1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2009 Oleksandr Tymoshenko <gonzo@freebsd.org>
5 * Copyright (c) 2010 Luiz Otavio O Souza
6 * Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
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#include "opt_platform.h"
32
33#include <sys/param.h>
34#include <sys/systm.h>
35#include <sys/bus.h>
36#include <sys/gpio.h>
37#include <sys/kernel.h>
38#include <sys/module.h>
39
40#include <dev/gpio/gpiobusvar.h>
41#include <dev/iicbus/iiconf.h>
42
43#include "gpiobus_if.h"
44#include "iicbb_if.h"
45
46#define	GPIOIIC_SCL_DFLT	0
47#define	GPIOIIC_SDA_DFLT	1
48#define	GPIOIIC_MIN_PINS	2
49
50struct gpioiic_softc
51{
52	device_t	dev;
53	gpio_pin_t	sclpin;
54	gpio_pin_t	sdapin;
55};
56
57#ifdef FDT
58
59#include <dev/ofw/ofw_bus.h>
60
61static struct ofw_compat_data compat_data[] = {
62	{"i2c-gpio",  true}, /* Standard devicetree compat string */
63	{"gpioiic",   true}, /* Deprecated old freebsd compat string */
64	{NULL,        false}
65};
66OFWBUS_PNP_INFO(compat_data);
67SIMPLEBUS_PNP_INFO(compat_data);
68
69static phandle_t
70gpioiic_get_node(device_t bus, device_t dev)
71{
72
73	/* Share our fdt node with iicbus so it can find its child nodes. */
74	return (ofw_bus_get_node(bus));
75}
76
77static int
78gpioiic_setup_fdt_pins(struct gpioiic_softc *sc)
79{
80	phandle_t node;
81	int err;
82
83	node = ofw_bus_get_node(sc->dev);
84
85	/*
86	 * Historically, we used the first two array elements of the gpios
87	 * property.  The modern bindings specify separate scl-gpios and
88	 * sda-gpios properties.  We cope with whichever is present.
89	 */
90	if (OF_hasprop(node, "gpios")) {
91		if ((err = gpio_pin_get_by_ofw_idx(sc->dev, node,
92		    GPIOIIC_SCL_DFLT, &sc->sclpin)) != 0) {
93			device_printf(sc->dev, "invalid gpios property\n");
94			return (err);
95		}
96		if ((err = gpio_pin_get_by_ofw_idx(sc->dev, node,
97		    GPIOIIC_SDA_DFLT, &sc->sdapin)) != 0) {
98			device_printf(sc->dev, "ivalid gpios property\n");
99			return (err);
100		}
101	} else {
102		if ((err = gpio_pin_get_by_ofw_property(sc->dev, node,
103		    "scl-gpios", &sc->sclpin)) != 0) {
104			device_printf(sc->dev, "missing scl-gpios property\n");
105			return (err);
106		}
107		if ((err = gpio_pin_get_by_ofw_property(sc->dev, node,
108		    "sda-gpios", &sc->sdapin)) != 0) {
109			device_printf(sc->dev, "missing sda-gpios property\n");
110			return (err);
111		}
112	}
113	return (0);
114}
115#endif /* FDT */
116
117static int
118gpioiic_setup_hinted_pins(struct gpioiic_softc *sc)
119{
120	device_t busdev;
121	const char *busname, *devname;
122	int err, numpins, sclnum, sdanum, unit;
123
124	devname = device_get_name(sc->dev);
125	unit = device_get_unit(sc->dev);
126	busdev = device_get_parent(sc->dev);
127
128	/*
129	 * If there is not an "at" hint naming our actual parent, then we
130	 * weren't instantiated as a child of gpiobus via hints, and we thus
131	 * can't access ivars that only exist for such children.
132	 */
133	if (resource_string_value(devname, unit, "at", &busname) != 0 ||
134	    (strcmp(busname, device_get_nameunit(busdev)) != 0 &&
135	     strcmp(busname, device_get_name(busdev)) != 0)) {
136		return (ENOENT);
137	}
138
139	/* Make sure there were hints for at least two pins. */
140	numpins = gpiobus_get_npins(sc->dev);
141	if (numpins < GPIOIIC_MIN_PINS) {
142#ifdef FDT
143		/*
144		 * Be silent when there are no hints on FDT systems; the FDT
145		 * data will provide the pin config (we'll whine if it doesn't).
