spear-keyboard.c

Go to the documentation of this file.

/*
 * SPEAr Keyboard Driver
 * Based on omap-keypad driver
 *
 * Copyright (C) 2010 ST Microelectronics
 * Rajeev Kumar<[email protected]>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_wakeup.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/platform_data/keyboard-spear.h>

/* Keyboard Registers */
#define MODE_CTL_REG    0x00
#define STATUS_REG  0x0C
#define DATA_REG    0x10
#define INTR_MASK   0x54

/* Register Values */
#define NUM_ROWS    16
#define NUM_COLS    16
#define MODE_CTL_PCLK_FREQ_SHIFT    9
#define MODE_CTL_PCLK_FREQ_MSK      0x7F

#define MODE_CTL_KEYBOARD   (0x2 << 0)
#define MODE_CTL_SCAN_RATE_10   (0x0 << 2)
#define MODE_CTL_SCAN_RATE_20   (0x1 << 2)
#define MODE_CTL_SCAN_RATE_40   (0x2 << 2)
#define MODE_CTL_SCAN_RATE_80   (0x3 << 2)
#define MODE_CTL_KEYNUM_SHIFT   6
#define MODE_CTL_START_SCAN (0x1 << 8)

#define STATUS_DATA_AVAIL   (0x1 << 1)

#define DATA_ROW_MASK       0xF0
#define DATA_COLUMN_MASK    0x0F

#define ROW_SHIFT       4

struct spear_kbd {
    struct input_dev *input;
    struct resource *res;
    void __iomem *io_base;
    struct clk *clk;
    unsigned int irq;
    unsigned int mode;
    unsigned short last_key;
    unsigned short keycodes[NUM_ROWS * NUM_COLS];
    bool rep;
    unsigned int suspended_rate;
    u32 mode_ctl_reg;
};

static irqreturn_t spear_kbd_interrupt(int irq, void *dev_id)
{
    struct spear_kbd *kbd = dev_id;
    struct input_dev *input = kbd->input;
    unsigned int key;
    u32 sts, val;

    sts = readl_relaxed(kbd->io_base + STATUS_REG);
    if (!(sts & STATUS_DATA_AVAIL))
        return IRQ_NONE;

    if (kbd->last_key != KEY_RESERVED) {
        input_report_key(input, kbd->last_key, 0);
        kbd->last_key = KEY_RESERVED;
    }

    /* following reads active (row, col) pair */
    val = readl_relaxed(kbd->io_base + DATA_REG) &
        (DATA_ROW_MASK | DATA_COLUMN_MASK);
    key = kbd->keycodes[val];

    input_event(input, EV_MSC, MSC_SCAN, val);
    input_report_key(input, key, 1);
    input_sync(input);

    kbd->last_key = key;

    /* clear interrupt */
    writel_relaxed(0, kbd->io_base + STATUS_REG);

    return IRQ_HANDLED;
}

static int spear_kbd_open(struct input_dev *dev)
{
    struct spear_kbd *kbd = input_get_drvdata(dev);
    int error;
    u32 val;

    kbd->last_key = KEY_RESERVED;

    error = clk_enable(kbd->clk);
    if (error)
        return error;

    /* keyboard rate to be programmed is input clock (in MHz) - 1 */
    val = clk_get_rate(kbd->clk) / 1000000 - 1;
    val = (val & MODE_CTL_PCLK_FREQ_MSK) << MODE_CTL_PCLK_FREQ_SHIFT;

    /* program keyboard */
    val = MODE_CTL_SCAN_RATE_80 | MODE_CTL_KEYBOARD | val |
        (kbd->mode << MODE_CTL_KEYNUM_SHIFT);
    writel_relaxed(val, kbd->io_base + MODE_CTL_REG);
    writel_relaxed(1, kbd->io_base + STATUS_REG);

    /* start key scan */
    val = readl_relaxed(kbd->io_base + MODE_CTL_REG);
    val |= MODE_CTL_START_SCAN;
    writel_relaxed(val, kbd->io_base + MODE_CTL_REG);

    return 0;
}

static void spear_kbd_close(struct input_dev *dev)
{
    struct spear_kbd *kbd = input_get_drvdata(dev);
    u32 val;

