xref: /freebsd/sys/arm/ti/ti_spi.c (revision 8ef24a0d4b28fe230e20637f56869cc4148cd2ca)
1 /*-
2  * Copyright (c) 2016 Rubicon Communications, LLC (Netgate)
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 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/bus.h>
33 
34 #include <sys/kernel.h>
35 #include <sys/module.h>
36 #include <sys/rman.h>
37 #include <sys/lock.h>
38 #include <sys/mutex.h>
39 #include <sys/sysctl.h>
40 
41 #include <machine/bus.h>
42 #include <machine/resource.h>
43 #include <machine/intr.h>
44 
45 #include <dev/fdt/fdt_common.h>
46 #include <dev/ofw/ofw_bus.h>
47 #include <dev/ofw/ofw_bus_subr.h>
48 
49 #include <dev/spibus/spi.h>
50 #include <dev/spibus/spibusvar.h>
51 
52 #include <arm/ti/ti_prcm.h>
53 #include <arm/ti/ti_hwmods.h>
54 #include <arm/ti/ti_spireg.h>
55 #include <arm/ti/ti_spivar.h>
56 
57 #include "spibus_if.h"
58 
59 static void ti_spi_intr(void *);
60 static int ti_spi_detach(device_t);
61 
62 #undef TI_SPI_DEBUG
63 #ifdef TI_SPI_DEBUG
64 #define	IRQSTATUSBITS							\
65 	"\020\1TX0_EMPTY\2TX0_UNDERFLOW\3RX0_FULL\4RX0_OVERFLOW"	\
66 	"\5TX1_EMPTY\6TX1_UNDERFLOW\7RX1_FULL\11TX2_EMPTY"		\
67 	"\12TX1_UNDERFLOW\13RX2_FULL\15TX3_EMPTY\16TX3_UNDERFLOW"	\
68 	"\17RX3_FULL\22EOW"
69 #define	CONFBITS							\
70 	"\020\1PHA\2POL\7EPOL\17DMAW\20DMAR\21DPE0\22DPE1\23IS"		\
71 	"\24TURBO\25FORCE\30SBE\31SBPOL\34FFEW\35FFER\36CLKG"
72 #define	STATBITS							\
73 	"\020\1RXS\2TXS\3EOT\4TXFFE\5TXFFF\6RXFFE\7RXFFFF"
74 #define	MODULCTRLBITS							\
75 	"\020\1SINGLE\2NOSPIEN\3SLAVE\4SYST\10MOA\11FDAA"
76 #define	CTRLBITS							\
77 	"\020\1ENABLED"
78 
79 static void
80 ti_spi_printr(device_t dev)
81 {
82 	int clk, conf, ctrl, div, i, j, wl;
83 	struct ti_spi_softc *sc;
84 	uint32_t reg;
85 
86 	sc = device_get_softc(dev);
87 	reg = TI_SPI_READ(sc, MCSPI_SYSCONFIG);
88 	device_printf(dev, "SYSCONFIG: %#x\n", reg);
89 	reg = TI_SPI_READ(sc, MCSPI_SYSSTATUS);
90 	device_printf(dev, "SYSSTATUS: %#x\n", reg);
91 	reg = TI_SPI_READ(sc, MCSPI_IRQSTATUS);
92 	device_printf(dev, "IRQSTATUS: 0x%b\n", reg, IRQSTATUSBITS);
93 	reg = TI_SPI_READ(sc, MCSPI_IRQENABLE);
94 	device_printf(dev, "IRQENABLE: 0x%b\n", reg, IRQSTATUSBITS);
95 	reg = TI_SPI_READ(sc, MCSPI_MODULCTRL);
96 	device_printf(dev, "MODULCTRL: 0x%b\n", reg, MODULCTRLBITS);
97 	for (i = 0; i < sc->sc_numcs; i++) {
98 		ctrl = TI_SPI_READ(sc, MCSPI_CTRL_CH(i));
99 		conf = TI_SPI_READ(sc, MCSPI_CONF_CH(i));
100 		device_printf(dev, "CH%dCONF: 0x%b\n", i, conf, CONFBITS);
101 		if (conf & MCSPI_CONF_CLKG) {
