1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) Andriy Gapon
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 FOR
19 * 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
29 #include <sys/cdefs.h>
30 #include "opt_platform.h"
31
32 #include <sys/param.h>
33 #include <sys/bus.h>
34 #include <sys/kernel.h>
35 #include <sys/module.h>
36 #include <sys/sysctl.h>
37 #include <sys/systm.h>
38
39 #include <machine/bus.h>
40
41 #include <dev/iicbus/iicbus.h>
42 #include <dev/iicbus/iiconf.h>
43
44 #ifdef FDT
45 #include <dev/ofw/ofw_bus.h>
46 #include <dev/ofw/ofw_bus_subr.h>
47 #endif
48
49 /*
50 * Driver for PCF8591 I2C 8-bit ADC and DAC.
51 */
52 #define CTRL_CH_SELECT_MASK 0x03
53 #define CTRL_AUTOINC_EN 0x04
54 #define CTRL_CH_CONFIG_MASK 0x30
55 #define CTRL_CH_CONFIG_4_SINGLE 0x00
56 #define CTRL_CH_CONFIG_3_DIFF 0x10
57 #define CTRL_CH_CONFIG_2_SINGLE_1_DIFF 0x20
58 #define CTRL_CH_CONFIG_2_DIFF 0x30
59 #define CTRL_OUTPUT_EN 0x40
60
61 struct pcf8591_softc {
62 device_t sc_dev;
63 int sc_ch_count;
64 uint8_t sc_addr;
65 uint8_t sc_cfg;
66 uint8_t sc_output;
67 };
68
69 #ifdef FDT
70 static struct ofw_compat_data compat_data[] = {
71 { "nxp,pcf8591", true },
72 { NULL, false }
73 };
74 #endif
75
76 static int
pcf8591_set_config(device_t dev)77 pcf8591_set_config(device_t dev)
78 {
79
80 struct iic_msg msg;
81 uint8_t data[2];
82 struct pcf8591_softc *sc;
83 int error;
84
85 sc = device_get_softc(dev);
86 data[0] = sc->sc_cfg;
87 data[1] = sc->sc_output;
88 msg.slave = sc->sc_addr;
89 msg.flags = IIC_M_WR;
90 msg.len = nitems(data);
91 msg.buf = data;
92
93 error = iicbus_transfer_excl(dev, &msg, 1, IIC_INTRWAIT);
94 return (error);
95 }
96
97 static int
pcf8591_get_reading(device_t dev,uint8_t * reading)98 pcf8591_get_reading(device_t dev, uint8_t *reading)
99 {
100 struct iic_msg msg;
101 struct pcf8591_softc *sc;
102 int error;
103
104 sc = device_get_softc(dev);
105
106 msg.slave = sc->sc_addr;
107 msg.flags = IIC_M_RD;
108 msg.len = 1;
109 msg.buf = reading;
110
111 error = iicbus_transfer_excl(dev, &msg, 1, IIC_INTRWAIT);
112 return (error);
113 }
114
115 static int
pcf8591_select_channel(device_t dev,int channel)116 pcf8591_select_channel(device_t dev, int channel)
117 {
118 struct pcf8591_softc *sc;
119 int error;
120 uint8_t unused;
121
122 sc = device_get_softc(dev);
123 if (channel >= sc->sc_ch_count)
124 return (EINVAL);
125 sc->sc_cfg &= ~CTRL_CH_SELECT_MASK;
126 sc->sc_cfg += channel;
127 error = pcf8591_set_config(dev);
128 if (error != 0)
129 return (error);
130
131 /*
132 * The next read is still for the old channel,
133 * so do it and discard.
