1 /* $NetBSD: s390.c,v 1.7 2021/01/30 17:38:57 thorpej Exp $ */
2
3 /*-
4 * Copyright (c) 2011 Frank Wille.
5 * All rights reserved.
6 *
7 * Written by Frank Wille for The NetBSD Project.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
22 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #include <sys/cdefs.h>
32 __KERNEL_RCSID(0, "$NetBSD: s390.c,v 1.7 2021/01/30 17:38:57 thorpej Exp $");
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/device.h>
37 #include <sys/conf.h>
38
39 #include <dev/clock_subr.h>
40
41 #include <dev/i2c/i2cvar.h>
42 #include <dev/i2c/s390reg.h>
43
44 struct s390rtc_softc {
45 device_t sc_dev;
46 i2c_tag_t sc_tag;
47 i2c_addr_t sc_addr;
48 struct todr_chip_handle sc_todr;
49 };
50
51 static int s390rtc_match(device_t, cfdata_t, void *);
52 static void s390rtc_attach(device_t, device_t, void *);
53
54 CFATTACH_DECL_NEW(s390rtc, sizeof(struct s390rtc_softc),
55 s390rtc_match, s390rtc_attach, NULL, NULL);
56
57 static int s390rtc_gettime_ymdhms(struct todr_chip_handle *,
58 struct clock_ymdhms *);
59 static int s390rtc_settime_ymdhms(struct todr_chip_handle *,
60 struct clock_ymdhms *);
61 static int s390rtc_read(struct s390rtc_softc *, int, uint8_t *, size_t);
62 static int s390rtc_write(struct s390rtc_softc *, int, uint8_t *, size_t);
63 static uint8_t bitreverse(uint8_t);
64
65 static const struct device_compatible_entry compat_data[] = {
66 { .compat = "sii,s35390a" },
67 DEVICE_COMPAT_EOL
68 };
69
70 static int
s390rtc_match(device_t parent,cfdata_t cf,void * arg)71 s390rtc_match(device_t parent, cfdata_t cf, void *arg)
72 {
73 struct i2c_attach_args *ia = arg;
74 int match_result;
75
76 if (iic_use_direct_match(ia, cf, compat_data, &match_result))
77 return match_result;
78
79 /* indirect config - check typical address */
80 if (ia->ia_addr == S390_ADDR)
81 return I2C_MATCH_ADDRESS_ONLY;
82
83 return 0;
84 }
85
86 static void
s390rtc_attach(device_t parent,device_t self,void * arg)87 s390rtc_attach(device_t parent, device_t self, void *arg)
88 {
89 struct s390rtc_softc *sc = device_private(self);
90 struct i2c_attach_args *ia = arg;
91 uint8_t reg[1];
92
93 aprint_naive(": Real-time Clock\n");
94 aprint_normal(": Seiko Instruments 35390A Real-time Clock\n");
95
96 sc->sc_tag = ia->ia_tag;
97 sc->sc_addr = ia->ia_addr;
98 sc->sc_dev = self;
99
100 /* Reset the chip and turn on 24h mode, after power-off or battery. */
101 if (s390rtc_read(sc, S390_STATUS1, reg, sizeof(reg)))
102 return;
103 if (reg[0] & (S390_ST1_POC | S390_ST1_BLD)) {
104 reg[0] |= S390_ST1_24H | S390_ST1_RESET;
105 if (s390rtc_write(sc, S390_STATUS1, reg, sizeof(reg)))
106 return;
107 }
108
109 /* Disable the test mode, when enabled. */
110 if (s390rtc_read(sc, S390_STATUS2, reg, sizeof(reg)))
111 return;
112 if ((reg[0] & S390_ST2_TEST)) {
113 reg[0] &= ~S390_ST2_TEST;
114 if (s390rtc_write(sc, S390_STATUS2, reg, sizeof(reg)))
115 return;
116 }
117
118 sc->sc_todr.cookie = sc;
119 sc->sc_todr.todr_gettime = NULL;
120 sc->sc_todr.todr_settime = NULL;
121 sc->sc_todr.todr_gettime_ymdhms = s390rtc_gettime_ymdhms;
122 sc->sc_todr.todr_settime_ymdhms = s390rtc_settime_ymdhms;
123 sc->sc_todr.todr_setwen = NULL;
124 todr_attach(&sc->sc_todr);
125 }
126
127 static int
s390rtc_gettime_ymdhms(struct todr_chip_handle * ch,struct clock_ymdhms * dt)128 s390rtc_gettime_ymdhms(struct todr_chip_handle *ch, struct clock_ymdhms *dt)
129 {
130 struct s390rtc_softc *sc = ch->cookie;
131 uint8_t bcd[S390_RT1_NBYTES];
132 int error;
133
134 if ((error = s390rtc_read(sc, S390_REALTIME1, bcd,
135 S390_RT1_NBYTES)) != 0)
136 return error;
137
138 /*
139 * Convert the register values into something useable.
