// SPDX-License-Identifier: GPL-2.0+
//
// Driver for the IMX SNVS ON/OFF Power Key
// Copyright (C) 2015 Freescale Semiconductor, Inc. All Rights Reserved.

#include <linux/clk.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/pm_wakeirq.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>

#define SNVS_HPVIDR1_REG        0xBF8
#define SNVS_LPSR_REG           0x4C    /* LP Status Register */
#define SNVS_LPCR_REG           0x38    /* LP Control Register */
#define SNVS_HPSR_REG           0x14
#define SNVS_HPSR_BTN           BIT(6)
#define SNVS_LPSR_SPO           BIT(18)
#define SNVS_LPCR_DEP_EN        BIT(5)
#define SNVS_LPCR_BPT_SHIFT     16
#define SNVS_LPCR_BPT_MASK      (3 << SNVS_LPCR_BPT_SHIFT)

#define DEBOUNCE_TIME           30
#define REPEAT_INTERVAL         60

struct pwrkey_drv_data {
        struct regmap *snvs;
        int irq;
        int keycode;
        int keystate;  /* 1:pressed */
        int wakeup;
        struct timer_list check_timer;
        struct input_dev *input;
        u8 minor_rev;
};

static void imx_imx_snvs_check_for_events(struct timer_list *t)
{
        struct pwrkey_drv_data *pdata = timer_container_of(pdata, t,
                                                           check_timer);
        struct input_dev *input = pdata->input;
        u32 state;

        regmap_read(pdata->snvs, SNVS_HPSR_REG, &state);
        state = state & SNVS_HPSR_BTN ? 1 : 0;

        /* only report new event if status changed */
        if (state ^ pdata->keystate) {
                pdata->keystate = state;
                input_event(input, EV_KEY, pdata->keycode, state);
                input_sync(input);
                pm_relax(pdata->input->dev.parent);
        }

        /* repeat check if pressed long */
        if (state) {
                mod_timer(&pdata->check_timer,
                          jiffies + msecs_to_jiffies(REPEAT_INTERVAL));
        }
}

static irqreturn_t imx_snvs_pwrkey_interrupt(int irq, void *dev_id)
{
        struct platform_device *pdev = dev_id;
        struct pwrkey_drv_data *pdata = platform_get_drvdata(pdev);
        struct input_dev *input = pdata->input;
        u32 lp_status;

        pm_wakeup_event(input->dev.parent, 0);

        regmap_read(pdata->snvs, SNVS_LPSR_REG, &lp_status);
        if (lp_status & SNVS_LPSR_SPO) {
                if (pdata->minor_rev == 0) {
                        /*
                         * The first generation i.MX6 SoCs only sends an
                         * interrupt on button release. To mimic power-key
                         * usage, we'll prepend a press event.
                         */
                        input_report_key(input, pdata->keycode, 1);
                        input_sync(input);
                        input_report_key(input, pdata->keycode, 0);
                        input_sync(input);
                        pm_relax(input->dev.parent);
                } else {
                        mod_timer(&pdata->check_timer,
                                  jiffies + msecs_to_jiffies(DEBOUNCE_TIME));
                }
        }

        /* clear SPO status */
        regmap_write(pdata->snvs, SNVS_LPSR_REG, SNVS_LPSR_SPO);

        return IRQ_HANDLED;
}

static void imx_snvs_pwrkey_act(void *pdata)
{
        struct pwrkey_drv_data *pd = pdata;

        timer_delete_sync(&pd->check_timer);
}

static int imx_snvs_pwrkey_probe(struct platform_device *pdev)
{
        struct pwrkey_drv_data *pdata;
        struct input_dev *input;
        struct device_node *np;
        struct clk *clk;
        int error;
        unsigned int val;
        unsigned int bpt;
        u32 vid;

        /* Get SNVS register Page */
        np = pdev->dev.of_node;
        if (!np)
                return -ENODEV;

