1c942fddfSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later
2ca632f55SGrant Likely /*
3ca632f55SGrant Likely * parport-to-butterfly adapter
4ca632f55SGrant Likely *
5ca632f55SGrant Likely * Copyright (C) 2005 David Brownell
6ca632f55SGrant Likely */
7ca632f55SGrant Likely #include <linux/kernel.h>
8ca632f55SGrant Likely #include <linux/init.h>
9ca632f55SGrant Likely #include <linux/delay.h>
10d7614de4SPaul Gortmaker #include <linux/module.h>
11ca632f55SGrant Likely #include <linux/device.h>
12ca632f55SGrant Likely #include <linux/parport.h>
13ca632f55SGrant Likely
14ca632f55SGrant Likely #include <linux/sched.h>
15ca632f55SGrant Likely #include <linux/spi/spi.h>
16ca632f55SGrant Likely #include <linux/spi/spi_bitbang.h>
17ca632f55SGrant Likely #include <linux/spi/flash.h>
18ca632f55SGrant Likely
19ca632f55SGrant Likely #include <linux/mtd/partitions.h>
20ca632f55SGrant Likely
21ca632f55SGrant Likely /*
22ca632f55SGrant Likely * This uses SPI to talk with an "AVR Butterfly", which is a $US20 card
23ca632f55SGrant Likely * with a battery powered AVR microcontroller and lots of goodies. You
24ca632f55SGrant Likely * can use GCC to develop firmware for this.
25ca632f55SGrant Likely *
269cdd273eSMauro Carvalho Chehab * See Documentation/spi/butterfly.rst for information about how to build
27ca632f55SGrant Likely * and use this custom parallel port cable.
28ca632f55SGrant Likely */
29ca632f55SGrant Likely
30ca632f55SGrant Likely /* DATA output bits (pins 2..9 == D0..D7) */
31ca632f55SGrant Likely #define butterfly_nreset (1 << 1) /* pin 3 */
32ca632f55SGrant Likely
33ca632f55SGrant Likely #define spi_sck_bit (1 << 0) /* pin 2 */
34ca632f55SGrant Likely #define spi_mosi_bit (1 << 7) /* pin 9 */
35ca632f55SGrant Likely
36ca632f55SGrant Likely #define vcc_bits ((1 << 6) | (1 << 5)) /* pins 7, 8 */
37ca632f55SGrant Likely
38ca632f55SGrant Likely /* STATUS input bits */
39ca632f55SGrant Likely #define spi_miso_bit PARPORT_STATUS_BUSY /* pin 11 */
40ca632f55SGrant Likely
41ca632f55SGrant Likely /* CONTROL output bits */
42ca632f55SGrant Likely #define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */
43ca632f55SGrant Likely
spidev_to_pp(struct spi_device * spi)44ca632f55SGrant Likely static inline struct butterfly *spidev_to_pp(struct spi_device *spi)
45ca632f55SGrant Likely {
46ca632f55SGrant Likely return spi->controller_data;
47ca632f55SGrant Likely }
48ca632f55SGrant Likely
49ca632f55SGrant Likely struct butterfly {
50ca632f55SGrant Likely /* REVISIT ... for now, this must be first */
51ca632f55SGrant Likely struct spi_bitbang bitbang;
52ca632f55SGrant Likely
53ca632f55SGrant Likely struct parport *port;
54ca632f55SGrant Likely struct pardevice *pd;
55ca632f55SGrant Likely
56ca632f55SGrant Likely u8 lastbyte;
57ca632f55SGrant Likely
58ca632f55SGrant Likely struct spi_device *dataflash;
59ca632f55SGrant Likely struct spi_device *butterfly;
60ca632f55SGrant Likely struct spi_board_info info[2];
61ca632f55SGrant Likely
62ca632f55SGrant Likely };
63ca632f55SGrant Likely
64ca632f55SGrant Likely /*----------------------------------------------------------------------*/
65ca632f55SGrant Likely
66ca632f55SGrant Likely static inline void
setsck(struct spi_device * spi,int is_on)67ca632f55SGrant Likely setsck(struct spi_device *spi, int is_on)
68ca632f55SGrant Likely {
69ca632f55SGrant Likely struct butterfly *pp = spidev_to_pp(spi);
70ca632f55SGrant Likely u8 bit, byte = pp->lastbyte;
71ca632f55SGrant Likely
72ca632f55SGrant Likely bit = spi_sck_bit;
73ca632f55SGrant Likely
74ca632f55SGrant Likely if (is_on)
75ca632f55SGrant Likely byte |= bit;
76ca632f55SGrant Likely else
77ca632f55SGrant Likely byte &= ~bit;
