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: stable/11/sys/dev/iicbus/iicbus.c 350031 2019-07-16 15:02:28Z avg $");
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
53static int
54iicbus_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
64static int
65iic_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 */
90static int
91iicbus_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
131static int
132iicbus_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	device_delete_children(dev);
139	mtx_destroy(&sc->lock);
140	return (0);
141}
142
143static int
144iicbus_print_child(device_t dev, device_t child)
145{
146	struct iicbus_ivar *devi = IICBUS_IVAR(child);
147	int retval = 0;
148
149	retval += bus_print_child_header(dev, child);
150	if (devi->addr != 0)
151		retval += printf(" at addr %#x", devi->addr);
152	resource_list_print_type(&devi->rl, "irq", SYS_RES_IRQ, "%jd");
153	retval += bus_print_child_footer(dev, child);
154
155	return (retval);
156}
157
158static void
159iicbus_probe_nomatch(device_t bus, device_t child)
160{
161	struct iicbus_ivar *devi = IICBUS_IVAR(child);
162
163	device_printf(bus, "<unknown card> at addr %#x\n", devi->addr);
164}
165
166static int
167iicbus_child_location_str(device_t bus, device_t child, char *buf,
168    size_t buflen)
169{
170	struct iicbus_ivar *devi = IICBUS_IVAR(child);
171
172	snprintf(buf, buflen, "addr=%#x", devi->addr);
173	return (0);
174}
175
176static int
177iicbus_child_pnpinfo_str(device_t bus, device_t child, char *buf,
178    size_t buflen)
179{
180	*buf = '\0';
181	return (0);
182}
183
184static int
185iicbus_read_ivar(device_t bus, device_t child, int which, uintptr_t *result)
186{
187	struct iicbus_ivar *devi = IICBUS_IVAR(child);
188
189	switch (which) {
190	default:
191		return (EINVAL);
192	case IICBUS_IVAR_ADDR:
193		*result = devi->addr;
194		break;
195	}
196	return (0);
197}
198
199static int
200iicbus_write_ivar(device_t bus, device_t child, int which, uintptr_t value)
201{
202	struct iicbus_ivar *devi = IICBUS_IVAR(child);
203
204	switch (which) {
205	default:
206		return (EINVAL);
207	case IICBUS_IVAR_ADDR:
208		if (devi->addr != 0)
209			return (EINVAL);
210		devi->addr = value;
211	}
212	return (0);
213}
214
215static device_t
216iicbus_add_child(device_t dev, u_int order, const char *name, int unit)
217{
218	device_t child;
219	struct iicbus_ivar *devi;
220
221	child = device_add_child_ordered(dev, order, name, unit);
222	if (child == NULL)
223		return (child);
224	devi = malloc(sizeof(struct iicbus_ivar), M_DEVBUF, M_NOWAIT | M_ZERO);
225	if (devi == NULL) {
226		device_delete_child(dev, child);
227		return (0);
228	}
229	resource_list_init(&devi->rl);
230	device_set_ivars(child, devi);
231	return (child);
232}
233
234static void
235iicbus_hinted_child(device_t bus, const char *dname, int dunit)
236{
237	device_t child;
238	int irq;
239	struct iicbus_ivar *devi;
240
241	child = BUS_ADD_CHILD(bus, 0, dname, dunit);
242	devi = IICBUS_IVAR(child);
243	resource_int_value(dname, dunit, "addr", &devi->addr);
244	if (resource_int_value(dname, dunit, "irq", &irq) == 0) {
245		if (bus_set_resource(child, SYS_RES_IRQ, 0, irq, 1) != 0)
246			device_printf(bus,
247			    "warning: bus_set_resource() failed\n");
248	}
249}
250
251static struct resource_list *
252iicbus_get_resource_list(device_t bus __unused, device_t child)
253{
254	struct iicbus_ivar *devi;
255
256	devi = IICBUS_IVAR(child);
257	return (&devi->rl);
258}
259
260int
261iicbus_generic_intr(device_t dev, int event, char *buf)
262{
263
264	return (0);
265}
266
267int
268iicbus_null_callback(device_t dev, int index, caddr_t data)
269{
270
271	return (0);
272}
273
274int
275iicbus_null_repeated_start(device_t dev, u_char addr)
276{
277
278	return (IIC_ENOTSUPP);
279}
280
281void
282iicbus_init_frequency(device_t dev, u_int bus_freq)
283{
284	struct iicbus_softc *sc = IICBUS_SOFTC(dev);
285
286	/*
287	 * If a bus frequency value was passed in, use it.  Otherwise initialize
288	 * it first to the standard i2c 100KHz frequency, then override that
289	 * from a hint if one exists.
