xref: /freebsd/sys/arm/nvidia/tegra_i2c.c (revision 7899f917b1c0ea178f1d2be0cfb452086d079d23)
1 /*-
2  * Copyright (c) 2016 Michal Meloun <mmel@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 /*
29  * I2C driver for Tegra SoCs.
30  */
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/bus.h>
34 #include <sys/kernel.h>
35 #include <sys/limits.h>
36 #include <sys/module.h>
37 #include <sys/resource.h>
38 
39 #include <machine/bus.h>
40 #include <machine/resource.h>
41 #include <sys/rman.h>
42 
43 #include <sys/lock.h>
44 #include <sys/mutex.h>
45 
46 #include <dev/clk/clk.h>
47 #include <dev/hwreset/hwreset.h>
48 #include <dev/iicbus/iiconf.h>
49 #include <dev/iicbus/iicbus.h>
50 #include <dev/ofw/ofw_bus.h>
51 #include <dev/ofw/ofw_bus_subr.h>
52 
53 #include "iicbus_if.h"
54 
55 #define	I2C_CNFG				0x000
56 #define	 I2C_CNFG_MSTR_CLR_BUS_ON_TIMEOUT		(1 << 15)
57 #define	 I2C_CNFG_DEBOUNCE_CNT(x)			(((x) & 0x07) << 12)
58 #define	 I2C_CNFG_NEW_MASTER_FSM			(1 << 11)
59 #define	 I2C_CNFG_PACKET_MODE_EN			(1 << 10)
60 #define	 I2C_CNFG_SEND					(1 <<  9)
61 #define	 I2C_CNFG_NOACK					(1 <<  8)
62 #define	 I2C_CNFG_CMD2					(1 <<  7)
63 #define	 I2C_CNFG_CMD1					(1 <<  6)
64 #define	 I2C_CNFG_START					(1 <<  5)
65 #define	 I2C_CNFG_SLV2					(1 <<  4)
66 #define	 I2C_CNFG_LENGTH_SHIFT				1
67 #define	 I2C_CNFG_LENGTH_MASK				0x7
68 #define	 I2C_CNFG_A_MOD					(1 <<  0)
69 
70 #define	I2C_CMD_ADDR0				0x004
71 #define	I2C_CMD_ADDR1				0x008
72 #define	I2C_CMD_DATA1				0x00c
73 #define	I2C_CMD_DATA2				0x010
74 #define	I2C_STATUS				0x01c
75 #define	I2C_SL_CNFG				0x020
76 #define	I2C_SL_RCVD				0x024
77 #define	I2C_SL_STATUS				0x028
78 #define	I2C_SL_ADDR1				0x02c
79 #define	I2C_SL_ADDR2				0x030
80 #define	I2C_TLOW_SEXT				0x034
81 #define	I2C_SL_DELAY_COUNT			0x03c
82 #define	I2C_SL_INT_MASK				0x040
83 #define	I2C_SL_INT_SOURCE			0x044
84 #define	I2C_SL_INT_SET				0x048
85 #define	I2C_TX_PACKET_FIFO			0x050
86 #define	I2C_RX_FIFO				0x054
87 #define	I2C_PACKET_TRANSFER_STATUS		0x058
88 #define	I2C_FIFO_CONTROL			0x05c
89 #define	 I2C_FIFO_CONTROL_SLV_TX_FIFO_TRIG(x)		(((x) & 0x07) << 13)
90 #define	 I2C_FIFO_CONTROL_SLV_RX_FIFO_TRIG(x)		(((x) & 0x07) << 10)
91 #define	 I2C_FIFO_CONTROL_SLV_TX_FIFO_FLUSH		(1 <<  9)
92 #define	 I2C_FIFO_CONTROL_SLV_RX_FIFO_FLUSH		(1 <<  8)
93 #define	 I2C_FIFO_CONTROL_TX_FIFO_TRIG(x)		(((x) & 0x07) << 5)
94 #define	 I2C_FIFO_CONTROL_RX_FIFO_TRIG(x)		(((x) & 0x07) << 2)
95 #define	 I2C_FIFO_CONTROL_TX_FIFO_FLUSH			(1 << 1)
96 #define	 I2C_FIFO_CONTROL_RX_FIFO_FLUSH			(1 << 0)
97 
98 #define	I2C_FIFO_STATUS				0x060
99 #define	 I2C_FIFO_STATUS_SLV_XFER_ERR_REASON		(1 << 25)
100 #define	 I2C_FIFO_STATUS_TX_FIFO_SLV_EMPTY_CNT(x)	(((x) >> 20) & 0xF)
101 #define	 I2C_FIFO_STATUS_RX_FIFO_SLV_FULL_CNT(x)	(((x) >> 16) & 0xF)
102 #define	 I2C_FIFO_STATUS_TX_FIFO_EMPTY_CNT(x)		(((x) >>  4) & 0xF)
103 #define	 I2C_FIFO_STATUS_RX_FIFO_FULL_CNT(x)		(((x) >>  0) & 0xF)
104 
105 #define	I2C_INTERRUPT_MASK_REGISTER		0x064