    /* stop key scan */
    val = readl_relaxed(kbd->io_base + MODE_CTL_REG);
    val &= ~MODE_CTL_START_SCAN;
    writel_relaxed(val, kbd->io_base + MODE_CTL_REG);

    clk_disable(kbd->clk);

    kbd->last_key = KEY_RESERVED;
}

#ifdef CONFIG_OF
static int __devinit spear_kbd_parse_dt(struct platform_device *pdev,
                                        struct spear_kbd *kbd)
{
    struct device_node *np = pdev->dev.of_node;
    int error;
    u32 val, suspended_rate;

    if (!np) {
        dev_err(&pdev->dev, "Missing DT data\n");
        return -EINVAL;
    }

    if (of_property_read_bool(np, "autorepeat"))
        kbd->rep = true;

    if (of_property_read_u32(np, "suspended_rate", &suspended_rate))
        kbd->suspended_rate = suspended_rate;

    error = of_property_read_u32(np, "st,mode", &val);
    if (error) {
        dev_err(&pdev->dev, "DT: Invalid or missing mode\n");
        return error;
    }

    kbd->mode = val;
    return 0;
}
#else
static inline int spear_kbd_parse_dt(struct platform_device *pdev,
                     struct spear_kbd *kbd)
{
    return -ENOSYS;
}
#endif

static int __devinit spear_kbd_probe(struct platform_device *pdev)
{
    struct kbd_platform_data *pdata = dev_get_platdata(&pdev->dev);
    const struct matrix_keymap_data *keymap = pdata ? pdata->keymap : NULL;
    struct spear_kbd *kbd;
    struct input_dev *input_dev;
    struct resource *res;
    int irq;
    int error;

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res) {
        dev_err(&pdev->dev, "no keyboard resource defined\n");
        return -EBUSY;
    }

    irq = platform_get_irq(pdev, 0);
    if (irq < 0) {
        dev_err(&pdev->dev, "not able to get irq for the device\n");
        return irq;
    }

    kbd = kzalloc(sizeof(*kbd), GFP_KERNEL);
    input_dev = input_allocate_device();
    if (!kbd || !input_dev) {
        dev_err(&pdev->dev, "out of memory\n");
        error = -ENOMEM;
        goto err_free_mem;
    }

    kbd->input = input_dev;
    kbd->irq = irq;

    if (!pdata) {
        error = spear_kbd_parse_dt(pdev, kbd);
        if (error)
            goto err_free_mem;
    } else {
        kbd->mode = pdata->mode;
        kbd->rep = pdata->rep;
        kbd->suspended_rate = pdata->suspended_rate;
    }

    kbd->res = request_mem_region(res->start, resource_size(res),
                      pdev->name);
    if (!kbd->res) {
        dev_err(&pdev->dev, "keyboard region already claimed\n");
        error = -EBUSY;
        goto err_free_mem;
    }

    kbd->io_base = ioremap(res->start, resource_size(res));
    if (!kbd->io_base) {
        dev_err(&pdev->dev, "ioremap failed for kbd_region\n");
        error = -ENOMEM;
        goto err_release_mem_region;
    }

    kbd->clk = clk_get(&pdev->dev, NULL);
    if (IS_ERR(kbd->clk)) {
        error = PTR_ERR(kbd->clk);
        goto err_iounmap;
    }

    input_dev->name = "Spear Keyboard";
    input_dev->phys = "keyboard/input0";
    input_dev->dev.parent = &pdev->dev;
    input_dev->id.bustype = BUS_HOST;
    input_dev->id.vendor = 0x0001;
    input_dev->id.product = 0x0001;
    input_dev->id.version = 0x0100;
    input_dev->open = spear_kbd_open;
    input_dev->close = spear_kbd_close;

    error = matrix_keypad_build_keymap(keymap, NULL, NUM_ROWS, NUM_COLS,
                       kbd->keycodes, input_dev);
    if (error) {
        dev_err(&pdev->dev, "Failed to build keymap\n");
        goto err_put_clk;
    }

    if (kbd->rep)
        __set_bit(EV_REP, input_dev->evbit);
    input_set_capability(input_dev, EV_MSC, MSC_SCAN);

    input_set_drvdata(input_dev, kbd);

    error = request_irq(irq, spear_kbd_interrupt, 0, "keyboard", kbd);
    if (error) {
        dev_err(&pdev->dev, "request_irq fail\n");
        goto err_put_clk;
    }

