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1/*
2 * Driver for LM70EVAL-LLP board for the LM70 sensor
3 *
4 * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
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
17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19#include <linux/init.h>
20#include <linux/module.h>
21#include <linux/kernel.h>
22#include <linux/delay.h>
23#include <linux/device.h>
24#include <linux/parport.h>
25#include <linux/sysfs.h>
26#include <linux/workqueue.h>
27
28#include <linux/spi/spi.h>
29#include <linux/spi/spi_bitbang.h>
30
31/*
32 * The LM70 communicates with a host processor using a 3-wire variant of
33 * the SPI/Microwire bus interface. This driver specifically supports an
34 * NS LM70 LLP Evaluation Board, interfacing to a PC using its parallel
35 * port to bitbang an SPI-parport bridge. Accordingly, this is an SPI
36 * master controller driver. The hwmon/lm70 driver is a "SPI protocol
37 * driver", layered on top of this one and usable without the lm70llp.
38 *
39 * Datasheet and Schematic:
40 * The LM70 is a temperature sensor chip from National Semiconductor; its
41 * datasheet is available at http://www.national.com/pf/LM/LM70.html
42 * The schematic for this particular board (the LM70EVAL-LLP) is
43 * available (on page 4) here:
44 * http://www.national.com/appinfo/tempsensors/files/LM70LLPEVALmanual.pdf
45 *
46 * Also see Documentation/spi/spi-lm70llp. The SPI<->parport code here is
47 * (heavily) based on spi-butterfly by David Brownell.
48 *
49 * The LM70 LLP connects to the PC parallel port in the following manner:
50 *
51 * Parallel LM70 LLP
52 * Port Direction JP2 Header
53 * ----------- --------- ------------
54 * D0 2 - -
55 * D1 3 --> V+ 5
56 * D2 4 --> V+ 5
57 * D3 5 --> V+ 5
58 * D4 6 --> V+ 5
59 * D5 7 --> nCS 8
60 * D6 8 --> SCLK 3
61 * D7 9 --> SI/O 5
62 * GND 25 - GND 7
63 * Select 13 <-- SI/O 1
64 *
65 * Note that parport pin 13 actually gets inverted by the transistor
66 * arrangement which lets either the parport or the LM70 drive the
67 * SI/SO signal (see the schematic for details).
68 */
69
70#define DRVNAME "spi-lm70llp"
71
72#define lm70_INIT 0xBE
73#define SIO 0x10
74#define nCS 0x20
75#define SCLK 0x40
76
77/*-------------------------------------------------------------------------*/
78
79struct spi_lm70llp {
80 struct spi_bitbang bitbang;
81 struct parport *port;
82 struct pardevice *pd;
83 struct spi_device *spidev_lm70;
84 struct spi_board_info info;
85 //struct device *dev;
86};
87
88/* REVISIT : ugly global ; provides "exclusive open" facility */
89static struct spi_lm70llp *lm70llp;
90
91/*-------------------------------------------------------------------*/
92
93static inline struct spi_lm70llp *spidev_to_pp(struct spi_device *spi)
94{
95 return spi->controller_data;
96}
97
98/*---------------------- LM70 LLP eval board-specific inlines follow */
99
100/* NOTE: we don't actually need to reread the output values, since they'll
101 * still be what we wrote before. Plus, going through parport builds in
102 * a ~1ms/operation delay; these SPI transfers could easily be faster.
103 */
104
105static inline void deassertCS(struct spi_lm70llp *pp)
106{
107 u8 data = parport_read_data(pp->port);
108
109 data &= ~0x80; /* pull D7/SI-out low while de-asserted */
110 parport_write_data(pp->port, data | nCS);
111}
112
113static inline void assertCS(struct spi_lm70llp *pp)
114{
115 u8 data = parport_read_data(pp->port);
116
117 data |= 0x80; /* pull D7/SI-out high so lm70 drives SO-in */
118 parport_write_data(pp->port, data & ~nCS);
119}
120
121static inline void clkHigh(struct spi_lm70llp *pp)
122{
123 u8 data = parport_read_data(pp->port);
124
125 parport_write_data(pp->port, data | SCLK);
126}
127
128static inline void clkLow(struct spi_lm70llp *pp)
129{
130 u8 data = parport_read_data(pp->port);
131
132 parport_write_data(pp->port, data & ~SCLK);
133}
134
135/*------------------------- SPI-LM70-specific inlines ----------------------*/
136
137static inline void spidelay(unsigned d)
138{
139 udelay(d);
140}
141
142static inline void setsck(struct spi_device *s, int is_on)
143{
144 struct spi_lm70llp *pp = spidev_to_pp(s);
145
146 if (is_on)
147 clkHigh(pp);
148 else
149 clkLow(pp);
150}
151
152static inline void setmosi(struct spi_device *s, int is_on)
153{
154 /* FIXME update D7 ... this way we can put the chip
155 * into shutdown mode and read the manufacturer ID,
156 * but we can't put it back into operational mode.
