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c942fddf | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2e10c84b | 2 | /* |
ca632f55 | 3 | * parport-to-butterfly adapter |
2e10c84b DB |
4 | * |
5 | * Copyright (C) 2005 David Brownell | |
2e10c84b | 6 | */ |
2e10c84b DB |
7 | #include <linux/kernel.h> |
8 | #include <linux/init.h> | |
9 | #include <linux/delay.h> | |
d7614de4 | 10 | #include <linux/module.h> |
da675296 | 11 | #include <linux/device.h> |
2e10c84b DB |
12 | #include <linux/parport.h> |
13 | ||
914e2637 | 14 | #include <linux/sched.h> |
2e10c84b DB |
15 | #include <linux/spi/spi.h> |
16 | #include <linux/spi/spi_bitbang.h> | |
17 | #include <linux/spi/flash.h> | |
18 | ||
19 | #include <linux/mtd/partitions.h> | |
20 | ||
2e10c84b DB |
21 | /* |
22 | * This uses SPI to talk with an "AVR Butterfly", which is a $US20 card | |
23 | * with a battery powered AVR microcontroller and lots of goodies. You | |
24 | * can use GCC to develop firmware for this. | |
25 | * | |
9cdd273e | 26 | * See Documentation/spi/butterfly.rst for information about how to build |
2e10c84b DB |
27 | * and use this custom parallel port cable. |
28 | */ | |
29 | ||
2e10c84b DB |
30 | /* DATA output bits (pins 2..9 == D0..D7) */ |
31 | #define butterfly_nreset (1 << 1) /* pin 3 */ | |
32 | ||
33 | #define spi_sck_bit (1 << 0) /* pin 2 */ | |
34 | #define spi_mosi_bit (1 << 7) /* pin 9 */ | |
35 | ||
2e10c84b DB |
36 | #define vcc_bits ((1 << 6) | (1 << 5)) /* pins 7, 8 */ |
37 | ||
38 | /* STATUS input bits */ | |
39 | #define spi_miso_bit PARPORT_STATUS_BUSY /* pin 11 */ | |
40 | ||
2e10c84b DB |
41 | /* CONTROL output bits */ |
42 | #define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */ | |
2e10c84b | 43 | |
2e10c84b DB |
44 | static inline struct butterfly *spidev_to_pp(struct spi_device *spi) |
45 | { | |
46 | return spi->controller_data; | |
47 | } | |
48 | ||
2e10c84b DB |
49 | struct butterfly { |
50 | /* REVISIT ... for now, this must be first */ | |
51 | struct spi_bitbang bitbang; | |
52 | ||
53 | struct parport *port; | |
54 | struct pardevice *pd; | |
55 | ||
56 | u8 lastbyte; | |
57 | ||
58 | struct spi_device *dataflash; | |
59 | struct spi_device *butterfly; | |
60 | struct spi_board_info info[2]; | |
61 | ||
62 | }; | |
63 | ||
64 | /*----------------------------------------------------------------------*/ | |
65 | ||
2e10c84b DB |
66 | static inline void |
67 | setsck(struct spi_device *spi, int is_on) | |
68 | { | |
69 | struct butterfly *pp = spidev_to_pp(spi); | |
70 | u8 bit, byte = pp->lastbyte; | |
71 | ||
735ce95e | 72 | bit = spi_sck_bit; |
2e10c84b DB |
73 | |
74 | if (is_on) | |
75 | byte |= bit; | |
76 | else | |
77 | byte &= ~bit; | |
78 | parport_write_data(pp->port, byte); | |
79 | pp->lastbyte = byte; | |
80 | } | |
81 | ||
82 | static inline void | |
83 | setmosi(struct spi_device *spi, int is_on) | |
84 | { | |
85 | struct butterfly *pp = spidev_to_pp(spi); | |
86 | u8 bit, byte = pp->lastbyte; | |
87 | ||
735ce95e | 88 | bit = spi_mosi_bit; |
2e10c84b DB |
89 | |
90 | if (is_on) | |
91 | byte |= bit; | |
92 | else | |
93 | byte &= ~bit; | |
94 | parport_write_data(pp->port, byte); | |
95 | pp->lastbyte = byte; | |
96 | } | |
97 | ||
98 | static inline int getmiso(struct spi_device *spi) | |
99 | { | |
100 | struct butterfly *pp = spidev_to_pp(spi); | |
101 | int value; | |
102 | u8 bit; | |
103 | ||
735ce95e | 104 | bit = spi_miso_bit; |
2e10c84b DB |
105 | |
106 | /* only STATUS_BUSY is NOT negated */ | |
107 | value = !(parport_read_status(pp->port) & bit); | |
108 | return (bit == PARPORT_STATUS_BUSY) ? value : !value; | |
109 | } | |
110 | ||
111 | static void butterfly_chipselect(struct spi_device *spi, int value) | |
112 | { | |
113 | struct butterfly *pp = spidev_to_pp(spi); | |
114 | ||
115 | /* set default clock polarity */ | |
9c1da3cb | 116 | if (value != BITBANG_CS_INACTIVE) |
