lpc_rtc.c revision 266152 
1/*-
2 * Copyright (c) 2011 Jakub Wojciech Klama <jceel@FreeBSD.org>
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/10/sys/arm/lpc/lpc_rtc.c 266152 2014-05-15 16:11:06Z ian $");
29
30#include <sys/param.h>
31#include <sys/bus.h>
32#include <sys/time.h>
33#include <sys/clock.h>
34#include <sys/resource.h>
35#include <sys/systm.h>
36#include <sys/rman.h>
37#include <sys/kernel.h>
38#include <sys/module.h>
39
40#include <machine/bus.h>
41#include <machine/resource.h>
42
43#include <dev/ofw/ofw_bus.h>
44#include <dev/ofw/ofw_bus_subr.h>
45
46#include <arm/lpc/lpcreg.h>
47
48#include "clock_if.h"
49
50struct lpc_rtc_softc {
51	device_t			lr_dev;
52	struct resource	*		lr_mem_res;
53	bus_space_tag_t			lr_bst;
54	bus_space_handle_t		lr_bsh;
55};
56
57static int lpc_rtc_probe(device_t dev);
58static int lpc_rtc_attach(device_t dev);
59static int lpc_rtc_gettime(device_t dev, struct timespec *ts);
60static int lpc_rtc_settime(device_t, struct timespec *);
61
62static int
63lpc_rtc_probe(device_t dev)
64{
65
66	if (!ofw_bus_status_okay(dev))
67		return (ENXIO);
68
69	if (!ofw_bus_is_compatible(dev, "lpc,rtc"))
70		return (ENXIO);
71
72	device_set_desc(dev, "LPC32x0 real time clock");
73	return (BUS_PROBE_DEFAULT);
74}
75
76static int
77lpc_rtc_attach(device_t dev)
78{
79	struct lpc_rtc_softc *sc = device_get_softc(dev);
80	int rid = 0;
81
82	sc->lr_dev = dev;
83
84	clock_register(dev, 1000000);
85
86	sc->lr_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
87	    RF_ACTIVE);
88	if (!sc->lr_mem_res) {
89		device_printf(dev, "cannot allocate memory window\n");
90		return (ENXIO);
91	}
92
93	sc->lr_bst = rman_get_bustag(sc->lr_mem_res);
94	sc->lr_bsh = rman_get_bushandle(sc->lr_mem_res);
95
96	return (0);
97}
98
99static int
100lpc_rtc_gettime(device_t dev, struct timespec *ts)
101{
102	struct lpc_rtc_softc *sc = device_get_softc(dev);
103
104	ts->tv_sec = bus_space_read_4(sc->lr_bst, sc->lr_bsh, LPC_RTC_UCOUNT);
105	ts->tv_nsec = 0;
106
107	return (0);
108}
109
110static int
111lpc_rtc_settime(device_t dev, struct timespec *ts)
112{
113	struct lpc_rtc_softc *sc = device_get_softc(dev);
114	uint32_t ctrl;
115
116	/* Stop RTC */
117	ctrl = bus_space_read_4(sc->lr_bst, sc->lr_bsh, LPC_RTC_CTRL);
118	bus_space_write_4(sc->lr_bst, sc->lr_bsh, LPC_RTC_CTRL, ctrl | LPC_RTC_CTRL_DISABLE);
119
120	/* Write actual value */
121	bus_space_write_4(sc->lr_bst, sc->lr_bsh, LPC_RTC_UCOUNT, ts->tv_sec);
122
123	/* Start RTC */
124	ctrl = bus_space_read_4(sc->lr_bst, sc->lr_bsh, LPC_RTC_CTRL);
125	bus_space_write_4(sc->lr_bst, sc->lr_bsh, LPC_RTC_CTRL, ctrl & ~LPC_RTC_CTRL_DISABLE);
126
127	return (0);
128}
129
130static device_method_t lpc_rtc_methods[] = {
131	/* Device interface */
132	DEVMETHOD(device_probe,		lpc_rtc_probe),
133	DEVMETHOD(device_attach,	lpc_rtc_attach),
134
135	/* Clock interface */
136	DEVMETHOD(clock_gettime,	lpc_rtc_gettime),
137	DEVMETHOD(clock_settime,	lpc_rtc_settime),
138
139	{ 0, 0 },
140};
141
142static driver_t lpc_rtc_driver = {
143	"rtc",
144	lpc_rtc_methods,
145	sizeof(struct lpc_rtc_softc),
146};
147
148static devclass_t lpc_rtc_devclass;
149
150DRIVER_MODULE(rtc, simplebus, lpc_rtc_driver, lpc_rtc_devclass, 0, 0);
151