xref: /freebsd/sys/dev/smbus/smbus.c (revision 6ef644f5889afbd0f681b08ed1a2f369524af83e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 1998, 2001 Nicolas Souchu
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  *
29  */
30 
31 #include <sys/cdefs.h>
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/bus.h>
35 #include <sys/lock.h>
36 #include <sys/malloc.h>
37 #include <sys/module.h>
38 #include <sys/mutex.h>
39 #include <sys/sbuf.h>
40 
41 #include <dev/smbus/smbconf.h>
42 #include <dev/smbus/smbus.h>
43 
44 #include "smbus_if.h"
45 #include "bus_if.h"
46 
47 struct smbus_ivar
48 {
49 	uint8_t	addr;
50 };
51 
52 /*
53  * Autoconfiguration and support routines for System Management bus
54  */
55 
56 static int
57 smbus_probe(device_t dev)
58 {
59 
60 	device_set_desc(dev, "System Management Bus");
61 
62 	return (0);
63 }
64 
65 static int
66 smbus_attach(device_t dev)
67 {
68 	struct smbus_softc *sc = device_get_softc(dev);
69 
70 	mtx_init(&sc->lock, device_get_nameunit(dev), "smbus", MTX_DEF);
71 	bus_generic_probe(dev);
72 	bus_enumerate_hinted_children(dev);
73 	bus_generic_attach(dev);
74 
75 	return (0);
76 }
77 
78 static int
79 smbus_detach(device_t dev)
80 {
81 	struct smbus_softc *sc = device_get_softc(dev);
82 	int error;
83 
84 	error = bus_generic_detach(dev);
85 	if (error)
86 		return (error);
87 	device_delete_children(dev);
88 	mtx_destroy(&sc->lock);
89 
90 	return (0);
91 }
92 
93 void
94 smbus_generic_intr(device_t dev, u_char devaddr, char low, char high, int err)
95 {
96 }
97 
98 static device_t
99 smbus_add_child(device_t dev, u_int order, const char *name, int unit)
100 {
101 	struct smbus_ivar *devi;
102 	device_t child;
103 
104 	child = device_add_child_ordered(dev, order, name, unit);
105 	if (child == NULL)
106 		return (child);
107 	devi = malloc(sizeof(struct smbus_ivar), M_DEVBUF, M_NOWAIT | M_ZERO);
108 	if (devi == NULL) {
109 		device_delete_child(dev, child);
110 		return (NULL);
111 	}
112 	device_set_ivars(child, devi);
113 	return (child);
114 }
115 
116 static void
117 smbus_hinted_child(device_t bus, const char *dname, int dunit)
118 {
119 	struct smbus_ivar *devi;
120 	device_t child;
121 	int addr;
122 
123 	addr = 0;
124 	resource_int_value(dname, dunit, "addr", &addr);
125 	if (addr > UINT8_MAX) {
126 		device_printf(bus, "ignored incorrect slave address hint 0x%x"
127 		    " for %s%d\n", addr, dname, dunit);
128 		return;
129 	}
130 	child = BUS_ADD_CHILD(bus, SMBUS_ORDER_HINTED, dname, dunit);
131 	if (child == NULL)
132 		return;
133 	devi = device_get_ivars(child);
134 	devi->addr = addr;
135 }
136 
137 static int
138 smbus_child_location(device_t parent, device_t child, struct sbuf *sb)
139 {
140 	struct smbus_ivar *devi;
141 
142 	devi = device_get_ivars(child);
143 	if (devi->addr != 0)
144 		sbuf_printf(sb, "addr=0x%x", devi->addr);
145 	return (0);
146 }
147 
148 static int
149 smbus_print_child(device_t parent, device_t child)
150 {
151 	struct smbus_ivar *devi;
152 	int retval;
153 
154 	devi = device_get_ivars(child);
155 	retval = bus_print_child_header(parent, child);
156 	if (devi->addr != 0)
157 		retval += printf(" at addr 0x%x", devi->addr);
158 	retval += bus_print_child_footer(parent, child);
159 
160 	return (retval);
161 }
162 
163 static int
164 smbus_read_ivar(device_t parent, device_t child, int which, uintptr_t *result)
165 {
166 	struct smbus_ivar *devi;
167 
168 	devi = device_get_ivars(child);
169 	switch (which) {
170 	case SMBUS_IVAR_ADDR:
171 		if (devi->addr != 0)
172 			*result = devi->addr;
173 		else
174 			*result = -1;
175 		break;
176 	default:
177 		return (ENOENT);
178 	}
179 	return (0);
180 }
181 
182 static int
183 smbus_write_ivar(device_t parent, device_t child, int which, uintptr_t value)
184 {
185 	struct smbus_ivar *devi;
186 
187 	devi = device_get_ivars(child);
188 	switch (which) {
189 	case SMBUS_IVAR_ADDR:
190 		/* Allow to set but no change the slave address. */
191 		if (devi->addr != 0)
192 			return (EINVAL);
193 		devi->addr = value;
194 		break;
195 	default:
196 		return (ENOENT);
197 	}
198 	return (0);
199 }
200 
201 static void
202 smbus_probe_nomatch(device_t bus, device_t child)
203 {
204 	struct smbus_ivar *devi = device_get_ivars(child);
205 
206 	/*
207 	 * Ignore (self-identified) devices without a slave address set.
208 	 * For example, smb(4).
209 	 */
210 	if (devi->addr != 0)
211 		device_printf(bus, "<unknown device> at addr %#x\n",
212 		    devi->addr);
213 }
214 
215 /*
216  * Device methods
217  */
218 static device_method_t smbus_methods[] = {
219         /* device interface */
220         DEVMETHOD(device_probe,         smbus_probe),
221         DEVMETHOD(device_attach,        smbus_attach),
222         DEVMETHOD(device_detach,        smbus_detach),
223 
224 	/* bus interface */
225 	DEVMETHOD(bus_add_child,	smbus_add_child),
226 	DEVMETHOD(bus_hinted_child,	smbus_hinted_child),
227 	DEVMETHOD(bus_probe_nomatch,	smbus_probe_nomatch),
228 	DEVMETHOD(bus_child_location,	smbus_child_location),
229 	DEVMETHOD(bus_print_child,	smbus_print_child),
230 	DEVMETHOD(bus_read_ivar,	smbus_read_ivar),
231 	DEVMETHOD(bus_write_ivar,	smbus_write_ivar),
232 
233 	DEVMETHOD_END
234 };
235 
236 driver_t smbus_driver = {
237         "smbus",
238         smbus_methods,
239         sizeof(struct smbus_softc),
240 };
241 
242 MODULE_VERSION(smbus, SMBUS_MODVER);
243