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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> | |
da675296 | 23 | #include <linux/device.h> |
2e10c84b DB |
24 | #include <linux/parport.h> |
25 | ||
914e2637 | 26 | #include <linux/sched.h> |
2e10c84b DB |
27 | #include <linux/spi/spi.h> |
28 | #include <linux/spi/spi_bitbang.h> | |
29 | #include <linux/spi/flash.h> | |
30 | ||
31 | #include <linux/mtd/partitions.h> | |
32 | ||
33 | ||
34 | /* | |
35 | * This uses SPI to talk with an "AVR Butterfly", which is a $US20 card | |
36 | * with a battery powered AVR microcontroller and lots of goodies. You | |
37 | * can use GCC to develop firmware for this. | |
38 | * | |
39 | * See Documentation/spi/butterfly for information about how to build | |
40 | * and use this custom parallel port cable. | |
41 | */ | |
42 | ||
2e10c84b DB |
43 | |
44 | /* DATA output bits (pins 2..9 == D0..D7) */ | |
45 | #define butterfly_nreset (1 << 1) /* pin 3 */ | |
46 | ||
47 | #define spi_sck_bit (1 << 0) /* pin 2 */ | |
48 | #define spi_mosi_bit (1 << 7) /* pin 9 */ | |
49 | ||
2e10c84b DB |
50 | #define vcc_bits ((1 << 6) | (1 << 5)) /* pins 7, 8 */ |
51 | ||
52 | /* STATUS input bits */ | |
53 | #define spi_miso_bit PARPORT_STATUS_BUSY /* pin 11 */ | |
54 | ||
2e10c84b DB |
55 | /* CONTROL output bits */ |
56 | #define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */ | |
2e10c84b DB |
57 | |
58 | ||
59 | ||
60 | static inline struct butterfly *spidev_to_pp(struct spi_device *spi) | |
61 | { | |
62 | return spi->controller_data; | |
63 | } | |
64 | ||
2e10c84b DB |
65 | |
66 | struct butterfly { | |
67 | /* REVISIT ... for now, this must be first */ | |
68 | struct spi_bitbang bitbang; | |
69 | ||
70 | struct parport *port; | |
71 | struct pardevice *pd; | |
72 | ||
73 | u8 lastbyte; | |
74 | ||
75 | struct spi_device *dataflash; | |
76 | struct spi_device *butterfly; | |
77 | struct spi_board_info info[2]; | |
78 | ||
79 | }; | |
80 | ||
81 | /*----------------------------------------------------------------------*/ | |
82 | ||
2e10c84b DB |
83 | static inline void |
84 | setsck(struct spi_device *spi, int is_on) | |
85 | { | |
86 | struct butterfly *pp = spidev_to_pp(spi); | |
87 | u8 bit, byte = pp->lastbyte; | |
88 | ||
735ce95e | 89 | bit = spi_sck_bit; |
2e10c84b DB |
90 | |
91 | if (is_on) | |
92 | byte |= bit; | |
93 | else | |
94 | byte &= ~bit; | |
95 | parport_write_data(pp->port, byte); | |
96 | pp->lastbyte = byte; | |
97 | } | |
98 | ||
99 | static inline void | |
100 | setmosi(struct spi_device *spi, int is_on) | |
101 | { | |
102 | struct butterfly *pp = spidev_to_pp(spi); | |
103 | u8 bit, byte = pp->lastbyte; | |
104 | ||
735ce95e | 105 | bit = spi_mosi_bit; |
2e10c84b DB |
106 | |
107 | if (is_on) | |
108 | byte |= bit; | |
109 | else | |
110 | byte &= ~bit; | |
111 | parport_write_data(pp->port, byte); | |
112 | pp->lastbyte = byte; | |
113 | } | |
114 | ||
115 | static inline int getmiso(struct spi_device *spi) | |
116 | { | |
117 | struct butterfly *pp = spidev_to_pp(spi); | |
118 | int value; | |
119 | u8 bit; | |
120 | ||
735ce95e | 121 | bit = spi_miso_bit; |
2e10c84b DB |
122 | |
123 | /* only STATUS_BUSY is NOT negated */ | |
124 | value = !(parport_read_status(pp->port) & bit); | |
125 | return (bit == PARPORT_STATUS_BUSY) ? value : !value; | |
126 | } | |
127 | ||
128 | static void butterfly_chipselect(struct spi_device *spi, int value) | |
129 | { | |
130 | struct butterfly *pp = spidev_to_pp(spi); | |
131 | ||
132 | /* set default clock polarity */ | |
9c1da3cb | 133 | if (value != BITBANG_CS_INACTIVE) |
2e10c84b DB |
134 | setsck(spi, spi->mode & SPI_CPOL); |
135 | ||
9c1da3cb DB |
136 | /* here, value == "activate or not"; |
137 | * most PARPORT_CONTROL_* bits are negated, so we must | |
