/* $NetBSD: sy8106a.c,v 1.8 2021/01/27 02:29:48 thorpej Exp $ */

/*-
* Copyright (c) 2017 Jared McNeill <[email protected]>
* 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.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sy8106a.c,v 1.8 2021/01/27 02:29:48 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/fdt/fdtvar.h>

#define VOUT1_SEL               0x01
#define  SEL_GO                 __BIT(7)
#define  SEL_VOLTAGE            __BITS(6,0)
#define   SEL_VOLTAGE_BASE      680000  /* uV */
#define   SEL_VOLTAGE_STEP      10000   /* uV */
#define VOUT_COM                0x02
#define  COM_DISABLE            __BIT(0)
#define SYS_STATUS              0x06

struct sy8106a_softc {
       device_t        sc_dev;
       i2c_tag_t       sc_i2c;
       i2c_addr_t      sc_addr;
       int             sc_phandle;

       u_int           sc_ramp_delay;
};

static const struct device_compatible_entry compat_data[] = {
       { .compat = "silergy,sy8106a" },
       DEVICE_COMPAT_EOL
};

static uint8_t
sy8106a_read(struct sy8106a_softc *sc, uint8_t reg, int flags)
{
       uint8_t val = 0;
       int error;

       error = iic_exec(sc->sc_i2c, I2C_OP_READ_WITH_STOP, sc->sc_addr,
           &reg, 1, &val, 1, flags);
       if (error != 0)
               aprint_error_dev(sc->sc_dev, "error reading reg %#x: %d\n", reg, error);

       return val;
}

static void
sy8106a_write(struct sy8106a_softc *sc, uint8_t reg, uint8_t val, int flags)
{
       uint8_t buf[2];
       int error;

       buf[0] = reg;
       buf[1] = val;

       error = iic_exec(sc->sc_i2c, I2C_OP_WRITE_WITH_STOP, sc->sc_addr,
           NULL, 0, buf, 2, flags);
       if (error != 0)
               aprint_error_dev(sc->sc_dev, "error writing reg %#x: %d\n", reg, error);
}

#define I2C_READ(sc, reg)       sy8106a_read((sc), (reg), 0)
#define I2C_WRITE(sc, reg, val) sy8106a_write((sc), (reg), (val), 0)
#define I2C_LOCK(sc)            iic_acquire_bus((sc)->sc_i2c, 0)
#define I2C_UNLOCK(sc)          iic_release_bus((sc)->sc_i2c, 0)

static int
sy8106a_acquire(device_t dev)
{
       return 0;
}

static void
sy8106a_release(device_t dev)
{
}

static int
sy8106a_enable(device_t dev, bool enable)
{
       struct sy8106a_softc * const sc = device_private(dev);
       uint8_t val;

       I2C_LOCK(sc);
       val = I2C_READ(sc, VOUT_COM);
       if (enable)
               val &= ~COM_DISABLE;
       else
               val |= COM_DISABLE;
       I2C_WRITE(sc, VOUT_COM, val);
       I2C_UNLOCK(sc);

       if (sc->sc_ramp_delay)
               delay(sc->sc_ramp_delay);

       return 0;
}

static int
sy8106a_set_voltage(device_t dev, u_int min_uvol, u_int max_uvol)
{
       struct sy8106a_softc * const sc = device_private(dev);
       uint8_t val, oval;
       u_int cur_uvol;

       I2C_LOCK(sc);

       /* Get current voltage */
       oval = I2C_READ(sc, VOUT1_SEL);
       cur_uvol = __SHIFTOUT(oval, SEL_VOLTAGE) * SEL_VOLTAGE_STEP +
           SEL_VOLTAGE_BASE;

       /* Set new voltage */
       val = SEL_GO | ((min_uvol - SEL_VOLTAGE_BASE) / SEL_VOLTAGE_STEP);
       I2C_WRITE(sc, VOUT1_SEL, val);

       I2C_UNLOCK(sc);

       /* Time to delay is based on the number of voltage steps */
       if (sc->sc_ramp_delay)
               delay((abs(cur_uvol - min_uvol) / SEL_VOLTAGE_STEP) * sc->sc_ramp_delay);

       return 0;
}

static int
sy8106a_get_voltage(device_t dev, u_int *puvol)
{
       struct sy8106a_softc * const sc = device_private(dev);
       uint8_t val;

       I2C_LOCK(sc);
       val = I2C_READ(sc, VOUT1_SEL);
       I2C_UNLOCK(sc);

       *puvol = __SHIFTOUT(val, SEL_VOLTAGE) * SEL_VOLTAGE_STEP +
           SEL_VOLTAGE_BASE;

       return 0;
}

static struct fdtbus_regulator_controller_func sy8106a_funcs = {
       .acquire = sy8106a_acquire,
       .release = sy8106a_release,
       .enable = sy8106a_enable,
       .set_voltage = sy8106a_set_voltage,
       .get_voltage = sy8106a_get_voltage,
};

static int
sy8106a_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, compat_data, &match_result))
               return match_result;

       return 0;
}

static void
sy8106a_attach(device_t parent, device_t self, void *aux)
{
       struct sy8106a_softc * const sc = device_private(self);
       struct i2c_attach_args *ia = aux;

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

       aprint_naive("\n");
       aprint_normal(": Silergy SY8106A regulator\n");

       of_getprop_uint32(sc->sc_phandle, "regulator-ramp-delay",
           &sc->sc_ramp_delay);

       fdtbus_register_regulator_controller(self, sc->sc_phandle,
           &sy8106a_funcs);
}

CFATTACH_DECL_NEW(sy8106a, sizeof(struct sy8106a_softc),
   sy8106a_match, sy8106a_attach, NULL, NULL);