tca6416.c

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/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2020 Alstom Group.
 * Copyright (c) 2020 Semihalf.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
 
/*
 * Driver for TI TCA6416 I2C GPIO expander module.
 *
 * This driver only supports basic functionality
 * (interrupt handling and polarity inversion were omitted).
 */
 
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
 
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/gpio.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
 
#include <machine/bus.h>
 
#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
 
#include <dev/iicbus/iicbus.h>
#include <dev/iicbus/iiconf.h>
 
#include <dev/gpio/gpiobusvar.h>
 
#include "gpio_if.h"
 
/* Base addresses of registers. LSB omitted. */
#define IN_PORT_REG             0x00
#define OUT_PORT_REG            0x02
#define POLARITY_INV_REG        0x04
#define CONF_REG                0x06
 
#define NUM_PINS        16
#define PINS_PER_REG    8
#define PIN_CAPS                                \
        (GPIO_PIN_OUTPUT | GPIO_PIN_INPUT       \
        | GPIO_PIN_PUSHPULL | GPIO_PIN_INVIN)
 
#ifdef DEBUG
#define dbg_dev_printf(dev, fmt, args...)       \
        device_printf(dev, fmt, ##args)
#else
#define dbg_dev_printf(dev, fmt, args...)
#endif
 
#define TCA6416_BIT_FROM_PIN(pin)       (pin % PINS_PER_REG)
#define TCA6416_REG_ADDR(pin, baseaddr) (baseaddr | (pin / PINS_PER_REG))
 
struct tca6416_softc {
        device_t        dev;
        device_t        busdev;
        struct mtx      mtx;
        uint32_t        addr;
};
 
static int tca6416_read(device_t, uint8_t, uint8_t*);
static int tca6416_write(device_t, uint8_t, uint8_t);
static int tca6416_probe(device_t);
static int tca6416_attach(device_t);
static int tca6416_detach(device_t);
static device_t tca6416_get_bus(device_t);
static int tca6416_pin_max(device_t, int*);
static int tca6416_pin_getcaps(device_t, uint32_t, uint32_t*);
static int tca6416_pin_getflags(device_t, uint32_t, uint32_t*);
static int tca6416_pin_setflags(device_t, uint32_t, uint32_t);
static int tca6416_pin_getname(device_t, uint32_t, char*);
static int tca6416_pin_get(device_t, uint32_t, unsigned int*);
static int tca6416_pin_set(device_t, uint32_t, unsigned int);
static int tca6416_pin_toggle(device_t, uint32_t);
#ifdef DEBUG
static void tca6416_regdump_setup(device_t dev);
static int tca6416_regdump_sysctl(SYSCTL_HANDLER_ARGS);
#endif
 
static device_method_t tca6416_methods[] = {
        DEVMETHOD(device_probe,         tca6416_probe),
        DEVMETHOD(device_attach,        tca6416_attach),
        DEVMETHOD(device_detach,        tca6416_detach),
 
        /* GPIO methods */
        DEVMETHOD(gpio_get_bus,         tca6416_get_bus),
        DEVMETHOD(gpio_pin_max,         tca6416_pin_max),
        DEVMETHOD(gpio_pin_getcaps,     tca6416_pin_getcaps),
        DEVMETHOD(gpio_pin_getflags,    tca6416_pin_getflags),
        DEVMETHOD(gpio_pin_setflags,    tca6416_pin_setflags),
        DEVMETHOD(gpio_pin_getname,     tca6416_pin_getname),
        DEVMETHOD(gpio_pin_get,         tca6416_pin_get),
        DEVMETHOD(gpio_pin_set,         tca6416_pin_set),
        DEVMETHOD(gpio_pin_toggle,      tca6416_pin_toggle),
 
        DEVMETHOD_END
};
 
static driver_t tca6416_driver = {
        "gpio",
        tca6416_methods,
        sizeof(struct tca6416_softc)
};
 
static devclass_t tca6416_devclass;
 