106 #define	I2C_INTERRUPT_STATUS_REGISTER		0x068
107 #define	 I2C_INT_SLV_ACK_WITHHELD			(1 << 28)
108 #define	 I2C_INT_SLV_RD2WR				(1 << 27)
109 #define	 I2C_INT_SLV_WR2RD				(1 << 26)
110 #define	 I2C_INT_SLV_PKT_XFER_ERR			(1 << 25)
111 #define	 I2C_INT_SLV_TX_BUFFER_REQ			(1 << 24)
112 #define	 I2C_INT_SLV_RX_BUFFER_FILLED			(1 << 23)
113 #define	 I2C_INT_SLV_PACKET_XFER_COMPLETE		(1 << 22)
114 #define	 I2C_INT_SLV_TFIFO_OVF				(1 << 21)
115 #define	 I2C_INT_SLV_RFIFO_UNF				(1 << 20)
116 #define	 I2C_INT_SLV_TFIFO_DATA_REQ			(1 << 17)
117 #define	 I2C_INT_SLV_RFIFO_DATA_REQ			(1 << 16)
118 #define	 I2C_INT_BUS_CLEAR_DONE				(1 << 11)
119 #define	 I2C_INT_TLOW_MEXT_TIMEOUT			(1 << 10)
120 #define	 I2C_INT_TLOW_SEXT_TIMEOUT			(1 <<  9)
121 #define	 I2C_INT_TIMEOUT				(1 <<  8)
122 #define	 I2C_INT_PACKET_XFER_COMPLETE			(1 <<  7)
123 #define	 I2C_INT_ALL_PACKETS_XFER_COMPLETE		(1 <<  6)
124 #define	 I2C_INT_TFIFO_OVR				(1 <<  5)
125 #define	 I2C_INT_RFIFO_UNF				(1 <<  4)
126 #define	 I2C_INT_NOACK					(1 <<  3)
127 #define	 I2C_INT_ARB_LOST				(1 <<  2)
128 #define	 I2C_INT_TFIFO_DATA_REQ				(1 <<  1)
129 #define	 I2C_INT_RFIFO_DATA_REQ				(1 <<  0)
130 #define	 I2C_ERROR_MASK		(I2C_INT_ARB_LOST | I2C_INT_NOACK |	 \
131 				I2C_INT_RFIFO_UNF | I2C_INT_TFIFO_OVR)
132 
133 #define	I2C_CLK_DIVISOR				0x06c
134 #define	 I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT		16
135 #define	 I2C_CLK_DIVISOR_STD_FAST_MODE_MASK		0xffff
136 #define	 I2C_CLK_DIVISOR_HSMODE_SHIFT			0
137 #define	 I2C_CLK_DIVISOR_HSMODE_MASK			0xffff
138 #define	I2C_INTERRUPT_SOURCE_REGISTER		0x070
139 #define	I2C_INTERRUPT_SET_REGISTER		0x074
140 #define	I2C_SLV_TX_PACKET_FIFO			0x07c
141 #define	I2C_SLV_PACKET_STATUS			0x080
142 #define	I2C_BUS_CLEAR_CONFIG			0x084
143 #define	 I2C_BUS_CLEAR_CONFIG_BC_SCLK_THRESHOLD(x)	(((x) & 0xFF) << 16)
144 #define	 I2C_BUS_CLEAR_CONFIG_BC_STOP_COND		(1 << 2)
145 #define	 I2C_BUS_CLEAR_CONFIG_BC_TERMINATE		(1 << 1)
146 #define	 I2C_BUS_CLEAR_CONFIG_BC_ENABLE			(1 << 0)
147 
148 #define	I2C_BUS_CLEAR_STATUS			0x088
149 #define	 I2C_BUS_CLEAR_STATUS_BC_STATUS			(1 << 0)
150 
151 #define	I2C_CONFIG_LOAD				0x08c
152 #define	 I2C_CONFIG_LOAD_TIMEOUT_CONFIG_LOAD		(1 << 2)
153 #define	 I2C_CONFIG_LOAD_SLV_CONFIG_LOAD		(1 << 1)
154 #define	 I2C_CONFIG_LOAD_MSTR_CONFIG_LOAD		(1 << 0)
155 
156 #define	I2C_INTERFACE_TIMING_0			0x094
157 #define	I2C_INTERFACE_TIMING_1			0x098
158 #define	I2C_HS_INTERFACE_TIMING_0		0x09c
159 #define	I2C_HS_INTERFACE_TIMING_1		0x0a0
160 
161 /* Protocol header 0 */
162 #define	PACKET_HEADER0_HEADER_SIZE_SHIFT	28
163 #define	PACKET_HEADER0_HEADER_SIZE_MASK		0x3
164 #define	PACKET_HEADER0_PACKET_ID_SHIFT		16
165 #define	PACKET_HEADER0_PACKET_ID_MASK		0xff
166 #define	PACKET_HEADER0_CONT_ID_SHIFT		12
167 #define	PACKET_HEADER0_CONT_ID_MASK		0xf
168 #define	PACKET_HEADER0_PROTOCOL_I2C		(1 << 4)
169 #define	PACKET_HEADER0_TYPE_SHIFT		0
170 #define	PACKET_HEADER0_TYPE_MASK		0x7
171 
172 /* I2C header */
