/*
 *  Driver for the Conexant CX23885/7/8 PCIe bridge
 *
 *  Infrared remote control input device
 *
 *  Most of this file is
 *
 *  Copyright (C) 2009  Andy Walls <awalls@md.metrocast.net>
 *
 *  However, the cx23885_input_{init,fini} functions contained herein are
 *  derived from Linux kernel files linux/media/video/.../...-input.c marked as:
 *
 *  Copyright (C) 2008 <srinivasa.deevi at conexant dot com>
 *  Copyright (C) 2005 Ludovico Cavedon <cavedon@sssup.it>
 *                     Markus Rechberger <mrechberger@gmail.com>
 *                     Mauro Carvalho Chehab <mchehab@infradead.org>
 *                     Sascha Sommer <saschasommer@freenet.de>
 *  Copyright (C) 2004, 2005 Chris Pascoe
 *  Copyright (C) 2003, 2004 Gerd Knorr
 *  Copyright (C) 2003 Pavel Machek
 *
 *  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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 *  02110-1301, USA.
 */

#include <linux/slab.h>
#include <media/rc-core.h>
#include <media/v4l2-subdev.h>

#include "cx23885.h"

#define MODULE_NAME "cx23885"

static void cx23885_input_process_measurements(struct cx23885_dev *dev,
                                               bool overrun)
{
        struct cx23885_kernel_ir *kernel_ir = dev->kernel_ir;

        ssize_t num;
        int count, i;
        bool handle = false;
        struct ir_raw_event ir_core_event[64];

        do {
                num = 0;
                v4l2_subdev_call(dev->sd_ir, ir, rx_read, (u8 *) ir_core_event,
                                 sizeof(ir_core_event), &num);

                count = num / sizeof(struct ir_raw_event);

                for (i = 0; i < count; i++) {
                        ir_raw_event_store(kernel_ir->rc,
                                           &ir_core_event[i]);
                        handle = true;
                }
        } while (num != 0);

        if (overrun)
                ir_raw_event_reset(kernel_ir->rc);
        else if (handle)
                ir_raw_event_handle(kernel_ir->rc);
}

void cx23885_input_rx_work_handler(struct cx23885_dev *dev, u32 events)
{
        struct v4l2_subdev_ir_parameters params;
        int overrun, data_available;

        if (dev->sd_ir == NULL || events == 0)
                return;

        switch (dev->board) {
        case CX23885_BOARD_HAUPPAUGE_HVR1850:
        case CX23885_BOARD_HAUPPAUGE_HVR1290:
        case CX23885_BOARD_TEVII_S470:
        case CX23885_BOARD_HAUPPAUGE_HVR1250:
                /*
                 * The only boards we handle right now.  However other boards
                 * using the CX2388x integrated IR controller should be similar
                 */
                break;
        default:
                return;
        }

        overrun = events & (V4L2_SUBDEV_IR_RX_SW_FIFO_OVERRUN |
                            V4L2_SUBDEV_IR_RX_HW_FIFO_OVERRUN);

        data_available = events & (V4L2_SUBDEV_IR_RX_END_OF_RX_DETECTED |
                                   V4L2_SUBDEV_IR_RX_FIFO_SERVICE_REQ);

        if (overrun) {
                /* If there was a FIFO overrun, stop the device */
                v4l2_subdev_call(dev->sd_ir, ir, rx_g_parameters, &params);
                params.enable = false;
                /* Mitigate race with cx23885_input_ir_stop() */
                params.shutdown = atomic_read(&dev->ir_input_stopping);
                v4l2_subdev_call(dev->sd_ir, ir, rx_s_parameters, &params);
        }

        if (data_available)
                cx23885_input_process_measurements(dev, overrun);

        if (overrun) {
                /* If there was a FIFO overrun, clear & restart the device */
                params.enable = true;
                /* Mitigate race with cx23885_input_ir_stop() */
                params.shutdown = atomic_read(&dev->ir_input_stopping);
                v4l2_subdev_call(dev->sd_ir, ir, rx_s_parameters, &params);
        }
}

static int cx23885_input_ir_start(struct cx23885_dev *dev)
{
        struct v4l2_subdev_ir_parameters params;