DRIVER_MODULE(tca6416, iicbus, tca6416_driver, tca6416_devclass, 0, 0);
MODULE_VERSION(tca6416, 1);
 
static struct ofw_compat_data compat_data[] = {
        {"ti,tca6416",  1},
        {0,0}
};
 
static int
tca6416_read(device_t dev, uint8_t reg, uint8_t *data)
{
        struct iic_msg msgs[2];
        struct tca6416_softc *sc;
        int error;
 
        sc = device_get_softc(dev);
        if (data == NULL)
                return (EINVAL);
 
        msgs[0].slave = sc->addr;
        msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
        msgs[0].len = 1;
        msgs[0].buf = &reg;
 
        msgs[1].slave = sc->addr;
        msgs[1].flags = IIC_M_RD;
        msgs[1].len = 1;
        msgs[1].buf = data;
 
        error = iicbus_transfer_excl(dev, msgs, 2, IIC_WAIT);
        return (iic2errno(error));
}
 
static int
tca6416_write(device_t dev, uint8_t reg, uint8_t val)
{
        struct iic_msg msg;
        struct tca6416_softc *sc;
        int error;
        uint8_t buffer[2] = {reg, val};
 
        sc = device_get_softc(dev);
 
        msg.slave = sc->addr;
        msg.flags = IIC_M_WR;
        msg.len = 2;
        msg.buf = buffer;
 
        error = iicbus_transfer_excl(dev, &msg, 1, IIC_WAIT);
        return (iic2errno(error));
}
 
static int
tca6416_probe(device_t dev)
{
 
        if (!ofw_bus_status_okay(dev))
                return (ENXIO);
 
        if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
                return (ENXIO);
 
        device_set_desc(dev, "TCA6416 I/O expander");
        return (BUS_PROBE_DEFAULT);
}
 
static int
tca6416_attach(device_t dev)
{
        struct tca6416_softc *sc;
 
        sc = device_get_softc(dev);
        sc->dev = dev;
        sc->addr = iicbus_get_addr(dev);
 
        mtx_init(&sc->mtx, "tca6416 gpio", "gpio", MTX_DEF);
 
        sc->busdev = gpiobus_attach_bus(dev);
        if (sc->busdev == NULL) {
                device_printf(dev, "Could not create busdev child\n");
                return (ENXIO);
        }
 
#ifdef DEBUG
        tca6416_regdump_setup(dev);
#endif
 
        return (0);
}
 
static int
tca6416_detach(device_t dev)
{
        struct tca6416_softc *sc;
 
        sc = device_get_softc(dev);
 
        if (sc->busdev != NULL)
                gpiobus_detach_bus(sc->busdev);
 
        mtx_destroy(&sc->mtx);
 
        return (0);
}
 
static device_t
tca6416_get_bus(device_t dev)
{
        struct tca6416_softc *sc;
 
        sc = device_get_softc(dev);
 
        return (sc->busdev);
}
 
static int
tca6416_pin_max(device_t dev __unused, int *maxpin)
{
 
        if (maxpin == NULL)
                return (EINVAL);
 
        *maxpin = NUM_PINS - 1;
        return (0);
}
 
static int
tca6416_pin_getcaps(device_t dev, uint32_t pin, uint32_t *caps)
{
 
        if (pin >= NUM_PINS || caps == NULL)
                return (EINVAL);
 
        *caps = PIN_CAPS;
        return (0);
}
 
static int
tca6416_pin_getflags(device_t dev, uint32_t pin, uint32_t *pflags)
{
        struct tca6416_softc *sc;
        int error;
        uint8_t reg_addr, reg_bit, val;
 
        sc = device_get_softc(dev);
 
        if (pin >= NUM_PINS || pflags == NULL)
                return (EINVAL);
 
        reg_addr = TCA6416_REG_ADDR(pin, CONF_REG);
        reg_bit = TCA6416_BIT_FROM_PIN(pin);
 
        error = tca6416_read(dev, reg_addr, &val);
        if (error != 0)
                return (error);
 
