LXR linux/arch/mips/rb532/gpio.c

   1/*
   2 *  Miscellaneous functions for IDT EB434 board
   3 *
   4 *  Copyright 2004 IDT Inc. (rischelp@idt.com)
   5 *  Copyright 2006 Phil Sutter <n0-1@freewrt.org>
   6 *  Copyright 2007 Florian Fainelli <florian@openwrt.org>
   7 *
   8 *  This program is free software; you can redistribute  it and/or modify it
   9 *  under  the terms of  the GNU General  Public License as published by the
  10 *  Free Software Foundation;  either version 2 of the  License, or (at your
  11 *  option) any later version.
  12 *
  13 *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
  14 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
  15 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  16 *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
  17 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  18 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
  19 *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  20 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
  21 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  22 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  23 *
  24 *  You should have received a copy of the  GNU General Public License along
  25 *  with this program; if not, write  to the Free Software Foundation, Inc.,
  26 *  675 Mass Ave, Cambridge, MA 02139, USA.
  27 */
  28
  29#include <linux/kernel.h>
  30#include <linux/init.h>
  31#include <linux/types.h>
  32#include <linux/spinlock.h>
  33#include <linux/platform_device.h>
  34#include <linux/gpio.h>
  35
  36#include <asm/mach-rc32434/rb.h>
  37#include <asm/mach-rc32434/gpio.h>
  38
  39struct rb532_gpio_chip {
  40        struct gpio_chip chip;
  41        void __iomem     *regbase;
  42};
  43
  44static struct resource rb532_gpio_reg0_res[] = {
  45        {
  46                .name   = "gpio_reg0",
  47                .start  = REGBASE + GPIOBASE,
  48                .end    = REGBASE + GPIOBASE + sizeof(struct rb532_gpio_reg) - 1,
  49                .flags  = IORESOURCE_MEM,
  50        }
  51};
  52
  53/* rb532_set_bit - sanely set a bit
  54 *
  55 * bitval: new value for the bit
  56 * offset: bit index in the 4 byte address range
  57 * ioaddr: 4 byte aligned address being altered
  58 */
  59static inline void rb532_set_bit(unsigned bitval,
  60                unsigned offset, void __iomem *ioaddr)
  61{
  62        unsigned long flags;
  63        u32 val;
  64
  65        local_irq_save(flags);
  66
  67        val = readl(ioaddr);
  68        val &= ~(!bitval << offset);   /* unset bit if bitval == 0 */
  69        val |= (!!bitval << offset);   /* set bit if bitval == 1 */
  70        writel(val, ioaddr);
  71
  72        local_irq_restore(flags);
  73}
  74
  75/* rb532_get_bit - read a bit
  76 *
  77 * returns the boolean state of the bit, which may be > 1
  78 */
  79static inline int rb532_get_bit(unsigned offset, void __iomem *ioaddr)
  80{
  81        return (readl(ioaddr) & (1 << offset));
  82}
  83
  84/*
  85 * Return GPIO level */
  86static int rb532_gpio_get(struct gpio_chip *chip, unsigned offset)
  87{
  88        struct rb532_gpio_chip  *gpch;
  89
  90        gpch = container_of(chip, struct rb532_gpio_chip, chip);
  91        return rb532_get_bit(offset, gpch->regbase + GPIOD);
  92}
  93
  94/*
  95 * Set output GPIO level
  96 */
  97static void rb532_gpio_set(struct gpio_chip *chip,
  98                                unsigned offset, int value)
  99{
 100        struct rb532_gpio_chip  *gpch;
 101
 102        gpch = container_of(chip, struct rb532_gpio_chip, chip);
 103        rb532_set_bit(value, offset, gpch->regbase + GPIOD);
 104}
 105
 106/*
 107 * Set GPIO direction to input
 108 */
 109static int rb532_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 110{
 111        struct rb532_gpio_chip  *gpch;
 112
 113        gpch = container_of(chip, struct rb532_gpio_chip, chip);
 114
 115        /* disable alternate function in case it's set */
 116        rb532_set_bit(0, offset, gpch->regbase + GPIOFUNC);
 117
 118        rb532_set_bit(0, offset, gpch->regbase + GPIOCFG);
 119        return 0;
 120}
 121
 122/*
 123 * Set GPIO direction to output
 124 */
 125static int rb532_gpio_direction_output(struct gpio_chip *chip,
 126                                        unsigned offset, int value)
 127{
 128        struct rb532_gpio_chip  *gpch;
 129
 130        gpch = container_of(chip, struct rb532_gpio_chip, chip);
 131
 132        /* disable alternate function in case it's set */
 133        rb532_set_bit(0, offset, gpch->regbase + GPIOFUNC);
 134
 135        /* set the initial output value */
 136        rb532_set_bit(value, offset, gpch->regbase + GPIOD);
 137
 138        rb532_set_bit(1, offset, gpch->regbase + GPIOCFG);
 139        return 0;
 140}
 141
 142static struct rb532_gpio_chip rb532_gpio_chip[] = {
 143        [0] = {
 144                .chip = {
 145                        .label                  = "gpio0",
 146                        .direction_input        = rb532_gpio_direction_input,
 147                        .direction_output       = rb532_gpio_direction_output,
 148                        .get                    = rb532_gpio_get,
 149                        .set                    = rb532_gpio_set,
 150                        .base                   = 0,
 151                        .ngpio                  = 32,
 152                },
 153        },
 154};
 155
 156/*
 157 * Set GPIO interrupt level
 158 */
 159void rb532_gpio_set_ilevel(int bit, unsigned gpio)
 160{
 161        rb532_set_bit(bit, gpio, rb532_gpio_chip->regbase + GPIOILEVEL);
 162}
 163EXPORT_SYMBOL(rb532_gpio_set_ilevel);
 164
 165/*
 166 * Set GPIO interrupt status
 167 */
 168void rb532_gpio_set_istat(int bit, unsigned gpio)
 169{
 170        rb532_set_bit(bit, gpio, rb532_gpio_chip->regbase + GPIOISTAT);
 171}
 172EXPORT_SYMBOL(rb532_gpio_set_istat);
 173
 174/*
 175 * Configure GPIO alternate function
 176 */
 177void rb532_gpio_set_func(unsigned gpio)
 178{
 179       rb532_set_bit(1, gpio, rb532_gpio_chip->regbase + GPIOFUNC);
 180}
 181EXPORT_SYMBOL(rb532_gpio_set_func);
 182
 183int __init rb532_gpio_init(void)
 184{
 185        struct resource *r;
 186
 187        r = rb532_gpio_reg0_res;
 188        rb532_gpio_chip->regbase = ioremap_nocache(r->start, resource_size(r));
 189
 190        if (!rb532_gpio_chip->regbase) {
 191                printk(KERN_ERR "rb532: cannot remap GPIO register 0\n");
 192                return -ENXIO;
 193        }
 194
 195        /* Register our GPIO chip */
 196        gpiochip_add(&rb532_gpio_chip->chip);
 197
 198        return 0;
 199}
 200arch_initcall(rb532_gpio_init);
 201