/*
 * 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 <corbet@lwn.net>
 *
 * 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/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 <corbet@lwn.net>");
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 = MCAM_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;
        }
        mcam->regs_size = resource_size(res);
        /*
         * 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);