138 | * morph it to value == "bit value to write in control register" | |
139 | */ | |
2e10c84b DB |
140 | if (spi_cs_bit == PARPORT_CONTROL_INIT) |
141 | value = !value; | |
142 | ||
2e10c84b DB |
143 | parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0); |
144 | } | |
145 | ||
146 | ||
147 | /* we only needed to implement one mode here, and choose SPI_MODE_0 */ | |
148 | ||
149 | #define spidelay(X) do{}while(0) | |
150 | //#define spidelay ndelay | |
151 | ||
152 | #define EXPAND_BITBANG_TXRX | |
153 | #include <linux/spi/spi_bitbang.h> | |
154 | ||
155 | static u32 | |
156 | butterfly_txrx_word_mode0(struct spi_device *spi, | |
157 | unsigned nsecs, | |
158 | u32 word, u8 bits) | |
159 | { | |
160 | return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits); | |
161 | } | |
162 | ||
163 | /*----------------------------------------------------------------------*/ | |
164 | ||
165 | /* override default partitioning with cmdlinepart */ | |
166 | static struct mtd_partition partitions[] = { { | |
9c1da3cb DB |
167 | /* JFFS2 wants partitions of 4*N blocks for this device, |
168 | * so sectors 0 and 1 can't be partitions by themselves. | |
169 | */ | |
2e10c84b DB |
170 | |
171 | /* sector 0 = 8 pages * 264 bytes/page (1 block) | |
172 | * sector 1 = 248 pages * 264 bytes/page | |
173 | */ | |
174 | .name = "bookkeeping", // 66 KB | |
175 | .offset = 0, | |
176 | .size = (8 + 248) * 264, | |
177 | // .mask_flags = MTD_WRITEABLE, | |
178 | }, { | |
179 | /* sector 2 = 256 pages * 264 bytes/page | |
180 | * sectors 3-5 = 512 pages * 264 bytes/page | |
181 | */ | |
182 | .name = "filesystem", // 462 KB | |
183 | .offset = MTDPART_OFS_APPEND, | |
184 | .size = MTDPART_SIZ_FULL, | |
185 | } }; | |
186 | ||
187 | static struct flash_platform_data flash = { | |
188 | .name = "butterflash", | |
189 | .parts = partitions, | |
190 | .nr_parts = ARRAY_SIZE(partitions), | |
191 | }; | |
192 | ||
193 | ||
194 | /* REVISIT remove this ugly global and its "only one" limitation */ | |
195 | static struct butterfly *butterfly; | |
196 | ||
197 | static void butterfly_attach(struct parport *p) | |
198 | { | |
199 | struct pardevice *pd; | |
200 | int status; | |
201 | struct butterfly *pp; | |
202 | struct spi_master *master; | |
da675296 | 203 | struct device *dev = p->physport->dev; |
2e10c84b | 204 | |
da675296 | 205 | if (butterfly || !dev) |
2e10c84b DB |
206 | return; |
207 | ||
208 | /* REVISIT: this just _assumes_ a butterfly is there ... no probe, | |
209 | * and no way to be selective about what it binds to. | |
210 | */ | |
211 | ||
da675296 | 212 | master = spi_alloc_master(dev, sizeof *pp); |
2e10c84b DB |
213 | if (!master) { |
214 | status = -ENOMEM; | |
215 | goto done; | |
216 | } | |
217 | pp = spi_master_get_devdata(master); | |
218 | ||
219 | /* | |
220 | * SPI and bitbang hookup | |
221 | * | |
222 | * use default setup(), cleanup(), and transfer() methods; and | |
223 | * only bother implementing mode 0. Start it later. | |
224 | */ | |
225 | master->bus_num = 42; | |
226 | master->num_chipselect = 2; | |
227 | ||
228 | pp->bitbang.master = spi_master_get(master); | |
229 | pp->bitbang.chipselect = butterfly_chipselect; | |
230 | pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0; | |
231 | ||
232 | /* | |
233 | * parport hookup | |
234 | */ | |
235 | pp->port = p; | |
236 | pd = parport_register_device(p, "spi_butterfly", | |
237 | NULL, NULL, NULL, | |
238 | 0 /* FLAGS */, pp); | |
239 | if (!pd) { | |
240 | status = -ENOMEM; | |
241 | goto clean0; | |
242 | } | |
243 | pp->pd = pd; | |
244 | ||
245 | status = parport_claim(pd); | |
246 | if (status < 0) | |
247 | goto clean1; | |
248 | ||
249 | /* | |
250 | * Butterfly reset, powerup, run firmware | |