134 */
135 error = pcf8591_get_reading(dev, &unused);
136 return (error);
137 }
138
139 static int
pcf8591_channel_sysctl(SYSCTL_HANDLER_ARGS)140 pcf8591_channel_sysctl(SYSCTL_HANDLER_ARGS)
141 {
142 device_t dev;
143 int error, channel, val;
144 uint8_t reading;
145
146 dev = arg1;
147 channel = arg2;
148
149 if (req->oldptr != NULL) {
150 error = pcf8591_select_channel(dev, channel);
151 if (error != 0)
152 return (EIO);
153 error = pcf8591_get_reading(dev, &reading);
154 if (error != 0)
155 return (EIO);
156 val = reading;
157 }
158 error = sysctl_handle_int(oidp, &val, 0, req);
159 return (error);
160 }
161
162 static void
pcf8591_start(void * arg)163 pcf8591_start(void *arg)
164 {
165 device_t dev;
166 struct pcf8591_softc *sc;
167 struct sysctl_ctx_list *ctx;
168 struct sysctl_oid *tree_node;
169 struct sysctl_oid_list *tree;
170 struct sysctl_oid *inputs_node;
171 struct sysctl_oid_list *inputs;
172
173 sc = arg;
174 dev = sc->sc_dev;
175
176 /*
177 * Set initial -- and, for the time being, fixed -- configuration.
178 * Channel auto-incrementi is disabled, although it could be more
179 * performant and precise for bulk channel queries.
180 * The inputs are configured as four single channels.
181 * The output is disabled.
182 */
183 sc->sc_cfg = 0;
184 sc->sc_output = 0;
185 sc->sc_ch_count = 4;
186 (void)pcf8591_set_config(dev);
187
188 ctx = device_get_sysctl_ctx(dev);
189 tree_node = device_get_sysctl_tree(dev);
190 tree = SYSCTL_CHILDREN(tree_node);
191
192 inputs_node = SYSCTL_ADD_NODE(ctx, tree, OID_AUTO, "inputs",
193 CTLTYPE_NODE, NULL, "Input channels");
194 inputs = SYSCTL_CHILDREN(inputs_node);
195 for (int i = 0; i < sc->sc_ch_count; i++) {
196 char buf[4];
197
198 snprintf(buf, sizeof(buf), "%d", i);
199 SYSCTL_ADD_PROC(ctx, inputs, OID_AUTO, buf,
200 CTLTYPE_INT | CTLFLAG_RD, dev, i,
201 pcf8591_channel_sysctl, "I", "Input level from 0 to 255 "
202 "(relative to Vref)");
203 }
204 }
205
206 static int
pcf8591_probe(device_t dev)207 pcf8591_probe(device_t dev)
208 {
209 #ifdef FDT
210 if (!ofw_bus_status_okay(dev))
211 return (ENXIO);
212 #endif
213 device_set_desc(dev, "PCF8591 8-bit ADC / DAC");
214 #ifdef FDT
215 if (ofw_bus_search_compatible(dev, compat_data)->ocd_data)
216 return (BUS_PROBE_GENERIC);
217 #endif
218 return (BUS_PROBE_NOWILDCARD);
219 }
220
221 static int
pcf8591_attach(device_t dev)222 pcf8591_attach(device_t dev)
223 {
224 struct pcf8591_softc *sc;
225
226 sc = device_get_softc(dev);
227 sc->sc_dev = dev;
228 sc->sc_addr = iicbus_get_addr(dev);
229
230 /*
231 * We have to wait until interrupts are enabled. Usually I2C read
232 * and write only works when the interrupts are available.
233 */
234 config_intrhook_oneshot(pcf8591_start, sc);
235 return (0);
236 }
237
238 static int
pcf8591_detach(device_t dev)239 pcf8591_detach(device_t dev)
240 {
241 return (0);
242 }
243
244 static device_method_t pcf8591_methods[] = {
245 /* Device interface */
246 DEVMETHOD(device_probe, pcf8591_probe),
247 DEVMETHOD(device_attach, pcf8591_attach),
248 DEVMETHOD(device_detach, pcf8591_detach),
249
250 DEVMETHOD_END
251 };
252
253 static driver_t pcf8591_driver = {
254 "pcf8591",
255 pcf8591_methods,
256 sizeof(struct pcf8591_softc)
257 };
258
259 DRIVER_MODULE(pcf8591, iicbus, pcf8591_driver, 0, 0);
260 MODULE_DEPEND(pcf8591, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
261 MODULE_VERSION(pcf8591, 1);
262 #ifdef FDT
263 IICBUS_FDT_PNP_INFO(compat_data);
264 #endif
265