drivers/gpio/gpio-rdc321x.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/slab.h>
  31
  32 struct rdc321x_gpio {
  33         spinlock_t              lock;
  34         struct pci_dev          *sb_pdev;
  35         u32                     data_reg[2];
  36         int                     reg1_ctrl_base;
  37         int                     reg1_data_base;
  38         int                     reg2_ctrl_base;
  39         int                     reg2_data_base;
  40         struct gpio_chip        chip;
  41 };
  42
  43 /* read GPIO pin */
  44 static int rdc_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
  45 {
  46         struct rdc321x_gpio *gpch;
  47         u32 value = 0;
  48         int reg;
  49
  50         gpch = container_of(chip, struct rdc321x_gpio, chip);
  51         reg = gpio < 32 ? gpch->reg1_data_base : gpch->reg2_data_base;
  52
  53         spin_lock(&gpch->lock);
  54         pci_write_config_dword(gpch->sb_pdev, reg,
  55                                         gpch->data_reg[gpio < 32 ? 0 : 1]);
  56         pci_read_config_dword(gpch->sb_pdev, reg, &value);
  57         spin_unlock(&gpch->lock);
  58
  59         return (1 << (gpio & 0x1f)) & value ? 1 : 0;
  60 }
  61
  62 static void rdc_gpio_set_value_impl(struct gpio_chip *chip,
  63                                 unsigned gpio, int value)
  64 {
  65         struct rdc321x_gpio *gpch;
  66         int reg = (gpio < 32) ? 0 : 1;
  67
  68         gpch = container_of(chip, struct rdc321x_gpio, chip);
  69
  70         if (value)
  71                 gpch->data_reg[reg] |= 1 << (gpio & 0x1f);
  72         else
  73                 gpch->data_reg[reg] &= ~(1 << (gpio & 0x1f));
  74
  75         pci_write_config_dword(gpch->sb_pdev,
  76                         reg ? gpch->reg2_data_base : gpch->reg1_data_base,
  77                         gpch->data_reg[reg]);
  78 }
  79
  80 /* set GPIO pin to value */
  81 static void rdc_gpio_set_value(struct gpio_chip *chip,
  82                                 unsigned gpio, int value)
  83 {
  84         struct rdc321x_gpio *gpch;
  85
  86         gpch = container_of(chip, struct rdc321x_gpio, chip);
  87         spin_lock(&gpch->lock);
  88         rdc_gpio_set_value_impl(chip, gpio, value);
  89         spin_unlock(&gpch->lock);
  90 }
  91
  92 static int rdc_gpio_config(struct gpio_chip *chip,
  93                                 unsigned gpio, int value)
  94 {
  95         struct rdc321x_gpio *gpch;
  96         int err;
  97         u32 reg;
  98
  99         gpch = container_of(chip, struct rdc321x_gpio, chip);
 100
 101         spin_lock(&gpch->lock);
 102         err = pci_read_config_dword(gpch->sb_pdev, gpio < 32 ?
 103                         gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, &reg);
 104         if (err)
 105                 goto unlock;
 106
 107         reg |= 1 << (gpio & 0x1f);
 108
 109         err = pci_write_config_dword(gpch->sb_pdev, gpio < 32 ?
 110                         gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, reg);
 111         if (err)
 112                 goto unlock;
 113
 114         rdc_gpio_set_value_impl(chip, gpio, value);
 115
 116 unlock:
 117         spin_unlock(&gpch->lock);
 118
 119         return err;
 120 }
 121
 122 /* configure GPIO pin as input */
 123 static int rdc_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
 124 {
 125         return rdc_gpio_config(chip, gpio, 1);
 126 }
 127
 128 /*
 129  * Cache the initial value of both GPIO data registers
 130  */
 131 static int rdc321x_gpio_probe(struct platform_device *pdev)
 132 {
 133         int err;
 134         struct resource *r;
 135         struct rdc321x_gpio *rdc321x_gpio_dev;
 136         struct rdc321x_gpio_pdata *pdata;
 137
 138         pdata = pdev->dev.platform_data;
 139         if (!pdata) {
 140                 dev_err(&pdev->dev, "no platform data supplied\n");
 141                 return -ENODEV;
 142         }
 143
 144         rdc321x_gpio_dev = kzalloc(sizeof(struct rdc321x_gpio), GFP_KERNEL);
 145         if (!rdc321x_gpio_dev) {
 146                 dev_err(&pdev->dev, "failed to allocate private data\n");
 147                 return -ENOMEM;
 148         }
 149
 150         r = platform_get_resource_byname(pdev, IORESOURCE_IO, "gpio-reg1");
 151         if (!r) {
 152                 dev_err(&pdev->dev, "failed to get gpio-reg1 resource\n");
 153                 err = -ENODEV;
 154                 goto out_free;
 155         }
 156
 157         spin_lock_init(&rdc321x_gpio_dev->lock);
 158         rdc321x_gpio_dev->sb_pdev = pdata->sb_pdev;
 159         rdc321x_gpio_dev->reg1_ctrl_base = r->start;
 160         rdc321x_gpio_dev->reg1_data_base = r->start + 0x4;
 161
 162         r = platform_get_resource_byname(pdev, IORESOURCE_IO, "gpio-reg2");
 163         if (!r) {
 164                 dev_err(&pdev->dev, "failed to get gpio-reg2 resource\n");
 165                 err = -ENODEV;
 166                 goto out_free;
 167         }
 168
 169         rdc321x_gpio_dev->reg2_ctrl_base = r->start;
 170         rdc321x_gpio_dev->reg2_data_base = r->start + 0x4;
 171
 172         rdc321x_gpio_dev->chip.label = "rdc321x-gpio";
 173         rdc321x_gpio_dev->chip.owner = THIS_MODULE;
 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_free;
 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_free;
 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_free:
 203         kfree(rdc321x_gpio_dev);
 204         return err;
 205 }
 206
 207 static int rdc321x_gpio_remove(struct platform_device *pdev)
 208 {
 209         int ret;
 210         struct rdc321x_gpio *rdc321x_gpio_dev = platform_get_drvdata(pdev);
 211
 212         ret = gpiochip_remove(&rdc321x_gpio_dev->chip);
 213         if (ret)
 214                 dev_err(&pdev->dev, "failed to unregister chip\n");
 215
 216         kfree(rdc321x_gpio_dev);
 217
 218         return ret;
 219 }
 220
 221 static struct platform_driver rdc321x_gpio_driver = {
 222         .driver.name    = "rdc321x-gpio",
 223         .driver.owner   = THIS_MODULE,
 224         .probe          = rdc321x_gpio_probe,
 225         .remove         = rdc321x_gpio_remove,
 226 };
 227
 228 module_platform_driver(rdc321x_gpio_driver);
 229
 230 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 231 MODULE_DESCRIPTION("RDC321x GPIO driver");
 232 MODULE_LICENSE("GPL");
 233 MODULE_ALIAS("platform:rdc321x-gpio");