drivers/i2c/busses/i2c-parport.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* ------------------------------------------------------------------------ *
   3  * i2c-parport.c I2C bus over parallel port                                 *
   4  * ------------------------------------------------------------------------ *
   5    Copyright (C) 2003-2011 Jean Delvare <jdelvare@suse.de>
   6
   7    Based on older i2c-philips-par.c driver
   8    Copyright (C) 1995-2000 Simon G. Vogl
   9    With some changes from:
  10    Frodo Looijaard <frodol@dds.nl>
  11    Kyösti Mälkki <kmalkki@cc.hut.fi>
  12
  13  * ------------------------------------------------------------------------ */
  14
  15 #define pr_fmt(fmt) "i2c-parport: " fmt
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/delay.h>
  21 #include <linux/parport.h>
  22 #include <linux/i2c.h>
  23 #include <linux/i2c-algo-bit.h>
  24 #include <linux/i2c-smbus.h>
  25 #include <linux/slab.h>
  26 #include <linux/list.h>
  27 #include <linux/mutex.h>
  28
  29 #define PORT_DATA       0
  30 #define PORT_STAT       1
  31 #define PORT_CTRL       2
  32
  33 struct lineop {
  34         u8 val;
  35         u8 port;
  36         u8 inverted;
  37 };
  38
  39 struct adapter_parm {
  40         struct lineop setsda;
  41         struct lineop setscl;
  42         struct lineop getsda;
  43         struct lineop getscl;
  44         struct lineop init;
  45         unsigned int smbus_alert:1;
  46 };
  47
  48 static const struct adapter_parm adapter_parm[] = {
  49         /* type 0: Philips adapter */
  50         {
  51                 .setsda = { 0x80, PORT_DATA, 1 },
  52                 .setscl = { 0x08, PORT_CTRL, 0 },
  53                 .getsda = { 0x80, PORT_STAT, 0 },
  54                 .getscl = { 0x08, PORT_STAT, 0 },
  55         },
  56         /* type 1: home brew teletext adapter */
  57         {
  58                 .setsda = { 0x02, PORT_DATA, 0 },
  59                 .setscl = { 0x01, PORT_DATA, 0 },
  60                 .getsda = { 0x80, PORT_STAT, 1 },
  61         },
  62         /* type 2: Velleman K8000 adapter */
  63         {
  64                 .setsda = { 0x02, PORT_CTRL, 1 },
  65                 .setscl = { 0x08, PORT_CTRL, 1 },
  66                 .getsda = { 0x10, PORT_STAT, 0 },
  67         },
  68         /* type 3: ELV adapter */
  69         {
  70                 .setsda = { 0x02, PORT_DATA, 1 },
  71                 .setscl = { 0x01, PORT_DATA, 1 },
  72                 .getsda = { 0x40, PORT_STAT, 1 },
  73                 .getscl = { 0x08, PORT_STAT, 1 },
  74         },
  75         /* type 4: ADM1032 evaluation board */
  76         {
  77                 .setsda = { 0x02, PORT_DATA, 1 },
  78                 .setscl = { 0x01, PORT_DATA, 1 },
  79                 .getsda = { 0x10, PORT_STAT, 1 },
  80                 .init   = { 0xf0, PORT_DATA, 0 },
  81                 .smbus_alert = 1,
  82         },
  83         /* type 5: ADM1025, ADM1030 and ADM1031 evaluation boards */
  84         {
  85                 .setsda = { 0x02, PORT_DATA, 1 },
  86                 .setscl = { 0x01, PORT_DATA, 1 },
  87                 .getsda = { 0x10, PORT_STAT, 1 },
  88         },
  89         /* type 6: Barco LPT->DVI (K5800236) adapter */
  90         {
  91                 .setsda = { 0x02, PORT_DATA, 1 },
  92                 .setscl = { 0x01, PORT_DATA, 1 },
  93                 .getsda = { 0x20, PORT_STAT, 0 },
  94                 .getscl = { 0x40, PORT_STAT, 0 },
  95                 .init   = { 0xfc, PORT_DATA, 0 },
  96         },
  97         /* type 7: One For All JP1 parallel port adapter */
  98         {
  99                 .setsda = { 0x01, PORT_DATA, 0 },
 100                 .setscl = { 0x02, PORT_DATA, 0 },
 101                 .getsda = { 0x80, PORT_STAT, 1 },
 102                 .init   = { 0x04, PORT_DATA, 1 },
 103         },
 104         /* type 8: VCT-jig */
 105         {
 106                 .setsda = { 0x04, PORT_DATA, 1 },
 107                 .setscl = { 0x01, PORT_DATA, 1 },
 108                 .getsda = { 0x40, PORT_STAT, 0 },
 109                 .getscl = { 0x80, PORT_STAT, 1 },
