drivers/char/pc8736x_gpio.c

   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
  27 MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
  28 MODULE_DESCRIPTION("NatSemi/Winbond PC-8736x GPIO Pin Driver");
  29 MODULE_LICENSE("GPL");
  30
  31 static int major;               /* default to dynamic major */
  32 module_param(major, int, 0);
  33 MODULE_PARM_DESC(major, "Major device number");
  34
  35 static DEFINE_MUTEX(pc8736x_gpio_config_lock);
  36 static unsigned pc8736x_gpio_base;
  37 static 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
  66 static unsigned char superio_cmd = 0;
  67 static unsigned char selected_device = 0xFF;    /* bogus start val */
  68
  69 /* GPIO port runtime access, functionality */
  70 static 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
  78 static struct platform_device *pdev;  /* use in dev_*() */
  79
  80 static inline void superio_outb(int addr, int val)
  81 {
  82         outb_p(addr, superio_cmd);
  83         outb_p(val, superio_cmd + 1);
  84 }
  85
  86 static inline int superio_inb(int addr)
  87 {
  88         outb_p(addr, superio_cmd);
  89         return inb_p(superio_cmd + 1);
  90 }
  91
  92 static 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
 110 static void device_select(unsigned devldn)
 111 {
 112         superio_outb(SIO_UNIT_SEL, devldn);
 113         selected_device = devldn;
 114 }
 115
 116 static 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
 124 static 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
 146 static 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
 152 static 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
 169 static 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
 196 static 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
 205 static void pc8736x_gpio_change(unsigned index)
 206 {
 207         pc8736x_gpio_set(index, !pc8736x_gpio_current(index));
 208 }
 209
 210 static 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
 220 static 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
 232 static 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
 240 static 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
 252 static struct cdev pc8736x_gpio_cdev;
 253
 254 static 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
 330 undo_request_region:
 331         release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);
 332 undo_platform_dev_add:
 333         platform_device_del(pdev);
 334 undo_platform_dev_alloc:
 335         platform_device_put(pdev);
 336
 337         return rc;
 338 }
 339
 340 static 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
 352 module_init(pc8736x_gpio_init);
 353 module_exit(pc8736x_gpio_cleanup);