/*
 * mcpdm.c  --  McPDM interface driver
 *
 * Author: Jorge Eduardo Candelaria <x0107209@ti.com>
 * Copyright (C) 2009 - Texas Instruments, Inc.
 *
 * 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.
 *
 * 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 St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/irq.h>

#include "mcpdm.h"

static struct omap_mcpdm *mcpdm;

static inline void omap_mcpdm_write(u16 reg, u32 val)
{
       __raw_writel(val, mcpdm->io_base + reg);
}

static inline int omap_mcpdm_read(u16 reg)
{
       return __raw_readl(mcpdm->io_base + reg);
}

static void omap_mcpdm_reg_dump(void)
{
       dev_dbg(mcpdm->dev, "***********************\n");
       dev_dbg(mcpdm->dev, "IRQSTATUS_RAW:  0x%04x\n",
                       omap_mcpdm_read(MCPDM_IRQSTATUS_RAW));
       dev_dbg(mcpdm->dev, "IRQSTATUS:  0x%04x\n",
                       omap_mcpdm_read(MCPDM_IRQSTATUS));
       dev_dbg(mcpdm->dev, "IRQENABLE_SET:  0x%04x\n",
                       omap_mcpdm_read(MCPDM_IRQENABLE_SET));
       dev_dbg(mcpdm->dev, "IRQENABLE_CLR:  0x%04x\n",
                       omap_mcpdm_read(MCPDM_IRQENABLE_CLR));
       dev_dbg(mcpdm->dev, "IRQWAKE_EN: 0x%04x\n",
                       omap_mcpdm_read(MCPDM_IRQWAKE_EN));
       dev_dbg(mcpdm->dev, "DMAENABLE_SET: 0x%04x\n",
                       omap_mcpdm_read(MCPDM_DMAENABLE_SET));
       dev_dbg(mcpdm->dev, "DMAENABLE_CLR:  0x%04x\n",
                       omap_mcpdm_read(MCPDM_DMAENABLE_CLR));
       dev_dbg(mcpdm->dev, "DMAWAKEEN:  0x%04x\n",
                       omap_mcpdm_read(MCPDM_DMAWAKEEN));
       dev_dbg(mcpdm->dev, "CTRL:  0x%04x\n",
                       omap_mcpdm_read(MCPDM_CTRL));
       dev_dbg(mcpdm->dev, "DN_DATA:  0x%04x\n",
                       omap_mcpdm_read(MCPDM_DN_DATA));
       dev_dbg(mcpdm->dev, "UP_DATA: 0x%04x\n",
                       omap_mcpdm_read(MCPDM_UP_DATA));
       dev_dbg(mcpdm->dev, "FIFO_CTRL_DN: 0x%04x\n",
                       omap_mcpdm_read(MCPDM_FIFO_CTRL_DN));
       dev_dbg(mcpdm->dev, "FIFO_CTRL_UP:  0x%04x\n",
                       omap_mcpdm_read(MCPDM_FIFO_CTRL_UP));
       dev_dbg(mcpdm->dev, "DN_OFFSET:  0x%04x\n",
                       omap_mcpdm_read(MCPDM_DN_OFFSET));
       dev_dbg(mcpdm->dev, "***********************\n");
}

/*
 * Takes the McPDM module in and out of reset state.
 * Uplink and downlink can be reset individually.
 */
static void omap_mcpdm_reset_capture(int reset)
{
       int ctrl = omap_mcpdm_read(MCPDM_CTRL);

       if (reset)
               ctrl |= SW_UP_RST;
       else
               ctrl &= ~SW_UP_RST;

       omap_mcpdm_write(MCPDM_CTRL, ctrl);
}

static void omap_mcpdm_reset_playback(int reset)
{
       int ctrl = omap_mcpdm_read(MCPDM_CTRL);

       if (reset)
               ctrl |= SW_DN_RST;
       else
               ctrl &= ~SW_DN_RST;

