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

   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.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
  29 static DEFINE_SPINLOCK(x3proto_gpio_lock);
  30 static struct irq_domain *x3proto_irq_domain;
  31
  32 static 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
  46 static int x3proto_gpio_get(struct gpio_chip *chip, unsigned gpio)
  47 {
  48         return !!(__raw_readw(KEYDETR) & (1 << gpio));
  49 }
  50
  51 static 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
  63 static void x3proto_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
  64 {
  65         struct irq_data *data = irq_get_irq_data(irq);
  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
  79 struct 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
  88 static 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
  97 static struct irq_domain_ops x3proto_gpio_irq_ops = {
  98         .map    = x3proto_gpio_irq_map,
  99         .xlate  = irq_domain_xlate_twocell,
 100 };
 101
 102 int __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(&x3proto_gpio_chip);
 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
 130 err_irq:
 131         ret = gpiochip_remove(&x3proto_gpio_chip);
 132         if (unlikely(ret))
 133                 pr_err("Failed deregistering GPIO\n");
 134
 135 err_gpio:
 136         synchronize_irq(ilsel);
 137
 138         ilsel_disable(ILSEL_KEY);
 139
 140         return ret;
 141 }