173 #define	I2C_HEADER_HIGHSPEED_MODE		(1 << 22)
174 #define	I2C_HEADER_CONT_ON_NAK			(1 << 21)
175 #define	I2C_HEADER_SEND_START_BYTE		(1 << 20)
176 #define	I2C_HEADER_READ				(1 << 19)
177 #define	I2C_HEADER_10BIT_ADDR			(1 << 18)
178 #define	I2C_HEADER_IE_ENABLE			(1 << 17)
179 #define	I2C_HEADER_REPEAT_START			(1 << 16)
180 #define	I2C_HEADER_CONTINUE_XFER		(1 << 15)
181 #define	I2C_HEADER_MASTER_ADDR_SHIFT		12
182 #define	I2C_HEADER_MASTER_ADDR_MASK		0x7
183 #define	I2C_HEADER_SLAVE_ADDR_SHIFT		0
184 #define	I2C_HEADER_SLAVE_ADDR_MASK		0x3ff
185 
186 #define	I2C_CLK_DIVISOR_STD_FAST_MODE		0x19
187 #define	I2C_CLK_MULTIPLIER_STD_FAST_MODE	8
188 
189 #define	I2C_REQUEST_TIMEOUT			(5 * hz)
190 
191 #define	WR4(_sc, _r, _v)	bus_write_4((_sc)->mem_res, (_r), (_v))
192 #define	RD4(_sc, _r)		bus_read_4((_sc)->mem_res, (_r))
193 
194 #define	LOCK(_sc)		mtx_lock(&(_sc)->mtx)
195 #define	UNLOCK(_sc)		mtx_unlock(&(_sc)->mtx)
196 #define	SLEEP(_sc, timeout)						\
197 	mtx_sleep(sc, &sc->mtx, 0, "i2cbuswait", timeout);
198 #define	LOCK_INIT(_sc)							\
199 	mtx_init(&_sc->mtx, device_get_nameunit(_sc->dev), "tegra_i2c", MTX_DEF)
200 #define	LOCK_DESTROY(_sc)	mtx_destroy(&_sc->mtx)
201 #define	ASSERT_LOCKED(_sc)	mtx_assert(&_sc->mtx, MA_OWNED)
202 #define	ASSERT_UNLOCKED(_sc)	mtx_assert(&_sc->mtx, MA_NOTOWNED)
203 
204 static struct ofw_compat_data compat_data[] = {
205 	{"nvidia,tegra124-i2c",	1},
206 	{"nvidia,tegra210-i2c",	1},
207 	{NULL,			0}
208 };
209 enum tegra_i2c_xfer_type {
210 	XFER_STOP, 		/* Send stop condition after xfer */
211 	XFER_REPEAT_START,	/* Send repeated start after xfer */
212 	XFER_CONTINUE		/* Don't send nothing */
213 } ;
214 
215 struct tegra_i2c_softc {
216 	device_t		dev;
217 	struct mtx		mtx;
218 
219 	struct resource		*mem_res;
220 	struct resource		*irq_res;
221 	void			*irq_h;
222 
223 	device_t		iicbus;
224 	clk_t			clk;
225 	hwreset_t		reset;
226 	uint32_t		core_freq;
227 	uint32_t		bus_freq;
228 	int			bus_inuse;
229 
230 	struct iic_msg		*msg;
231 	int			msg_idx;
232 	uint32_t		bus_err;
233 	int			done;
234 };
235 
236 static int
237 tegra_i2c_flush_fifo(struct tegra_i2c_softc *sc)
238 {
239 	int timeout;
240 	uint32_t reg;
241 
242 	reg = RD4(sc, I2C_FIFO_CONTROL);
243 	reg |= I2C_FIFO_CONTROL_TX_FIFO_FLUSH | I2C_FIFO_CONTROL_RX_FIFO_FLUSH;
244 	WR4(sc, I2C_FIFO_CONTROL, reg);
245 
246 	timeout = 10;
247 	while (timeout > 0) {
248 		reg = RD4(sc, I2C_FIFO_CONTROL);
249 		reg &= I2C_FIFO_CONTROL_TX_FIFO_FLUSH |
250 		    I2C_FIFO_CONTROL_RX_FIFO_FLUSH;
251 		if (reg == 0)
252 			break;
253 		DELAY(10);
254 	}
255 	if (timeout <= 0) {
256 		device_printf(sc->dev, "FIFO flush timedout\n");
257 		return (ETIMEDOUT);
258 	}
259 	return (0);
260 }
261 
262 static void
263 tegra_i2c_setup_clk(struct tegra_i2c_softc *sc, int clk_freq)
264 {
265 	int div;
266 
267 	div = ((sc->core_freq  / clk_freq)  / 10) - 1;
268 	if ((sc->core_freq / (10 * (div + 1)))  > clk_freq)
269 		div++;
270 	if (div > 65535)
271 		div = 65535;
272 	WR4(sc, I2C_CLK_DIVISOR,
