mmp-driver.c

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/*
 * Support for the camera device found on Marvell MMP processors; known
 * to work with the Armada 610 as used in the OLPC 1.75 system.
 *
 * Copyright 2011 Jonathan Corbet <[email protected]>
 *
 * This file may be distributed under the terms of the GNU General
 * Public License, version 2.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/i2c-gpio.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/videodev2.h>
#include <media/v4l2-device.h>
#include <media/v4l2-chip-ident.h>
#include <media/mmp-camera.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/list.h>
#include <linux/pm.h>

#include "mcam-core.h"

MODULE_ALIAS("platform:mmp-camera");
MODULE_AUTHOR("Jonathan Corbet <[email protected]>");
MODULE_LICENSE("GPL");

struct mmp_camera {
    void *power_regs;
    struct platform_device *pdev;
    struct mcam_camera mcam;
    struct list_head devlist;
    int irq;
};

static inline struct mmp_camera *mcam_to_cam(struct mcam_camera *mcam)
{
    return container_of(mcam, struct mmp_camera, mcam);
}

/*
 * A silly little infrastructure so we can keep track of our devices.
 * Chances are that we will never have more than one of them, but
 * the Armada 610 *does* have two controllers...
 */

static LIST_HEAD(mmpcam_devices);
static struct mutex mmpcam_devices_lock;

static void mmpcam_add_device(struct mmp_camera *cam)
{
    mutex_lock(&mmpcam_devices_lock);
    list_add(&cam->devlist, &mmpcam_devices);
    mutex_unlock(&mmpcam_devices_lock);
}

static void mmpcam_remove_device(struct mmp_camera *cam)
{
    mutex_lock(&mmpcam_devices_lock);
    list_del(&cam->devlist);
    mutex_unlock(&mmpcam_devices_lock);
}

/*
 * Platform dev remove passes us a platform_device, and there's
 * no handy unused drvdata to stash a backpointer in.  So just
 * dig it out of our list.
 */
static struct mmp_camera *mmpcam_find_device(struct platform_device *pdev)
{
    struct mmp_camera *cam;

    mutex_lock(&mmpcam_devices_lock);
    list_for_each_entry(cam, &mmpcam_devices, devlist) {
        if (cam->pdev == pdev) {
            mutex_unlock(&mmpcam_devices_lock);
            return cam;
        }
    }
    mutex_unlock(&mmpcam_devices_lock);
    return NULL;
}




/*
 * Power-related registers; this almost certainly belongs
 * somewhere else.
 *
 * ARMADA 610 register manual, sec 7.2.1, p1842.
 */
#define CPU_SUBSYS_PMU_BASE 0xd4282800
#define REG_CCIC_DCGCR      0x28    /* CCIC dyn clock gate ctrl reg */
#define REG_CCIC_CRCR       0x50    /* CCIC clk reset ctrl reg  */

/*
 * Power control.
 */
static void mmpcam_power_up_ctlr(struct mmp_camera *cam)
{
    iowrite32(0x3f, cam->power_regs + REG_CCIC_DCGCR);
    iowrite32(0x3805b, cam->power_regs + REG_CCIC_CRCR);
    mdelay(1);
}

static void mmpcam_power_up(struct mcam_camera *mcam)
{
    struct mmp_camera *cam = mcam_to_cam(mcam);
    struct mmp_camera_platform_data *pdata;
/*
 * Turn on power and clocks to the controller.
 */
    mmpcam_power_up_ctlr(cam);
/*
 * Provide power to the sensor.
 */
    mcam_reg_write(mcam, REG_CLKCTRL, 0x60000002);
    pdata = cam->pdev->dev.platform_data;
    gpio_set_value(pdata->sensor_power_gpio, 1);
    mdelay(5);
    mcam_reg_clear_bit(mcam, REG_CTRL1, 0x10000000);
    gpio_set_value(pdata->sensor_reset_gpio, 0); /* reset is active low */
    mdelay(5);
    gpio_set_value(pdata->sensor_reset_gpio, 1); /* reset is active low */
    mdelay(5);
}

