1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2020 Alstom Group.
5 * Copyright (c) 2020 Semihalf.
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 ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD$");
30
31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/bus.h>
34#include <sys/clock.h>
35#include <sys/kernel.h>
36#include <sys/lock.h>
37#include <sys/module.h>
38
39#include <dev/ofw/ofw_bus.h>
40#include <dev/ofw/ofw_bus_subr.h>
41
42#include <dev/iicbus/iiconf.h>
43#include <dev/iicbus/iicbus.h>
44
45#include "clock_if.h"
46#include "iicbus_if.h"
47
48#define	BIT(x)			(1 << (x))
49
50#define RX8803_TIME		0x0
51#define RX8803_FLAGS		0xE
52#define RX8803_CTRL		0xF
53
54#define RX8803_FLAGS_V1F	BIT(0)
55#define RX8803_FLAGS_V2F	BIT(1)
56
57#define RX8803_CTRL_DISABLE	BIT(0)
58
59#define HALF_OF_SEC_NS		500000000
60#define MAX_WRITE_LEN		16
61
62struct rx8803_time {
63	uint8_t sec;
64	uint8_t min;
65	uint8_t hour;
66	uint8_t dow;
67	uint8_t day;
68	uint8_t mon;
69	uint8_t year;
70};
71
72static int rx8803_probe(device_t dev);
73static int rx8803_attach(device_t dev);
74static int rx8803_detach(device_t dev);
75
76static int rx8803_gettime(device_t dev, struct timespec *ts);
77static int rx8803_settime(device_t dev, struct timespec *ts);
78
79static int rx8803_check_status(device_t dev);
80
81static int
82rx8803_check_status(device_t dev)
83{
84	uint8_t flags;
85	int rc;
86
87	rc = iicdev_readfrom(dev, RX8803_FLAGS, &flags, 1, IIC_WAIT);
88	if (rc != 0)
89		return (rc);
90
91	if (flags & RX8803_FLAGS_V2F) {
92		device_printf(dev, "Low voltage flag set, date is incorrect\n");
93		return (ENXIO);
94	}
95
96	return (0);
97}
98
99static int
100rx8803_gettime(device_t dev, struct timespec *ts)
101{
102	struct rx8803_time data;
103	struct bcd_clocktime bcd;
104	int rc;
105
106	rc = rx8803_check_status(dev);
107	if (rc != 0)
108		return (rc);
109
110	rc = iicdev_readfrom(dev,
111	    RX8803_TIME,
112	    &data, sizeof(struct rx8803_time),
113	    IIC_WAIT);
114	if (rc != 0)
115		return (rc);
116
117	bcd.nsec = 0;
118	bcd.sec = data.sec & 0x7F;
119	bcd.min = data.min & 0x7F;
120	bcd.hour = data.hour & 0x3F;
121	bcd.dow = flsl(data.dow & 0x7F) - 1;
122	bcd.day = data.day & 0x3F;
123	bcd.mon = (data.mon & 0x1F);
124	bcd.year = data.year;
125
126	clock_dbgprint_bcd(dev, CLOCK_DBG_READ, &bcd);
127
128	rc = clock_bcd_to_ts(&bcd, ts, false);
129	return (rc);
130}
131
132static int
133rx8803_settime(device_t dev, struct timespec *ts)
134{
135	struct rx8803_time data;
136	struct bcd_clocktime bcd;
137	device_t bus;
138	uint8_t reg;
139	int rc;
140
141	bus = device_get_parent(dev);
142
143	ts->tv_sec -= utc_offset();
144	clock_ts_to_bcd(ts, &bcd, false);
145	clock_dbgprint_bcd(dev, CLOCK_DBG_WRITE, &bcd);
146
147	data.sec = bcd.sec;
148	data.min = bcd.min;
149	data.hour = bcd.hour;
150	data.dow = 1 << bcd.dow;
151	data.day = bcd.day;
152	data.mon = bcd.mon;
153	data.year = bcd.year;
154
155	if (ts->tv_nsec > HALF_OF_SEC_NS)
156		data.sec++;
157
158	/* First disable clock. */
159	rc = iicdev_readfrom(dev, RX8803_CTRL, &reg, sizeof(uint8_t), IIC_WAIT);
160	if (rc != 0)
161		return (rc);
162
163	reg |= RX8803_CTRL_DISABLE;
164
165	rc = iicdev_writeto(dev, RX8803_CTRL, &reg, sizeof(uint8_t), IIC_WAIT);
166	if (rc != 0)
167		return (rc);
168
169	/* Update the date. */
170	rc = iicdev_writeto(dev,
171	    RX8803_TIME,
172	    &data, sizeof(struct rx8803_time),
173	    IIC_WAIT);
174	if (rc != 0)
175		return (rc);
176
177	/* Now restart it. */
178	reg &= ~RX8803_CTRL_DISABLE;
179	rc = iicdev_writeto(dev, RX8803_CTRL, &reg, sizeof(uint8_t), IIC_WAIT);
180	if (rc != 0)
181		return (rc);
182
183	/* Clear low voltage flags, as we have just updated the clock. */
184	rc = iicdev_readfrom(dev, RX8803_FLAGS, &reg, sizeof(uint8_t), IIC_WAIT);
185	if (rc != 0)
186		return (rc);
187
188	reg &= ~(RX8803_FLAGS_V1F | RX8803_FLAGS_V2F);
189	rc = iicdev_writeto(dev, RX8803_FLAGS, &reg, sizeof(uint8_t), IIC_WAIT);
190	return (rc);
191}
192
193static int
194rx8803_probe(device_t dev)
195{
196
197	if (!ofw_bus_is_compatible(dev, "epson,rx8803"))
198		return (ENXIO);
199
200	device_set_desc(dev, "Epson RX8803 Real Time Clock");
201
202	return (BUS_PROBE_GENERIC);
203}
204
205static int
206rx8803_attach(device_t dev)
207{
208
209	/* Set 1 sec resolution. */
210	clock_register_flags(dev, 1000000, 0);
211	clock_schedule(dev, 1);
212
213	return (0);
214
215}
216
217static int
218rx8803_detach(device_t dev)
219{
220
221	clock_unregister(dev);
222
223	return (0);
224}
225
226static device_method_t rx8803_methods[] = {
227	DEVMETHOD(device_probe, rx8803_probe),
228	DEVMETHOD(device_attach, rx8803_attach),
229	DEVMETHOD(device_detach, rx8803_detach),
230
231	DEVMETHOD(clock_gettime, rx8803_gettime),
232	DEVMETHOD(clock_settime, rx8803_settime),
233
234	DEVMETHOD_END,
235};
236
237static driver_t rx8803_driver = {
238	"rx8803",
239	rx8803_methods,
240	0,			/* We don't need softc for this one. */
241};
242
243static devclass_t rx8803_devclass;
244
245DRIVER_MODULE(rx8803, iicbus, rx8803_driver, rx8803_devclass, NULL, NULL);
246MODULE_DEPEND(rx8803, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
247