2e10c84b DB |
117 | setsck(spi, spi->mode & SPI_CPOL); |
118 | ||
9c1da3cb DB |
119 | /* here, value == "activate or not"; |
120 | * most PARPORT_CONTROL_* bits are negated, so we must | |
121 | * morph it to value == "bit value to write in control register" | |
122 | */ | |
2e10c84b DB |
123 | if (spi_cs_bit == PARPORT_CONTROL_INIT) |
124 | value = !value; | |
125 | ||
2e10c84b DB |
126 | parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0); |
127 | } | |
128 | ||
2e10c84b DB |
129 | /* we only needed to implement one mode here, and choose SPI_MODE_0 */ |
130 | ||
ac8ed236 JH |
131 | #define spidelay(X) do { } while (0) |
132 | /* #define spidelay ndelay */ | |
2e10c84b | 133 | |
ca632f55 | 134 | #include "spi-bitbang-txrx.h" |
2e10c84b DB |
135 | |
136 | static u32 | |
e71fec73 | 137 | butterfly_txrx_word_mode0(struct spi_device *spi, unsigned nsecs, u32 word, |
304d3436 | 138 | u8 bits, unsigned flags) |
2e10c84b | 139 | { |
304d3436 | 140 | return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits); |
2e10c84b DB |
141 | } |
142 | ||
143 | /*----------------------------------------------------------------------*/ | |
144 | ||
145 | /* override default partitioning with cmdlinepart */ | |
146 | static struct mtd_partition partitions[] = { { | |
9c1da3cb DB |
147 | /* JFFS2 wants partitions of 4*N blocks for this device, |
148 | * so sectors 0 and 1 can't be partitions by themselves. | |
149 | */ | |
2e10c84b DB |
150 | |
151 | /* sector 0 = 8 pages * 264 bytes/page (1 block) | |
152 | * sector 1 = 248 pages * 264 bytes/page | |
153 | */ | |
ac8ed236 | 154 | .name = "bookkeeping", /* 66 KB */ |
2e10c84b DB |
155 | .offset = 0, |
156 | .size = (8 + 248) * 264, | |
ac8ed236 | 157 | /* .mask_flags = MTD_WRITEABLE, */ |
2e10c84b DB |
158 | }, { |
159 | /* sector 2 = 256 pages * 264 bytes/page | |
160 | * sectors 3-5 = 512 pages * 264 bytes/page | |
161 | */ | |
ac8ed236 | 162 | .name = "filesystem", /* 462 KB */ |
2e10c84b DB |
163 | .offset = MTDPART_OFS_APPEND, |
164 | .size = MTDPART_SIZ_FULL, | |
165 | } }; | |
166 | ||
167 | static struct flash_platform_data flash = { | |
168 | .name = "butterflash", | |
169 | .parts = partitions, | |
170 | .nr_parts = ARRAY_SIZE(partitions), | |
171 | }; | |
172 | ||
2e10c84b DB |
173 | /* REVISIT remove this ugly global and its "only one" limitation */ |
174 | static struct butterfly *butterfly; | |
175 | ||
176 | static void butterfly_attach(struct parport *p) | |
177 | { | |
178 | struct pardevice *pd; | |
179 | int status; | |
180 | struct butterfly *pp; | |
5a59b9a1 | 181 | struct spi_controller *host; |
da675296 | 182 | struct device *dev = p->physport->dev; |
1d3029cc | 183 | struct pardev_cb butterfly_cb; |
2e10c84b | 184 | |
da675296 | 185 | if (butterfly || !dev) |
2e10c84b DB |
186 | return; |
187 | ||
188 | /* REVISIT: this just _assumes_ a butterfly is there ... no probe, | |
189 | * and no way to be selective about what it binds to. | |
190 | */ | |
191 | ||
5a59b9a1 YY |
192 | host = spi_alloc_host(dev, sizeof(*pp)); |
193 | if (!host) { | |
2e10c84b DB |
194 | status = -ENOMEM; |
195 | goto done; | |
196 | } | |
5a59b9a1 | 197 | pp = spi_controller_get_devdata(host); |
2e10c84b DB |
198 | |
199 | /* | |
200 | * SPI and bitbang hookup | |
201 | * | |
202 | * use default setup(), cleanup(), and transfer() methods; and | |
203 | * only bother implementing mode 0. Start it later. | |
204 | */ | |
5a59b9a1 YY |
205 | host->bus_num = 42; |
206 | host->num_chipselect = 2; | |
2e10c84b | 207 | |
22592331 | 208 | pp->bitbang.ctlr = host; |
2e10c84b DB |
209 | pp->bitbang.chipselect = butterfly_chipselect; |
210 | pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0; | |
211 | ||
212 | /* | |
213 | * parport hookup | |
214 | */ | |
215 | pp->port = p; | |
1d3029cc SM |
216 | memset(&butterfly_cb, 0, sizeof(butterfly_cb)); |
