Module Name: src
Committed By: mbalmer
Date: Sun Aug 9 08:18:01 UTC 2009
Modified Files:
src/sys/dev/gpio: files.gpio
Added Files:
src/sys/dev/gpio: gpioiic.c
Log Message:
gpioiic(4), a driver to do use GPIO pins in bit-banging mode to form an I2C
bus. Ported from OpenBSD.
To generate a diff of this commit:
cvs rdiff -u -r1.6 -r1.7 src/sys/dev/gpio/files.gpio
cvs rdiff -u -r0 -r1.1 src/sys/dev/gpio/gpioiic.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/gpio/files.gpio
diff -u src/sys/dev/gpio/files.gpio:1.6 src/sys/dev/gpio/files.gpio:1.7
--- src/sys/dev/gpio/files.gpio:1.6 Mon Jul 27 17:40:57 2009
+++ src/sys/dev/gpio/files.gpio Sun Aug 9 08:18:00 2009
@@ -1,4 +1,4 @@
-# $NetBSD: files.gpio,v 1.6 2009/07/27 17:40:57 mbalmer Exp $
+# $NetBSD: files.gpio,v 1.7 2009/08/09 08:18:00 mbalmer Exp $
define gpio {[offset = -1], [mask = 0]}
@@ -10,6 +10,11 @@
defpseudodev gpiosim: gpiobus
file dev/gpio/gpiosim.c gpiosim
+# I2C bus bit-banging
+device gpioiic: i2cbus, i2c_bitbang
+attach gpioiic at gpio
+file dev/gpio/gpioiic.c gpioiic
+
# 1-Wire bus bit-banging
device gpioow: onewirebus, onewire_bitbang
attach gpioow at gpio
Added files:
Index: src/sys/dev/gpio/gpioiic.c
diff -u /dev/null src/sys/dev/gpio/gpioiic.c:1.1
--- /dev/null Sun Aug 9 08:18:01 2009
+++ src/sys/dev/gpio/gpioiic.c Sun Aug 9 08:18:00 2009
@@ -0,0 +1,316 @@
+/* $NetBSD: gpioiic.c,v 1.1 2009/08/09 08:18:00 mbalmer Exp $ */
+/* $OpenBSD: gpioiic.c,v 1.8 2008/11/24 12:12:12 mbalmer Exp $ */
+
+/*
+ * Copyright (c) 2006 Alexander Yurchenko <[email protected]>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: gpioiic.c,v 1.1 2009/08/09 08:18:00 mbalmer Exp $");
+
+/*
+ * I2C bus bit-banging through GPIO pins.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/gpio.h>
+#include <sys/rwlock.h>
+
+#include <dev/gpio/gpiovar.h>
+
+#include <dev/i2c/i2cvar.h>
+#include <dev/i2c/i2c_bitbang.h>
+
+#define GPIOIIC_PIN_SDA 0
+#define GPIOIIC_PIN_SCL 1
+#define GPIOIIC_NPINS 2
+
+#define GPIOIIC_SDA 0x01
+#define GPIOIIC_SCL 0x02
+
+struct gpioiic_softc {
+ void * sc_gpio;
+ struct gpio_pinmap sc_map;
+ int _map[GPIOIIC_NPINS];
+
+ struct i2c_controller sc_i2c_tag;
+ device_t sc_i2c_dev;
+ krwlock_t sc_i2c_lock;
+
+ int sc_sda;
+ int sc_scl;
+};
+
+int gpioiic_match(device_t, cfdata_t, void *);
+void gpioiic_attach(device_t, device_t, void *);
+int gpioiic_detach(device_t, int);
+int gpioiic_activate(device_t, enum devact);
+
+int gpioiic_i2c_acquire_bus(void *, int);
+void gpioiic_i2c_release_bus(void *, int);
+int gpioiic_i2c_send_start(void *, int);
+int gpioiic_i2c_send_stop(void *, int);
+int gpioiic_i2c_initiate_xfer(void *, i2c_addr_t, int);
+int gpioiic_i2c_read_byte(void *, u_int8_t *, int);
+int gpioiic_i2c_write_byte(void *, u_int8_t, int);
+
+void gpioiic_bb_set_bits(void *, u_int32_t);
+void gpioiic_bb_set_dir(void *, u_int32_t);
+u_int32_t gpioiic_bb_read_bits(void *);
+
+CFATTACH_DECL_NEW(gpioiic, sizeof(struct gpioiic_softc),
+ gpioiic_match, gpioiic_attach, gpioiic_detach, gpioiic_activate);
+
