2 * IEEE 1284.3 Parallel port daisy chain and multiplexor code
4 * Copyright (C) 1999, 2000 Tim Waugh <tim@cyberelk.demon.co.uk>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
11 * ??-12-1998: Initial implementation.
12 * 31-01-1999: Make port-cloning transparent.
13 * 13-02-1999: Move DeviceID technique from parport_probe.
14 * 13-03-1999: Get DeviceID from non-IEEE 1284.3 devices too.
15 * 22-02-2000: Count devices that are actually detected.
17 * Any part of this program may be used in documents licensed under
18 * the GNU Free Documentation License, Version 1.1 or any later version
19 * published by the Free Software Foundation.
22 #include <linux/module.h>
23 #include <linux/parport.h>
24 #include <linux/delay.h>
25 #include <linux/slab.h>
26 #include <linux/sched/signal.h>
28 #include <asm/current.h>
29 #include <linux/uaccess.h>
34 #define DPRINTK(stuff...) printk(stuff)
36 #define DPRINTK(stuff...)
39 static struct daisydev {
40 struct daisydev *next;
45 static DEFINE_SPINLOCK(topology_lock);
49 /* Forward-declaration of lower-level functions. */
50 static int mux_present(struct parport *port);
51 static int num_mux_ports(struct parport *port);
52 static int select_port(struct parport *port);
53 static int assign_addrs(struct parport *port);
55 /* Add a device to the discovered topology. */
56 static void add_dev(int devnum, struct parport *port, int daisy)
58 struct daisydev *newdev, **p;
59 newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL);
62 newdev->daisy = daisy;
63 newdev->devnum = devnum;
64 spin_lock(&topology_lock);
65 for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next)
69 spin_unlock(&topology_lock);
73 /* Clone a parport (actually, make an alias). */
74 static struct parport *clone_parport(struct parport *real, int muxport)
76 struct parport *extra = parport_register_port(real->base,
81 extra->portnum = real->portnum;
82 extra->physport = real;
83 extra->muxport = muxport;
84 real->slaves[muxport-1] = extra;
90 /* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.
91 * Return value is number of devices actually detected. */
92 int parport_daisy_init(struct parport *port)
96 static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" };
102 /* Because this is called before any other devices exist,
103 * we don't have to claim exclusive access. */
105 /* If mux present on normal port, need to create new
106 * parports for each extra port. */
107 if (port->muxport < 0 && mux_present(port) &&
108 /* don't be fooled: a mux must have 2 or 4 ports. */
109 ((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) {
110 /* Leave original as port zero. */
113 "%s: 1st (default) port of %d-way multiplexor\n",
114 port->name, num_ports);
115 for (i = 1; i < num_ports; i++) {
116 /* Clone the port. */
117 struct parport *extra = clone_parport(port, i);
119 if (signal_pending(current))
127 "%s: %d%s port of %d-way multiplexor on %s\n",
128 extra->name, i + 1, th[i + 1], num_ports,
131 /* Analyse that port too. We won't recurse
132 forever because of the 'port->muxport < 0'
134 parport_daisy_init(extra);
138 if (port->muxport >= 0)
141 parport_daisy_deselect_all(port);
142 detected += assign_addrs(port);
144 /* Count the potential legacy device at the end. */
145 add_dev(numdevs++, port, -1);
147 /* Find out the legacy device's IEEE 1284 device ID. */
148 deviceid = kmalloc(1024, GFP_KERNEL);
150 if (parport_device_id(numdevs - 1, deviceid, 1024) > 2)
156 if (!detected && !last_try) {
157 /* No devices were detected. Perhaps they are in some
158 funny state; let's try to reset them and see if
160 parport_daisy_fini(port);
161 parport_write_control(port, PARPORT_CONTROL_SELECT);
163 parport_write_control(port,
164 PARPORT_CONTROL_SELECT |
165 PARPORT_CONTROL_INIT);
174 /* Forget about devices on a physical port. */
175 void parport_daisy_fini(struct parport *port)
179 spin_lock(&topology_lock);
182 struct daisydev *dev = *p;
183 if (dev->port != port) {
191 /* Gaps in the numbering could be handled better. How should
192 someone enumerate through all IEEE1284.3 devices in the
194 if (!topology) numdevs = 0;
195 spin_unlock(&topology_lock);
200 * parport_open - find a device by canonical device number
201 * @devnum: canonical device number
202 * @name: name to associate with the device
204 * This function is similar to parport_register_device(), except
205 * that it locates a device by its number rather than by the port
208 * All parameters except for @devnum are the same as for
209 * parport_register_device(). The return value is the same as
210 * for parport_register_device().
