Commit | Line | Data |
---|---|---|
25a010c8 CN |
1 | |
2 | Linux USB Printer Gadget Driver | |
3 | 06/04/2007 | |
4 | ||
5 | Copyright (C) 2007 Craig W. Nadler <craig@nadler.us> | |
6 | ||
7 | ||
8 | ||
9 | GENERAL | |
10 | ======= | |
11 | ||
12 | This driver may be used if you are writing printer firmware using Linux as | |
13 | the embedded OS. This driver has nothing to do with using a printer with | |
14 | your Linux host system. | |
15 | ||
16 | You will need a USB device controller and a Linux driver for it that accepts | |
17 | a gadget / "device class" driver using the Linux USB Gadget API. After the | |
18 | USB device controller driver is loaded then load the printer gadget driver. | |
19 | This will present a printer interface to the USB Host that your USB Device | |
20 | port is connected to. | |
21 | ||
22 | This driver is structured for printer firmware that runs in user mode. The | |
23 | user mode printer firmware will read and write data from the kernel mode | |
24 | printer gadget driver using a device file. The printer returns a printer status | |
25 | byte when the USB HOST sends a device request to get the printer status. The | |
26 | user space firmware can read or write this status byte using a device file | |
27 | /dev/g_printer . Both blocking and non-blocking read/write calls are supported. | |
28 | ||
29 | ||
30 | ||
31 | ||
32 | HOWTO USE THIS DRIVER | |
33 | ===================== | |
34 | ||
35 | To load the USB device controller driver and the printer gadget driver. The | |
36 | following example uses the Netchip 2280 USB device controller driver: | |
37 | ||
38 | modprobe net2280 | |
39 | modprobe g_printer | |
40 | ||
41 | ||
42 | The follow command line parameter can be used when loading the printer gadget | |
43 | (ex: modprobe g_printer idVendor=0x0525 idProduct=0xa4a8 ): | |
44 | ||
45 | idVendor - This is the Vendor ID used in the device descriptor. The default is | |
46 | the Netchip vendor id 0x0525. YOU MUST CHANGE TO YOUR OWN VENDOR ID | |
47 | BEFORE RELEASING A PRODUCT. If you plan to release a product and don't | |
48 | already have a Vendor ID please see www.usb.org for details on how to | |
49 | get one. | |
50 | ||
51 | idProduct - This is the Product ID used in the device descriptor. The default | |
52 | is 0xa4a8, you should change this to an ID that's not used by any of | |
53 | your other USB products if you have any. It would be a good idea to | |
54 | start numbering your products starting with say 0x0001. | |
55 | ||
56 | bcdDevice - This is the version number of your product. It would be a good idea | |
57 | to put your firmware version here. | |
58 | ||
59 | iManufacturer - A string containing the name of the Vendor. | |
60 | ||
61 | iProduct - A string containing the Product Name. | |
62 | ||
63 | iSerialNum - A string containing the Serial Number. This should be changed for | |
64 | each unit of your product. | |
65 | ||
66 | iPNPstring - The PNP ID string used for this printer. You will want to set | |
67 | either on the command line or hard code the PNP ID string used for | |
68 | your printer product. | |
69 | ||
70 | qlen - The number of 8k buffers to use per endpoint. The default is 10, you | |
71 | should tune this for your product. You may also want to tune the | |
72 | size of each buffer for your product. | |
73 | ||
74 | ||
75 | ||
76 | ||
77 | USING THE EXAMPLE CODE | |
78 | ====================== | |
79 | ||
80 | This example code talks to stdout, instead of a print engine. | |
81 | ||
82 | To compile the test code below: | |
83 | ||
84 | 1) save it to a file called prn_example.c | |
85 | 2) compile the code with the follow command: | |
86 | gcc prn_example.c -o prn_example | |
87 | ||
88 | ||
89 | ||