146		 */
147		if (numpins == 0) {
148			return (ENOENT);
149		}
150#endif
151		device_printf(sc->dev,
152		    "invalid pins hint; it must contain at least %d pins\n",
153		    GPIOIIC_MIN_PINS);
154		return (EINVAL);
155	}
156
157	/*
158	 * Our parent bus has already parsed the pins hint and it will use that
159	 * info when we call gpio_pin_get_by_child_index().  But we have to
160	 * handle the scl/sda index hints that tell us which of the two pins is
161	 * the clock and which is the data.  They're optional, but if present
162	 * they must be a valid index (0 <= index < numpins).
163	 */
164	if ((err = resource_int_value(devname, unit, "scl", &sclnum)) != 0)
165		sclnum = GPIOIIC_SCL_DFLT;
166	else if (sclnum < 0 || sclnum >= numpins) {
167		device_printf(sc->dev, "invalid scl hint %d\n", sclnum);
168		return (EINVAL);
169	}
170	if ((err = resource_int_value(devname, unit, "sda", &sdanum)) != 0)
171		sdanum = GPIOIIC_SDA_DFLT;
172	else if (sdanum < 0 || sdanum >= numpins) {
173		device_printf(sc->dev, "invalid sda hint %d\n", sdanum);
174		return (EINVAL);
175	}
176
177	/* Allocate gpiobus_pin structs for the pins we found above. */
178	if ((err = gpio_pin_get_by_child_index(sc->dev, sclnum,
179	    &sc->sclpin)) != 0)
180		return (err);
181	if ((err = gpio_pin_get_by_child_index(sc->dev, sdanum,
182	    &sc->sdapin)) != 0)
183		return (err);
184
185	return (0);
186}
187
188static void
189gpioiic_setsda(device_t dev, int val)
190{
191	struct gpioiic_softc *sc = device_get_softc(dev);
192
193	if (val) {
194		gpio_pin_setflags(sc->sdapin, GPIO_PIN_INPUT);
195	} else {
196		gpio_pin_setflags(sc->sdapin,
197		    GPIO_PIN_OUTPUT | GPIO_PIN_OPENDRAIN);
198		gpio_pin_set_active(sc->sdapin, 0);
199	}
200}
201
202static void
203gpioiic_setscl(device_t dev, int val)
204{
205	struct gpioiic_softc *sc = device_get_softc(dev);
206
207	if (val) {
208		gpio_pin_setflags(sc->sclpin, GPIO_PIN_INPUT);
209	} else {
210		gpio_pin_setflags(sc->sclpin,
211		    GPIO_PIN_OUTPUT | GPIO_PIN_OPENDRAIN);
212		gpio_pin_set_active(sc->sclpin, 0);
213	}
214}
215
216static int
217gpioiic_getscl(device_t dev)
218{
219	struct gpioiic_softc *sc = device_get_softc(dev);
220	bool val;
221
222	gpio_pin_setflags(sc->sclpin, GPIO_PIN_INPUT);
223	gpio_pin_is_active(sc->sclpin, &val);
224	return (val);
225}
226
227static int
228gpioiic_getsda(device_t dev)
229{
230	struct gpioiic_softc *sc = device_get_softc(dev);
231	bool val;
232
233	gpio_pin_setflags(sc->sdapin, GPIO_PIN_INPUT);
234	gpio_pin_is_active(sc->sdapin, &val);
235	return (val);
236}
237
238static int
239gpioiic_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
240{
241	struct gpioiic_softc *sc = device_get_softc(dev);
242
243	/* Stop driving the bus pins. */
244	gpio_pin_setflags(sc->sdapin, GPIO_PIN_INPUT);
245	gpio_pin_setflags(sc->sclpin, GPIO_PIN_INPUT);
246
247	/* Indicate that we have no slave address (master mode). */
248	return (IIC_ENOADDR);
249}
250
251static void
252gpioiic_cleanup(struct gpioiic_softc *sc)
253{
254
255	device_delete_children(sc->dev);
256
257	if (sc->sclpin != NULL)
258		gpio_pin_release(sc->sclpin);
259
260	if (sc->sdapin != NULL)
261		gpio_pin_release(sc->sdapin);
262}
263
264static int
265gpioiic_probe(device_t dev)
266{
267	int rv;
268
269	/*
270	 * By default we only bid to attach if specifically added by our parent
271	 * (usually via hint.gpioiic.#.at=busname).  On FDT systems we bid as
272	 * the default driver based on being configured in the FDT data.
