xref: /freebsd/sys/dev/iicbus/mux/pca954x.c (revision 1dfcff294e44d4b45813288ef4095c36abb22f0e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
5  * Copyright (c) 2020-2021 Andriy Gapon
6  * Copyright (c) 2022 Bjoern A. Zeeb
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 #include "opt_platform.h"
34 
35 #include <sys/param.h>
36 #include <sys/bus.h>
37 #include <sys/kernel.h>
38 #include <sys/module.h>
39 #include <sys/systm.h>
40 
41 #ifdef FDT
42 #include <dev/ofw/ofw_bus.h>
43 #include <dev/ofw/ofw_bus_subr.h>
44 #include <dev/ofw/openfirm.h>
45 #endif
46 
47 #include <dev/iicbus/iicbus.h>
48 #include <dev/iicbus/iiconf.h>
49 #include "iicbus_if.h"
50 #include "iicmux_if.h"
51 #include <dev/iicbus/mux/iicmux.h>
52 
53 enum pca954x_type {
54 	PCA954X_MUX,
55 	PCA954X_SW,
56 };
57 
58 struct pca954x_descr {
59 	const char 		*partname;
60 	const char		*description;
61 	enum pca954x_type	type;
62 	uint8_t			numchannels;
63 	uint8_t			enable;
64 };
65 
66 static struct pca954x_descr pca9540_descr = {
67 	.partname = "pca9540",
68 	.description = "PCA9540B I2C Mux",
69 	.type = PCA954X_MUX,
70 	.numchannels = 2,
71 	.enable = 0x04,
72 };
73 
74 static struct pca954x_descr pca9547_descr = {
75 	.partname = "pca9547",
76 	.description = "PCA9547 I2C Mux",
77 	.type = PCA954X_MUX,
78 	.numchannels = 8,
79 	.enable = 0x08,
80 };
81 
82 static struct pca954x_descr pca9548_descr = {
83 	.partname = "pca9548",
84 	.description = "PCA9548A I2C Switch",
85 	.type = PCA954X_SW,
86 	.numchannels = 8,
87 };
88 
89 #ifdef FDT
90 static struct ofw_compat_data compat_data[] = {
91 	{ "nxp,pca9540", (uintptr_t)&pca9540_descr },
92 	{ "nxp,pca9547", (uintptr_t)&pca9547_descr },
93 	{ "nxp,pca9548", (uintptr_t)&pca9548_descr },
94 	{ NULL, 0 },
95 };
96 #else
97 static struct pca954x_descr *part_descrs[] = {
98 	&pca9540_descr,
99 	&pca9547_descr,
100 	&pca9548_descr,
101 };
102 #endif
103 
104 struct pca954x_softc {
105 	struct iicmux_softc mux;
106 	const struct pca954x_descr *descr;
107 	uint8_t addr;
108 	bool idle_disconnect;
109 };
110 
111 static int
112 pca954x_bus_select(device_t dev, int busidx, struct iic_reqbus_data *rd)
113 {
114 	struct pca954x_softc *sc;
115 	struct iic_msg msg;
116 	int error;
117 	uint8_t busbits;
118 
119 	sc = device_get_softc(dev);
120 
121 	/*
122 	 * The iicmux caller ensures busidx is between 0 and the number of buses
123 	 * we passed to iicmux_init_softc(), no need for validation here.  If
124 	 * the fdt data has the idle_disconnect property we idle the bus by
125 	 * selecting no downstream buses, otherwise we just leave the current
126 	 * bus active.
