xref: /freebsd/sys/dev/iicbus/iic.c (revision 10ff414c14eef433d8157f0c17904d740693933b) 
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1998, 2001 Nicolas Souchu
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  *
30  */
31 #include <sys/param.h>
32 #include <sys/bus.h>
33 #include <sys/conf.h>
34 #include <sys/fcntl.h>
35 #include <sys/lock.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/module.h>
39 #include <sys/sx.h>
40 #include <sys/systm.h>
41 #include <sys/uio.h>
42 #include <sys/errno.h>
43 
44 #include <dev/iicbus/iiconf.h>
45 #include <dev/iicbus/iicbus.h>
46 #include <dev/iicbus/iic.h>
47 
48 #include "iicbus_if.h"
49 
50 struct iic_softc {
51 	device_t sc_dev;
52 	struct cdev *sc_devnode;
53 };
54 
55 struct iic_cdevpriv {
56 	struct sx lock;
57 	struct iic_softc *sc;
58 	bool started;
59 	uint8_t addr;
60 };
61 
62 
63 #define	IIC_LOCK(cdp)			sx_xlock(&(cdp)->lock)
64 #define	IIC_UNLOCK(cdp)			sx_xunlock(&(cdp)->lock)
65 
66 static MALLOC_DEFINE(M_IIC, "iic", "I2C device data");
67 
68 static int iic_probe(device_t);
69 static int iic_attach(device_t);
70 static int iic_detach(device_t);
71 static void iic_identify(driver_t *driver, device_t parent);
72 static void iicdtor(void *data);
73 static int iicuio_move(struct iic_cdevpriv *priv, struct uio *uio, int last);
74 static int iicuio(struct cdev *dev, struct uio *uio, int ioflag);
75 static int iicrdwr(struct iic_cdevpriv *priv, struct iic_rdwr_data *d, int flags);
76 
77 static devclass_t iic_devclass;
78 
79 static device_method_t iic_methods[] = {
80 	/* device interface */
81 	DEVMETHOD(device_identify,	iic_identify),
82 	DEVMETHOD(device_probe,		iic_probe),
83 	DEVMETHOD(device_attach,	iic_attach),
84 	DEVMETHOD(device_detach,	iic_detach),
85 
86 	/* iicbus interface */
87 	DEVMETHOD(iicbus_intr,		iicbus_generic_intr),
88 
89 	{ 0, 0 }
90 };
91 
92 static driver_t iic_driver = {
93 	"iic",
94 	iic_methods,
95 	sizeof(struct iic_softc),
96 };
97 
98 static	d_open_t	iicopen;
99 static	d_ioctl_t	iicioctl;
100 
101 static struct cdevsw iic_cdevsw = {
102 	.d_version =	D_VERSION,
103 	.d_open =	iicopen,
104 	.d_read =	iicuio,
105 	.d_write =	iicuio,
106 	.d_ioctl =	iicioctl,
107 	.d_name =	"iic",
108 };
109 
110 static void
111 iic_identify(driver_t *driver, device_t parent)
112 {
113 
114 	if (device_find_child(parent, "iic", -1) == NULL)
115 		BUS_ADD_CHILD(parent, 0, "iic", -1);
116 }
117 
118 static int
119 iic_probe(device_t dev)
120 {
121 	if (iicbus_get_addr(dev) > 0)
122 		return (ENXIO);
123 
124 	device_set_desc(dev, "I2C generic I/O");
125 
126 	return (0);
127 }
128 
129 static int
130 iic_attach(device_t dev)
131 {
132 	struct iic_softc *sc;
133 
134 	sc = device_get_softc(dev);
135 	sc->sc_dev = dev;
136 	sc->sc_devnode = make_dev(&iic_cdevsw, device_get_unit(dev),
137 			UID_ROOT, GID_WHEEL,
138 			0600, "iic%d", device_get_unit(dev));
139 	if (sc->sc_devnode == NULL) {
140 		device_printf(dev, "failed to create character device\n");
141 		return (ENXIO);
142 	}
143 	sc->sc_devnode->si_drv1 = sc;
144 
145 	return (0);
146 }
147 
148 static int
149 iic_detach(device_t dev)
150 {
151 	struct iic_softc *sc;
152 
153 	sc = device_get_softc(dev);
154 
155 	if (sc->sc_devnode)
156 		destroy_dev(sc->sc_devnode);
157 
158 	return (0);
159 }
160 
