xref: /openbsd/sys/arch/armv7/omap/ti_iic.c (revision b8746ecc)
1 /*	$OpenBSD: ti_iic.c,v 1.5 2016/06/26 07:25:05 jsg Exp $	*/
2 /* $NetBSD: ti_iic.c,v 1.4 2013/04/25 13:04:27 rkujawa Exp $ */
3 
4 /*
5  * Copyright (c) 2013 Manuel Bouyer.  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 ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 /*-
29  * Copyright (c) 2012 Jared D. McNeill <jmcneill@invisible.ca>
30  * All rights reserved.
31  *
32  * Redistribution and use in source and binary forms, with or without
33  * modification, are permitted provided that the following conditions
34  * are met:
35  * 1. Redistributions of source code must retain the above copyright
36  *    notice, this list of conditions and the following disclaimer.
37  * 2. The name of the author may not be used to endorse or promote products
38  *    derived from this software without specific prior written permission.
39  *
40  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
41  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
42  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
43  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
44  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
45  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
47  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  */
52 
53 #include <sys/cdefs.h>
54 #include <sys/param.h>
55 #include <sys/systm.h>
56 #include <sys/device.h>
57 #include <sys/kernel.h>
58 #include <sys/rwlock.h>
59 
60 #include <machine/bus.h>
61 #include <machine/intr.h>
62 #include <machine/fdt.h>
63 
64 #include <dev/i2c/i2cvar.h>
65 
66 #include <armv7/armv7/armv7var.h>
67 #include <armv7/omap/prcmvar.h>
68 #include <armv7/omap/sitara_cm.h>
69 #include <armv7/omap/sitara_cmreg.h>
70 #include <armv7/omap/ti_iicreg.h>
71 
72 #include <dev/ofw/openfirm.h>
73 
74 #ifndef AM335X_I2C_SLAVE_ADDR
75 #define AM335X_I2C_SLAVE_ADDR	0x01
76 #endif
77 
78 #ifdef I2CDEBUG
79 #define DPRINTF(args)	printf args
80 #else
81 #define DPRINTF(args)
82 #endif
83 
84 /* operation in progress */
85 typedef enum {
86 	TI_I2CREAD,
87 	TI_I2CWRITE,
88 	TI_I2CDONE,
89 	TI_I2CERROR
90 } ti_i2cop_t;
91 
92 struct ti_iic_softc {
93 	struct device		sc_dev;
94 	struct i2c_controller	sc_ic;
95 	struct rwlock		sc_buslock;
96 	struct device		*sc_i2cdev;
97 
98 	bus_space_tag_t		sc_iot;
99 	bus_space_handle_t	sc_ioh;
100 
101 	void			*sc_ih;
102 	int			sc_node;
103 	ti_i2cop_t		sc_op;
104 	int			sc_buflen;
105 	int			sc_bufidx;
106 	char			*sc_buf;
107 
108 	int			sc_rxthres;
109 	int			sc_txthres;
110 };
111 
112 
113 #define I2C_READ_REG(sc, reg)		\
114 	bus_space_read_2((sc)->sc_iot, (sc)->sc_ioh, (reg))
115 #define I2C_READ_DATA(sc)		\
116 	bus_space_read_1((sc)->sc_iot, (sc)->sc_ioh, AM335X_I2C_DATA);
117 #define I2C_WRITE_REG(sc, reg, val)	\
118 	bus_space_write_2((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
119 #define I2C_WRITE_DATA(sc, val)		\
120 	bus_space_write_1((sc)->sc_iot, (sc)->sc_ioh, AM335X_I2C_DATA, (val))