127 	 */
128 	if (busidx == IICMUX_SELECT_IDLE) {
129 		if (sc->idle_disconnect)
130 			busbits = 0;
131 		else
132 			return (0);
133 	} else if (sc->descr->type == PCA954X_MUX) {
134 		uint8_t en;
135 
136 		en = sc->descr->enable;
137 		KASSERT(en > 0 && powerof2(en), ("%s: %s enable %#x "
138 		    "invalid\n", __func__, sc->descr->partname, en));
139 		busbits = en | (busidx & (en - 1));
140 	} else if (sc->descr->type == PCA954X_SW) {
141 		busbits = 1u << busidx;
142 	} else {
143 		panic("%s: %s: unsupported type %d\n",
144 		    __func__, sc->descr->partname, sc->descr->type);
145 	}
146 
147 	msg.slave = sc->addr;
148 	msg.flags = IIC_M_WR;
149 	msg.len = 1;
150 	msg.buf = &busbits;
151 	error = iicbus_transfer(dev, &msg, 1);
152 	return (error);
153 }
154 
155 static const struct pca954x_descr *
156 pca954x_find_chip(device_t dev)
157 {
158 #ifdef FDT
159 	const struct ofw_compat_data *compat;
160 
161 	if (!ofw_bus_status_okay(dev))
162 		return (NULL);
163 
164 	compat = ofw_bus_search_compatible(dev, compat_data);
165 	if (compat == NULL)
166 		return (NULL);
167 	return ((const struct pca954x_descr *)compat->ocd_data);
168 #else
169 	const char *type;
170 	int i;
171 
172 	if (resource_string_value(device_get_name(dev), device_get_unit(dev),
173 	    "chip_type", &type) == 0) {
174 		for (i = 0; i < nitems(part_descrs) - 1; ++i) {
175 			if (strcasecmp(type, part_descrs[i]->partname) == 0)
176 				return (part_descrs[i]);
177 		}
178 	}
179 	return (NULL);
180 #endif
181 }
182 
183 static int
184 pca954x_probe(device_t dev)
185 {
186 	const struct pca954x_descr *descr;
187 
188 	descr = pca954x_find_chip(dev);
189 	if (descr == NULL)
190 		return (ENXIO);
191 
192 	device_set_desc(dev, descr->description);
193 	return (BUS_PROBE_DEFAULT);
194 }
195 
196 static int
197 pca954x_attach(device_t dev)
198 {
199 	struct pca954x_softc *sc;
200 	const struct pca954x_descr *descr;
201 	int error;
202 
203 	sc = device_get_softc(dev);
204 	sc->addr = iicbus_get_addr(dev);
205 	sc->idle_disconnect = device_has_property(dev, "i2c-mux-idle-disconnect");
206 
207 	sc->descr = descr = pca954x_find_chip(dev);
208 	error = iicmux_attach(dev, device_get_parent(dev), descr->numchannels);
209 	if (error == 0)
210                 bus_generic_attach(dev);
211 
212 	return (error);
213 }
214 
215 static int
216 pca954x_detach(device_t dev)
217 {
218 	int error;
219 
220 	error = iicmux_detach(dev);
221 	return (error);
222 }
223 
224 static device_method_t pca954x_methods[] = {
225 	/* device methods */
226 	DEVMETHOD(device_probe,			pca954x_probe),
227 	DEVMETHOD(device_attach,		pca954x_attach),
228 	DEVMETHOD(device_detach,		pca954x_detach),
229 
230 	/* iicmux methods */
231 	DEVMETHOD(iicmux_bus_select,		pca954x_bus_select),
232 
233 	DEVMETHOD_END
234 };
235 
236 DEFINE_CLASS_1(pca954x, pca954x_driver, pca954x_methods,
237     sizeof(struct pca954x_softc), iicmux_driver);
238 DRIVER_MODULE(pca954x, iicbus, pca954x_driver, 0, 0);
239 
240 #ifdef FDT
241 DRIVER_MODULE(ofw_iicbus, pca954x, ofw_iicbus_driver, 0, 0);
242 #else
243 DRIVER_MODULE(iicbus, pca954x, iicbus_driver, 0, 0);
244 #endif
245 
246 MODULE_DEPEND(pca954x, iicmux, 1, 1, 1);
247 MODULE_DEPEND(pca954x, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
248 MODULE_VERSION(pca954x, 1);
249 
250 #ifdef FDT
251 IICBUS_FDT_PNP_INFO(compat_data);
252 #endif
253