linux/drivers/char/pc8736x_gpio.c
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   1/* linux/drivers/char/pc8736x_gpio.c
   2
   3   National Semiconductor PC8736x GPIO driver.  Allows a user space
   4   process to play with the GPIO pins.
   5
   6   Copyright (c) 2005,2006 Jim Cromie <jim.cromie@gmail.com>
   7
   8   adapted from linux/drivers/char/scx200_gpio.c
   9   Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>,
  10*/
  11
  12#include <linux/fs.h>
  13#include <linux/module.h>
  14#include <linux/errno.h>
  15#include <linux/kernel.h>
  16#include <linux/init.h>
  17#include <linux/cdev.h>
  18#include <linux/io.h>
  19#include <linux/ioport.h>
  20#include <linux/mutex.h>
  21#include <linux/nsc_gpio.h>
  22#include <linux/platform_device.h>
  23#include <asm/uaccess.h>
  24
  25#define DEVNAME "pc8736x_gpio"
  26
  27MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
  28MODULE_DESCRIPTION("NatSemi/Winbond PC-8736x GPIO Pin Driver");
  29MODULE_LICENSE("GPL");
  30
  31static int major;               /* default to dynamic major */
  32module_param(major, int, 0);
  33MODULE_PARM_DESC(major, "Major device number");
  34
  35static DEFINE_MUTEX(pc8736x_gpio_config_lock);
  36static unsigned pc8736x_gpio_base;
  37static u8 pc8736x_gpio_shadow[4];
  38
  39#define SIO_BASE1       0x2E    /* 1st command-reg to check */
  40#define SIO_BASE2       0x4E    /* alt command-reg to check */
  41
  42#define SIO_SID         0x20    /* SuperI/O ID Register */
  43#define SIO_SID_PC87365 0xe5    /* Expected value in ID Register for PC87365 */
  44#define SIO_SID_PC87366 0xe9    /* Expected value in ID Register for PC87366 */
  45
  46#define SIO_CF1         0x21    /* chip config, bit0 is chip enable */
  47
  48#define PC8736X_GPIO_RANGE      16 /* ioaddr range */
  49#define PC8736X_GPIO_CT         32 /* minors matching 4 8 bit ports */
  50
  51#define SIO_UNIT_SEL    0x7     /* unit select reg */
  52#define SIO_UNIT_ACT    0x30    /* unit enable */
  53#define SIO_GPIO_UNIT   0x7     /* unit number of GPIO */
  54#define SIO_VLM_UNIT    0x0D
  55#define SIO_TMS_UNIT    0x0E
  56
  57/* config-space addrs to read/write each unit's runtime addr */
  58#define SIO_BASE_HADDR          0x60
  59#define SIO_BASE_LADDR          0x61
  60
  61/* GPIO config-space pin-control addresses */
  62#define SIO_GPIO_PIN_SELECT     0xF0
  63#define SIO_GPIO_PIN_CONFIG     0xF1
  64#define SIO_GPIO_PIN_EVENT      0xF2
  65
  66static unsigned char superio_cmd = 0;
  67static unsigned char selected_device = 0xFF;    /* bogus start val */
  68
  69/* GPIO port runtime access, functionality */
  70static int port_offset[] = { 0, 4, 8, 10 };     /* non-uniform offsets ! */
  71/* static int event_capable[] = { 1, 1, 0, 0 };   ports 2,3 are hobbled */
  72
  73#define PORT_OUT        0
  74#define PORT_IN         1
  75#define PORT_EVT_EN     2
  76#define PORT_EVT_STST   3
  77
  78static struct platform_device *pdev;  /* use in dev_*() */
  79
  80static inline void superio_outb(int addr, int val)
  81{
  82        outb_p(addr, superio_cmd);
  83        outb_p(val, superio_cmd + 1);
  84}
  85
  86static inline int superio_inb(int addr)
  87{
  88        outb_p(addr, superio_cmd);
  89        return inb_p(superio_cmd + 1);
  90}
  91
  92static int pc8736x_superio_present(void)
  93{
  94        int id;
  95
  96        /* try the 2 possible values, read a hardware reg to verify */
  97        superio_cmd = SIO_BASE1;
  98        id = superio_inb(SIO_SID);
  99        if (id == SIO_SID_PC87365 || id == SIO_SID_PC87366)
 100                return superio_cmd;
 101
 102        superio_cmd = SIO_BASE2;
 103        id = superio_inb(SIO_SID);
 104        if (id == SIO_SID_PC87365 || id == SIO_SID_PC87366)
 105                return superio_cmd;
 106
 107        return 0;
 108}
 109
 110static void device_select(unsigned devldn)
 111{
 112        superio_outb(SIO_UNIT_SEL, devldn);
 113        selected_device = devldn;
 114}
 115
 116static void select_pin(unsigned iminor)
 117{