121 
122 #define DEVNAME(sc)	((sc)->sc_dev.dv_xname)
123 
124 int	ti_iic_match(struct device *, void *, void *);
125 void	ti_iic_attach(struct device *, struct device *, void *);
126 int	ti_iic_intr(void *);
127 
128 int	ti_iic_acquire_bus(void *, int);
129 void	ti_iic_release_bus(void *, int);
130 int	ti_iic_exec(void *, i2c_op_t, i2c_addr_t, const void *, size_t, void *,
131 	    size_t, int);
132 void	ti_iic_scan(struct device *, struct i2cbus_attach_args *, void *);
133 
134 int	ti_iic_reset(struct ti_iic_softc *);
135 int	ti_iic_op(struct ti_iic_softc *, i2c_addr_t, ti_i2cop_t, uint8_t *,
136 	    size_t, int);
137 void	ti_iic_handle_intr(struct ti_iic_softc *, uint32_t);
138 void	ti_iic_do_read(struct ti_iic_softc *, uint32_t);
139 void	ti_iic_do_write(struct ti_iic_softc *, uint32_t);
140 
141 int	ti_iic_wait(struct ti_iic_softc *, uint16_t, uint16_t, int);
142 uint32_t	ti_iic_stat(struct ti_iic_softc *, uint32_t);
143 int	ti_iic_flush(struct ti_iic_softc *);
144 
145 struct cfattach tiiic_ca = {
146 	sizeof (struct ti_iic_softc), ti_iic_match, ti_iic_attach
147 };
148 
149 struct cfdriver tiiic_cd = {
150 	NULL, "tiiic", DV_DULL
151 };
152 
153 int
154 ti_iic_match(struct device *parent, void *match, void *aux)
155 {
156 	struct fdt_attach_args *faa = aux;
157 
158 	return OF_is_compatible(faa->fa_node, "ti,omap4-i2c");
159 }
160 
161 void
162 ti_iic_attach(struct device *parent, struct device *self, void *aux)
163 {
164 	struct ti_iic_softc *sc = (struct ti_iic_softc *)self;
165 	struct fdt_attach_args *faa = aux;
166 	struct i2cbus_attach_args iba;
167 	uint16_t rev;
168 	const char *mode;
169 	u_int state;
170 	int irq, unit, len;
171 	char buf[20];
172 	char hwmods[128];
173 	char *pin;
174 	/* BBB specific pin names */
175 	char *pins[6] = {"I2C0_SDA", "I2C0_SCL",
176 			"SPIO_D1", "SPI0_CS0",
177 			"UART1_CTSn", "UART1_RTSn"};
178 
179 	if (faa->fa_nreg != 2 || (faa->fa_nintr != 1 && faa->fa_nintr != 3))
180 		return;
181 
182 	sc->sc_iot = faa->fa_iot;
183 	sc->sc_node = faa->fa_node;
184 
185 	if (faa->fa_nintr == 1)
186 		irq = faa->fa_intr[0];
187 	else
188 		irq = faa->fa_intr[1];
189 
190 	unit = 0;
191 	if ((len = OF_getprop(faa->fa_node, "ti,hwmods", hwmods,
192 	    sizeof(hwmods))) == 5) {
193 		if (!strncmp(hwmods, "i2c", 3) &&
194 		    (hwmods[3] > '0') && (hwmods[3] <= '9'))
195 			unit = hwmods[3] - '1';
196 	}
197 
198 	rw_init(&sc->sc_buslock, "tiiilk");
199 
200 	sc->sc_rxthres = sc->sc_txthres = 4;
201 
202 	if (bus_space_map(sc->sc_iot, faa->fa_reg[0],
203 	    faa->fa_reg[1], 0, &sc->sc_ioh))
204 		panic("%s: bus_space_map failed!", DEVNAME(sc));
205 
206 	sc->sc_ih = arm_intr_establish(irq, IPL_NET,
207 	    ti_iic_intr, sc, DEVNAME(sc));
208 
209 	prcm_enablemodule(PRCM_I2C0 + unit);
210 
211 	if (board_id == BOARD_ID_AM335X_BEAGLEBONE) {
212 		pin = pins[unit * 2];
213 		snprintf(buf, sizeof buf, "I2C%d_SDA", unit);
214 		if (sitara_cm_padconf_set(pin, buf,
