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2e10c84b DB |
1 | /* |
2 | * spi_butterfly.c - parport-to-butterfly adapter | |
3 | * | |
4 | * Copyright (C) 2005 David Brownell | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
19 | */ | |
2e10c84b DB |
20 | #include <linux/kernel.h> |
21 | #include <linux/init.h> | |
22 | #include <linux/delay.h> | |
23 | #include <linux/platform_device.h> | |
24 | #include <linux/parport.h> | |
25 | ||
26 | #include <linux/spi/spi.h> | |
27 | #include <linux/spi/spi_bitbang.h> | |
28 | #include <linux/spi/flash.h> | |
29 | ||
30 | #include <linux/mtd/partitions.h> | |
31 | ||
32 | ||
33 | /* | |
34 | * This uses SPI to talk with an "AVR Butterfly", which is a $US20 card | |
35 | * with a battery powered AVR microcontroller and lots of goodies. You | |
36 | * can use GCC to develop firmware for this. | |
37 | * | |
38 | * See Documentation/spi/butterfly for information about how to build | |
39 | * and use this custom parallel port cable. | |
40 | */ | |
41 | ||
42 | #undef HAVE_USI /* nyet */ | |
43 | ||
44 | ||
45 | /* DATA output bits (pins 2..9 == D0..D7) */ | |
46 | #define butterfly_nreset (1 << 1) /* pin 3 */ | |
47 | ||
48 | #define spi_sck_bit (1 << 0) /* pin 2 */ | |
49 | #define spi_mosi_bit (1 << 7) /* pin 9 */ | |
50 | ||
51 | #define usi_sck_bit (1 << 3) /* pin 5 */ | |
52 | #define usi_mosi_bit (1 << 4) /* pin 6 */ | |
53 | ||
54 | #define vcc_bits ((1 << 6) | (1 << 5)) /* pins 7, 8 */ | |
55 | ||
56 | /* STATUS input bits */ | |
57 | #define spi_miso_bit PARPORT_STATUS_BUSY /* pin 11 */ | |
58 | ||
59 | #define usi_miso_bit PARPORT_STATUS_PAPEROUT /* pin 12 */ | |
60 | ||
61 | /* CONTROL output bits */ | |
62 | #define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */ | |
63 | /* USI uses no chipselect */ | |
64 | ||
65 | ||
66 | ||
67 | static inline struct butterfly *spidev_to_pp(struct spi_device *spi) | |
68 | { | |
69 | return spi->controller_data; | |
70 | } | |
71 | ||
72 | static inline int is_usidev(struct spi_device *spi) | |
73 | { | |
74 | #ifdef HAVE_USI | |
75 | return spi->chip_select != 1; | |
76 | #else | |
77 | return 0; | |
78 | #endif | |
79 | } | |
80 | ||
81 | ||
82 | struct butterfly { | |
83 | /* REVISIT ... for now, this must be first */ | |
84 | struct spi_bitbang bitbang; | |
85 | ||
86 | struct parport *port; | |
87 | struct pardevice *pd; | |
88 | ||
89 | u8 lastbyte; | |
90 | ||
91 | struct spi_device *dataflash; | |
92 | struct spi_device *butterfly; | |
93 | struct spi_board_info info[2]; | |
94 | ||
95 | }; | |
96 | ||
97 | /*----------------------------------------------------------------------*/ | |
98 | ||
99 | /* | |
100 | * these routines may be slower than necessary because they're hiding | |
101 | * the fact that there are two different SPI busses on this cable: one | |
102 | * to the DataFlash chip (or AVR SPI controller), the other to the | |
103 | * AVR USI controller. | |
104 | */ | |
105 | ||
106 | static inline void | |
107 | setsck(struct spi_device *spi, int is_on) | |
108 | { | |
109 | struct butterfly *pp = spidev_to_pp(spi); | |
110 | u8 bit, byte = pp->lastbyte; | |
111 | ||
112 | if (is_usidev(spi)) | |
113 | bit = usi_sck_bit; | |
114 | else | |
115 | bit = spi_sck_bit; | |
116 | ||
117 | if (is_on) | |
118 | byte |= bit; | |
119 | else | |
120 | byte &= ~bit; | |
121 | parport_write_data(pp->port, byte); | |