78ca632f55SGrant Likely parport_write_data(pp->port, byte);
79ca632f55SGrant Likely pp->lastbyte = byte;
80ca632f55SGrant Likely }
81ca632f55SGrant Likely
82ca632f55SGrant Likely static inline void
setmosi(struct spi_device * spi,int is_on)83ca632f55SGrant Likely setmosi(struct spi_device *spi, int is_on)
84ca632f55SGrant Likely {
85ca632f55SGrant Likely struct butterfly *pp = spidev_to_pp(spi);
86ca632f55SGrant Likely u8 bit, byte = pp->lastbyte;
87ca632f55SGrant Likely
88ca632f55SGrant Likely bit = spi_mosi_bit;
89ca632f55SGrant Likely
90ca632f55SGrant Likely if (is_on)
91ca632f55SGrant Likely byte |= bit;
92ca632f55SGrant Likely else
93ca632f55SGrant Likely byte &= ~bit;
94ca632f55SGrant Likely parport_write_data(pp->port, byte);
95ca632f55SGrant Likely pp->lastbyte = byte;
96ca632f55SGrant Likely }
97ca632f55SGrant Likely
getmiso(struct spi_device * spi)98ca632f55SGrant Likely static inline int getmiso(struct spi_device *spi)
99ca632f55SGrant Likely {
100ca632f55SGrant Likely struct butterfly *pp = spidev_to_pp(spi);
101ca632f55SGrant Likely int value;
102ca632f55SGrant Likely u8 bit;
103ca632f55SGrant Likely
104ca632f55SGrant Likely bit = spi_miso_bit;
105ca632f55SGrant Likely
106ca632f55SGrant Likely /* only STATUS_BUSY is NOT negated */
107ca632f55SGrant Likely value = !(parport_read_status(pp->port) & bit);
108ca632f55SGrant Likely return (bit == PARPORT_STATUS_BUSY) ? value : !value;
109ca632f55SGrant Likely }
110ca632f55SGrant Likely
butterfly_chipselect(struct spi_device * spi,int value)111ca632f55SGrant Likely static void butterfly_chipselect(struct spi_device *spi, int value)
112ca632f55SGrant Likely {
113ca632f55SGrant Likely struct butterfly *pp = spidev_to_pp(spi);
114ca632f55SGrant Likely
115ca632f55SGrant Likely /* set default clock polarity */
116ca632f55SGrant Likely if (value != BITBANG_CS_INACTIVE)
117ca632f55SGrant Likely setsck(spi, spi->mode & SPI_CPOL);
118ca632f55SGrant Likely
119ca632f55SGrant Likely /* here, value == "activate or not";
120ca632f55SGrant Likely * most PARPORT_CONTROL_* bits are negated, so we must
121ca632f55SGrant Likely * morph it to value == "bit value to write in control register"
122ca632f55SGrant Likely */
123ca632f55SGrant Likely if (spi_cs_bit == PARPORT_CONTROL_INIT)
124ca632f55SGrant Likely value = !value;
125ca632f55SGrant Likely
126ca632f55SGrant Likely parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0);
127ca632f55SGrant Likely }
128ca632f55SGrant Likely
129ca632f55SGrant Likely /* we only needed to implement one mode here, and choose SPI_MODE_0 */
130ca632f55SGrant Likely
131ca632f55SGrant Likely #define spidelay(X) do { } while (0)
132ac8ed236SJingoo Han /* #define spidelay ndelay */
133ca632f55SGrant Likely
134ca632f55SGrant Likely #include "spi-bitbang-txrx.h"
135ca632f55SGrant Likely
136ca632f55SGrant Likely static u32
butterfly_txrx_word_mode0(struct spi_device * spi,unsigned nsecs,u32 word,u8 bits,unsigned flags)137e71fec73SSudip Mukherjee butterfly_txrx_word_mode0(struct spi_device *spi, unsigned nsecs, u32 word,
138304d3436SLorenzo Bianconi u8 bits, unsigned flags)
139ca632f55SGrant Likely {
140304d3436SLorenzo Bianconi return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
141ca632f55SGrant Likely }
142ca632f55SGrant Likely
143ca632f55SGrant Likely /*----------------------------------------------------------------------*/
144ca632f55SGrant Likely
145ca632f55SGrant Likely /* override default partitioning with cmdlinepart */
146ca632f55SGrant Likely static struct mtd_partition partitions[] = { {
147ca632f55SGrant Likely /* JFFS2 wants partitions of 4*N blocks for this device,
148ca632f55SGrant Likely * so sectors 0 and 1 can't be partitions by themselves.
