target/linux/rdc/files-2.6.30/arch/x86/mach-rdc321x/gpio.c

   1 /*
   2  * RDC321x GPIO driver
   3  *
   4  * Copyright (C) 2008, Volker Weiss <dev@tintuc.de>
   5  * Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>
   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 #include <linux/module.h>
  23 #include <linux/kernel.h>
  24 #include <linux/init.h>
  25 #include <linux/spinlock.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/pci.h>
  28 #include <linux/gpio.h>
  29
  30 #include <asm/rdc321x_defs.h>
  31
  32 struct rdc321x_gpio {
  33         spinlock_t      lock;
  34         u32             data_reg[2];
  35 } rdc321x_gpio_dev;
  36
  37 extern int rdc321x_pci_write(int reg, u32 val);
  38 extern int rdc321x_pci_read(int reg, u32 *val);
  39
  40 /* read GPIO pin */
  41 static int rdc_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
  42 {
  43         u32 value = 0;
  44         int reg;
  45
  46         reg = gpio < 32 ? RDC321X_GPIO_DATA_REG1 : RDC321X_GPIO_DATA_REG2;
  47
  48         spin_lock(&rdc321x_gpio_dev.lock);
  49         rdc321x_pci_write(reg, rdc321x_gpio_dev.data_reg[gpio < 32 ? 0 : 1]);
  50         rdc321x_pci_read(reg, &value);
  51         spin_unlock(&rdc321x_gpio_dev.lock);
  52
  53         return (1 << (gpio & 0x1f)) & value ? 1 : 0;
  54 }
  55
  56 static void rdc_gpio_set_value_impl(struct gpio_chip *chip,
  57                                 unsigned gpio, int value)
  58 {
  59         int reg = (gpio < 32) ? 0 : 1;
  60
  61         if (value)
  62                 rdc321x_gpio_dev.data_reg[reg] |= 1 << (gpio & 0x1f);
  63         else
  64                 rdc321x_gpio_dev.data_reg[reg] &= ~(1 << (gpio & 0x1f));
  65
  66         rdc321x_pci_write(reg ? RDC321X_GPIO_DATA_REG2 : RDC321X_GPIO_DATA_REG1,
  67                                rdc321x_gpio_dev.data_reg[reg]);
  68 }
  69
  70 /* set GPIO pin to value */
  71 static void rdc_gpio_set_value(struct gpio_chip *chip,
  72                                 unsigned gpio, int value)
  73 {
  74         spin_lock(&rdc321x_gpio_dev.lock);
  75         rdc_gpio_set_value_impl(chip, gpio, value);
  76         spin_unlock(&rdc321x_gpio_dev.lock);
  77 }
  78
  79 static int rdc_gpio_config(struct gpio_chip *chip,
  80                                 unsigned gpio, int value)
  81 {
  82         int err;
  83         u32 reg;
  84
  85         spin_lock(&rdc321x_gpio_dev.lock);
  86         err = rdc321x_pci_read(gpio < 32 ? RDC321X_GPIO_CTRL_REG1 : RDC321X_GPIO_CTRL_REG2,
  87                                                                                 &reg);
  88         if (err)
  89                 goto unlock;
  90
  91         reg |= 1 << (gpio & 0x1f);
  92
  93         err = rdc321x_pci_write(gpio < 32 ? RDC321X_GPIO_CTRL_REG1 : RDC321X_GPIO_CTRL_REG2,
  94                                                                                 reg);
  95         if (err)
  96                 goto unlock;
  97
  98         rdc_gpio_set_value_impl(chip, gpio, value);
  99
 100 unlock:
 101         spin_unlock(&rdc321x_gpio_dev.lock);
 102
 103         return err;
 104 }
 105
 106 /* configure GPIO pin as input */
 107 static int rdc_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
 108 {
 109         return rdc_gpio_config(chip, gpio, 1);
 110 }
 111
 112 static struct gpio_chip rdc321x_gpio_chip = {
 113         .label                  = "rdc321x-gpio",
 114         .direction_input        = rdc_gpio_direction_input,
 115         .direction_output       = rdc_gpio_config,
 116         .get                    = rdc_gpio_get_value,
 117         .set                    = rdc_gpio_set_value,
 118         .base                   = 0,
 119         .ngpio                  = RDC321X_MAX_GPIO,
 120 };
 121
 122 /* initially setup the 2 copies of the gpio data registers.
 123    This function is called before the platform setup code. */
 124 static int __devinit rdc321x_gpio_probe(struct platform_device *pdev)
 125 {
 126         int err;
 127
 128         /* this might not be, what others (BIOS, bootloader, etc.)
 129            wrote to these registers before, but it's a good guess. Still
 130            better than just using 0xffffffff. */
 131         err = rdc321x_pci_read(RDC321X_GPIO_DATA_REG1, &rdc321x_gpio_dev.data_reg[0]);
 132         if (err)
 133                 return err;
 134
 135         err = rdc321x_pci_read(RDC321X_GPIO_DATA_REG2, &rdc321x_gpio_dev.data_reg[1]);
 136         if (err)
 137                 return err;
 138
 139         spin_lock_init(&rdc321x_gpio_dev.lock);
 140
 141         printk(KERN_INFO "rdc321x: registering %d GPIOs\n", rdc321x_gpio_chip.ngpio);
 142         return gpiochip_add(&rdc321x_gpio_chip);
 143 }
 144
 145 static int __devexit rdc321x_gpio_remove(struct platform_device *pdev)
 146 {
 147         gpiochip_remove(&rdc321x_gpio_chip);
 148         return 0;
 149 }
 150
 151 static struct platform_driver rdc321x_gpio_driver = {
 152         .driver.name    = "rdc321x-gpio",
 153         .driver.owner   = THIS_MODULE,
 154         .probe          = rdc321x_gpio_probe,
 155         .remove         = __devexit_p(rdc321x_gpio_remove),
 156 };
 157
 158 static int __init rdc321x_gpio_init(void)
 159 {
 160         return platform_driver_register(&rdc321x_gpio_driver);
 161 }
 162
 163 static void __exit rdc321x_gpio_exit(void)
 164 {
 165         platform_driver_unregister(&rdc321x_gpio_driver);
 166 }
 167
 168 module_init(rdc321x_gpio_init);
 169 module_exit(rdc321x_gpio_exit);
 170
 171 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 172 MODULE_DESCRIPTION("RDC321x GPIO driver");
 173 MODULE_LICENSE("GPL");
 174 MODULE_ALIAS("platform:rdc321x-gpio");