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mcpdm.c

/*
 * 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;
}

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;
}

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;
}


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