       omap_mcpdm_write(MCPDM_CTRL, ctrl);
}

/*
 * Enables the transfer through the PDM interface to/from the Phoenix
 * codec by enabling the corresponding UP or DN channels.
 */
void omap_mcpdm_start(int stream)
{
       int ctrl = omap_mcpdm_read(MCPDM_CTRL);

       if (stream)
               ctrl |= mcpdm->up_channels;
       else
               ctrl |= mcpdm->dn_channels;

       omap_mcpdm_write(MCPDM_CTRL, ctrl);
}

/*
 * Disables the transfer through the PDM interface to/from the Phoenix
 * codec by disabling the corresponding UP or DN channels.
 */
void omap_mcpdm_stop(int stream)
{
       int ctrl = omap_mcpdm_read(MCPDM_CTRL);

       if (stream)
               ctrl &= ~mcpdm->up_channels;
       else
               ctrl &= ~mcpdm->dn_channels;

       omap_mcpdm_write(MCPDM_CTRL, ctrl);
}

/*
 * Configures McPDM uplink for audio recording.
 * This function should be called before omap_mcpdm_start.
 */
int omap_mcpdm_capture_open(struct omap_mcpdm_link *uplink)
{
       int irq_mask = 0;
       int ctrl;

       if (!uplink)
               return -EINVAL;

       mcpdm->uplink = uplink;

       /* Enable irq request generation */
       irq_mask |= uplink->irq_mask & MCPDM_UPLINK_IRQ_MASK;
       omap_mcpdm_write(MCPDM_IRQENABLE_SET, irq_mask);

       /* Configure uplink threshold */
       if (uplink->threshold > UP_THRES_MAX)
               uplink->threshold = UP_THRES_MAX;

       omap_mcpdm_write(MCPDM_FIFO_CTRL_UP, uplink->threshold);

       /* Configure DMA controller */
       omap_mcpdm_write(MCPDM_DMAENABLE_SET, DMA_UP_ENABLE);

       /* Set pdm out format */
       ctrl = omap_mcpdm_read(MCPDM_CTRL);
       ctrl &= ~PDMOUTFORMAT;
       ctrl |= uplink->format & PDMOUTFORMAT;

       /* Uplink channels */
       mcpdm->up_channels = uplink->channels & (PDM_UP_MASK | PDM_STATUS_MASK);

       omap_mcpdm_write(MCPDM_CTRL, ctrl);

       return 0;
}

/*
 * Configures McPDM downlink for audio playback.
 * This function should be called before omap_mcpdm_start.
 */
int omap_mcpdm_playback_open(struct omap_mcpdm_link *downlink)
{
       int irq_mask = 0;
       int ctrl;

       if (!downlink)
               return -EINVAL;

       mcpdm->downlink = downlink;

       /* Enable irq request generation */
       irq_mask |= downlink->irq_mask & MCPDM_DOWNLINK_IRQ_MASK;
       omap_mcpdm_write(MCPDM_IRQENABLE_SET, irq_mask);

       /* Configure uplink threshold */
       if (downlink->threshold > DN_THRES_MAX)
               downlink->threshold = DN_THRES_MAX;

       omap_mcpdm_write(MCPDM_FIFO_CTRL_DN, downlink->threshold);

       /* Enable DMA request generation */
       omap_mcpdm_write(MCPDM_DMAENABLE_SET, DMA_DN_ENABLE);

       /* Set pdm out format */
       ctrl = omap_mcpdm_read(MCPDM_CTRL);
       ctrl &= ~PDMOUTFORMAT;
       ctrl |= downlink->format & PDMOUTFORMAT;

       /* Downlink channels */
       mcpdm->dn_channels = downlink->channels & (PDM_DN_MASK | PDM_CMD_MASK);

       omap_mcpdm_write(MCPDM_CTRL, ctrl);

       return 0;
}

/*
 * Cleans McPDM uplink configuration.
 * This function should be called when the stream is closed.
 */
int omap_mcpdm_capture_close(struct omap_mcpdm_link *uplink)
{
       int irq_mask = 0;

       if (!uplink)
               return -EINVAL;