122 | pp->lastbyte = byte; | |
123 | } | |
124 | ||
125 | static inline void | |
126 | setmosi(struct spi_device *spi, int is_on) | |
127 | { | |
128 | struct butterfly *pp = spidev_to_pp(spi); | |
129 | u8 bit, byte = pp->lastbyte; | |
130 | ||
131 | if (is_usidev(spi)) | |
132 | bit = usi_mosi_bit; | |
133 | else | |
134 | bit = spi_mosi_bit; | |
135 | ||
136 | if (is_on) | |
137 | byte |= bit; | |
138 | else | |
139 | byte &= ~bit; | |
140 | parport_write_data(pp->port, byte); | |
141 | pp->lastbyte = byte; | |
142 | } | |
143 | ||
144 | static inline int getmiso(struct spi_device *spi) | |
145 | { | |
146 | struct butterfly *pp = spidev_to_pp(spi); | |
147 | int value; | |
148 | u8 bit; | |
149 | ||
150 | if (is_usidev(spi)) | |
151 | bit = usi_miso_bit; | |
152 | else | |
153 | bit = spi_miso_bit; | |
154 | ||
155 | /* only STATUS_BUSY is NOT negated */ | |
156 | value = !(parport_read_status(pp->port) & bit); | |
157 | return (bit == PARPORT_STATUS_BUSY) ? value : !value; | |
158 | } | |
159 | ||
160 | static void butterfly_chipselect(struct spi_device *spi, int value) | |
161 | { | |
162 | struct butterfly *pp = spidev_to_pp(spi); | |
163 | ||
164 | /* set default clock polarity */ | |
9c1da3cb | 165 | if (value != BITBANG_CS_INACTIVE) |
2e10c84b DB |
166 | setsck(spi, spi->mode & SPI_CPOL); |
167 | ||
168 | /* no chipselect on this USI link config */ | |
169 | if (is_usidev(spi)) | |
170 | return; | |
171 | ||
9c1da3cb DB |
172 | /* here, value == "activate or not"; |
173 | * most PARPORT_CONTROL_* bits are negated, so we must | |
174 | * morph it to value == "bit value to write in control register" | |
175 | */ | |
2e10c84b DB |
176 | if (spi_cs_bit == PARPORT_CONTROL_INIT) |
177 | value = !value; | |
178 | ||
2e10c84b DB |
179 | parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0); |
180 | } | |
181 | ||
182 | ||
183 | /* we only needed to implement one mode here, and choose SPI_MODE_0 */ | |
184 | ||
185 | #define spidelay(X) do{}while(0) | |
186 | //#define spidelay ndelay | |
187 | ||
188 | #define EXPAND_BITBANG_TXRX | |
189 | #include <linux/spi/spi_bitbang.h> | |
190 | ||
191 | static u32 | |
192 | butterfly_txrx_word_mode0(struct spi_device *spi, | |
193 | unsigned nsecs, | |
194 | u32 word, u8 bits) | |
195 | { | |
196 | return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits); | |
197 | } | |
198 | ||
199 | /*----------------------------------------------------------------------*/ | |
200 | ||
201 | /* override default partitioning with cmdlinepart */ | |
202 | static struct mtd_partition partitions[] = { { | |
9c1da3cb DB |
203 | /* JFFS2 wants partitions of 4*N blocks for this device, |
204 | * so sectors 0 and 1 can't be partitions by themselves. | |
205 | */ | |
2e10c84b DB |
206 | |
207 | /* sector 0 = 8 pages * 264 bytes/page (1 block) | |
208 | * sector 1 = 248 pages * 264 bytes/page | |
209 | */ | |
210 | .name = "bookkeeping", // 66 KB | |
211 | .offset = 0, | |
212 | .size = (8 + 248) * 264, | |
213 | // .mask_flags = MTD_WRITEABLE, | |
214 | }, { | |
215 | /* sector 2 = 256 pages * 264 bytes/page | |
216 | * sectors 3-5 = 512 pages * 264 bytes/page | |
217 | */ | |
218 | .name = "filesystem", // 462 KB | |
219 | .offset = MTDPART_OFS_APPEND, | |
220 | .size = MTDPART_SIZ_FULL, | |
221 | } }; | |
222 | ||
223 | static struct flash_platform_data flash = { | |
224 | .name = "butterflash", | |