215 		    (0x01 << 4) | (0x01 << 5) | (0x01 << 6)) != 0) {
216 			printf(": can't switch %s pad\n", buf);
217 			return;
218 		}
219 		if (sitara_cm_padconf_get(pin, &mode, &state) == 0) {
220 			printf(": %s state %d ", mode, state);
221 		}
222 
223 		pin = pins[unit * 2 + 1];
224 		snprintf(buf, sizeof buf, "I2C%d_SCL", unit);
225 		if (sitara_cm_padconf_set(pin, buf,
226 		    (0x01 << 4) | (0x01 << 5) | (0x01 << 6)) != 0) {
227 			printf(": can't switch %s pad\n", buf);
228 			return;
229 		}
230 		if (sitara_cm_padconf_get(pin, &mode, &state) == 0) {
231 			printf(": %s state %d ", mode, state);
232 		}
233 	}
234 
235 	rev = I2C_READ_REG(sc, AM335X_I2C_REVNB_LO);
236 	printf(" rev %d.%d\n",
237 	    (int)I2C_REVNB_LO_MAJOR(rev),
238 	    (int)I2C_REVNB_LO_MINOR(rev));
239 
240 	ti_iic_reset(sc);
241 	ti_iic_flush(sc);
242 
243 	sc->sc_ic.ic_cookie = sc;
244 	sc->sc_ic.ic_acquire_bus = ti_iic_acquire_bus;
245 	sc->sc_ic.ic_release_bus = ti_iic_release_bus;
246 	sc->sc_ic.ic_exec = ti_iic_exec;
247 
248 	bzero(&iba, sizeof iba);
249 	iba.iba_name = "iic";
250 	iba.iba_tag = &sc->sc_ic;
251 	iba.iba_bus_scan = ti_iic_scan;
252 	iba.iba_bus_scan_arg = &sc->sc_node;
253 	(void) config_found(&sc->sc_dev, &iba, iicbus_print);
254 }
255 
256 int
257 ti_iic_intr(void *arg)
258 {
259 	struct ti_iic_softc *sc = arg;
260 	uint32_t stat;
261 
262 	DPRINTF(("ti_iic_intr\n"));
263 	stat = I2C_READ_REG(sc, AM335X_I2C_IRQSTATUS);
264 	I2C_WRITE_REG(sc, AM335X_I2C_IRQSTATUS, stat);
265 	DPRINTF(("ti_iic_intr pre handle sc->sc_op eq %#x\n", sc->sc_op));
266 
267 	ti_iic_handle_intr(sc, stat);
268 
269 	if (sc->sc_op == TI_I2CERROR || sc->sc_op == TI_I2CDONE) {
270 		DPRINTF(("ti_iic_intr post handle sc->sc_op %#x\n", sc->sc_op));
271 		wakeup(&sc->sc_dev);
272 	}
273 
274 	DPRINTF(("ti_iic_intr status 0x%x\n", stat));
275 
276 	return 1;
277 }
278 
279 int
280 ti_iic_acquire_bus(void *opaque, int flags)
281 {
282 	struct ti_iic_softc *sc = opaque;
283 
284 	if (flags & I2C_F_POLL)
285 		return 0;
286 
287 	return (rw_enter(&sc->sc_buslock, RW_WRITE));
288 }
289 
290 void
291 ti_iic_release_bus(void *opaque, int flags)
292 {
293 	struct ti_iic_softc *sc = opaque;
294 
295 	if (flags & I2C_F_POLL)
296 		return;
297 
298 	rw_exit(&sc->sc_buslock);
299 }
300 
301 int
302 ti_iic_exec(void *opaque, i2c_op_t op, i2c_addr_t addr,
303     const void *cmdbuf, size_t cmdlen, void *buf, size_t len, int flags)
304 {
305 	struct ti_iic_softc *sc = opaque;
306 	int err;
307 
308 
309 	DPRINTF(("ti_iic_exec: op 0x%x cmdlen %zd len %zd flags 0x%x\n",
310 	    op, cmdlen, len, flags));
311 
312 #define __UNCONST(a)  ((void *)(unsigned long)(const void *)(a))
313 	if (cmdlen > 0) {
314 		err = ti_iic_op(sc, addr, TI_I2CWRITE, __UNCONST(cmdbuf),
315 		    cmdlen, (I2C_OP_READ_P(op) ? 0 : I2C_F_STOP) | flags);
316 		if (err)
317 			goto done;
318 	}
319 	if (I2C_OP_STOP_P(op))
320 		flags |= I2C_F_STOP;
321 
322 	/*
323 	 * I2C controller doesn't allow for zero-byte transfers.
