xref: /freebsd/sys/dev/iicbus/iicbus.c (revision 4436b51dff5736e74da464946049ea6899a88938)
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/rman.h>
42 #include <sys/sysctl.h>
43 #include <sys/bus.h>
44 
45 #include <dev/iicbus/iiconf.h>
46 #include <dev/iicbus/iicbus.h>
47 
48 #include "iicbus_if.h"
49 
50 /* See comments below for why auto-scanning is a bad idea. */
51 #define SCAN_IICBUS 0
52 
53 static int
54 iicbus_probe(device_t dev)
55 {
56 
57 	device_set_desc(dev, "Philips I2C bus");
58 
59 	/* Allow other subclasses to override this driver. */
60 	return (BUS_PROBE_GENERIC);
61 }
62 
63 #if SCAN_IICBUS
64 static int
65 iic_probe_device(device_t dev, u_char addr)
66 {
67 	int count;
68 	char byte;
69 
70 	if ((addr & 1) == 0) {
71 		/* is device writable? */
72 		if (!iicbus_start(dev, (u_char)addr, 0)) {
73 			iicbus_stop(dev);
74 			return (1);
75 		}
76 	} else {
77 		/* is device readable? */
78 		if (!iicbus_block_read(dev, (u_char)addr, &byte, 1, &count))
79 			return (1);
80 	}
81 
82 	return (0);
83 }
84 #endif
85 
86 /*
87  * We add all the devices which we know about.
88  * The generic attach routine will attach them if they are alive.
89  */
90 static int
91 iicbus_attach(device_t dev)
92 {
93 #if SCAN_IICBUS
94 	unsigned char addr;
95 #endif
96 	struct iicbus_softc *sc = IICBUS_SOFTC(dev);
97 	int strict;
98 
99 	sc->dev = dev;
100 	mtx_init(&sc->lock, "iicbus", NULL, MTX_DEF);
101 	iicbus_init_frequency(dev, 0);
102 	iicbus_reset(dev, IIC_FASTEST, 0, NULL);
103 	if (resource_int_value(device_get_name(dev),
104 		device_get_unit(dev), "strict", &strict) == 0)
105 		sc->strict = strict;
106 	else
107 		sc->strict = 1;
108 
109 	/* device probing is meaningless since the bus is supposed to be
110 	 * hot-plug. Moreover, some I2C chips do not appreciate random
111 	 * accesses like stop after start to fast, reads for less than
112 	 * x bytes...
113 	 */
114 #if SCAN_IICBUS
115 	printf("Probing for devices on iicbus%d:", device_get_unit(dev));
116 
117 	/* probe any devices */
118 	for (addr = 16; addr < 240; addr++) {
119 		if (iic_probe_device(dev, (u_char)addr)) {
120 			printf(" <%x>", addr);
121 		}
122 	}
123 	printf("\n");
124 #endif
125 	bus_generic_probe(dev);
126 	bus_enumerate_hinted_children(dev);
127 	bus_generic_attach(dev);
128         return (0);
129 }
130 
131 static int
132 iicbus_detach(device_t dev)
133 {
134 	struct iicbus_softc *sc = IICBUS_SOFTC(dev);
135 
136 	iicbus_reset(dev, IIC_FASTEST, 0, NULL);
137 	bus_generic_detach(dev);
138 	mtx_destroy(&sc->lock);
139 	return (0);
140 }
141 
142 static int
143 iicbus_print_child(device_t dev, device_t child)
144 {
145 	struct iicbus_ivar *devi = IICBUS_IVAR(child);
146 	int retval = 0;
147 
148 	retval += bus_print_child_header(dev, child);
149 	if (devi->addr != 0)
150 		retval += printf(" at addr %#x", devi->addr);
151 	resource_list_print_type(&devi->rl, "irq", SYS_RES_IRQ, "%ld");
152 	retval += bus_print_child_footer(dev, child);
153 
154 	return (retval);
155 }
156 
157 static void
158 iicbus_probe_nomatch(device_t bus, device_t child)
159 {
160 	struct iicbus_ivar *devi = IICBUS_IVAR(child);
161 
162 	device_printf(bus, "<unknown card> at addr %#x\n", devi->addr);
163 }
164 
165 static int
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
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
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
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 	resource_list_init(&devi->rl);
213 	device_set_ivars(child, devi);
214 	return (child);
215 }
216 
217 static void
218 iicbus_hinted_child(device_t bus, const char *dname, int dunit)
219 {
220 	device_t child;
221 	int irq;
222 	struct iicbus_ivar *devi;
223 
224 	child = BUS_ADD_CHILD(bus, 0, dname, dunit);
225 	devi = IICBUS_IVAR(child);
226 	resource_int_value(dname, dunit, "addr", &devi->addr);
227 	if (resource_int_value(dname, dunit, "irq", &irq) == 0) {
228 		if (bus_set_resource(child, SYS_RES_IRQ, 0, irq, 1) != 0)
229 			device_printf(bus,
230 			    "warning: bus_set_resource() failed\n");
231 	}
232 }
233 
234 static struct resource_list *
235 iicbus_get_resource_list(device_t bus __unused, device_t child)
236 {
237 	struct iicbus_ivar *devi;
238 
239 	devi = IICBUS_IVAR(child);
240 	return (&devi->rl);
241 }
242 
243 int
244 iicbus_generic_intr(device_t dev, int event, char *buf)
245 {
246 
247 	return (0);
248 }
249 
250 int
251 iicbus_null_callback(device_t dev, int index, caddr_t data)
252 {
253 
254 	return (0);
255 }
256 
257 int
258 iicbus_null_repeated_start(device_t dev, u_char addr)
259 {
260 
261 	return (IIC_ENOTSUPP);
262 }
263 
264 void
265 iicbus_init_frequency(device_t dev, u_int bus_freq)
266 {
267 	struct iicbus_softc *sc = IICBUS_SOFTC(dev);
268 
269 	/*
270 	 * If a bus frequency value was passed in, use it.  Otherwise initialize
271 	 * it first to the standard i2c 100KHz frequency, then override that
272 	 * from a hint if one exists.
