drivers/gpio/vx855_gpio.c

   1 /*
   2  * Linux GPIOlib driver for the VIA VX855 integrated southbridge GPIO
   3  *
   4  * Copyright (C) 2009 VIA Technologies, Inc.
   5  * Copyright (C) 2010 One Laptop per Child
   6  * Author: Harald Welte <HaraldWelte@viatech.com>
   7  * All rights reserved.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation; either version 2 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  22  * MA 02111-1307 USA
  23  *
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/module.h>
  28 #include <linux/gpio.h>
  29 #include <linux/device.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/pci.h>
  32 #include <linux/io.h>
  33
  34 #define MODULE_NAME "vx855_gpio"
  35
  36 /* The VX855 south bridge has the following GPIO pins:
  37  *      GPI 0...13      General Purpose Input
  38  *      GPO 0...12      General Purpose Output
  39  *      GPIO 0...14     General Purpose I/O (Open-Drain)
  40  */
  41
  42 #define NR_VX855_GPI    14
  43 #define NR_VX855_GPO    13
  44 #define NR_VX855_GPIO   15
  45
  46 #define NR_VX855_GPInO  (NR_VX855_GPI + NR_VX855_GPO)
  47 #define NR_VX855_GP     (NR_VX855_GPI + NR_VX855_GPO + NR_VX855_GPIO)
  48
  49 struct vx855_gpio {
  50         struct gpio_chip gpio;
  51         spinlock_t lock;
  52         u32 io_gpi;
  53         u32 io_gpo;
  54         bool gpi_reserved;
  55         bool gpo_reserved;
  56 };
  57
  58 /* resolve a GPIx into the corresponding bit position */
  59 static inline u_int32_t gpi_i_bit(int i)
  60 {
  61         if (i < 10)
  62                 return 1 << i;
  63         else
  64                 return 1 << (i + 14);
  65 }
  66
  67 static inline u_int32_t gpo_o_bit(int i)
  68 {
  69         if (i < 11)
  70                 return 1 << i;
  71         else
  72                 return 1 << (i + 14);
  73 }
  74
  75 static inline u_int32_t gpio_i_bit(int i)
  76 {
  77         if (i < 14)
  78                 return 1 << (i + 10);
  79         else
  80                 return 1 << (i + 14);
  81 }
  82
  83 static inline u_int32_t gpio_o_bit(int i)
  84 {
  85         if (i < 14)
  86                 return 1 << (i + 11);
  87         else
  88                 return 1 << (i + 13);
  89 }
  90
  91 /* Mapping betwee numeric GPIO ID and the actual GPIO hardware numbering:
  92  * 0..13        GPI 0..13
  93  * 14..26       GPO 0..12
  94  * 27..41       GPIO 0..14
  95  */
  96
  97 static int vx855gpio_direction_input(struct gpio_chip *gpio,
  98                                      unsigned int nr)
  99 {
 100         struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
 101         unsigned long flags;
 102         u_int32_t reg_out;
 103
 104         /* Real GPI bits are always in input direction */
 105         if (nr < NR_VX855_GPI)
 106                 return 0;
 107
 108         /* Real GPO bits cannot be put in output direction */
 109         if (nr < NR_VX855_GPInO)
 110                 return -EINVAL;
 111
 112         /* Open Drain GPIO have to be set to one */
 113         spin_lock_irqsave(&vg->lock, flags);
 114         reg_out = inl(vg->io_gpo);
 115         reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);
 116         outl(reg_out, vg->io_gpo);
 117         spin_unlock_irqrestore(&vg->lock, flags);
 118
 119         return 0;
 120 }
 121
 122 static int vx855gpio_get(struct gpio_chip *gpio, unsigned int nr)
 123 {
 124         struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
 125         u_int32_t reg_in;
 126         int ret = 0;
 127
 128         if (nr < NR_VX855_GPI) {
 129                 reg_in = inl(vg->io_gpi);
 130                 if (reg_in & gpi_i_bit(nr))
 131                         ret = 1;
 132         } else if (nr < NR_VX855_GPInO) {
 133                 /* GPO don't have an input bit, we need to read it
 134                  * back from the output register */
 135                 reg_in = inl(vg->io_gpo);
 136                 if (reg_in & gpo_o_bit(nr - NR_VX855_GPI))
 137                         ret = 1;
 138         } else {
 139                 reg_in = inl(vg->io_gpi);
 140                 if (reg_in & gpio_i_bit(nr - NR_VX855_GPInO))
 141                         ret = 1;
 142         }
 143
 144         return ret;
 145 }
 146
