drivers/gpio/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 #include <linux/mfd/rdc321x.h>
  30 #include <linux/mfd/core.h>
  31 #include <linux/slab.h>
  32
  33 struct rdc321x_gpio {
  34         spinlock_t              lock;
  35         struct pci_dev          *sb_pdev;
  36         u32                     data_reg[2];
  37         int                     reg1_ctrl_base;
  38         int                     reg1_data_base;
  39         int                     reg2_ctrl_base;
  40         int                     reg2_data_base;
  41         struct gpio_chip        chip;
  42 };
  43
  44 /* read GPIO pin */
  45 static int rdc_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
  46 {
  47         struct rdc321x_gpio *gpch;
  48         u32 value = 0;
  49         int reg;
  50
  51         gpch = container_of(chip, struct rdc321x_gpio, chip);
  52         reg = gpio < 32 ? gpch->reg1_data_base : gpch->reg2_data_base;
  53
  54         spin_lock(&gpch->lock);
  55         pci_write_config_dword(gpch->sb_pdev, reg,
  56                                         gpch->data_reg[gpio < 32 ? 0 : 1]);
  57         pci_read_config_dword(gpch->sb_pdev, reg, &value);
  58         spin_unlock(&gpch->lock);
  59
  60         return (1 << (gpio & 0x1f)) & value ? 1 : 0;
  61 }
  62
  63 static void rdc_gpio_set_value_impl(struct gpio_chip *chip,
  64                                 unsigned gpio, int value)
  65 {
  66         struct rdc321x_gpio *gpch;
  67         int reg = (gpio < 32) ? 0 : 1;
  68
  69         gpch = container_of(chip, struct rdc321x_gpio, chip);
  70
  71         if (value)
  72                 gpch->data_reg[reg] |= 1 << (gpio & 0x1f);
  73         else
  74                 gpch->data_reg[reg] &= ~(1 << (gpio & 0x1f));
  75
  76         pci_write_config_dword(gpch->sb_pdev,
  77                         reg ? gpch->reg2_data_base : gpch->reg1_data_base,
  78                         gpch->data_reg[reg]);
  79 }
  80
  81 /* set GPIO pin to value */
  82 static void rdc_gpio_set_value(struct gpio_chip *chip,
  83                                 unsigned gpio, int value)
  84 {
  85         struct rdc321x_gpio *gpch;
  86
  87         gpch = container_of(chip, struct rdc321x_gpio, chip);
  88         spin_lock(&gpch->lock);
  89         rdc_gpio_set_value_impl(chip, gpio, value);
  90         spin_unlock(&gpch->lock);
  91 }
  92
  93 static int rdc_gpio_config(struct gpio_chip *chip,
  94                                 unsigned gpio, int value)
  95 {
  96         struct rdc321x_gpio *gpch;
  97         int err;
  98         u32 reg;
  99
 100         gpch = container_of(chip, struct rdc321x_gpio, chip);
 101
 102         spin_lock(&gpch->lock);
 103         err = pci_read_config_dword(gpch->sb_pdev, gpio < 32 ?
 104                         gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, &reg);
 105         if (err)
 106                 goto unlock;
 107
 108         reg |= 1 << (gpio & 0x1f);
 109
 110         err = pci_write_config_dword(gpch->sb_pdev, gpio < 32 ?