273 	    (1 << I2C_CLK_DIVISOR_HSMODE_SHIFT) |
274 	    (div << I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT));
275 }
276 
277 static void
278 tegra_i2c_bus_clear(struct tegra_i2c_softc *sc)
279 {
280 	int timeout;
281 	uint32_t reg, status;
282 
283 	WR4(sc, I2C_BUS_CLEAR_CONFIG,
284 	    I2C_BUS_CLEAR_CONFIG_BC_SCLK_THRESHOLD(18) |
285 	    I2C_BUS_CLEAR_CONFIG_BC_STOP_COND |
286 	    I2C_BUS_CLEAR_CONFIG_BC_TERMINATE);
287 
288 	WR4(sc, I2C_CONFIG_LOAD, I2C_CONFIG_LOAD_MSTR_CONFIG_LOAD);
289 	for (timeout = 1000; timeout > 0; timeout--) {
290 		if (RD4(sc, I2C_CONFIG_LOAD) == 0)
291 			break;
292 		DELAY(10);
293 	}
294 	if (timeout <= 0)
295 		device_printf(sc->dev, "config load timeouted\n");
296 	reg = RD4(sc, I2C_BUS_CLEAR_CONFIG);
297 	reg |= I2C_BUS_CLEAR_CONFIG_BC_ENABLE;
298 	WR4(sc, I2C_BUS_CLEAR_CONFIG,reg);
299 
300 	for (timeout = 1000; timeout > 0; timeout--) {
301 		if ((RD4(sc, I2C_BUS_CLEAR_CONFIG) &
302 		    I2C_BUS_CLEAR_CONFIG_BC_ENABLE) == 0)
303 			break;
304 		DELAY(10);
305 	}
306 	if (timeout <= 0)
307 		device_printf(sc->dev, "bus clear timeouted\n");
308 
309 	status = RD4(sc, I2C_BUS_CLEAR_STATUS);
310 	if ((status & I2C_BUS_CLEAR_STATUS_BC_STATUS) == 0)
311 		device_printf(sc->dev, "bus clear failed\n");
312 }
313 
314 static int
315 tegra_i2c_hw_init(struct tegra_i2c_softc *sc)
316 {
317 	int rv, timeout;
318 
319 	/* Reset the core. */
320 	rv = hwreset_assert(sc->reset);
321 	if (rv != 0) {
322 		device_printf(sc->dev, "Cannot assert reset\n");
323 		return (rv);
324 	}
325 	DELAY(10);
326 	rv = hwreset_deassert(sc->reset);
327 	if (rv != 0) {
328 		device_printf(sc->dev, "Cannot clear reset\n");
329 		return (rv);
330 	}
331 
332 	WR4(sc, I2C_INTERRUPT_MASK_REGISTER, 0);
333 	WR4(sc, I2C_INTERRUPT_STATUS_REGISTER, 0xFFFFFFFF);
334 	WR4(sc, I2C_CNFG, I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN |
335 	    I2C_CNFG_DEBOUNCE_CNT(2));
336 
337 	tegra_i2c_setup_clk(sc, sc->bus_freq);
338 
339 	WR4(sc, I2C_FIFO_CONTROL, I2C_FIFO_CONTROL_TX_FIFO_TRIG(7) |
340 	    I2C_FIFO_CONTROL_RX_FIFO_TRIG(0));
341 
342 	WR4(sc, I2C_CONFIG_LOAD, I2C_CONFIG_LOAD_MSTR_CONFIG_LOAD);
343 	for (timeout = 1000; timeout > 0; timeout--) {
344 		if (RD4(sc, I2C_CONFIG_LOAD) == 0)
345 			break;
346 		DELAY(10);
347 	}
348 	if (timeout <= 0)
349 		device_printf(sc->dev, "config load timeouted\n");
350 
351 	tegra_i2c_bus_clear(sc);
352 	return (0);
353 }
354 
355 static int
356 tegra_i2c_tx(struct tegra_i2c_softc *sc)
357 {
358 	uint32_t reg;
359 	int cnt, i;
360 
361 	if (sc->msg_idx >= sc->msg->len)
362 		panic("Invalid call to tegra_i2c_tx\n");
363 
364 	while(sc->msg_idx < sc->msg->len) {
365 		reg = RD4(sc, I2C_FIFO_STATUS);
366 		if (I2C_FIFO_STATUS_TX_FIFO_EMPTY_CNT(reg) == 0)
367 			break;
368 		cnt = min(4, sc->msg->len - sc->msg_idx);
369 		reg = 0;
370 		for (i = 0;  i < cnt; i++) {
371 			reg |=  sc->msg->buf[sc->msg_idx] << (i * 8);
372 			sc->msg_idx++;
373 		}
374 		WR4(sc, I2C_TX_PACKET_FIFO, reg);
