Commit | Line | Data |
---|---|---|
2e10c84b | 1 | /* |
ca632f55 | 2 | * parport-to-butterfly adapter |
2e10c84b DB |
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. | |
2e10c84b | 15 | */ |
2e10c84b DB |
16 | #include <linux/kernel.h> |
17 | #include <linux/init.h> | |
18 | #include <linux/delay.h> | |
d7614de4 | 19 | #include <linux/module.h> |
da675296 | 20 | #include <linux/device.h> |
2e10c84b DB |
21 | #include <linux/parport.h> |
22 | ||
914e2637 | 23 | #include <linux/sched.h> |
2e10c84b DB |
24 | #include <linux/spi/spi.h> |
25 | #include <linux/spi/spi_bitbang.h> | |
26 | #include <linux/spi/flash.h> | |
27 | ||
28 | #include <linux/mtd/partitions.h> | |
29 | ||
30 | ||
31 | /* | |
32 | * This uses SPI to talk with an "AVR Butterfly", which is a $US20 card | |
33 | * with a battery powered AVR microcontroller and lots of goodies. You | |
34 | * can use GCC to develop firmware for this. | |
35 | * | |
36 | * See Documentation/spi/butterfly for information about how to build | |
37 | * and use this custom parallel port cable. | |
38 | */ | |
39 | ||
2e10c84b DB |
40 | |
41 | /* DATA output bits (pins 2..9 == D0..D7) */ | |
42 | #define butterfly_nreset (1 << 1) /* pin 3 */ | |
43 | ||
44 | #define spi_sck_bit (1 << 0) /* pin 2 */ | |
45 | #define spi_mosi_bit (1 << 7) /* pin 9 */ | |
46 | ||
2e10c84b DB |
47 | #define vcc_bits ((1 << 6) | (1 << 5)) /* pins 7, 8 */ |
48 | ||
49 | /* STATUS input bits */ | |
50 | #define spi_miso_bit PARPORT_STATUS_BUSY /* pin 11 */ | |
51 | ||
2e10c84b DB |
52 | /* CONTROL output bits */ |
53 | #define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */ | |
2e10c84b DB |
54 | |
55 | ||
56 | ||
57 | static inline struct butterfly *spidev_to_pp(struct spi_device *spi) | |
58 | { | |
59 | return spi->controller_data; | |
60 | } | |
61 | ||
2e10c84b DB |
62 | |
63 | struct butterfly { | |
64 | /* REVISIT ... for now, this must be first */ | |
65 | struct spi_bitbang bitbang; | |
66 | ||
67 | struct parport *port; | |
68 | struct pardevice *pd; | |
69 | ||
70 | u8 lastbyte; | |
71 | ||
72 | struct spi_device *dataflash; | |
73 | struct spi_device *butterfly; | |
74 | struct spi_board_info info[2]; | |
75 | ||
76 | }; | |
77 | ||
78 | /*----------------------------------------------------------------------*/ | |
79 | ||
2e10c84b DB |
80 | static inline void |
81 | setsck(struct spi_device *spi, int is_on) | |
82 | { | |
83 | struct butterfly *pp = spidev_to_pp(spi); | |
84 | u8 bit, byte = pp->lastbyte; | |
85 | ||
735ce95e | 86 | bit = spi_sck_bit; |
2e10c84b DB |
87 | |
88 | if (is_on) | |
89 | byte |= bit; | |
90 | else | |
91 | byte &= ~bit; | |
92 | parport_write_data(pp->port, byte); | |
93 | pp->lastbyte = byte; | |
94 | } | |
95 | ||
96 | static inline void | |
97 | setmosi(struct spi_device *spi, int is_on) | |
98 | { | |
99 | struct butterfly *pp = spidev_to_pp(spi); | |
100 | u8 bit, byte = pp->lastbyte; | |
101 | ||
735ce95e | 102 | bit = spi_mosi_bit; |
2e10c84b DB |
103 | |
104 | if (is_on) | |
105 | byte |= bit; | |
106 | else | |
107 | byte &= ~bit; | |
108 | parport_write_data(pp->port, byte); | |
109 | pp->lastbyte = byte; | |
110 | } | |
111 | ||
112 | static inline int getmiso(struct spi_device *spi) | |
113 | { | |
114 | struct butterfly *pp = spidev_to_pp(spi); | |
115 | int value; | |
116 | u8 bit; | |
117 | ||
735ce95e | 118 | bit = spi_miso_bit; |
2e10c84b DB |
119 | |
120 | /* only STATUS_BUSY is NOT negated */ | |
121 | value = !(parport_read_status(pp->port) & bit); | |
122 | return (bit == PARPORT_STATUS_BUSY) ? value : !value; | |
123 | } | |
124 | ||
125 | static void butterfly_chipselect(struct spi_device *spi, int value) | |
126 | { | |
127 | struct butterfly *pp = spidev_to_pp(spi); | |
128 | ||
129 | /* set default clock polarity */ | |
9c1da3cb | 130 | if (value != BITBANG_CS_INACTIVE) |
2e10c84b DB |
