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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// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for LM70EVAL-LLP board for the LM70 sensor
4 *
5 * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/init.h>
11#include <linux/module.h>
12#include <linux/kernel.h>
13#include <linux/delay.h>
14#include <linux/device.h>
15#include <linux/parport.h>
16#include <linux/sysfs.h>
17#include <linux/workqueue.h>
18
19#include <linux/spi/spi.h>
20#include <linux/spi/spi_bitbang.h>
21
22/*
23 * The LM70 communicates with a host processor using a 3-wire variant of
24 * the SPI/Microwire bus interface. This driver specifically supports an
25 * NS LM70 LLP Evaluation Board, interfacing to a PC using its parallel
26 * port to bitbang an SPI-parport bridge. Accordingly, this is an SPI
27 * master controller driver. The hwmon/lm70 driver is a "SPI protocol
28 * driver", layered on top of this one and usable without the lm70llp.
29 *
30 * Datasheet and Schematic:
31 * The LM70 is a temperature sensor chip from National Semiconductor; its
32 * datasheet is available at http://www.national.com/pf/LM/LM70.html
33 * The schematic for this particular board (the LM70EVAL-LLP) is
34 * available (on page 4) here:
35 * http://www.national.com/appinfo/tempsensors/files/LM70LLPEVALmanual.pdf
36 *
37 * Also see Documentation/spi/spi-lm70llp.rst. The SPI<->parport code here is
38 * (heavily) based on spi-butterfly by David Brownell.
39 *
40 * The LM70 LLP connects to the PC parallel port in the following manner:
41 *
42 * Parallel LM70 LLP
43 * Port Direction JP2 Header
44 * ----------- --------- ------------
45 * D0 2 - -
46 * D1 3 --> V+ 5
47 * D2 4 --> V+ 5
48 * D3 5 --> V+ 5
49 * D4 6 --> V+ 5
50 * D5 7 --> nCS 8
51 * D6 8 --> SCLK 3
52 * D7 9 --> SI/O 5
53 * GND 25 - GND 7
54 * Select 13 <-- SI/O 1
55 *
56 * Note that parport pin 13 actually gets inverted by the transistor
57 * arrangement which lets either the parport or the LM70 drive the
58 * SI/SO signal (see the schematic for details).
59 */
60
61#define DRVNAME "spi-lm70llp"
62
63#define lm70_INIT 0xBE
64#define SIO 0x10
65#define nCS 0x20
66#define SCLK 0x40
67
68/*-------------------------------------------------------------------------*/
69
70struct spi_lm70llp {
71 struct spi_bitbang bitbang;
72 struct parport *port;
73 struct pardevice *pd;
74 struct spi_device *spidev_lm70;
75 struct spi_board_info info;
76 //struct device *dev;
77};
78
79/* REVISIT : ugly global ; provides "exclusive open" facility */
80static struct spi_lm70llp *lm70llp;
81
82/*-------------------------------------------------------------------*/
83
84static inline struct spi_lm70llp *spidev_to_pp(struct spi_device *spi)
85{
86 return spi->controller_data;
87}
88
89/*---------------------- LM70 LLP eval board-specific inlines follow */
90
91/* NOTE: we don't actually need to reread the output values, since they'll
92 * still be what we wrote before. Plus, going through parport builds in
93 * a ~1ms/operation delay; these SPI transfers could easily be faster.
94 */
95
96static inline void deassertCS(struct spi_lm70llp *pp)
97{
98 u8 data = parport_read_data(pp->port);
99
100 data &= ~0x80; /* pull D7/SI-out low while de-asserted */
101 parport_write_data(pp->port, data | nCS);
102}
103
104static inline void assertCS(struct spi_lm70llp *pp)
105{
106 u8 data = parport_read_data(pp->port);
107
108 data |= 0x80; /* pull D7/SI-out high so lm70 drives SO-in */
109 parport_write_data(pp->port, data & ~nCS);
110}
111
112static inline void clkHigh(struct spi_lm70llp *pp)
113{
114 u8 data = parport_read_data(pp->port);
115
116 parport_write_data(pp->port, data | SCLK);
117}
118
119static inline void clkLow(struct spi_lm70llp *pp)
120{
121 u8 data = parport_read_data(pp->port);
122
123 parport_write_data(pp->port, data & ~SCLK);
124}
125
126/*------------------------- SPI-LM70-specific inlines ----------------------*/
127
128static inline void spidelay(unsigned d)
129{
130 udelay(d);
131}
132
133static inline void setsck(struct spi_device *s, int is_on)
134{
135 struct spi_lm70llp *pp = spidev_to_pp(s);
136
137 if (is_on)
138 clkHigh(pp);
139 else
140 clkLow(pp);
141}
142
143static inline void setmosi(struct spi_device *s, int is_on)
144{
145 /* FIXME update D7 ... this way we can put the chip
146 * into shutdown mode and read the manufacturer ID,
147 * but we can't put it back into operational mode.
148 */
149}
150
151/*
152 * getmiso:
153 * Why do we return 0 when the SIO line is high and vice-versa?
154 * The fact is, the lm70 eval board from NS (which this driver drives),
155 * is wired in just such a way : when the lm70's SIO goes high, a transistor
156 * switches it to low reflecting this on the parport (pin 13), and vice-versa.