        *pflags = (val & (1 << reg_bit))
            ? GPIO_PIN_INPUT : GPIO_PIN_OUTPUT;
 
        reg_addr = TCA6416_REG_ADDR(pin, POLARITY_INV_REG);
 
        error = tca6416_read(dev, reg_addr, &val);
        if (error != 0)
                return (error);
 
        if (val & (1 << reg_bit))
                *pflags |= GPIO_PIN_INVIN;
 
        return (0);
}
 
static int
tca6416_pin_setflags(device_t dev, uint32_t pin, uint32_t flags)
{
        uint8_t reg_addr, inv_reg_addr, reg_bit, val, inv_val;
        struct tca6416_softc *sc;
        int error;
 
        sc = device_get_softc(dev);
 
        if (pin >= NUM_PINS)
                return (EINVAL);
 
        reg_addr = TCA6416_REG_ADDR(pin, CONF_REG);
        inv_reg_addr = TCA6416_REG_ADDR(pin, POLARITY_INV_REG);
        reg_bit = TCA6416_BIT_FROM_PIN(pin);
 
        mtx_lock(&sc->mtx);
 
        error = tca6416_read(dev, reg_addr, &val);
        if (error != 0)
                goto fail;
        error = tca6416_read(dev, inv_reg_addr, &inv_val);
        if (error != 0)
                goto fail;
 
        if (flags & GPIO_PIN_INPUT)
                val |= (1 << reg_bit);
        else if (flags & GPIO_PIN_OUTPUT)
                val &= ~(1 << reg_bit);
 
        if (flags & GPIO_PIN_INVIN)
                inv_val |= (1 << reg_bit);
        else
                inv_val &= ~(1 << reg_bit);
 
        error = tca6416_write(dev, reg_addr, val);
        if (error != 0)
                goto fail;
        error = tca6416_write(dev, inv_reg_addr, val);
 
fail:
        mtx_unlock(&sc->mtx);
        return (error);
}
 
static int
tca6416_pin_getname(device_t dev, uint32_t pin, char *name)
{
 
        if (pin >= NUM_PINS || name == NULL)
                return (EINVAL);
 
        snprintf(name, GPIOMAXNAME, "gpio_P%d%d", pin / PINS_PER_REG,
            pin % PINS_PER_REG);
 
        return (0);
}
 
static int
tca6416_pin_get(device_t dev, uint32_t pin, unsigned int *pval)
{
        struct tca6416_softc *sc;
        uint8_t reg_bit, reg_addr, reg_pvalue;
        int error;
 
        sc = device_get_softc(dev);
 
        if (pin >= NUM_PINS || pval == NULL)
                return (EINVAL);
 
        reg_bit = TCA6416_BIT_FROM_PIN(pin);
        reg_addr = TCA6416_REG_ADDR(pin, IN_PORT_REG);
 
        dbg_dev_printf(dev, "Reading pin %u pvalue.", pin);
 
        error = tca6416_read(dev, reg_addr, &reg_pvalue);
        if (error != 0)
                return (error);
 
        *pval = reg_pvalue & (1 << reg_bit) ? 1 : 0;
 
        return (0);
}
 
static int
tca6416_pin_set(device_t dev, uint32_t pin, unsigned int val)
{
        struct tca6416_softc *sc;
        uint8_t reg_addr, reg_bit, reg_value;
        int error;
 
        sc = device_get_softc(dev);
 
        if (pin >= NUM_PINS)
                return (EINVAL);
 
        reg_addr = TCA6416_REG_ADDR(pin , OUT_PORT_REG);
        reg_bit = TCA6416_BIT_FROM_PIN(pin);
 
        dbg_dev_printf(dev, "Setting pin: %u to %u\n", pin, val);
 
        mtx_lock(&sc->mtx);
 
        error = tca6416_read(dev, reg_addr, &reg_value);
        if (error != 0) {
                dbg_dev_printf(dev, "Failed to read from register.\n");
                mtx_unlock(&sc->mtx);
                return (error);
        }
 