102 			div = (conf >> MCSPI_CONF_CLK_SHIFT) & MCSPI_CONF_CLK_MSK;
103 			div |= ((ctrl >> MCSPI_CTRL_EXTCLK_SHIFT) & MCSPI_CTRL_EXTCLK_MSK) << 4;
104 		} else {
105 			div = 1;
106 			j = (conf >> MCSPI_CONF_CLK_SHIFT) & MCSPI_CONF_CLK_MSK;
107 			while (j-- > 0)
108 				div <<= 1;
109 		}
110 		clk = TI_SPI_GCLK / div;
111 		wl = ((conf >> MCSPI_CONF_WL_SHIFT) & MCSPI_CONF_WL_MSK) + 1;
112 		device_printf(dev, "wordlen: %-2d clock: %d\n", wl, clk);
113 		reg = TI_SPI_READ(sc, MCSPI_STAT_CH(i));
114 		device_printf(dev, "CH%dSTAT: 0x%b\n", i, reg, STATBITS);
115 		device_printf(dev, "CH%dCTRL: 0x%b\n", i, ctrl, CTRLBITS);
116 	}
117 	reg = TI_SPI_READ(sc, MCSPI_XFERLEVEL);
118 	device_printf(dev, "XFERLEVEL: %#x\n", reg);
119 }
120 #endif
121 
122 static void
123 ti_spi_set_clock(struct ti_spi_softc *sc, int ch, int freq)
124 {
125 	uint32_t clkdiv, conf, div, extclk, reg;
126 
127 	clkdiv = TI_SPI_GCLK / freq;
128 	if (clkdiv > MCSPI_EXTCLK_MSK) {
129 		extclk = 0;
130 		clkdiv = 0;
131 		div = 1;
132 		while (TI_SPI_GCLK / div > freq && clkdiv <= 0xf) {
133 			clkdiv++;
134 			div <<= 1;
135 		}
136 		conf = clkdiv << MCSPI_CONF_CLK_SHIFT;
137 	} else {
138 		extclk = clkdiv >> 4;
139 		clkdiv &= MCSPI_CONF_CLK_MSK;
140 		conf = MCSPI_CONF_CLKG | clkdiv << MCSPI_CONF_CLK_SHIFT;
141 	}
142 
143 	reg = TI_SPI_READ(sc, MCSPI_CTRL_CH(ch));
144 	reg &= ~(MCSPI_CTRL_EXTCLK_MSK << MCSPI_CTRL_EXTCLK_SHIFT);
145 	reg |= extclk << MCSPI_CTRL_EXTCLK_SHIFT;
146 	TI_SPI_WRITE(sc, MCSPI_CTRL_CH(ch), reg);
147 
148 	reg = TI_SPI_READ(sc, MCSPI_CONF_CH(ch));
149 	reg &= ~(MCSPI_CONF_CLKG | MCSPI_CONF_CLK_MSK << MCSPI_CONF_CLK_SHIFT);
150 	TI_SPI_WRITE(sc, MCSPI_CONF_CH(ch), reg | conf);
151 }
152 
153 static int
154 ti_spi_probe(device_t dev)
155 {
156 
157 	if (!ofw_bus_status_okay(dev))
158 		return (ENXIO);
159 	if (!ofw_bus_is_compatible(dev, "ti,omap4-mcspi"))
160 		return (ENXIO);
161 
162 	device_set_desc(dev, "TI McSPI controller");
163 
164 	return (BUS_PROBE_DEFAULT);
165 }
166 
167 static int
168 ti_spi_attach(device_t dev)
169 {
170 	int clk_id, err, i, rid, timeout;
171 	struct ti_spi_softc *sc;
172 	uint32_t rev;
173 
174 	sc = device_get_softc(dev);
175 	sc->sc_dev = dev;
176 
177 	/*
178 	 * Get the MMCHS device id from FDT.  If it's not there use the newbus
179 	 * unit number (which will work as long as the devices are in order and
180 	 * none are skipped in the fdt).  Note that this is a property we made
181 	 * up and added in freebsd, it doesn't exist in the published bindings.
