arch/arm/mach-pxa/ssp.c - kernel/msm-4.19 - Gitiles

 /*
  *  linux/arch/arm/mach-pxa/ssp.c
  *
  *  based on linux/arch/arm/mach-sa1100/ssp.c by Russell King
  *
  *  Copyright (C) 2003 Russell King.
  *  Copyright (C) 2003 Wolfson Microelectronics PLC
  *
  * 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.
  *
  *  PXA2xx SSP driver.  This provides the generic core for simple
  *  IO-based SSP applications and allows easy port setup for DMA access.
  *
  *  Author: Liam Girdwood <liam.girdwood@wolfsonmicro.com>
  */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/errno.h>
 #include <linux/interrupt.h>
 #include <linux/ioport.h>
 #include <linux/init.h>
 #include <linux/mutex.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>

 #include <asm/irq.h>
 #include <mach/hardware.h>
 #include <mach/ssp.h>
 #include <mach/regs-ssp.h>

 #define TIMEOUT 100000

 static irqreturn_t ssp_interrupt(int irq, void *dev_id)
 {
 	struct ssp_dev *dev = dev_id;
 	struct ssp_device *ssp = dev->ssp;
 	unsigned int status;

 	status = __raw_readl(ssp->mmio_base + SSSR);
 	__raw_writel(status, ssp->mmio_base + SSSR);

 	if (status & SSSR_ROR)
 		printk(KERN_WARNING "SSP(%d): receiver overrun\n", dev->port);

 	if (status & SSSR_TUR)
 		printk(KERN_WARNING "SSP(%d): transmitter underrun\n", dev->port);

 	if (status & SSSR_BCE)
 		printk(KERN_WARNING "SSP(%d): bit count error\n", dev->port);

 	return IRQ_HANDLED;
 }

 /**
  * ssp_write_word - write a word to the SSP port
  * @data: 32-bit, MSB justified data to write.
  *
  * Wait for a free entry in the SSP transmit FIFO, and write a data
  * word to the SSP port.
  *
  * The caller is expected to perform the necessary locking.
  *
  * Returns:
  *   %-ETIMEDOUT	timeout occurred
  *   0			success
  */
 int ssp_write_word(struct ssp_dev *dev, u32 data)
 {
 	struct ssp_device *ssp = dev->ssp;
 	int timeout = TIMEOUT;

 	while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_TNF)) {
 	        if (!--timeout)
 	        	return -ETIMEDOUT;
 		cpu_relax();
 	}

 	__raw_writel(data, ssp->mmio_base + SSDR);

 	return 0;
 }

 /**
  * ssp_read_word - read a word from the SSP port
  *
  * Wait for a data word in the SSP receive FIFO, and return the
  * received data.  Data is LSB justified.
  *
  * Note: Currently, if data is not expected to be received, this
  * function will wait for ever.
  *
  * The caller is expected to perform the necessary locking.
  *
  * Returns:
  *   %-ETIMEDOUT	timeout occurred
  *   32-bit data	success
  */
 int ssp_read_word(struct ssp_dev *dev, u32 *data)
 {
 	struct ssp_device *ssp = dev->ssp;
 	int timeout = TIMEOUT;

 	while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE)) {
 	        if (!--timeout)
 	        	return -ETIMEDOUT;
 		cpu_relax();
 	}

 	*data = __raw_readl(ssp->mmio_base + SSDR);
 	return 0;
 }

 /**
  * ssp_flush - flush the transmit and receive FIFOs
  *
  * Wait for the SSP to idle, and ensure that the receive FIFO
  * is empty.
  *
  * The caller is expected to perform the necessary locking.
  */
 int ssp_flush(struct ssp_dev *dev)
 {
 	struct ssp_device *ssp = dev->ssp;
 	int timeout = TIMEOUT * 2;

 	/* ensure TX FIFO is empty instead of not full */
 	if (cpu_is_pxa3xx()) {
 		while (__raw_readl(ssp->mmio_base + SSSR) & 0xf00) {
 			if (!--timeout)
 				return -ETIMEDOUT;
 			cpu_relax();
 		}
 		timeout = TIMEOUT * 2;
 	}

 	do {
 		while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE) {
 		        if (!--timeout)
 		        	return -ETIMEDOUT;
 			(void)__raw_readl(ssp->mmio_base + SSDR);
 		}
 	        if (!--timeout)
 	        	return -ETIMEDOUT;
 	} while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_BSY);

 	return 0;
 }

 /**
  * ssp_enable - enable the SSP port
  *
  * Turn on the SSP port.
  */
 void ssp_enable(struct ssp_dev *dev)
 {
 	struct ssp_device *ssp = dev->ssp;
 	uint32_t sscr0;

 	sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
 	sscr0 |= SSCR0_SSE;
 	__raw_writel(sscr0, ssp->mmio_base + SSCR0);
 }

