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David Brownell2e10c842006-01-11 11:23:49 -08001/*
Grant Likelyca632f52011-06-06 01:16:30 -06002 * parport-to-butterfly adapter
David Brownell2e10c842006-01-11 11:23:49 -08003 *
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.
David Brownell2e10c842006-01-11 11:23:49 -080015 */
David Brownell2e10c842006-01-11 11:23:49 -080016#include <linux/kernel.h>
17#include <linux/init.h>
18#include <linux/delay.h>
Paul Gortmakerd7614de2011-07-03 15:44:29 -040019#include <linux/module.h>
David Brownellda675292007-05-08 00:27:42 -070020#include <linux/device.h>
David Brownell2e10c842006-01-11 11:23:49 -080021#include <linux/parport.h>
22
Al Viro914e2632006-10-18 13:55:46 -040023#include <linux/sched.h>
David Brownell2e10c842006-01-11 11:23:49 -080024#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
David Brownell2e10c842006-01-11 11:23:49 -080040
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
David Brownell2e10c842006-01-11 11:23:49 -080047#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
David Brownell2e10c842006-01-11 11:23:49 -080052/* CONTROL output bits */
53#define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */
David Brownell2e10c842006-01-11 11:23:49 -080054
55
56
57static inline struct butterfly *spidev_to_pp(struct spi_device *spi)
58{
59 return spi->controller_data;
60}
61
David Brownell2e10c842006-01-11 11:23:49 -080062
63struct 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
David Brownell2e10c842006-01-11 11:23:49 -080080static inline void
81setsck(struct spi_device *spi, int is_on)
82{
83 struct butterfly *pp = spidev_to_pp(spi);
84 u8 bit, byte = pp->lastbyte;
85
David Brownell735ce952007-05-08 00:32:13 -070086 bit = spi_sck_bit;
David Brownell2e10c842006-01-11 11:23:49 -080087
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
96static inline void
97setmosi(struct spi_device *spi, int is_on)
98{
99 struct butterfly *pp = spidev_to_pp(spi);
100 u8 bit, byte = pp->lastbyte;
101
David Brownell735ce952007-05-08 00:32:13 -0700102 bit = spi_mosi_bit;
David Brownell2e10c842006-01-11 11:23:49 -0800103
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
112static inline int getmiso(struct spi_device *spi)
113{
114 struct butterfly *pp = spidev_to_pp(spi);
115 int value;
116 u8 bit;
117
David Brownell735ce952007-05-08 00:32:13 -0700118 bit = spi_miso_bit;
David Brownell2e10c842006-01-11 11:23:49 -0800119
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
125static void butterfly_chipselect(struct spi_device *spi, int value)
126{
127 struct butterfly *pp = spidev_to_pp(spi);
128
129 /* set default clock polarity */
David Brownell9c1da3c2006-01-21 13:21:43 -0800130 if (value != BITBANG_CS_INACTIVE)
David Brownell2e10c842006-01-11 11:23:49 -0800131 setsck(spi, spi->mode & SPI_CPOL);
132
David Brownell9c1da3c2006-01-21 13:21:43 -0800133 /* 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 */
David Brownell2e10c842006-01-11 11:23:49 -0800137 if (spi_cs_bit == PARPORT_CONTROL_INIT)
138 value = !value;
139
David Brownell2e10c842006-01-11 11:23:49 -0800140 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
Jingoo Hanac8ed232013-10-14 10:34:24 +0900146#define spidelay(X) do { } while (0)
147/* #define spidelay ndelay */
David Brownell2e10c842006-01-11 11:23:49 -0800148
Grant Likelyca632f52011-06-06 01:16:30 -0600149#include "spi-bitbang-txrx.h"
David Brownell2e10c842006-01-11 11:23:49 -0800150
151static u32
152butterfly_txrx_word_mode0(struct spi_device *spi,
153 unsigned nsecs,
154 u32 word, u8 bits)
155{
Marek Szyprowski04bb2a02010-06-30 14:27:32 -0600156 return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
David Brownell2e10c842006-01-11 11:23:49 -0800157}
158
159/*----------------------------------------------------------------------*/
160
161/* override default partitioning with cmdlinepart */
162static struct mtd_partition partitions[] = { {
David Brownell9c1da3c2006-01-21 13:21:43 -0800163 /* JFFS2 wants partitions of 4*N blocks for this device,
164 * so sectors 0 and 1 can't be partitions by themselves.