+extern struct cfdriver gpioiic_cd;
+
+static const struct i2c_bitbang_ops gpioiic_bbops = {
+ gpioiic_bb_set_bits,
+ gpioiic_bb_set_dir,
+ gpioiic_bb_read_bits,
+ { GPIOIIC_SDA, GPIOIIC_SCL, GPIOIIC_SDA, 0 }
+};
+
+int
+gpioiic_match(device_t parent, cfdata_t cf, void *aux)
+{
+ struct gpio_attach_args *ga = aux;
+
+ if (strcmp(ga->ga_dvname, cf->cf_name))
+ return 0;
+
+ if (ga->ga_offset == -1)
+ return 0;
+
+ /* Check that we have enough pins */
+ if (gpio_npins(ga->ga_mask) != GPIOIIC_NPINS) {
+ aprint_debug("%s: invalid pin mask 0x%02x\n", cf->cf_name,
+ ga->ga_mask);
+ return 0;
+ }
+ return 1;
+}
+
+void
+gpioiic_attach(struct device *parent, struct device *self, void *aux)
+{
+ struct gpioiic_softc *sc = device_private(self);
+ struct gpio_attach_args *ga = aux;
+ struct i2cbus_attach_args iba;
+ int caps;
+
+ /* Map pins */
+ sc->sc_gpio = ga->ga_gpio;
+ sc->sc_map.pm_map = sc->_map;
+ if (gpio_pin_map(sc->sc_gpio, ga->ga_offset, ga->ga_mask,
+ &sc->sc_map)) {
+ aprint_error(": can't map pins\n");
+ return;
+ }
+
+ /* Configure SDA pin */
+ caps = gpio_pin_caps(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SDA);
+ if (!(caps & GPIO_PIN_OUTPUT)) {
+ aprint_error(": SDA pin is unable to drive output\n");
+ goto fail;
+ }
+ if (!(caps & GPIO_PIN_INPUT)) {
+ aprint_error(": SDA pin is unable to read input\n");
+ goto fail;
+ }
+ aprint_normal(": SDA[%d]", sc->sc_map.pm_map[GPIOIIC_PIN_SDA]);
+ sc->sc_sda = GPIO_PIN_OUTPUT;
+ if (caps & GPIO_PIN_OPENDRAIN) {
+ aprint_normal(" open-drain");
+ sc->sc_sda |= GPIO_PIN_OPENDRAIN;
+ } else if ((caps & GPIO_PIN_PUSHPULL) && (caps & GPIO_PIN_TRISTATE)) {
+ aprint_normal(" push-pull tri-state");
+ sc->sc_sda |= GPIO_PIN_PUSHPULL;
+ }
+ if (caps & GPIO_PIN_PULLUP) {
+ aprint_normal(" pull-up");
+ sc->sc_sda |= GPIO_PIN_PULLUP;
+ }
+ gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SDA, sc->sc_sda);
+
+ /* Configure SCL pin */
+ caps = gpio_pin_caps(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SCL);
+ if (!(caps & GPIO_PIN_OUTPUT)) {
+ aprint_error(": SCL pin is unable to drive output\n");
+ goto fail;
+ }
+ aprint_normal(", SCL[%d]", sc->sc_map.pm_map[GPIOIIC_PIN_SCL]);
+ sc->sc_scl = GPIO_PIN_OUTPUT;
+ if (caps & GPIO_PIN_OPENDRAIN) {
+ aprint_normal(" open-drain");
+ sc->sc_scl |= GPIO_PIN_OPENDRAIN;
+ if (caps & GPIO_PIN_PULLUP) {
+ aprint_normal(" pull-up");
+ sc->sc_scl |= GPIO_PIN_PULLUP;
+ }
+ } else if (caps & GPIO_PIN_PUSHPULL) {
+ aprint_normal(" push-pull");
+ sc->sc_scl |= GPIO_PIN_PUSHPULL;
+ }
+ gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SCL, sc->sc_scl);
+
+ aprint_normal("\n");
+
+ /* Attach I2C bus */
+ rw_init(&sc->sc_i2c_lock);
+ sc->sc_i2c_tag.ic_cookie = sc;
+ sc->sc_i2c_tag.ic_acquire_bus = gpioiic_i2c_acquire_bus;
+ sc->sc_i2c_tag.ic_release_bus = gpioiic_i2c_release_bus;
+ sc->sc_i2c_tag.ic_send_start = gpioiic_i2c_send_start;
+ sc->sc_i2c_tag.ic_send_stop = gpioiic_i2c_send_stop;
+ sc->sc_i2c_tag.ic_initiate_xfer = gpioiic_i2c_initiate_xfer;
+ sc->sc_i2c_tag.ic_read_byte = gpioiic_i2c_read_byte;