182 	 */
183 	clk_id = ti_hwmods_get_clock(dev);
184 	if (clk_id == INVALID_CLK_IDENT) {
185 		device_printf(dev,
186 		    "failed to get clock based on hwmods property\n");
187 		return (EINVAL);
188 	}
189 
190 	/* Activate the McSPI module. */
191 	err = ti_prcm_clk_enable(clk_id);
192 	if (err) {
193 		device_printf(dev, "Error: failed to activate source clock\n");
194 		return (err);
195 	}
196 
197 	/* Get the number of available channels. */
198 	if ((OF_getencprop(ofw_bus_get_node(dev), "ti,spi-num-cs",
199 	    &sc->sc_numcs, sizeof(sc->sc_numcs))) <= 0) {
200 		sc->sc_numcs = 2;
201 	}
202 
203 	rid = 0;
204 	sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
205 	    RF_ACTIVE);
206 	if (!sc->sc_mem_res) {
207 		device_printf(dev, "cannot allocate memory window\n");
208 		return (ENXIO);
209 	}
210 
211 	sc->sc_bst = rman_get_bustag(sc->sc_mem_res);
212 	sc->sc_bsh = rman_get_bushandle(sc->sc_mem_res);
213 
214 	rid = 0;
215 	sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
216 	    RF_ACTIVE);
217 	if (!sc->sc_irq_res) {
218 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
219 		device_printf(dev, "cannot allocate interrupt\n");
220 		return (ENXIO);
221 	}
222 
223 	/* Hook up our interrupt handler. */
224 	if (bus_setup_intr(dev, sc->sc_irq_res, INTR_TYPE_MISC | INTR_MPSAFE,
225 	    NULL, ti_spi_intr, sc, &sc->sc_intrhand)) {
226 		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq_res);
227 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
228 		device_printf(dev, "cannot setup the interrupt handler\n");
229 		return (ENXIO);
230 	}
231 
232 	mtx_init(&sc->sc_mtx, "ti_spi", NULL, MTX_DEF);
233 
234 	/* Issue a softreset to the controller */
235 	TI_SPI_WRITE(sc, MCSPI_SYSCONFIG, MCSPI_SYSCONFIG_SOFTRESET);
236 	timeout = 1000;
237 	while (!(TI_SPI_READ(sc, MCSPI_SYSSTATUS) &
238 	    MCSPI_SYSSTATUS_RESETDONE)) {
239 		if (--timeout == 0) {
240 			device_printf(dev,
241 			    "Error: Controller reset operation timed out\n");
242 			ti_spi_detach(dev);
243 			return (ENXIO);
244 		}
245 		DELAY(100);
246 	}
247 
248 	/* Print the McSPI module revision. */
249 	rev = TI_SPI_READ(sc, MCSPI_REVISION);
250 	device_printf(dev,
251 	    "scheme: %#x func: %#x rtl: %d rev: %d.%d custom rev: %d\n",
252 	    (rev >> MCSPI_REVISION_SCHEME_SHIFT) & MCSPI_REVISION_SCHEME_MSK,
253 	    (rev >> MCSPI_REVISION_FUNC_SHIFT) & MCSPI_REVISION_FUNC_MSK,
254 	    (rev >> MCSPI_REVISION_RTL_SHIFT) & MCSPI_REVISION_RTL_MSK,
255 	    (rev >> MCSPI_REVISION_MAJOR_SHIFT) & MCSPI_REVISION_MAJOR_MSK,
256 	    (rev >> MCSPI_REVISION_MINOR_SHIFT) & MCSPI_REVISION_MINOR_MSK,
257 	    (rev >> MCSPI_REVISION_CUSTOM_SHIFT) & MCSPI_REVISION_CUSTOM_MSK);
258 
259 	/* Set Master mode, single channel. */
260 	TI_SPI_WRITE(sc, MCSPI_MODULCTRL, MCSPI_MODULCTRL_SINGLE);
261 
262 	/* Clear pending interrupts and disable interrupts. */
263 	TI_SPI_WRITE(sc, MCSPI_IRQENABLE, 0x0);
264 	TI_SPI_WRITE(sc, MCSPI_IRQSTATUS, 0xffff);
265 
266 	for (i = 0; i < sc->sc_numcs; i++) {
267 		/*
268 		 * Default to SPI mode 0, CS active low, 8 bits word length and
269 		 * 500kHz clock.