        if (dev->sd_ir == NULL)
                return -ENODEV;

        atomic_set(&dev->ir_input_stopping, 0);

        v4l2_subdev_call(dev->sd_ir, ir, rx_g_parameters, &params);
        switch (dev->board) {
        case CX23885_BOARD_HAUPPAUGE_HVR1850:
        case CX23885_BOARD_HAUPPAUGE_HVR1290:
        case CX23885_BOARD_HAUPPAUGE_HVR1250:
                /*
                 * The IR controller on this board only returns pulse widths.
                 * Any other mode setting will fail to set up the device.
                */
                params.mode = V4L2_SUBDEV_IR_MODE_PULSE_WIDTH;
                params.enable = true;
                params.interrupt_enable = true;
                params.shutdown = false;

                /* Setup for baseband compatible with both RC-5 and RC-6A */
                params.modulation = false;
                /* RC-5:  2,222,222 ns = 1/36 kHz * 32 cycles * 2 marks * 1.25*/
                /* RC-6A: 3,333,333 ns = 1/36 kHz * 16 cycles * 6 marks * 1.25*/
                params.max_pulse_width = 3333333; /* ns */
                /* RC-5:    666,667 ns = 1/36 kHz * 32 cycles * 1 mark * 0.75 */
                /* RC-6A:   333,333 ns = 1/36 kHz * 16 cycles * 1 mark * 0.75 */
                params.noise_filter_min_width = 333333; /* ns */
                /*
                 * This board has inverted receive sense:
                 * mark is received as low logic level;
                 * falling edges are detected as rising edges; etc.
                 */
                params.invert_level = true;
                break;
        case CX23885_BOARD_TEVII_S470:
                /*
                 * The IR controller on this board only returns pulse widths.
                 * Any other mode setting will fail to set up the device.
                 */
                params.mode = V4L2_SUBDEV_IR_MODE_PULSE_WIDTH;
                params.enable = true;
                params.interrupt_enable = true;
                params.shutdown = false;

                /* Setup for a standard NEC protocol */
                params.carrier_freq = 37917; /* Hz, 455 kHz/12 for NEC */
                params.carrier_range_lower = 33000; /* Hz */
                params.carrier_range_upper = 43000; /* Hz */
                params.duty_cycle = 33; /* percent, 33 percent for NEC */

                /*
                 * NEC max pulse width: (64/3)/(455 kHz/12) * 16 nec_units
                 * (64/3)/(455 kHz/12) * 16 nec_units * 1.375 = 12378022 ns
                 */
                params.max_pulse_width = 12378022; /* ns */

                /*
                 * NEC noise filter min width: (64/3)/(455 kHz/12) * 1 nec_unit
                 * (64/3)/(455 kHz/12) * 1 nec_units * 0.625 = 351648 ns
                 */
                params.noise_filter_min_width = 351648; /* ns */

                params.modulation = false;
                params.invert_level = true;
                break;
        }
        v4l2_subdev_call(dev->sd_ir, ir, rx_s_parameters, &params);
        return 0;
}

static int cx23885_input_ir_open(struct rc_dev *rc)
{
        struct cx23885_kernel_ir *kernel_ir = rc->priv;

        if (kernel_ir->cx == NULL)
                return -ENODEV;

        return cx23885_input_ir_start(kernel_ir->cx);
}

static void cx23885_input_ir_stop(struct cx23885_dev *dev)
{
        struct v4l2_subdev_ir_parameters params;

        if (dev->sd_ir == NULL)
                return;

        /*
         * Stop the sd_ir subdevice from generating notifications and
         * scheduling work.
         * It is shutdown this way in order to mitigate a race with
         * cx23885_input_rx_work_handler() in the overrun case, which could
         * re-enable the subdevice.
         */
        atomic_set(&dev->ir_input_stopping, 1);
        v4l2_subdev_call(dev->sd_ir, ir, rx_g_parameters, &params);
        while (params.shutdown == false) {
                params.enable = false;
                params.interrupt_enable = false;
                params.shutdown = true;
                v4l2_subdev_call(dev->sd_ir, ir, rx_s_parameters, &params);
                v4l2_subdev_call(dev->sd_ir, ir, rx_g_parameters, &params);
        }
}

static void cx23885_input_ir_close(struct rc_dev *rc)
{
        struct cx23885_kernel_ir *kernel_ir = rc->priv;

        if (kernel_ir->cx != NULL)
                cx23885_input_ir_stop(kernel_ir->cx);
}

int cx23885_input_init(struct cx23885_dev *dev)
{
        struct cx23885_kernel_ir *kernel_ir;
        struct rc_dev *rc;
        char *rc_map;
        enum rc_driver_type driver_type;
        unsigned long allowed_protos;

        int ret;

