/* $NetBSD: axp809.c,v 1.3 2019/07/27 16:02:27 thorpej Exp $ */

/*-
 * Copyright (c) 2014 Jared D. McNeill <jmcneill@invisible.ca>
 * All rights reserved.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#define AXP_DEBUG

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: axp809.c,v 1.3 2019/07/27 16:02:27 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/conf.h>
#include <sys/bus.h>
#include <sys/kmem.h>

#include <dev/i2c/i2cvar.h>
#include <dev/i2c/axp809.h>

#define AXP_GPIO1_CTRL_REG      0x92
#define AXP_GPIO1LDO_CTRL_REG   0x93

struct axp809_ctrl {
        device_t        c_dev;

        const char *    c_name;
        u_int           c_min;
        u_int           c_max;
        u_int           c_step1;
        u_int           c_step1cnt;
        u_int           c_step2;
        u_int           c_step2cnt;

        uint8_t         c_enable_reg;
        uint8_t         c_enable_mask;

        uint8_t         c_voltage_reg;
        uint8_t         c_voltage_mask;
};

#define AXP_CTRL(name, min, max, step, ereg, emask, vreg, vmask)        \
        { .c_name = (name), .c_min = (min), .c_max = (max),             \
          .c_step1 = (step), .c_step1cnt = (((max) - (min)) / (step)) + 1, \
          .c_step2 = 0, .c_step2cnt = 0,                                \
          .c_enable_reg = AXP_##ereg##_REG, .c_enable_mask = (emask),   \
          .c_voltage_reg = AXP_##vreg##_REG, .c_voltage_mask = (vmask) }

#define AXP_CTRL2(name, min, max, step1, step1cnt, step2, step2cnt, ereg, emask, vreg, vmask) \
        { .c_name = (name), .c_min = (min), .c_max = (max),             \
          .c_step1 = (step1), .c_step1cnt = (step1cnt),                 \
          .c_step2 = (step2), .c_step2cnt = (step2cnt),                 \
          .c_enable_reg = AXP_##ereg##_REG, .c_enable_mask = (emask),   \
          .c_voltage_reg = AXP_##vreg##_REG, .c_voltage_mask = (vmask) }

static const struct axp809_ctrl axp809_ctrls[] = {
        AXP_CTRL("GPIO1", 700, 3300, 100,
                GPIO1_CTRL, __BIT(0), GPIO1LDO_CTRL, __BITS(4,0)),
};

struct axp809_softc {
        device_t        sc_dev;
        i2c_tag_t       sc_i2c;
        i2c_addr_t      sc_addr;

        u_int           sc_nctrl;
        struct axp809_ctrl *sc_ctrl;
};

static int      axp809_match(device_t, cfdata_t, void *);
static void     axp809_attach(device_t, device_t, void *);

static int      axp809_read(struct axp809_softc *, uint8_t, uint8_t *);
static int      axp809_write(struct axp809_softc *, uint8_t, uint8_t);

static void     axp809_print(struct axp809_ctrl *c);

CFATTACH_DECL_NEW(axp809pm, sizeof(struct axp809_softc),
    axp809_match, axp809_attach, NULL, NULL);

static int
axp809_match(device_t parent, cfdata_t match, void *aux)
{
        struct i2c_attach_args *ia = aux;
        int match_result;

        if (iic_use_direct_match(ia, match, NULL, &match_result))
                return match_result;
        
        /* This device is direct-config only. */

        return 0;
}

static void
axp809_attach(device_t parent, device_t self, void *aux)
{
        struct axp809_softc *sc = device_private(self);
        struct i2c_attach_args *ia = aux;
        u_int n;

        sc->sc_dev = self;
        sc->sc_i2c = ia->ia_tag;
        sc->sc_addr = ia->ia_addr;

        aprint_naive("\n");
        aprint_normal("\n");

        sc->sc_nctrl = __arraycount(axp809_ctrls);
        sc->sc_ctrl = kmem_alloc(sizeof(axp809_ctrls), KM_SLEEP);
        memcpy(sc->sc_ctrl, axp809_ctrls, sizeof(axp809_ctrls));
        for (n = 0; n < sc->sc_nctrl; n++) {
                sc->sc_ctrl[n].c_dev = self;
        }

#ifdef AXP_DEBUG
        for (n = 0; n < sc->sc_nctrl; n++) {
                axp809_print(&sc->sc_ctrl[n]);
        }
#endif
}

static int
axp809_read(struct axp809_softc *sc, uint8_t reg, uint8_t *val)
{
        return iic_smbus_read_byte(sc->sc_i2c, sc->sc_addr, reg, val, 0);
}

static int
axp809_write(struct axp809_softc *sc, uint8_t reg, uint8_t val)
{
        return iic_smbus_write_byte(sc->sc_i2c, sc->sc_addr, reg, val, 0);
}

static void
axp809_print(struct axp809_ctrl *c)
{
        struct axp809_softc *sc = device_private(c->c_dev);
        u_int voltage;
        bool enabled;