 110         },
 111 };
 112
 113 /* ----- Device list ------------------------------------------------------ */
 114
 115 struct i2c_par {
 116         struct pardevice *pdev;
 117         struct i2c_adapter adapter;
 118         struct i2c_algo_bit_data algo_data;
 119         struct i2c_smbus_alert_setup alert_data;
 120         struct i2c_client *ara;
 121         struct list_head node;
 122 };
 123
 124 static LIST_HEAD(adapter_list);
 125 static DEFINE_MUTEX(adapter_list_lock);
 126
 127 #define MAX_DEVICE 4
 128 static int parport[MAX_DEVICE] = {0, -1, -1, -1};
 129 module_param_array(parport, int, NULL, 0);
 130 MODULE_PARM_DESC(parport,
 131                  "List of parallel ports to bind to, by index.\n"
 132                  " At most " __stringify(MAX_DEVICE) " devices are supported.\n"
 133                  " Default is one device connected to parport0.\n"
 134 );
 135
 136 static int type = -1;
 137 module_param(type, int, 0);
 138 MODULE_PARM_DESC(type,
 139         "Type of adapter:\n"
 140         " 0 = Philips adapter\n"
 141         " 1 = home brew teletext adapter\n"
 142         " 2 = Velleman K8000 adapter\n"
 143         " 3 = ELV adapter\n"
 144         " 4 = ADM1032 evaluation board\n"
 145         " 5 = ADM1025, ADM1030 and ADM1031 evaluation boards\n"
 146         " 6 = Barco LPT->DVI (K5800236) adapter\n"
 147         " 7 = One For All JP1 parallel port adapter\n"
 148         " 8 = VCT-jig\n"
 149 );
 150
 151 /* ----- Low-level parallel port access ----------------------------------- */
 152
 153 static void port_write_data(struct parport *p, unsigned char d)
 154 {
 155         parport_write_data(p, d);
 156 }
 157
 158 static void port_write_control(struct parport *p, unsigned char d)
 159 {
 160         parport_write_control(p, d);
 161 }
 162
 163 static unsigned char port_read_data(struct parport *p)
 164 {
 165         return parport_read_data(p);
 166 }
 167
 168 static unsigned char port_read_status(struct parport *p)
 169 {
 170         return parport_read_status(p);
 171 }
 172
 173 static unsigned char port_read_control(struct parport *p)
 174 {
 175         return parport_read_control(p);
 176 }
 177
 178 static void (* const port_write[])(struct parport *, unsigned char) = {
 179         port_write_data,
 180         NULL,
 181         port_write_control,
 182 };
 183
 184 static unsigned char (* const port_read[])(struct parport *) = {
 185         port_read_data,
 186         port_read_status,
 187         port_read_control,
 188 };
 189
 190 /* ----- Unified line operation functions --------------------------------- */
 191
 192 static inline void line_set(struct parport *data, int state,
 193         const struct lineop *op)
 194 {
 195         u8 oldval = port_read[op->port](data);
 196
 197         /* Touch only the bit(s) needed */
 198         if ((op->inverted && !state) || (!op->inverted && state))
 199                 port_write[op->port](data, oldval | op->val);
 200         else
 201                 port_write[op->port](data, oldval & ~op->val);
 202 }
 203
 204 static inline int line_get(struct parport *data,
 205         const struct lineop *op)
 206 {
 207         u8 oldval = port_read[op->port](data);
 208
 209         return ((op->inverted && (oldval & op->val) != op->val)
 210             || (!op->inverted && (oldval & op->val) == op->val));
 211 }
 212
 213 /* ----- I2C algorithm call-back functions and structures ----------------- */
 214
 215 static void parport_setscl(void *data, int state)
 216 {
 217         line_set((struct parport *) data, state, &adapter_parm[type].setscl);
 218 }
 219
 220 static void parport_setsda(void *data, int state)
 221 {
 222         line_set((struct parport *) data, state, &adapter_parm[type].setsda);
 223 }
 224
 225 static int parport_getscl(void *data)
 226 {
 227         return line_get((struct parport *) data, &adapter_parm[type].getscl);
 228 }
 229
 230 static int parport_getsda(void *data)
 231 {
 232         return line_get((struct parport *) data, &adapter_parm[type].getsda);
 233 }
 234
 235 /* Encapsulate the functions above in the correct structure.