 147 static void vx855gpio_set(struct gpio_chip *gpio, unsigned int nr,
 148                           int val)
 149 {
 150         struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
 151         unsigned long flags;
 152         u_int32_t reg_out;
 153
 154         /* True GPI cannot be switched to output mode */
 155         if (nr < NR_VX855_GPI)
 156                 return;
 157
 158         spin_lock_irqsave(&vg->lock, flags);
 159         reg_out = inl(vg->io_gpo);
 160         if (nr < NR_VX855_GPInO) {
 161                 if (val)
 162                         reg_out |= gpo_o_bit(nr - NR_VX855_GPI);
 163                 else
 164                         reg_out &= ~gpo_o_bit(nr - NR_VX855_GPI);
 165         } else {
 166                 if (val)
 167                         reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);
 168                 else
 169                         reg_out &= ~gpio_o_bit(nr - NR_VX855_GPInO);
 170         }
 171         outl(reg_out, vg->io_gpo);
 172         spin_unlock_irqrestore(&vg->lock, flags);
 173 }
 174
 175 static int vx855gpio_direction_output(struct gpio_chip *gpio,
 176                                       unsigned int nr, int val)
 177 {
 178         /* True GPI cannot be switched to output mode */
 179         if (nr < NR_VX855_GPI)
 180                 return -EINVAL;
 181
 182         /* True GPO don't need to be switched to output mode,
 183          * and GPIO are open-drain, i.e. also need no switching,
 184          * so all we do is set the level */
 185         vx855gpio_set(gpio, nr, val);
 186
 187         return 0;
 188 }
 189
 190 static const char *vx855gpio_names[NR_VX855_GP] = {
 191         "VX855_GPI0", "VX855_GPI1", "VX855_GPI2", "VX855_GPI3", "VX855_GPI4",
 192         "VX855_GPI5", "VX855_GPI6", "VX855_GPI7", "VX855_GPI8", "VX855_GPI9",
 193         "VX855_GPI10", "VX855_GPI11", "VX855_GPI12", "VX855_GPI13",
 194         "VX855_GPO0", "VX855_GPO1", "VX855_GPO2", "VX855_GPO3", "VX855_GPO4",
 195         "VX855_GPO5", "VX855_GPO6", "VX855_GPO7", "VX855_GPO8", "VX855_GPO9",
 196         "VX855_GPO10", "VX855_GPO11", "VX855_GPO12",
 197         "VX855_GPIO0", "VX855_GPIO1", "VX855_GPIO2", "VX855_GPIO3",
 198         "VX855_GPIO4", "VX855_GPIO5", "VX855_GPIO6", "VX855_GPIO7",
 199         "VX855_GPIO8", "VX855_GPIO9", "VX855_GPIO10", "VX855_GPIO11",
 200         "VX855_GPIO12", "VX855_GPIO13", "VX855_GPIO14"
 201 };
 202
 203 static void vx855gpio_gpio_setup(struct vx855_gpio *vg)
 204 {
 205         struct gpio_chip *c = &vg->gpio;
 206
 207         c->label = "VX855 South Bridge";
 208         c->owner = THIS_MODULE;
 209         c->direction_input = vx855gpio_direction_input;
 210         c->direction_output = vx855gpio_direction_output;
 211         c->get = vx855gpio_get;
 212         c->set = vx855gpio_set;
 213         c->dbg_show = NULL;
 214         c->base = 0;
 215         c->ngpio = NR_VX855_GP;
 216         c->can_sleep = 0;
 217         c->names = vx855gpio_names;
 218 }
 219
 220 /* This platform device is ordinarily registered by the vx855 mfd driver */
 221 static __devinit int vx855gpio_probe(struct platform_device *pdev)
 222 {
 223         struct resource *res_gpi;
 224         struct resource *res_gpo;
 225         struct vx855_gpio *vg;
 226         int ret;
 227
 228         res_gpi = platform_get_resource(pdev, IORESOURCE_IO, 0);
 229         res_gpo = platform_get_resource(pdev, IORESOURCE_IO, 1);
 230         if (!res_gpi || !res_gpo)
 231                 return -EBUSY;
 232
 233         vg = kzalloc(sizeof(*vg), GFP_KERNEL);
 234         if (!vg)
 235                 return -ENOMEM;
 236
 237         platform_set_drvdata(pdev, vg);
 238
 239         dev_info(&pdev->dev, "found VX855 GPIO controller\n");
 240         vg->io_gpi = res_gpi->start;
 241         vg->io_gpo = res_gpo->start;
 242         spin_lock_init(&vg->lock);
 243
 244         /*
 245          * A single byte is used to control various GPIO ports on the VX855,
 246          * and in the case of the OLPC XO-1.5, some of those ports are used
 247          * for switches that are interpreted and exposed through ACPI. ACPI
 248          * will have reserved the region, so our own reservation will not
 249          * succeed. Ignore and continue.