131 | setsck(spi, spi->mode & SPI_CPOL); |
132 | ||
9c1da3cb DB |
133 | /* here, value == "activate or not"; |
134 | * most PARPORT_CONTROL_* bits are negated, so we must | |
135 | * morph it to value == "bit value to write in control register" | |
136 | */ | |
2e10c84b DB |
137 | if (spi_cs_bit == PARPORT_CONTROL_INIT) |
138 | value = !value; | |
139 | ||
2e10c84b DB |
140 | parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0); |
141 | } | |
142 | ||
143 | ||
144 | /* we only needed to implement one mode here, and choose SPI_MODE_0 */ | |
145 | ||
ac8ed236 JH |
146 | #define spidelay(X) do { } while (0) |
147 | /* #define spidelay ndelay */ | |
2e10c84b | 148 | |
ca632f55 | 149 | #include "spi-bitbang-txrx.h" |
2e10c84b DB |
150 | |
151 | static u32 | |
152 | butterfly_txrx_word_mode0(struct spi_device *spi, | |
153 | unsigned nsecs, | |
154 | u32 word, u8 bits) | |
155 | { | |
04bb2a03 | 156 | return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits); |
2e10c84b DB |
157 | } |
158 | ||
159 | /*----------------------------------------------------------------------*/ | |
160 | ||
161 | /* override default partitioning with cmdlinepart */ | |
162 | static struct mtd_partition partitions[] = { { | |
9c1da3cb DB |
163 | /* JFFS2 wants partitions of 4*N blocks for this device, |
164 | * so sectors 0 and 1 can't be partitions by themselves. | |
165 | */ | |
2e10c84b DB |
166 | |
167 | /* sector 0 = 8 pages * 264 bytes/page (1 block) | |
168 | * sector 1 = 248 pages * 264 bytes/page | |
169 | */ | |
ac8ed236 | 170 | .name = "bookkeeping", /* 66 KB */ |
2e10c84b DB |
171 | .offset = 0, |
172 | .size = (8 + 248) * 264, | |
ac8ed236 | 173 | /* .mask_flags = MTD_WRITEABLE, */ |
2e10c84b DB |
174 | }, { |
175 | /* sector 2 = 256 pages * 264 bytes/page | |
176 | * sectors 3-5 = 512 pages * 264 bytes/page | |
177 | */ | |
ac8ed236 | 178 | .name = "filesystem", /* 462 KB */ |
2e10c84b DB |
179 | .offset = MTDPART_OFS_APPEND, |
180 | .size = MTDPART_SIZ_FULL, | |
181 | } }; | |
182 | ||
183 | static struct flash_platform_data flash = { | |
184 | .name = "butterflash", | |
185 | .parts = partitions, | |
186 | .nr_parts = ARRAY_SIZE(partitions), | |
187 | }; | |
188 | ||
189 | ||
190 | /* REVISIT remove this ugly global and its "only one" limitation */ | |
191 | static struct butterfly *butterfly; | |
192 | ||
193 | static void butterfly_attach(struct parport *p) | |
194 | { | |
195 | struct pardevice *pd; | |
196 | int status; | |
197 | struct butterfly *pp; | |
198 | struct spi_master *master; | |
da675296 | 199 | struct device *dev = p->physport->dev; |
2e10c84b | 200 | |
da675296 | 201 | if (butterfly || !dev) |
2e10c84b DB |
202 | return; |
203 | ||
204 | /* REVISIT: this just _assumes_ a butterfly is there ... no probe, | |
205 | * and no way to be selective about what it binds to. | |
206 | */ | |
207 | ||
ac8ed236 | 208 | master = spi_alloc_master(dev, sizeof(*pp)); |
2e10c84b DB |
209 | if (!master) { |
210 | status = -ENOMEM; | |
211 | goto done; | |
212 | } | |
213 | pp = spi_master_get_devdata(master); | |
214 | ||
215 | /* | |
216 | * SPI and bitbang hookup | |
217 | * | |
218 | * use default setup(), cleanup(), and transfer() methods; and | |
219 | * only bother implementing mode 0. Start it later. | |
220 | */ | |
221 | master->bus_num = 42; | |
222 | master->num_chipselect = 2; | |
223 | ||
94c69f76 | 224 | pp->bitbang.master = master; |
2e10c84b DB |
225 | pp->bitbang.chipselect = butterfly_chipselect; |
226 | pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0; | |
227 | ||
228 | /* | |
229 | * parport hookup | |
230 | */ | |
231 | pp->port = p; | |
232 | pd = parport_register_device(p, "spi_butterfly", | |
233 | NULL, NULL, NULL, | |
234 | 0 /* FLAGS */, pp); | |
235 | if (!pd) { | |
236 | status = -ENOMEM; | |
237 | goto clean0; | |
238 | } | |
239 | pp->pd = pd; | |
240 | ||