 118        /* select GPIO port/pin from device minor number */
 119        device_select(SIO_GPIO_UNIT);
 120        superio_outb(SIO_GPIO_PIN_SELECT,
 121                     ((iminor << 1) & 0xF0) | (iminor & 0x7));
 122}
 123
 124static inline u32 pc8736x_gpio_configure_fn(unsigned index, u32 mask, u32 bits,
 125                                            u32 func_slct)
 126{
 127        u32 config, new_config;
 128
 129        mutex_lock(&pc8736x_gpio_config_lock);
 130
 131        device_select(SIO_GPIO_UNIT);
 132        select_pin(index);
 133
 134        /* read current config value */
 135        config = superio_inb(func_slct);
 136
 137        /* set new config */
 138        new_config = (config & mask) | bits;
 139        superio_outb(func_slct, new_config);
 140
 141        mutex_unlock(&pc8736x_gpio_config_lock);
 142
 143        return config;
 144}
 145
 146static u32 pc8736x_gpio_configure(unsigned index, u32 mask, u32 bits)
 147{
 148        return pc8736x_gpio_configure_fn(index, mask, bits,
 149                                         SIO_GPIO_PIN_CONFIG);
 150}
 151
 152static int pc8736x_gpio_get(unsigned minor)
 153{
 154        int port, bit, val;
 155
 156        port = minor >> 3;
 157        bit = minor & 7;
 158        val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN);
 159        val >>= bit;
 160        val &= 1;
 161
 162        dev_dbg(&pdev->dev, "_gpio_get(%d from %x bit %d) == val %d\n",
 163                minor, pc8736x_gpio_base + port_offset[port] + PORT_IN, bit,
 164                val);
 165
 166        return val;
 167}
 168
 169static void pc8736x_gpio_set(unsigned minor, int val)
 170{
 171        int port, bit, curval;
 172
 173        minor &= 0x1f;
 174        port = minor >> 3;
 175        bit = minor & 7;
 176        curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT);
 177
 178        dev_dbg(&pdev->dev, "addr:%x cur:%x bit-pos:%d cur-bit:%x + new:%d -> bit-new:%d\n",
 179                pc8736x_gpio_base + port_offset[port] + PORT_OUT,
 180                curval, bit, (curval & ~(1 << bit)), val, (val << bit));
 181
 182        val = (curval & ~(1 << bit)) | (val << bit);
 183
 184        dev_dbg(&pdev->dev, "gpio_set(minor:%d port:%d bit:%d)"
 185                " %2x -> %2x\n", minor, port, bit, curval, val);
 186
 187        outb_p(val, pc8736x_gpio_base + port_offset[port] + PORT_OUT);
 188
 189        curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT);
 190        val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN);
 191
 192        dev_dbg(&pdev->dev, "wrote %x, read: %x\n", curval, val);
 193        pc8736x_gpio_shadow[port] = val;
 194}
 195
 196static int pc8736x_gpio_current(unsigned minor)
 197{
 198        int port, bit;
 199        minor &= 0x1f;
 200        port = minor >> 3;
 201        bit = minor & 7;
 202        return ((pc8736x_gpio_shadow[port] >> bit) & 0x01);
 203}
 204
 205static void pc8736x_gpio_change(unsigned index)
 206{
 207        pc8736x_gpio_set(index, !pc8736x_gpio_current(index));
 208}
 209
 210static struct nsc_gpio_ops pc8736x_gpio_ops = {
 211        .owner          = THIS_MODULE,
 212        .gpio_config    = pc8736x_gpio_configure,
 213        .gpio_dump      = nsc_gpio_dump,
 214        .gpio_get       = pc8736x_gpio_get,
 215        .gpio_set       = pc8736x_gpio_set,
 216        .gpio_change    = pc8736x_gpio_change,
 217        .gpio_current   = pc8736x_gpio_current
 218};
 219
 220static int pc8736x_gpio_open(struct inode *inode, struct file *file)
 221{
 222        unsigned m = iminor(inode);
 223        file->private_data = &pc8736x_gpio_ops;
 224
 225        dev_dbg(&pdev->dev, "open %d\n", m);
 226
 227        if (m >= PC8736X_GPIO_CT)
 228                return -EINVAL;
 229        return nonseekable_open(inode, file);
 230}
 231
 232static const struct file_operations pc8736x_gpio_fileops = {
 233        .owner  = THIS_MODULE,
 234        .open   = pc8736x_gpio_open,
 235        .write  = nsc_gpio_write,
 236        .read   = nsc_gpio_read,
 237        .llseek = no_llseek,