       /* Disable irq request generation */
       irq_mask |= uplink->irq_mask & MCPDM_UPLINK_IRQ_MASK;
       omap_mcpdm_write(MCPDM_IRQENABLE_CLR, irq_mask);

       /* Disable DMA request generation */
       omap_mcpdm_write(MCPDM_DMAENABLE_CLR, DMA_UP_ENABLE);

       /* Clear Downlink channels */
       mcpdm->up_channels = 0;

       mcpdm->uplink = NULL;

       return 0;
}

/*
 * Cleans McPDM downlink configuration.
 * This function should be called when the stream is closed.
 */
int omap_mcpdm_playback_close(struct omap_mcpdm_link *downlink)
{
       int irq_mask = 0;

       if (!downlink)
               return -EINVAL;

       /* Disable irq request generation */
       irq_mask |= downlink->irq_mask & MCPDM_DOWNLINK_IRQ_MASK;
       omap_mcpdm_write(MCPDM_IRQENABLE_CLR, irq_mask);

       /* Disable DMA request generation */
       omap_mcpdm_write(MCPDM_DMAENABLE_CLR, DMA_DN_ENABLE);

       /* clear Downlink channels */
       mcpdm->dn_channels = 0;

       mcpdm->downlink = NULL;

       return 0;
}

static irqreturn_t omap_mcpdm_irq_handler(int irq, void *dev_id)
{
       struct omap_mcpdm *mcpdm_irq = dev_id;
       int irq_status;

       irq_status = omap_mcpdm_read(MCPDM_IRQSTATUS);

       /* Acknowledge irq event */
       omap_mcpdm_write(MCPDM_IRQSTATUS, irq_status);

       if (irq & MCPDM_DN_IRQ_FULL) {
               dev_err(mcpdm_irq->dev, "DN FIFO error %x\n", irq_status);
               omap_mcpdm_reset_playback(1);
               omap_mcpdm_playback_open(mcpdm_irq->downlink);
               omap_mcpdm_reset_playback(0);
       }

       if (irq & MCPDM_DN_IRQ_EMPTY) {
               dev_err(mcpdm_irq->dev, "DN FIFO error %x\n", irq_status);
               omap_mcpdm_reset_playback(1);
               omap_mcpdm_playback_open(mcpdm_irq->downlink);
               omap_mcpdm_reset_playback(0);
       }

       if (irq & MCPDM_DN_IRQ) {
               dev_dbg(mcpdm_irq->dev, "DN write request\n");
       }

       if (irq & MCPDM_UP_IRQ_FULL) {
               dev_err(mcpdm_irq->dev, "UP FIFO error %x\n", irq_status);
               omap_mcpdm_reset_capture(1);
               omap_mcpdm_capture_open(mcpdm_irq->uplink);
               omap_mcpdm_reset_capture(0);
       }

       if (irq & MCPDM_UP_IRQ_EMPTY) {
               dev_err(mcpdm_irq->dev, "UP FIFO error %x\n", irq_status);
               omap_mcpdm_reset_capture(1);
               omap_mcpdm_capture_open(mcpdm_irq->uplink);
               omap_mcpdm_reset_capture(0);
       }

       if (irq & MCPDM_UP_IRQ) {
               dev_dbg(mcpdm_irq->dev, "UP write request\n");
       }

       return IRQ_HANDLED;
}

int omap_mcpdm_request(void)
{
       int ret;

       clk_enable(mcpdm->clk);

       spin_lock(&mcpdm->lock);

       if (!mcpdm->free) {
               dev_err(mcpdm->dev, "McPDM interface is in use\n");
               spin_unlock(&mcpdm->lock);
               ret = -EBUSY;
               goto err;
       }
       mcpdm->free = 0;

       spin_unlock(&mcpdm->lock);