161 static int
162 iicopen(struct cdev *dev, int flags, int fmt, struct thread *td)
163 {
164 	struct iic_cdevpriv *priv;
165 	int error;
166 
167 	priv = malloc(sizeof(*priv), M_IIC, M_WAITOK | M_ZERO);
168 
169 	sx_init(&priv->lock, "iic");
170 	priv->sc = dev->si_drv1;
171 
172 	error = devfs_set_cdevpriv(priv, iicdtor);
173 	if (error != 0)
174 		free(priv, M_IIC);
175 
176 	return (error);
177 }
178 
179 static void
180 iicdtor(void *data)
181 {
182 	device_t iicdev, parent;
183 	struct iic_cdevpriv *priv;
184 
185 	priv = data;
186 	KASSERT(priv != NULL, ("iic cdevpriv should not be NULL!"));
187 
188 	iicdev = priv->sc->sc_dev;
189 	parent = device_get_parent(iicdev);
190 
191 	if (priv->started) {
192 		iicbus_stop(parent);
193 		iicbus_reset(parent, IIC_UNKNOWN, 0, NULL);
194 		iicbus_release_bus(parent, iicdev);
195 	}
196 
197 	sx_destroy(&priv->lock);
198 	free(priv, M_IIC);
199 }
200 
201 static int
202 iicuio_move(struct iic_cdevpriv *priv, struct uio *uio, int last)
203 {
204 	device_t parent;
205 	int error, num_bytes, transferred_bytes, written_bytes;
206 	char buffer[128];
207 
208 	parent = device_get_parent(priv->sc->sc_dev);
209 	error = 0;
210 
211 	/*
212 	 * We can only transfer up to sizeof(buffer) bytes in 1 shot, so loop until
213 	 * everything has been transferred.
214 	*/
215 	while ((error == 0) && (uio->uio_resid > 0)) {
216 
217 		num_bytes = MIN(uio->uio_resid, sizeof(buffer));
218 		transferred_bytes = 0;
219 
220 		if (uio->uio_rw == UIO_WRITE) {
221 			error = uiomove(buffer, num_bytes, uio);
222 
223 			while ((error == 0) && (transferred_bytes < num_bytes)) {
224 				written_bytes = 0;
225 				error = iicbus_write(parent, &buffer[transferred_bytes],
226 				    num_bytes - transferred_bytes, &written_bytes, 0);
227 				transferred_bytes += written_bytes;
228 			}
229 
230 		} else if (uio->uio_rw == UIO_READ) {
231 			error = iicbus_read(parent, buffer,
232 			    num_bytes, &transferred_bytes,
233 			    ((uio->uio_resid <= sizeof(buffer)) ? last : 0), 0);
234 			if (error == 0)
235 				error = uiomove(buffer, transferred_bytes, uio);
236 		}
237 	}
238 
239 	return (error);
240 }
241 
242 static int
243 iicuio(struct cdev *dev, struct uio *uio, int ioflag)
244 {
245 	device_t parent;
246 	struct iic_cdevpriv *priv;
247 	int error;
248 	uint8_t addr;
249 
250 	priv = NULL;
251 	error = devfs_get_cdevpriv((void**)&priv);
252 
253 	if (error != 0)
254 		return (error);
255 	KASSERT(priv != NULL, ("iic cdevpriv should not be NULL!"));
256 
257 	IIC_LOCK(priv);
258 	if (priv->started || (priv->addr == 0)) {
259 		IIC_UNLOCK(priv);
260 		return (ENXIO);
261 	}
262 	parent = device_get_parent(priv->sc->sc_dev);
263 
264 	error = iicbus_request_bus(parent, priv->sc->sc_dev,
265 	    (ioflag & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));
266 	if (error != 0) {
267 		IIC_UNLOCK(priv);
268 		return (error);
269 	}
270 
271 	if (uio->uio_rw == UIO_READ)
272 		addr = priv->addr | LSB;
273 	else
274 		addr = priv->addr & ~LSB;
275 
276 	error = iicbus_start(parent, addr, 0);
277 	if (error != 0)
278 	{
279 		iicbus_release_bus(parent, priv->sc->sc_dev);
280 		IIC_UNLOCK(priv);
281 		return (error);
282 	}
283 
284 	error = iicuio_move(priv, uio, IIC_LAST_READ);
285 
286 	iicbus_stop(parent);