213 struct pardevice *parport_open(int devnum, const char *name)
215 struct daisydev *p = topology;
216 struct pardev_cb par_cb;
217 struct parport *port;
218 struct pardevice *dev;
221 memset(&par_cb, 0, sizeof(par_cb));
222 spin_lock(&topology_lock);
223 while (p && p->devnum != devnum)
227 spin_unlock(&topology_lock);
232 port = parport_get_port(p->port);
233 spin_unlock(&topology_lock);
235 dev = parport_register_dev_model(port, name, &par_cb, devnum);
236 parport_put_port(port);
242 /* Check that there really is a device to select. */
245 parport_claim_or_block(dev);
246 selected = port->daisy;
247 parport_release(dev);
249 if (selected != daisy) {
250 /* No corresponding device. */
251 parport_unregister_device(dev);
260 * parport_close - close a device opened with parport_open()
261 * @dev: device to close
263 * This is to parport_open() as parport_unregister_device() is to
264 * parport_register_device().
267 void parport_close(struct pardevice *dev)
269 parport_unregister_device(dev);
272 /* Send a daisy-chain-style CPP command packet. */
273 static int cpp_daisy(struct parport *port, int cmd)
277 parport_data_forward(port);
278 parport_write_data(port, 0xaa); udelay(2);
279 parport_write_data(port, 0x55); udelay(2);
280 parport_write_data(port, 0x00); udelay(2);
281 parport_write_data(port, 0xff); udelay(2);
282 s = parport_read_status(port) & (PARPORT_STATUS_BUSY
283 | PARPORT_STATUS_PAPEROUT
284 | PARPORT_STATUS_SELECT
285 | PARPORT_STATUS_ERROR);
286 if (s != (PARPORT_STATUS_BUSY
287 | PARPORT_STATUS_PAPEROUT
288 | PARPORT_STATUS_SELECT
289 | PARPORT_STATUS_ERROR)) {
290 DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff(%02x)\n",
295 parport_write_data(port, 0x87); udelay(2);
296 s = parport_read_status(port) & (PARPORT_STATUS_BUSY
297 | PARPORT_STATUS_PAPEROUT
298 | PARPORT_STATUS_SELECT
299 | PARPORT_STATUS_ERROR);
300 if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
301 DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff87(%02x)\n",
306 parport_write_data(port, 0x78); udelay(2);
307 parport_write_data(port, cmd); udelay(2);
308 parport_frob_control(port,
309 PARPORT_CONTROL_STROBE,
310 PARPORT_CONTROL_STROBE);
312 s = parport_read_status(port);
313 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
315 parport_write_data(port, 0xff); udelay(2);
320 /* Send a mux-style CPP command packet. */
321 static int cpp_mux(struct parport *port, int cmd)
326 parport_data_forward(port);
327 parport_write_data(port, 0xaa); udelay(2);
328 parport_write_data(port, 0x55); udelay(2);
329 parport_write_data(port, 0xf0); udelay(2);
330 parport_write_data(port, 0x0f); udelay(2);
331 parport_write_data(port, 0x52); udelay(2);
332 parport_write_data(port, 0xad); udelay(2);
333 parport_write_data(port, cmd); udelay(2);
335 s = parport_read_status(port);
336 if (!(s & PARPORT_STATUS_ACK)) {
337 DPRINTK(KERN_DEBUG "%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",
342 rc = (((s & PARPORT_STATUS_SELECT ? 1 : 0) << 0) |
343 ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |
344 ((s & PARPORT_STATUS_BUSY ? 0 : 1) << 2) |
345 ((s & PARPORT_STATUS_ERROR ? 0 : 1) << 3));
350 void parport_daisy_deselect_all(struct parport *port)
352 cpp_daisy(port, 0x30);
355 int parport_daisy_select(struct parport *port, int daisy, int mode)
359 // For these modes we should switch to EPP mode:
360 case IEEE1284_MODE_EPP:
361 case IEEE1284_MODE_EPPSL:
362 case IEEE1284_MODE_EPPSWE:
363 return !(cpp_daisy(port, 0x20 + daisy) &
364 PARPORT_STATUS_ERROR);
366 // For these modes we should switch to ECP mode:
367 case IEEE1284_MODE_ECP:
368 case IEEE1284_MODE_ECPRLE:
369 case IEEE1284_MODE_ECPSWE:
370 return !(cpp_daisy(port, 0xd0 + daisy) &
371 PARPORT_STATUS_ERROR);
373 // Nothing was told for BECP in Daisy chain specification.