90 | To read printer data from the host to stdout: | |
91 | ||
92 | # prn_example -read_data | |
93 | ||
94 | ||
95 | To write printer data from a file (data_file) to the host: | |
96 | ||
97 | # cat data_file | prn_example -write_data | |
98 | ||
99 | ||
100 | To get the current printer status for the gadget driver: | |
101 | ||
102 | # prn_example -get_status | |
103 | ||
104 | Printer status is: | |
105 | Printer is NOT Selected | |
106 | Paper is Out | |
107 | Printer OK | |
108 | ||
109 | ||
110 | To set printer to Selected/On-line: | |
111 | ||
112 | # prn_example -selected | |
113 | ||
114 | ||
115 | To set printer to Not Selected/Off-line: | |
116 | ||
117 | # prn_example -not_selected | |
118 | ||
119 | ||
120 | To set paper status to paper out: | |
121 | ||
122 | # prn_example -paper_out | |
123 | ||
124 | ||
125 | To set paper status to paper loaded: | |
126 | ||
127 | # prn_example -paper_loaded | |
128 | ||
129 | ||
130 | To set error status to printer OK: | |
131 | ||
132 | # prn_example -no_error | |
133 | ||
134 | ||
135 | To set error status to ERROR: | |
136 | ||
137 | # prn_example -error | |
138 | ||
139 | ||
140 | ||
141 | ||
142 | EXAMPLE CODE | |
143 | ============ | |
144 | ||
145 | ||
146 | #include <stdio.h> | |
147 | #include <stdlib.h> | |
148 | #include <fcntl.h> | |
149 | #include <linux/poll.h> | |
150 | #include <sys/ioctl.h> | |
151 | #include <linux/usb/g_printer.h> | |
152 | ||
153 | #define PRINTER_FILE "/dev/g_printer" | |
154 | #define BUF_SIZE 512 | |
155 | ||
156 | ||
157 | /* | |
158 | * 'usage()' - Show program usage. | |
159 | */ | |
160 | ||
161 | static void | |
162 | usage(const char *option) /* I - Option string or NULL */ | |
163 | { | |
164 | if (option) { | |
165 | fprintf(stderr,"prn_example: Unknown option \"%s\"!\n", | |
166 | option); | |
167 | } | |
168 | ||
169 | fputs("\n", stderr); | |
170 | fputs("Usage: prn_example -[options]\n", stderr); | |
171 | fputs("Options:\n", stderr); | |
172 | fputs("\n", stderr); | |
173 | fputs("-get_status Get the current printer status.\n", stderr); | |
174 | fputs("-selected Set the selected status to selected.\n", stderr); | |
175 | fputs("-not_selected Set the selected status to NOT selected.\n", | |
176 | stderr); | |
177 | fputs("-error Set the error status to error.\n", stderr); | |
178 | fputs("-no_error Set the error status to NO error.\n", stderr); | |
179 | fputs("-paper_out Set the paper status to paper out.\n", stderr); | |
180 | fputs("-paper_loaded Set the paper status to paper loaded.\n", | |
181 | stderr); | |
182 | fputs("-read_data Read printer data from driver.\n", stderr); | |
183 | fputs("-write_data Write printer sata to driver.\n", stderr); | |
184 | fputs("-NB_read_data (Non-Blocking) Read printer data from driver.\n", | |
185 | stderr); | |
186 | fputs("\n\n", stderr); | |
187 | ||
188 | exit(1); | |
189 | } | |
190 | ||
191 | ||
192 | static int | |
193 | read_printer_data() | |
194 | { | |
195 | struct pollfd fd[1]; | |
196 | ||
197 | /* Open device file for printer gadget. */ | |
198 | fd[0].fd = open(PRINTER_FILE, O_RDWR); | |
199 | if (fd[0].fd < 0) { | |
200 | printf("Error %d opening %s\n", fd[0].fd, PRINTER_FILE); | |
201 | close(fd[0].fd); | |
202 | return(-1); | |
203 | } | |
204 | ||
205 | fd[0].events = POLLIN | POLLRDNORM; | |
206 | ||
207 | while (1) { | |
208 | static char buf[BUF_SIZE]; | |
209 | int bytes_read; | |
210 | int retval; | |
211 | ||
212 | /* Wait for up to 1 second for data. */ | |
213 | retval = poll(fd, 1, 1000); | |
214 | ||
215 | if (retval && (fd[0].revents & POLLRDNORM)) { | |
216 | ||
217 | /* Read data from printer gadget driver. */ | |
218 | bytes_read = read(fd[0].fd, buf, BUF_SIZE); | |
219 | ||
220 | if (bytes_read < 0) { | |
221 | printf("Error %d reading from %s\n", | |