149ca632f55SGrant Likely */
150ca632f55SGrant Likely
151ca632f55SGrant Likely /* sector 0 = 8 pages * 264 bytes/page (1 block)
152ca632f55SGrant Likely * sector 1 = 248 pages * 264 bytes/page
153ca632f55SGrant Likely */
154ac8ed236SJingoo Han .name = "bookkeeping", /* 66 KB */
155ca632f55SGrant Likely .offset = 0,
156ca632f55SGrant Likely .size = (8 + 248) * 264,
157ac8ed236SJingoo Han /* .mask_flags = MTD_WRITEABLE, */
158ca632f55SGrant Likely }, {
159ca632f55SGrant Likely /* sector 2 = 256 pages * 264 bytes/page
160ca632f55SGrant Likely * sectors 3-5 = 512 pages * 264 bytes/page
161ca632f55SGrant Likely */
162ac8ed236SJingoo Han .name = "filesystem", /* 462 KB */
163ca632f55SGrant Likely .offset = MTDPART_OFS_APPEND,
164ca632f55SGrant Likely .size = MTDPART_SIZ_FULL,
165ca632f55SGrant Likely } };
166ca632f55SGrant Likely
167ca632f55SGrant Likely static struct flash_platform_data flash = {
168ca632f55SGrant Likely .name = "butterflash",
169ca632f55SGrant Likely .parts = partitions,
170ca632f55SGrant Likely .nr_parts = ARRAY_SIZE(partitions),
171ca632f55SGrant Likely };
172ca632f55SGrant Likely
173ca632f55SGrant Likely /* REVISIT remove this ugly global and its "only one" limitation */
174ca632f55SGrant Likely static struct butterfly *butterfly;
175ca632f55SGrant Likely
butterfly_attach(struct parport * p)176ca632f55SGrant Likely static void butterfly_attach(struct parport *p)
177ca632f55SGrant Likely {
178ca632f55SGrant Likely struct pardevice *pd;
179ca632f55SGrant Likely int status;
180ca632f55SGrant Likely struct butterfly *pp;
181*5a59b9a1SYang Yingliang struct spi_controller *host;
182ca632f55SGrant Likely struct device *dev = p->physport->dev;
1831d3029ccSSudip Mukherjee struct pardev_cb butterfly_cb;
184ca632f55SGrant Likely
185ca632f55SGrant Likely if (butterfly || !dev)
186ca632f55SGrant Likely return;
187ca632f55SGrant Likely
188ca632f55SGrant Likely /* REVISIT: this just _assumes_ a butterfly is there ... no probe,
189ca632f55SGrant Likely * and no way to be selective about what it binds to.
