navpoint.c

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/*
 * Synaptics NavPoint (PXA27x SSP/SPI) driver.
 *
 * Copyright (C) 2012 Paul Parsons <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/input.h>
#include <linux/input/navpoint.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/pxa2xx_ssp.h>
#include <linux/slab.h>

/*
 * Synaptics Modular Embedded Protocol: Module Packet Format.
 * Module header byte 2:0 = Length (# bytes that follow)
 * Module header byte 4:3 = Control
 * Module header byte 7:5 = Module Address
 */
#define HEADER_LENGTH(byte) ((byte) & 0x07)
#define HEADER_CONTROL(byte)    (((byte) >> 3) & 0x03)
#define HEADER_ADDRESS(byte)    ((byte) >> 5)

struct navpoint {
    struct ssp_device   *ssp;
    struct input_dev    *input;
    struct device       *dev;
    int         gpio;
    int         index;
    u8          data[1 + HEADER_LENGTH(0xff)];
};

/*
 * Initialization values for SSCR0_x, SSCR1_x, SSSR_x.
 */
static const u32 sscr0 = 0
    | SSCR0_TUM     /* TIM = 1; No TUR interrupts */
    | SSCR0_RIM     /* RIM = 1; No ROR interrupts */
    | SSCR0_SSE     /* SSE = 1; SSP enabled */
    | SSCR0_Motorola    /* FRF = 0; Motorola SPI */
    | SSCR0_DataSize(16)    /* DSS = 15; Data size = 16-bit */
    ;
static const u32 sscr1 = 0
    | SSCR1_SCFR        /* SCFR = 1; SSPSCLK only during transfers */
    | SSCR1_SCLKDIR     /* SCLKDIR = 1; Slave mode */
    | SSCR1_SFRMDIR     /* SFRMDIR = 1; Slave mode */
    | SSCR1_RWOT        /* RWOT = 1; Receive without transmit mode */
    | SSCR1_RxTresh(1)  /* RFT = 0; Receive FIFO threshold = 1 */
    | SSCR1_SPH     /* SPH = 1; SSPSCLK inactive 0.5 + 1 cycles */
    | SSCR1_RIE     /* RIE = 1; Receive FIFO interrupt enabled */
    ;
static const u32 sssr = 0
    | SSSR_BCE      /* BCE = 1; Clear BCE */
    | SSSR_TUR      /* TUR = 1; Clear TUR */
    | SSSR_EOC      /* EOC = 1; Clear EOC */
    | SSSR_TINT     /* TINT = 1; Clear TINT */
    | SSSR_PINT     /* PINT = 1; Clear PINT */
    | SSSR_ROR      /* ROR = 1; Clear ROR */
    ;

/*
 * MEP Query $22: Touchpad Coordinate Range Query is not supported by
 * the NavPoint module, so sampled values provide the default limits.
 */
#define NAVPOINT_X_MIN      1278
#define NAVPOINT_X_MAX      5340
#define NAVPOINT_Y_MIN      1572
#define NAVPOINT_Y_MAX      4396
#define NAVPOINT_PRESSURE_MIN   0
#define NAVPOINT_PRESSURE_MAX   255

static void navpoint_packet(struct navpoint *navpoint)
{
    int finger;
    int gesture;
    int x, y, z;

    switch (navpoint->data[0]) {
    case 0xff:  /* Garbage (packet?) between reset and Hello packet */
    case 0x00:  /* Module 0, NULL packet */
        break;

    case 0x0e:  /* Module 0, Absolute packet */
        finger = (navpoint->data[1] & 0x01);
        gesture = (navpoint->data[1] & 0x02);
        x = ((navpoint->data[2] & 0x1f) << 8) | navpoint->data[3];
        y = ((navpoint->data[4] & 0x1f) << 8) | navpoint->data[5];
        z = navpoint->data[6];
        input_report_key(navpoint->input, BTN_TOUCH, finger);
        input_report_abs(navpoint->input, ABS_X, x);
        input_report_abs(navpoint->input, ABS_Y, y);
        input_report_abs(navpoint->input, ABS_PRESSURE, z);
        input_report_key(navpoint->input, BTN_TOOL_FINGER, finger);
        input_report_key(navpoint->input, BTN_LEFT, gesture);
        input_sync(navpoint->input);
        break;