        /*
         * If the IR device (hardware registers, chip, GPIO lines, etc.) isn't
         * encapsulated in a v4l2_subdev, then I'm not going to deal with it.
         */
        if (dev->sd_ir == NULL)
                return -ENODEV;

        switch (dev->board) {
        case CX23885_BOARD_HAUPPAUGE_HVR1850:
        case CX23885_BOARD_HAUPPAUGE_HVR1290:
        case CX23885_BOARD_HAUPPAUGE_HVR1250:
                /* Integrated CX2388[58] IR controller */
                driver_type = RC_DRIVER_IR_RAW;
                allowed_protos = RC_TYPE_ALL;
                /* The grey Hauppauge RC-5 remote */
                rc_map = RC_MAP_RC5_HAUPPAUGE_NEW;
                break;
        case CX23885_BOARD_TEVII_S470:
                /* Integrated CX23885 IR controller */
                driver_type = RC_DRIVER_IR_RAW;
                allowed_protos = RC_TYPE_ALL;
                /* A guess at the remote */
                rc_map = RC_MAP_TEVII_NEC;
                break;
        default:
                return -ENODEV;
        }

        /* cx23885 board instance kernel IR state */
        kernel_ir = kzalloc(sizeof(struct cx23885_kernel_ir), GFP_KERNEL);
        if (kernel_ir == NULL)
                return -ENOMEM;

        kernel_ir->cx = dev;
        kernel_ir->name = kasprintf(GFP_KERNEL, "cx23885 IR (%s)",
                                    cx23885_boards[dev->board].name);
        kernel_ir->phys = kasprintf(GFP_KERNEL, "pci-%s/ir0",
                                    pci_name(dev->pci));

        /* input device */
        rc = rc_allocate_device();
        if (!rc) {
                ret = -ENOMEM;
                goto err_out_free;
        }

        kernel_ir->rc = rc;
        rc->input_name = kernel_ir->name;
        rc->input_phys = kernel_ir->phys;
        rc->input_id.bustype = BUS_PCI;
        rc->input_id.version = 1;
        if (dev->pci->subsystem_vendor) {
                rc->input_id.vendor  = dev->pci->subsystem_vendor;
                rc->input_id.product = dev->pci->subsystem_device;
        } else {
                rc->input_id.vendor  = dev->pci->vendor;
                rc->input_id.product = dev->pci->device;
        }
        rc->dev.parent = &dev->pci->dev;
        rc->driver_type = driver_type;
        rc->allowed_protos = allowed_protos;
        rc->priv = kernel_ir;
        rc->open = cx23885_input_ir_open;
        rc->close = cx23885_input_ir_close;
        rc->map_name = rc_map;
        rc->driver_name = MODULE_NAME;

        /* Go */
        dev->kernel_ir = kernel_ir;
        ret = rc_register_device(rc);
        if (ret)
                goto err_out_stop;

        return 0;

err_out_stop:
        cx23885_input_ir_stop(dev);
        dev->kernel_ir = NULL;
        rc_free_device(rc);
err_out_free:
        kfree(kernel_ir->phys);
        kfree(kernel_ir->name);
        kfree(kernel_ir);
        return ret;
}

void cx23885_input_fini(struct cx23885_dev *dev)
{
        /* Always stop the IR hardware from generating interrupts */
        cx23885_input_ir_stop(dev);

        if (dev->kernel_ir == NULL)
                return;
        rc_unregister_device(dev->kernel_ir->rc);
        kfree(dev->kernel_ir->phys);
        kfree(dev->kernel_ir->name);
        kfree(dev->kernel_ir);
        dev->kernel_ir = NULL;
}