/*      $OpenBSD: ofw_regulator.c,v 1.20 2024/06/14 20:00:32 kettenis Exp $     */
/*
 * Copyright (c) 2016 Mark Kettenis
 *
 * 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/types.h>
#include <sys/systm.h>
#include <sys/malloc.h>

#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_gpio.h>
#include <dev/ofw/ofw_pinctrl.h>
#include <dev/ofw/ofw_regulator.h>

#define REGULATOR_VOLTAGE       0
#define REGULATOR_CURRENT       1

LIST_HEAD(, regulator_device) regulator_devices =
        LIST_HEAD_INITIALIZER(regulator_devices);

LIST_HEAD(, regulator_notifier) regulator_notifiers =
        LIST_HEAD_INITIALIZER(regulator_notifiers);

int regulator_type(int);
uint32_t regulator_gpio_get(int);
int regulator_gpio_set(int, uint32_t);
void regulator_do_notify(uint32_t, uint32_t);

void
regulator_register(struct regulator_device *rd)
{
        rd->rd_volt_min = OF_getpropint(rd->rd_node,
            "regulator-min-microvolt", 0);
        rd->rd_volt_max = OF_getpropint(rd->rd_node,
            "regulator-max-microvolt", ~0);
        KASSERT(rd->rd_volt_min <= rd->rd_volt_max);

        rd->rd_amp_min = OF_getpropint(rd->rd_node,
            "regulator-min-microamp", 0);
        rd->rd_amp_max = OF_getpropint(rd->rd_node,
            "regulator-max-microamp", ~0);
        KASSERT(rd->rd_amp_min <= rd->rd_amp_max);

        rd->rd_ramp_delay =
            OF_getpropint(rd->rd_node, "regulator-ramp-delay", 0);

        rd->rd_coupled =
            OF_getpropint(rd->rd_node, "regulator-coupled-with", 0);
        rd->rd_max_spread =
            OF_getpropint(rd->rd_node, "regulator-coupled-max-spread", 0);

        if (rd->rd_get_voltage && rd->rd_set_voltage) {
                uint32_t voltage = rd->rd_get_voltage(rd->rd_cookie);
                if (voltage < rd->rd_volt_min)
                        rd->rd_set_voltage(rd->rd_cookie, rd->rd_volt_min);
                if (voltage > rd->rd_volt_max)
                        rd->rd_set_voltage(rd->rd_cookie, rd->rd_volt_max);
        }

        if (rd->rd_get_current && rd->rd_set_current) {
                uint32_t current = rd->rd_get_current(rd->rd_cookie);
                if (current < rd->rd_amp_min)
                        rd->rd_set_current(rd->rd_cookie, rd->rd_amp_min);
                if (current > rd->rd_amp_max)
                        rd->rd_set_current(rd->rd_cookie, rd->rd_amp_max);
        }

        rd->rd_phandle = OF_getpropint(rd->rd_node, "phandle", 0);
        if (rd->rd_phandle == 0)
                return;

        LIST_INSERT_HEAD(&regulator_devices, rd, rd_list);

        if (rd->rd_get_voltage) {
                regulator_do_notify(rd->rd_phandle,
                    regulator_get_voltage(rd->rd_phandle));
        }
        if (rd->rd_get_current) {
                regulator_do_notify(rd->rd_phandle,
                    regulator_get_current(rd->rd_phandle));
        }
}

int
regulator_type(int node)
{
        char type[16] = { 0 };

        OF_getprop(node, "regulator-type", type, sizeof(type));
        if (strcmp(type, "current") == 0)
                return REGULATOR_CURRENT;

        return REGULATOR_VOLTAGE;
}

int
regulator_fixed_set(int node, int enable)
{
        uint32_t *gpio;
        uint32_t startup_delay;
        int len;
        char *prop = "gpio";

        /*
         * This regulator may rely on another. That "parent" regulator
         * may be used by multiple other devices/regulators, so unless
         * we refcnt use of a regulator we can only turn it on.
         */
        if (enable)
                regulator_enable(OF_getpropint(node, "vin-supply", 0));

        pinctrl_byname(node, "default");

        /* The "gpio"/"gpios" property is optional. */
        len = OF_getproplen(node, prop);
        if (len < 0) {
                prop = "gpios";
                len = OF_getproplen(node, prop);
                if (len < 0)
                        return 0;
        }

        /*
         * We deliberately ignore the "enable-active-high" property
         * here.  Its presence (or absence) is used to override the
         * polarity encoded by the GPIO flags in the device tree.  But
         * supporting this behaviour is awkward since it would require
         * interpreting the GPIO flags here which would be a layer
         * violation since those flags may be driver-specific.  In
         * practice the presence of "enable-active-high" is always
         * aligned with the polarity encoded by the GPIO flags and any
         * discrepancy is considered to be a bug by the Linux device
         * tree maintainers.
         */

        gpio = malloc(len, M_TEMP, M_WAITOK);
        OF_getpropintarray(node, prop, gpio, len);
        gpio_controller_config_pin(gpio, GPIO_CONFIG_OUTPUT);
        if (enable)
                gpio_controller_set_pin(gpio, 1);
        else
                gpio_controller_set_pin(gpio, 0);
        free(gpio, M_TEMP, len);

        startup_delay = OF_getpropint(node, "startup-delay-us", 0);
        if (enable && startup_delay > 0)
                delay(startup_delay);

        return 0;
}

int
regulator_set(uint32_t phandle, int enable)
{
        struct regulator_device *rd;
        int node;

        if (phandle == 0)
                return ENODEV;

        node = OF_getnodebyphandle(phandle);
        if (node == 0)
                return ENODEV;