 250          */
 251
 252         if (!request_region(res_gpi->start, resource_size(res_gpi),
 253                         MODULE_NAME "_gpi"))
 254                 dev_warn(&pdev->dev,
 255                         "GPI I/O resource busy, probably claimed by ACPI\n");
 256         else
 257                 vg->gpi_reserved = true;
 258
 259         if (!request_region(res_gpo->start, resource_size(res_gpo),
 260                         MODULE_NAME "_gpo"))
 261                 dev_warn(&pdev->dev,
 262                         "GPO I/O resource busy, probably claimed by ACPI\n");
 263         else
 264                 vg->gpo_reserved = true;
 265
 266         vx855gpio_gpio_setup(vg);
 267
 268         ret = gpiochip_add(&vg->gpio);
 269         if (ret) {
 270                 dev_err(&pdev->dev, "failed to register GPIOs\n");
 271                 goto out_release;
 272         }
 273
 274         return 0;
 275
 276 out_release:
 277         if (vg->gpi_reserved)
 278                 release_region(res_gpi->start, resource_size(res_gpi));
 279         if (vg->gpo_reserved)
 280                 release_region(res_gpi->start, resource_size(res_gpo));
 281         platform_set_drvdata(pdev, NULL);
 282         kfree(vg);
 283         return ret;
 284 }
 285
 286 static int __devexit vx855gpio_remove(struct platform_device *pdev)
 287 {
 288         struct vx855_gpio *vg = platform_get_drvdata(pdev);
 289         struct resource *res;
 290
 291         if (gpiochip_remove(&vg->gpio))
 292                 dev_err(&pdev->dev, "unable to remove gpio_chip?\n");
 293
 294         if (vg->gpi_reserved) {
 295                 res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 296                 release_region(res->start, resource_size(res));
 297         }
 298         if (vg->gpo_reserved) {
 299                 res = platform_get_resource(pdev, IORESOURCE_IO, 1);
 300                 release_region(res->start, resource_size(res));
 301         }
 302
 303         platform_set_drvdata(pdev, NULL);
 304         kfree(vg);
 305         return 0;
 306 }
 307
 308 static struct platform_driver vx855gpio_driver = {
 309         .driver = {
 310                 .name   = MODULE_NAME,
 311                 .owner  = THIS_MODULE,
 312         },
 313         .probe          = vx855gpio_probe,
 314         .remove         = __devexit_p(vx855gpio_remove),
 315 };
 316
 317 static int vx855gpio_init(void)
 318 {
 319         return platform_driver_register(&vx855gpio_driver);
 320 }
 321 module_init(vx855gpio_init);
 322
 323 static void vx855gpio_exit(void)
 324 {
 325         platform_driver_unregister(&vx855gpio_driver);
 326 }
 327 module_exit(vx855gpio_exit);
 328
 329 MODULE_LICENSE("GPL");
 330 MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
 331 MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset");
 332 MODULE_ALIAS("platform:vx855_gpio");