375 	}
376 	if (sc->msg_idx >= sc->msg->len)
377 		return (0);
378 	return (sc->msg->len - sc->msg_idx - 1);
379 }
380 
381 static int
382 tegra_i2c_rx(struct tegra_i2c_softc *sc)
383 {
384 	uint32_t reg;
385 	int cnt, i;
386 
387 	if (sc->msg_idx >= sc->msg->len)
388 		panic("Invalid call to tegra_i2c_rx\n");
389 
390 	while(sc->msg_idx < sc->msg->len) {
391 		reg = RD4(sc, I2C_FIFO_STATUS);
392 		if (I2C_FIFO_STATUS_RX_FIFO_FULL_CNT(reg) == 0)
393 			break;
394 		cnt = min(4, sc->msg->len - sc->msg_idx);
395 		reg = RD4(sc, I2C_RX_FIFO);
396 		for (i = 0;  i < cnt; i++) {
397 			sc->msg->buf[sc->msg_idx] = (reg >> (i * 8)) & 0xFF;
398 			sc->msg_idx++;
399 		}
400 	}
401 
402 	if (sc->msg_idx >= sc->msg->len)
403 		return (0);
404 	return (sc->msg->len - sc->msg_idx - 1);
405 }
406 
407 static void
408 tegra_i2c_intr(void *arg)
409 {
410 	struct tegra_i2c_softc *sc;
411 	uint32_t status, reg;
412 	int rv;
413 
414 	sc = (struct tegra_i2c_softc *)arg;
415 
416 	LOCK(sc);
417 	status = RD4(sc, I2C_INTERRUPT_SOURCE_REGISTER);
418 	if (sc->msg == NULL) {
419 		/* Unexpected interrupt - disable FIFOs, clear reset. */
420 		reg = RD4(sc, I2C_INTERRUPT_MASK_REGISTER);
421 		reg &= ~I2C_INT_TFIFO_DATA_REQ;
422 		reg &= ~I2C_INT_RFIFO_DATA_REQ;
423 		WR4(sc, I2C_INTERRUPT_MASK_REGISTER, 0);
424 		WR4(sc, I2C_INTERRUPT_STATUS_REGISTER, status);
425 		UNLOCK(sc);
426 		return;
427 	}
428 
429 	if ((status & I2C_ERROR_MASK) != 0) {
430 		if (status & I2C_INT_NOACK)
431 			sc->bus_err = IIC_ENOACK;
432 		if (status & I2C_INT_ARB_LOST)
433 			sc->bus_err = IIC_EBUSERR;
434 		if ((status & I2C_INT_TFIFO_OVR) ||
435 		    (status & I2C_INT_RFIFO_UNF))
436 			sc->bus_err = IIC_EBUSERR;
437 		sc->done = 1;
438 	} else if ((status & I2C_INT_RFIFO_DATA_REQ) &&
439 	    (sc->msg != NULL) && (sc->msg->flags & IIC_M_RD)) {
440 		rv = tegra_i2c_rx(sc);
441 		if (rv == 0) {
442 			reg = RD4(sc, I2C_INTERRUPT_MASK_REGISTER);
443 			reg &= ~I2C_INT_RFIFO_DATA_REQ;
444 			WR4(sc, I2C_INTERRUPT_MASK_REGISTER, reg);
445 		}
446 	} else if ((status & I2C_INT_TFIFO_DATA_REQ) &&
447 	    (sc->msg != NULL) && !(sc->msg->flags & IIC_M_RD)) {
448 		rv = tegra_i2c_tx(sc);
449 		if (rv == 0) {
450 			reg = RD4(sc, I2C_INTERRUPT_MASK_REGISTER);
451 			reg &= ~I2C_INT_TFIFO_DATA_REQ;
452 			WR4(sc, I2C_INTERRUPT_MASK_REGISTER, reg);
453 		}
454 	} else if ((status & I2C_INT_RFIFO_DATA_REQ) ||
455 		    (status & I2C_INT_TFIFO_DATA_REQ)) {
456 		device_printf(sc->dev, "Unexpected data interrupt: 0x%08X\n",
457 		    status);
458 		reg = RD4(sc, I2C_INTERRUPT_MASK_REGISTER);
459 		reg &= ~I2C_INT_TFIFO_DATA_REQ;
460 		reg &= ~I2C_INT_RFIFO_DATA_REQ;
461 		WR4(sc, I2C_INTERRUPT_MASK_REGISTER, reg);
462 	}
463 	if (status & I2C_INT_PACKET_XFER_COMPLETE)
464 		sc->done = 1;
465 	WR4(sc, I2C_INTERRUPT_STATUS_REGISTER, status);
466 	if (sc->done) {
467 		WR4(sc, I2C_INTERRUPT_MASK_REGISTER, 0);
468 		wakeup(&(sc->done));
469 	}
470 	UNLOCK(sc);
471 }
472 
473 static void