270 		 */
271 		TI_SPI_WRITE(sc, MCSPI_CONF_CH(i),
272 		    MCSPI_CONF_DPE0 | MCSPI_CONF_EPOL |
273 		    (8 - 1) << MCSPI_CONF_WL_SHIFT);
274 		/* Set initial clock - 500kHz. */
275 		ti_spi_set_clock(sc, i, 500000);
276 	}
277 
278 #ifdef	TI_SPI_DEBUG
279 	ti_spi_printr(dev);
280 #endif
281 
282 	device_add_child(dev, "spibus", -1);
283 
284 	return (bus_generic_attach(dev));
285 }
286 
287 static int
288 ti_spi_detach(device_t dev)
289 {
290 	struct ti_spi_softc *sc;
291 
292 	sc = device_get_softc(dev);
293 
294 	/* Clear pending interrupts and disable interrupts. */
295 	TI_SPI_WRITE(sc, MCSPI_IRQENABLE, 0);
296 	TI_SPI_WRITE(sc, MCSPI_IRQSTATUS, 0xffff);
297 
298 	/* Reset controller. */
299 	TI_SPI_WRITE(sc, MCSPI_SYSCONFIG, MCSPI_SYSCONFIG_SOFTRESET);
300 
301 	bus_generic_detach(dev);
302 
303 	mtx_destroy(&sc->sc_mtx);
304 	if (sc->sc_intrhand)
305 		bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intrhand);
306 	if (sc->sc_irq_res)
307 		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq_res);
308 	if (sc->sc_mem_res)
309 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
310 
311 	return (0);
312 }
313 
314 static int
315 ti_spi_fill_fifo(struct ti_spi_softc *sc)
316 {
317 	int bytes, timeout;
318 	struct spi_command *cmd;
319 	uint32_t written;
320 	uint8_t *data;
321 
322 	cmd = sc->sc_cmd;
323 	bytes = min(sc->sc_len - sc->sc_written, sc->sc_fifolvl);
324 	while (bytes-- > 0) {
325 		data = (uint8_t *)cmd->tx_cmd;
326 		written = sc->sc_written++;
327 		if (written >= cmd->tx_cmd_sz) {
328 			data = (uint8_t *)cmd->tx_data;
329 			written -= cmd->tx_cmd_sz;
330 		}
331 		if (sc->sc_fifolvl == 1) {
332 			/* FIFO disabled. */
333 			timeout = 1000;
334 			while (--timeout > 0 && (TI_SPI_READ(sc,
335 			    MCSPI_STAT_CH(sc->sc_cs)) & MCSPI_STAT_TXS) == 0) {
336 				DELAY(100);
337 			}
338 			if (timeout == 0)
339 				return (-1);
340 		}
341 		TI_SPI_WRITE(sc, MCSPI_TX_CH(sc->sc_cs), data[written]);
342 	}
343 
344 	return (0);
345 }
346 
347 static int
348 ti_spi_drain_fifo(struct ti_spi_softc *sc)
349 {
350 	int bytes, timeout;
351 	struct spi_command *cmd;
352 	uint32_t read;
353 	uint8_t *data;
354 
355 	cmd = sc->sc_cmd;
356 	bytes = min(sc->sc_len - sc->sc_read, sc->sc_fifolvl);
357 	while (bytes-- > 0) {
358 		data = (uint8_t *)cmd->rx_cmd;
359 		read = sc->sc_read++;
360 		if (read >= cmd->rx_cmd_sz) {
361 			data = (uint8_t *)cmd->rx_data;
362 			read -= cmd->rx_cmd_sz;
363 		}
364 		if (sc->sc_fifolvl == 1) {
365 			/* FIFO disabled. */
366 			timeout = 1000;
367 			while (--timeout > 0 && (TI_SPI_READ(sc,
368 			    MCSPI_STAT_CH(sc->sc_cs)) & MCSPI_STAT_RXS) == 0) {
369 				DELAY(100);
370 			}
371 			if (timeout == 0)
372 				return (-1);
373 		}
374 		data[read] = TI_SPI_READ(sc, MCSPI_RX_CH(sc->sc_cs));
375 	}
376 
377 	return (0);
378 }
379 
380 static void
381 ti_spi_intr(void *arg)
382 {
383 	int eow;
384 	struct ti_spi_softc *sc;
385 	uint32_t status;
386 
387 	eow = 0;
388 	sc = (struct ti_spi_softc *)arg;
389 	TI_SPI_LOCK(sc);
390 	status = TI_SPI_READ(sc, MCSPI_IRQSTATUS);
391 
392 	/*
393 	 * No new TX_empty or RX_full event will be asserted while the CPU has
394 	 * not performed the number of writes or reads defined by
395 	 * MCSPI_XFERLEVEL[AEL] and MCSPI_XFERLEVEL[AFL].  It is responsibility
396 	 * of CPU perform the right number of writes and reads.