+ sc->sc_i2c_tag.ic_write_byte = gpioiic_i2c_write_byte;
+ sc->sc_i2c_tag.ic_exec = NULL;
+
+ memset(&iba, 0, sizeof(iba));
+ iba.iba_type = I2C_TYPE_SMBUS;
+ iba.iba_tag = &sc->sc_i2c_tag;
+ sc->sc_i2c_dev = config_found(self, &iba, iicbus_print);
+
+ if (!pmf_device_register(self, NULL, NULL))
+ aprint_error("%s: could not establish power handler\n",
+ device_xname(self));
+ return;
+
+fail:
+ gpio_pin_unmap(sc->sc_gpio, &sc->sc_map);
+}
+
+int
+gpioiic_detach(struct device *self, int flags)
+{
+ struct gpioiic_softc *sc = device_private(self);
+ int rv = 0;
+
+ if (sc->sc_i2c_dev != NULL)
+ rv = config_detach(sc->sc_i2c_dev, flags);
+
+ if (!rv) {
+ gpio_pin_unmap(sc->sc_gpio, &sc->sc_map);
+ pmf_device_deregister(self);
+ }
+ return rv;
+}
+
+int
+gpioiic_activate(device_t self, enum devact act)
+{
+ int rv = 0;
+
+ switch (act) {
+ case DVACT_ACTIVATE:
+ return EOPNOTSUPP;
+ case DVACT_DEACTIVATE:
+ break;
+ }
+ return rv;
+}
+
+int
+gpioiic_i2c_acquire_bus(void *cookie, int flags)
+{
+ struct gpioiic_softc *sc = cookie;
+
+ if (flags & I2C_F_POLL)
+ return 0;
+
+ rw_enter(&sc->sc_i2c_lock, RW_WRITER);
+ return 1;
+}
+
+void
+gpioiic_i2c_release_bus(void *cookie, int flags)
+{
+ struct gpioiic_softc *sc = cookie;
+
+ if (flags & I2C_F_POLL)
+ return;
+
+ rw_exit(&sc->sc_i2c_lock);
+}
+
+int
+gpioiic_i2c_send_start(void *cookie, int flags)
+{
+ return i2c_bitbang_send_start(cookie, flags, &gpioiic_bbops);
+}
+
+int
+gpioiic_i2c_send_stop(void *cookie, int flags)
+{
+ return i2c_bitbang_send_stop(cookie, flags, &gpioiic_bbops);
+}
+
+int
+gpioiic_i2c_initiate_xfer(void *cookie, i2c_addr_t addr, int flags)
+{
+ return i2c_bitbang_initiate_xfer(cookie, addr, flags, &gpioiic_bbops);
+}
+
+int
+gpioiic_i2c_read_byte(void *cookie, u_int8_t *bytep, int flags)
+{
+ return i2c_bitbang_read_byte(cookie, bytep, flags, &gpioiic_bbops);
+}
+
+int
+gpioiic_i2c_write_byte(void *cookie, u_int8_t byte, int flags)
+{
+ return i2c_bitbang_write_byte(cookie, byte, flags, &gpioiic_bbops);
+}
+
+void
+gpioiic_bb_set_bits(void *cookie, u_int32_t bits)
+{
+ struct gpioiic_softc *sc = cookie;
+
+ gpio_pin_write(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SDA,
+ bits & GPIOIIC_SDA ? GPIO_PIN_HIGH : GPIO_PIN_LOW);
+ gpio_pin_write(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SCL,
+ bits & GPIOIIC_SCL ? GPIO_PIN_HIGH : GPIO_PIN_LOW);
+}
+
+void
+gpioiic_bb_set_dir(void *cookie, u_int32_t bits)
+{
+ struct gpioiic_softc *sc = cookie;
+ int sda = sc->sc_sda;
+
+ sda &= ~(GPIO_PIN_INPUT | GPIO_PIN_OUTPUT | GPIO_PIN_TRISTATE);
+ sda |= (bits & GPIOIIC_SDA ? GPIO_PIN_OUTPUT : GPIO_PIN_INPUT);
+ if ((sda & GPIO_PIN_PUSHPULL) && !(bits & GPIOIIC_SDA))
+ sda |= GPIO_PIN_TRISTATE;
+ if (sc->sc_sda != sda) {
+ sc->sc_sda = sda;
+ gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SDA,
+ sc->sc_sda);
+ }
+}
+
+u_int32_t
+gpioiic_bb_read_bits(void *cookie)
+{
+ struct gpioiic_softc *sc = cookie;
+
+ return gpio_pin_read(sc->sc_gpio, &sc->sc_map,
+ GPIOIIC_PIN_SDA) == GPIO_PIN_HIGH ? GPIOIIC_SDA : 0;
+}