static void mmpcam_power_down(struct mcam_camera *mcam)
{
    struct mmp_camera *cam = mcam_to_cam(mcam);
    struct mmp_camera_platform_data *pdata;
/*
 * Turn off clocks and set reset lines
 */
    iowrite32(0, cam->power_regs + REG_CCIC_DCGCR);
    iowrite32(0, cam->power_regs + REG_CCIC_CRCR);
/*
 * Shut down the sensor.
 */
    pdata = cam->pdev->dev.platform_data;
    gpio_set_value(pdata->sensor_power_gpio, 0);
    gpio_set_value(pdata->sensor_reset_gpio, 0);
}


static irqreturn_t mmpcam_irq(int irq, void *data)
{
    struct mcam_camera *mcam = data;
    unsigned int irqs, handled;

    spin_lock(&mcam->dev_lock);
    irqs = mcam_reg_read(mcam, REG_IRQSTAT);
    handled = mccic_irq(mcam, irqs);
    spin_unlock(&mcam->dev_lock);
    return IRQ_RETVAL(handled);
}


static int mmpcam_probe(struct platform_device *pdev)
{
    struct mmp_camera *cam;
    struct mcam_camera *mcam;
    struct resource *res;
    struct mmp_camera_platform_data *pdata;
    int ret;

    cam = kzalloc(sizeof(*cam), GFP_KERNEL);
    if (cam == NULL)
        return -ENOMEM;
    cam->pdev = pdev;
    INIT_LIST_HEAD(&cam->devlist);

    mcam = &cam->mcam;
    mcam->plat_power_up = mmpcam_power_up;
    mcam->plat_power_down = mmpcam_power_down;
    mcam->dev = &pdev->dev;
    mcam->use_smbus = 0;
    mcam->chip_id = V4L2_IDENT_ARMADA610;
    mcam->buffer_mode = B_DMA_sg;
    spin_lock_init(&mcam->dev_lock);
    /*
     * Get our I/O memory.
     */
    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (res == NULL) {
        dev_err(&pdev->dev, "no iomem resource!\n");
        ret = -ENODEV;
        goto out_free;
    }
    mcam->regs = ioremap(res->start, resource_size(res));
    if (mcam->regs == NULL) {
        dev_err(&pdev->dev, "MMIO ioremap fail\n");
        ret = -ENODEV;
        goto out_free;
    }
    /*
     * Power/clock memory is elsewhere; get it too.  Perhaps this
     * should really be managed outside of this driver?
     */
    res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
    if (res == NULL) {
        dev_err(&pdev->dev, "no power resource!\n");
        ret = -ENODEV;
        goto out_unmap1;
    }
    cam->power_regs = ioremap(res->start, resource_size(res));
    if (cam->power_regs == NULL) {
        dev_err(&pdev->dev, "power MMIO ioremap fail\n");
        ret = -ENODEV;
        goto out_unmap1;
    }
    /*
     * Find the i2c adapter.  This assumes, of course, that the
     * i2c bus is already up and functioning.
     */
    pdata = pdev->dev.platform_data;
    mcam->i2c_adapter = platform_get_drvdata(pdata->i2c_device);
    if (mcam->i2c_adapter == NULL) {
        ret = -ENODEV;
        dev_err(&pdev->dev, "No i2c adapter\n");
        goto out_unmap2;
    }
    /*
     * Sensor GPIO pins.
     */
    ret = gpio_request(pdata->sensor_power_gpio, "cam-power");
    if (ret) {
        dev_err(&pdev->dev, "Can't get sensor power gpio %d",
                pdata->sensor_power_gpio);
        goto out_unmap2;
    }
    gpio_direction_output(pdata->sensor_power_gpio, 0);
    ret = gpio_request(pdata->sensor_reset_gpio, "cam-reset");
    if (ret) {
        dev_err(&pdev->dev, "Can't get sensor reset gpio %d",
                pdata->sensor_reset_gpio);
        goto out_gpio;
    }
    gpio_direction_output(pdata->sensor_reset_gpio, 0);
    /*
     * Power the device up and hand it off to the core.
     */
    mmpcam_power_up(mcam);
    ret = mccic_register(mcam);
    if (ret)
        goto out_gpio2;
    /*
     * Finally, set up our IRQ now that the core is ready to
     * deal with it.
     */
    res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
    if (res == NULL) {
        ret = -ENODEV;
        goto out_unregister;
    }
    cam->irq = res->start;
    ret = request_irq(cam->irq, mmpcam_irq, IRQF_SHARED,
            "mmp-camera", mcam);
    if (ret == 0) {
        mmpcam_add_device(cam);
        return 0;
    }