324 	 */
325 	if (len == 0)
326 		goto done;
327 
328 	if (I2C_OP_READ_P(op))
329 		err = ti_iic_op(sc, addr, TI_I2CREAD, buf, len, flags);
330 	else
331 		err = ti_iic_op(sc, addr, TI_I2CWRITE, buf, len, flags);
332 
333 done:
334 	if (err)
335 		ti_iic_reset(sc);
336 
337 	ti_iic_flush(sc);
338 
339 	DPRINTF(("ti_iic_exec: done %d\n", err));
340 	return err;
341 }
342 
343 int
344 ti_iic_reset(struct ti_iic_softc *sc)
345 {
346 	uint32_t psc, scll, sclh;
347 	int i;
348 
349 	DPRINTF(("ti_iic_reset\n"));
350 
351 	/* Disable */
352 	I2C_WRITE_REG(sc, AM335X_I2C_CON, 0);
353 	/* Soft reset */
354 	I2C_WRITE_REG(sc, AM335X_I2C_SYSC, I2C_SYSC_SRST);
355 	delay(1000);
356 	/* enable so that we can check for reset complete */
357 	I2C_WRITE_REG(sc, AM335X_I2C_CON, I2C_CON_EN);
358 	delay(1000);
359 	for (i = 0; i < 1000; i++) { /* 1s delay for reset */
360 		if (I2C_READ_REG(sc, AM335X_I2C_SYSS) & I2C_SYSS_RDONE)
361 			break;
362 	}
363 	/* Disable again */
364 	I2C_WRITE_REG(sc, AM335X_I2C_CON, 0);
365 	delay(50000);
366 
367 	if (i >= 1000) {
368 		printf("%s: couldn't reset module\n", DEVNAME(sc));
369 		return 1;
370 	}
371 
372 	/* XXX standard speed only */
373 	psc = 3;
374 	scll = 53;
375 	sclh = 55;
376 
377 	/* Clocks */
378 	I2C_WRITE_REG(sc, AM335X_I2C_PSC, psc);
379 	I2C_WRITE_REG(sc, AM335X_I2C_SCLL, scll);
380 	I2C_WRITE_REG(sc, AM335X_I2C_SCLH, sclh);
381 
382 	/* Own I2C address */
383 	I2C_WRITE_REG(sc, AM335X_I2C_OA, AM335X_I2C_SLAVE_ADDR);
384 
385 	/* 5 bytes fifo */
386 	I2C_WRITE_REG(sc, AM335X_I2C_BUF,
387 	    I2C_BUF_RXTRSH(sc->sc_rxthres) | I2C_BUF_TXTRSH(sc->sc_txthres));
388 
389 	/* Enable */
390 	I2C_WRITE_REG(sc, AM335X_I2C_CON, I2C_CON_EN);
391 
392 	return 0;
393 }
394 
395 int
396 ti_iic_op(struct ti_iic_softc *sc, i2c_addr_t addr, ti_i2cop_t op,
397     uint8_t *buf, size_t buflen, int flags)
398 {
399 	uint16_t con, stat, mask;
400 	int err, retry;
401 
402 	KASSERT(op == TI_I2CREAD || op == TI_I2CWRITE);
403 	DPRINTF(("ti_iic_op: addr %#x op %#x buf %p buflen %#x flags %#x\n",
404 	    addr, op, buf, (unsigned int) buflen, flags));
405 
406 	mask = I2C_IRQSTATUS_ARDY | I2C_IRQSTATUS_NACK | I2C_IRQSTATUS_AL;
407 	if (op == TI_I2CREAD)
408 		mask |= I2C_IRQSTATUS_RDR | I2C_IRQSTATUS_RRDY;
409 	else
410 		mask |= I2C_IRQSTATUS_XDR | I2C_IRQSTATUS_XRDY;
411 
412 	err = ti_iic_wait(sc, I2C_IRQSTATUS_BB, 0, flags);
