch/sh/boards/mach-x3proto/gpio.c

File Facts

System
Linux kernel
Corpus path
arch/sh/boards/mach-x3proto/gpio.c
Extension
.c
Size
3091 bytes
Lines
137
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/boards/mach-x3proto/gpio.c
 *
 * Renesas SH-X3 Prototype Baseboard GPIO Support.
 *
 * Copyright (C) 2010 - 2012  Paul Mundt
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/gpio/driver.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/irqdomain.h>
#include <linux/io.h>
#include <mach/ilsel.h>
#include <mach/hardware.h>

#define KEYCTLR	0xb81c0000
#define KEYOUTR	0xb81c0002
#define KEYDETR 0xb81c0004

static DEFINE_SPINLOCK(x3proto_gpio_lock);
static struct irq_domain *x3proto_irq_domain;

static int x3proto_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
{
	unsigned long flags;
	unsigned int data;

	spin_lock_irqsave(&x3proto_gpio_lock, flags);
	data = __raw_readw(KEYCTLR);
	data |= (1 << gpio);
	__raw_writew(data, KEYCTLR);
	spin_unlock_irqrestore(&x3proto_gpio_lock, flags);

	return 0;
}

static int x3proto_gpio_get(struct gpio_chip *chip, unsigned gpio)
{
	return !!(__raw_readw(KEYDETR) & (1 << gpio));
}

static int x3proto_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
{
	int virq;

	if (gpio < chip->ngpio)
		virq = irq_create_mapping(x3proto_irq_domain, gpio);
	else
		virq = -ENXIO;

	return virq;
}

static void x3proto_gpio_irq_handler(struct irq_desc *desc)
{
	struct irq_data *data = irq_desc_get_irq_data(desc);
	struct irq_chip *chip = irq_data_get_irq_chip(data);
	unsigned long mask;
	int pin;

	chip->irq_mask_ack(data);

	mask = __raw_readw(KEYDETR);
	for_each_set_bit(pin, &mask, NR_BASEBOARD_GPIOS)
		generic_handle_domain_irq(x3proto_irq_domain, pin);

	chip->irq_unmask(data);
}

struct gpio_chip x3proto_gpio_chip = {
	.label			= "x3proto-gpio",
	.direction_input	= x3proto_gpio_direction_input,
	.get			= x3proto_gpio_get,
	.to_irq			= x3proto_gpio_to_irq,
	.base			= -1,
	.ngpio			= NR_BASEBOARD_GPIOS,
};

static int x3proto_gpio_irq_map(struct irq_domain *domain, unsigned int virq,
				irq_hw_number_t hwirq)
{
	irq_set_chip_and_handler_name(virq, &dummy_irq_chip, handle_simple_irq,
				      "gpio");

Annotation

Implementation Notes