        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
        if (!pdata)
                return -ENOMEM;

        pdata->snvs = syscon_regmap_lookup_by_phandle(np, "regmap");
        if (IS_ERR(pdata->snvs)) {
                dev_err(&pdev->dev, "Can't get snvs syscon\n");
                return PTR_ERR(pdata->snvs);
        }

        if (of_property_read_u32(np, "linux,keycode", &pdata->keycode)) {
                pdata->keycode = KEY_POWER;
                dev_warn(&pdev->dev, "KEY_POWER without setting in dts\n");
        }

        clk = devm_clk_get_optional_enabled(&pdev->dev, NULL);
        if (IS_ERR(clk)) {
                dev_err(&pdev->dev, "Failed to get snvs clock (%pe)\n", clk);
                return PTR_ERR(clk);
        }

        pdata->wakeup = of_property_read_bool(np, "wakeup-source");

        pdata->irq = platform_get_irq(pdev, 0);
        if (pdata->irq < 0)
                return -EINVAL;

        error = of_property_read_u32(np, "power-off-time-sec", &val);
        if (!error) {
                switch (val) {
                case 0:
                        bpt = 0x3;
                        break;
                case 5:
                case 10:
                case 15:
                        bpt = (val / 5) - 1;
                        break;
                default:
                        dev_err(&pdev->dev,
                                "power-off-time-sec %d out of range\n", val);
                        return -EINVAL;
                }

                regmap_update_bits(pdata->snvs, SNVS_LPCR_REG, SNVS_LPCR_BPT_MASK,
                                   bpt << SNVS_LPCR_BPT_SHIFT);
        }

        regmap_read(pdata->snvs, SNVS_HPVIDR1_REG, &vid);
        pdata->minor_rev = vid & 0xff;

        regmap_update_bits(pdata->snvs, SNVS_LPCR_REG, SNVS_LPCR_DEP_EN, SNVS_LPCR_DEP_EN);

        /* clear the unexpected interrupt before driver ready */
        regmap_write(pdata->snvs, SNVS_LPSR_REG, SNVS_LPSR_SPO);

        timer_setup(&pdata->check_timer, imx_imx_snvs_check_for_events, 0);

        input = devm_input_allocate_device(&pdev->dev);
        if (!input) {
                dev_err(&pdev->dev, "failed to allocate the input device\n");
                return -ENOMEM;
        }

        input->name = pdev->name;
        input->phys = "snvs-pwrkey/input0";
        input->id.bustype = BUS_HOST;

        input_set_capability(input, EV_KEY, pdata->keycode);

        /* input customer action to cancel release timer */
        error = devm_add_action(&pdev->dev, imx_snvs_pwrkey_act, pdata);
        if (error) {
                dev_err(&pdev->dev, "failed to register remove action\n");
                return error;
        }

        pdata->input = input;
        platform_set_drvdata(pdev, pdata);

        error = devm_request_irq(&pdev->dev, pdata->irq,
                               imx_snvs_pwrkey_interrupt,
                               0, pdev->name, pdev);
        if (error) {
                dev_err(&pdev->dev, "interrupt not available.\n");
                return error;
        }

        error = input_register_device(input);
        if (error < 0) {
                dev_err(&pdev->dev, "failed to register input device\n");
                return error;
        }

        device_init_wakeup(&pdev->dev, pdata->wakeup);
        error = dev_pm_set_wake_irq(&pdev->dev, pdata->irq);
        if (error)
                dev_err(&pdev->dev, "irq wake enable failed.\n");

        return 0;
}

static const struct of_device_id imx_snvs_pwrkey_ids[] = {
        { .compatible = "fsl,sec-v4.0-pwrkey" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx_snvs_pwrkey_ids);

static struct platform_driver imx_snvs_pwrkey_driver = {
        .driver = {
                .name = "snvs_pwrkey",
                .of_match_table = imx_snvs_pwrkey_ids,
        },
        .probe = imx_snvs_pwrkey_probe,
};
module_platform_driver(imx_snvs_pwrkey_driver);

MODULE_AUTHOR("Freescale Semiconductor");
MODULE_DESCRIPTION("i.MX snvs power key Driver");
MODULE_LICENSE("GPL");