 236    Note that this is only a template, from which the real structures are
 237    copied. The attaching code will set getscl to NULL for adapters that
 238    cannot read SCL back, and will also make the data field point to
 239    the parallel port structure. */
 240 static const struct i2c_algo_bit_data parport_algo_data = {
 241         .setsda         = parport_setsda,
 242         .setscl         = parport_setscl,
 243         .getsda         = parport_getsda,
 244         .getscl         = parport_getscl,
 245         .udelay         = 10, /* ~50 kbps */
 246         .timeout        = HZ,
 247 };
 248
 249 /* ----- I2c and parallel port call-back functions and structures --------- */
 250
 251 static void i2c_parport_irq(void *data)
 252 {
 253         struct i2c_par *adapter = data;
 254         struct i2c_client *ara = adapter->ara;
 255
 256         if (ara) {
 257                 dev_dbg(&ara->dev, "SMBus alert received\n");
 258                 i2c_handle_smbus_alert(ara);
 259         } else
 260                 dev_dbg(&adapter->adapter.dev,
 261                         "SMBus alert received but no ARA client!\n");
 262 }
 263
 264 static void i2c_parport_attach(struct parport *port)
 265 {
 266         struct i2c_par *adapter;
 267         int i;
 268         struct pardev_cb i2c_parport_cb;
 269
 270         if (type < 0) {
 271                 pr_warn("adapter type unspecified\n");
 272                 return;
 273         }
 274
 275         if (type >= ARRAY_SIZE(adapter_parm)) {
 276                 pr_warn("invalid type (%d)\n", type);
 277                 return;
 278         }
 279
 280         for (i = 0; i < MAX_DEVICE; i++) {
 281                 if (parport[i] == -1)
 282                         continue;
 283                 if (port->number == parport[i])
 284                         break;
 285         }
 286         if (i == MAX_DEVICE) {
 287                 pr_debug("Not using parport%d.\n", port->number);
 288                 return;
 289         }
 290
 291         adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL);
 292         if (!adapter)
 293                 return;
 294         memset(&i2c_parport_cb, 0, sizeof(i2c_parport_cb));
 295         i2c_parport_cb.flags = PARPORT_FLAG_EXCL;
 296         i2c_parport_cb.irq_func = i2c_parport_irq;
 297         i2c_parport_cb.private = adapter;
 298
 299         pr_debug("attaching to %s\n", port->name);
 300         parport_disable_irq(port);
 301         adapter->pdev = parport_register_dev_model(port, "i2c-parport",
 302                                                    &i2c_parport_cb, i);
 303         if (!adapter->pdev) {
 304                 pr_err("Unable to register with parport\n");
 305                 goto err_free;
 306         }
 307
 308         /* Fill the rest of the structure */
 309         adapter->adapter.owner = THIS_MODULE;
 310         adapter->adapter.class = I2C_CLASS_HWMON;
 311         strscpy(adapter->adapter.name, "Parallel port adapter",
 312                 sizeof(adapter->adapter.name));
 313         adapter->algo_data = parport_algo_data;
 314         /* Slow down if we can't sense SCL */
 315         if (!adapter_parm[type].getscl.val) {
 316                 adapter->algo_data.getscl = NULL;
 317                 adapter->algo_data.udelay = 50; /* ~10 kbps */
 318         }
 319         adapter->algo_data.data = port;
 320         adapter->adapter.algo_data = &adapter->algo_data;
 321         adapter->adapter.dev.parent = port->physport->dev;
