lpc32xx-keys.c

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/*
 * NXP LPC32xx SoC Key Scan Interface
 *
 * Authors:
 *    Kevin Wells <[email protected]>
 *    Roland Stigge <[email protected]>
 *
 * Copyright (C) 2010 NXP Semiconductors
 * Copyright (C) 2012 Roland Stigge
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 *
 * 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;
    struct resource *iores;
    void __iomem *kscan_base;
    unsigned int irq;

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

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

    of_property_read_u32(np, "keypad,num-rows", &rows);
    of_property_read_u32(np, "keypad,num-columns", &columns);
    if (!rows || rows != columns) {
        dev_err(dev,
            "rows and columns must be specified and 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 __devinit lpc32xx_kscan_probe(struct platform_device *pdev)
{
    struct lpc32xx_kscan_drv *kscandat;
    struct input_dev *input;
    struct resource *res;
    size_t keymap_size;
    int error;
    int irq;

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res) {
        dev_err(&pdev->dev, "failed to get platform I/O memory\n");
        return -EINVAL;
    }

    irq = platform_get_irq(pdev, 0);
    if (irq < 0 || irq >= NR_IRQS) {
        dev_err(&pdev->dev, "failed to get platform irq\n");
        return -EINVAL;
    }

    kscandat = kzalloc(sizeof(struct lpc32xx_kscan_drv), GFP_KERNEL);
    if (!kscandat) {
        dev_err(&pdev->dev, "failed to allocate memory\n");
        return -ENOMEM;
    }

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

    keymap_size = sizeof(kscandat->keymap[0]) *
                (kscandat->matrix_sz << kscandat->row_shift);
    kscandat->keymap = kzalloc(keymap_size, GFP_KERNEL);
    if (!kscandat->keymap) {
        dev_err(&pdev->dev, "could not allocate memory for keymap\n");
        error = -ENOMEM;
        goto err_free_mem;
    }

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

    /* 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");
        goto err_free_input;
    }

    input_set_drvdata(kscandat->input, kscandat);

    kscandat->iores = request_mem_region(res->start, resource_size(res),
                         pdev->name);
    if (!kscandat->iores) {
        dev_err(&pdev->dev, "failed to request I/O memory\n");
        error = -EBUSY;
        goto err_free_input;
    }

    kscandat->kscan_base = ioremap(kscandat->iores->start,
                       resource_size(kscandat->iores));
    if (!kscandat->kscan_base) {
        dev_err(&pdev->dev, "failed to remap I/O memory\n");
        error = -EBUSY;
        goto err_release_memregion;
    }

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

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

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

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

    platform_set_drvdata(pdev, kscandat);
    return 0;

err_free_irq:
    free_irq(irq, kscandat);
err_clk_put:
    clk_put(kscandat->clk);
err_unmap:
    iounmap(kscandat->kscan_base);
err_release_memregion:
    release_mem_region(kscandat->iores->start,
               resource_size(kscandat->iores));
err_free_input:
    input_free_device(kscandat->input);
err_free_keymap:
    kfree(kscandat->keymap);
err_free_mem:
    kfree(kscandat);

    return error;
}

static int __devexit lpc32xx_kscan_remove(struct platform_device *pdev)
{
    struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);

    free_irq(platform_get_irq(pdev, 0), kscandat);
    clk_put(kscandat->clk);
    iounmap(kscandat->kscan_base);
    release_mem_region(kscandat->iores->start,
               resource_size(kscandat->iores));
    input_unregister_device(kscandat->input);
    kfree(kscandat->keymap);
    kfree(kscandat);

    return 0;
}

#ifdef CONFIG_PM_SLEEP
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;

    mutex_lock(&input->mutex);

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

    mutex_unlock(&input->mutex);
    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 retval = 0;

    mutex_lock(&input->mutex);

    if (input->users) {
        /* Enable clock and clear IRQ */
        retval = clk_prepare_enable(kscandat->clk);
        if (retval == 0)
            writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
    }

    mutex_unlock(&input->mutex);
    return retval;
}
#endif

static 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,
    .remove     = __devexit_p(lpc32xx_kscan_remove),
    .driver     = {
        .name   = DRV_NAME,
        .owner  = THIS_MODULE,
        .pm = &lpc32xx_kscan_pm_ops,
        .of_match_table = of_match_ptr(lpc32xx_kscan_match),
    }
};

module_platform_driver(lpc32xx_kscan_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Kevin Wells <[email protected]>");
MODULE_AUTHOR("Roland Stigge <[email protected]>");
MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");