 /**
  * ssp_disable - shut down the SSP port
  *
  * Turn off the SSP port, optionally powering it down.
  */
 void ssp_disable(struct ssp_dev *dev)
 {
 	struct ssp_device *ssp = dev->ssp;
 	uint32_t sscr0;

 	sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
 	sscr0 &= ~SSCR0_SSE;
 	__raw_writel(sscr0, ssp->mmio_base + SSCR0);
 }

 /**
  * ssp_save_state - save the SSP configuration
  * @ssp: pointer to structure to save SSP configuration
  *
  * Save the configured SSP state for suspend.
  */
 void ssp_save_state(struct ssp_dev *dev, struct ssp_state *state)
 {
 	struct ssp_device *ssp = dev->ssp;

 	state->cr0 = __raw_readl(ssp->mmio_base + SSCR0);
 	state->cr1 = __raw_readl(ssp->mmio_base + SSCR1);
 	state->to  = __raw_readl(ssp->mmio_base + SSTO);
 	state->psp = __raw_readl(ssp->mmio_base + SSPSP);

 	ssp_disable(dev);
 }

 /**
  * ssp_restore_state - restore a previously saved SSP configuration
  * @ssp: pointer to configuration saved by ssp_save_state
  *
  * Restore the SSP configuration saved previously by ssp_save_state.
  */
 void ssp_restore_state(struct ssp_dev *dev, struct ssp_state *state)
 {
 	struct ssp_device *ssp = dev->ssp;
 	uint32_t sssr = SSSR_ROR | SSSR_TUR | SSSR_BCE;

 	__raw_writel(sssr, ssp->mmio_base + SSSR);

 	__raw_writel(state->cr0 & ~SSCR0_SSE, ssp->mmio_base + SSCR0);
 	__raw_writel(state->cr1, ssp->mmio_base + SSCR1);
 	__raw_writel(state->to,  ssp->mmio_base + SSTO);
 	__raw_writel(state->psp, ssp->mmio_base + SSPSP);
 	__raw_writel(state->cr0, ssp->mmio_base + SSCR0);
 }

 /**
  * ssp_config - configure SSP port settings
  * @mode: port operating mode
  * @flags: port config flags
  * @psp_flags: port PSP config flags
  * @speed: port speed
  *
  * Port MUST be disabled by ssp_disable before making any config changes.
  */
 int ssp_config(struct ssp_dev *dev, u32 mode, u32 flags, u32 psp_flags, u32 speed)
 {
 	struct ssp_device *ssp = dev->ssp;

 	dev->mode = mode;
 	dev->flags = flags;
 	dev->psp_flags = psp_flags;
 	dev->speed = speed;

 	/* set up port type, speed, port settings */
 	__raw_writel((dev->speed | dev->mode), ssp->mmio_base + SSCR0);
 	__raw_writel(dev->flags, ssp->mmio_base + SSCR1);
 	__raw_writel(dev->psp_flags, ssp->mmio_base + SSPSP);

 	return 0;
 }

 /**
  * ssp_init - setup the SSP port
  *
  * initialise and claim resources for the SSP port.
  *
  * Returns:
  *   %-ENODEV	if the SSP port is unavailable
  *   %-EBUSY	if the resources are already in use
  *   %0		on success
  */
 int ssp_init(struct ssp_dev *dev, u32 port, u32 init_flags)
 {
 	struct ssp_device *ssp;
 	int ret;

 	ssp = ssp_request(port, "SSP");
 	if (ssp == NULL)
 		return -ENODEV;

 	dev->ssp = ssp;
 	dev->port = port;

 	/* do we need to get irq */
 	if (!(init_flags & SSP_NO_IRQ)) {
 		ret = request_irq(ssp->irq, ssp_interrupt,
 				0, "SSP", dev);
 	    	if (ret)
 			goto out_region;
 		dev->irq = ssp->irq;
 	} else
 		dev->irq = NO_IRQ;