190ca632f55SGrant Likely */
191ca632f55SGrant Likely
192*5a59b9a1SYang Yingliang host = spi_alloc_host(dev, sizeof(*pp));
193*5a59b9a1SYang Yingliang if (!host) {
194ca632f55SGrant Likely status = -ENOMEM;
195ca632f55SGrant Likely goto done;
196ca632f55SGrant Likely }
197*5a59b9a1SYang Yingliang pp = spi_controller_get_devdata(host);
198ca632f55SGrant Likely
199ca632f55SGrant Likely /*
200ca632f55SGrant Likely * SPI and bitbang hookup
201ca632f55SGrant Likely *
202ca632f55SGrant Likely * use default setup(), cleanup(), and transfer() methods; and
203ca632f55SGrant Likely * only bother implementing mode 0. Start it later.
204ca632f55SGrant Likely */
205*5a59b9a1SYang Yingliang host->bus_num = 42;
206*5a59b9a1SYang Yingliang host->num_chipselect = 2;
207ca632f55SGrant Likely
208*5a59b9a1SYang Yingliang pp->bitbang.master = host;
209ca632f55SGrant Likely pp->bitbang.chipselect = butterfly_chipselect;
210ca632f55SGrant Likely pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0;
211ca632f55SGrant Likely
212ca632f55SGrant Likely /*
213ca632f55SGrant Likely * parport hookup
214ca632f55SGrant Likely */
215ca632f55SGrant Likely pp->port = p;
2161d3029ccSSudip Mukherjee memset(&butterfly_cb, 0, sizeof(butterfly_cb));
2171d3029ccSSudip Mukherjee butterfly_cb.private = pp;
2181d3029ccSSudip Mukherjee pd = parport_register_dev_model(p, "spi_butterfly", &butterfly_cb, 0);
219ca632f55SGrant Likely if (!pd) {
220ca632f55SGrant Likely status = -ENOMEM;
221ca632f55SGrant Likely goto clean0;
222ca632f55SGrant Likely }
223ca632f55SGrant Likely pp->pd = pd;
224ca632f55SGrant Likely
225ca632f55SGrant Likely status = parport_claim(pd);
226ca632f55SGrant Likely if (status < 0)
227ca632f55SGrant Likely goto clean1;
228ca632f55SGrant Likely
229ca632f55SGrant Likely /*
230ca632f55SGrant Likely * Butterfly reset, powerup, run firmware
231ca632f55SGrant Likely */
232ca632f55SGrant Likely pr_debug("%s: powerup/reset Butterfly\n", p->name);
233ca632f55SGrant Likely
234ca632f55SGrant Likely /* nCS for dataflash (this bit is inverted on output) */
235ca632f55SGrant Likely parport_frob_control(pp->port, spi_cs_bit, 0);
236ca632f55SGrant Likely
237ca632f55SGrant Likely /* stabilize power with chip in reset (nRESET), and
238ca632f55SGrant Likely * spi_sck_bit clear (CPOL=0)
239ca632f55SGrant Likely */
240ca632f55SGrant Likely pp->lastbyte |= vcc_bits;
241ca632f55SGrant Likely parport_write_data(pp->port, pp->lastbyte);
242ca632f55SGrant Likely msleep(5);
243ca632f55SGrant Likely
244ca632f55SGrant Likely /* take it out of reset; assume long reset delay */
245ca632f55SGrant Likely pp->lastbyte |= butterfly_nreset;
246ca632f55SGrant Likely parport_write_data(pp->port, pp->lastbyte);
247ca632f55SGrant Likely msleep(100);
248ca632f55SGrant Likely
249ca632f55SGrant Likely /*
250ca632f55SGrant Likely * Start SPI ... for now, hide that we're two physical busses.
251ca632f55SGrant Likely */
252ca632f55SGrant Likely status = spi_bitbang_start(&pp->bitbang);
253ca632f55SGrant Likely if (status < 0)
254ca632f55SGrant Likely goto clean2;
255ca632f55SGrant Likely
256ca632f55SGrant Likely /* Bus 1 lets us talk to at45db041b (firmware disables AVR SPI), AVR
257ca632f55SGrant Likely * (firmware resets at45, acts as spi slave) or neither (we ignore
258ca632f55SGrant Likely * both, AVR uses AT45). Here we expect firmware for the first option.