165 */
David Brownell2e10c842006-01-11 11:23:49 -0800166
167 /* sector 0 = 8 pages * 264 bytes/page (1 block)
168 * sector 1 = 248 pages * 264 bytes/page
169 */
Jingoo Hanac8ed232013-10-14 10:34:24 +0900170 .name = "bookkeeping", /* 66 KB */
David Brownell2e10c842006-01-11 11:23:49 -0800171 .offset = 0,
172 .size = (8 + 248) * 264,
Jingoo Hanac8ed232013-10-14 10:34:24 +0900173 /* .mask_flags = MTD_WRITEABLE, */
David Brownell2e10c842006-01-11 11:23:49 -0800174}, {
175 /* sector 2 = 256 pages * 264 bytes/page
176 * sectors 3-5 = 512 pages * 264 bytes/page
177 */
Jingoo Hanac8ed232013-10-14 10:34:24 +0900178 .name = "filesystem", /* 462 KB */
David Brownell2e10c842006-01-11 11:23:49 -0800179 .offset = MTDPART_OFS_APPEND,
180 .size = MTDPART_SIZ_FULL,
181} };
182
183static 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 */
191static struct butterfly *butterfly;
192
193static void butterfly_attach(struct parport *p)
194{
195 struct pardevice *pd;
196 int status;
197 struct butterfly *pp;
198 struct spi_master *master;
David Brownellda675292007-05-08 00:27:42 -0700199 struct device *dev = p->physport->dev;
David Brownell2e10c842006-01-11 11:23:49 -0800200
David Brownellda675292007-05-08 00:27:42 -0700201 if (butterfly || !dev)
David Brownell2e10c842006-01-11 11:23:49 -0800202 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
Jingoo Hanac8ed232013-10-14 10:34:24 +0900208 master = spi_alloc_master(dev, sizeof(*pp));
David Brownell2e10c842006-01-11 11:23:49 -0800209 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
Axel Lin94c69f72013-09-10 15:43:41 +0800224 pp->bitbang.master = master;
David Brownell2e10c842006-01-11 11:23:49 -0800225 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
David Brownell735ce952007-05-08 00:32:13 -0700254 * spi_sck_bit clear (CPOL=0)
David Brownell2e10c842006-01-11 11:23:49 -0800255 */
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
David Brownell9c1da3c2006-01-21 13:21:43 -0800273 /* 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.
David Brownell2e10c842006-01-11 11:23:49 -0800276 */
Ben Dooks1fc75472006-05-20 15:00:17 -0700277
David Brownell2e10c842006-01-11 11:23:49 -0800278 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,
Kay Sievers35f74fc2009-01-06 10:44:37 -0800286 dev_name(&pp->dataflash->dev));
David Brownell2e10c842006-01-11 11:23:49 -0800287
David Brownell2e10c842006-01-11 11:23:49 -0800288 pr_info("%s: AVR Butterfly\n", p->name);
289 butterfly = pp;
290 return;
291
292clean2:
293 /* turn off VCC */
294 parport_write_data(pp->port, 0);
295
296 parport_release(pp->pd);
297clean1:
298 parport_unregister_device(pd);
299clean0:
300 (void) spi_master_put(pp->bitbang.master);
301done:
David Brownell2e10c842006-01-11 11:23:49 -0800302 pr_debug("%s: butterfly probe, fail %d\n", p->name, status);
303}
304
305static void butterfly_detach(struct parport *p)
306{
307 struct butterfly *pp;
David Brownell2e10c842006-01-11 11:23:49 -0800308
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
David Brownell9c1da3c2006-01-21 13:21:43 -0800318 /* stop() unregisters child devices too */
Axel Lind9721ae2014-03-29 18:50:12 +0800319 spi_bitbang_stop(&pp->bitbang);
David Brownell2e10c842006-01-11 11:23:49 -0800320
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
David Brownell2e10c842006-01-11 11:23:49 -0800328 (void) spi_master_put(pp->bitbang.master);
David Brownell2e10c842006-01-11 11:23:49 -0800329}
330
331static struct parport_driver butterfly_driver = {
332 .name = "spi_butterfly",
333 .attach = butterfly_attach,
334 .detach = butterfly_detach,
335};
336
337
338static int __init butterfly_init(void)
339{
340 return parport_register_driver(&butterfly_driver);
341}
342device_initcall(butterfly_init);
343
344static void __exit butterfly_exit(void)
345{
346 parport_unregister_driver(&butterfly_driver);
347}
348module_exit(butterfly_exit);
349
David Brownell9c1da3c2006-01-21 13:21:43 -0800350MODULE_DESCRIPTION("Parport Adapter driver for AVR Butterfly");
David Brownell2e10c842006-01-11 11:23:49 -0800351MODULE_LICENSE("GPL");