290	 */
291	if (bus_freq > 0)
292		sc->bus_freq = bus_freq;
293	else {
294		sc->bus_freq = 100000;
295		resource_int_value(device_get_name(dev), device_get_unit(dev),
296		    "frequency", (int *)&sc->bus_freq);
297	}
298	/*
299	 * Set up the sysctl that allows the bus frequency to be changed.
300	 * It is flagged as a tunable so that the user can set the value in
301	 * loader(8), and that will override any other setting from any source.
302	 * The sysctl tunable/value is the one most directly controlled by the
303	 * user and thus the one that always takes precedence.
304	 */
305	SYSCTL_ADD_UINT(device_get_sysctl_ctx(dev),
306	    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
307	    OID_AUTO, "frequency", CTLFLAG_RW | CTLFLAG_TUN, &sc->bus_freq,
308	    sc->bus_freq, "Bus frequency in Hz");
309}
310
311static u_int
312iicbus_get_frequency(device_t dev, u_char speed)
313{
314	struct iicbus_softc *sc = IICBUS_SOFTC(dev);
315
316	/*
317	 * If the frequency has not been configured for the bus, or the request
318	 * is specifically for SLOW speed, use the standard 100KHz rate, else
319	 * use the configured bus speed.
320	 */
321	if (sc->bus_freq == 0 || speed == IIC_SLOW)
322		return (100000);
323	return (sc->bus_freq);
324}
325
326static device_method_t iicbus_methods[] = {
327	/* device interface */
328	DEVMETHOD(device_probe,		iicbus_probe),
329	DEVMETHOD(device_attach,	iicbus_attach),
330	DEVMETHOD(device_detach,	iicbus_detach),
331
332	/* bus interface */
333	DEVMETHOD(bus_setup_intr,	bus_generic_setup_intr),
334	DEVMETHOD(bus_teardown_intr,	bus_generic_teardown_intr),
335	DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
336	DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
337	DEVMETHOD(bus_adjust_resource,	bus_generic_adjust_resource),
338	DEVMETHOD(bus_alloc_resource,	bus_generic_rl_alloc_resource),
339	DEVMETHOD(bus_get_resource,	bus_generic_rl_get_resource),
340	DEVMETHOD(bus_release_resource, bus_generic_rl_release_resource),
341	DEVMETHOD(bus_set_resource,	bus_generic_rl_set_resource),
342	DEVMETHOD(bus_get_resource_list, iicbus_get_resource_list),
343	DEVMETHOD(bus_add_child,	iicbus_add_child),
344	DEVMETHOD(bus_print_child,	iicbus_print_child),
345	DEVMETHOD(bus_probe_nomatch,	iicbus_probe_nomatch),
346	DEVMETHOD(bus_read_ivar,	iicbus_read_ivar),
347	DEVMETHOD(bus_write_ivar,	iicbus_write_ivar),
348	DEVMETHOD(bus_child_pnpinfo_str, iicbus_child_pnpinfo_str),
349	DEVMETHOD(bus_child_location_str, iicbus_child_location_str),
350	DEVMETHOD(bus_hinted_child,	iicbus_hinted_child),
351
352	/* iicbus interface */
353	DEVMETHOD(iicbus_transfer,	iicbus_transfer),
354	DEVMETHOD(iicbus_get_frequency,	iicbus_get_frequency),
355
356	DEVMETHOD_END
357};
358
359driver_t iicbus_driver = {
360        "iicbus",
361        iicbus_methods,
362        sizeof(struct iicbus_softc),
363};
364
365devclass_t iicbus_devclass;
366
367MODULE_VERSION(iicbus, IICBUS_MODVER);
368DRIVER_MODULE(iicbus, iichb, iicbus_driver, iicbus_devclass, 0, 0);
369