iicbus.c revision 49195 
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 *	$Id: iicbus.c,v 1.9 1999/05/08 21:59:04 dfr Exp $
27 *
28 */
29
30/*
31 * Autoconfiguration and support routines for the Philips serial I2C bus
32 */
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/kernel.h>
37#include <sys/module.h>
38#include <sys/bus.h>
39
40#include <machine/clock.h>
41
42#include <dev/iicbus/iiconf.h>
43#include <dev/iicbus/iicbus.h>
44
45#include "iicbus_if.h"
46
47#define DEVTOIICBUS(dev) ((struct iicbus_device*)device_get_ivars(dev))
48
49/*
50 * structure used to attach devices to the I2C bus
51 */
52struct iicbus_device {
53	const char *iicd_name;		/* device name */
54	int iicd_class;			/* driver or slave device class */
55	const char *iicd_desc;		/* device descriptor */
56	u_char iicd_addr;		/* address of the device */
57	int iicd_waitack;		/* wait for ack timeout or delay */
58	int iicd_alive;			/* 1 if device found */
59};
60
61/*
62 * Common I2C addresses
63 */
64#define I2C_GENERAL_CALL	0x0
65#define PCF_MASTER_ADDRESS	0xaa
66#define FIRST_SLAVE_ADDR	0x2
67
68#define LAST_SLAVE_ADDR		255
69
70#define IICBUS_UNKNOWN_CLASS	0
71#define IICBUS_DEVICE_CLASS	1
72#define IICBUS_DRIVER_CLASS	2
73
74/*
75 * list of known devices
76 *
77 * XXX only one smb driver should exist for each I2C interface
78 */
79static struct iicbus_device iicbus_children[] = {
80	{ "iicsmb", IICBUS_DRIVER_CLASS, "I2C to SMB bridge" },
81	{ "iic", IICBUS_DRIVER_CLASS, "I2C general purpose I/O" },
82#if 0
83	{ "ic", IICBUS_DEVICE_CLASS, "network interface", PCF_MASTER_ADDRESS },
84#endif
85	{ NULL, 0 }
86};
87
88static devclass_t iicbus_devclass;
89
90/*
91 * Device methods
92 */
93static int iicbus_probe(device_t);
94static int iicbus_attach(device_t);
95static int iicbus_print_child(device_t, device_t);
96static int iicbus_read_ivar(device_t , device_t, int, u_long *);
97static int iicbus_write_ivar(device_t , device_t, int, u_long);
98
99static device_method_t iicbus_methods[] = {
100        /* device interface */
101        DEVMETHOD(device_probe,         iicbus_probe),
102        DEVMETHOD(device_attach,        iicbus_attach),
103        DEVMETHOD(device_detach,        bus_generic_detach),
104        DEVMETHOD(device_shutdown,      bus_generic_shutdown),
105
106        /* bus interface */
107        DEVMETHOD(bus_print_child,      iicbus_print_child),
108        DEVMETHOD(bus_read_ivar,        iicbus_read_ivar),
109        DEVMETHOD(bus_write_ivar,       iicbus_write_ivar),
110
111        { 0, 0 }
112};
113
114static driver_t iicbus_driver = {
115        "iicbus",
116        iicbus_methods,
117        sizeof(struct iicbus_softc),
118};
119
120static int
121iicbus_probe(device_t dev)
122{
123	device_set_desc(dev, "Philips I2C bus");
124
125	return (0);
126}
127
128#if 0
129static int
130iic_probe_device(device_t dev, u_char addr)
131{
132	int count;
133	char byte;
134
135	if ((addr & 1) == 0) {
136		/* is device writable? */
137		if (!iicbus_start(dev, (u_char)addr, 0)) {
138			iicbus_stop(dev);
139			return (1);
140		}
141	} else {
142		/* is device readable? */
143		if (!iicbus_block_read(dev, (u_char)addr, &byte, 1, &count))
144			return (1);
145	}
146
147	return (0);
148}
149#endif
150
151/*
152 * We add all the devices which we know about.
153 * The generic attach routine will attach them if they are alive.