273 	 */
274 	if (bus_freq > 0)
275 		sc->bus_freq = bus_freq;
276 	else {
277 		sc->bus_freq = 100000;
278 		resource_int_value(device_get_name(dev), device_get_unit(dev),
279 		    "frequency", (int *)&sc->bus_freq);
280 	}
281 	/*
282 	 * Set up the sysctl that allows the bus frequency to be changed.
283 	 * It is flagged as a tunable so that the user can set the value in
284 	 * loader(8), and that will override any other setting from any source.
285 	 * The sysctl tunable/value is the one most directly controlled by the
286 	 * user and thus the one that always takes precedence.
287 	 */
288 	SYSCTL_ADD_UINT(device_get_sysctl_ctx(dev),
289 	    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
290 	    OID_AUTO, "frequency", CTLFLAG_RW | CTLFLAG_TUN, &sc->bus_freq,
291 	    sc->bus_freq, "Bus frequency in Hz");
292 }
293 
294 static u_int
295 iicbus_get_frequency(device_t dev, u_char speed)
296 {
297 	struct iicbus_softc *sc = IICBUS_SOFTC(dev);
298 
299 	/*
300 	 * If the frequency has not been configured for the bus, or the request
301 	 * is specifically for SLOW speed, use the standard 100KHz rate, else
302 	 * use the configured bus speed.
303 	 */
304 	if (sc->bus_freq == 0 || speed == IIC_SLOW)
305 		return (100000);
306 	return (sc->bus_freq);
307 }
308 
309 static device_method_t iicbus_methods[] = {
310 	/* device interface */
311 	DEVMETHOD(device_probe,		iicbus_probe),
312 	DEVMETHOD(device_attach,	iicbus_attach),
313 	DEVMETHOD(device_detach,	iicbus_detach),
314 
315 	/* bus interface */
316 	DEVMETHOD(bus_setup_intr,	bus_generic_setup_intr),
317 	DEVMETHOD(bus_teardown_intr,	bus_generic_teardown_intr),
318 	DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
319 	DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
320 	DEVMETHOD(bus_adjust_resource,	bus_generic_adjust_resource),
321 	DEVMETHOD(bus_alloc_resource,	bus_generic_rl_alloc_resource),
322 	DEVMETHOD(bus_get_resource,	bus_generic_rl_get_resource),
323 	DEVMETHOD(bus_release_resource, bus_generic_rl_release_resource),
324 	DEVMETHOD(bus_set_resource,	bus_generic_rl_set_resource),
325 	DEVMETHOD(bus_get_resource_list, iicbus_get_resource_list),
326 	DEVMETHOD(bus_add_child,	iicbus_add_child),
327 	DEVMETHOD(bus_print_child,	iicbus_print_child),
328 	DEVMETHOD(bus_probe_nomatch,	iicbus_probe_nomatch),
329 	DEVMETHOD(bus_read_ivar,	iicbus_read_ivar),
330 	DEVMETHOD(bus_child_pnpinfo_str, iicbus_child_pnpinfo_str),
331 	DEVMETHOD(bus_child_location_str, iicbus_child_location_str),
332 	DEVMETHOD(bus_hinted_child,	iicbus_hinted_child),
333 
334 	/* iicbus interface */
335 	DEVMETHOD(iicbus_transfer,	iicbus_transfer),
336 	DEVMETHOD(iicbus_get_frequency,	iicbus_get_frequency),
337 
338 	DEVMETHOD_END
339 };
340 
341 driver_t iicbus_driver = {
342         "iicbus",
343         iicbus_methods,
344         sizeof(struct iicbus_softc),
345 };
346 
347 devclass_t iicbus_devclass;
348 
349 MODULE_VERSION(iicbus, IICBUS_MODVER);
350 DRIVER_MODULE(iicbus, iichb, iicbus_driver, iicbus_devclass, 0, 0);
351