157 */
158}
159
160/*
161 * getmiso:
162 * Why do we return 0 when the SIO line is high and vice-versa?
163 * The fact is, the lm70 eval board from NS (which this driver drives),
164 * is wired in just such a way : when the lm70's SIO goes high, a transistor
165 * switches it to low reflecting this on the parport (pin 13), and vice-versa.
166 */
167static inline int getmiso(struct spi_device *s)
168{
169 struct spi_lm70llp *pp = spidev_to_pp(s);
170
171 return ((SIO == (parport_read_status(pp->port) & SIO)) ? 0 : 1);
172}
173
174/*--------------------------------------------------------------------*/
175
176#include "spi-bitbang-txrx.h"
177
178static void lm70_chipselect(struct spi_device *spi, int value)
179{
180 struct spi_lm70llp *pp = spidev_to_pp(spi);
181
182 if (value)
183 assertCS(pp);
184 else
185 deassertCS(pp);
186}
187
188/*
189 * Our actual bitbanger routine.
190 */
191static u32 lm70_txrx(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
192{
193 return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
194}
195
196static void spi_lm70llp_attach(struct parport *p)
197{
198 struct pardevice *pd;
199 struct spi_lm70llp *pp;
200 struct spi_master *master;
201 int status;
202 struct pardev_cb lm70llp_cb;
203
204 if (lm70llp) {
205 pr_warn("spi_lm70llp instance already loaded. Aborting.\n");
206 return;
207 }
208
209 /* TODO: this just _assumes_ a lm70 is there ... no probe;
210 * the lm70 driver could verify it, reading the manf ID.
211 */
212
213 master = spi_alloc_master(p->physport->dev, sizeof *pp);
214 if (!master) {
215 status = -ENOMEM;
216 goto out_fail;
217 }
218 pp = spi_master_get_devdata(master);
219
220 /*
221 * SPI and bitbang hookup.
222 */
223 pp->bitbang.master = master;
224 pp->bitbang.chipselect = lm70_chipselect;
225 pp->bitbang.txrx_word[SPI_MODE_0] = lm70_txrx;
226 pp->bitbang.flags = SPI_3WIRE;
227
228 /*
229 * Parport hookup
230 */
231 pp->port = p;
232 memset(&lm70llp_cb, 0, sizeof(lm70llp_cb));
233 lm70llp_cb.private = pp;
234 lm70llp_cb.flags = PARPORT_FLAG_EXCL;
235 pd = parport_register_dev_model(p, DRVNAME, &lm70llp_cb, 0);
236
237 if (!pd) {
238 status = -ENOMEM;
239 goto out_free_master;
240 }
241 pp->pd = pd;
242
243 status = parport_claim(pd);
244 if (status < 0)
245 goto out_parport_unreg;
246
247 /*
248 * Start SPI ...
249 */
250 status = spi_bitbang_start(&pp->bitbang);
251 if (status < 0) {
252 dev_warn(&pd->dev, "spi_bitbang_start failed with status %d\n",
253 status);
254 goto out_off_and_release;
255 }
256
257 /*
258 * The modalias name MUST match the device_driver name
259 * for the bus glue code to match and subsequently bind them.
260 * We are binding to the generic drivers/hwmon/lm70.c device
261 * driver.
262 */
263 strcpy(pp->info.modalias, "lm70");
264 pp->info.max_speed_hz = 6 * 1000 * 1000;
265 pp->info.chip_select = 0;
266 pp->info.mode = SPI_3WIRE | SPI_MODE_0;
267
268 /* power up the chip, and let the LM70 control SI/SO */
269 parport_write_data(pp->port, lm70_INIT);
270
271 /* Enable access to our primary data structure via
272 * the board info's (void *)controller_data.