 	/* turn on SSP port clock */
 	clk_enable(ssp->clk);
 	return 0;

 out_region:
 	ssp_free(ssp);
 	return ret;
 }

 /**
  * ssp_exit - undo the effects of ssp_init
  *
  * release and free resources for the SSP port.
  */
 void ssp_exit(struct ssp_dev *dev)
 {
 	struct ssp_device *ssp = dev->ssp;

 	ssp_disable(dev);
 	if (dev->irq != NO_IRQ)
 		free_irq(dev->irq, dev);
 	clk_disable(ssp->clk);
 	ssp_free(ssp);
 }

 static DEFINE_MUTEX(ssp_lock);
 static LIST_HEAD(ssp_list);

 struct ssp_device *ssp_request(int port, const char *label)
 {
 	struct ssp_device *ssp = NULL;

 	mutex_lock(&ssp_lock);

 	list_for_each_entry(ssp, &ssp_list, node) {
 		if (ssp->port_id == port && ssp->use_count == 0) {
 			ssp->use_count++;
 			ssp->label = label;
 			break;
 		}
 	}

 	mutex_unlock(&ssp_lock);

 	if (&ssp->node == &ssp_list)
 		return NULL;

 	return ssp;
 }
 EXPORT_SYMBOL(ssp_request);

 void ssp_free(struct ssp_device *ssp)
 {
 	mutex_lock(&ssp_lock);
 	if (ssp->use_count) {
 		ssp->use_count--;
 		ssp->label = NULL;
 	} else
 		dev_err(&ssp->pdev->dev, "device already free\n");
 	mutex_unlock(&ssp_lock);
 }
 EXPORT_SYMBOL(ssp_free);

 static int __devinit ssp_probe(struct platform_device *pdev)
 {
 	const struct platform_device_id *id = platform_get_device_id(pdev);
 	struct resource *res;
 	struct ssp_device *ssp;
 	int ret = 0;

 	ssp = kzalloc(sizeof(struct ssp_device), GFP_KERNEL);
 	if (ssp == NULL) {
 		dev_err(&pdev->dev, "failed to allocate memory");
 		return -ENOMEM;
 	}
 	ssp->pdev = pdev;

 	ssp->clk = clk_get(&pdev->dev, NULL);
 	if (IS_ERR(ssp->clk)) {
 		ret = PTR_ERR(ssp->clk);
 		goto err_free;
 	}

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

 	res = request_mem_region(res->start, res->end - res->start + 1,
 			pdev->name);
 	if (res == NULL) {
 		dev_err(&pdev->dev, "failed to request memory resource\n");
 		ret = -EBUSY;
 		goto err_free_clk;
 	}

 	ssp->phys_base = res->start;

 	ssp->mmio_base = ioremap(res->start, res->end - res->start + 1);
 	if (ssp->mmio_base == NULL) {
 		dev_err(&pdev->dev, "failed to ioremap() registers\n");
 		ret = -ENODEV;
 		goto err_free_mem;
 	}

 	ssp->irq = platform_get_irq(pdev, 0);
 	if (ssp->irq < 0) {
 		dev_err(&pdev->dev, "no IRQ resource defined\n");
 		ret = -ENODEV;
 		goto err_free_io;
 	}

 	res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
 	if (res == NULL) {
 		dev_err(&pdev->dev, "no SSP RX DRCMR defined\n");
 		ret = -ENODEV;
 		goto err_free_io;
 	}
 	ssp->drcmr_rx = res->start;

 	res = platform_get_resource(pdev, IORESOURCE_DMA, 1);
 	if (res == NULL) {
 		dev_err(&pdev->dev, "no SSP TX DRCMR defined\n");
 		ret = -ENODEV;
 		goto err_free_io;
 	}
 	ssp->drcmr_tx = res->start;

 	/* PXA2xx/3xx SSP ports starts from 1 and the internal pdev->id
 	 * starts from 0, do a translation here
 	 */
 	ssp->port_id = pdev->id + 1;
 	ssp->use_count = 0;
 	ssp->type = (int)id->driver_data;

 	mutex_lock(&ssp_lock);
 	list_add(&ssp->node, &ssp_list);
 	mutex_unlock(&ssp_lock);

 	platform_set_drvdata(pdev, ssp);
 	return 0;

 err_free_io:
 	iounmap(ssp->mmio_base);
 err_free_mem:
 	release_mem_region(res->start, res->end - res->start + 1);
 err_free_clk:
 	clk_put(ssp->clk);
 err_free:
 	kfree(ssp);
 	return ret;
 }

 static int __devexit ssp_remove(struct platform_device *pdev)
 {
 	struct resource *res;
 	struct ssp_device *ssp;

 	ssp = platform_get_drvdata(pdev);
 	if (ssp == NULL)
 		return -ENODEV;

 	iounmap(ssp->mmio_base);

