2 * Copyright (c) 2006 M. Warner Losh. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
29 #include <sys/param.h>
30 #include <sys/systm.h>
33 #include <sys/kernel.h>
36 #include <sys/malloc.h>
37 #include <sys/module.h>
38 #include <sys/mutex.h>
40 #include <machine/bus.h>
42 #include <arm/at91/at91rm92reg.h>
43 #include <arm/at91/at91_twireg.h>
44 #include <arm/at91/at91var.h>
46 #include <dev/iicbus/iiconf.h>
47 #include <dev/iicbus/iicbus.h>
48 #include "iicbus_if.h"
50 #define TWI_SLOW_CLOCK 1500
51 #define TWI_FAST_CLOCK 45000
52 #define TWI_FASTEST_CLOCK 90000
56 device_t dev; /* Myself */
57 void *intrhand; /* Interrupt handle */
58 struct resource *irq_res; /* IRQ resource */
59 struct resource *mem_res; /* Memory resource */
60 struct mtx sc_mtx; /* basically a perimeter lock */
61 volatile uint32_t flags;
68 static inline uint32_t
69 RD4(struct at91_twi_softc *sc, bus_size_t off)
71 return bus_read_4(sc->mem_res, off);
75 WR4(struct at91_twi_softc *sc, bus_size_t off, uint32_t val)
77 bus_write_4(sc->mem_res, off, val);
80 #define AT91_TWI_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx)
81 #define AT91_TWI_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx)
82 #define AT91_TWI_LOCK_INIT(_sc) \
83 mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->dev), \
85 #define AT91_TWI_LOCK_DESTROY(_sc) mtx_destroy(&_sc->sc_mtx);
86 #define AT91_TWI_ASSERT_LOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_OWNED);
87 #define AT91_TWI_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_NOTOWNED);
88 #define TWI_DEF_CLK 100000
90 static devclass_t at91_twi_devclass;
92 /* bus entry points */
94 static int at91_twi_probe(device_t dev);
95 static int at91_twi_attach(device_t dev);
96 static int at91_twi_detach(device_t dev);
97 static void at91_twi_intr(void *);
100 static int at91_twi_activate(device_t dev);
101 static void at91_twi_deactivate(device_t dev);
104 at91_twi_probe(device_t dev)
106 device_set_desc(dev, "TWI");
111 at91_twi_attach(device_t dev)
113 struct at91_twi_softc *sc = device_get_softc(dev);
117 err = at91_twi_activate(dev);
121 AT91_TWI_LOCK_INIT(sc);
124 * Activate the interrupt
126 err = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_MISC | INTR_MPSAFE,
127 NULL, at91_twi_intr, sc, &sc->intrhand);
129 AT91_TWI_LOCK_DESTROY(sc);
132 sc->cwgr = TWI_CWGR_CKDIV(8 * at91_master_clock / TWI_FASTEST_CLOCK) |
133 TWI_CWGR_CHDIV(TWI_CWGR_DIV(TWI_DEF_CLK)) |
134 TWI_CWGR_CLDIV(TWI_CWGR_DIV(TWI_DEF_CLK));
135 WR4(sc, TWI_CR, TWI_CR_SWRST);
136 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
137 WR4(sc, TWI_CWGR, sc->cwgr);
139 if ((sc->iicbus = device_add_child(dev, "iicbus", -1)) == NULL)
140 device_printf(dev, "could not allocate iicbus instance\n");
141 /* probe and attach the iicbus */
142 bus_generic_attach(dev);
145 at91_twi_deactivate(dev);
150 at91_twi_detach(device_t dev)
152 struct at91_twi_softc *sc;
155 sc = device_get_softc(dev);
156 at91_twi_deactivate(dev);
157 if (sc->iicbus && (rv = device_delete_child(dev, sc->iicbus)) != 0)
160 AT91_TWI_LOCK_DESTROY(sc);
166 at91_twi_activate(device_t dev)
168 struct at91_twi_softc *sc;
171 sc = device_get_softc(dev);
173 sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
175 if (sc->mem_res == NULL)
178 sc->irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
180 if (sc->irq_res == NULL)
184 at91_twi_deactivate(dev);
189 at91_twi_deactivate(device_t dev)
191 struct at91_twi_softc *sc;
193 sc = device_get_softc(dev);
195 bus_teardown_intr(dev, sc->irq_res, sc->intrhand);
197 bus_generic_detach(sc->dev);
199 bus_release_resource(dev, SYS_RES_MEMORY,
200 rman_get_rid(sc->mem_res), sc->mem_res);
203 bus_release_resource(dev, SYS_RES_IRQ,
204 rman_get_rid(sc->irq_res), sc->irq_res);
210 at91_twi_intr(void *xsc)
212 struct at91_twi_softc *sc = xsc;
215 status = RD4(sc, TWI_SR);
219 sc->flags |= status & (TWI_SR_OVRE | TWI_SR_UNRE | TWI_SR_NACK);
220 if (status & TWI_SR_RXRDY)
221 sc->flags |= TWI_SR_RXRDY;
222 if (status & TWI_SR_TXRDY)
223 sc->flags |= TWI_SR_TXRDY;
224 if (status & TWI_SR_TXCOMP)
225 sc->flags |= TWI_SR_TXCOMP;
226 WR4(sc, TWI_IDR, status);
233 at91_twi_wait(struct at91_twi_softc *sc, uint32_t bit)
236 int counter = 100000;
239 AT91_TWI_ASSERT_LOCKED(sc);
240 while (!((sr = RD4(sc, TWI_SR)) & bit) && counter-- > 0 &&
245 else if (sr & TWI_SR_NACK)
246 err = ENXIO; // iic nack convention
251 at91_twi_rst_card(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
253 struct at91_twi_softc *sc;
256 sc = device_get_softc(dev);
259 *oldaddr = sc->twi_addr;
263 * speeds are for 1.5kb/s, 45kb/s and 90kb/s.
