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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 * host 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_controller *host;
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 host = spi_alloc_host(p->physport->dev, sizeof(*pp));
206 if (!host) {
207 status = -ENOMEM;
208 goto out_fail;
209 }
210 pp = spi_controller_get_devdata(host);
211
212 /*
213 * SPI and bitbang hookup.
214 */
215 pp->bitbang.master = host;
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_host;
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_host:
291 spi_controller_put(host);
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_controller_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};
323module_parport_driver(spi_lm70llp_drv);
324
325MODULE_AUTHOR("Kaiwan N Billimoria <kaiwan@designergraphix.com>");
326MODULE_DESCRIPTION(
327 "Parport adapter for the National Semiconductor LM70 LLP eval board");
328MODULE_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");