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	release_mem_region(res->start, res->end - res->start + 1);

 	clk_put(ssp->clk);

 	mutex_lock(&ssp_lock);
 	list_del(&ssp->node);
 	mutex_unlock(&ssp_lock);

 	kfree(ssp);
 	return 0;
 }

 static const struct platform_device_id ssp_id_table[] = {
 	{ "pxa25x-ssp",		PXA25x_SSP },
 	{ "pxa25x-nssp",	PXA25x_NSSP },
 	{ "pxa27x-ssp",		PXA27x_SSP },
 	{ },
 };

 static struct platform_driver ssp_driver = {
 	.probe		= ssp_probe,
 	.remove		= __devexit_p(ssp_remove),
 	.driver		= {
 		.owner	= THIS_MODULE,
 		.name	= "pxa2xx-ssp",
 	},
 	.id_table	= ssp_id_table,
 };

 static int __init pxa_ssp_init(void)
 {
 	return platform_driver_register(&ssp_driver);
 }

 static void __exit pxa_ssp_exit(void)
 {
 	platform_driver_unregister(&ssp_driver);
 }

 arch_initcall(pxa_ssp_init);
 module_exit(pxa_ssp_exit);

 EXPORT_SYMBOL(ssp_write_word);
 EXPORT_SYMBOL(ssp_read_word);
 EXPORT_SYMBOL(ssp_flush);
 EXPORT_SYMBOL(ssp_enable);
 EXPORT_SYMBOL(ssp_disable);
 EXPORT_SYMBOL(ssp_save_state);
 EXPORT_SYMBOL(ssp_restore_state);
 EXPORT_SYMBOL(ssp_init);
 EXPORT_SYMBOL(ssp_exit);
 EXPORT_SYMBOL(ssp_config);

 MODULE_DESCRIPTION("PXA SSP driver");
 MODULE_AUTHOR("Liam Girdwood");
 MODULE_LICENSE("GPL");
	/*
	* linux/arch/arm/mach-pxa/ssp.c
	*
	* based on linux/arch/arm/mach-sa1100/ssp.c by Russell King
	*
	* Copyright (C) 2003 Russell King.
	* Copyright (C) 2003 Wolfson Microelectronics PLC
	*
	* 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.
	*
	* PXA2xx SSP driver. This provides the generic core for simple
	* IO-based SSP applications and allows easy port setup for DMA access.
	*
	* Author: Liam Girdwood <liam.girdwood@wolfsonmicro.com>
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/errno.h>
	#include <linux/interrupt.h>
	#include <linux/ioport.h>
	#include <linux/init.h>
	#include <linux/mutex.h>
	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/platform_device.h>
	#include <linux/io.h>

	#include <asm/irq.h>
	#include <mach/hardware.h>
	#include <mach/ssp.h>
	#include <mach/regs-ssp.h>

	#define TIMEOUT 100000

	static irqreturn_t ssp_interrupt(int irq, void *dev_id)
	{
	struct ssp_dev *dev = dev_id;
	struct ssp_device *ssp = dev->ssp;
	unsigned int status;

	status = __raw_readl(ssp->mmio_base + SSSR);
	__raw_writel(status, ssp->mmio_base + SSSR);

	if (status & SSSR_ROR)
	printk(KERN_WARNING "SSP(%d): receiver overrun\n", dev->port);

	if (status & SSSR_TUR)
	printk(KERN_WARNING "SSP(%d): transmitter underrun\n", dev->port);

	if (status & SSSR_BCE)
	printk(KERN_WARNING "SSP(%d): bit count error\n", dev->port);

	return IRQ_HANDLED;
	}

	/**
	* ssp_write_word - write a word to the SSP port
	* @data: 32-bit, MSB justified data to write.
	*
	* Wait for a free entry in the SSP transmit FIFO, and write a data
	* word to the SSP port.
	*
	* The caller is expected to perform the necessary locking.
	*
	* Returns:
	* %-ETIMEDOUT timeout occurred
	* 0 success
	*/
	int ssp_write_word(struct ssp_dev *dev, u32 data)
	{
	struct ssp_device *ssp = dev->ssp;
	int timeout = TIMEOUT;

	while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_TNF)) {
	if (!--timeout)
	return -ETIMEDOUT;
	cpu_relax();
	}

	__raw_writel(data, ssp->mmio_base + SSDR);

	return 0;
	}

	/**
	* ssp_read_word - read a word from the SSP port
	*
	* Wait for a data word in the SSP receive FIFO, and return the
	* received data. Data is LSB justified.
	*
	* Note: Currently, if data is not expected to be received, this
	* function will wait for ever.
	*
	* The caller is expected to perform the necessary locking.
	*
	* Returns:
	* %-ETIMEDOUT timeout occurred
	* 32-bit data success
	*/
	int ssp_read_word(struct ssp_dev dev, u32 data)
	{
	struct ssp_device *ssp = dev->ssp;
	int timeout = TIMEOUT;

	while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE)) {
	if (!--timeout)
	return -ETIMEDOUT;
	cpu_relax();
	}