222 | fd[0].fd, PRINTER_FILE); | |
223 | close(fd[0].fd); | |
224 | return(-1); | |
225 | } else if (bytes_read > 0) { | |
226 | /* Write data to standard OUTPUT (stdout). */ | |
227 | fwrite(buf, 1, bytes_read, stdout); | |
228 | fflush(stdout); | |
229 | } | |
230 | ||
231 | } | |
232 | ||
233 | } | |
234 | ||
235 | /* Close the device file. */ | |
236 | close(fd[0].fd); | |
237 | ||
238 | return 0; | |
239 | } | |
240 | ||
241 | ||
242 | static int | |
243 | write_printer_data() | |
244 | { | |
245 | struct pollfd fd[1]; | |
246 | ||
247 | /* Open device file for printer gadget. */ | |
248 | fd[0].fd = open (PRINTER_FILE, O_RDWR); | |
249 | if (fd[0].fd < 0) { | |
250 | printf("Error %d opening %s\n", fd[0].fd, PRINTER_FILE); | |
251 | close(fd[0].fd); | |
252 | return(-1); | |
253 | } | |
254 | ||
255 | fd[0].events = POLLOUT | POLLWRNORM; | |
256 | ||
257 | while (1) { | |
258 | int retval; | |
259 | static char buf[BUF_SIZE]; | |
260 | /* Read data from standard INPUT (stdin). */ | |
261 | int bytes_read = fread(buf, 1, BUF_SIZE, stdin); | |
262 | ||
263 | if (!bytes_read) { | |
264 | break; | |
265 | } | |
266 | ||
267 | while (bytes_read) { | |
268 | ||
269 | /* Wait for up to 1 second to sent data. */ | |
270 | retval = poll(fd, 1, 1000); | |
271 | ||
272 | /* Write data to printer gadget driver. */ | |
273 | if (retval && (fd[0].revents & POLLWRNORM)) { | |
274 | retval = write(fd[0].fd, buf, bytes_read); | |
275 | if (retval < 0) { | |
276 | printf("Error %d writing to %s\n", | |
277 | fd[0].fd, | |
278 | PRINTER_FILE); | |
279 | close(fd[0].fd); | |
280 | return(-1); | |
281 | } else { | |
282 | bytes_read -= retval; | |
283 | } | |
284 | ||
285 | } | |
286 | ||
287 | } | |
288 | ||
289 | } | |
290 | ||
291 | /* Wait until the data has been sent. */ | |
292 | fsync(fd[0].fd); | |
293 | ||
294 | /* Close the device file. */ | |
295 | close(fd[0].fd); | |
296 | ||
297 | return 0; | |
298 | } | |
299 | ||
300 | ||
301 | static int | |
302 | read_NB_printer_data() | |
303 | { | |
304 | int fd; | |
305 | static char buf[BUF_SIZE]; | |
306 | int bytes_read; | |
307 | ||
308 | /* Open device file for printer gadget. */ | |
309 | fd = open(PRINTER_FILE, O_RDWR|O_NONBLOCK); | |
310 | if (fd < 0) { | |
311 | printf("Error %d opening %s\n", fd, PRINTER_FILE); | |
312 | close(fd); | |
313 | return(-1); | |
314 | } | |
315 | ||
316 | while (1) { | |
317 | /* Read data from printer gadget driver. */ | |
318 | bytes_read = read(fd, buf, BUF_SIZE); | |
319 | if (bytes_read <= 0) { | |
320 | break; | |
321 | } | |
322 | ||
323 | /* Write data to standard OUTPUT (stdout). */ | |
324 | fwrite(buf, 1, bytes_read, stdout); | |
325 | fflush(stdout); | |
326 | } | |
327 | ||
328 | /* Close the device file. */ | |
329 | close(fd); | |
330 | ||
331 | return 0; | |
332 | } | |
333 | ||
334 | ||
335 | static int | |
336 | get_printer_status() | |
337 | { | |
338 | int retval; | |
339 | int fd; | |
340 | ||
341 | /* Open device file for printer gadget. */ | |
342 | fd = open(PRINTER_FILE, O_RDWR); | |
343 | if (fd < 0) { | |
344 | printf("Error %d opening %s\n", fd, PRINTER_FILE); | |
345 | close(fd); | |
346 | return(-1); | |
347 | } | |
348 | ||
349 | /* Make the IOCTL call. */ | |
350 | retval = ioctl(fd, GADGET_GET_PRINTER_STATUS); | |
351 | if (retval < 0) { | |
352 | fprintf(stderr, "ERROR: Failed to set printer status\n"); | |
353 | return(-1); | |
354 | } | |
355 | ||
356 | /* Close the device file. */ | |
357 | close(fd); | |
358 | ||
359 | return(retval); | |
360 | } | |
361 | ||
362 | ||
363 | static int | |
364 | set_printer_status(unsigned char buf, int clear_printer_status_bit) | |
365 | { | |
366 | int retval; | |
367 | int fd; | |
368 | ||
369 | retval = get_printer_status(); | |
