1 /*-
2 * Copyright (c) 1998, 2001 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
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
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/lock.h>
38 #include <sys/malloc.h>
39 #include <sys/module.h>
40 #include <sys/mutex.h>
41 #include <sys/sysctl.h>
42 #include <sys/bus.h>
43
44 #include <dev/iicbus/iiconf.h>
45 #include <dev/iicbus/iicbus.h>
46
47 #include "iicbus_if.h"
48
49 /* See comments below for why auto-scanning is a bad idea. */
50 #define SCAN_IICBUS 0
51
52 static int
iicbus_probe(device_t dev)53 iicbus_probe(device_t dev)
54 {
55
56 device_set_desc(dev, "Philips I2C bus");
57
58 /* Allow other subclasses to override this driver. */
59 return (BUS_PROBE_GENERIC);
60 }
61
62 #if SCAN_IICBUS
63 static int
iic_probe_device(device_t dev,u_char addr)64 iic_probe_device(device_t dev, u_char addr)
65 {
66 int count;
67 char byte;
68
69 if ((addr & 1) == 0) {
70 /* is device writable? */
71 if (!iicbus_start(dev, (u_char)addr, 0)) {
72 iicbus_stop(dev);
73 return (1);
74 }
75 } else {
76 /* is device readable? */
77 if (!iicbus_block_read(dev, (u_char)addr, &byte, 1, &count))
78 return (1);
79 }
80
81 return (0);
82 }
83 #endif
84
85 /*
86 * We add all the devices which we know about.
87 * The generic attach routine will attach them if they are alive.
88 */
89 static int
iicbus_attach(device_t dev)90 iicbus_attach(device_t dev)
91 {
92 #if SCAN_IICBUS
93 unsigned char addr;
94 #endif
95 struct iicbus_softc *sc = IICBUS_SOFTC(dev);
96 int strict;
97
98 sc->dev = dev;
99 mtx_init(&sc->lock, "iicbus", NULL, MTX_DEF);
100 iicbus_init_frequency(dev, 0);
101 iicbus_reset(dev, IIC_FASTEST, 0, NULL);
102 if (resource_int_value(device_get_name(dev),
103 device_get_unit(dev), "strict", &strict) == 0)
104 sc->strict = strict;
105 else
106 sc->strict = 1;
107
108 /* device probing is meaningless since the bus is supposed to be
109 * hot-plug. Moreover, some I2C chips do not appreciate random
110 * accesses like stop after start to fast, reads for less than
111 * x bytes...
112 */
113 #if SCAN_IICBUS
114 printf("Probing for devices on iicbus%d:", device_get_unit(dev));
115
116 /* probe any devices */
117 for (addr = 16; addr < 240; addr++) {
118 if (iic_probe_device(dev, (u_char)addr)) {
119 printf(" <%x>", addr);
120 }
121 }
122 printf("\n");
123 #endif
124 bus_generic_probe(dev);
125 bus_enumerate_hinted_children(dev);
126 bus_generic_attach(dev);
127 return (0);
128 }
129
130 static int
iicbus_detach(device_t dev)131 iicbus_detach(device_t dev)
132 {
133 struct iicbus_softc *sc = IICBUS_SOFTC(dev);
134
135 iicbus_reset(dev, IIC_FASTEST, 0, NULL);
136 bus_generic_detach(dev);
137 mtx_destroy(&sc->lock);
138 return (0);
139 }
140
141 static int
iicbus_print_child(device_t dev,device_t child)142 iicbus_print_child(device_t dev, device_t child)
143 {
144 struct iicbus_ivar *devi = IICBUS_IVAR(child);
145 int retval = 0;
146
147 retval += bus_print_child_header(dev, child);
148 if (devi->addr != 0)
149 retval += printf(" at addr %#x", devi->addr);
150 retval += bus_print_child_footer(dev, child);
151
152 return (retval);
153 }
154
155 static void
iicbus_probe_nomatch(device_t bus,device_t child)156 iicbus_probe_nomatch(device_t bus, device_t child)
157 {
158 struct iicbus_ivar *devi = IICBUS_IVAR(child);
159
160 device_printf(bus, "<unknown card>");
161 printf(" at addr %#x\n", devi->addr);
162 return;
163 }
164
165 static int
iicbus_child_location_str(device_t bus,device_t child,char * buf,size_t buflen)166 iicbus_child_location_str(device_t bus, device_t child, char *buf,
167 size_t buflen)
168 {
169 struct iicbus_ivar *devi = IICBUS_IVAR(child);
170
171 snprintf(buf, buflen, "addr=%#x", devi->addr);
172 return (0);
173 }
174
175 static int
iicbus_child_pnpinfo_str(device_t bus,device_t child,char * buf,size_t buflen)176 iicbus_child_pnpinfo_str(device_t bus, device_t child, char *buf,
177 size_t buflen)
178 {
179 *buf = '\0';
180 return (0);
181 }
182
183 static int
iicbus_read_ivar(device_t bus,device_t child,int which,uintptr_t * result)184 iicbus_read_ivar(device_t bus, device_t child, int which, uintptr_t *result)
185 {
186 struct iicbus_ivar *devi = IICBUS_IVAR(child);
187
188 switch (which) {
