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  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/io.h>
  21 #include <mach/ilsel.h>
  22 #include <mach/hardware.h>
  23
  24 #define KEYCTLR 0xb81c0000
  25 #define KEYOUTR 0xb81c0002
  26 #define KEYDETR 0xb81c0004
  27
  28 static DEFINE_SPINLOCK(x3proto_gpio_lock);
  29 static unsigned int x3proto_gpio_irq_map[NR_BASEBOARD_GPIOS] = { 0, };
  30
  31 static int x3proto_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
  32 {
  33         unsigned long flags;
  34         unsigned int data;
  35
  36         spin_lock_irqsave(&x3proto_gpio_lock, flags);
  37         data = __raw_readw(KEYCTLR);
  38         data |= (1 << gpio);
  39         __raw_writew(data, KEYCTLR);
  40         spin_unlock_irqrestore(&x3proto_gpio_lock, flags);
  41
  42         return 0;
  43 }
  44
  45 static int x3proto_gpio_get(struct gpio_chip *chip, unsigned gpio)
  46 {
  47         return !!(__raw_readw(KEYDETR) & (1 << gpio));
  48 }
  49
  50 static int x3proto_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
  51 {
  52         return x3proto_gpio_irq_map[gpio];
  53 }
  54
  55 static void x3proto_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
  56 {
  57         struct irq_data *data = irq_get_irq_data(irq);
  58         struct irq_chip *chip = irq_data_get_irq_chip(data);
  59         unsigned long mask;
  60         int pin;
  61
  62         chip->irq_mask_ack(data);
  63
  64         mask = __raw_readw(KEYDETR);
  65
  66         for_each_set_bit(pin, &mask, NR_BASEBOARD_GPIOS)
  67                 generic_handle_irq(x3proto_gpio_to_irq(NULL, pin));
  68
  69         chip->irq_unmask(data);
  70 }
  71
  72 struct gpio_chip x3proto_gpio_chip = {
  73         .label                  = "x3proto-gpio",
  74         .direction_input        = x3proto_gpio_direction_input,
  75         .get                    = x3proto_gpio_get,
  76         .to_irq                 = x3proto_gpio_to_irq,
  77         .base                   = -1,
  78         .ngpio                  = NR_BASEBOARD_GPIOS,
  79 };
  80
  81 int __init x3proto_gpio_setup(void)
  82 {
  83         int ilsel;
  84         int ret, i;
  85
  86         ilsel = ilsel_enable(ILSEL_KEY);
  87         if (unlikely(ilsel < 0))
  88                 return ilsel;
  89
  90         ret = gpiochip_add(&x3proto_gpio_chip);
  91         if (unlikely(ret))
  92                 goto err_gpio;
  93
  94         for (i = 0; i < NR_BASEBOARD_GPIOS; i++) {
  95                 unsigned long flags;
  96                 int irq = create_irq();
  97
  98                 if (unlikely(irq < 0)) {
  99                         ret = -EINVAL;
 100                         goto err_irq;
 101                 }
 102
 103                 spin_lock_irqsave(&x3proto_gpio_lock, flags);
 104                 x3proto_gpio_irq_map[i] = irq;
 105                 irq_set_chip_and_handler_name(irq, &dummy_irq_chip,
 106                                               handle_simple_irq, "gpio");
 107                 spin_unlock_irqrestore(&x3proto_gpio_lock, flags);
 108         }
 109
 110         pr_info("registering '%s' support, handling GPIOs %u -> %u, "
 111                 "bound to IRQ %u\n",
 112                 x3proto_gpio_chip.label, x3proto_gpio_chip.base,
 113                 x3proto_gpio_chip.base + x3proto_gpio_chip.ngpio,
 114                 ilsel);
 115
 116         irq_set_chained_handler(ilsel, x3proto_gpio_irq_handler);
 117         irq_set_irq_wake(ilsel, 1);
 118
 119         return 0;
 120
 121 err_irq:
 122         for (; i >= 0; --i)
 123                 if (x3proto_gpio_irq_map[i])
 124                         destroy_irq(x3proto_gpio_irq_map[i]);
 125
 126         ret = gpiochip_remove(&x3proto_gpio_chip);
 127         if (unlikely(ret))
 128                 pr_err("Failed deregistering GPIO\n");
 129
 130 err_gpio:
 131         synchronize_irq(ilsel);
 132
 133         ilsel_disable(ILSEL_KEY);
 134
 135         return ret;
 136 }