225 | .parts = partitions, | |
226 | .nr_parts = ARRAY_SIZE(partitions), | |
227 | }; | |
228 | ||
229 | ||
230 | /* REVISIT remove this ugly global and its "only one" limitation */ | |
231 | static struct butterfly *butterfly; | |
232 | ||
233 | static void butterfly_attach(struct parport *p) | |
234 | { | |
235 | struct pardevice *pd; | |
236 | int status; | |
237 | struct butterfly *pp; | |
238 | struct spi_master *master; | |
239 | struct platform_device *pdev; | |
240 | ||
241 | if (butterfly) | |
242 | return; | |
243 | ||
244 | /* REVISIT: this just _assumes_ a butterfly is there ... no probe, | |
245 | * and no way to be selective about what it binds to. | |
246 | */ | |
247 | ||
248 | /* FIXME where should master->cdev.dev come from? | |
249 | * e.g. /sys/bus/pnp0/00:0b, some PCI thing, etc | |
250 | * setting up a platform device like this is an ugly kluge... | |
251 | */ | |
252 | pdev = platform_device_register_simple("butterfly", -1, NULL, 0); | |
253 | ||
254 | master = spi_alloc_master(&pdev->dev, sizeof *pp); | |
255 | if (!master) { | |
256 | status = -ENOMEM; | |
257 | goto done; | |
258 | } | |
259 | pp = spi_master_get_devdata(master); | |
260 | ||
261 | /* | |
262 | * SPI and bitbang hookup | |
263 | * | |
264 | * use default setup(), cleanup(), and transfer() methods; and | |
265 | * only bother implementing mode 0. Start it later. | |
266 | */ | |
267 | master->bus_num = 42; | |
268 | master->num_chipselect = 2; | |
269 | ||
270 | pp->bitbang.master = spi_master_get(master); | |
271 | pp->bitbang.chipselect = butterfly_chipselect; | |
272 | pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0; | |
273 | ||
274 | /* | |
275 | * parport hookup | |
276 | */ | |
277 | pp->port = p; | |
278 | pd = parport_register_device(p, "spi_butterfly", | |
279 | NULL, NULL, NULL, | |
280 | 0 /* FLAGS */, pp); | |
281 | if (!pd) { | |
282 | status = -ENOMEM; | |
283 | goto clean0; | |
284 | } | |
285 | pp->pd = pd; | |
286 | ||
287 | status = parport_claim(pd); | |
288 | if (status < 0) | |
289 | goto clean1; | |
290 | ||
291 | /* | |
292 | * Butterfly reset, powerup, run firmware | |
293 | */ | |
294 | pr_debug("%s: powerup/reset Butterfly\n", p->name); | |
295 | ||
296 | /* nCS for dataflash (this bit is inverted on output) */ | |
297 | parport_frob_control(pp->port, spi_cs_bit, 0); | |
298 | ||
299 | /* stabilize power with chip in reset (nRESET), and | |
300 | * both spi_sck_bit and usi_sck_bit clear (CPOL=0) | |
301 | */ | |
302 | pp->lastbyte |= vcc_bits; | |
303 | parport_write_data(pp->port, pp->lastbyte); | |
304 | msleep(5); | |
305 | ||
306 | /* take it out of reset; assume long reset delay */ | |
307 | pp->lastbyte |= butterfly_nreset; | |
308 | parport_write_data(pp->port, pp->lastbyte); | |
309 | msleep(100); | |
310 | ||
311 | ||
312 | /* | |
313 | * Start SPI ... for now, hide that we're two physical busses. | |
314 | */ | |
315 | status = spi_bitbang_start(&pp->bitbang); | |
316 | if (status < 0) | |
317 | goto clean2; | |
318 | ||
9c1da3cb DB |
319 | /* Bus 1 lets us talk to at45db041b (firmware disables AVR SPI), AVR |
320 | * (firmware resets at45, acts as spi slave) or neither (we ignore | |
321 | * both, AVR uses AT45). Here we expect firmware for the first option. | |
2e10c84b | 322 | */ |
1fc7547d | 323 | |
2e10c84b DB |
324 | pp->info[0].max_speed_hz = 15 * 1000 * 1000; |
325 | strcpy(pp->info[0].modalias, "mtd_dataflash"); | |
