ia64/linux-2.6.18-xen.hg

view drivers/spi/spi_butterfly.c @ 893:f994bfe9b93b

linux/blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 04 10:32:57 2009 +0100 (2009-06-04)
parents 831230e53067
children
line source
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 */
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>
26 #include <linux/spi/spi.h>
27 #include <linux/spi/spi_bitbang.h>
28 #include <linux/spi/flash.h>
30 #include <linux/mtd/partitions.h>
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 */
42 #undef HAVE_USI /* nyet */
45 /* DATA output bits (pins 2..9 == D0..D7) */
46 #define butterfly_nreset (1 << 1) /* pin 3 */
48 #define spi_sck_bit (1 << 0) /* pin 2 */
49 #define spi_mosi_bit (1 << 7) /* pin 9 */
51 #define usi_sck_bit (1 << 3) /* pin 5 */
52 #define usi_mosi_bit (1 << 4) /* pin 6 */
54 #define vcc_bits ((1 << 6) | (1 << 5)) /* pins 7, 8 */
56 /* STATUS input bits */
57 #define spi_miso_bit PARPORT_STATUS_BUSY /* pin 11 */
59 #define usi_miso_bit PARPORT_STATUS_PAPEROUT /* pin 12 */
61 /* CONTROL output bits */
62 #define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */
63 /* USI uses no chipselect */
67 static inline struct butterfly *spidev_to_pp(struct spi_device *spi)
68 {
69 return spi->controller_data;
70 }
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 }
82 struct butterfly {
83 /* REVISIT ... for now, this must be first */
84 struct spi_bitbang bitbang;
86 struct parport *port;
87 struct pardevice *pd;
89 u8 lastbyte;
91 struct spi_device *dataflash;
92 struct spi_device *butterfly;
93 struct spi_board_info info[2];
95 };
97 /*----------------------------------------------------------------------*/
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 */
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;
112 if (is_usidev(spi))
113 bit = usi_sck_bit;
114 else
115 bit = spi_sck_bit;
117 if (is_on)
118 byte |= bit;
119 else
120 byte &= ~bit;
121 parport_write_data(pp->port, byte);
122 pp->lastbyte = byte;
123 }
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;
131 if (is_usidev(spi))
132 bit = usi_mosi_bit;
133 else
134 bit = spi_mosi_bit;
136 if (is_on)
137 byte |= bit;
138 else
139 byte &= ~bit;
140 parport_write_data(pp->port, byte);
141 pp->lastbyte = byte;
142 }
144 static inline int getmiso(struct spi_device *spi)
145 {
146 struct butterfly *pp = spidev_to_pp(spi);
147 int value;
148 u8 bit;
150 if (is_usidev(spi))
151 bit = usi_miso_bit;
152 else
153 bit = spi_miso_bit;
155 /* only STATUS_BUSY is NOT negated */
156 value = !(parport_read_status(pp->port) & bit);
157 return (bit == PARPORT_STATUS_BUSY) ? value : !value;
158 }
160 static void butterfly_chipselect(struct spi_device *spi, int value)
161 {
162 struct butterfly *pp = spidev_to_pp(spi);
164 /* set default clock polarity */
165 if (value != BITBANG_CS_INACTIVE)
166 setsck(spi, spi->mode & SPI_CPOL);
168 /* no chipselect on this USI link config */
169 if (is_usidev(spi))
170 return;
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 */
176 if (spi_cs_bit == PARPORT_CONTROL_INIT)
177 value = !value;
179 parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0);
180 }
183 /* we only needed to implement one mode here, and choose SPI_MODE_0 */
185 #define spidelay(X) do{}while(0)
186 //#define spidelay ndelay
188 #define EXPAND_BITBANG_TXRX
189 #include <linux/spi/spi_bitbang.h>
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 }
199 /*----------------------------------------------------------------------*/
201 /* override default partitioning with cmdlinepart */
202 static struct mtd_partition partitions[] = { {
203 /* JFFS2 wants partitions of 4*N blocks for this device,
204 * so sectors 0 and 1 can't be partitions by themselves.
205 */
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 } };
223 static struct flash_platform_data flash = {
224 .name = "butterflash",
225 .parts = partitions,
226 .nr_parts = ARRAY_SIZE(partitions),
227 };
230 /* REVISIT remove this ugly global and its "only one" limitation */
231 static struct butterfly *butterfly;
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;
241 if (butterfly)
242 return;
244 /* REVISIT: this just _assumes_ a butterfly is there ... no probe,
245 * and no way to be selective about what it binds to.
246 */
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);
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);
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;
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;
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;
287 status = parport_claim(pd);
288 if (status < 0)
289 goto clean1;
291 /*
292 * Butterfly reset, powerup, run firmware
293 */
294 pr_debug("%s: powerup/reset Butterfly\n", p->name);
296 /* nCS for dataflash (this bit is inverted on output) */
297 parport_frob_control(pp->port, spi_cs_bit, 0);
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);
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);
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;
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.
322 */
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);
334 #ifdef HAVE_USI
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 */
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);
348 /* FIXME setup ACK for the IRQ line ... */
349 #endif
351 // dev_info(_what?_, ...)
352 pr_info("%s: AVR Butterfly\n", p->name);
353 butterfly = pp;
354 return;
356 clean2:
357 /* turn off VCC */
358 parport_write_data(pp->port, 0);
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 }
370 static void butterfly_detach(struct parport *p)
371 {
372 struct butterfly *pp;
373 struct platform_device *pdev;
374 int status;
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;
385 /* stop() unregisters child devices too */
386 pdev = to_platform_device(pp->bitbang.master->cdev.dev);
387 status = spi_bitbang_stop(&pp->bitbang);
389 /* turn off VCC */
390 parport_write_data(pp->port, 0);
391 msleep(10);
393 parport_release(pp->pd);
394 parport_unregister_device(pp->pd);
396 (void) spi_master_put(pp->bitbang.master);
398 platform_device_unregister(pdev);
399 }
401 static struct parport_driver butterfly_driver = {
402 .name = "spi_butterfly",
403 .attach = butterfly_attach,
404 .detach = butterfly_detach,
405 };
408 static int __init butterfly_init(void)
409 {
410 return parport_register_driver(&butterfly_driver);
411 }
412 device_initcall(butterfly_init);
414 static void __exit butterfly_exit(void)
415 {
416 parport_unregister_driver(&butterfly_driver);
417 }
418 module_exit(butterfly_exit);
420 MODULE_DESCRIPTION("Parport Adapter driver for AVR Butterfly");
421 MODULE_LICENSE("GPL");