140 */
141 dt->dt_sec = bcdtobin(bcd[S390_RT1_SECOND]);
142 dt->dt_min = bcdtobin(bcd[S390_RT1_MINUTE]);
143 dt->dt_hour = bcdtobin(bcd[S390_RT1_HOUR] & 0x3f);
144 dt->dt_day = bcdtobin(bcd[S390_RT1_DAY]);
145 dt->dt_mon = bcdtobin(bcd[S390_RT1_MONTH]);
146 dt->dt_year = bcdtobin(bcd[S390_RT1_YEAR]) + 2000;
147
148 return 0;
149 }
150
151 static int
s390rtc_settime_ymdhms(struct todr_chip_handle * ch,struct clock_ymdhms * dt)152 s390rtc_settime_ymdhms(struct todr_chip_handle *ch, struct clock_ymdhms *dt)
153 {
154 struct s390rtc_softc *sc = ch->cookie;
155 uint8_t bcd[S390_RT1_NBYTES];
156
157 /*
158 * Convert our time representation into something the S-xx390
159 * can understand.
160 */
161 bcd[S390_RT1_SECOND] = bintobcd(dt->dt_sec);
162 bcd[S390_RT1_MINUTE] = bintobcd(dt->dt_min);
163 bcd[S390_RT1_HOUR] = bintobcd(dt->dt_hour);
164 bcd[S390_RT1_DAY] = bintobcd(dt->dt_day);
165 bcd[S390_RT1_WDAY] = bintobcd(dt->dt_wday);
166 bcd[S390_RT1_MONTH] = bintobcd(dt->dt_mon);
167 bcd[S390_RT1_YEAR] = bintobcd(dt->dt_year % 100);
168
169 return s390rtc_write(sc, S390_REALTIME1, bcd, S390_RT1_NBYTES);
170 }
171
172 static int
s390rtc_read(struct s390rtc_softc * sc,int reg,uint8_t * buf,size_t len)173 s390rtc_read(struct s390rtc_softc *sc, int reg, uint8_t *buf, size_t len)
174 {
175 int i, error;
176
177 if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0) {
178 aprint_error_dev(sc->sc_dev,
179 "%s: failed to acquire I2C bus\n", __func__);
180 return error;
181 }
182
183 if ((error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
184 sc->sc_addr + reg, NULL, 0, buf, len, 0)) != 0) {
185 iic_release_bus(sc->sc_tag, 0);
186 aprint_error_dev(sc->sc_dev,
187 "%s: failed to read reg%d\n", __func__, reg);
188 return error;
189 }
190
191 iic_release_bus(sc->sc_tag, 0);
192
193 /* this chip returns each byte in reverse order */
194 for (i = 0; i < len; i++)
195 buf[i] = bitreverse(buf[i]);
196
197 return 0;
198 }
199
200 static int
s390rtc_write(struct s390rtc_softc * sc,int reg,uint8_t * buf,size_t len)201 s390rtc_write(struct s390rtc_softc *sc, int reg, uint8_t *buf, size_t len)
202 {
203 int i, error;
204
205 if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0) {
206 aprint_error_dev(sc->sc_dev,
207 "%s: failed to acquire I2C bus\n", __func__);
208 return error;
209 }
210
211 /* this chip expects each byte in reverse order */
212 for (i = 0; i < len; i++)
213 buf[i] = bitreverse(buf[i]);
214
215 if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP,
216 sc->sc_addr + reg, NULL, 0, buf, len, 0)) != 0) {
217 iic_release_bus(sc->sc_tag, 0);
218 aprint_error_dev(sc->sc_dev,
219 "%s: failed to write reg%d\n", __func__, reg);
220 return error;
221 }
222
223 iic_release_bus(sc->sc_tag, 0);
224 return 0;
225 }
226
227 static uint8_t
bitreverse(uint8_t x)228 bitreverse(uint8_t x)
229 {
230 static unsigned char nibbletab[16] = {
231 0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15
232 };
233
234 return (nibbletab[x & 15] << 4) | nibbletab[x >> 4];
235 }
236