326 | pp->info[0].platform_data = &flash; | |
327 | pp->info[0].chip_select = 1; | |
328 | pp->info[0].controller_data = pp; | |
329 | pp->dataflash = spi_new_device(pp->bitbang.master, &pp->info[0]); | |
330 | if (pp->dataflash) | |
331 | pr_debug("%s: dataflash at %s\n", p->name, | |
332 | pp->dataflash->dev.bus_id); | |
333 | ||
334 | #ifdef HAVE_USI | |
9c1da3cb DB |
335 | /* Bus 2 is only for talking to the AVR, and it can work no |
336 | * matter who masters bus 1; needs appropriate AVR firmware. | |
337 | */ | |
2e10c84b DB |
338 | pp->info[1].max_speed_hz = 10 /* ?? */ * 1000 * 1000; |
339 | strcpy(pp->info[1].modalias, "butterfly"); | |
340 | // pp->info[1].platform_data = ... TBD ... ; | |
341 | pp->info[1].chip_select = 2, | |
342 | pp->info[1].controller_data = pp; | |
343 | pp->butterfly = spi_new_device(pp->bitbang.master, &pp->info[1]); | |
344 | if (pp->butterfly) | |
345 | pr_debug("%s: butterfly at %s\n", p->name, | |
346 | pp->butterfly->dev.bus_id); | |
347 | ||
348 | /* FIXME setup ACK for the IRQ line ... */ | |
349 | #endif | |
350 | ||
351 | // dev_info(_what?_, ...) | |
352 | pr_info("%s: AVR Butterfly\n", p->name); | |
353 | butterfly = pp; | |
354 | return; | |
355 | ||
356 | clean2: | |
357 | /* turn off VCC */ | |
358 | parport_write_data(pp->port, 0); | |
359 | ||
360 | parport_release(pp->pd); | |
361 | clean1: | |
362 | parport_unregister_device(pd); | |
363 | clean0: | |
364 | (void) spi_master_put(pp->bitbang.master); | |
365 | done: | |
366 | platform_device_unregister(pdev); | |
367 | pr_debug("%s: butterfly probe, fail %d\n", p->name, status); | |
368 | } | |
369 | ||
370 | static void butterfly_detach(struct parport *p) | |
371 | { | |
372 | struct butterfly *pp; | |
373 | struct platform_device *pdev; | |
374 | int status; | |
375 | ||
376 | /* FIXME this global is ugly ... but, how to quickly get from | |
377 | * the parport to the "struct butterfly" associated with it? | |
378 | * "old school" driver-internal device lists? | |
379 | */ | |
380 | if (!butterfly || butterfly->port != p) | |
381 | return; | |
382 | pp = butterfly; | |
383 | butterfly = NULL; | |
384 | ||
9c1da3cb DB |
385 | /* stop() unregisters child devices too */ |
386 | pdev = to_platform_device(pp->bitbang.master->cdev.dev); | |
2e10c84b DB |
387 | status = spi_bitbang_stop(&pp->bitbang); |
388 | ||
389 | /* turn off VCC */ | |
390 | parport_write_data(pp->port, 0); | |
391 | msleep(10); | |
392 | ||
393 | parport_release(pp->pd); | |
394 | parport_unregister_device(pp->pd); | |
395 | ||
2e10c84b DB |
396 | (void) spi_master_put(pp->bitbang.master); |
397 | ||
398 | platform_device_unregister(pdev); | |
399 | } | |
400 | ||
401 | static struct parport_driver butterfly_driver = { | |
402 | .name = "spi_butterfly", | |
403 | .attach = butterfly_attach, | |
404 | .detach = butterfly_detach, | |
405 | }; | |
406 | ||
407 | ||
408 | static int __init butterfly_init(void) | |
409 | { | |
410 | return parport_register_driver(&butterfly_driver); | |
411 | } | |
412 | device_initcall(butterfly_init); | |
413 | ||
414 | static void __exit butterfly_exit(void) | |
415 | { | |
416 | parport_unregister_driver(&butterfly_driver); | |
417 | } | |
418 | module_exit(butterfly_exit); | |
419 | ||
9c1da3cb | 420 | MODULE_DESCRIPTION("Parport Adapter driver for AVR Butterfly"); |
2e10c84b | 421 | MODULE_LICENSE("GPL"); |