273	 */
274	rv = BUS_PROBE_NOWILDCARD;
275
276#ifdef FDT
277	if (ofw_bus_status_okay(dev) &&
278	    ofw_bus_search_compatible(dev, compat_data)->ocd_data)
279                rv = BUS_PROBE_DEFAULT;
280#endif
281
282	device_set_desc(dev, "GPIO I2C");
283
284	return (rv);
285}
286
287static int
288gpioiic_attach(device_t dev)
289{
290	struct gpioiic_softc *sc = device_get_softc(dev);
291	int err;
292
293	sc->dev = dev;
294
295	/* Acquire our gpio pins. */
296	err = gpioiic_setup_hinted_pins(sc);
297#ifdef FDT
298	if (err != 0)
299		err = gpioiic_setup_fdt_pins(sc);
300#endif
301	if (err != 0) {
302		device_printf(sc->dev, "no pins configured\n");
303		gpioiic_cleanup(sc);
304		return (ENXIO);
305	}
306
307	/*
308	 * Say what we came up with for pin config.
309	 * NB: in the !FDT case the controller driver might not be set up enough
310	 * for GPIO_GET_BUS() to work.  Also, our parent is the only gpiobus
311	 * that can provide our pins.
312	 */
313	device_printf(dev, "SCL pin: %s:%d, SDA pin: %s:%d\n",
314#ifdef FDT
315	    device_get_nameunit(GPIO_GET_BUS(sc->sclpin->dev)), sc->sclpin->pin,
316	    device_get_nameunit(GPIO_GET_BUS(sc->sdapin->dev)), sc->sdapin->pin);
317#else
318	    device_get_nameunit(device_get_parent(dev)), sc->sclpin->pin,
319	    device_get_nameunit(device_get_parent(dev)), sc->sdapin->pin);
320#endif
321
322	/* Add the bitbang driver as our only child; it will add iicbus. */
323	device_add_child(sc->dev, "iicbb", -1);
324	return (bus_generic_attach(dev));
325}
326
327static int
328gpioiic_detach(device_t dev)
329{
330	struct gpioiic_softc *sc = device_get_softc(dev);
331	int err;
332
333	if ((err = bus_generic_detach(dev)) != 0)
334		return (err);
335
336	gpioiic_cleanup(sc);
337
338	return (0);
339}
340
341static device_method_t gpioiic_methods[] = {
342	/* Device interface */
343	DEVMETHOD(device_probe,		gpioiic_probe),
344	DEVMETHOD(device_attach,	gpioiic_attach),
345	DEVMETHOD(device_detach,	gpioiic_detach),
346
347	/* iicbb interface */
348	DEVMETHOD(iicbb_setsda,		gpioiic_setsda),
349	DEVMETHOD(iicbb_setscl,		gpioiic_setscl),
350	DEVMETHOD(iicbb_getsda,		gpioiic_getsda),
351	DEVMETHOD(iicbb_getscl,		gpioiic_getscl),
352	DEVMETHOD(iicbb_reset,		gpioiic_reset),
353
354#ifdef FDT
355	/* OFW bus interface */
356	DEVMETHOD(ofw_bus_get_node,	gpioiic_get_node),
357#endif
358
359	DEVMETHOD_END
360};
361
362static driver_t gpioiic_driver = {
363	"gpioiic",
364	gpioiic_methods,
365	sizeof(struct gpioiic_softc),
366};
367
368DRIVER_MODULE(gpioiic, gpiobus, gpioiic_driver, 0, 0);
369DRIVER_MODULE(gpioiic, simplebus, gpioiic_driver, 0, 0);
370DRIVER_MODULE(iicbb, gpioiic, iicbb_driver, 0, 0);
371MODULE_DEPEND(gpioiic, iicbb, IICBB_MINVER, IICBB_PREFVER, IICBB_MAXVER);
372MODULE_DEPEND(gpioiic, gpiobus, 1, 1, 1);
373