 322
 323         if (parport_claim_or_block(adapter->pdev) < 0) {
 324                 dev_err(&adapter->pdev->dev,
 325                         "Could not claim parallel port\n");
 326                 goto err_unregister;
 327         }
 328
 329         /* Reset hardware to a sane state (SCL and SDA high) */
 330         parport_setsda(port, 1);
 331         parport_setscl(port, 1);
 332         /* Other init if needed (power on...) */
 333         if (adapter_parm[type].init.val) {
 334                 line_set(port, 1, &adapter_parm[type].init);
 335                 /* Give powered devices some time to settle */
 336                 msleep(100);
 337         }
 338
 339         if (i2c_bit_add_bus(&adapter->adapter) < 0) {
 340                 dev_err(&adapter->pdev->dev, "Unable to register with I2C\n");
 341                 goto err_unregister;
 342         }
 343
 344         /* Setup SMBus alert if supported */
 345         if (adapter_parm[type].smbus_alert) {
 346                 struct i2c_client *ara;
 347
 348                 ara = i2c_new_smbus_alert_device(&adapter->adapter,
 349                                                  &adapter->alert_data);
 350                 if (!IS_ERR(ara)) {
 351                         adapter->ara = ara;
 352                         parport_enable_irq(port);
 353                 } else {
 354                         dev_warn(&adapter->pdev->dev,
 355                                  "Failed to register ARA client\n");
 356                 }
 357         }
 358
 359         /* Add the new adapter to the list */
 360         mutex_lock(&adapter_list_lock);
 361         list_add_tail(&adapter->node, &adapter_list);
 362         mutex_unlock(&adapter_list_lock);
 363         return;
 364
 365  err_unregister:
 366         parport_release(adapter->pdev);
 367         parport_unregister_device(adapter->pdev);
 368  err_free:
 369         kfree(adapter);
 370 }
 371
 372 static void i2c_parport_detach(struct parport *port)
 373 {
 374         struct i2c_par *adapter, *_n;
 375
 376         /* Walk the list */
 377         mutex_lock(&adapter_list_lock);
 378         list_for_each_entry_safe(adapter, _n, &adapter_list, node) {
 379                 if (adapter->pdev->port == port) {
 380                         if (adapter->ara) {
 381                                 parport_disable_irq(port);
 382                                 i2c_unregister_device(adapter->ara);
 383                         }
 384                         i2c_del_adapter(&adapter->adapter);
 385
 386                         /* Un-init if needed (power off...) */
 387                         if (adapter_parm[type].init.val)
 388                                 line_set(port, 0, &adapter_parm[type].init);
 389
 390                         parport_release(adapter->pdev);
 391                         parport_unregister_device(adapter->pdev);
 392                         list_del(&adapter->node);
 393                         kfree(adapter);
 394                 }
 395         }
 396         mutex_unlock(&adapter_list_lock);
 397 }
 398
 399 static struct parport_driver i2c_parport_driver = {
 400         .name = "i2c-parport",
 401         .match_port = i2c_parport_attach,
 402         .detach = i2c_parport_detach,
 403 };
 404 module_parport_driver(i2c_parport_driver);
 405
 406 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
 407 MODULE_DESCRIPTION("I2C bus over parallel port");
 408 MODULE_LICENSE("GPL");