413 	if (err) {
414 		DPRINTF(("ti_iic_op: wait error %d\n", err));
415 		return err;
416 	}
417 
418 	con = I2C_CON_EN;
419 	con |= I2C_CON_MST;
420 	con |= I2C_CON_STT;
421 	if (flags & I2C_F_STOP)
422 		con |= I2C_CON_STP;
423 	if (addr & ~0x7f)
424 		con |= I2C_CON_XSA;
425 	if (op == TI_I2CWRITE)
426 		con |= I2C_CON_TRX;
427 
428 	sc->sc_op = op;
429 	sc->sc_buf = buf;
430 	sc->sc_buflen = buflen;
431 	sc->sc_bufidx = 0;
432 
433 	I2C_WRITE_REG(sc,
434 	    AM335X_I2C_CON, I2C_CON_EN | I2C_CON_MST | I2C_CON_STP);
435 	DPRINTF(("ti_iic_op: op %d con 0x%x ", op, con));
436 	I2C_WRITE_REG(sc, AM335X_I2C_CNT, buflen);
437 	I2C_WRITE_REG(sc, AM335X_I2C_SA, (addr & I2C_SA_MASK));
438 	DPRINTF(("SA 0x%x len %d\n",
439 	    I2C_READ_REG(sc, AM335X_I2C_SA), I2C_READ_REG(sc, AM335X_I2C_CNT)));
440 
441 	if ((flags & I2C_F_POLL) == 0) {
442 		/* clear any pending interrupt */
443 		I2C_WRITE_REG(sc, AM335X_I2C_IRQSTATUS,
444 		    I2C_READ_REG(sc, AM335X_I2C_IRQSTATUS));
445 		/* and enable */
446 		I2C_WRITE_REG(sc, AM335X_I2C_IRQENABLE_SET, mask);
447 	}
448 	/* start transfer */
449 	I2C_WRITE_REG(sc, AM335X_I2C_CON, con);
450 
451 	if ((flags & I2C_F_POLL) == 0) {
452 		/* and wait for completion */
453 		DPRINTF(("ti_iic_op waiting, op %#x\n", sc->sc_op));
454 		while (sc->sc_op == op) {
455 			if (tsleep(&sc->sc_dev, PWAIT, "tiiic", 500)
456 			    == EWOULDBLOCK) {
457 				/* timeout */
458 				op = TI_I2CERROR;
459 			}
460 		}
461 		DPRINTF(("ti_iic_op waiting done, op %#x\n", sc->sc_op));
462 
463 		/* disable interrupts */
464 		I2C_WRITE_REG(sc, AM335X_I2C_IRQENABLE_CLR, 0xffff);
465 	} else {
466 		/* poll for completion */
467 		DPRINTF(("ti_iic_op polling, op %x\n", sc->sc_op));
468 		while (sc->sc_op == op) {
469 			stat = ti_iic_stat(sc, mask);
470 			DPRINTF(("ti_iic_op stat 0x%x\n", stat));
471 			if (stat == 0) /* timeout */
472 				sc->sc_op = TI_I2CERROR;
473 			else
474 				ti_iic_handle_intr(sc, stat);
475 			I2C_WRITE_REG(sc, AM335X_I2C_IRQSTATUS, stat);
476 		}
477 		DPRINTF(("ti_iic_op polling done, op now %x\n", sc->sc_op));
478 	}
479 	retry = 10000;
480 	I2C_WRITE_REG(sc, AM335X_I2C_CON, 0);
481 	while (I2C_READ_REG(sc, AM335X_I2C_CON) & I2C_CON_MST) {
482 		delay(100);
483 		if (--retry == 0)
484 			break;
485 	}
486 
487 	return (sc->sc_op == TI_I2CDONE) ? 0 : EIO;
488 }
489 
490 void