    case 0x19:  /* Module 0, Hello packet */
        if ((navpoint->data[1] & 0xf0) == 0x10)
            break;
        /* FALLTHROUGH */
    default:
        dev_warn(navpoint->dev,
             "spurious packet: data=0x%02x,0x%02x,...\n",
             navpoint->data[0], navpoint->data[1]);
        break;
    }
}

static irqreturn_t navpoint_irq(int irq, void *dev_id)
{
    struct navpoint *navpoint = dev_id;
    struct ssp_device *ssp = navpoint->ssp;
    irqreturn_t ret = IRQ_NONE;
    u32 status;

    status = pxa_ssp_read_reg(ssp, SSSR);
    if (status & sssr) {
        dev_warn(navpoint->dev,
             "unexpected interrupt: status=0x%08x\n", status);
        pxa_ssp_write_reg(ssp, SSSR, (status & sssr));
        ret = IRQ_HANDLED;
    }

    while (status & SSSR_RNE) {
        u32 data;

        data = pxa_ssp_read_reg(ssp, SSDR);
        navpoint->data[navpoint->index + 0] = (data >> 8);
        navpoint->data[navpoint->index + 1] = data;
        navpoint->index += 2;
        if (HEADER_LENGTH(navpoint->data[0]) < navpoint->index) {
            navpoint_packet(navpoint);
            navpoint->index = 0;
        }
        status = pxa_ssp_read_reg(ssp, SSSR);
        ret = IRQ_HANDLED;
    }

    return ret;
}

static void navpoint_up(struct navpoint *navpoint)
{
    struct ssp_device *ssp = navpoint->ssp;
    int timeout;

    clk_prepare_enable(ssp->clk);

    pxa_ssp_write_reg(ssp, SSCR1, sscr1);
    pxa_ssp_write_reg(ssp, SSSR, sssr);
    pxa_ssp_write_reg(ssp, SSTO, 0);
    pxa_ssp_write_reg(ssp, SSCR0, sscr0);   /* SSCR0_SSE written last */

    /* Wait until SSP port is ready for slave clock operations */
    for (timeout = 100; timeout != 0; --timeout) {
        if (!(pxa_ssp_read_reg(ssp, SSSR) & SSSR_CSS))
            break;
        msleep(1);
    }

    if (timeout == 0)
        dev_err(navpoint->dev,
            "timeout waiting for SSSR[CSS] to clear\n");

    if (gpio_is_valid(navpoint->gpio))
        gpio_set_value(navpoint->gpio, 1);
}

static void navpoint_down(struct navpoint *navpoint)
{
    struct ssp_device *ssp = navpoint->ssp;

    if (gpio_is_valid(navpoint->gpio))
        gpio_set_value(navpoint->gpio, 0);

    pxa_ssp_write_reg(ssp, SSCR0, 0);

    clk_disable_unprepare(ssp->clk);
}

static int navpoint_open(struct input_dev *input)
{
    struct navpoint *navpoint = input_get_drvdata(input);

    navpoint_up(navpoint);

    return 0;
}

static void navpoint_close(struct input_dev *input)
{
    struct navpoint *navpoint = input_get_drvdata(input);

    navpoint_down(navpoint);
}

static int __devinit navpoint_probe(struct platform_device *pdev)
{
    const struct navpoint_platform_data *pdata =
                    dev_get_platdata(&pdev->dev);
    struct ssp_device *ssp;
    struct input_dev *input;
    struct navpoint *navpoint;
    int error;

    if (!pdata) {
        dev_err(&pdev->dev, "no platform data\n");
        return -EINVAL;
    }

    if (gpio_is_valid(pdata->gpio)) {
        error = gpio_request_one(pdata->gpio, GPIOF_OUT_INIT_LOW,
                     "SYNAPTICS_ON");
        if (error)
            return error;
    }

    ssp = pxa_ssp_request(pdata->port, pdev->name);
    if (!ssp) {
        error = -ENODEV;
        goto err_free_gpio;
    }

