1 /* $OpenBSD: iicmux.c,v 1.2 2022/04/06 18:59:28 naddy Exp $ */
2 /*
3 * Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include <sys/param.h>
19 #include <sys/systm.h>
20 #include <sys/malloc.h>
21 #include <sys/device.h>
22
23 #include <machine/bus.h>
24 #include <machine/fdt.h>
25
26 #define _I2C_PRIVATE
27 #include <dev/i2c/i2cvar.h>
28
29 #include <dev/ofw/openfirm.h>
30 #include <dev/ofw/ofw_misc.h>
31 #include <dev/ofw/ofw_pinctrl.h>
32
33 #define IICMUX_MAX_CHANNELS 4
34
35 struct iicmux_bus {
36 struct iicmux_softc *pb_sc;
37 int pb_node;
38 int pb_channel;
39 struct i2c_controller pb_ic;
40 struct i2c_bus pb_ib;
41 struct device *pb_iic;
42 };
43
44 struct iicmux_softc {
45 struct device sc_dev;
46 i2c_tag_t sc_tag;
47
48 int sc_node;
49 int sc_channel;
50 int sc_nchannel;
51 struct iicmux_bus sc_bus[IICMUX_MAX_CHANNELS];
52 const char *sc_busnames[IICMUX_MAX_CHANNELS];
53 struct rwlock sc_lock;
54
55 int sc_enable;
56 };
57
58 int iicmux_match(struct device *, void *, void *);
59 void iicmux_attach(struct device *, struct device *, void *);
60
61 const struct cfattach iicmux_ca = {
62 sizeof(struct iicmux_softc), iicmux_match, iicmux_attach
63 };
64
65 struct cfdriver iicmux_cd = {
66 NULL, "iicmux", DV_DULL
67 };
68
69 int iicmux_acquire_bus(void *, int);
70 void iicmux_release_bus(void *, int);
71 int iicmux_exec(void *, i2c_op_t, i2c_addr_t, const void *, size_t,
72 void *, size_t, int);
73 void iicmux_bus_scan(struct device *, struct i2cbus_attach_args *, void *);
74
75 int
iicmux_match(struct device * parent,void * match,void * aux)76 iicmux_match(struct device *parent, void *match, void *aux)
77 {
78 struct fdt_attach_args *faa = aux;
79
80 return OF_is_compatible(faa->fa_node, "i2c-mux-pinctrl");
81 }
82
83 void
iicmux_attach(struct device * parent,struct device * self,void * aux)84 iicmux_attach(struct device *parent, struct device *self, void *aux)
85 {
86 struct iicmux_softc *sc = (struct iicmux_softc *)self;
87 struct fdt_attach_args *faa = aux;
88 int node = faa->fa_node;
89 uint32_t phandle;
90 char *names;
91 char *name;
92 char *end;
93 int len;
94
95 sc->sc_channel = -1; /* unknown */
96 rw_init(&sc->sc_lock, sc->sc_dev.dv_xname);
97
98 phandle = OF_getpropint(node, "i2c-parent", 0);
99 sc->sc_tag = i2c_byphandle(phandle);
100 if (sc->sc_tag == NULL) {
101 printf(": can't find parent bus\n");
102 return;
103 }
104
105 len = OF_getproplen(node, "pinctrl-names");
106 if (len <= 0) {
107 printf(": no channels\n");
108 return;
109 }
110
111 names = malloc(len, M_DEVBUF, M_WAITOK);
112 OF_getprop(node, "pinctrl-names", names, len);
113 end = names + len;
114 name = names;
115 while (name < end) {
116 if (strcmp(name, "idle") == 0)
117 break;
118
119 if (sc->sc_nchannel >= IICMUX_MAX_CHANNELS) {
120 printf(": too many channels\n");
121 free(names, M_DEVBUF, len);
122 return;
123 }
124
125 sc->sc_busnames[sc->sc_nchannel] = name;
126 name += strlen(name) + 1;
127 sc->sc_nchannel++;
128 }
129
130 printf("\n");
131
132 sc->sc_node = node;
133 for (node = OF_child(node); node; node = OF_peer(node)) {
134 struct i2cbus_attach_args iba;
135 struct iicmux_bus *pb;
136 uint32_t channel;
137
138 channel = OF_getpropint(node, "reg", -1);
139 if (channel >= sc->sc_nchannel)
140 continue;
141
142 pb = &sc->sc_bus[channel];
143 pb->pb_sc = sc;
144 pb->pb_node = node;
145 pb->pb_channel = channel;
146 pb->pb_ic.ic_cookie = pb;
