Support for I2C bus bit-banging through the GPIO pins.

Now Soekris people can enjoy our fancy I2C stuff, too:

nsclpcsio0 at isa0 port 0x2e/2: NSC PC87366 rev 9: GPIO VLM TMS
gpio1 at nsclpcsio0: 29 pins
gpioiic0 at gpio1 pins 17 19
iic0 at gpioiic0
maxds0 at iic0 addr 0x48: ds1624, starting
maxds1 at iic0 addr 0x49: ds1624, starting

1 files changed, 213 insertions, 0 deletions

diff --git a/sys/dev/gpio/gpioiic.c b/sys/dev/gpio/gpioiic.c
new file mode 100644
index 00000000000..a6ce1a4c783
--- /dev/null
+++ b/sys/dev/gpio/gpioiic.c
@@ -0,0 +1,213 @@
+/*	$OpenBSD: gpioiic.c,v 1.1 2006/01/14 00:14:21 grange Exp $	*/
+
+/*
+ * Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org>
+ *
+ * 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.
+ */
+
+/*
+ * I2C bus bit-banging through GPIO pins.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/gpio.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 {
+	struct device		sc_dev;
+
+	void *			sc_gpio;
+	struct gpio_pinmap	sc_map;
+	int			__map[GPIOIIC_NPINS];
+
+	struct i2c_controller	sc_i2c_tag;
+	struct lock		sc_i2c_lock;
+};
+
+int		gpioiic_match(struct device *, void *, void *);
+void		gpioiic_attach(struct device *, struct device *, void *);
+
+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 *);
+
+struct cfattach gpioiic_ca = {
+	sizeof(struct gpioiic_softc),
+	gpioiic_match,
+	gpioiic_attach
+};
+
+struct cfdriver gpioiic_cd = {
+	NULL, "gpioiic", DV_DULL
+};
+
+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(struct device *parent, void *match, void *aux)
+{
+	struct cfdata *cf = match;
+
+	if (strcmp(cf->cf_driver->cd_name, "gpioiic") == 0)
+		return (1);
+
+	return (0);
+}
+
+void
+gpioiic_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct gpioiic_softc *sc = (struct gpioiic_softc *)self;
+	struct gpio_attach_args *ga = aux;
+	struct i2cbus_attach_args iba;
+
+	if (gpio_npins(ga->ga_mask) != GPIOIIC_NPINS) {
+		printf(": invalid pin mask\n");
+		return;
+	}
+
+	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)) {
+		printf(": can't map pins\n");
+		return;
+	}
+
+	gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SDA,
+	    GPIO_PIN_OUTPUT | GPIO_PIN_OPENDRAIN | GPIO_PIN_PULLUP);
+	gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SCL,
+	    GPIO_PIN_OUTPUT | GPIO_PIN_OPENDRAIN | GPIO_PIN_PULLUP);
+
+	printf("\n");
+
+	/* Attach I2C bus */
+	lockinit(&sc->sc_i2c_lock, PRIBIO | PCATCH, "iiclk", 0, 0);
+	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;
+
+	bzero(&iba, sizeof(iba));
+	iba.iba_name = "iic";
+	iba.iba_tag = &sc->sc_i2c_tag;
+	config_found(self, &iba, iicbus_print);
+}
+
+int
+gpioiic_i2c_acquire_bus(void *cookie, int flags)
+{
+	struct gpioiic_softc *sc = cookie;
+
+	if (cold || (flags & I2C_F_POLL))
+		return (0);
+
+	return (lockmgr(&sc->sc_i2c_lock, LK_EXCLUSIVE, NULL));
+}
+
+void
+gpioiic_i2c_release_bus(void *cookie, int flags)
+{
+	struct gpioiic_softc *sc = cookie;
+
+	if (cold || (flags & I2C_F_POLL))
+		return;
+
+	lockmgr(&sc->sc_i2c_lock, LK_RELEASE, NULL);
+}
+
+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)
+{
+}
+
+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);
+}