2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2006 M. Warner Losh.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 #include "opt_platform.h"
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include <sys/param.h>
34 #include <sys/systm.h>
37 #include <sys/kernel.h>
40 #include <sys/malloc.h>
41 #include <sys/module.h>
42 #include <sys/mutex.h>
44 #include <machine/bus.h>
46 #include <arm/at91/at91_twireg.h>
47 #include <arm/at91/at91var.h>
49 #include <dev/iicbus/iiconf.h>
50 #include <dev/iicbus/iicbus.h>
51 #include "iicbus_if.h"
54 #include <dev/ofw/ofw_bus.h>
55 #include <dev/ofw/ofw_bus_subr.h>
58 #define TWI_SLOW_CLOCK 1500
59 #define TWI_FAST_CLOCK 45000
60 #define TWI_FASTEST_CLOCK 90000
64 device_t dev; /* Myself */
65 void *intrhand; /* Interrupt handle */
66 struct resource *irq_res; /* IRQ resource */
67 struct resource *mem_res; /* Memory resource */
68 struct mtx sc_mtx; /* basically a perimeter lock */
69 volatile uint32_t flags;
76 static inline uint32_t
77 RD4(struct at91_twi_softc *sc, bus_size_t off)
80 return bus_read_4(sc->mem_res, off);
84 WR4(struct at91_twi_softc *sc, bus_size_t off, uint32_t val)
87 bus_write_4(sc->mem_res, off, val);
90 #define AT91_TWI_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx)
91 #define AT91_TWI_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx)
92 #define AT91_TWI_LOCK_INIT(_sc) \
93 mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->dev), \
95 #define AT91_TWI_LOCK_DESTROY(_sc) mtx_destroy(&_sc->sc_mtx);
96 #define AT91_TWI_ASSERT_LOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_OWNED);
97 #define AT91_TWI_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_NOTOWNED);
98 #define TWI_DEF_CLK 100000
100 static devclass_t at91_twi_devclass;
102 /* bus entry points */
104 static int at91_twi_probe(device_t dev);
105 static int at91_twi_attach(device_t dev);
106 static int at91_twi_detach(device_t dev);
107 static void at91_twi_intr(void *);
109 /* helper routines */
110 static int at91_twi_activate(device_t dev);
111 static void at91_twi_deactivate(device_t dev);
114 at91_twi_probe(device_t dev)
117 /* XXXX need a whole list, since there's at least 4 different ones */
118 if (!ofw_bus_is_compatible(dev, "atmel,at91sam9g20-i2c"))
121 device_set_desc(dev, "TWI");
126 at91_twi_attach(device_t dev)
128 struct at91_twi_softc *sc = device_get_softc(dev);
132 err = at91_twi_activate(dev);
136 AT91_TWI_LOCK_INIT(sc);
140 * Disable devices need to hold their resources, so return now and not attach
141 * the iicbus, setup interrupt handlers, etc.
143 if (!ofw_bus_status_okay(dev))
148 * Activate the interrupt
150 err = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_MISC | INTR_MPSAFE,
151 NULL, at91_twi_intr, sc, &sc->intrhand);
153 AT91_TWI_LOCK_DESTROY(sc);
156 sc->cwgr = TWI_CWGR_CKDIV(8 * at91_master_clock / TWI_FASTEST_CLOCK) |
157 TWI_CWGR_CHDIV(TWI_CWGR_DIV(TWI_DEF_CLK)) |
158 TWI_CWGR_CLDIV(TWI_CWGR_DIV(TWI_DEF_CLK));
159 WR4(sc, TWI_CR, TWI_CR_SWRST);
160 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
161 WR4(sc, TWI_CWGR, sc->cwgr);
163 if ((sc->iicbus = device_add_child(dev, "iicbus", -1)) == NULL)
164 device_printf(dev, "could not allocate iicbus instance\n");
165 /* Probe and attach the iicbus when interrupts are available. */
166 config_intrhook_oneshot((ich_func_t)bus_generic_attach, dev);
169 at91_twi_deactivate(dev);
174 at91_twi_detach(device_t dev)
176 struct at91_twi_softc *sc;
179 sc = device_get_softc(dev);
180 at91_twi_deactivate(dev);
181 if (sc->iicbus && (rv = device_delete_child(dev, sc->iicbus)) != 0)
184 AT91_TWI_LOCK_DESTROY(sc);
190 at91_twi_activate(device_t dev)
192 struct at91_twi_softc *sc;
195 sc = device_get_softc(dev);
197 sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
199 if (sc->mem_res == NULL)
202 sc->irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
204 if (sc->irq_res == NULL)
208 at91_twi_deactivate(dev);
213 at91_twi_deactivate(device_t dev)
215 struct at91_twi_softc *sc;
217 sc = device_get_softc(dev);
219 bus_teardown_intr(dev, sc->irq_res, sc->intrhand);
221 bus_generic_detach(sc->dev);
223 bus_release_resource(dev, SYS_RES_MEMORY,
224 rman_get_rid(sc->mem_res), sc->mem_res);
227 bus_release_resource(dev, SYS_RES_IRQ,
228 rman_get_rid(sc->irq_res), sc->irq_res);
234 at91_twi_intr(void *xsc)
236 struct at91_twi_softc *sc = xsc;
239 status = RD4(sc, TWI_SR);
243 sc->flags |= status & (TWI_SR_OVRE | TWI_SR_UNRE | TWI_SR_NACK);
244 if (status & TWI_SR_RXRDY)
245 sc->flags |= TWI_SR_RXRDY;
246 if (status & TWI_SR_TXRDY)
247 sc->flags |= TWI_SR_TXRDY;
248 if (status & TWI_SR_TXCOMP)
249 sc->flags |= TWI_SR_TXCOMP;
250 WR4(sc, TWI_IDR, status);
257 at91_twi_wait(struct at91_twi_softc *sc, uint32_t bit)
260 int counter = 100000;
263 AT91_TWI_ASSERT_LOCKED(sc);
264 while (!((sr = RD4(sc, TWI_SR)) & bit) && counter-- > 0 &&
269 else if (sr & TWI_SR_NACK)
270 err = ENXIO; // iic nack convention
275 at91_twi_rst_card(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
277 struct at91_twi_softc *sc;
280 sc = device_get_softc(dev);
283 *oldaddr = sc->twi_addr;
287 * speeds are for 1.5kb/s, 45kb/s and 90kb/s.
