iiconf.c revision 93023 
1/*-
2 * Copyright (c) 1998 Nicolas Souchu
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/dev/iicbus/iiconf.c 93023 2002-03-23 15:49:15Z nsouch $
27 *
28 */
29#include <sys/param.h>
30#include <sys/systm.h>
31#include <sys/module.h>
32#include <sys/bus.h>
33
34#include <dev/iicbus/iiconf.h>
35#include <dev/iicbus/iicbus.h>
36#include "iicbus_if.h"
37
38/*
39 * iicbus_intr()
40 */
41void
42iicbus_intr(device_t bus, int event, char *buf)
43{
44	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
45
46	/* call owner's intr routine */
47	if (sc->owner)
48		IICBUS_INTR(sc->owner, event, buf);
49
50	return;
51}
52
53static int
54iicbus_poll(struct iicbus_softc *sc, int how)
55{
56	int error;
57
58	switch (how) {
59	case (IIC_WAIT | IIC_INTR):
60		error = tsleep(sc, IICPRI|PCATCH, "iicreq", 0);
61		break;
62
63	case (IIC_WAIT | IIC_NOINTR):
64		error = tsleep(sc, IICPRI, "iicreq", 0);
65		break;
66
67	default:
68		return (EWOULDBLOCK);
69		break;
70	}
71
72	return (error);
73}
74
75/*
76 * iicbus_request_bus()
77 *
78 * Allocate the device to perform transfers.
79 *
80 * how	: IIC_WAIT or IIC_DONTWAIT
81 */
82int
83iicbus_request_bus(device_t bus, device_t dev, int how)
84{
85	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
86	int s, error = 0;
87
88	/* first, ask the underlying layers if the request is ok */
89	do {
90		error = IICBUS_CALLBACK(device_get_parent(bus),
91						IIC_REQUEST_BUS, (caddr_t)&how);
92		if (error)
93			error = iicbus_poll(sc, how);
94	} while (error == EWOULDBLOCK);
95
96	while (!error) {
97		s = splhigh();
98		if (sc->owner && sc->owner != dev) {
99			splx(s);
100
101			error = iicbus_poll(sc, how);
102		} else {
103			sc->owner = dev;
104
105			splx(s);
106			return (0);
107		}
108
109		/* free any allocated resource */
110		if (error)
111			IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS,
112					(caddr_t)&how);
113	}
114
115	return (error);
116}
117
118/*
119 * iicbus_release_bus()
120 *
121 * Release the device allocated with iicbus_request_dev()
122 */
123int
124iicbus_release_bus(device_t bus, device_t dev)
125{
126	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
127	int s, error;
128
129	/* first, ask the underlying layers if the release is ok */
130	error = IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS, NULL);
131
132	if (error)
133		return (error);
134
135	s = splhigh();
136	if (sc->owner != dev) {
137		splx(s);
138		return (EACCES);
139	}
140
141	sc->owner = 0;
142	splx(s);
143
144	/* wakeup waiting processes */
145	wakeup(sc);
146
147	return (0);
148}
149
150/*
151 * iicbus_started()
152 *
153 * Test if the iicbus is started by the controller
154 */
155int
156iicbus_started(device_t bus)
157{
158	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
159
160	return (sc->started);
161}
162
163/*
164 * iicbus_start()
165 *
166 * Send start condition to the slave addressed by 'slave'
167 */
168int
169iicbus_start(device_t bus, u_char slave, int timeout)
170{
171	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
172	int error = 0;
173
174	if (sc->started)
175		return (EINVAL);		/* bus already started */
176
177	if (!(error = IICBUS_START(device_get_parent(bus), slave, timeout)))
178		sc->started = slave;
179	else
180		sc->started = 0;
181
182	return (error);
183}
184
185/*
186 * iicbus_repeated_start()
187 *
188 * Send start condition to the slave addressed by 'slave'
189 */
190int
191iicbus_repeated_start(device_t bus, u_char slave, int timeout)
192{
193	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
194	int error = 0;
195
196	if (!sc->started)
197		return (EINVAL);     /* bus should have been already started */
198
199	if (!(error = IICBUS_REPEATED_START(device_get_parent(bus), slave, timeout)))
200		sc->started = slave;
201	else
202		sc->started = 0;
203
204	return (error);
205}
206
207/*
208 * iicbus_stop()
209 *
210 * Send stop condition to the bus
211 */
212int
213iicbus_stop(device_t bus)
214{
215	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
216	int error = 0;
217
218	if (!sc->started)
219		return (EINVAL);		/* bus not started */
220
221	error = IICBUS_STOP(device_get_parent(bus));
222
223	/* refuse any further access */
224	sc->started = 0;
225
226	return (error);
227}
228
229/*
230 * iicbus_write()
231 *
232 * Write a block of data to the slave previously started by
233 * iicbus_start() call
234 */
235int
236iicbus_write(device_t bus, char *buf, int len, int *sent, int timeout)
237{
238	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
239
240	/* a slave must have been started with the appropriate address */
241	if (!sc->started || (sc->started & LSB))
242		return (EINVAL);
243
244	return (IICBUS_WRITE(device_get_parent(bus), buf, len, sent, timeout));
245}
246
247/*
248 * iicbus_read()
249 *
250 * Read a block of data from the slave previously started by
251 * iicbus_read() call
252 */
253int
254iicbus_read(device_t bus, char *buf, int len, int *read, int last, int delay)
255{
256	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
257
258	/* a slave must have been started with the appropriate address */
259	if (!sc->started || !(sc->started & LSB))
260		return (EINVAL);
261
262	return (IICBUS_READ(device_get_parent(bus), buf, len, read, last, delay));
263}
264
265/*
266 * iicbus_write_byte()
267 *
268 * Write a byte to the slave previously started by iicbus_start() call
269 */
270int
271iicbus_write_byte(device_t bus, char byte, int timeout)
272{
273	char data = byte;
274	int sent;
275
276	return (iicbus_write(bus, &data, 1, &sent, timeout));
277}
278
279/*
280 * iicbus_read_byte()
281 *
282 * Read a byte from the slave previously started by iicbus_start() call
283 */
284int
285iicbus_read_byte(device_t bus, char *byte, int timeout)
286{
287	int read;
288
289	return (iicbus_read(bus, byte, 1, &read, IIC_LAST_READ, timeout));
290}
291
292/*
293 * iicbus_block_write()
294 *
295 * Write a block of data to slave ; start/stop protocol managed
296 */
297int
298iicbus_block_write(device_t bus, u_char slave, char *buf, int len, int *sent)
299{
300	u_char addr = slave & ~LSB;
301	int error;
302
303	if ((error = iicbus_start(bus, addr, 0)))
304		return (error);
305
306	error = iicbus_write(bus, buf, len, sent, 0);
307
308	iicbus_stop(bus);
309
310	return (error);
311}
312
313/*
314 * iicbus_block_read()
315 *
316 * Read a block of data from slave ; start/stop protocol managed
317 */
318int
319iicbus_block_read(device_t bus, u_char slave, char *buf, int len, int *read)
320{
321	u_char addr = slave | LSB;
322	int error;
323
324	if ((error = iicbus_start(bus, addr, 0)))
325		return (error);
326
327	error = iicbus_read(bus, buf, len, read, IIC_LAST_READ, 0);
328
329	iicbus_stop(bus);
330
331	return (error);
332}
333