147 pb->pb_ic.ic_acquire_bus = iicmux_acquire_bus;
148 pb->pb_ic.ic_release_bus = iicmux_release_bus;
149 pb->pb_ic.ic_exec = iicmux_exec;
150
151 /* Configure the child busses. */
152 memset(&iba, 0, sizeof(iba));
153 iba.iba_name = "iic";
154 iba.iba_tag = &pb->pb_ic;
155 iba.iba_bus_scan = iicmux_bus_scan;
156 iba.iba_bus_scan_arg = &pb->pb_node;
157
158 config_found(&sc->sc_dev, &iba, iicbus_print);
159
160 pb->pb_ib.ib_node = node;
161 pb->pb_ib.ib_ic = &pb->pb_ic;
162 i2c_register(&pb->pb_ib);
163 }
164 }
165
166 int
iicmux_set_channel(struct iicmux_softc * sc,int channel,int flags)167 iicmux_set_channel(struct iicmux_softc *sc, int channel, int flags)
168 {
169 int error;
170
171 if (channel < -1 || channel >= sc->sc_nchannel)
172 return ENXIO;
173
174 if (sc->sc_channel == channel)
175 return 0;
176
177 error = pinctrl_byname(sc->sc_node, sc->sc_busnames[channel]);
178 if (error == 0)
179 sc->sc_channel = channel;
180
181 return error ? EIO : 0;
182 }
183
184 int
iicmux_acquire_bus(void * cookie,int flags)185 iicmux_acquire_bus(void *cookie, int flags)
186 {
187 struct iicmux_bus *pb = cookie;
188 struct iicmux_softc *sc = pb->pb_sc;
189 int rwflags = RW_WRITE;
190 int error;
191
192 if (flags & I2C_F_POLL)
193 rwflags |= RW_NOSLEEP;
194
195 error = rw_enter(&sc->sc_lock, rwflags);
196 if (error)
197 return error;
198
199 /* Acquire parent bus. */
200 error = iic_acquire_bus(sc->sc_tag, flags);
201 if (error) {
202 rw_exit_write(&sc->sc_lock);
203 return error;
204 }
205
206 error = iicmux_set_channel(sc, pb->pb_channel, flags);
207 if (error) {
208 iic_release_bus(sc->sc_tag, flags);
209 rw_exit_write(&sc->sc_lock);
210 return error;
211 }
212
213 return 0;
214 }
215
216 void
iicmux_release_bus(void * cookie,int flags)217 iicmux_release_bus(void *cookie, int flags)
218 {
219 struct iicmux_bus *pb = cookie;
220 struct iicmux_softc *sc = pb->pb_sc;
221
222 if (pinctrl_byname(sc->sc_node, "idle") == 0)
223 sc->sc_channel = -1;
224
225 /* Release parent bus. */
226 iic_release_bus(sc->sc_tag, flags);
227 rw_exit_write(&sc->sc_lock);
228 }
229
230 int
iicmux_exec(void * cookie,i2c_op_t op,i2c_addr_t addr,const void * cmd,size_t cmdlen,void * buf,size_t buflen,int flags)231 iicmux_exec(void *cookie, i2c_op_t op, i2c_addr_t addr, const void *cmd,
232 size_t cmdlen, void *buf, size_t buflen, int flags)
233 {
234 struct iicmux_bus *pb = cookie;
235 struct iicmux_softc *sc = pb->pb_sc;
236
237 rw_assert_wrlock(&sc->sc_lock);
238
239 /* Issue the transaction on the parent bus. */
240 return iic_exec(sc->sc_tag, op, addr, cmd, cmdlen, buf, buflen, flags);
241 }
242
243 void
iicmux_bus_scan(struct device * self,struct i2cbus_attach_args * iba,void * arg)244 iicmux_bus_scan(struct device *self, struct i2cbus_attach_args *iba, void *arg)
245 {
246 int iba_node = *(int *)arg;
247 struct i2c_attach_args ia;
248 char name[32];
249 uint32_t reg[1];
250 int node;
251
252 for (node = OF_child(iba_node); node; node = OF_peer(node)) {
253 memset(name, 0, sizeof(name));
254 memset(reg, 0, sizeof(reg));
255
256 if (OF_getprop(node, "compatible", name, sizeof(name)) == -1)
257 continue;
258 if (name[0] == '\0')
259 continue;
260
261 if (OF_getprop(node, "reg", ®, sizeof(reg)) != sizeof(reg))
262 continue;
263
264 memset(&ia, 0, sizeof(ia));
265 ia.ia_tag = iba->iba_tag;
266 ia.ia_addr = bemtoh32(®[0]);
267 ia.ia_name = name;
268 ia.ia_cookie = &node;
269 config_found(self, &ia, iic_print);
270 }
271 }
272