2 * Copyright (c) 1998, 2001 Nicolas Souchu
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
26 * $FreeBSD: head/sys/dev/iicbus/iicbb.c 232365 2012-03-01 20:58:20Z kan $
30 * Generic I2C bit-banging code
40 * From Linux I2C generic interface
41 * (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
45 #include <sys/param.h>
46 #include <sys/kernel.h>
47 #include <sys/systm.h>
48 #include <sys/module.h>
52 #include <bus/iicbus/iiconf.h>
53 #include <bus/iicbus/iicbus.h>
55 #include <bus/smbus/smbconf.h>
57 #include "iicbus_if.h"
62 int udelay
; /* signal toggle delay in usec */
65 static int iicbb_attach(device_t
);
66 static void iicbb_child_detached(device_t
, device_t
);
67 static int iicbb_detach(device_t
);
68 static int iicbb_print_child(device_t
, device_t
);
69 static int iicbb_probe(device_t
);
71 static int iicbb_callback(device_t
, int, caddr_t
);
72 static int iicbb_start(device_t
, u_char
, int);
73 static int iicbb_stop(device_t
);
74 static int iicbb_write(device_t
, const char *, int, int *, int);
75 static int iicbb_read(device_t
, char *, int, int *, int, int);
76 static int iicbb_reset(device_t
, u_char
, u_char
, u_char
*);
77 static int iicbb_transfer(device_t dev
, struct iic_msg
*msgs
, uint32_t nmsgs
);
79 static device_method_t iicbb_methods
[] = {
80 /* device interface */
81 DEVMETHOD(device_probe
, iicbb_probe
),
82 DEVMETHOD(device_attach
, iicbb_attach
),
83 DEVMETHOD(device_detach
, iicbb_detach
),
86 DEVMETHOD(bus_child_detached
, iicbb_child_detached
),
87 DEVMETHOD(bus_print_child
, iicbb_print_child
),
89 /* iicbus interface */
90 DEVMETHOD(iicbus_callback
, iicbb_callback
),
91 DEVMETHOD(iicbus_start
, iicbb_start
),
92 DEVMETHOD(iicbus_repeated_start
, iicbb_start
),
93 DEVMETHOD(iicbus_stop
, iicbb_stop
),
94 DEVMETHOD(iicbus_write
, iicbb_write
),
95 DEVMETHOD(iicbus_read
, iicbb_read
),
96 DEVMETHOD(iicbus_reset
, iicbb_reset
),
97 DEVMETHOD(iicbus_transfer
, iicbb_transfer
),
102 driver_t iicbb_driver
= {
105 sizeof(struct iicbb_softc
),
108 devclass_t iicbb_devclass
;
111 iicbb_probe(device_t dev
)
113 device_set_desc(dev
, "I2C bit-banging driver");
119 iicbb_attach(device_t dev
)
121 struct iicbb_softc
*sc
= (struct iicbb_softc
*)device_get_softc(dev
);
123 sc
->iicbus
= device_add_child(dev
, "iicbus", -1);
126 sc
->udelay
= 10; /* 10 uS default */
127 bus_generic_attach(dev
);
133 iicbb_detach(device_t dev
)
135 struct iicbb_softc
*sc
= (struct iicbb_softc
*)device_get_softc(dev
);
139 * We need to save child because the detach indirectly causes
140 * sc->iicbus to be zeroed. Since we added the device
141 * unconditionally in iicbb_attach, we need to make sure we
142 * delete it here. See iicbb_child_detached. We need that
143 * callback in case newbus detached our children w/o detaching
144 * us (say iicbus is a module and unloaded w/o iicbb being
148 bus_generic_detach(dev
);
150 device_delete_child(dev
, child
);
156 iicbb_child_detached( device_t dev
, device_t child
)
158 struct iicbb_softc
*sc
= (struct iicbb_softc
*)device_get_softc(dev
);
160 if (child
== sc
->iicbus
)
165 iicbb_print_child(device_t bus
, device_t dev
)
171 retval
+= bus_print_child_header(bus
, dev
);
172 /* retrieve the interface I2C address */
173 error
= IICBB_RESET(device_get_parent(bus
), IIC_FASTEST
, 0, &oldaddr
);
174 if (error
== IIC_ENOADDR
) {
175 retval
+= kprintf(" on %s master-only\n",
176 device_get_nameunit(bus
));
178 /* restore the address */
179 IICBB_RESET(device_get_parent(bus
), IIC_FASTEST
, oldaddr
, NULL
);
181 retval
+= kprintf(" on %s addr 0x%x\n",
182 device_get_nameunit(bus
), oldaddr
& 0xff);
188 #define I2C_SETSDA(sc,dev,val) do { \
189 IICBB_SETSDA(device_get_parent(dev), val); \
193 #define I2C_SETSCL(dev,val) do { \
194 iicbb_setscl(dev, val, 100); \
197 #define I2C_SET(sc,dev,ctrl,data) do { \
198 I2C_SETSCL(dev, ctrl); \
199 I2C_SETSDA(sc, dev, data); \
202 #define I2C_GETSDA(dev) (IICBB_GETSDA(device_get_parent(dev)))
204 #define I2C_GETSCL(dev) (IICBB_GETSCL(device_get_parent(dev)))
206 static int i2c_debug
= 0;
207 #define I2C_DEBUG(x) do { \
208 if (i2c_debug) (x); \
211 #define I2C_LOG(format,args...) do { \
212 kprintf(format, args); \
216 iicbb_setscl(device_t dev
, int val
, int timeout
)
218 struct iicbb_softc
*sc
= device_get_softc(dev
);
221 IICBB_SETSCL(device_get_parent(dev
), val
);
224 while (val
&& !I2C_GETSCL(dev
) && k
++ < timeout
) {
225 IICBB_SETSCL(device_get_parent(dev
), val
);
233 iicbb_one(device_t dev
, int timeout
)
235 struct iicbb_softc
*sc
= device_get_softc(dev
);
244 iicbb_zero(device_t dev
, int timeout
)
246 struct iicbb_softc
*sc
= device_get_softc(dev
);
255 * Waiting for ACKNOWLEDGE.