491 ti_iic_handle_intr(struct ti_iic_softc *sc, uint32_t stat)
492 {
493 	KASSERT(stat != 0);
494 	DPRINTF(("ti_iic_handle_intr stat %#x\n", stat));
495 
496 	if (stat & (I2C_IRQSTATUS_NACK|I2C_IRQSTATUS_AL)) {
497 		sc->sc_op = TI_I2CERROR;
498 		return;
499 	}
500 	if (stat & I2C_IRQSTATUS_ARDY) {
501 		sc->sc_op = TI_I2CDONE;
502 		return;
503 	}
504 	if (sc->sc_op == TI_I2CREAD)
505 		ti_iic_do_read(sc, stat);
506 	else if (sc->sc_op == TI_I2CWRITE)
507 		ti_iic_do_write(sc, stat);
508 	else
509 		return;
510 }
511 void
512 ti_iic_do_read(struct ti_iic_softc *sc, uint32_t stat)
513 {
514 	int len = 0;
515 
516 	DPRINTF(("ti_iic_do_read stat %#x\n", stat));
517 	if (stat & I2C_IRQSTATUS_RDR) {
518 		len = I2C_READ_REG(sc, AM335X_I2C_BUFSTAT);
519 		len = I2C_BUFSTAT_RXSTAT(len);
520 		DPRINTF(("ti_iic_do_read receive drain len %d left %d\n",
521 		    len, I2C_READ_REG(sc, AM335X_I2C_CNT)));
522 	} else if (stat & I2C_IRQSTATUS_RRDY) {
523 		len = sc->sc_rxthres + 1;
524 		DPRINTF(("ti_iic_do_read receive len %d left %d\n",
525 		    len, I2C_READ_REG(sc, AM335X_I2C_CNT)));
526 	}
527 	for (;
528 	    sc->sc_bufidx < sc->sc_buflen && len > 0;
529 	    sc->sc_bufidx++, len--) {
530 		sc->sc_buf[sc->sc_bufidx] = I2C_READ_DATA(sc);
531 		DPRINTF(("ti_iic_do_read got b[%d]=0x%x\n", sc->sc_bufidx,
532 		    sc->sc_buf[sc->sc_bufidx]));
533 	}
534 	DPRINTF(("ti_iic_do_read done\n"));
535 }
536 
537 void
538 ti_iic_do_write(struct ti_iic_softc *sc, uint32_t stat)
539 {
540 	int len = 0;
541 
542 	DPRINTF(("ti_iic_do_write stat %#x\n", stat));
543 
544 	if (stat & I2C_IRQSTATUS_XDR) {
545 		len = I2C_READ_REG(sc, AM335X_I2C_BUFSTAT);
546 		len = I2C_BUFSTAT_TXSTAT(len);
547 		DPRINTF(("ti_iic_do_write xmit drain len %d left %d\n",
548 		    len, I2C_READ_REG(sc, AM335X_I2C_CNT)));
549 	} else if (stat & I2C_IRQSTATUS_XRDY) {
550 		len = sc->sc_txthres + 1;
551 		DPRINTF(("ti_iic_do_write xmit len %d left %d\n",
552 		    len, I2C_READ_REG(sc, AM335X_I2C_CNT)));
553 	}
554 	for (;
555 	    sc->sc_bufidx < sc->sc_buflen && len > 0;
556 	    sc->sc_bufidx++, len--) {
557 		DPRINTF(("ti_iic_do_write send b[%d]=0x%x\n",
558 		    sc->sc_bufidx, sc->sc_buf[sc->sc_bufidx]));
559 		I2C_WRITE_DATA(sc, sc->sc_buf[sc->sc_bufidx]);
560 	}
561 	DPRINTF(("ti_iic_do_write done\n"));
562 }
563 
564 int
565 ti_iic_wait(struct ti_iic_softc *sc, uint16_t mask, uint16_t val, int flags)