370 | if (retval < 0) { | |
371 | fprintf(stderr, "ERROR: Failed to get printer status\n"); | |
372 | return(-1); | |
373 | } | |
374 | ||
375 | /* Open device file for printer gadget. */ | |
376 | fd = open(PRINTER_FILE, O_RDWR); | |
377 | ||
378 | if (fd < 0) { | |
379 | printf("Error %d opening %s\n", fd, PRINTER_FILE); | |
380 | close(fd); | |
381 | return(-1); | |
382 | } | |
383 | ||
384 | if (clear_printer_status_bit) { | |
385 | retval &= ~buf; | |
386 | } else { | |
387 | retval |= buf; | |
388 | } | |
389 | ||
390 | /* Make the IOCTL call. */ | |
391 | if (ioctl(fd, GADGET_SET_PRINTER_STATUS, (unsigned char)retval)) { | |
392 | fprintf(stderr, "ERROR: Failed to set printer status\n"); | |
393 | return(-1); | |
394 | } | |
395 | ||
396 | /* Close the device file. */ | |
397 | close(fd); | |
398 | ||
399 | return 0; | |
400 | } | |
401 | ||
402 | ||
403 | static int | |
404 | display_printer_status() | |
405 | { | |
406 | char printer_status; | |
407 | ||
408 | printer_status = get_printer_status(); | |
409 | if (printer_status < 0) { | |
410 | fprintf(stderr, "ERROR: Failed to get printer status\n"); | |
411 | return(-1); | |
412 | } | |
413 | ||
414 | printf("Printer status is:\n"); | |
415 | if (printer_status & PRINTER_SELECTED) { | |
416 | printf(" Printer is Selected\n"); | |
417 | } else { | |
418 | printf(" Printer is NOT Selected\n"); | |
419 | } | |
420 | if (printer_status & PRINTER_PAPER_EMPTY) { | |
421 | printf(" Paper is Out\n"); | |
422 | } else { | |
423 | printf(" Paper is Loaded\n"); | |
424 | } | |
425 | if (printer_status & PRINTER_NOT_ERROR) { | |
426 | printf(" Printer OK\n"); | |
427 | } else { | |
428 | printf(" Printer ERROR\n"); | |
429 | } | |
430 | ||
431 | return(0); | |
432 | } | |
433 | ||
434 | ||
435 | int | |
436 | main(int argc, char *argv[]) | |
437 | { | |
438 | int i; /* Looping var */ | |
439 | int retval = 0; | |
440 | ||
441 | /* No Args */ | |
442 | if (argc == 1) { | |
443 | usage(0); | |
444 | exit(0); | |
445 | } | |
446 | ||
447 | for (i = 1; i < argc && !retval; i ++) { | |
448 | ||
449 | if (argv[i][0] != '-') { | |
450 | continue; | |
451 | } | |
452 | ||
453 | if (!strcmp(argv[i], "-get_status")) { | |
454 | if (display_printer_status()) { | |
455 | retval = 1; | |
456 | } | |
457 | ||
458 | } else if (!strcmp(argv[i], "-paper_loaded")) { | |
459 | if (set_printer_status(PRINTER_PAPER_EMPTY, 1)) { | |
460 | retval = 1; | |
461 | } | |
462 | ||
463 | } else if (!strcmp(argv[i], "-paper_out")) { | |
464 | if (set_printer_status(PRINTER_PAPER_EMPTY, 0)) { | |
465 | retval = 1; | |
466 | } | |
467 | ||
468 | } else if (!strcmp(argv[i], "-selected")) { | |
469 | if (set_printer_status(PRINTER_SELECTED, 0)) { | |
470 | retval = 1; | |
471 | } | |
472 | ||
473 | } else if (!strcmp(argv[i], "-not_selected")) { | |
474 | if (set_printer_status(PRINTER_SELECTED, 1)) { | |
475 | retval = 1; | |
476 | } | |
477 | ||
478 | } else if (!strcmp(argv[i], "-error")) { | |
479 | if (set_printer_status(PRINTER_NOT_ERROR, 1)) { | |
480 | retval = 1; | |
481 | } | |
482 | ||
483 | } else if (!strcmp(argv[i], "-no_error")) { | |
484 | if (set_printer_status(PRINTER_NOT_ERROR, 0)) { | |
485 | retval = 1; | |
486 | } | |
487 | ||
488 | } else if (!strcmp(argv[i], "-read_data")) { | |
489 | if (read_printer_data()) { | |
490 | retval = 1; | |
491 | } | |
492 | ||
493 | } else if (!strcmp(argv[i], "-write_data")) { | |
494 | if (write_printer_data()) { | |
495 | retval = 1; | |
496 | } | |
497 | ||
498 | } else if (!strcmp(argv[i], "-NB_read_data")) { | |
499 | if (read_NB_printer_data()) { | |
500 | retval = 1; | |
501 | } | |
502 | ||
503 | } else { | |
504 | usage(argv[i]); | |
505 | retval = 1; | |
506 | } | |
507 | } | |
508 | ||
509 | exit(retval); | |
510 | } |