// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * NXP LPC32xx SoC Key Scan Interface
 *
 * Authors:
 *    Kevin Wells <kevin.wells@nxp.com>
 *    Roland Stigge <stigge@antcom.de>
 *
 * Copyright (C) 2010 NXP Semiconductors
 * Copyright (C) 2012 Roland Stigge
 *
 * This controller supports square key matrices from 1x1 up to 8x8
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/irq.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/input/matrix_keypad.h>

#define DRV_NAME                                "lpc32xx_keys"

/*
 * Key scanner register offsets
 */
#define LPC32XX_KS_DEB(x)                       ((x) + 0x00)
#define LPC32XX_KS_STATE_COND(x)                ((x) + 0x04)
#define LPC32XX_KS_IRQ(x)                       ((x) + 0x08)
#define LPC32XX_KS_SCAN_CTL(x)                  ((x) + 0x0C)
#define LPC32XX_KS_FAST_TST(x)                  ((x) + 0x10)
#define LPC32XX_KS_MATRIX_DIM(x)                ((x) + 0x14) /* 1..8 */
#define LPC32XX_KS_DATA(x, y)                   ((x) + 0x40 + ((y) << 2))

#define LPC32XX_KSCAN_DEB_NUM_DEB_PASS(n)       ((n) & 0xFF)

#define LPC32XX_KSCAN_SCOND_IN_IDLE             0x0
#define LPC32XX_KSCAN_SCOND_IN_SCANONCE         0x1
#define LPC32XX_KSCAN_SCOND_IN_IRQGEN           0x2
#define LPC32XX_KSCAN_SCOND_IN_SCAN_MATRIX      0x3

#define LPC32XX_KSCAN_IRQ_PENDING_CLR           0x1

#define LPC32XX_KSCAN_SCTRL_SCAN_DELAY(n)       ((n) & 0xFF)

#define LPC32XX_KSCAN_FTST_FORCESCANONCE        0x1
#define LPC32XX_KSCAN_FTST_USE32K_CLK           0x2

#define LPC32XX_KSCAN_MSEL_SELECT(n)            ((n) & 0xF)

struct lpc32xx_kscan_drv {
        struct input_dev *input;
        struct clk *clk;
        void __iomem *kscan_base;

        u32 matrix_sz;          /* Size of matrix in XxY, ie. 3 = 3x3 */
        u32 deb_clks;           /* Debounce clocks (based on 32KHz clock) */
        u32 scan_delay;         /* Scan delay (based on 32KHz clock) */

        unsigned int row_shift;
        unsigned short *keymap; /* Pointer to key map for the scan matrix */

        u8 lastkeystates[8];
};

static void lpc32xx_mod_states(struct lpc32xx_kscan_drv *kscandat, int col)
{
        struct input_dev *input = kscandat->input;
        unsigned row, changed, scancode, keycode;
        u8 key;

        key = readl(LPC32XX_KS_DATA(kscandat->kscan_base, col));
        changed = key ^ kscandat->lastkeystates[col];
        kscandat->lastkeystates[col] = key;

        for (row = 0; changed; row++, changed >>= 1) {
                if (changed & 1) {
                        /* Key state changed, signal an event */
                        scancode = MATRIX_SCAN_CODE(row, col,
                                                    kscandat->row_shift);
                        keycode = kscandat->keymap[scancode];
                        input_event(input, EV_MSC, MSC_SCAN, scancode);
                        input_report_key(input, keycode, key & (1 << row));
                }
        }
}

static irqreturn_t lpc32xx_kscan_irq(int irq, void *dev_id)
{
        struct lpc32xx_kscan_drv *kscandat = dev_id;
        int i;

        for (i = 0; i < kscandat->matrix_sz; i++)
                lpc32xx_mod_states(kscandat, i);

        writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));

        input_sync(kscandat->input);

        return IRQ_HANDLED;
}

static int lpc32xx_kscan_open(struct input_dev *dev)
{
        struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
        int error;

        error = clk_prepare_enable(kscandat->clk);
        if (error)
                return error;

        writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));

        return 0;
}

static void lpc32xx_kscan_close(struct input_dev *dev)
{
        struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);

        writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
        clk_disable_unprepare(kscandat->clk);
}

static int lpc32xx_parse_dt(struct device *dev,
                                      struct lpc32xx_kscan_drv *kscandat)
{
        struct device_node *np = dev->of_node;
        u32 rows = 0, columns = 0;
        int err;

        err = matrix_keypad_parse_properties(dev, &rows, &columns);
        if (err)
                return err;
        if (rows != columns) {
                dev_err(dev, "rows and columns must be equal!\n");
                return -EINVAL;
        }

