LXR linux/drivers/gpio/vx855

   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
  49struct 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 */
  59static 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
  67static 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
  75static 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
  83static 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
  97static 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
 122static 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
 147static 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
 175static 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
 190static 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
 203static 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 */
 221static __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
 276out_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
 286static 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
 308static 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
 317static int vx855gpio_init(void)
 318{
 319        return platform_driver_register(&vx855gpio_driver);
 320}
 321module_init(vx855gpio_init);
 322
 323static void vx855gpio_exit(void)
 324{
 325        platform_driver_unregister(&vx855gpio_driver);
 326}
 327module_exit(vx855gpio_exit);
 328
 329MODULE_LICENSE("GPL");
 330MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
 331MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset");
 332MODULE_ALIAS("platform:vx855_gpio");
 333