1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/cdefs.h>
29 #include "opt_platform.h"
30
31 #include <sys/param.h>
32 #include <sys/bus.h>
33 #include <sys/kernel.h>
34 #include <sys/module.h>
35 #include <sys/systm.h>
36
37 #include <dev/iicbus/iicbus.h>
38 #include <dev/iicbus/iiconf.h>
39 #include "iicbus_if.h"
40 #include "iicmux_if.h"
41
42 static struct chip_info {
43 const char *partname;
44 const char *description;
45 int numchannels;
46 } chip_infos[] = {
47 {"ltc4305", "LTC4305 I2C Mux", 2},
48 {"ltc4306", "LTC4306 I2C Mux", 4},
49 };
50 #define CHIP_NONE (-1)
51 #define CHIP_LTC4305 0
52 #define CHIP_LTC4306 1
53
54 #ifdef FDT
55 #include <dev/ofw/ofw_bus.h>
56 #include <dev/ofw/ofw_bus_subr.h>
57 #include <dev/ofw/openfirm.h>
58
59 static struct ofw_compat_data compat_data[] = {
60 {"lltc,ltc4305", CHIP_LTC4305},
61 {"lltc,ltc4306", CHIP_LTC4306},
62 {NULL, CHIP_NONE}
63 };
64 IICBUS_FDT_PNP_INFO(compat_data);
65 #endif
66
67 #include <dev/iicbus/mux/iicmux.h>
68
69 struct ltc430x_softc {
70 struct iicmux_softc mux;
71 bool idle_disconnect;
72 };
73
74 /*
75 * The datasheet doesn't name the registers, it calls them control register 0-3.
76 */
77 #define LTC430X_CTLREG_0 0
78 #define LTC430X_CTLREG_1 1
79 #define LTC430X_CTLREG_2 2
80 #define LTC430X_CR2_ENABLE_MW (1u << 3) /* Enable mass write address. */
81 #define LTC430X_CTLREG_3 3
82
83 static int
ltc430x_bus_select(device_t dev,int busidx,struct iic_reqbus_data * rd)84 ltc430x_bus_select(device_t dev, int busidx, struct iic_reqbus_data *rd)
85 {
86 struct ltc430x_softc *sc = device_get_softc(dev);
87 uint8_t busbits;
88
89 /*
90 * The iicmux caller ensures busidx is between 0 and the number of buses
91 * we passed to iicmux_init_softc(), no need for validation here. If
92 * the fdt data has the idle_disconnect property we idle the bus by
93 * selecting no downstream buses, otherwise we just leave the current
94 * bus active. The upper bits of control register 3 activate the
95 * downstream buses; bit 7 is the first bus, bit 6 the second, etc.
96 */
97 if (busidx == IICMUX_SELECT_IDLE) {
98 if (sc->idle_disconnect)
99 busbits = 0;
100 else
101 return (0);
102 } else {
103 busbits = 1u << (7 - busidx);
104 }
105
106 /*
107 * We have to add the IIC_RECURSIVE flag because the iicmux core has
108 * already reserved the bus for us, and iicdev_writeto() is going to try
109 * to reserve it again, which is allowed with the recursive flag.
110 */
111 return (iicdev_writeto(dev, LTC430X_CTLREG_3, &busbits, sizeof(busbits),
112 rd->flags | IIC_RECURSIVE));
113 }
114
115 static int
ltc430x_find_chiptype(device_t dev)116 ltc430x_find_chiptype(device_t dev)
117 {
118 #ifdef FDT
119 return (ofw_bus_search_compatible(dev, compat_data)->ocd_data);
120 #else
121 const char *type;
122 int i;
123
124 if (resource_string_value(device_get_name(dev), device_get_unit(dev),
125 "chip_type", &type) == 0) {
126 for (i = 0; i < nitems(chip_infos); ++i) {
127 if (strcasecmp(type, chip_infos[i].partname) == 0) {
128 return (i);
129 }
130 }
131 }
132 return (CHIP_NONE);
133 #endif
134 }
135
136 static int
ltc430x_probe(device_t dev)137 ltc430x_probe(device_t dev)
138 {
139 int type;
140
141 #ifdef FDT
142 if (!ofw_bus_status_okay(dev))
143 return (ENXIO);
144 #endif
145
146 type = ltc430x_find_chiptype(dev);
147 if (type == CHIP_NONE)
148 return (ENXIO);
149
150 device_set_desc(dev, chip_infos[type].description);
151
152 return (BUS_PROBE_DEFAULT);
153 }
154
155 static int
ltc430x_attach(device_t dev)156 ltc430x_attach(device_t dev)
157 {
158 struct ltc430x_softc *sc __unused;
159 int chip, err, numchan, val;
160 uint8_t busbits, ctlreg2;
161
162 sc = device_get_softc(dev);
163
164 busbits = 0;
165 ctlreg2 = LTC430X_CR2_ENABLE_MW;
166
167 /*
168 * Check for the idle-disconnect and ctlreg2 options, first in FDT data,
169 * then allow them to be overridden by hints data.