out_unregister:
    mccic_shutdown(mcam);
out_gpio2:
    mmpcam_power_down(mcam);
    gpio_free(pdata->sensor_reset_gpio);
out_gpio:
    gpio_free(pdata->sensor_power_gpio);
out_unmap2:
    iounmap(cam->power_regs);
out_unmap1:
    iounmap(mcam->regs);
out_free:
    kfree(cam);
    return ret;
}


static int mmpcam_remove(struct mmp_camera *cam)
{
    struct mcam_camera *mcam = &cam->mcam;
    struct mmp_camera_platform_data *pdata;

    mmpcam_remove_device(cam);
    free_irq(cam->irq, mcam);
    mccic_shutdown(mcam);
    mmpcam_power_down(mcam);
    pdata = cam->pdev->dev.platform_data;
    gpio_free(pdata->sensor_reset_gpio);
    gpio_free(pdata->sensor_power_gpio);
    iounmap(cam->power_regs);
    iounmap(mcam->regs);
    kfree(cam);
    return 0;
}

static int mmpcam_platform_remove(struct platform_device *pdev)
{
    struct mmp_camera *cam = mmpcam_find_device(pdev);

    if (cam == NULL)
        return -ENODEV;
    return mmpcam_remove(cam);
}

/*
 * Suspend/resume support.
 */
#ifdef CONFIG_PM

static int mmpcam_suspend(struct platform_device *pdev, pm_message_t state)
{
    struct mmp_camera *cam = mmpcam_find_device(pdev);

    if (state.event != PM_EVENT_SUSPEND)
        return 0;
    mccic_suspend(&cam->mcam);
    return 0;
}

static int mmpcam_resume(struct platform_device *pdev)
{
    struct mmp_camera *cam = mmpcam_find_device(pdev);

    /*
     * Power up unconditionally just in case the core tries to
     * touch a register even if nothing was active before; trust
     * me, it's better this way.
     */
    mmpcam_power_up_ctlr(cam);
    return mccic_resume(&cam->mcam);
}

#endif


static struct platform_driver mmpcam_driver = {
    .probe      = mmpcam_probe,
    .remove     = mmpcam_platform_remove,
#ifdef CONFIG_PM
    .suspend    = mmpcam_suspend,
    .resume     = mmpcam_resume,
#endif
    .driver = {
        .name   = "mmp-camera",
        .owner  = THIS_MODULE
    }
};


static int __init mmpcam_init_module(void)
{
    mutex_init(&mmpcam_devices_lock);
    return platform_driver_register(&mmpcam_driver);
}

static void __exit mmpcam_exit_module(void)
{
    platform_driver_unregister(&mmpcam_driver);
    /*
     * platform_driver_unregister() should have emptied the list
     */
    if (!list_empty(&mmpcam_devices))
        printk(KERN_ERR "mmp_camera leaving devices behind\n");
}

module_init(mmpcam_init_module);
module_exit(mmpcam_exit_module);