273 */
274 pp->info.controller_data = pp;
275 pp->spidev_lm70 = spi_new_device(pp->bitbang.master, &pp->info);
276 if (pp->spidev_lm70)
277 dev_dbg(&pp->spidev_lm70->dev, "spidev_lm70 at %s\n",
278 dev_name(&pp->spidev_lm70->dev));
279 else {
280 dev_warn(&pd->dev, "spi_new_device failed\n");
281 status = -ENODEV;
282 goto out_bitbang_stop;
283 }
284 pp->spidev_lm70->bits_per_word = 8;
285
286 lm70llp = pp;
287 return;
288
289out_bitbang_stop:
290 spi_bitbang_stop(&pp->bitbang);
291out_off_and_release:
292 /* power down */
293 parport_write_data(pp->port, 0);
294 mdelay(10);
295 parport_release(pp->pd);
296out_parport_unreg:
297 parport_unregister_device(pd);
298out_free_master:
299 spi_master_put(master);
300out_fail:
301 pr_info("spi_lm70llp probe fail, status %d\n", status);
302}
303
304static void spi_lm70llp_detach(struct parport *p)
305{
306 struct spi_lm70llp *pp;
307
308 if (!lm70llp || lm70llp->port != p)
309 return;
310
311 pp = lm70llp;
312 spi_bitbang_stop(&pp->bitbang);
313
314 /* power down */
315 parport_write_data(pp->port, 0);
316
317 parport_release(pp->pd);
318 parport_unregister_device(pp->pd);
319
320 spi_master_put(pp->bitbang.master);
321
322 lm70llp = NULL;
323}
324
325static struct parport_driver spi_lm70llp_drv = {
326 .name = DRVNAME,
327 .match_port = spi_lm70llp_attach,
328 .detach = spi_lm70llp_detach,
329 .devmodel = true,
330};
331
332static int __init init_spi_lm70llp(void)
333{
334 return parport_register_driver(&spi_lm70llp_drv);
335}
336module_init(init_spi_lm70llp);
337
338static void __exit cleanup_spi_lm70llp(void)
339{
340 parport_unregister_driver(&spi_lm70llp_drv);
341}
342module_exit(cleanup_spi_lm70llp);
343
344MODULE_AUTHOR("Kaiwan N Billimoria <kaiwan@designergraphix.com>");
345MODULE_DESCRIPTION(
346 "Parport adapter for the National Semiconductor LM70 LLP eval board");
347MODULE_LICENSE("GPL");
1/*
2 * Driver for LM70EVAL-LLP board for the LM70 sensor
3 *
4 * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
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
21#include <linux/init.h>
22#include <linux/module.h>
23#include <linux/kernel.h>
24#include <linux/delay.h>
25#include <linux/device.h>
26#include <linux/parport.h>
27#include <linux/sysfs.h>
28#include <linux/workqueue.h>
29
30
31#include <linux/spi/spi.h>
32#include <linux/spi/spi_bitbang.h>
33
34
35/*
36 * The LM70 communicates with a host processor using a 3-wire variant of
37 * the SPI/Microwire bus interface. This driver specifically supports an
38 * NS LM70 LLP Evaluation Board, interfacing to a PC using its parallel
39 * port to bitbang an SPI-parport bridge. Accordingly, this is an SPI
40 * master controller driver. The hwmon/lm70 driver is a "SPI protocol
41 * driver", layered on top of this one and usable without the lm70llp.
42 *
43 * Datasheet and Schematic:
44 * The LM70 is a temperature sensor chip from National Semiconductor; its
45 * datasheet is available at http://www.national.com/pf/LM/LM70.html
46 * The schematic for this particular board (the LM70EVAL-LLP) is
47 * available (on page 4) here:
48 * http://www.national.com/appinfo/tempsensors/files/LM70LLPEVALmanual.pdf
49 *
50 * Also see Documentation/spi/spi-lm70llp. The SPI<->parport code here is
51 * (heavily) based on spi-butterfly by David Brownell.
52 *
53 * The LM70 LLP connects to the PC parallel port in the following manner:
54 *
55 * Parallel LM70 LLP
56 * Port Direction JP2 Header
57 * ----------- --------- ------------
58 * D0 2 - -
59 * D1 3 --> V+ 5
60 * D2 4 --> V+ 5
61 * D3 5 --> V+ 5
62 * D4 6 --> V+ 5
63 * D5 7 --> nCS 8
64 * D6 8 --> SCLK 3
65 * D7 9 --> SI/O 5
66 * GND 25 - GND 7
67 * Select 13 <-- SI/O 1
68 *
69 * Note that parport pin 13 actually gets inverted by the transistor
70 * arrangement which lets either the parport or the LM70 drive the
71 * SI/SO signal (see the schematic for details).