251 | */ | |
252 | pr_debug("%s: powerup/reset Butterfly\n", p->name); | |
253 | ||
254 | /* nCS for dataflash (this bit is inverted on output) */ | |
255 | parport_frob_control(pp->port, spi_cs_bit, 0); | |
256 | ||
257 | /* stabilize power with chip in reset (nRESET), and | |
735ce95e | 258 | * spi_sck_bit clear (CPOL=0) |
2e10c84b DB |
259 | */ |
260 | pp->lastbyte |= vcc_bits; | |
261 | parport_write_data(pp->port, pp->lastbyte); | |
262 | msleep(5); | |
263 | ||
264 | /* take it out of reset; assume long reset delay */ | |
265 | pp->lastbyte |= butterfly_nreset; | |
266 | parport_write_data(pp->port, pp->lastbyte); | |
267 | msleep(100); | |
268 | ||
269 | ||
270 | /* | |
271 | * Start SPI ... for now, hide that we're two physical busses. | |
272 | */ | |
273 | status = spi_bitbang_start(&pp->bitbang); | |
274 | if (status < 0) | |
275 | goto clean2; | |
276 | ||
9c1da3cb DB |
277 | /* Bus 1 lets us talk to at45db041b (firmware disables AVR SPI), AVR |
278 | * (firmware resets at45, acts as spi slave) or neither (we ignore | |
279 | * both, AVR uses AT45). Here we expect firmware for the first option. | |
2e10c84b | 280 | */ |
1fc7547d | 281 | |
2e10c84b DB |
282 | pp->info[0].max_speed_hz = 15 * 1000 * 1000; |
283 | strcpy(pp->info[0].modalias, "mtd_dataflash"); | |
284 | pp->info[0].platform_data = &flash; | |
285 | pp->info[0].chip_select = 1; | |
286 | pp->info[0].controller_data = pp; | |
287 | pp->dataflash = spi_new_device(pp->bitbang.master, &pp->info[0]); | |
288 | if (pp->dataflash) | |
289 | pr_debug("%s: dataflash at %s\n", p->name, | |
290 | pp->dataflash->dev.bus_id); | |
291 | ||
2e10c84b DB |
292 | // dev_info(_what?_, ...) |
293 | pr_info("%s: AVR Butterfly\n", p->name); | |
294 | butterfly = pp; | |
295 | return; | |
296 | ||
297 | clean2: | |
298 | /* turn off VCC */ | |
299 | parport_write_data(pp->port, 0); | |
300 | ||
301 | parport_release(pp->pd); | |
302 | clean1: | |
303 | parport_unregister_device(pd); | |
304 | clean0: | |
305 | (void) spi_master_put(pp->bitbang.master); | |
306 | done: | |
2e10c84b DB |
307 | pr_debug("%s: butterfly probe, fail %d\n", p->name, status); |
308 | } | |
309 | ||
310 | static void butterfly_detach(struct parport *p) | |
311 | { | |
312 | struct butterfly *pp; | |
2e10c84b DB |
313 | int status; |
314 | ||
315 | /* FIXME this global is ugly ... but, how to quickly get from | |
316 | * the parport to the "struct butterfly" associated with it? | |
317 | * "old school" driver-internal device lists? | |
318 | */ | |
319 | if (!butterfly || butterfly->port != p) | |
320 | return; | |
321 | pp = butterfly; | |
322 | butterfly = NULL; | |
323 | ||
9c1da3cb | 324 | /* stop() unregisters child devices too */ |
2e10c84b DB |
325 | status = spi_bitbang_stop(&pp->bitbang); |
326 | ||
327 | /* turn off VCC */ | |
328 | parport_write_data(pp->port, 0); | |
329 | msleep(10); | |
330 | ||
331 | parport_release(pp->pd); | |
332 | parport_unregister_device(pp->pd); | |
333 | ||
2e10c84b | 334 | (void) spi_master_put(pp->bitbang.master); |
2e10c84b DB |
335 | } |
336 | ||
337 | static struct parport_driver butterfly_driver = { | |
338 | .name = "spi_butterfly", | |
339 | .attach = butterfly_attach, | |
340 | .detach = butterfly_detach, | |
341 | }; | |
342 | ||
343 | ||
344 | static int __init butterfly_init(void) | |
345 | { | |
346 | return parport_register_driver(&butterfly_driver); | |
347 | } | |
348 | device_initcall(butterfly_init); | |
349 | ||
350 | static void __exit butterfly_exit(void) | |
351 | { | |
352 | parport_unregister_driver(&butterfly_driver); | |
353 | } | |
354 | module_exit(butterfly_exit); | |
355 | ||
9c1da3cb | 356 | MODULE_DESCRIPTION("Parport Adapter driver for AVR Butterfly"); |
2e10c84b | 357 | MODULE_LICENSE("GPL"); |