291 clk = TWI_SLOW_CLOCK;
295 clk = TWI_FAST_CLOCK;
301 clk = TWI_FASTEST_CLOCK;
304 sc->cwgr = TWI_CWGR_CKDIV(1) | TWI_CWGR_CHDIV(TWI_CWGR_DIV(clk)) |
305 TWI_CWGR_CLDIV(TWI_CWGR_DIV(clk));
306 WR4(sc, TWI_CR, TWI_CR_SWRST);
307 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
308 WR4(sc, TWI_CWGR, sc->cwgr);
315 at91_twi_callback(device_t dev, int index, caddr_t data)
320 case IIC_REQUEST_BUS:
323 case IIC_RELEASE_BUS:
334 at91_twi_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
336 struct at91_twi_softc *sc;
342 sc = device_get_softc(dev);
345 for (i = 0; i < nmsgs; i++) {
347 * The linux atmel driver doesn't use the internal device
348 * address feature of twi. A separate i2c message needs to
349 * be written to use this.
350 * See http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2004-September/024411.html
351 * for details. Upon reflection, we could use this as an
352 * optimization, but it is unclear the code bloat will
353 * result in faster/better operations.
355 rdwr = (msgs[i].flags & IIC_M_RD) ? TWI_MMR_MREAD : 0;
356 WR4(sc, TWI_MMR, TWI_MMR_DADR(msgs[i].slave) | rdwr);
359 /* zero byte transfers aren't allowed */
360 if (len == 0 || buf == NULL) {
364 if (len == 1 && msgs[i].flags & IIC_M_RD)
365 WR4(sc, TWI_CR, TWI_CR_START | TWI_CR_STOP);
367 WR4(sc, TWI_CR, TWI_CR_START);
368 if (msgs[i].flags & IIC_M_RD) {
369 sr = RD4(sc, TWI_SR);
370 while (!(sr & TWI_SR_TXCOMP)) {
371 if ((sr = RD4(sc, TWI_SR)) & TWI_SR_RXRDY) {
373 *buf++ = RD4(sc, TWI_RHR) & 0xff;
375 WR4(sc, TWI_CR, TWI_CR_STOP);
378 if (len > 0 || (sr & TWI_SR_NACK)) {
379 err = ENXIO; // iic nack convention
384 if ((err = at91_twi_wait(sc, TWI_SR_TXRDY)))
386 WR4(sc, TWI_THR, *buf++);
388 WR4(sc, TWI_CR, TWI_CR_STOP);
390 if ((err = at91_twi_wait(sc, TWI_SR_TXCOMP)))
395 WR4(sc, TWI_CR, TWI_CR_SWRST);
396 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
397 WR4(sc, TWI_CWGR, sc->cwgr);
403 static device_method_t at91_twi_methods[] = {
404 /* Device interface */
405 DEVMETHOD(device_probe, at91_twi_probe),
406 DEVMETHOD(device_attach, at91_twi_attach),
407 DEVMETHOD(device_detach, at91_twi_detach),
409 /* iicbus interface */
410 DEVMETHOD(iicbus_callback, at91_twi_callback),
411 DEVMETHOD(iicbus_reset, at91_twi_rst_card),
412 DEVMETHOD(iicbus_transfer, at91_twi_transfer),
416 static driver_t at91_twi_driver = {
419 sizeof(struct at91_twi_softc),
423 DRIVER_MODULE(at91_twi, simplebus, at91_twi_driver, at91_twi_devclass, NULL,
426 DRIVER_MODULE(at91_twi, atmelarm, at91_twi_driver, at91_twi_devclass, NULL,
429 DRIVER_MODULE(iicbus, at91_twi, iicbus_driver, iicbus_devclass, NULL, NULL);
430 MODULE_DEPEND(at91_twi, iicbus, 1, 1, 1);