157 */
158static inline int getmiso(struct spi_device *s)
159{
160 struct spi_lm70llp *pp = spidev_to_pp(s);
161
162 return ((SIO == (parport_read_status(pp->port) & SIO)) ? 0 : 1);
163}
164
165/*--------------------------------------------------------------------*/
166
167#include "spi-bitbang-txrx.h"
168
169static void lm70_chipselect(struct spi_device *spi, int value)
170{
171 struct spi_lm70llp *pp = spidev_to_pp(spi);
172
173 if (value)
174 assertCS(pp);
175 else
176 deassertCS(pp);
177}
178
179/*
180 * Our actual bitbanger routine.
181 */
182static u32 lm70_txrx(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits,
183 unsigned flags)
184{
185 return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
186}
187
188static void spi_lm70llp_attach(struct parport *p)
189{
190 struct pardevice *pd;
191 struct spi_lm70llp *pp;
192 struct spi_master *master;
193 int status;
194 struct pardev_cb lm70llp_cb;
195
196 if (lm70llp) {
197 pr_warn("spi_lm70llp instance already loaded. Aborting.\n");
198 return;
199 }
200
201 /* TODO: this just _assumes_ a lm70 is there ... no probe;
202 * the lm70 driver could verify it, reading the manf ID.
203 */
204
205 master = spi_alloc_master(p->physport->dev, sizeof *pp);
206 if (!master) {
207 status = -ENOMEM;
208 goto out_fail;
209 }
210 pp = spi_master_get_devdata(master);
211
212 /*
213 * SPI and bitbang hookup.
214 */
215 pp->bitbang.master = master;
216 pp->bitbang.chipselect = lm70_chipselect;
217 pp->bitbang.txrx_word[SPI_MODE_0] = lm70_txrx;
218 pp->bitbang.flags = SPI_3WIRE;
219
220 /*
221 * Parport hookup
222 */
223 pp->port = p;
224 memset(&lm70llp_cb, 0, sizeof(lm70llp_cb));
225 lm70llp_cb.private = pp;
226 lm70llp_cb.flags = PARPORT_FLAG_EXCL;
227 pd = parport_register_dev_model(p, DRVNAME, &lm70llp_cb, 0);
228
229 if (!pd) {
230 status = -ENOMEM;
231 goto out_free_master;
232 }
233 pp->pd = pd;
234
235 status = parport_claim(pd);
236 if (status < 0)
237 goto out_parport_unreg;
238
239 /*
240 * Start SPI ...
241 */
242 status = spi_bitbang_start(&pp->bitbang);
243 if (status < 0) {
244 dev_warn(&pd->dev, "spi_bitbang_start failed with status %d\n",
245 status);
246 goto out_off_and_release;
247 }
248
249 /*
250 * The modalias name MUST match the device_driver name
251 * for the bus glue code to match and subsequently bind them.
252 * We are binding to the generic drivers/hwmon/lm70.c device
253 * driver.
254 */
255 strcpy(pp->info.modalias, "lm70");
256 pp->info.max_speed_hz = 6 * 1000 * 1000;
257 pp->info.chip_select = 0;
258 pp->info.mode = SPI_3WIRE | SPI_MODE_0;
259
260 /* power up the chip, and let the LM70 control SI/SO */
261 parport_write_data(pp->port, lm70_INIT);
262
263 /* Enable access to our primary data structure via
264 * the board info's (void *)controller_data.
265 */
266 pp->info.controller_data = pp;
267 pp->spidev_lm70 = spi_new_device(pp->bitbang.master, &pp->info);
268 if (pp->spidev_lm70)
269 dev_dbg(&pp->spidev_lm70->dev, "spidev_lm70 at %s\n",
270 dev_name(&pp->spidev_lm70->dev));
271 else {
272 dev_warn(&pd->dev, "spi_new_device failed\n");
273 status = -ENODEV;
274 goto out_bitbang_stop;
275 }
276 pp->spidev_lm70->bits_per_word = 8;
277
278 lm70llp = pp;
279 return;
280
281out_bitbang_stop:
282 spi_bitbang_stop(&pp->bitbang);
283out_off_and_release:
284 /* power down */
285 parport_write_data(pp->port, 0);
286 mdelay(10);
287 parport_release(pp->pd);
288out_parport_unreg:
289 parport_unregister_device(pd);
290out_free_master:
291 spi_master_put(master);
292out_fail:
293 pr_info("spi_lm70llp probe fail, status %d\n", status);
294}
295
296static void spi_lm70llp_detach(struct parport *p)
297{
298 struct spi_lm70llp *pp;
299
300 if (!lm70llp || lm70llp->port != p)
301 return;
302
303 pp = lm70llp;
304 spi_bitbang_stop(&pp->bitbang);
305
306 /* power down */
307 parport_write_data(pp->port, 0);
308
309 parport_release(pp->pd);
310 parport_unregister_device(pp->pd);
311
312 spi_master_put(pp->bitbang.master);
313
314 lm70llp = NULL;
315}
316
317static struct parport_driver spi_lm70llp_drv = {
318 .name = DRVNAME,
319 .match_port = spi_lm70llp_attach,
320 .detach = spi_lm70llp_detach,
321 .devmodel = true,
322};
323
324static int __init init_spi_lm70llp(void)
325{
326 return parport_register_driver(&spi_lm70llp_drv);
327}
328module_init(init_spi_lm70llp);
329
330static void __exit cleanup_spi_lm70llp(void)
331{
332 parport_unregister_driver(&spi_lm70llp_drv);
333}
334module_exit(cleanup_spi_lm70llp);
335
336MODULE_AUTHOR("Kaiwan N Billimoria <kaiwan@designergraphix.com>");
337MODULE_DESCRIPTION(
338 "Parport adapter for the National Semiconductor LM70 LLP eval board");
339MODULE_LICENSE("GPL");