474 tegra_i2c_start_msg(struct tegra_i2c_softc *sc, struct iic_msg *msg,
475     enum tegra_i2c_xfer_type xtype)
476 {
477 	uint32_t tmp, mask;
478 
479 	/* Packet header. */
480 	tmp =  (0 << PACKET_HEADER0_HEADER_SIZE_SHIFT) |
481 	   PACKET_HEADER0_PROTOCOL_I2C |
482 	   (1 << PACKET_HEADER0_CONT_ID_SHIFT) |
483 	   (1 << PACKET_HEADER0_PACKET_ID_SHIFT);
484 	WR4(sc, I2C_TX_PACKET_FIFO, tmp);
485 
486 	/* Packet size. */
487 	WR4(sc, I2C_TX_PACKET_FIFO, msg->len - 1);
488 
489 	/* I2C header. */
490 	tmp = I2C_HEADER_IE_ENABLE;
491 	if (xtype == XFER_CONTINUE)
492 		tmp |= I2C_HEADER_CONTINUE_XFER;
493 	else if (xtype == XFER_REPEAT_START)
494 		tmp |= I2C_HEADER_REPEAT_START;
495 	tmp |= msg->slave << I2C_HEADER_SLAVE_ADDR_SHIFT;
496 	if (msg->flags & IIC_M_RD) {
497 		tmp |= I2C_HEADER_READ;
498 		tmp |= 1 << I2C_HEADER_SLAVE_ADDR_SHIFT;
499 	} else
500 		tmp &= ~(1 << I2C_HEADER_SLAVE_ADDR_SHIFT);
501 
502 	WR4(sc, I2C_TX_PACKET_FIFO, tmp);
503 
504 	/* Interrupt mask. */
505 	mask = I2C_INT_NOACK | I2C_INT_ARB_LOST | I2C_INT_PACKET_XFER_COMPLETE;
506 	if (msg->flags & IIC_M_RD)
507 		mask |= I2C_INT_RFIFO_DATA_REQ;
508 	else
509 		mask |= I2C_INT_TFIFO_DATA_REQ;
510 	WR4(sc, I2C_INTERRUPT_MASK_REGISTER, mask);
511 }
512 
513 static int
514 tegra_i2c_poll(struct tegra_i2c_softc *sc)
515 {
516 	int timeout;
517 
518 	for(timeout = 10000; timeout > 0; timeout--)  {
519 		UNLOCK(sc);
520 		tegra_i2c_intr(sc);
521 		LOCK(sc);
522 		if (sc->done != 0)
523 			 break;
524 		DELAY(1);
525 	}
526 	if (timeout <= 0)
527 		return (ETIMEDOUT);
528 	return (0);
529 }
530 
531 static int
532 tegra_i2c_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
533 {
534 	int rv, i;
535 	struct tegra_i2c_softc *sc;
536 	enum tegra_i2c_xfer_type xtype;
537 
538 	sc = device_get_softc(dev);
539 	LOCK(sc);
540 
541 	/* Get the bus. */
542 	while (sc->bus_inuse == 1)
543 		SLEEP(sc,  0);
544 	sc->bus_inuse = 1;
545 
546 	rv = 0;
547 	for (i = 0; i < nmsgs; i++) {
548 		sc->msg = &msgs[i];
549 		sc->msg_idx = 0;
550 		sc->bus_err = 0;
551 		sc->done = 0;
552 		/* Check for valid parameters. */
553 		if (sc->msg == NULL || sc->msg->buf == NULL ||
554 		    sc->msg->len == 0) {
555 			rv = EINVAL;
556 			break;
557 		}
558 
559 		/* Get flags for next transfer. */
560 		if (i == (nmsgs - 1)) {
561 			if (msgs[i].flags & IIC_M_NOSTOP)
562 				xtype = XFER_CONTINUE;
563 			else
564 				xtype = XFER_STOP;
565 		} else {
566 			if (msgs[i + 1].flags & IIC_M_NOSTART)
567 				xtype = XFER_CONTINUE;
568 			else
569 				xtype = XFER_REPEAT_START;
570 		}
571 		tegra_i2c_start_msg(sc, sc->msg, xtype);
572 		if (cold)
573 			rv = tegra_i2c_poll(sc);
574 		else
575 			rv = msleep(&sc->done, &sc->mtx, PZERO, "iic",
576 			    I2C_REQUEST_TIMEOUT);
577 
578 		WR4(sc, I2C_INTERRUPT_MASK_REGISTER, 0);
579 		WR4(sc, I2C_INTERRUPT_STATUS_REGISTER, 0xFFFFFFFF);
580 		if (rv == 0)
581 			rv = sc->bus_err;
582 		if (rv != 0)
583 			break;
584 	}
585 
586 	if (rv != 0) {
587 		tegra_i2c_hw_init(sc);