72 */
73
74#define DRVNAME "spi-lm70llp"
75
76#define lm70_INIT 0xBE
77#define SIO 0x10
78#define nCS 0x20
79#define SCLK 0x40
80
81/*-------------------------------------------------------------------------*/
82
83struct spi_lm70llp {
84 struct spi_bitbang bitbang;
85 struct parport *port;
86 struct pardevice *pd;
87 struct spi_device *spidev_lm70;
88 struct spi_board_info info;
89 //struct device *dev;
90};
91
92/* REVISIT : ugly global ; provides "exclusive open" facility */
93static struct spi_lm70llp *lm70llp;
94
95
96/*-------------------------------------------------------------------*/
97
98static inline struct spi_lm70llp *spidev_to_pp(struct spi_device *spi)
99{
100 return spi->controller_data;
101}
102
103/*---------------------- LM70 LLP eval board-specific inlines follow */
104
105/* NOTE: we don't actually need to reread the output values, since they'll
106 * still be what we wrote before. Plus, going through parport builds in
107 * a ~1ms/operation delay; these SPI transfers could easily be faster.
108 */
109
110static inline void deassertCS(struct spi_lm70llp *pp)
111{
112 u8 data = parport_read_data(pp->port);
113
114 data &= ~0x80; /* pull D7/SI-out low while de-asserted */
115 parport_write_data(pp->port, data | nCS);
116}
117
118static inline void assertCS(struct spi_lm70llp *pp)
119{
120 u8 data = parport_read_data(pp->port);
121
122 data |= 0x80; /* pull D7/SI-out high so lm70 drives SO-in */
123 parport_write_data(pp->port, data & ~nCS);
124}
125
126static inline void clkHigh(struct spi_lm70llp *pp)
127{
128 u8 data = parport_read_data(pp->port);
129 parport_write_data(pp->port, data | SCLK);
130}
131
132static inline void clkLow(struct spi_lm70llp *pp)
133{
134 u8 data = parport_read_data(pp->port);
135 parport_write_data(pp->port, data & ~SCLK);
136}
137
138/*------------------------- SPI-LM70-specific inlines ----------------------*/
139
140static inline void spidelay(unsigned d)
141{
142 udelay(d);
143}
144
145static inline void setsck(struct spi_device *s, int is_on)
146{
147 struct spi_lm70llp *pp = spidev_to_pp(s);
148
149 if (is_on)
150 clkHigh(pp);
151 else
152 clkLow(pp);
153}
154
155static inline void setmosi(struct spi_device *s, int is_on)
156{
157 /* FIXME update D7 ... this way we can put the chip
158 * into shutdown mode and read the manufacturer ID,
159 * but we can't put it back into operational mode.
160 */
161}
162
163/*
164 * getmiso:
165 * Why do we return 0 when the SIO line is high and vice-versa?
166 * The fact is, the lm70 eval board from NS (which this driver drives),
167 * is wired in just such a way : when the lm70's SIO goes high, a transistor
168 * switches it to low reflecting this on the parport (pin 13), and vice-versa.
169 */
170static inline int getmiso(struct spi_device *s)
171{
172 struct spi_lm70llp *pp = spidev_to_pp(s);
173 return ((SIO == (parport_read_status(pp->port) & SIO)) ? 0 : 1 );
174}
175/*--------------------------------------------------------------------*/
176
177#include "spi-bitbang-txrx.h"
178
179static void lm70_chipselect(struct spi_device *spi, int value)
180{
181 struct spi_lm70llp *pp = spidev_to_pp(spi);
182
183 if (value)
184 assertCS(pp);
185 else
186 deassertCS(pp);
187}
188
189/*
190 * Our actual bitbanger routine.
191 */
192static u32 lm70_txrx(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
193{
194 return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
195}
196
197static void spi_lm70llp_attach(struct parport *p)
198{
199 struct pardevice *pd;
200 struct spi_lm70llp *pp;
201 struct spi_master *master;
202 int status;
203
204 if (lm70llp) {
205 printk(KERN_WARNING
206 "%s: spi_lm70llp instance already loaded. Aborting.\n",
207 DRVNAME);
208 return;
209 }
210
211 /* TODO: this just _assumes_ a lm70 is there ... no probe;
212 * the lm70 driver could verify it, reading the manf ID.
