// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Apple Motion Sensor driver (PMU variant)
 *
 * Copyright (C) 2006 Michael Hanselmann (linux-kernel@hansmi.ch)
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/adb.h>
#include <linux/pmu.h>

#include "ams.h"

/* Attitude */
#define AMS_X                   0x00
#define AMS_Y                   0x01
#define AMS_Z                   0x02

/* Not exactly known, maybe chip vendor */
#define AMS_VENDOR              0x03

/* Freefall registers */
#define AMS_FF_CLEAR            0x04
#define AMS_FF_ENABLE           0x05
#define AMS_FF_LOW_LIMIT        0x06
#define AMS_FF_DEBOUNCE         0x07

/* Shock registers */
#define AMS_SHOCK_CLEAR         0x08
#define AMS_SHOCK_ENABLE        0x09
#define AMS_SHOCK_HIGH_LIMIT    0x0a
#define AMS_SHOCK_DEBOUNCE      0x0b

/* Global interrupt and power control register */
#define AMS_CONTROL             0x0c

static u8 ams_pmu_cmd;

static void ams_pmu_req_complete(struct adb_request *req)
{
        complete((struct completion *)req->arg);
}

/* Only call this function from task context */
static void ams_pmu_set_register(u8 reg, u8 value)
{
        static struct adb_request req;
        DECLARE_COMPLETION(req_complete);

        req.arg = &req_complete;
        if (pmu_request(&req, ams_pmu_req_complete, 4, ams_pmu_cmd, 0x00, reg, value))
                return;

        wait_for_completion(&req_complete);
}

/* Only call this function from task context */
static u8 ams_pmu_get_register(u8 reg)
{
        static struct adb_request req;
        DECLARE_COMPLETION(req_complete);

        req.arg = &req_complete;
        if (pmu_request(&req, ams_pmu_req_complete, 3, ams_pmu_cmd, 0x01, reg))
                return 0;

        wait_for_completion(&req_complete);

        if (req.reply_len > 0)
                return req.reply[0];
        else
                return 0;
}

/* Enables or disables the specified interrupts */
static void ams_pmu_set_irq(enum ams_irq reg, char enable)
{
        if (reg & AMS_IRQ_FREEFALL) {
                u8 val = ams_pmu_get_register(AMS_FF_ENABLE);
                if (enable)
                        val |= 0x80;
                else
                        val &= ~0x80;
                ams_pmu_set_register(AMS_FF_ENABLE, val);
        }

        if (reg & AMS_IRQ_SHOCK) {
                u8 val = ams_pmu_get_register(AMS_SHOCK_ENABLE);
                if (enable)
                        val |= 0x80;
                else
                        val &= ~0x80;
                ams_pmu_set_register(AMS_SHOCK_ENABLE, val);
        }

        if (reg & AMS_IRQ_GLOBAL) {
                u8 val = ams_pmu_get_register(AMS_CONTROL);
                if (enable)
                        val |= 0x80;
                else
                        val &= ~0x80;
                ams_pmu_set_register(AMS_CONTROL, val);
        }
}

static void ams_pmu_clear_irq(enum ams_irq reg)
{
        if (reg & AMS_IRQ_FREEFALL)
                ams_pmu_set_register(AMS_FF_CLEAR, 0x00);

        if (reg & AMS_IRQ_SHOCK)
                ams_pmu_set_register(AMS_SHOCK_CLEAR, 0x00);
}

static u8 ams_pmu_get_vendor(void)
{
        return ams_pmu_get_register(AMS_VENDOR);
}

static void ams_pmu_get_xyz(s8 *x, s8 *y, s8 *z)
{
        *x = ams_pmu_get_register(AMS_X);
        *y = ams_pmu_get_register(AMS_Y);
        *z = ams_pmu_get_register(AMS_Z);
}

static void ams_pmu_exit(void)
{
        ams_sensor_detach();

        /* Disable interrupts */
        ams_pmu_set_irq(AMS_IRQ_ALL, 0);

        /* Clear interrupts */
        ams_pmu_clear_irq(AMS_IRQ_ALL);

        ams_info.has_device = 0;

        printk(KERN_INFO "ams: Unloading\n");
}

int __init ams_pmu_init(struct device_node *np)
{
        const u32 *prop;
        int result;

        /* Set implementation stuff */
        ams_info.of_node = np;
        ams_info.exit = ams_pmu_exit;
        ams_info.get_vendor = ams_pmu_get_vendor;
        ams_info.get_xyz = ams_pmu_get_xyz;
        ams_info.clear_irq = ams_pmu_clear_irq;
        ams_info.bustype = BUS_HOST;

        /* Get PMU command, should be 0x4e, but we can never know */
        prop = of_get_property(ams_info.of_node, "reg", NULL);
        if (!prop)
                return -ENODEV;

        ams_pmu_cmd = ((*prop) >> 8) & 0xff;

        /* Disable interrupts */
        ams_pmu_set_irq(AMS_IRQ_ALL, 0);

        /* Clear interrupts */
        ams_pmu_clear_irq(AMS_IRQ_ALL);

        result = ams_sensor_attach();
        if (result < 0)
                return result;

        /* Set default values */
        ams_pmu_set_register(AMS_FF_LOW_LIMIT, 0x15);
        ams_pmu_set_register(AMS_FF_ENABLE, 0x08);
        ams_pmu_set_register(AMS_FF_DEBOUNCE, 0x14);

        ams_pmu_set_register(AMS_SHOCK_HIGH_LIMIT, 0x60);
        ams_pmu_set_register(AMS_SHOCK_ENABLE, 0x0f);
        ams_pmu_set_register(AMS_SHOCK_DEBOUNCE, 0x14);

        ams_pmu_set_register(AMS_CONTROL, 0x4f);

        /* Clear interrupts */
        ams_pmu_clear_irq(AMS_IRQ_ALL);

        ams_info.has_device = 1;

        /* Enable interrupts */
        ams_pmu_set_irq(AMS_IRQ_ALL, 1);

        printk(KERN_INFO "ams: Found PMU based motion sensor\n");

        return 0;
}