xref: /src/sys/dev/i2c/bmx280thpi2c.c

/*	$NetBSD: bmx280thpi2c.c,v 1.4 2025/09/13 16:16:40 thorpej Exp $	*/

/*
 * Copyright (c) 2022 Brad Spencer <brad (at) anduin.eldar.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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: bmx280thpi2c.c,v 1.4 2025/09/13 16:16:40 thorpej Exp $");

/*
 * I2C driver for the Bosch BMP280 / BME280 sensor.
 * Uses the common bmx280thp driver to do the real work.
*/

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/module.h>
#include <sys/conf.h>
#include <sys/sysctl.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/pool.h>
#include <sys/kmem.h>

#include <dev/sysmon/sysmonvar.h>
#include <dev/i2c/i2cvar.h>
#include <dev/spi/spivar.h>
#include <dev/ic/bmx280reg.h>
#include <dev/ic/bmx280var.h>

struct bmx280_i2c_softc {
	struct bmx280_sc	sc_bmx280;
	i2c_tag_t		sc_tag;
	i2c_addr_t		sc_addr;
};

#define	BMX280_TO_I2C(sc)	\
	container_of((sc), struct bmx280_i2c_softc, sc_bmx280)

static int 	bmx280thpi2c_poke(i2c_tag_t, i2c_addr_t, bool);
static int 	bmx280thpi2c_match(device_t, cfdata_t, void *);
static void 	bmx280thpi2c_attach(device_t, device_t, void *);
static int 	bmx280thpi2c_detach(device_t, int);

CFATTACH_DECL_NEW(bmx280thpi2c, sizeof(struct bmx280_sc),
    bmx280thpi2c_match, bmx280thpi2c_attach, bmx280thpi2c_detach, NULL);

/* For the BMX280, a read consists of writing on the I2C bus
 * a I2C START, I2C SLAVE address, then the starting register.
 * If that works, then following will be another I2C START,
 * I2C SLAVE address, followed by as many I2C reads that is
 * desired and then a I2C STOP
 */

static int
bmx280thpi2c_read_register_direct(i2c_tag_t tag, i2c_addr_t addr, uint8_t reg,
    uint8_t *buf, size_t blen)
{
	int error;

	error = iic_exec(tag,I2C_OP_WRITE,addr,&reg,1,NULL,0,0);

	if (error == 0) {
		error = iic_exec(tag,I2C_OP_READ_WITH_STOP,addr,NULL,0,
		    buf,blen,0);
	}

	return error;
}

static int
bmx280thpi2c_read_register(struct bmx280_sc *sc, uint8_t reg,
    uint8_t *buf, size_t blen)
{
	struct bmx280_i2c_softc *isc = BMX280_TO_I2C(sc);
	int error;

	KASSERT(blen > 0);

	error = bmx280thpi2c_read_register_direct(isc->sc_tag, isc->sc_addr,
	    reg, buf, blen);

	return error;
}

/* For the BMX280, a write consists of sending a I2C START, I2C SLAVE
 * address and then pairs of registers and data until a I2C STOP is
 * sent.
 */

static int
bmx280thpi2c_write_register(struct bmx280_sc *sc, uint8_t *buf, size_t blen)
{
	struct bmx280_i2c_softc *isc = BMX280_TO_I2C(sc);
	int error;

	KASSERT(blen > 0);
	/* XXX - there should be a KASSERT for blen at least
	   being an even number */

	error = iic_exec(isc->sc_tag,I2C_OP_WRITE_WITH_STOP,isc->sc_addr,NULL,0,
	    buf,blen,0);

	return error;
}

static int
bmx280thpi2c_acquire_bus(struct bmx280_sc *sc)
{
	struct bmx280_i2c_softc *isc = BMX280_TO_I2C(sc);

	return(iic_acquire_bus(isc->sc_tag, 0));
}

static void
bmx280thpi2c_release_bus(struct bmx280_sc *sc)
{
	struct bmx280_i2c_softc *isc = BMX280_TO_I2C(sc);

	iic_release_bus(isc->sc_tag, 0);
}

static const struct bmx280_accessfuncs bmx280_i2c_accessfuncs = {
	.acquire_bus	=	bmx280thpi2c_acquire_bus,
	.release_bus	=	bmx280thpi2c_release_bus,
	.read_reg	=	bmx280thpi2c_read_register,
	.write_reg	=	bmx280thpi2c_write_register,
};

static int
bmx280thpi2c_poke(i2c_tag_t tag, i2c_addr_t addr, bool matchdebug)
{
	uint8_t reg = BMX280_REGISTER_ID;
	uint8_t buf[1];
	int error;

	error = bmx280thpi2c_read_register_direct(tag, addr, reg, buf, 1);
	if (matchdebug) {
		printf("poke X 1: %d\n", error);
	}
	return error;
}

static int
bmx280thpi2c_match(device_t parent, cfdata_t cf, void *aux)
{
	struct i2c_attach_args *ia = aux;
	int error, match_result;
	const bool matchdebug = false;

	if (iic_use_direct_match(ia, cf, bmx280_compat_data, &match_result)) {
		return match_result;
	}

	/* indirect config - check for configured address */
	if (ia->ia_addr != BMX280_TYPICAL_ADDR_1 &&
	    ia->ia_addr != BMX280_TYPICAL_ADDR_2)
		return 0;

	/*
	 * Check to see if something is really at this i2c address. This will
	 * keep phantom devices from appearing
	 */
	if (iic_acquire_bus(ia->ia_tag, 0) != 0) {
		if (matchdebug)
			printf("in match acquire bus failed\n");
		return 0;
	}

	error = bmx280thpi2c_poke(ia->ia_tag, ia->ia_addr, matchdebug);
	iic_release_bus(ia->ia_tag, 0);

	return error == 0 ? I2C_MATCH_ADDRESS_AND_PROBE : 0;
}

static void
bmx280thpi2c_attach(device_t parent, device_t self, void *aux)
{
	struct bmx280_i2c_softc *isc = device_private(self);
	struct bmx280_sc *sc = &isc->sc_bmx280;
	struct i2c_attach_args *ia = aux;

	sc->sc_dev = self;
	sc->sc_funcs = &bmx280_i2c_accessfuncs;

	isc->sc_tag = ia->ia_tag;
	isc->sc_addr = ia->ia_addr;

	bmx280_attach(sc);
}

static int
bmx280thpi2c_detach(device_t self, int flags)
{
	struct bmx280_i2c_softc *isc = device_private(self);

	return bmx280_detach(&isc->sc_bmx280, flags);
}

MODULE(MODULE_CLASS_DRIVER, bmx280thpi2c, "iic,bmx280thp");

#ifdef _MODULE
/* Like other drivers, we do this because the bmx280 common
 * driver has the definitions already.
 */
#undef  CFDRIVER_DECL
#define CFDRIVER_DECL(name, class, attr)
#include "ioconf.c"
#endif

static int
bmx280thpi2c_modcmd(modcmd_t cmd, void *opaque)
{

	switch (cmd) {
	case MODULE_CMD_INIT:
#ifdef _MODULE
		return config_init_component(cfdriver_ioconf_bmx280thpi2c,
		    cfattach_ioconf_bmx280thpi2c, cfdata_ioconf_bmx280thpi2c);
#else
		return 0;
#endif
	case MODULE_CMD_FINI:
#ifdef _MODULE
		return config_fini_component(cfdriver_ioconf_bmx280thpi2c,
		      cfattach_ioconf_bmx280thpi2c, cfdata_ioconf_bmx280thpi2c);
#else
		return 0;
#endif
	default:
		return ENOTTY;
	}
}