213 */
214
215 master = spi_alloc_master(p->physport->dev, sizeof *pp);
216 if (!master) {
217 status = -ENOMEM;
218 goto out_fail;
219 }
220 pp = spi_master_get_devdata(master);
221
222 master->bus_num = -1; /* dynamic alloc of a bus number */
223 master->num_chipselect = 1;
224
225 /*
226 * SPI and bitbang hookup.
227 */
228 pp->bitbang.master = spi_master_get(master);
229 pp->bitbang.chipselect = lm70_chipselect;
230 pp->bitbang.txrx_word[SPI_MODE_0] = lm70_txrx;
231 pp->bitbang.flags = SPI_3WIRE;
232
233 /*
234 * Parport hookup
235 */
236 pp->port = p;
237 pd = parport_register_device(p, DRVNAME,
238 NULL, NULL, NULL,
239 PARPORT_FLAG_EXCL, pp);
240 if (!pd) {
241 status = -ENOMEM;
242 goto out_free_master;
243 }
244 pp->pd = pd;
245
246 status = parport_claim(pd);
247 if (status < 0)
248 goto out_parport_unreg;
249
250 /*
251 * Start SPI ...
252 */
253 status = spi_bitbang_start(&pp->bitbang);
254 if (status < 0) {
255 printk(KERN_WARNING
256 "%s: spi_bitbang_start failed with status %d\n",
257 DRVNAME, status);
258 goto out_off_and_release;
259 }
260
261 /*
262 * The modalias name MUST match the device_driver name
263 * for the bus glue code to match and subsequently bind them.
264 * We are binding to the generic drivers/hwmon/lm70.c device
265 * driver.
266 */
267 strcpy(pp->info.modalias, "lm70");
268 pp->info.max_speed_hz = 6 * 1000 * 1000;
269 pp->info.chip_select = 0;
270 pp->info.mode = SPI_3WIRE | SPI_MODE_0;
271
272 /* power up the chip, and let the LM70 control SI/SO */
273 parport_write_data(pp->port, lm70_INIT);
274
275 /* Enable access to our primary data structure via
276 * the board info's (void *)controller_data.
277 */
278 pp->info.controller_data = pp;
279 pp->spidev_lm70 = spi_new_device(pp->bitbang.master, &pp->info);
280 if (pp->spidev_lm70)
281 dev_dbg(&pp->spidev_lm70->dev, "spidev_lm70 at %s\n",
282 dev_name(&pp->spidev_lm70->dev));
283 else {
284 printk(KERN_WARNING "%s: spi_new_device failed\n", DRVNAME);
285 status = -ENODEV;
286 goto out_bitbang_stop;
287 }
288 pp->spidev_lm70->bits_per_word = 8;
289
290 lm70llp = pp;
291 return;
292
293out_bitbang_stop:
294 spi_bitbang_stop(&pp->bitbang);
295out_off_and_release:
296 /* power down */
297 parport_write_data(pp->port, 0);
298 mdelay(10);
299 parport_release(pp->pd);
300out_parport_unreg:
301 parport_unregister_device(pd);
302out_free_master:
303 (void) spi_master_put(master);
304out_fail:
305 pr_info("%s: spi_lm70llp probe fail, status %d\n", DRVNAME, status);
306}
307
308static void spi_lm70llp_detach(struct parport *p)
309{
310 struct spi_lm70llp *pp;
311
312 if (!lm70llp || lm70llp->port != p)
313 return;
314
315 pp = lm70llp;
316 spi_bitbang_stop(&pp->bitbang);
317
318 /* power down */
319 parport_write_data(pp->port, 0);
320
321 parport_release(pp->pd);
322 parport_unregister_device(pp->pd);
323
324 (void) spi_master_put(pp->bitbang.master);
325
326 lm70llp = NULL;
327}
328
329
330static struct parport_driver spi_lm70llp_drv = {
331 .name = DRVNAME,
332 .attach = spi_lm70llp_attach,
333 .detach = spi_lm70llp_detach,
334};
335
336static int __init init_spi_lm70llp(void)
337{
338 return parport_register_driver(&spi_lm70llp_drv);
339}
340module_init(init_spi_lm70llp);
341
342static void __exit cleanup_spi_lm70llp(void)
343{
344 parport_unregister_driver(&spi_lm70llp_drv);
345}
346module_exit(cleanup_spi_lm70llp);
347
348MODULE_AUTHOR("Kaiwan N Billimoria <kaiwan@designergraphix.com>");
349MODULE_DESCRIPTION(
350 "Parport adapter for the National Semiconductor LM70 LLP eval board");
351MODULE_LICENSE("GPL");