 238};
 239
 240static void __init pc8736x_init_shadow(void)
 241{
 242        int port;
 243
 244        /* read the current values driven on the GPIO signals */
 245        for (port = 0; port < 4; ++port)
 246                pc8736x_gpio_shadow[port]
 247                    = inb_p(pc8736x_gpio_base + port_offset[port]
 248                            + PORT_OUT);
 249
 250}
 251
 252static struct cdev pc8736x_gpio_cdev;
 253
 254static int __init pc8736x_gpio_init(void)
 255{
 256        int rc;
 257        dev_t devid;
 258
 259        pdev = platform_device_alloc(DEVNAME, 0);
 260        if (!pdev)
 261                return -ENOMEM;
 262
 263        rc = platform_device_add(pdev);
 264        if (rc) {
 265                rc = -ENODEV;
 266                goto undo_platform_dev_alloc;
 267        }
 268        dev_info(&pdev->dev, "NatSemi pc8736x GPIO Driver Initializing\n");
 269
 270        if (!pc8736x_superio_present()) {
 271                rc = -ENODEV;
 272                dev_err(&pdev->dev, "no device found\n");
 273                goto undo_platform_dev_add;
 274        }
 275        pc8736x_gpio_ops.dev = &pdev->dev;
 276
 277        /* Verify that chip and it's GPIO unit are both enabled.
 278           My BIOS does this, so I take minimum action here
 279         */
 280        rc = superio_inb(SIO_CF1);
 281        if (!(rc & 0x01)) {
 282                rc = -ENODEV;
 283                dev_err(&pdev->dev, "device not enabled\n");
 284                goto undo_platform_dev_add;
 285        }
 286        device_select(SIO_GPIO_UNIT);
 287        if (!superio_inb(SIO_UNIT_ACT)) {
 288                rc = -ENODEV;
 289                dev_err(&pdev->dev, "GPIO unit not enabled\n");
 290                goto undo_platform_dev_add;
 291        }
 292
 293        /* read the GPIO unit base addr that chip responds to */
 294        pc8736x_gpio_base = (superio_inb(SIO_BASE_HADDR) << 8
 295                             | superio_inb(SIO_BASE_LADDR));
 296
 297        if (!request_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE, DEVNAME)) {
 298                rc = -ENODEV;
 299                dev_err(&pdev->dev, "GPIO ioport %x busy\n",
 300                        pc8736x_gpio_base);
 301                goto undo_platform_dev_add;
 302        }
 303        dev_info(&pdev->dev, "GPIO ioport %x reserved\n", pc8736x_gpio_base);
 304
 305        if (major) {
 306                devid = MKDEV(major, 0);
 307                rc = register_chrdev_region(devid, PC8736X_GPIO_CT, DEVNAME);
 308        } else {
 309                rc = alloc_chrdev_region(&devid, 0, PC8736X_GPIO_CT, DEVNAME);
 310                major = MAJOR(devid);
 311        }
 312
 313        if (rc < 0) {
 314                dev_err(&pdev->dev, "register-chrdev failed: %d\n", rc);
 315                goto undo_request_region;
 316        }
 317        if (!major) {
 318                major = rc;
 319                dev_dbg(&pdev->dev, "got dynamic major %d\n", major);
 320        }
 321
 322        pc8736x_init_shadow();
 323
 324        /* ignore minor errs, and succeed */
 325        cdev_init(&pc8736x_gpio_cdev, &pc8736x_gpio_fileops);
 326        cdev_add(&pc8736x_gpio_cdev, devid, PC8736X_GPIO_CT);
 327
 328        return 0;
 329
 330undo_request_region:
 331        release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);
 332undo_platform_dev_add:
 333        platform_device_del(pdev);
 334undo_platform_dev_alloc:
 335        platform_device_put(pdev);
 336
 337        return rc;
 338}
 339
 340static void __exit pc8736x_gpio_cleanup(void)
 341{
 342        dev_dbg(&pdev->dev, "cleanup\n");
 343
 344        cdev_del(&pc8736x_gpio_cdev);
 345        unregister_chrdev_region(MKDEV(major,0), PC8736X_GPIO_CT);
 346        release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);
 347
 348        platform_device_del(pdev);
 349        platform_device_put(pdev);
 350}
 351
 352module_init(pc8736x_gpio_init);
 353module_exit(pc8736x_gpio_cleanup);
 354
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