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

    device_init_wakeup(&pdev->dev, 1);
    platform_set_drvdata(pdev, kbd);

    return 0;

err_free_irq:
    free_irq(kbd->irq, kbd);
err_put_clk:
    clk_put(kbd->clk);
err_iounmap:
    iounmap(kbd->io_base);
err_release_mem_region:
    release_mem_region(res->start, resource_size(res));
err_free_mem:
    input_free_device(input_dev);
    kfree(kbd);

    return error;
}

static int __devexit spear_kbd_remove(struct platform_device *pdev)
{
    struct spear_kbd *kbd = platform_get_drvdata(pdev);

    free_irq(kbd->irq, kbd);
    input_unregister_device(kbd->input);
    clk_put(kbd->clk);
    iounmap(kbd->io_base);
    release_mem_region(kbd->res->start, resource_size(kbd->res));
    kfree(kbd);

    device_init_wakeup(&pdev->dev, 0);
    platform_set_drvdata(pdev, NULL);

    return 0;
}

#ifdef CONFIG_PM
static int spear_kbd_suspend(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct spear_kbd *kbd = platform_get_drvdata(pdev);
    struct input_dev *input_dev = kbd->input;
    unsigned int rate = 0, mode_ctl_reg, val;

    mutex_lock(&input_dev->mutex);

    /* explicitly enable clock as we may program device */
    clk_enable(kbd->clk);

    mode_ctl_reg = readl_relaxed(kbd->io_base + MODE_CTL_REG);

    if (device_may_wakeup(&pdev->dev)) {
        enable_irq_wake(kbd->irq);

        /*
         * reprogram the keyboard operating frequency as on some
         * platform it may change during system suspended
         */
        if (kbd->suspended_rate)
            rate = kbd->suspended_rate / 1000000 - 1;
        else
            rate = clk_get_rate(kbd->clk) / 1000000 - 1;

        val = mode_ctl_reg &
            ~(MODE_CTL_PCLK_FREQ_MSK << MODE_CTL_PCLK_FREQ_SHIFT);
        val |= (rate & MODE_CTL_PCLK_FREQ_MSK)
            << MODE_CTL_PCLK_FREQ_SHIFT;
        writel_relaxed(val, kbd->io_base + MODE_CTL_REG);

    } else {
        if (input_dev->users) {
            writel_relaxed(mode_ctl_reg & ~MODE_CTL_START_SCAN,
                    kbd->io_base + MODE_CTL_REG);
            clk_disable(kbd->clk);
        }
    }

    /* store current configuration */
    if (input_dev->users)
        kbd->mode_ctl_reg = mode_ctl_reg;

    /* restore previous clk state */
    clk_disable(kbd->clk);

    mutex_unlock(&input_dev->mutex);

    return 0;
}

static int spear_kbd_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct spear_kbd *kbd = platform_get_drvdata(pdev);
    struct input_dev *input_dev = kbd->input;

    mutex_lock(&input_dev->mutex);

    if (device_may_wakeup(&pdev->dev)) {
        disable_irq_wake(kbd->irq);
    } else {
        if (input_dev->users)
            clk_enable(kbd->clk);
    }

    /* restore current configuration */
    if (input_dev->users)
        writel_relaxed(kbd->mode_ctl_reg, kbd->io_base + MODE_CTL_REG);

    mutex_unlock(&input_dev->mutex);

    return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(spear_kbd_pm_ops, spear_kbd_suspend, spear_kbd_resume);

#ifdef CONFIG_OF
static const struct of_device_id spear_kbd_id_table[] = {
    { .compatible = "st,spear300-kbd" },
    {}
};
MODULE_DEVICE_TABLE(of, spear_kbd_id_table);
#endif

static struct platform_driver spear_kbd_driver = {
    .probe      = spear_kbd_probe,
    .remove     = __devexit_p(spear_kbd_remove),
    .driver     = {
        .name   = "keyboard",
        .owner  = THIS_MODULE,
        .pm = &spear_kbd_pm_ops,
        .of_match_table = of_match_ptr(spear_kbd_id_table),
    },
};
module_platform_driver(spear_kbd_driver);

MODULE_AUTHOR("Rajeev Kumar");
MODULE_DESCRIPTION("SPEAr Keyboard Driver");
MODULE_LICENSE("GPL");