linux/arch/x86/mach-rdc321x/gpio.c
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   1/*
   2 *  GPIO support for RDC SoC R3210/R8610
   3 *
   4 *  Copyright (C) 2007, Florian Fainelli <florian@openwrt.org>
   5 *  Copyright (C) 2008, Volker Weiss <dev@tintuc.de>
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License as published by
   9 * the Free Software Foundation; either version 2 of the License, or
  10 * (at your option) any later version.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this program; if not, write to the Free Software
  19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 *
  21 */
  22
  23
  24#include <linux/spinlock.h>
  25#include <linux/io.h>
  26#include <linux/types.h>
  27#include <linux/module.h>
  28
  29#include <asm/gpio.h>
  30#include <asm/mach-rdc321x/rdc321x_defs.h>
  31
  32
  33/* spin lock to protect our private copy of GPIO data register plus
  34   the access to PCI conf registers. */
  35static DEFINE_SPINLOCK(gpio_lock);
  36
  37/* copy of GPIO data registers */
  38static u32 gpio_data_reg1;
  39static u32 gpio_data_reg2;
  40
  41static u32 gpio_request_data[2];
  42
  43
  44static inline void rdc321x_conf_write(unsigned addr, u32 value)
  45{
  46        outl((1 << 31) | (7 << 11) | addr, RDC3210_CFGREG_ADDR);
  47        outl(value, RDC3210_CFGREG_DATA);
  48}
  49
  50static inline void rdc321x_conf_or(unsigned addr, u32 value)
  51{
  52        outl((1 << 31) | (7 << 11) | addr, RDC3210_CFGREG_ADDR);
  53        value |= inl(RDC3210_CFGREG_DATA);
  54        outl(value, RDC3210_CFGREG_DATA);
  55}
  56
  57static inline u32 rdc321x_conf_read(unsigned addr)
  58{
  59        outl((1 << 31) | (7 << 11) | addr, RDC3210_CFGREG_ADDR);
  60
  61        return inl(RDC3210_CFGREG_DATA);
  62}
  63
  64/* configure pin as GPIO */
  65static void rdc321x_configure_gpio(unsigned gpio)
  66{
  67        unsigned long flags;
  68
  69        spin_lock_irqsave(&gpio_lock, flags);
  70        rdc321x_conf_or(gpio < 32
  71                ? RDC321X_GPIO_CTRL_REG1 : RDC321X_GPIO_CTRL_REG2,
  72                1 << (gpio & 0x1f));
  73        spin_unlock_irqrestore(&gpio_lock, flags);
  74}
  75
  76/* initially setup the 2 copies of the gpio data registers.
  77   This function must be called by the platform setup code. */
  78void __init rdc321x_gpio_setup()
  79{
  80        /* this might not be, what others (BIOS, bootloader, etc.)
  81           wrote to these registers before, but it's a good guess. Still
  82           better than just using 0xffffffff. */
  83
  84        gpio_data_reg1 = rdc321x_conf_read(RDC321X_GPIO_DATA_REG1);
  85        gpio_data_reg2 = rdc321x_conf_read(RDC321X_GPIO_DATA_REG2);
  86}
  87
  88/* determine, if gpio number is valid */
  89static inline int rdc321x_is_gpio(unsigned gpio)
  90{
  91        return gpio <= RDC321X_MAX_GPIO;
  92}
  93
  94/* request GPIO */
  95int rdc_gpio_request(unsigned gpio, const char *label)
  96{
  97        unsigned long flags;
  98
  99        if (!rdc321x_is_gpio(gpio))
 100                return -EINVAL;
 101
 102        spin_lock_irqsave(&gpio_lock, flags);
 103        if (gpio_request_data[(gpio & 0x20) ? 1 : 0] & (1 << (gpio & 0x1f)))
 104                goto inuse;
 105        gpio_request_data[(gpio & 0x20) ? 1 : 0] |= (1 << (gpio & 0x1f));
 106        spin_unlock_irqrestore(&gpio_lock, flags);
 107
 108        return 0;
 109inuse:
 110        spin_unlock_irqrestore(&gpio_lock, flags);
 111        return -EINVAL;
 112}
 113EXPORT_SYMBOL(rdc_gpio_request);
 114
 115/* release previously-claimed GPIO */
 116void rdc_gpio_free(unsigned gpio)
 117{
 118        unsigned long flags;
 119
 120        if (!rdc321x_is_gpio(gpio))
 121                return;
 122
 123        spin_lock_irqsave(&gpio_lock, flags);
 124        gpio_request_data[(gpio & 0x20) ? 1 : 0] &= ~(1 << (gpio & 0x1f));
 125        spin_unlock_irqrestore(&gpio_lock, flags);
 126}
 127EXPORT_SYMBOL(rdc_gpio_free);
 128
 129/* read GPIO pin */
 130int rdc_gpio_get_value(unsigned gpio)
 131{
 132        u32 reg;
 133        unsigned long flags;
 134
 135        spin_lock_irqsave(&gpio_lock, flags);
 136        reg = rdc321x_conf_read(gpio < 32
 137                ? RDC321X_GPIO_DATA_REG1 : RDC321X_GPIO_DATA_REG2);
 138        spin_unlock_irqrestore(&gpio_lock, flags);
 139
 140        return (1 << (gpio & 0x1f)) & reg ? 1 : 0;
 141}
 142EXPORT_SYMBOL(rdc_gpio_get_value);
 143
 144/* set GPIO pin to value */
 145void rdc_gpio_set_value(unsigned gpio, int value)
 146{
 147        unsigned long flags;
 148        u32 reg;
 149
 150        reg = 1 << (gpio & 0x1f);
 151        if (gpio < 32) {
 152                spin_lock_irqsave(&gpio_lock, flags);
 153                if (value)
 154                        gpio_data_reg1 |= reg;
 155                else
 156                        gpio_data_reg1 &= ~reg;
 157                rdc321x_conf_write(RDC321X_GPIO_DATA_REG1, gpio_data_reg1);
 158                spin_unlock_irqrestore(&gpio_lock, flags);
 159        } else {
 160                spin_lock_irqsave(&gpio_lock, flags);
 161                if (value)
 162                        gpio_data_reg2 |= reg;
 163                else
 164                        gpio_data_reg2 &= ~reg;
 165                rdc321x_conf_write(RDC321X_GPIO_DATA_REG2, gpio_data_reg2);
 166                spin_unlock_irqrestore(&gpio_lock, flags);
 167        }
 168}
 169EXPORT_SYMBOL(rdc_gpio_set_value);
 170
 171/* configure GPIO pin as input */
 172int rdc_gpio_direction_input(unsigned gpio)
 173{
 174        if (!rdc321x_is_gpio(gpio))
 175                return -EINVAL;
 176
 177        rdc321x_configure_gpio(gpio);
 178
 179        return 0;
 180}
 181EXPORT_SYMBOL(rdc_gpio_direction_input);
 182
 183/* configure GPIO pin as output and set value */
 184int rdc_gpio_direction_output(unsigned gpio, int value)
 185{
 186        if (!rdc321x_is_gpio(gpio))
 187                return -EINVAL;
 188
 189        gpio_set_value(gpio, value);
 190        rdc321x_configure_gpio(gpio);
 191
 192        return 0;
 193}
 194EXPORT_SYMBOL(rdc_gpio_direction_output);
 195