ASoC: fsl_ssi: Switch to SPDX identifier

/*

 * Freescale SSI ALSA SoC Digital Audio Interface (DAI) driver

 *

 * Author: Timur Tabi <timur@freescale.com>

 *

 * Copyright 2007-2010 Freescale Semiconductor, Inc.

 *

 * This file is licensed under the terms of the GNU General Public License

 * version 2.  This program is licensed "as is" without any warranty of any

 * kind, whether express or implied.

 *

 *

 * Some notes why imx-pcm-fiq is used instead of DMA on some boards:

 *

 * The i.MX SSI core has some nasty limitations in AC97 mode. While most

 * sane processor vendors have a FIFO per AC97 slot, the i.MX has only

 * one FIFO which combines all valid receive slots. We cannot even select

 * which slots we want to receive. The WM9712 with which this driver

 * was developed with always sends GPIO status data in slot 12 which

 * we receive in our (PCM-) data stream. The only chance we have is to

 * manually skip this data in the FIQ handler. With sampling rates different

 * from 48000Hz not every frame has valid receive data, so the ratio

 * between pcm data and GPIO status data changes. Our FIQ handler is not

 * able to handle this, hence this driver only works with 48000Hz sampling

 * rate.

 * Reading and writing AC97 registers is another challenge. The core

 * provides us status bits when the read register is updated with *another*

 * value. When we read the same register two times (and the register still

 * contains the same value) these status bits are not set. We work

 * around this by not polling these bits but only wait a fixed delay.

 */

// SPDX-License-Identifier: GPL-2.0

//

// Freescale SSI ALSA SoC Digital Audio Interface (DAI) driver

//

// Author: Timur Tabi <timur@freescale.com>

//

// Copyright 2007-2010 Freescale Semiconductor, Inc.

//

// Some notes why imx-pcm-fiq is used instead of DMA on some boards:

//

// The i.MX SSI core has some nasty limitations in AC97 mode. While most

// sane processor vendors have a FIFO per AC97 slot, the i.MX has only

// one FIFO which combines all valid receive slots. We cannot even select

// which slots we want to receive. The WM9712 with which this driver

// was developed with always sends GPIO status data in slot 12 which

// we receive in our (PCM-) data stream. The only chance we have is to

// manually skip this data in the FIQ handler. With sampling rates different

// from 48000Hz not every frame has valid receive data, so the ratio

// between pcm data and GPIO status data changes. Our FIQ handler is not

// able to handle this, hence this driver only works with 48000Hz sampling

// rate.

// Reading and writing AC97 registers is another challenge. The core

// provides us status bits when the read register is updated with *another*

// value. When we read the same register two times (and the register still

// contains the same value) these status bits are not set. We work

// around this by not polling these bits but only wait a fixed delay.

#include <linux/init.h>

#include <linux/io.h>

/* SPDX-License-Identifier: GPL-2.0 */

/*

 * fsl_ssi.h - ALSA SSI interface for the Freescale MPC8610 and i.MX SoC

 *

 * Author: Timur Tabi <timur@freescale.com>

 *

 * Copyright 2007-2008 Freescale Semiconductor, Inc.  This file is licensed

 * under the terms of the GNU General Public License version 2.  This

 * program is licensed "as is" without any warranty of any kind, whether

 * express or implied.

 * Copyright 2007-2008 Freescale Semiconductor, Inc.

 */

#ifndef _MPC8610_I2S_H

/*

 * Freescale SSI ALSA SoC Digital Audio Interface (DAI) debugging functions

 *

 * Copyright 2014 Markus Pargmann <mpa@pengutronix.de>, Pengutronix

 *

 * Splitted from fsl_ssi.c

 *

 * This file is licensed under the terms of the GNU General Public License

 * version 2.  This program is licensed "as is" without any warranty of any

 * kind, whether express or implied.

 */

// SPDX-License-Identifier: GPL-2.0

//

// Freescale SSI ALSA SoC Digital Audio Interface (DAI) debugging functions

//

// Copyright 2014 Markus Pargmann <mpa@pengutronix.de>, Pengutronix

//

// Split from fsl_ssi.c

#include <linux/debugfs.h>

#include <linux/device.h>