287 	iicbus_release_bus(parent, priv->sc->sc_dev);
288 	IIC_UNLOCK(priv);
289 	return (error);
290 }
291 
292 static int
293 iicrdwr(struct iic_cdevpriv *priv, struct iic_rdwr_data *d, int flags)
294 {
295 	struct iic_msg *buf, *m;
296 	void **usrbufs;
297 	device_t iicdev, parent;
298 	int error;
299 	uint32_t i;
300 
301 	iicdev = priv->sc->sc_dev;
302 	parent = device_get_parent(iicdev);
303 	error = 0;
304 
305 	if (d->nmsgs > IIC_RDRW_MAX_MSGS)
306 		return (EINVAL);
307 
308 	buf = malloc(sizeof(*d->msgs) * d->nmsgs, M_IIC, M_WAITOK);
309 
310 	error = copyin(d->msgs, buf, sizeof(*d->msgs) * d->nmsgs);
311 	if (error != 0) {
312 		free(buf, M_IIC);
313 		return (error);
314 	}
315 
316 	/* Alloc kernel buffers for userland data, copyin write data */
317 	usrbufs = malloc(sizeof(void *) * d->nmsgs, M_IIC, M_WAITOK | M_ZERO);
318 
319 	for (i = 0; i < d->nmsgs; i++) {
320 		m = &(buf[i]);
321 		usrbufs[i] = m->buf;
322 
323 		/*
324 		 * At least init the buffer to NULL so we can safely free() it later.
325 		 * If the copyin() to buf failed, don't try to malloc bogus m->len.
326 		 */
327 		m->buf = NULL;
328 		if (error != 0)
329 			continue;
330 
331 		/* m->len is uint16_t, so allocation size is capped at 64K. */
332 		m->buf = malloc(m->len, M_IIC, M_WAITOK);
333 		if (!(m->flags & IIC_M_RD))
334 			error = copyin(usrbufs[i], m->buf, m->len);
335 	}
336 
337 	if (error == 0)
338 		error = iicbus_request_bus(parent, iicdev,
339 		    (flags & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));
340 
341 	if (error == 0) {
342 		error = iicbus_transfer(iicdev, buf, d->nmsgs);
343 		iicbus_release_bus(parent, iicdev);
344 	}
345 
346 	/* Copyout all read segments, free up kernel buffers */
347 	for (i = 0; i < d->nmsgs; i++) {
348 		m = &(buf[i]);
349 		if ((error == 0) && (m->flags & IIC_M_RD))
350 			error = copyout(m->buf, usrbufs[i], m->len);
351 		free(m->buf, M_IIC);
352 	}
353 
354 	free(usrbufs, M_IIC);
355 	free(buf, M_IIC);
356 	return (error);
357 }
358 
359 static int
360 iicioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags, struct thread *td)
361 {
362 	device_t parent, iicdev;
363 	struct iiccmd *s;
364 	struct uio ubuf;
365 	struct iovec uvec;
366 	struct iic_cdevpriv *priv;
367 	int error;
368 
369 	s = (struct iiccmd *)data;
370 	error = devfs_get_cdevpriv((void**)&priv);
371 	if (error != 0)
372 		return (error);
373 
374 	KASSERT(priv != NULL, ("iic cdevpriv should not be NULL!"));
375 
376 	iicdev = priv->sc->sc_dev;
377 	parent = device_get_parent(iicdev);
378 	IIC_LOCK(priv);
379 
380 
381 	switch (cmd) {
382 	case I2CSTART:
383 		if (priv->started) {
384 			error = EINVAL;
385 			break;
386 		}
387 		error = iicbus_request_bus(parent, iicdev,
388 		    (flags & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));
389 
390 		if (error == 0)
391 			error = iicbus_start(parent, s->slave, 0);
392 
393 		if (error == 0) {
394 			priv->addr = s->slave;
395 			priv->started = true;
396 		} else
397 			iicbus_release_bus(parent, iicdev);
398 
399 		break;
400 
401 	case I2CSTOP:
402 		if (priv->started) {
403 			error = iicbus_stop(parent);
404 			iicbus_release_bus(parent, iicdev);
405 			priv->started = false;
406 		}
407 
408 		break;
409 
410 	case I2CRSTCARD:
411 		/*
412 		 * Bus should be owned before we reset it.