       /* Disable lines while request is ongoing */
       omap_mcpdm_write(MCPDM_CTRL, 0x00);

       ret = request_irq(mcpdm->irq, omap_mcpdm_irq_handler,
                               0, "McPDM", (void *)mcpdm);
       if (ret) {
               dev_err(mcpdm->dev, "Request for McPDM IRQ failed\n");
               goto err;
       }

       return 0;

err:
       clk_disable(mcpdm->clk);
       return ret;
}

void omap_mcpdm_free(void)
{
       spin_lock(&mcpdm->lock);
       if (mcpdm->free) {
               dev_err(mcpdm->dev, "McPDM interface is already free\n");
               spin_unlock(&mcpdm->lock);
               return;
       }
       mcpdm->free = 1;
       spin_unlock(&mcpdm->lock);

       clk_disable(mcpdm->clk);

       free_irq(mcpdm->irq, (void *)mcpdm);
}

/* Enable/disable DC offset cancelation for the analog
 * headset path (PDM channels 1 and 2).
 */
int omap_mcpdm_set_offset(int offset1, int offset2)
{
       int offset;

       if ((offset1 > DN_OFST_MAX) || (offset2 > DN_OFST_MAX))
               return -EINVAL;

       offset = (offset1 << DN_OFST_RX1) | (offset2 << DN_OFST_RX2);

       /* offset cancellation for channel 1 */
       if (offset1)
               offset |= DN_OFST_RX1_EN;
       else
               offset &= ~DN_OFST_RX1_EN;

       /* offset cancellation for channel 2 */
       if (offset2)
               offset |= DN_OFST_RX2_EN;
       else
               offset &= ~DN_OFST_RX2_EN;

       omap_mcpdm_write(MCPDM_DN_OFFSET, offset);

       return 0;
}

static int __devinit omap_mcpdm_probe(struct platform_device *pdev)
{
       struct resource *res;
       int ret = 0;

       mcpdm = kzalloc(sizeof(struct omap_mcpdm), GFP_KERNEL);
       if (!mcpdm) {
               ret = -ENOMEM;
               goto exit;
       }

       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
       if (res == NULL) {
               dev_err(&pdev->dev, "no resource\n");
               goto err_resource;
       }

       spin_lock_init(&mcpdm->lock);
       mcpdm->free = 1;
       mcpdm->io_base = ioremap(res->start, resource_size(res));
       if (!mcpdm->io_base) {
               ret = -ENOMEM;
               goto err_resource;
       }

       mcpdm->irq = platform_get_irq(pdev, 0);

       mcpdm->clk = clk_get(&pdev->dev, "pdm_ck");
       if (IS_ERR(mcpdm->clk)) {
               ret = PTR_ERR(mcpdm->clk);
               dev_err(&pdev->dev, "unable to get pdm_ck: %d\n", ret);
               goto err_clk;
       }

       mcpdm->dev = &pdev->dev;
       platform_set_drvdata(pdev, mcpdm);

       return 0;

err_clk:
       iounmap(mcpdm->io_base);
err_resource:
       kfree(mcpdm);
exit:
       return ret;
}

static int __devexit omap_mcpdm_remove(struct platform_device *pdev)
{
       struct omap_mcpdm *mcpdm_ptr = platform_get_drvdata(pdev);

       platform_set_drvdata(pdev, NULL);

       clk_put(mcpdm_ptr->clk);

       iounmap(mcpdm_ptr->io_base);

       mcpdm_ptr->clk = NULL;
       mcpdm_ptr->free = 0;
       mcpdm_ptr->dev = NULL;

       kfree(mcpdm_ptr);

       return 0;
}

static struct platform_driver omap_mcpdm_driver = {
       .probe = omap_mcpdm_probe,
       .remove = __devexit_p(omap_mcpdm_remove),
       .driver = {
               .name = "omap-mcpdm",
       },
};

static struct platform_device *omap_mcpdm_device;

static int __init omap_mcpdm_init(void)
{
       return platform_driver_register(&omap_mcpdm_driver);
}
arch_initcall(omap_mcpdm_init);