588 		tegra_i2c_flush_fifo(sc);
589 	}
590 
591 	sc->msg = NULL;
592 	sc->msg_idx = 0;
593 	sc->bus_err = 0;
594 	sc->done = 0;
595 
596 	/* Wake up the processes that are waiting for the bus. */
597 	sc->bus_inuse = 0;
598 	wakeup(sc);
599 	UNLOCK(sc);
600 
601 	return (rv);
602 }
603 
604 static int
605 tegra_i2c_iicbus_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
606 {
607 	struct tegra_i2c_softc *sc;
608 	int busfreq;
609 
610 	sc = device_get_softc(dev);
611 	busfreq = IICBUS_GET_FREQUENCY(sc->iicbus, speed);
612 	sc = device_get_softc(dev);
613 	LOCK(sc);
614 	tegra_i2c_setup_clk(sc, busfreq);
615 	UNLOCK(sc);
616 	return (0);
617 }
618 
619 static int
620 tegra_i2c_probe(device_t dev)
621 {
622 	if (!ofw_bus_status_okay(dev))
623 		return (ENXIO);
624 
625 	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
626 		return (ENXIO);
627 
628 	return (BUS_PROBE_DEFAULT);
629 }
630 
631 static int
632 tegra_i2c_attach(device_t dev)
633 {
634 	int rv, rid;
635 	phandle_t node;
636 	struct tegra_i2c_softc *sc;
637 	uint64_t freq;
638 
639 	sc = device_get_softc(dev);
640 	sc->dev = dev;
641 	node = ofw_bus_get_node(dev);
642 
643 	LOCK_INIT(sc);
644 
645 	/* Get the memory resource for the register mapping. */
646 	rid = 0;
647 	sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
648 	    RF_ACTIVE);
649 	if (sc->mem_res == NULL) {
650 		device_printf(dev, "Cannot map registers.\n");
651 		rv = ENXIO;
652 		goto fail;
653 	}
654 
655 	/* Allocate our IRQ resource. */
656 	rid = 0;
657 	sc->irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
658 	    RF_ACTIVE);
659 	if (sc->irq_res == NULL) {
660 		device_printf(dev, "Cannot allocate interrupt.\n");
661 		rv = ENXIO;
662 		goto fail;
663 	}
664 
665 	/* FDT resources. */
666 	rv = clk_get_by_ofw_name(dev, 0, "div-clk", &sc->clk);
667 	if (rv != 0) {
668 		device_printf(dev, "Cannot get i2c clock: %d\n", rv);
669 		goto fail;
670 	}
671 	rv = hwreset_get_by_ofw_name(sc->dev, 0, "i2c", &sc->reset);
672 	if (rv != 0) {
673 		device_printf(sc->dev, "Cannot get i2c reset\n");
674 		return (ENXIO);
675 	}
676 	rv = OF_getencprop(node, "clock-frequency", &sc->bus_freq,
677 	    sizeof(sc->bus_freq));
678 	if (rv != sizeof(sc->bus_freq)) {
679 		sc->bus_freq = 100000;
680 	}
681 
682 	/* Request maximum frequency for I2C block 136MHz (408MHz / 3). */
683 	rv = clk_set_freq(sc->clk, 136000000, CLK_SET_ROUND_DOWN);
684 	if (rv != 0) {
685 		device_printf(dev, "Cannot set clock frequency\n");
686 		goto fail;
687 	}
688 	rv = clk_get_freq(sc->clk, &freq);
689 	if (rv != 0) {
690 		device_printf(dev, "Cannot get clock frequency\n");
691 		goto fail;
692 	}
693 	sc->core_freq = (uint32_t)freq;
694 
695 	rv = clk_enable(sc->clk);
696 	if (rv != 0) {
697 		device_printf(dev, "Cannot enable clock: %d\n", rv);
698 		goto fail;
699 	}
700 
701 	/* Init hardware. */
702 	rv = tegra_i2c_hw_init(sc);
703 	if (rv) {
704 		device_printf(dev, "tegra_i2c_activate failed\n");
705 		goto fail;
706 	}
707 
708 	/* Setup interrupt. */