        device_printf(sc->sc_dev, "%s:", c->c_name);
        if (c->c_voltage_reg) {
                if (axp809_get_voltage(c, &voltage)) {
                        printf(" [??? V]");
                } else {
                        printf(" [%d.%03dV]", voltage / 1000,
                            voltage % 1000);
                }
        }
        if (c->c_enable_reg) {
                if (axp809_is_enabled(c, &enabled)) {
                        printf(" [unknown state]");
                } else {
                        printf(" [%s]", enabled ? "ON" : "OFF");
                }
        }
        printf("\n");
}

struct axp809_ctrl *
axp809_lookup(device_t dev, const char *name)
{
        struct axp809_softc *sc = device_private(dev);
        struct axp809_ctrl *c;
        u_int n;

        for (n = 0; n < sc->sc_nctrl; n++) {
                c = &sc->sc_ctrl[n];
                if (strcmp(c->c_name, name) == 0) {
                        return c;
                }
        }

        return NULL;
}

int
axp809_set_voltage(struct axp809_ctrl *c, u_int min, u_int max)
{
        struct axp809_softc *sc = device_private(c->c_dev);
        u_int vol, reg_val;
        int nstep, error;
        uint8_t val;

        if (!c->c_voltage_mask)
                return EINVAL;

        if (min < c->c_min || min > c->c_max)
                return EINVAL;

        reg_val = 0;
        nstep = 1;
        vol = c->c_min;

        for (nstep = 0; nstep < c->c_step1cnt && vol < min; nstep++) {
                ++reg_val;
                vol += c->c_step1;
        }
        for (nstep = 0; nstep < c->c_step2cnt && vol < min; nstep++) {
                ++reg_val;
                vol += c->c_step2;
        }

        if (vol > max)
                return EINVAL;

        iic_acquire_bus(sc->sc_i2c, 0);
        if ((error = axp809_read(sc, c->c_voltage_reg, &val)) != 0)
                goto done;
        val &= ~c->c_voltage_mask;
        val |= __SHIFTIN(reg_val, c->c_voltage_mask);
        error = axp809_write(sc, c->c_voltage_reg, val);
done:
        iic_release_bus(sc->sc_i2c, 0);
#ifdef AXP_DEBUG
        if (error == 0)
                axp809_print(c);
#endif

        return error;
}

int
axp809_get_voltage(struct axp809_ctrl *c, u_int *pvol)
{
        struct axp809_softc *sc = device_private(c->c_dev);
        int reg_val, error;
        uint8_t val;

        if (!c->c_voltage_mask)
                return EINVAL;

        iic_acquire_bus(sc->sc_i2c, 0);
        error = axp809_read(sc, c->c_voltage_reg, &val);
        iic_release_bus(sc->sc_i2c, 0);
        if (error)
                return error;

        reg_val = __SHIFTOUT(val, c->c_voltage_mask);
        if (reg_val < c->c_step1cnt) {
                *pvol = c->c_min + reg_val * c->c_step1;
        } else {
                *pvol = c->c_min + (c->c_step1cnt * c->c_step1) +
                    ((reg_val - c->c_step1cnt) * c->c_step2);
        }

        return 0;
}

int
axp809_is_enabled(struct axp809_ctrl *c, bool *penabled)
{
        struct axp809_softc *sc = device_private(c->c_dev);
        uint8_t val;
        int error;

        if (!c->c_enable_mask)
                return EINVAL;

        iic_acquire_bus(sc->sc_i2c, 0);
        error = axp809_read(sc, c->c_enable_reg, &val);
        iic_release_bus(sc->sc_i2c, 0);
        if (error)
                return error;

        *penabled = !!(val & c->c_enable_mask);
        return 0;
}

int
axp809_enable(struct axp809_ctrl *c)
{
        struct axp809_softc *sc = device_private(c->c_dev);
        uint8_t val;
        int error;

        if (!c->c_enable_mask)
                return EINVAL;

        iic_acquire_bus(sc->sc_i2c, 0);
        if ((error = axp809_read(sc, c->c_enable_reg, &val)) != 0)
                goto done;
        val |= c->c_enable_mask;
        error = axp809_write(sc, c->c_enable_reg, val);
done:
        iic_release_bus(sc->sc_i2c, 0);
#ifdef AXP_DEBUG
        if (error == 0)
                axp809_print(c);
#endif

        return error;
}

int
axp809_disable(struct axp809_ctrl *c)
{
        struct axp809_softc *sc = device_private(c->c_dev);
        uint8_t val;
        int error;

        if (!c->c_enable_mask)
                return EINVAL;

        iic_acquire_bus(sc->sc_i2c, 0);
        if ((error = axp809_read(sc, c->c_enable_reg, &val)) != 0)
                goto done;
        val &= ~c->c_enable_mask;
        error = axp809_write(sc, c->c_enable_reg, val);
done:
        iic_release_bus(sc->sc_i2c, 0);
#ifdef AXP_DEBUG
        if (error == 0)
                axp809_print(c);
#endif

        return error;
}