        kscandat->matrix_sz = rows;
        kscandat->row_shift = get_count_order(columns);

        of_property_read_u32(np, "nxp,debounce-delay-ms", &kscandat->deb_clks);
        of_property_read_u32(np, "nxp,scan-delay-ms", &kscandat->scan_delay);
        if (!kscandat->deb_clks || !kscandat->scan_delay) {
                dev_err(dev, "debounce or scan delay not specified\n");
                return -EINVAL;
        }

        return 0;
}

static int lpc32xx_kscan_probe(struct platform_device *pdev)
{
        struct lpc32xx_kscan_drv *kscandat;
        struct input_dev *input;
        size_t keymap_size;
        int error;
        int irq;

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

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

        error = lpc32xx_parse_dt(&pdev->dev, kscandat);
        if (error) {
                dev_err(&pdev->dev, "failed to parse device tree\n");
                return error;
        }

        keymap_size = sizeof(kscandat->keymap[0]) *
                                (kscandat->matrix_sz << kscandat->row_shift);
        kscandat->keymap = devm_kzalloc(&pdev->dev, keymap_size, GFP_KERNEL);
        if (!kscandat->keymap)
                return -ENOMEM;

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

        /* Setup key input */
        input->name             = pdev->name;
        input->phys             = "lpc32xx/input0";
        input->id.vendor        = 0x0001;
        input->id.product       = 0x0001;
        input->id.version       = 0x0100;
        input->open             = lpc32xx_kscan_open;
        input->close            = lpc32xx_kscan_close;
        input->dev.parent       = &pdev->dev;

        input_set_capability(input, EV_MSC, MSC_SCAN);

        error = matrix_keypad_build_keymap(NULL, NULL,
                                           kscandat->matrix_sz,
                                           kscandat->matrix_sz,
                                           kscandat->keymap, kscandat->input);
        if (error) {
                dev_err(&pdev->dev, "failed to build keymap\n");
                return error;
        }

        input_set_drvdata(kscandat->input, kscandat);

        kscandat->kscan_base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(kscandat->kscan_base))
                return PTR_ERR(kscandat->kscan_base);

        /* Get the key scanner clock */
        kscandat->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(kscandat->clk)) {
                dev_err(&pdev->dev, "failed to get clock\n");
                return PTR_ERR(kscandat->clk);
        }

        /* Configure the key scanner */
        error = clk_prepare_enable(kscandat->clk);
        if (error)
                return error;

        writel(kscandat->deb_clks, LPC32XX_KS_DEB(kscandat->kscan_base));
        writel(kscandat->scan_delay, LPC32XX_KS_SCAN_CTL(kscandat->kscan_base));
        writel(LPC32XX_KSCAN_FTST_USE32K_CLK,
               LPC32XX_KS_FAST_TST(kscandat->kscan_base));
        writel(kscandat->matrix_sz,
               LPC32XX_KS_MATRIX_DIM(kscandat->kscan_base));
        writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
        clk_disable_unprepare(kscandat->clk);

        error = devm_request_irq(&pdev->dev, irq, lpc32xx_kscan_irq, 0,
                                 pdev->name, kscandat);
        if (error) {
                dev_err(&pdev->dev, "failed to request irq\n");
                return error;
        }

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

        platform_set_drvdata(pdev, kscandat);

        return 0;
}

static int lpc32xx_kscan_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
        struct input_dev *input = kscandat->input;

        guard(mutex)(&input->mutex);

        if (input_device_enabled(input)) {
                /* Clear IRQ and disable clock */
                writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
                clk_disable_unprepare(kscandat->clk);
        }

        return 0;
}

static int lpc32xx_kscan_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
        struct input_dev *input = kscandat->input;
        int error;

        guard(mutex)(&input->mutex);

        if (input_device_enabled(input)) {
                /* Enable clock and clear IRQ */
                error = clk_prepare_enable(kscandat->clk);
                if (error)
                        return error;

                writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
        }

        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
                                lpc32xx_kscan_resume);

static const struct of_device_id lpc32xx_kscan_match[] = {
        { .compatible = "nxp,lpc3220-key" },
        {},
};
MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);

static struct platform_driver lpc32xx_kscan_driver = {
        .probe          = lpc32xx_kscan_probe,
        .driver         = {
                .name   = DRV_NAME,
                .pm     = pm_sleep_ptr(&lpc32xx_kscan_pm_ops),
                .of_match_table = lpc32xx_kscan_match,
        }
};

module_platform_driver(lpc32xx_kscan_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");