189 default:
190 return (EINVAL);
191 case IICBUS_IVAR_ADDR:
192 *result = devi->addr;
193 break;
194 }
195 return (0);
196 }
197
198 static device_t
iicbus_add_child(device_t dev,u_int order,const char * name,int unit)199 iicbus_add_child(device_t dev, u_int order, const char *name, int unit)
200 {
201 device_t child;
202 struct iicbus_ivar *devi;
203
204 child = device_add_child_ordered(dev, order, name, unit);
205 if (child == NULL)
206 return (child);
207 devi = malloc(sizeof(struct iicbus_ivar), M_DEVBUF, M_NOWAIT | M_ZERO);
208 if (devi == NULL) {
209 device_delete_child(dev, child);
210 return (0);
211 }
212 device_set_ivars(child, devi);
213 return (child);
214 }
215
216 static void
iicbus_hinted_child(device_t bus,const char * dname,int dunit)217 iicbus_hinted_child(device_t bus, const char *dname, int dunit)
218 {
219 device_t child;
220 struct iicbus_ivar *devi;
221
222 child = BUS_ADD_CHILD(bus, 0, dname, dunit);
223 devi = IICBUS_IVAR(child);
224 resource_int_value(dname, dunit, "addr", &devi->addr);
225 }
226
227 int
iicbus_generic_intr(device_t dev,int event,char * buf)228 iicbus_generic_intr(device_t dev, int event, char *buf)
229 {
230
231 return (0);
232 }
233
234 int
iicbus_null_callback(device_t dev,int index,caddr_t data)235 iicbus_null_callback(device_t dev, int index, caddr_t data)
236 {
237
238 return (0);
239 }
240
241 int
iicbus_null_repeated_start(device_t dev,u_char addr)242 iicbus_null_repeated_start(device_t dev, u_char addr)
243 {
244
245 return (IIC_ENOTSUPP);
246 }
247
248 void
iicbus_init_frequency(device_t dev,u_int bus_freq)249 iicbus_init_frequency(device_t dev, u_int bus_freq)
250 {
251 struct iicbus_softc *sc = IICBUS_SOFTC(dev);
252
253 /*
254 * If a bus frequency value was passed in, use it. Otherwise initialize
255 * it first to the standard i2c 100KHz frequency, then override that
256 * from a hint if one exists.
257 */
258 if (bus_freq > 0)
259 sc->bus_freq = bus_freq;
260 else {
261 sc->bus_freq = 100000;
262 resource_int_value(device_get_name(dev), device_get_unit(dev),
263 "frequency", (int *)&sc->bus_freq);
264 }
265 /*
266 * Set up the sysctl that allows the bus frequency to be changed.
267 * It is flagged as a tunable so that the user can set the value in
268 * loader(8), and that will override any other setting from any source.
269 * The sysctl tunable/value is the one most directly controlled by the
270 * user and thus the one that always takes precedence.
271 */
272 SYSCTL_ADD_UINT(device_get_sysctl_ctx(dev),
273 SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
274 OID_AUTO, "frequency", CTLFLAG_RW | CTLFLAG_TUN, &sc->bus_freq,
275 sc->bus_freq, "Bus frequency in Hz");
276 }
277
278 static u_int
iicbus_get_frequency(device_t dev,u_char speed)279 iicbus_get_frequency(device_t dev, u_char speed)
280 {
281 struct iicbus_softc *sc = IICBUS_SOFTC(dev);
282
283 /*
284 * If the frequency has not been configured for the bus, or the request
285 * is specifically for SLOW speed, use the standard 100KHz rate, else
286 * use the configured bus speed.
287 */
288 if (sc->bus_freq == 0 || speed == IIC_SLOW)
289 return (100000);
290 return (sc->bus_freq);
291 }
292
293 static device_method_t iicbus_methods[] = {
294 /* device interface */
295 DEVMETHOD(device_probe, iicbus_probe),
296 DEVMETHOD(device_attach, iicbus_attach),
297 DEVMETHOD(device_detach, iicbus_detach),
298
299 /* bus interface */
300 DEVMETHOD(bus_add_child, iicbus_add_child),
301 DEVMETHOD(bus_print_child, iicbus_print_child),
302 DEVMETHOD(bus_probe_nomatch, iicbus_probe_nomatch),
303 DEVMETHOD(bus_read_ivar, iicbus_read_ivar),
304 DEVMETHOD(bus_child_pnpinfo_str, iicbus_child_pnpinfo_str),
305 DEVMETHOD(bus_child_location_str, iicbus_child_location_str),
306 DEVMETHOD(bus_hinted_child, iicbus_hinted_child),
307
308 /* iicbus interface */
309 DEVMETHOD(iicbus_transfer, iicbus_transfer),
310 DEVMETHOD(iicbus_get_frequency, iicbus_get_frequency),
311
312 DEVMETHOD_END
313 };
314
315 driver_t iicbus_driver = {
316 "iicbus",
317 iicbus_methods,
318 sizeof(struct iicbus_softc),
319 };
320
321 devclass_t iicbus_devclass;
322
323 MODULE_VERSION(iicbus, IICBUS_MODVER);
324 DRIVER_MODULE(iicbus, iichb, iicbus_driver, iicbus_devclass, 0, 0);
325
326