257 * When a chip is being addressed or has received data it will issue an
258 * ACKNOWLEDGE pulse. Therefore the MASTER must release the DATA line
259 * (set it to high level) and then release the CLOCK line.
260 * Now it must wait for the SLAVE to pull the DATA line low.
261 * Actually on the bus this looks like a START condition so nothing happens
262 * because of the fact that the IC's that have not been addressed are doing
265 * When the SLAVE has pulled this line low the MASTER will take the CLOCK
266 * line low and then the SLAVE will release the SDA (data) line.
269 iicbb_ack(device_t dev
, int timeout
)
271 struct iicbb_softc
*sc
= device_get_softc(dev
);
278 noack
= I2C_GETSDA(dev
);
283 } while (k
< timeout
);
286 I2C_DEBUG(kprintf("%c ",noack
?'-':'+'));
292 iicbb_sendbyte(device_t dev
, u_char data
, int timeout
)
296 for (i
=7; i
>=0; i
--) {
298 iicbb_one(dev
, timeout
);
300 iicbb_zero(dev
, timeout
);
303 I2C_DEBUG(kprintf("w%02x",(int)data
));
308 iicbb_readbyte(device_t dev
, int last
, int timeout
)
310 struct iicbb_softc
*sc
= device_get_softc(dev
);
312 unsigned char data
=0;
323 iicbb_one(dev
, timeout
);
325 iicbb_zero(dev
, timeout
);
327 I2C_DEBUG(kprintf("r%02x%c ",(int)data
,last
?'-':'+'));
332 iicbb_callback(device_t dev
, int index
, caddr_t data
)
334 return (IICBB_CALLBACK(device_get_parent(dev
), index
, data
));
338 iicbb_reset(device_t dev
, u_char speed
, u_char addr
, u_char
*oldaddr
)
340 return (IICBB_RESET(device_get_parent(dev
), speed
, addr
, oldaddr
));
344 iicbb_start(device_t dev
, u_char slave
, int timeout
)
346 struct iicbb_softc
*sc
= device_get_softc(dev
);
349 I2C_DEBUG(kprintf("<"));
356 iicbb_sendbyte(dev
, slave
, timeout
);
359 if (iicbb_ack(dev
, timeout
)) {
372 iicbb_stop(device_t dev
)
374 struct iicbb_softc
*sc
= device_get_softc(dev
);
379 I2C_DEBUG(kprintf(">"));
380 I2C_DEBUG(kprintf("\n"));
385 iicbb_write(device_t dev
, const char *buf
, int len
, int *sent
, int timeout
)
387 int bytes
, error
= 0;
392 iicbb_sendbyte(dev
,(u_char
)*buf
++, timeout
);
395 if (iicbb_ack(dev
, timeout
)) {
409 iicbb_read(device_t dev
, char * buf
, int len
, int *read
, int last
, int delay
)
415 /* XXX should insert delay here */
416 *buf
++ = (char)iicbb_readbyte(dev
, (len
== 1) ? last
: 0, delay
);
427 iicbb_transfer(device_t dev
, struct iic_msg
*msgs
, uint32_t nmsgs
)
431 error
= IICBB_PRE_XFER(device_get_parent(dev
));
435 error
= iicbus_transfer_gen(dev
, msgs
, nmsgs
);
437 IICBB_POST_XFER(device_get_parent(dev
));
441 DRIVER_MODULE(iicbb
, bti2c
, iicbb_driver
, iicbb_devclass
, NULL
, NULL
);
442 DRIVER_MODULE(iicbb
, cxm_iic
, iicbb_driver
, iicbb_devclass
, NULL
, NULL
);
443 DRIVER_MODULE(iicbb
, intel_iic
, iicbb_driver
, iicbb_devclass
, NULL
, NULL
);
444 DRIVER_MODULE(iicbb
, lpbb
, iicbb_driver
, iicbb_devclass
, NULL
, NULL
);
445 DRIVER_MODULE(iicbb
, viapm
, iicbb_driver
, iicbb_devclass
, NULL
, NULL
);
447 MODULE_DEPEND(iicbb
, iicbus
, IICBUS_MINVER
, IICBUS_PREFVER
, IICBUS_MAXVER
);
448 MODULE_VERSION(iicbb
, IICBB_MODVER
);