        /* Never turn off regulators that should always be on. */
        if (OF_getproplen(node, "regulator-always-on") == 0 && !enable)
                return 0;

        LIST_FOREACH(rd, &regulator_devices, rd_list) {
                if (rd->rd_phandle == phandle)
                        break;
        }

        if (rd && rd->rd_enable)
                return rd->rd_enable(rd->rd_cookie, enable);

        if (OF_is_compatible(node, "regulator-fixed"))
                return regulator_fixed_set(node, enable);

        return ENODEV;
}

int
regulator_enable(uint32_t phandle)
{
        return regulator_set(phandle, 1);
}

int
regulator_disable(uint32_t phandle)
{
        return regulator_set(phandle, 0);
}

uint32_t
regulator_get_voltage(uint32_t phandle)
{
        struct regulator_device *rd;
        int node;

        if (phandle == 0)
                return 0;

        LIST_FOREACH(rd, &regulator_devices, rd_list) {
                if (rd->rd_phandle == phandle)
                        break;
        }

        if (rd && rd->rd_get_voltage)
                return rd->rd_get_voltage(rd->rd_cookie);

        node = OF_getnodebyphandle(phandle);
        if (node == 0)
                return 0;

        if (OF_is_compatible(node, "regulator-fixed"))
                return OF_getpropint(node, "regulator-min-microvolt", 0);

        if (OF_is_compatible(node, "regulator-gpio") &&
            regulator_type(node) == REGULATOR_VOLTAGE)
                return regulator_gpio_get(node);

        return 0;
}

int
regulator_set_voltage(uint32_t phandle, uint32_t voltage)
{
        struct regulator_device *rd;
        uint32_t old, delta;
        int error, node;

        if (phandle == 0)
                return ENODEV;

        LIST_FOREACH(rd, &regulator_devices, rd_list) {
                if (rd->rd_phandle == phandle)
                        break;
        }

        /* Check limits. */
        if (rd && (voltage < rd->rd_volt_min || voltage > rd->rd_volt_max))
                return EINVAL;

        /* XXX Coupled regulators are unsupported for now. */
        if (rd && rd->rd_coupled)
                return ENOTSUP;

        if (rd && rd->rd_set_voltage) {
                regulator_do_notify(rd->rd_phandle, voltage);

                old = rd->rd_get_voltage(rd->rd_cookie);
                error = rd->rd_set_voltage(rd->rd_cookie, voltage);
                if (voltage > old && rd->rd_ramp_delay > 0) {
                        delta = voltage - old;
                        delay(howmany(delta, rd->rd_ramp_delay));
                }

                regulator_do_notify(rd->rd_phandle, voltage);
                return error;
        }

        node = OF_getnodebyphandle(phandle);
        if (node == 0)
                return ENODEV;

        if (OF_is_compatible(node, "regulator-fixed") &&
            OF_getpropint(node, "regulator-min-microvolt", 0) == voltage)
                return 0;

        if (OF_is_compatible(node, "regulator-gpio") &&
            regulator_type(node) == REGULATOR_VOLTAGE)
                return regulator_gpio_set(node, voltage);

        return ENODEV;
}

uint32_t
regulator_get_current(uint32_t phandle)
{
        struct regulator_device *rd;
        int node;

        if (phandle == 0)
                return 0;

        LIST_FOREACH(rd, &regulator_devices, rd_list) {
                if (rd->rd_phandle == phandle)
                        break;
        }

        if (rd && rd->rd_get_current)
                return rd->rd_get_current(rd->rd_cookie);

        node = OF_getnodebyphandle(phandle);
        if (node == 0)
                return 0;

        if (OF_is_compatible(node, "regulator-fixed"))
                return OF_getpropint(node, "regulator-min-microamp", 0);

        if (OF_is_compatible(node, "regulator-gpio") &&
            regulator_type(node) == REGULATOR_CURRENT)
                return regulator_gpio_get(node);

        return 0;
}

int
regulator_set_current(uint32_t phandle, uint32_t current)
{
        struct regulator_device *rd;
        uint32_t old, delta;
        int error, node;

        if (phandle == 0)
                return ENODEV;

        LIST_FOREACH(rd, &regulator_devices, rd_list) {
                if (rd->rd_phandle == phandle)
                        break;
        }