217 | butterfly_cb.private = pp; | |
218 | pd = parport_register_dev_model(p, "spi_butterfly", &butterfly_cb, 0); | |
2e10c84b DB |
219 | if (!pd) { |
220 | status = -ENOMEM; | |
221 | goto clean0; | |
222 | } | |
223 | pp->pd = pd; | |
224 | ||
225 | status = parport_claim(pd); | |
226 | if (status < 0) | |
227 | goto clean1; | |
228 | ||
229 | /* | |
230 | * Butterfly reset, powerup, run firmware | |
231 | */ | |
232 | pr_debug("%s: powerup/reset Butterfly\n", p->name); | |
233 | ||
234 | /* nCS for dataflash (this bit is inverted on output) */ | |
235 | parport_frob_control(pp->port, spi_cs_bit, 0); | |
236 | ||
237 | /* stabilize power with chip in reset (nRESET), and | |
735ce95e | 238 | * spi_sck_bit clear (CPOL=0) |
2e10c84b DB |
239 | */ |
240 | pp->lastbyte |= vcc_bits; | |
241 | parport_write_data(pp->port, pp->lastbyte); | |
242 | msleep(5); | |
243 | ||
244 | /* take it out of reset; assume long reset delay */ | |
245 | pp->lastbyte |= butterfly_nreset; | |
246 | parport_write_data(pp->port, pp->lastbyte); | |
247 | msleep(100); | |
248 | ||
2e10c84b DB |
249 | /* |
250 | * Start SPI ... for now, hide that we're two physical busses. | |
251 | */ | |
252 | status = spi_bitbang_start(&pp->bitbang); | |
253 | if (status < 0) | |
254 | goto clean2; | |
255 | ||
9c1da3cb DB |
256 | /* Bus 1 lets us talk to at45db041b (firmware disables AVR SPI), AVR |
257 | * (firmware resets at45, acts as spi slave) or neither (we ignore | |
258 | * both, AVR uses AT45). Here we expect firmware for the first option. | |
2e10c84b | 259 | */ |
1fc7547d | 260 | |
2e10c84b DB |
261 | pp->info[0].max_speed_hz = 15 * 1000 * 1000; |
262 | strcpy(pp->info[0].modalias, "mtd_dataflash"); | |
263 | pp->info[0].platform_data = &flash; | |
264 | pp->info[0].chip_select = 1; | |
265 | pp->info[0].controller_data = pp; | |
22592331 | 266 | pp->dataflash = spi_new_device(pp->bitbang.ctlr, &pp->info[0]); |
2e10c84b DB |
267 | if (pp->dataflash) |
268 | pr_debug("%s: dataflash at %s\n", p->name, | |
e71fec73 | 269 | dev_name(&pp->dataflash->dev)); |
2e10c84b | 270 | |
2e10c84b DB |
271 | pr_info("%s: AVR Butterfly\n", p->name); |
272 | butterfly = pp; | |
273 | return; | |
274 | ||
275 | clean2: | |
276 | /* turn off VCC */ | |
277 | parport_write_data(pp->port, 0); | |
278 | ||
279 | parport_release(pp->pd); | |
280 | clean1: | |
281 | parport_unregister_device(pd); | |
282 | clean0: | |
5a59b9a1 | 283 | spi_controller_put(host); |
2e10c84b | 284 | done: |
2e10c84b DB |
285 | pr_debug("%s: butterfly probe, fail %d\n", p->name, status); |
286 | } | |
287 | ||
288 | static void butterfly_detach(struct parport *p) | |
289 | { | |
290 | struct butterfly *pp; | |
2e10c84b DB |
291 | |
292 | /* FIXME this global is ugly ... but, how to quickly get from | |
293 | * the parport to the "struct butterfly" associated with it? | |
294 | * "old school" driver-internal device lists? | |
295 | */ | |
296 | if (!butterfly || butterfly->port != p) | |
297 | return; | |
298 | pp = butterfly; | |
299 | butterfly = NULL; | |
300 | ||
9c1da3cb | 301 | /* stop() unregisters child devices too */ |
d9721ae1 | 302 | spi_bitbang_stop(&pp->bitbang); |
2e10c84b DB |
303 | |
304 | /* turn off VCC */ | |
305 | parport_write_data(pp->port, 0); | |
306 | msleep(10); | |
307 | ||
308 | parport_release(pp->pd); | |
309 | parport_unregister_device(pp->pd); | |
310 | ||
22592331 | 311 | spi_controller_put(pp->bitbang.ctlr); |
2e10c84b DB |
312 | } |
313 | ||
314 | static struct parport_driver butterfly_driver = { | |
315 | .name = "spi_butterfly", | |
1d3029cc | 316 | .match_port = butterfly_attach, |
2e10c84b DB |
317 | .detach = butterfly_detach, |
318 | }; | |
8c7e98f7 | 319 | module_parport_driver(butterfly_driver); |
2e10c84b | 320 | |
9c1da3cb | 321 | MODULE_DESCRIPTION("Parport Adapter driver for AVR Butterfly"); |
2e10c84b | 322 | MODULE_LICENSE("GPL"); |