170 */
171 #ifdef FDT
172 phandle_t node;
173
174 node = ofw_bus_get_node(dev);
175 sc->idle_disconnect = OF_hasprop(node, "i2c-mux-idle-disconnect");
176
177 if (OF_getprop(node, "freebsd,ctlreg2", &val, sizeof(val)) > 0) {
178 ctlreg2 = val;
179 }
180 #endif
181
182 if (resource_int_value(device_get_name(dev), device_get_unit(dev),
183 "idle_disconnect", &val) == 0) {
184 sc->idle_disconnect = val;
185 }
186
187 if (resource_int_value(device_get_name(dev), device_get_unit(dev),
188 "ctlreg2", &val) == 0) {
189 ctlreg2 = val;
190 }
191
192 /* We found the chip type when probing, so now it "can't fail". */
193 if ((chip = ltc430x_find_chiptype(dev)) == CHIP_NONE) {
194 device_printf(dev, "impossible: can't identify chip type\n");
195 return (ENXIO);
196 }
197 numchan = chip_infos[chip].numchannels;
198
199 /* Set control reg 2 with configured (or default) values. */
200 iicdev_writeto(dev, LTC430X_CTLREG_2, &ctlreg2, sizeof(ctlreg2),
201 IIC_WAIT);
202
203 /* If configured for idle-disconnect, ensure we start disconnected. */
204 if (sc->idle_disconnect) {
205 iicdev_writeto(dev, LTC430X_CTLREG_3, &busbits, sizeof(busbits),
206 IIC_WAIT);
207 }
208
209 /*
210 * Invoke the iicmux framework's attach code, and if it succeeds, invoke
211 * the probe and attach code of any child iicbus instances it added.
212 */
213 if ((err = iicmux_attach(dev, device_get_parent(dev), numchan)) == 0)
214 bus_generic_attach(dev);
215
216 return (err);
217 }
218
219 static int
ltc430x_detach(device_t dev)220 ltc430x_detach(device_t dev)
221 {
222 int err;
223
224 if ((err = iicmux_detach(dev)) != 0)
225 return (err);
226
227 return (0);
228 }
229
230 static device_method_t ltc430x_methods[] = {
231 /* device methods */
232 DEVMETHOD(device_probe, ltc430x_probe),
233 DEVMETHOD(device_attach, ltc430x_attach),
234 DEVMETHOD(device_detach, ltc430x_detach),
235
236 /* iicmux methods */
237 DEVMETHOD(iicmux_bus_select, ltc430x_bus_select),
238
239 DEVMETHOD_END
240 };
241
242 DEFINE_CLASS_1(ltc430x, ltc430x_driver, ltc430x_methods,
243 sizeof(struct ltc430x_softc), iicmux_driver);
244 DRIVER_MODULE(ltc430x, iicbus, ltc430x_driver, 0, 0);
245
246 #ifdef FDT
247 DRIVER_MODULE(ofw_iicbus, ltc430x, ofw_iicbus_driver, 0, 0);
248 #else
249 DRIVER_MODULE(iicbus, ltc430x, iicbus_driver, 0, 0);
250 #endif
251
252 MODULE_DEPEND(ltc430x, iicmux, 1, 1, 1);
253 MODULE_DEPEND(ltc430x, iicbus, 1, 1, 1);
254
255