709 	rv = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_MISC | INTR_MPSAFE,
710 	    NULL, tegra_i2c_intr, sc, &sc->irq_h);
711 	if (rv) {
712 		device_printf(dev, "Cannot setup interrupt.\n");
713 		goto fail;
714 	}
715 
716 	/* Attach the iicbus. */
717 	sc->iicbus = device_add_child(dev, "iicbus", DEVICE_UNIT_ANY);
718 	if (sc->iicbus == NULL) {
719 		device_printf(dev, "Could not allocate iicbus instance.\n");
720 		rv = ENXIO;
721 		goto fail;
722 	}
723 
724 	/* Probe and attach the iicbus. */
725 	return (bus_generic_attach(dev));
726 
727 fail:
728 	if (sc->irq_h != NULL)
729 		bus_teardown_intr(dev, sc->irq_res, sc->irq_h);
730 	if (sc->irq_res != NULL)
731 		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->irq_res);
732 	if (sc->mem_res != NULL)
733 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->mem_res);
734 	LOCK_DESTROY(sc);
735 
736 	return (rv);
737 }
738 
739 static int
740 tegra_i2c_detach(device_t dev)
741 {
742 	struct tegra_i2c_softc *sc;
743 
744 	sc = device_get_softc(dev);
745 	tegra_i2c_hw_init(sc);
746 	if (sc->irq_h != NULL)
747 		bus_teardown_intr(dev, sc->irq_res, sc->irq_h);
748 	if (sc->irq_res != NULL)
749 		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->irq_res);
750 	if (sc->mem_res != NULL)
751 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->mem_res);
752 
753 	LOCK_DESTROY(sc);
754 	if (sc->iicbus)
755 		device_delete_child(dev, sc->iicbus);
756 	return (bus_generic_detach(dev));
757 }
758 
759 static phandle_t
760 tegra_i2c_get_node(device_t bus, device_t dev)
761 {
762 
763 	/* Share controller node with iibus device. */
764 	return (ofw_bus_get_node(bus));
765 }
766 
767 static device_method_t tegra_i2c_methods[] = {
768 	/* Device interface */
769 	DEVMETHOD(device_probe,		tegra_i2c_probe),
770 	DEVMETHOD(device_attach,	tegra_i2c_attach),
771 	DEVMETHOD(device_detach,	tegra_i2c_detach),
772 
773 	/* Bus interface */
774 	DEVMETHOD(bus_setup_intr,	bus_generic_setup_intr),
775 	DEVMETHOD(bus_teardown_intr,	bus_generic_teardown_intr),
776 	DEVMETHOD(bus_alloc_resource,	bus_generic_alloc_resource),
777 	DEVMETHOD(bus_release_resource,	bus_generic_release_resource),
778 	DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
779 	DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
780 	DEVMETHOD(bus_adjust_resource,	bus_generic_adjust_resource),
781 	DEVMETHOD(bus_set_resource,	bus_generic_rl_set_resource),
782 	DEVMETHOD(bus_get_resource,	bus_generic_rl_get_resource),
783 
784 	/* OFW methods */
785 	DEVMETHOD(ofw_bus_get_node,	tegra_i2c_get_node),
786 
787 	/* iicbus interface */
788 	DEVMETHOD(iicbus_callback,	iicbus_null_callback),
789 	DEVMETHOD(iicbus_reset,		tegra_i2c_iicbus_reset),
790 	DEVMETHOD(iicbus_transfer,	tegra_i2c_transfer),
791 
792 	DEVMETHOD_END
793 };
794 
795 static DEFINE_CLASS_0(iichb, tegra_i2c_driver, tegra_i2c_methods,
796     sizeof(struct tegra_i2c_softc));
797 EARLY_DRIVER_MODULE(tegra_iic, simplebus, tegra_i2c_driver, NULL, NULL, 73);
798