267 clk = TWI_SLOW_CLOCK;
271 clk = TWI_FAST_CLOCK;
277 clk = TWI_FASTEST_CLOCK;
280 sc->cwgr = TWI_CWGR_CKDIV(1) | TWI_CWGR_CHDIV(TWI_CWGR_DIV(clk)) |
281 TWI_CWGR_CLDIV(TWI_CWGR_DIV(clk));
282 WR4(sc, TWI_CR, TWI_CR_SWRST);
283 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
284 WR4(sc, TWI_CWGR, sc->cwgr);
285 printf("setting cwgr to %#x\n", sc->cwgr);
292 at91_twi_callback(device_t dev, int index, caddr_t data)
297 case IIC_REQUEST_BUS:
300 case IIC_RELEASE_BUS:
311 at91_twi_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
313 struct at91_twi_softc *sc;
319 sc = device_get_softc(dev);
322 for (i = 0; i < nmsgs; i++) {
324 * The linux atmel driver doesn't use the internal device
325 * address feature of twi. A separate i2c message needs to
326 * be written to use this.
327 * See http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2004-September/024411.html
328 * for details. Upon reflection, we could use this as an
329 * optimization, but it is unclear the code bloat will
330 * result in faster/better operations.
332 rdwr = (msgs[i].flags & IIC_M_RD) ? TWI_MMR_MREAD : 0;
333 WR4(sc, TWI_MMR, TWI_MMR_DADR(msgs[i].slave) | rdwr);
336 /* zero byte transfers aren't allowed */
337 if (len == 0 || buf == NULL) {
342 WR4(sc, TWI_CR, TWI_CR_START | TWI_CR_STOP);
344 WR4(sc, TWI_CR, TWI_CR_START);
345 if (msgs[i].flags & IIC_M_RD) {
346 sr = RD4(sc, TWI_SR);
347 while (!(sr & TWI_SR_TXCOMP)) {
348 if ((sr = RD4(sc, TWI_SR)) & TWI_SR_RXRDY) {
350 *buf++ = RD4(sc, TWI_RHR) & 0xff;
351 if (len == 0 && msgs[i].len != 1)
352 WR4(sc, TWI_CR, TWI_CR_STOP);
355 if (len > 0 || (sr & TWI_SR_NACK)) {
356 err = ENXIO; // iic nack convention
361 if (len == 0 && msgs[i].len != 1)
362 WR4(sc, TWI_CR, TWI_CR_STOP);
363 if ((err = at91_twi_wait(sc, TWI_SR_TXRDY)))
365 WR4(sc, TWI_THR, *buf++);
368 if ((err = at91_twi_wait(sc, TWI_SR_TXCOMP)))
373 WR4(sc, TWI_CR, TWI_CR_SWRST);
374 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
375 WR4(sc, TWI_CWGR, sc->cwgr);
381 static device_method_t at91_twi_methods[] = {
382 /* Device interface */
383 DEVMETHOD(device_probe, at91_twi_probe),
384 DEVMETHOD(device_attach, at91_twi_attach),
385 DEVMETHOD(device_detach, at91_twi_detach),
387 /* iicbus interface */
388 DEVMETHOD(iicbus_callback, at91_twi_callback),
389 DEVMETHOD(iicbus_reset, at91_twi_rst_card),
390 DEVMETHOD(iicbus_transfer, at91_twi_transfer),
394 static driver_t at91_twi_driver = {
397 sizeof(struct at91_twi_softc),
400 DRIVER_MODULE(at91_twi, atmelarm, at91_twi_driver, at91_twi_devclass, 0, 0);
401 DRIVER_MODULE(iicbus, at91_twi, iicbus_driver, iicbus_devclass, 0, 0);
402 MODULE_DEPEND(at91_twi, iicbus, 1, 1, 1);