566 {
567 	int retry = 10;
568 	uint16_t v;
569 	DPRINTF(("ti_iic_wait mask %#x val %#x flags %#x\n", mask, val, flags));
570 
571 	while (((v = I2C_READ_REG(sc, AM335X_I2C_IRQSTATUS_RAW)) & mask) != val) {
572 		--retry;
573 		if (retry == 0) {
574 			printf("%s: wait timeout, mask=%#x val=%#x stat=%#x\n",
575 			    DEVNAME(sc), mask, val, v);
576 			return EBUSY;
577 		}
578 		if (flags & I2C_F_POLL)
579 			delay(50000);
580 		else
581 			tsleep(&sc->sc_dev, PWAIT, "tiiic", 50);
582 	}
583 	DPRINTF(("ti_iic_wait done retry %#x\n", retry));
584 
585 	return 0;
586 }
587 
588 uint32_t
589 ti_iic_stat(struct ti_iic_softc *sc, uint32_t mask)
590 {
591 	uint32_t v;
592 	int retry = 500;
593 	DPRINTF(("ti_iic_wait mask %#x\n", mask));
594 	while (--retry > 0) {
595 		v = I2C_READ_REG(sc, AM335X_I2C_IRQSTATUS_RAW) & mask;
596 		if (v != 0)
597 			break;
598 		delay(100);
599 	}
600 	DPRINTF(("ti_iic_wait done retry %#x\n", retry));
601 	return v;
602 }
603 
604 int
605 ti_iic_flush(struct ti_iic_softc *sc)
606 {
607 	DPRINTF(("ti_iic_flush\n"));
608 #if 0
609 	int retry = 1000;
610 	uint16_t v;
611 
612 	while ((v =
613 	    I2C_READ_REG(sc, AM335X_I2C_IRQSTATUS_RAW)) & I2C_IRQSTATUS_RRDY) {
614 		if (--retry == 0) {
615 			printf("%s: flush timeout, stat = %#x\n", DEVNAME(sc), v);
616 			return EBUSY;
617 		}
618 		(void)I2C_READ_DATA(sc);
619 		delay(1000);
620 	}
621 #endif
622 
623 	I2C_WRITE_REG(sc, AM335X_I2C_CNT, 0);
624 	return 0;
625 }
626 
627 void
628 ti_iic_scan(struct device *self, struct i2cbus_attach_args *iba, void *aux)
629 {
630 	int iba_node = *(int *)aux;
631 	extern int iic_print(void *, const char *);
632 	struct i2c_attach_args ia;
633 	char name[32];
634 	uint32_t reg[1];
635 	int node;
636 
637 	for (node = OF_child(iba_node); node; node = OF_peer(node)) {
638 		memset(name, 0, sizeof(name));
639 		memset(reg, 0, sizeof(reg));
640 
641 		if (OF_getprop(node, "compatible", name, sizeof(name)) == -1)
642 			continue;
643 		if (name[0] == '\0')
644 			continue;
645 
646 		if (OF_getprop(node, "reg", &reg, sizeof(reg)) != sizeof(reg))
647 			continue;
648 
649 		memset(&ia, 0, sizeof(ia));
650 		ia.ia_tag = iba->iba_tag;
651 		ia.ia_addr = bemtoh32(&reg[0]);
652 		ia.ia_name = name;
653 		ia.ia_cookie = &node;
654 
655 		config_found(self, &ia, iic_print);
656 	}
657 }
658