397 	 */
398 	if (status & MCSPI_IRQ_TX0_EMPTY)
399 		ti_spi_fill_fifo(sc);
400 	if (status & MCSPI_IRQ_RX0_FULL)
401 		ti_spi_drain_fifo(sc);
402 
403 	if (status & MCSPI_IRQ_EOW)
404 		eow = 1;
405 
406 	/* Clear interrupt status. */
407 	TI_SPI_WRITE(sc, MCSPI_IRQSTATUS, status);
408 
409 	/* Check for end of transfer. */
410 	if (sc->sc_written == sc->sc_len && sc->sc_read == sc->sc_len) {
411 		sc->sc_flags |= TI_SPI_DONE;
412 		wakeup(sc->sc_dev);
413 	}
414 
415 	TI_SPI_UNLOCK(sc);
416 }
417 
418 static int
419 ti_spi_pio_transfer(struct ti_spi_softc *sc)
420 {
421 
422 	while (sc->sc_len - sc->sc_written > 0) {
423 		if (ti_spi_fill_fifo(sc) == -1)
424 			return (EIO);
425 		if (ti_spi_drain_fifo(sc) == -1)
426 			return (EIO);
427 	}
428 
429 	return (0);
430 }
431 
432 static int
433 ti_spi_gcd(int a, int b)
434 {
435 	int m;
436 
437 	while ((m = a % b) != 0) {
438 		a = b;
439 		b = m;
440 	}
441 
442 	return (b);
443 }
444 
445 static int
446 ti_spi_transfer(device_t dev, device_t child, struct spi_command *cmd)
447 {
448 	int cs, err;
449 	struct ti_spi_softc *sc;
450 	uint32_t reg;
451 
452 	sc = device_get_softc(dev);
453 
454 	KASSERT(cmd->tx_cmd_sz == cmd->rx_cmd_sz,
455 	    ("TX/RX command sizes should be equal"));
456 	KASSERT(cmd->tx_data_sz == cmd->rx_data_sz,
457 	    ("TX/RX data sizes should be equal"));
458 
459 	/* Get the proper chip select for this child. */
460 	spibus_get_cs(child, &cs);
461 	if (cs < 0 || cs > sc->sc_numcs) {
462 		device_printf(dev, "Invalid chip select %d requested by %s\n",
463 		    cs, device_get_nameunit(child));
464 		return (EINVAL);
465 	}
466 
467 	TI_SPI_LOCK(sc);
468 
469 	/* If the controller is in use wait until it is available. */
470 	while (sc->sc_flags & TI_SPI_BUSY)
471 		mtx_sleep(dev, &sc->sc_mtx, 0, "ti_spi", 0);
472 
473 	/* Now we have control over SPI controller. */
474 	sc->sc_flags = TI_SPI_BUSY;
475 
476 	/* Save the SPI command data. */
477 	sc->sc_cs = cs;
478 	sc->sc_cmd = cmd;
479 	sc->sc_read = 0;
480 	sc->sc_written = 0;
481 	sc->sc_len = cmd->tx_cmd_sz + cmd->tx_data_sz;
482 	sc->sc_fifolvl = ti_spi_gcd(sc->sc_len, TI_SPI_FIFOSZ);
483 	if (sc->sc_fifolvl < 2 || sc->sc_len > 0xffff)
484 		sc->sc_fifolvl = 1;	/* FIFO disabled. */
485 	/* Disable FIFO for now. */
486 	sc->sc_fifolvl = 1;
487 
488 	/* Use a safe clock - 500kHz. */
489 	ti_spi_set_clock(sc, sc->sc_cs, 500000);
490 
491 	/* Disable the FIFO. */
492 	TI_SPI_WRITE(sc, MCSPI_XFERLEVEL, 0);
493 
494 	/* 8 bits word, d0 miso, d1 mosi, mode 0 and CS active low. */
495 	reg = TI_SPI_READ(sc, MCSPI_CONF_CH(sc->sc_cs));
496 	reg &= ~(MCSPI_CONF_FFER | MCSPI_CONF_FFEW | MCSPI_CONF_SBPOL |
