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/* $OpenBSD: gpioiic.c,v 1.2 2006/01/14 12:54:50 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 sc_sda;
int sc_scl;
};
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;
int caps;
/* Check that we have enough pins */
if (gpio_npins(ga->ga_mask) != GPIOIIC_NPINS) {
printf(": invalid pin mask\n");
return;
}
/* 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)) {
printf(": 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)) {
printf(": SDA pin is unable to drive output\n");
goto fail;
}
printf(": SDA[%d]", sc->sc_map.pm_map[GPIOIIC_PIN_SDA]);
sc->sc_sda = GPIO_PIN_OUTPUT;
if (caps & GPIO_PIN_OPENDRAIN) {
printf(" open-drain");
sc->sc_sda |= GPIO_PIN_OPENDRAIN;
if (caps & GPIO_PIN_PULLUP) {
printf(" 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)) {
printf(": SCL pin is unable to drive output\n");
goto fail;
}
printf(", SCL[%d]", sc->sc_map.pm_map[GPIOIIC_PIN_SCL]);
sc->sc_scl = GPIO_PIN_OUTPUT;
if (caps & GPIO_PIN_OPENDRAIN) {
printf(" open-drain");
sc->sc_scl |= GPIO_PIN_OPENDRAIN;
if (caps & GPIO_PIN_PULLUP) {
printf(" pull-up");
sc->sc_scl |= GPIO_PIN_PULLUP;
}
} else if (caps & GPIO_PIN_PUSHPULL) {
printf(" push-pull");
sc->sc_scl |= GPIO_PIN_PUSHPULL;
}
gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOIIC_PIN_SCL, sc->sc_scl);
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);
return;
fail:
gpio_pin_unmap(sc->sc_gpio, &sc->sc_map);
}
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)
{
struct gpioiic_softc *sc = cookie;
if (!(sc->sc_sda & GPIO_PIN_OPENDRAIN)) {
sc->sc_sda &= ~(GPIO_PIN_INPUT | GPIO_PIN_OUTPUT);
sc->sc_sda |= (bits & GPIOIIC_SDA ? GPIO_PIN_OUTPUT :
GPIO_PIN_INPUT);
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);
}
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