        if (val != 0)
                reg_value |= (1 << reg_bit);
        else
                reg_value &= ~(1 << reg_bit);
 
 
        error = tca6416_write(dev, reg_addr, reg_value);
        if (error != 0) {
                dbg_dev_printf(dev, "Could not write to register.\n");
                mtx_unlock(&sc->mtx);
                return (error);
        }
 
        mtx_unlock(&sc->mtx);
 
        return (0);
}
 
static int
tca6416_pin_toggle(device_t dev, uint32_t pin)
{
        struct tca6416_softc *sc;
        int error;
        uint8_t reg_addr, reg_bit, reg_value;
 
        sc = device_get_softc(dev);
 
        if (pin >= NUM_PINS)
                return (EINVAL);
 
        reg_addr = TCA6416_REG_ADDR(pin, OUT_PORT_REG);
        reg_bit = TCA6416_BIT_FROM_PIN(pin);
 
        dbg_dev_printf(dev, "Toggling pin: %d\n", pin);
 
        mtx_lock(&sc->mtx);
 
        error = tca6416_read(dev, reg_addr, &reg_value);
        if (error != 0) {
                mtx_unlock(&sc->mtx);
                dbg_dev_printf(dev, "Cannot read from register.\n");
                return (error);
        }
 
        reg_value ^= (1 << reg_bit);
 
        error = tca6416_write(dev, reg_addr, reg_value);
        if (error != 0)
                dbg_dev_printf(dev, "Cannot write to register.\n");
 
        mtx_unlock(&sc->mtx);
 
        return (error);
}
 
#ifdef DEBUG
static void
tca6416_regdump_setup(device_t dev)
{
        struct sysctl_ctx_list *ctx;
        struct sysctl_oid *node;
 
        ctx = device_get_sysctl_ctx(dev);
        node = device_get_sysctl_tree(dev);
 
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(node), OID_AUTO, "in_reg_1",
            CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, dev, IN_PORT_REG,
            tca6416_regdump_sysctl, "A", "Input port 1");
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(node), OID_AUTO, "in_reg_2",
            CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, dev,
            IN_PORT_REG | 1, tca6416_regdump_sysctl, "A", "Input port 2");
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(node), OID_AUTO, "out_reg_1",
            CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, dev, OUT_PORT_REG,
            tca6416_regdump_sysctl, "A", "Output port 1");
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(node), OID_AUTO, "out_reg_2",
            CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, dev, OUT_PORT_REG
            | 1, tca6416_regdump_sysctl, "A", "Output port 2");
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(node), OID_AUTO, "pol_inv_1",
            CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, dev,
            POLARITY_INV_REG, tca6416_regdump_sysctl, "A", "Polarity inv 1");
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(node), OID_AUTO, "pol_inv_2",
            CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, dev,
            POLARITY_INV_REG | 1, tca6416_regdump_sysctl, "A",
            "Polarity inv 2");
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(node), OID_AUTO, "conf_reg_1",
            CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, dev,
            CONF_REG, tca6416_regdump_sysctl, "A", "Configuration 1");
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(node), OID_AUTO, "conf_reg_2",
            CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, dev,
            CONF_REG | 1, tca6416_regdump_sysctl, "A", "Configuration 2");
}
 
static int
tca6416_regdump_sysctl(SYSCTL_HANDLER_ARGS)
{
        device_t dev;
        char buf[5];
        struct tca6416_softc *sc;
        int len, error;
        uint8_t reg, regval;
 
        dev = (device_t)arg1;
        reg = (uint8_t)arg2;
        sc = device_get_softc(dev);
 
 
        error = tca6416_read(dev, reg, &regval);
        if (error != 0) {
                return (error);
        }
 
        len = snprintf(buf, 5, "0x%02x", regval);
 
        error = sysctl_handle_string(oidp, buf, len, req);
 
        return (error);
}
#endif