154 */
155static int
156iicbus_attach(device_t dev)
157{
158	struct iicbus_device *iicdev;
159	device_t child;
160
161	iicbus_reset(dev, IIC_FASTEST, 0, NULL);
162
163	/* device probing is meaningless since the bus is supposed to be
164	 * hot-plug. Moreover, some I2C chips do not appreciate random
165	 * accesses like stop after start to fast, reads for less than
166	 * x bytes...
167	 */
168#if 0
169	printf("Probing for devices on iicbus%d:", device_get_unit(dev));
170
171	/* probe any devices */
172	for (addr = FIRST_SLAVE_ADDR; addr <= LAST_SLAVE_ADDR; addr++) {
173		if (iic_probe_device(dev, (u_char)addr)) {
174			printf(" <%x>", addr);
175		}
176	}
177	printf("\n");
178#endif
179
180	/* attach known devices */
181	for (iicdev = iicbus_children; iicdev->iicd_name; iicdev++) {
182		switch (iicdev->iicd_class) {
183		case IICBUS_DEVICE_CLASS:
184			/* check if the devclass exists */
185			if (devclass_find(iicdev->iicd_name))
186				iicdev->iicd_alive = 1;
187			else if (bootverbose)
188				printf("iicbus: %s devclass not found\n",
189					iicdev->iicd_name);
190			break;
191
192		case IICBUS_DRIVER_CLASS:
193			/* check if the devclass exists */
194    			if (devclass_find(iicdev->iicd_name))
195				iicdev->iicd_alive = 1;
196			else if (bootverbose)
197				printf("iicbus: %s devclass not found\n",
198					iicdev->iicd_name);
199			break;
200
201		default:
202			panic("%s: unknown class!", __FUNCTION__);
203		}
204
205		if (iicdev->iicd_alive) {
206			child = device_add_child(dev, iicdev->iicd_name,
207								-1, iicdev);
208			device_set_desc(child, iicdev->iicd_desc);
209		}
210	}
211	bus_generic_attach(dev);
212
213        return (0);
214}
215
216int
217iicbus_generic_intr(device_t dev, int event, char *buf)
218{
219	return (0);
220}
221
222int
223iicbus_null_callback(device_t dev, int index, caddr_t data)
224{
225	return (0);
226}
227
228int
229iicbus_null_repeated_start(device_t dev, u_char addr)
230{
231	return (IIC_ENOTSUPP);
232}
233
234static int
235iicbus_print_child(device_t bus, device_t dev)
236{
237	struct iicbus_device* iicdev = DEVTOIICBUS(dev);
238	int retval = 0;
239
240	retval += bus_print_child_header(bus, dev);
241
242	switch (iicdev->iicd_class) {
243	case IICBUS_DEVICE_CLASS:
244		retval += printf(" on %s addr 0x%x\n",
245				 device_get_nameunit(bus), iicdev->iicd_addr);
246		break;
247
248	case IICBUS_DRIVER_CLASS:
249		retval += bus_print_child_footer(bus, dev);
250		break;
251
252	default:
253		panic("%s: unknown class!\n", __FUNCTION__);
254	}
255
256	return (retval);
257}
258
259static int
260iicbus_read_ivar(device_t bus, device_t dev, int index, u_long* result)
261{
262	struct iicbus_device* iicdev = DEVTOIICBUS(dev);
263
264	switch (index) {
265	case IICBUS_IVAR_ADDR:
266		*result = (u_long)iicdev->iicd_addr;
267		break;
268
269	default:
270		return (ENOENT);
271	}
272
273	return (0);
274}
275
276static int
277iicbus_write_ivar(device_t bus, device_t dev, int index, u_long val)
278{
279	switch (index) {
280	default:
281		return (ENOENT);
282	}
283
284	return (0);
285}
286
287DRIVER_MODULE(iicbus, pcf, iicbus_driver, iicbus_devclass, 0, 0);
288DRIVER_MODULE(iicbus, iicbb, iicbus_driver, iicbus_devclass, 0, 0);
289DRIVER_MODULE(iicbus, bti2c, iicbus_driver, iicbus_devclass, 0, 0);
290