 111                         gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, reg);
 112         if (err)
 113                 goto unlock;
 114
 115         rdc_gpio_set_value_impl(chip, gpio, value);
 116
 117 unlock:
 118         spin_unlock(&gpch->lock);
 119
 120         return err;
 121 }
 122
 123 /* configure GPIO pin as input */
 124 static int rdc_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
 125 {
 126         return rdc_gpio_config(chip, gpio, 1);
 127 }
 128
 129 /*
 130  * Cache the initial value of both GPIO data registers
 131  */
 132 static int __devinit rdc321x_gpio_probe(struct platform_device *pdev)
 133 {
 134         int err;
 135         struct resource *r;
 136         struct rdc321x_gpio *rdc321x_gpio_dev;
 137         struct rdc321x_gpio_pdata *pdata;
 138
 139         pdata = mfd_get_data(pdev);
 140         if (!pdata) {
 141                 dev_err(&pdev->dev, "no platform data supplied\n");
 142                 return -ENODEV;
 143         }
 144
 145         rdc321x_gpio_dev = kzalloc(sizeof(struct rdc321x_gpio), GFP_KERNEL);
 146         if (!rdc321x_gpio_dev) {
 147                 dev_err(&pdev->dev, "failed to allocate private data\n");
 148                 return -ENOMEM;
 149         }
 150
 151         r = platform_get_resource_byname(pdev, IORESOURCE_IO, "gpio-reg1");
 152         if (!r) {
 153                 dev_err(&pdev->dev, "failed to get gpio-reg1 resource\n");
 154                 err = -ENODEV;
 155                 goto out_free;
 156         }
 157
 158         spin_lock_init(&rdc321x_gpio_dev->lock);
 159         rdc321x_gpio_dev->sb_pdev = pdata->sb_pdev;
 160         rdc321x_gpio_dev->reg1_ctrl_base = r->start;
 161         rdc321x_gpio_dev->reg1_data_base = r->start + 0x4;
 162
 163         r = platform_get_resource_byname(pdev, IORESOURCE_IO, "gpio-reg2");
 164         if (!r) {
 165                 dev_err(&pdev->dev, "failed to get gpio-reg2 resource\n");
 166                 err = -ENODEV;
 167                 goto out_free;
 168         }
 169
 170         rdc321x_gpio_dev->reg2_ctrl_base = r->start;
 171         rdc321x_gpio_dev->reg2_data_base = r->start + 0x4;
 172
 173         rdc321x_gpio_dev->chip.label = "rdc321x-gpio";
 174         rdc321x_gpio_dev->chip.direction_input = rdc_gpio_direction_input;
 175         rdc321x_gpio_dev->chip.direction_output = rdc_gpio_config;
 176         rdc321x_gpio_dev->chip.get = rdc_gpio_get_value;
 177         rdc321x_gpio_dev->chip.set = rdc_gpio_set_value;
 178         rdc321x_gpio_dev->chip.base = 0;
 179         rdc321x_gpio_dev->chip.ngpio = pdata->max_gpios;
 180
 181         platform_set_drvdata(pdev, rdc321x_gpio_dev);
 182
 183         /* This might not be, what others (BIOS, bootloader, etc.)
 184            wrote to these registers before, but it's a good guess. Still
 185            better than just using 0xffffffff. */
 186         err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev,
 187                                         rdc321x_gpio_dev->reg1_data_base,
 188                                         &rdc321x_gpio_dev->data_reg[0]);
 189         if (err)
 190                 goto out_drvdata;
 191
 192         err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev,
 193                                         rdc321x_gpio_dev->reg2_data_base,
 194                                         &rdc321x_gpio_dev->data_reg[1]);
 195         if (err)
 196                 goto out_drvdata;
 197
 198         dev_info(&pdev->dev, "registering %d GPIOs\n",
 199                                         rdc321x_gpio_dev->chip.ngpio);
 200         return gpiochip_add(&rdc321x_gpio_dev->chip);
 201
 202 out_drvdata:
 203         platform_set_drvdata(pdev, NULL);
 204 out_free:
 205         kfree(rdc321x_gpio_dev);
 206         return err;
 207 }
 208
 209 static int __devexit rdc321x_gpio_remove(struct platform_device *pdev)
 210 {
 211         int ret;
 212         struct rdc321x_gpio *rdc321x_gpio_dev = platform_get_drvdata(pdev);
 213
 214         ret = gpiochip_remove(&rdc321x_gpio_dev->chip);
 215         if (ret)
 216                 dev_err(&pdev->dev, "failed to unregister chip\n");
 217
 218         kfree(rdc321x_gpio_dev);
 219         platform_set_drvdata(pdev, NULL);
 220
 221         return ret;
 222 }
 223
 224 static struct platform_driver rdc321x_gpio_driver = {
 225         .driver.name    = "rdc321x-gpio",
 226         .driver.owner   = THIS_MODULE,
 227         .probe          = rdc321x_gpio_probe,
 228         .remove         = __devexit_p(rdc321x_gpio_remove),
 229 };
 230
 231 static int __init rdc321x_gpio_init(void)
 232 {
 233         return platform_driver_register(&rdc321x_gpio_driver);
 234 }
 235
 236 static void __exit rdc321x_gpio_exit(void)
 237 {
 238         platform_driver_unregister(&rdc321x_gpio_driver);
 239 }
 240
 241 module_init(rdc321x_gpio_init);
 242 module_exit(rdc321x_gpio_exit);
 243
 244 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 245 MODULE_DESCRIPTION("RDC321x GPIO driver");
 246 MODULE_LICENSE("GPL");
 247 MODULE_ALIAS("platform:rdc321x-gpio");