1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1998, 2001 Nicolas Souchu, Marc Bouget
5 * All rights reserved.
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 AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 *
29 */
30
31 #include <sys/cdefs.h>
32 /*
33 * I2C Bit-Banging over parallel port
34 *
35 * See the Official Philips interface description in lpbb(4)
36 */
37
38 #include <sys/param.h>
39 #include <sys/bus.h>
40 #include <sys/lock.h>
41 #include <sys/kernel.h>
42 #include <sys/module.h>
43 #include <sys/mutex.h>
44 #include <sys/systm.h>
45 #include <sys/uio.h>
46
47 #include <dev/ppbus/ppbconf.h>
48 #include "ppbus_if.h"
49 #include <dev/ppbus/ppbio.h>
50
51 #include <dev/iicbus/iiconf.h>
52 #include <dev/iicbus/iicbus.h>
53
54 #include "iicbb_if.h"
55
56 static int lpbb_detect(device_t dev);
57
58 static void
lpbb_identify(driver_t * driver,device_t parent)59 lpbb_identify(driver_t *driver, device_t parent)
60 {
61
62 device_t dev;
63
64 dev = device_find_child(parent, "lpbb", -1);
65 if (!dev)
66 BUS_ADD_CHILD(parent, 0, "lpbb", -1);
67 }
68
69 static int
lpbb_probe(device_t dev)70 lpbb_probe(device_t dev)
71 {
72
73 /* Perhaps call this during identify instead? */
74 if (!lpbb_detect(dev))
75 return (ENXIO);
76
77 device_set_desc(dev, "Parallel I2C bit-banging interface");
78
79 return (0);
80 }
81
82 static int
lpbb_attach(device_t dev)83 lpbb_attach(device_t dev)
84 {
85 device_t bitbang;
86
87 /* add generic bit-banging code */
88 bitbang = device_add_child(dev, "iicbb", -1);
89 device_probe_and_attach(bitbang);
90
91 return (0);
92 }
93
94 static int
lpbb_callback(device_t dev,int index,caddr_t data)95 lpbb_callback(device_t dev, int index, caddr_t data)
96 {
97 device_t ppbus = device_get_parent(dev);
98 int error = 0;
99 int how;
100
101 switch (index) {
102 case IIC_REQUEST_BUS:
103 /* request the ppbus */
104 how = *(int *)data;
105 ppb_lock(ppbus);
106 error = ppb_request_bus(ppbus, dev, how);
107 ppb_unlock(ppbus);
108 break;
109
110 case IIC_RELEASE_BUS:
111 /* release the ppbus */
112 ppb_lock(ppbus);
113 error = ppb_release_bus(ppbus, dev);
114 ppb_unlock(ppbus);
115 break;
116
117 default:
118 error = EINVAL;
119 }
120
121 return (error);
122 }
123
124 #define SDA_out 0x80
125 #define SCL_out 0x08
126 #define SDA_in 0x80
127 #define SCL_in 0x08
128 #define ALIM 0x20
129 #define I2CKEY 0x50
130
131 /* Reset bus by setting SDA first and then SCL. */
132 static void
lpbb_reset_bus(device_t dev)133 lpbb_reset_bus(device_t dev)
134 {
135 device_t ppbus = device_get_parent(dev);
136
137 ppb_assert_locked(ppbus);
138 ppb_wdtr(ppbus, (u_char)~SDA_out);
139 ppb_wctr(ppbus, (u_char)(ppb_rctr(ppbus) | SCL_out));
140 }
141
142 static int
lpbb_getscl(device_t dev)143 lpbb_getscl(device_t dev)
144 {
145 device_t ppbus = device_get_parent(dev);
146 int rval;
147
148 ppb_lock(ppbus);
149 rval = ((ppb_rstr(ppbus) & SCL_in) == SCL_in);