259ca632f55SGrant Likely */
260ca632f55SGrant Likely
261ca632f55SGrant Likely pp->info[0].max_speed_hz = 15 * 1000 * 1000;
262ca632f55SGrant Likely strcpy(pp->info[0].modalias, "mtd_dataflash");
263ca632f55SGrant Likely pp->info[0].platform_data = &flash;
264ca632f55SGrant Likely pp->info[0].chip_select = 1;
265ca632f55SGrant Likely pp->info[0].controller_data = pp;
266ca632f55SGrant Likely pp->dataflash = spi_new_device(pp->bitbang.master, &pp->info[0]);
267ca632f55SGrant Likely if (pp->dataflash)
268ca632f55SGrant Likely pr_debug("%s: dataflash at %s\n", p->name,
269ca632f55SGrant Likely dev_name(&pp->dataflash->dev));
270ca632f55SGrant Likely
271ca632f55SGrant Likely pr_info("%s: AVR Butterfly\n", p->name);
272ca632f55SGrant Likely butterfly = pp;
273ca632f55SGrant Likely return;
274ca632f55SGrant Likely
275ca632f55SGrant Likely clean2:
276ca632f55SGrant Likely /* turn off VCC */
277ca632f55SGrant Likely parport_write_data(pp->port, 0);
278ca632f55SGrant Likely
279ca632f55SGrant Likely parport_release(pp->pd);
280ca632f55SGrant Likely clean1:
281ca632f55SGrant Likely parport_unregister_device(pd);
282ca632f55SGrant Likely clean0:
283*5a59b9a1SYang Yingliang spi_controller_put(host);
284ca632f55SGrant Likely done:
285ca632f55SGrant Likely pr_debug("%s: butterfly probe, fail %d\n", p->name, status);
286ca632f55SGrant Likely }
287ca632f55SGrant Likely
butterfly_detach(struct parport * p)288ca632f55SGrant Likely static void butterfly_detach(struct parport *p)
289ca632f55SGrant Likely {
290ca632f55SGrant Likely struct butterfly *pp;
291ca632f55SGrant Likely
292ca632f55SGrant Likely /* FIXME this global is ugly ... but, how to quickly get from
293ca632f55SGrant Likely * the parport to the "struct butterfly" associated with it?
294ca632f55SGrant Likely * "old school" driver-internal device lists?
295ca632f55SGrant Likely */
296ca632f55SGrant Likely if (!butterfly || butterfly->port != p)
297ca632f55SGrant Likely return;
298ca632f55SGrant Likely pp = butterfly;
299ca632f55SGrant Likely butterfly = NULL;
300ca632f55SGrant Likely
301ca632f55SGrant Likely /* stop() unregisters child devices too */
302d9721ae1SAxel Lin spi_bitbang_stop(&pp->bitbang);
303ca632f55SGrant Likely
304ca632f55SGrant Likely /* turn off VCC */
305ca632f55SGrant Likely parport_write_data(pp->port, 0);
306ca632f55SGrant Likely msleep(10);
307ca632f55SGrant Likely
308ca632f55SGrant Likely parport_release(pp->pd);
309ca632f55SGrant Likely parport_unregister_device(pp->pd);
310ca632f55SGrant Likely
311*5a59b9a1SYang Yingliang spi_controller_put(pp->bitbang.master);
312ca632f55SGrant Likely }
313ca632f55SGrant Likely
314ca632f55SGrant Likely static struct parport_driver butterfly_driver = {
315ca632f55SGrant Likely .name = "spi_butterfly",
3161d3029ccSSudip Mukherjee .match_port = butterfly_attach,
317ca632f55SGrant Likely .detach = butterfly_detach,
3181d3029ccSSudip Mukherjee .devmodel = true,
319ca632f55SGrant Likely };
3208c7e98f7SAndy Shevchenko module_parport_driver(butterfly_driver);
321ca632f55SGrant Likely
322ca632f55SGrant Likely MODULE_DESCRIPTION("Parport Adapter driver for AVR Butterfly");
323ca632f55SGrant Likely MODULE_LICENSE("GPL");
324