        /* Check limits. */
        if (rd && (current < rd->rd_amp_min || current > rd->rd_amp_max))
                return EINVAL;

        if (rd && rd->rd_set_current) {
                regulator_do_notify(rd->rd_phandle, current);

                old = rd->rd_get_current(rd->rd_cookie);
                error = rd->rd_set_current(rd->rd_cookie, current);
                if (current > old && rd->rd_ramp_delay > 0) {
                        delta = current - old;
                        delay(howmany(delta, rd->rd_ramp_delay));
                }

                regulator_do_notify(rd->rd_phandle, current);
                return error;
        }

        node = OF_getnodebyphandle(phandle);
        if (node == 0)
                return ENODEV;

        if (OF_is_compatible(node, "regulator-fixed") &&
            OF_getpropint(node, "regulator-min-microamp", 0) == current)
                return 0;

        if (OF_is_compatible(node, "regulator-gpio") &&
            regulator_type(node) == REGULATOR_CURRENT)
                return regulator_gpio_set(node, current);

        return ENODEV;
}

uint32_t
regulator_gpio_get(int node)
{
        uint32_t *gpio, *gpios, *states;
        uint32_t idx, value;
        int glen, slen, i;

        pinctrl_byname(node, "default");

        if ((glen = OF_getproplen(node, "gpios")) <= 0)
                return EINVAL;
        if ((slen = OF_getproplen(node, "states")) <= 0)
                return EINVAL;

        if (slen % (2 * sizeof(uint32_t)) != 0)
                return EINVAL;

        gpios = malloc(glen, M_TEMP, M_WAITOK);
        states = malloc(slen, M_TEMP, M_WAITOK);

        OF_getpropintarray(node, "gpios", gpios, glen);
        OF_getpropintarray(node, "states", states, slen);

        i = 0;
        idx = 0;
        gpio = gpios;
        while (gpio && gpio < gpios + (glen / sizeof(uint32_t))) {
                if (gpio_controller_get_pin(gpio))
                        idx |= (1 << i);
                gpio = gpio_controller_next_pin(gpio);
                i++;
        }

        value = 0;
        for (i = 0; i < slen / (2 * sizeof(uint32_t)); i++) {
                if (states[2 * i + 1] == idx) {
                        value = states[2 * i];
                        break;
                }
        }
        if (i >= slen / (2 * sizeof(uint32_t)))
                return 0;

        free(gpios, M_TEMP, glen);
        free(states, M_TEMP, slen);

        return value;
}

int
regulator_gpio_set(int node, uint32_t value)
{
        uint32_t phandle = OF_getpropint(node, "phandle", 0);
        uint32_t *gpio, *gpios, *states;
        uint32_t min, max;
        uint32_t idx;
        int glen, slen, i;

        pinctrl_byname(node, "default");

        if (regulator_type(node) == REGULATOR_VOLTAGE) {
                min = OF_getpropint(node, "regulator-min-microvolt", 0);
                max = OF_getpropint(node, "regulator-max-microvolt", 0);
        }

        if (regulator_type(node) == REGULATOR_CURRENT) {
                min = OF_getpropint(node, "regulator-min-microamp", 0);
                max = OF_getpropint(node, "regulator-max-microamp", 0);
        }

        /* Check limits. */
        if (value < min || value > max)
                return EINVAL;

        if ((glen = OF_getproplen(node, "gpios")) <= 0)
                return EINVAL;
        if ((slen = OF_getproplen(node, "states")) <= 0)
                return EINVAL;

        if (slen % (2 * sizeof(uint32_t)) != 0)
                return EINVAL;

        gpios = malloc(glen, M_TEMP, M_WAITOK);
        states = malloc(slen, M_TEMP, M_WAITOK);

        OF_getpropintarray(node, "gpios", gpios, glen);
        OF_getpropintarray(node, "states", states, slen);

        idx = 0;
        for (i = 0; i < slen / (2 * sizeof(uint32_t)); i++) {
                if (states[2 * i] < min || states[2 * i] > max)
                        continue;
                if (states[2 * i] == value) {
                        idx = states[2 * i + 1];
                        break;
                }
        }
        if (i >= slen / (2 * sizeof(uint32_t)))
                return EINVAL;

        regulator_do_notify(phandle, value);
        
        i = 0;
        gpio = gpios;
        while (gpio && gpio < gpios + (glen / sizeof(uint32_t))) {
                gpio_controller_set_pin(gpio, !!(idx & (1 << i)));
                gpio = gpio_controller_next_pin(gpio);
                i++;
        }

        regulator_do_notify(phandle, value);

        free(gpios, M_TEMP, glen);
        free(states, M_TEMP, slen);

        return 0;
}

void
regulator_notify(struct regulator_notifier *rn)
{
        LIST_INSERT_HEAD(&regulator_notifiers, rn, rn_list);
}

void
regulator_do_notify(uint32_t phandle, uint32_t value)
{
        struct regulator_notifier *rn;

        LIST_FOREACH(rn, &regulator_notifiers, rn_list) {
                if (rn->rn_phandle == phandle)
                        rn->rn_notify(rn->rn_cookie, value);
        }
}