150 ppb_unlock(ppbus);
151 return (rval);
152 }
153
154 static int
lpbb_getsda(device_t dev)155 lpbb_getsda(device_t dev)
156 {
157 device_t ppbus = device_get_parent(dev);
158 int rval;
159
160 ppb_lock(ppbus);
161 rval = ((ppb_rstr(ppbus) & SDA_in) == SDA_in);
162 ppb_unlock(ppbus);
163 return (rval);
164 }
165
166 static void
lpbb_setsda(device_t dev,int val)167 lpbb_setsda(device_t dev, int val)
168 {
169 device_t ppbus = device_get_parent(dev);
170
171 ppb_lock(ppbus);
172 if (val == 0)
173 ppb_wdtr(ppbus, (u_char)SDA_out);
174 else
175 ppb_wdtr(ppbus, (u_char)~SDA_out);
176 ppb_unlock(ppbus);
177 }
178
179 static void
lpbb_setscl(device_t dev,int val)180 lpbb_setscl(device_t dev, int val)
181 {
182 device_t ppbus = device_get_parent(dev);
183
184 ppb_lock(ppbus);
185 if (val == 0)
186 ppb_wctr(ppbus, (u_char)(ppb_rctr(ppbus) & ~SCL_out));
187 else
188 ppb_wctr(ppbus, (u_char)(ppb_rctr(ppbus) | SCL_out));
189 ppb_unlock(ppbus);
190 }
191
192 static int
lpbb_detect(device_t dev)193 lpbb_detect(device_t dev)
194 {
195 device_t ppbus = device_get_parent(dev);
196
197 ppb_lock(ppbus);
198 if (ppb_request_bus(ppbus, dev, PPB_DONTWAIT)) {
199 ppb_unlock(ppbus);
200 device_printf(dev, "can't allocate ppbus\n");
201 return (0);
202 }
203
204 lpbb_reset_bus(dev);
205
206 if ((ppb_rstr(ppbus) & I2CKEY) ||
207 ((ppb_rstr(ppbus) & ALIM) != ALIM)) {
208 ppb_release_bus(ppbus, dev);
209 ppb_unlock(ppbus);
210 return (0);
211 }
212
213 ppb_release_bus(ppbus, dev);
214 ppb_unlock(ppbus);
215
216 return (1);
217 }
218
219 static int
lpbb_reset(device_t dev,u_char speed,u_char addr,u_char * oldaddr)220 lpbb_reset(device_t dev, u_char speed, u_char addr, u_char * oldaddr)
221 {
222 device_t ppbus = device_get_parent(dev);
223
224 ppb_lock(ppbus);
225 if (ppb_request_bus(ppbus, dev, PPB_DONTWAIT)) {
226 ppb_unlock(ppbus);
227 device_printf(dev, "can't allocate ppbus\n");
228 return (0);
229 }
230
231 lpbb_reset_bus(dev);
232
233 ppb_release_bus(ppbus, dev);
234 ppb_unlock(ppbus);
235
236 return (IIC_ENOADDR);
237 }
238
239 static device_method_t lpbb_methods[] = {
240 /* device interface */
241 DEVMETHOD(device_identify, lpbb_identify),
242 DEVMETHOD(device_probe, lpbb_probe),
243 DEVMETHOD(device_attach, lpbb_attach),
244
245 /* iicbb interface */
246 DEVMETHOD(iicbb_callback, lpbb_callback),
247 DEVMETHOD(iicbb_setsda, lpbb_setsda),
248 DEVMETHOD(iicbb_setscl, lpbb_setscl),
249 DEVMETHOD(iicbb_getsda, lpbb_getsda),
250 DEVMETHOD(iicbb_getscl, lpbb_getscl),
251 DEVMETHOD(iicbb_reset, lpbb_reset),
252
253 DEVMETHOD_END
254 };
255
256 static driver_t lpbb_driver = {
257 "lpbb",
258 lpbb_methods,
259 1,
260 };
261
262 DRIVER_MODULE(lpbb, ppbus, lpbb_driver, 0, 0);
263 DRIVER_MODULE(iicbb, lpbb, iicbb_driver, 0, 0);
264 MODULE_DEPEND(lpbb, ppbus, 1, 1, 1);
265 MODULE_DEPEND(lpbb, iicbb, IICBB_MINVER, IICBB_PREFVER, IICBB_MAXVER);
266 MODULE_VERSION(lpbb, 1);
267