497 	    MCSPI_CONF_SBE | MCSPI_CONF_TURBO | MCSPI_CONF_IS |
498 	    MCSPI_CONF_DPE1 | MCSPI_CONF_DPE0 | MCSPI_CONF_DMAR |
499 	    MCSPI_CONF_DMAW | MCSPI_CONF_EPOL);
500 	reg |= MCSPI_CONF_DPE0 | MCSPI_CONF_EPOL | MCSPI_CONF_WL8BITS;
501 	TI_SPI_WRITE(sc, MCSPI_CONF_CH(sc->sc_cs), reg);
502 
503 #if 0
504 	/* Enable channel interrupts. */
505 	reg = TI_SPI_READ(sc, MCSPI_IRQENABLE);
506 	reg |= 0xf;
507 	TI_SPI_WRITE(sc, MCSPI_IRQENABLE, reg);
508 #endif
509 
510 	/* Start the transfer. */
511 	reg = TI_SPI_READ(sc, MCSPI_CTRL_CH(sc->sc_cs));
512 	TI_SPI_WRITE(sc, MCSPI_CTRL_CH(sc->sc_cs), reg | MCSPI_CTRL_ENABLE);
513 
514 	/* Force CS on. */
515 	reg = TI_SPI_READ(sc, MCSPI_CONF_CH(sc->sc_cs));
516 	TI_SPI_WRITE(sc, MCSPI_CONF_CH(sc->sc_cs), reg |= MCSPI_CONF_FORCE);
517 
518 	err = 0;
519 	if (sc->sc_fifolvl == 1)
520 		err = ti_spi_pio_transfer(sc);
521 
522 	/* Force CS off. */
523 	reg = TI_SPI_READ(sc, MCSPI_CONF_CH(sc->sc_cs));
524 	reg &= ~MCSPI_CONF_FORCE;
525 	TI_SPI_WRITE(sc, MCSPI_CONF_CH(sc->sc_cs), reg);
526 
527 	/* Disable IRQs. */
528 	reg = TI_SPI_READ(sc, MCSPI_IRQENABLE);
529 	reg &= ~0xf;
530 	TI_SPI_WRITE(sc, MCSPI_IRQENABLE, reg);
531 	TI_SPI_WRITE(sc, MCSPI_IRQSTATUS, 0xf);
532 
533 	/* Disable the SPI channel. */
534 	reg = TI_SPI_READ(sc, MCSPI_CTRL_CH(sc->sc_cs));
535 	reg &= ~MCSPI_CTRL_ENABLE;
536 	TI_SPI_WRITE(sc, MCSPI_CTRL_CH(sc->sc_cs), reg);
537 
538 	/* Disable FIFO. */
539 	reg = TI_SPI_READ(sc, MCSPI_CONF_CH(sc->sc_cs));
540 	reg &= ~(MCSPI_CONF_FFER | MCSPI_CONF_FFEW);
541 	TI_SPI_WRITE(sc, MCSPI_CONF_CH(sc->sc_cs), reg);
542 
543 	/* Release the controller and wakeup the next thread waiting for it. */
544 	sc->sc_flags = 0;
545 	wakeup_one(dev);
546 	TI_SPI_UNLOCK(sc);
547 
548 	return (err);
549 }
550 
551 static phandle_t
552 ti_spi_get_node(device_t bus, device_t dev)
553 {
554 
555 	/* Share controller node with spibus. */
556 	return (ofw_bus_get_node(bus));
557 }
558 
559 static device_method_t ti_spi_methods[] = {
560 	/* Device interface */
561 	DEVMETHOD(device_probe,		ti_spi_probe),
562 	DEVMETHOD(device_attach,	ti_spi_attach),
563 	DEVMETHOD(device_detach,	ti_spi_detach),
564 
565 	/* SPI interface */
566 	DEVMETHOD(spibus_transfer,	ti_spi_transfer),
567 
568 	/* ofw_bus interface */
569 	DEVMETHOD(ofw_bus_get_node,	ti_spi_get_node),
570 
571 	DEVMETHOD_END
572 };
573 
574 static devclass_t ti_spi_devclass;
575 
576 static driver_t ti_spi_driver = {
577 	"spi",
578 	ti_spi_methods,
579 	sizeof(struct ti_spi_softc),
580 };
581 
582 DRIVER_MODULE(ti_spi, simplebus, ti_spi_driver, ti_spi_devclass, 0, 0);
583