1 /* $Id: imx23_rtc.c,v 1.2 2019/10/18 04:09:01 msaitoh Exp $ */
2
3 /*
4 * Copyright (c) 2014 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Petri Laakso.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/param.h>
33 #include <sys/types.h>
34 #include <sys/bus.h>
35 #include <sys/cdefs.h>
36 #include <sys/device.h>
37 #include <sys/errno.h>
38
39 #include <arm/imx/imx23_rtcreg.h>
40 #include <arm/imx/imx23_rtcvar.h>
41 #include <arm/imx/imx23var.h>
42
43 typedef struct rtc_softc {
44 device_t sc_dev;
45 bus_space_tag_t sc_iot;
46 bus_space_handle_t sc_hdl;
47 } *rtc_softc_t;
48
49 static int rtc_match(device_t, cfdata_t, void *);
50 static void rtc_attach(device_t, device_t, void *);
51 static int rtc_activate(device_t, enum devact);
52
53 static void rtc_init(struct rtc_softc *);
54 static void rtc_reset(struct rtc_softc *);
55
56 static rtc_softc_t _sc = NULL;
57
58 CFATTACH_DECL3_NEW(rtc,
59 sizeof(struct rtc_softc),
60 rtc_match,
61 rtc_attach,
62 NULL,
63 rtc_activate,
64 NULL,
65 NULL,
66 0
67 );
68
69 #define RTC_RD(sc, reg) \
70 bus_space_read_4(sc->sc_iot, sc->sc_hdl, (reg))
71 #define RTC_WR(sc, reg, val) \
72 bus_space_write_4(sc->sc_iot, sc->sc_hdl, (reg), (val))
73
74 #define RTC_SOFT_RST_LOOP 455 /* At least 1 us ... */
75
76 static int
rtc_match(device_t parent,cfdata_t match,void * aux)77 rtc_match(device_t parent, cfdata_t match, void *aux)
78 {
79 struct apb_attach_args *aa = aux;
80
81 if ((aa->aa_addr == HW_RTC_BASE) &&
82 (aa->aa_size == HW_RTC_BASE_SIZE))
83 return 1;
84
85 return 0;
86 }
87
88 static void
rtc_attach(device_t parent,device_t self,void * aux)89 rtc_attach(device_t parent, device_t self, void *aux)
90 {
91 struct rtc_softc *sc = device_private(self);
92 struct apb_attach_args *aa = aux;
93 static int rtc_attached = 0;
94
95 sc->sc_dev = self;
96 sc->sc_iot = aa->aa_iot;
97
98 if (rtc_attached) {
99 aprint_error_dev(sc->sc_dev, "rtc is already attached\n");
100 return;
101 }
102
103 if (bus_space_map(sc->sc_iot, aa->aa_addr, aa->aa_size, 0,
104 &sc->sc_hdl))
105 {
106 aprint_error_dev(sc->sc_dev, "Unable to map bus space\n");
107 return;
108 }
109
110
111 rtc_init(sc);
112 rtc_reset(sc);
113
114 aprint_normal("\n");
115
116 rtc_attached = 1;
117
118 return;
119 }
120
121 static int
rtc_activate(device_t self,enum devact act)122 rtc_activate(device_t self, enum devact act)
123 {
124
125 return EOPNOTSUPP;
126 }
127
128 static void
rtc_init(struct rtc_softc * sc)129 rtc_init(struct rtc_softc *sc)
130 {
131 _sc = sc;
132 return;
133 }
134
135 /*
136 * Remove pulldown resistors on the headphone outputs.
137 */
138 void
rtc_release_gnd(int val)139 rtc_release_gnd(int val)
140 {
141 struct rtc_softc *sc = _sc;
142
143 if (sc == NULL) {
144 aprint_error("rtc is not initialized");
145 return;
146 }
147 if(val)
148 RTC_WR(sc, HW_RTC_PERSISTENT0_SET, (1<<19));
149 else
150 RTC_WR(sc, HW_RTC_PERSISTENT0_CLR, (1<<19));
151
152 return;
153 }
154
155 /*
156 * Reset the RTC block.
157 *
158 * Inspired by i.MX23 RM "39.3.10 Correct Way to Soft Reset a Block"
159 */
160 static void
rtc_reset(struct rtc_softc * sc)161 rtc_reset(struct rtc_softc *sc)
162 {
163 unsigned int loop;
164
165 /* Prepare for soft-reset by making sure that SFTRST is not currently
166 * asserted. Also clear CLKGATE so we can wait for its assertion below.
167 */
168 RTC_WR(sc, HW_RTC_CTRL_CLR, HW_RTC_CTRL_SFTRST);
169
170 /* Wait at least a microsecond for SFTRST to deassert. */
171 loop = 0;
172 while ((RTC_RD(sc, HW_RTC_CTRL) & HW_RTC_CTRL_SFTRST) ||
173 (loop < RTC_SOFT_RST_LOOP))
174 loop++;
175
176 /* Clear CLKGATE so we can wait for its assertion below. */
177 RTC_WR(sc, HW_RTC_CTRL_CLR, HW_RTC_CTRL_CLKGATE);
178
179 /* Soft-reset the block. */
180 RTC_WR(sc, HW_RTC_CTRL_SET, HW_RTC_CTRL_SFTRST);
181
182 /* Wait until clock is in the gated state. */
183 while (!(RTC_RD(sc, HW_RTC_CTRL) & HW_RTC_CTRL_CLKGATE));
184
185 /* Bring block out of reset. */
186 RTC_WR(sc, HW_RTC_CTRL_CLR, HW_RTC_CTRL_SFTRST);
187
188 loop = 0;
189 while ((RTC_RD(sc, HW_RTC_CTRL) & HW_RTC_CTRL_SFTRST) ||
190 (loop < RTC_SOFT_RST_LOOP))
191 loop++;
192
193 RTC_WR(sc, HW_RTC_CTRL_CLR, HW_RTC_CTRL_CLKGATE);
194
195 /* Wait until clock is in the NON-gated state. */
196 while (RTC_RD(sc, HW_RTC_CTRL) & HW_RTC_CTRL_CLKGATE);
197
198 return;
199 }
200