374 // May be it's wise to use ECP?
375 case IEEE1284_MODE_BECP:
376 // Others use compat mode
377 case IEEE1284_MODE_NIBBLE:
378 case IEEE1284_MODE_BYTE:
379 case IEEE1284_MODE_COMPAT:
381 return !(cpp_daisy(port, 0xe0 + daisy) &
382 PARPORT_STATUS_ERROR);
386 static int mux_present(struct parport *port)
388 return cpp_mux(port, 0x51) == 3;
391 static int num_mux_ports(struct parport *port)
393 return cpp_mux(port, 0x58);
396 static int select_port(struct parport *port)
398 int muxport = port->muxport;
399 return cpp_mux(port, 0x60 + muxport) == muxport;
402 static int assign_addrs(struct parport *port)
406 int thisdev = numdevs;
410 parport_data_forward(port);
411 parport_write_data(port, 0xaa); udelay(2);
412 parport_write_data(port, 0x55); udelay(2);
413 parport_write_data(port, 0x00); udelay(2);
414 parport_write_data(port, 0xff); udelay(2);
415 s = parport_read_status(port) & (PARPORT_STATUS_BUSY
416 | PARPORT_STATUS_PAPEROUT
417 | PARPORT_STATUS_SELECT
418 | PARPORT_STATUS_ERROR);
419 if (s != (PARPORT_STATUS_BUSY
420 | PARPORT_STATUS_PAPEROUT
421 | PARPORT_STATUS_SELECT
422 | PARPORT_STATUS_ERROR)) {
423 DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff(%02x)\n",
428 parport_write_data(port, 0x87); udelay(2);
429 s = parport_read_status(port) & (PARPORT_STATUS_BUSY
430 | PARPORT_STATUS_PAPEROUT
431 | PARPORT_STATUS_SELECT
432 | PARPORT_STATUS_ERROR);
433 if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
434 DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff87(%02x)\n",
439 parport_write_data(port, 0x78); udelay(2);
440 s = parport_read_status(port);
443 (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
444 == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
447 parport_write_data(port, daisy);
449 parport_frob_control(port,
450 PARPORT_CONTROL_STROBE,
451 PARPORT_CONTROL_STROBE);
453 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
456 add_dev(numdevs++, port, daisy);
458 /* See if this device thought it was the last in the
460 if (!(s & PARPORT_STATUS_BUSY))
463 /* We are seeing pass through status now. We see
464 last_dev from next device or if last_dev does not
465 work status lines from some non-daisy chain
467 s = parport_read_status(port);
470 parport_write_data(port, 0xff); udelay(2);
471 detected = numdevs - thisdev;
472 DPRINTK(KERN_DEBUG "%s: Found %d daisy-chained devices\n", port->name,
475 /* Ask the new devices to introduce themselves. */
476 deviceid = kmalloc(1024, GFP_KERNEL);
477 if (!deviceid) return 0;
479 for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)
480 parport_device_id(thisdev, deviceid, 1024);
486 static int daisy_drv_probe(struct pardevice *par_dev)
488 struct device_driver *drv = par_dev->dev.driver;
490 if (strcmp(drv->name, "daisy_drv"))
492 if (strcmp(par_dev->name, daisy_dev_name))
498 static struct parport_driver daisy_driver = {
500 .probe = daisy_drv_probe,
504 int daisy_drv_init(void)
506 return parport_register_driver(&daisy_driver);
509 void daisy_drv_exit(void)
511 parport_unregister_driver(&daisy_driver);