413 		 * We allow the bus to be already owned as the result of an in-progress
414 		 * sequence; however, bus reset will always be followed by release
415 		 * (a new start is presumably needed for I/O anyway). */
416 		if (!priv->started)
417 			error = iicbus_request_bus(parent, iicdev,
418 			    (flags & O_NONBLOCK) ? IIC_DONTWAIT : (IIC_WAIT | IIC_INTR));
419 
420 		if (error == 0) {
421 			error = iicbus_reset(parent, IIC_UNKNOWN, 0, NULL);
422 			/*
423 			 * Ignore IIC_ENOADDR as it only means we have a master-only
424 			 * controller.
425 			 */
426 			if (error == IIC_ENOADDR)
427 				error = 0;
428 
429 			iicbus_release_bus(parent, iicdev);
430 			priv->started = false;
431 		}
432 		break;
433 
434 	case I2CWRITE:
435 		if (!priv->started) {
436 			error = EINVAL;
437 			break;
438 		}
439 		uvec.iov_base = s->buf;
440 		uvec.iov_len = s->count;
441 		ubuf.uio_iov = &uvec;
442 		ubuf.uio_iovcnt = 1;
443 		ubuf.uio_segflg = UIO_USERSPACE;
444 		ubuf.uio_td = td;
445 		ubuf.uio_resid = s->count;
446 		ubuf.uio_offset = 0;
447 		ubuf.uio_rw = UIO_WRITE;
448 		error = iicuio_move(priv, &ubuf, 0);
449 		break;
450 
451 	case I2CREAD:
452 		if (!priv->started) {
453 			error = EINVAL;
454 			break;
455 		}
456 		uvec.iov_base = s->buf;
457 		uvec.iov_len = s->count;
458 		ubuf.uio_iov = &uvec;
459 		ubuf.uio_iovcnt = 1;
460 		ubuf.uio_segflg = UIO_USERSPACE;
461 		ubuf.uio_td = td;
462 		ubuf.uio_resid = s->count;
463 		ubuf.uio_offset = 0;
464 		ubuf.uio_rw = UIO_READ;
465 		error = iicuio_move(priv, &ubuf, s->last);
466 		break;
467 
468 	case I2CRDWR:
469 		/*
470 		 * The rdwr list should be a self-contained set of
471 		 * transactions.  Fail if another transaction is in progress.
472                  */
473 		if (priv->started) {
474 			error = EINVAL;
475 			break;
476 		}
477 
478 		error = iicrdwr(priv, (struct iic_rdwr_data *)data, flags);
479 
480 		break;
481 
482 	case I2CRPTSTART:
483 		if (!priv->started) {
484 			error = EINVAL;
485 			break;
486 		}
487 		error = iicbus_repeated_start(parent, s->slave, 0);
488 		break;
489 
490 	case I2CSADDR:
491 		priv->addr = *((uint8_t*)data);
492 		break;
493 
494 	default:
495 		error = ENOTTY;
496 	}
497 
498 	IIC_UNLOCK(priv);
499 	return (error);
500 }
501 
502 DRIVER_MODULE(iic, iicbus, iic_driver, iic_devclass, 0, 0);
503 MODULE_DEPEND(iic, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
504 MODULE_VERSION(iic, 1);
505