241 | status = parport_claim(pd); | |
242 | if (status < 0) | |
243 | goto clean1; | |
244 | ||
245 | /* | |
246 | * Butterfly reset, powerup, run firmware | |
247 | */ | |
248 | pr_debug("%s: powerup/reset Butterfly\n", p->name); | |
249 | ||
250 | /* nCS for dataflash (this bit is inverted on output) */ | |
251 | parport_frob_control(pp->port, spi_cs_bit, 0); | |
252 | ||
253 | /* stabilize power with chip in reset (nRESET), and | |
735ce95e | 254 | * spi_sck_bit clear (CPOL=0) |
2e10c84b DB |
255 | */ |
256 | pp->lastbyte |= vcc_bits; | |
257 | parport_write_data(pp->port, pp->lastbyte); | |
258 | msleep(5); | |
259 | ||
260 | /* take it out of reset; assume long reset delay */ | |
261 | pp->lastbyte |= butterfly_nreset; | |
262 | parport_write_data(pp->port, pp->lastbyte); | |
263 | msleep(100); | |
264 | ||
265 | ||
266 | /* | |
267 | * Start SPI ... for now, hide that we're two physical busses. | |
268 | */ | |
269 | status = spi_bitbang_start(&pp->bitbang); | |
270 | if (status < 0) | |
271 | goto clean2; | |
272 | ||
9c1da3cb DB |
273 | /* Bus 1 lets us talk to at45db041b (firmware disables AVR SPI), AVR |
274 | * (firmware resets at45, acts as spi slave) or neither (we ignore | |
275 | * both, AVR uses AT45). Here we expect firmware for the first option. | |
2e10c84b | 276 | */ |
1fc7547d | 277 | |
2e10c84b DB |
278 | pp->info[0].max_speed_hz = 15 * 1000 * 1000; |
279 | strcpy(pp->info[0].modalias, "mtd_dataflash"); | |
280 | pp->info[0].platform_data = &flash; | |
281 | pp->info[0].chip_select = 1; | |
282 | pp->info[0].controller_data = pp; | |
283 | pp->dataflash = spi_new_device(pp->bitbang.master, &pp->info[0]); | |
284 | if (pp->dataflash) | |
285 | pr_debug("%s: dataflash at %s\n", p->name, | |
35f74fca | 286 | dev_name(&pp->dataflash->dev)); |
2e10c84b | 287 | |
2e10c84b DB |
288 | pr_info("%s: AVR Butterfly\n", p->name); |
289 | butterfly = pp; | |
290 | return; | |
291 | ||
292 | clean2: | |
293 | /* turn off VCC */ | |
294 | parport_write_data(pp->port, 0); | |
295 | ||
296 | parport_release(pp->pd); | |
297 | clean1: | |
298 | parport_unregister_device(pd); | |
299 | clean0: | |
300 | (void) spi_master_put(pp->bitbang.master); | |
301 | done: | |
2e10c84b DB |
302 | pr_debug("%s: butterfly probe, fail %d\n", p->name, status); |
303 | } | |
304 | ||
305 | static void butterfly_detach(struct parport *p) | |
306 | { | |
307 | struct butterfly *pp; | |
2e10c84b DB |
308 | |
309 | /* FIXME this global is ugly ... but, how to quickly get from | |
310 | * the parport to the "struct butterfly" associated with it? | |
311 | * "old school" driver-internal device lists? | |
312 | */ | |
313 | if (!butterfly || butterfly->port != p) | |
314 | return; | |
315 | pp = butterfly; | |
316 | butterfly = NULL; | |
317 | ||
9c1da3cb | 318 | /* stop() unregisters child devices too */ |
d9721ae1 | 319 | spi_bitbang_stop(&pp->bitbang); |
2e10c84b DB |
320 | |
321 | /* turn off VCC */ | |
322 | parport_write_data(pp->port, 0); | |
323 | msleep(10); | |
324 | ||
325 | parport_release(pp->pd); | |
326 | parport_unregister_device(pp->pd); | |
327 | ||
2e10c84b | 328 | (void) spi_master_put(pp->bitbang.master); |
2e10c84b DB |
329 | } |
330 | ||
331 | static struct parport_driver butterfly_driver = { | |
332 | .name = "spi_butterfly", | |
333 | .attach = butterfly_attach, | |
334 | .detach = butterfly_detach, | |
335 | }; | |
336 | ||
337 | ||
338 | static int __init butterfly_init(void) | |
339 | { | |
340 | return parport_register_driver(&butterfly_driver); | |
341 | } | |
342 | device_initcall(butterfly_init); | |
343 | ||
344 | static void __exit butterfly_exit(void) | |
345 | { | |
346 | parport_unregister_driver(&butterfly_driver); | |
347 | } | |
348 | module_exit(butterfly_exit); | |
349 | ||
9c1da3cb | 350 | MODULE_DESCRIPTION("Parport Adapter driver for AVR Butterfly"); |
2e10c84b | 351 | MODULE_LICENSE("GPL"); |