    /* HaRET does not disable devices before jumping into Linux */
    if (pxa_ssp_read_reg(ssp, SSCR0) & SSCR0_SSE) {
        pxa_ssp_write_reg(ssp, SSCR0, 0);
        dev_warn(&pdev->dev, "ssp%d already enabled\n", pdata->port);
    }

    navpoint = kzalloc(sizeof(*navpoint), GFP_KERNEL);
    input = input_allocate_device();
    if (!navpoint || !input) {
        error = -ENOMEM;
        goto err_free_mem;
    }

    navpoint->ssp = ssp;
    navpoint->input = input;
    navpoint->dev = &pdev->dev;
    navpoint->gpio = pdata->gpio;

    input->name = pdev->name;
    input->dev.parent = &pdev->dev;

    __set_bit(EV_KEY, input->evbit);
    __set_bit(EV_ABS, input->evbit);
    __set_bit(BTN_LEFT, input->keybit);
    __set_bit(BTN_TOUCH, input->keybit);
    __set_bit(BTN_TOOL_FINGER, input->keybit);

    input_set_abs_params(input, ABS_X,
                 NAVPOINT_X_MIN, NAVPOINT_X_MAX, 0, 0);
    input_set_abs_params(input, ABS_Y,
                 NAVPOINT_Y_MIN, NAVPOINT_Y_MAX, 0, 0);
    input_set_abs_params(input, ABS_PRESSURE,
                 NAVPOINT_PRESSURE_MIN, NAVPOINT_PRESSURE_MAX,
                 0, 0);

    input->open = navpoint_open;
    input->close = navpoint_close;

    input_set_drvdata(input, navpoint);

    error = request_irq(ssp->irq, navpoint_irq, 0, pdev->name, navpoint);
    if (error)
        goto err_free_mem;

    error = input_register_device(input);
    if (error)
        goto err_free_irq;

    platform_set_drvdata(pdev, navpoint);
    dev_dbg(&pdev->dev, "ssp%d, irq %d\n", pdata->port, ssp->irq);

    return 0;

err_free_irq:
    free_irq(ssp->irq, &pdev->dev);
err_free_mem:
    input_free_device(input);
    kfree(navpoint);
    pxa_ssp_free(ssp);
err_free_gpio:
    if (gpio_is_valid(pdata->gpio))
        gpio_free(pdata->gpio);

    return error;
}

static int __devexit navpoint_remove(struct platform_device *pdev)
{
    const struct navpoint_platform_data *pdata =
                    dev_get_platdata(&pdev->dev);
    struct navpoint *navpoint = platform_get_drvdata(pdev);
    struct ssp_device *ssp = navpoint->ssp;

    free_irq(ssp->irq, navpoint);

    input_unregister_device(navpoint->input);
    kfree(navpoint);

    pxa_ssp_free(ssp);

    if (gpio_is_valid(pdata->gpio))
        gpio_free(pdata->gpio);

    return 0;
}

#ifdef CONFIG_PM_SLEEP
static int navpoint_suspend(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct navpoint *navpoint = platform_get_drvdata(pdev);
    struct input_dev *input = navpoint->input;

    mutex_lock(&input->mutex);
    if (input->users)
        navpoint_down(navpoint);
    mutex_unlock(&input->mutex);

    return 0;
}

static int navpoint_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct navpoint *navpoint = platform_get_drvdata(pdev);
    struct input_dev *input = navpoint->input;

    mutex_lock(&input->mutex);
    if (input->users)
        navpoint_up(navpoint);
    mutex_unlock(&input->mutex);

    return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(navpoint_pm_ops, navpoint_suspend, navpoint_resume);

static struct platform_driver navpoint_driver = {
    .probe      = navpoint_probe,
    .remove     = __devexit_p(navpoint_remove),
    .driver = {
        .name   = "navpoint",
        .owner  = THIS_MODULE,
        .pm = &navpoint_pm_ops,
    },
};

module_platform_driver(navpoint_driver);

MODULE_AUTHOR("Paul Parsons <[email protected]>");
MODULE_DESCRIPTION("Synaptics NavPoint (PXA27x SSP/SPI) driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:navpoint");