linux/arch/sh/boards/mach-x3proto/gpio.c
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   1/*
   2 * arch/sh/boards/mach-x3proto/gpio.c
   3 *
   4 * Renesas SH-X3 Prototype Baseboard GPIO Support.
   5 *
   6 * Copyright (C) 2010 - 2012  Paul Mundt
   7 *
   8 * This file is subject to the terms and conditions of the GNU General Public
   9 * License.  See the file "COPYING" in the main directory of this archive
  10 * for more details.
  11 */
  12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14#include <linux/init.h>
  15#include <linux/interrupt.h>
  16#include <linux/gpio/driver.h>
  17#include <linux/irq.h>
  18#include <linux/kernel.h>
  19#include <linux/spinlock.h>
  20#include <linux/irqdomain.h>
  21#include <linux/io.h>
  22#include <mach/ilsel.h>
  23#include <mach/hardware.h>
  24
  25#define KEYCTLR 0xb81c0000
  26#define KEYOUTR 0xb81c0002
  27#define KEYDETR 0xb81c0004
  28
  29static DEFINE_SPINLOCK(x3proto_gpio_lock);
  30static struct irq_domain *x3proto_irq_domain;
  31
  32static int x3proto_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
  33{
  34        unsigned long flags;
  35        unsigned int data;
  36
  37        spin_lock_irqsave(&x3proto_gpio_lock, flags);
  38        data = __raw_readw(KEYCTLR);
  39        data |= (1 << gpio);
  40        __raw_writew(data, KEYCTLR);
  41        spin_unlock_irqrestore(&x3proto_gpio_lock, flags);
  42
  43        return 0;
  44}
  45
  46static int x3proto_gpio_get(struct gpio_chip *chip, unsigned gpio)
  47{
  48        return !!(__raw_readw(KEYDETR) & (1 << gpio));
  49}
  50
  51static int x3proto_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
  52{
  53        int virq;
  54
  55        if (gpio < chip->ngpio)
  56                virq = irq_create_mapping(x3proto_irq_domain, gpio);
  57        else
  58                virq = -ENXIO;
  59
  60        return virq;
  61}
  62
  63static void x3proto_gpio_irq_handler(struct irq_desc *desc)
  64{
  65        struct irq_data *data = irq_desc_get_irq_data(desc);
  66        struct irq_chip *chip = irq_data_get_irq_chip(data);
  67        unsigned long mask;
  68        int pin;
  69
  70        chip->irq_mask_ack(data);
  71
  72        mask = __raw_readw(KEYDETR);
  73        for_each_set_bit(pin, &mask, NR_BASEBOARD_GPIOS)
  74                generic_handle_irq(irq_linear_revmap(x3proto_irq_domain, pin));
  75
  76        chip->irq_unmask(data);
  77}
  78
  79struct gpio_chip x3proto_gpio_chip = {
  80        .label                  = "x3proto-gpio",
  81        .direction_input        = x3proto_gpio_direction_input,
  82        .get                    = x3proto_gpio_get,
  83        .to_irq                 = x3proto_gpio_to_irq,
  84        .base                   = -1,
  85        .ngpio                  = NR_BASEBOARD_GPIOS,
  86};
  87
  88static int x3proto_gpio_irq_map(struct irq_domain *domain, unsigned int virq,
  89                                irq_hw_number_t hwirq)
  90{
  91        irq_set_chip_and_handler_name(virq, &dummy_irq_chip, handle_simple_irq,
  92                                      "gpio");
  93
  94        return 0;
  95}
  96
  97static struct irq_domain_ops x3proto_gpio_irq_ops = {
  98        .map    = x3proto_gpio_irq_map,
  99        .xlate  = irq_domain_xlate_twocell,
 100};
 101
 102int __init x3proto_gpio_setup(void)
 103{
 104        int ilsel, ret;
 105
 106        ilsel = ilsel_enable(ILSEL_KEY);
 107        if (unlikely(ilsel < 0))
 108                return ilsel;
 109
 110        ret = gpiochip_add_data(&x3proto_gpio_chip, NULL);
 111        if (unlikely(ret))
 112                goto err_gpio;
 113
 114        x3proto_irq_domain = irq_domain_add_linear(NULL, NR_BASEBOARD_GPIOS,
 115                                                   &x3proto_gpio_irq_ops, NULL);
 116        if (unlikely(!x3proto_irq_domain))
 117                goto err_irq;
 118
 119        pr_info("registering '%s' support, handling GPIOs %u -> %u, "
 120                "bound to IRQ %u\n",
 121                x3proto_gpio_chip.label, x3proto_gpio_chip.base,
 122                x3proto_gpio_chip.base + x3proto_gpio_chip.ngpio,
 123                ilsel);
 124
 125        irq_set_chained_handler(ilsel, x3proto_gpio_irq_handler);
 126        irq_set_irq_wake(ilsel, 1);
 127
 128        return 0;
 129
 130err_irq:
 131        gpiochip_remove(&x3proto_gpio_chip);
 132        ret = 0;
 133err_gpio:
 134        synchronize_irq(ilsel);
 135
 136        ilsel_disable(ILSEL_KEY);
 137
 138        return ret;
 139}
 140