	*data = __raw_readl(ssp->mmio_base + SSDR);
	return 0;
	}

	/**
	* ssp_flush - flush the transmit and receive FIFOs
	*
	* Wait for the SSP to idle, and ensure that the receive FIFO
	* is empty.
	*
	* The caller is expected to perform the necessary locking.
	*/
	int ssp_flush(struct ssp_dev *dev)
	{
	struct ssp_device *ssp = dev->ssp;
	int timeout = TIMEOUT * 2;

	/* ensure TX FIFO is empty instead of not full */
	if (cpu_is_pxa3xx()) {
	while (__raw_readl(ssp->mmio_base + SSSR) & 0xf00) {
	if (!--timeout)
	return -ETIMEDOUT;
	cpu_relax();
	}
	timeout = TIMEOUT * 2;
	}

	do {
	while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE) {
	if (!--timeout)
	return -ETIMEDOUT;
	(void)__raw_readl(ssp->mmio_base + SSDR);
	}
	if (!--timeout)
	return -ETIMEDOUT;
	} while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_BSY);

	return 0;
	}

	/**
	* ssp_enable - enable the SSP port
	*
	* Turn on the SSP port.
	*/
	void ssp_enable(struct ssp_dev *dev)
	{
	struct ssp_device *ssp = dev->ssp;
	uint32_t sscr0;

	sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
	sscr0 \|= SSCR0_SSE;
	__raw_writel(sscr0, ssp->mmio_base + SSCR0);
	}

	/**
	* ssp_disable - shut down the SSP port
	*
	* Turn off the SSP port, optionally powering it down.
	*/
	void ssp_disable(struct ssp_dev *dev)
	{
	struct ssp_device *ssp = dev->ssp;
	uint32_t sscr0;

	sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
	sscr0 &= ~SSCR0_SSE;
	__raw_writel(sscr0, ssp->mmio_base + SSCR0);
	}

	/**
	* ssp_save_state - save the SSP configuration
	* @ssp: pointer to structure to save SSP configuration
	*
	* Save the configured SSP state for suspend.
	*/
	void ssp_save_state(struct ssp_dev dev, struct ssp_state state)
	{
	struct ssp_device *ssp = dev->ssp;

	state->cr0 = __raw_readl(ssp->mmio_base + SSCR0);
	state->cr1 = __raw_readl(ssp->mmio_base + SSCR1);
	state->to = __raw_readl(ssp->mmio_base + SSTO);
	state->psp = __raw_readl(ssp->mmio_base + SSPSP);

	ssp_disable(dev);
	}

	/**
	* ssp_restore_state - restore a previously saved SSP configuration
	* @ssp: pointer to configuration saved by ssp_save_state
	*
	* Restore the SSP configuration saved previously by ssp_save_state.
	*/
	void ssp_restore_state(struct ssp_dev dev, struct ssp_state state)
	{
	struct ssp_device *ssp = dev->ssp;
	uint32_t sssr = SSSR_ROR \| SSSR_TUR \| SSSR_BCE;

	__raw_writel(sssr, ssp->mmio_base + SSSR);

	__raw_writel(state->cr0 & ~SSCR0_SSE, ssp->mmio_base + SSCR0);
	__raw_writel(state->cr1, ssp->mmio_base + SSCR1);
	__raw_writel(state->to, ssp->mmio_base + SSTO);
	__raw_writel(state->psp, ssp->mmio_base + SSPSP);
	__raw_writel(state->cr0, ssp->mmio_base + SSCR0);
	}

	/**
	* ssp_config - configure SSP port settings
	* @mode: port operating mode
	* @flags: port config flags
	* @psp_flags: port PSP config flags
	* @speed: port speed
	*
	* Port MUST be disabled by ssp_disable before making any config changes.
	*/
	int ssp_config(struct ssp_dev *dev, u32 mode, u32 flags, u32 psp_flags, u32 speed)
	{
	struct ssp_device *ssp = dev->ssp;

	dev->mode = mode;
	dev->flags = flags;
	dev->psp_flags = psp_flags;
	dev->speed = speed;

	/* set up port type, speed, port settings */
	__raw_writel((dev->speed \| dev->mode), ssp->mmio_base + SSCR0);
	__raw_writel(dev->flags, ssp->mmio_base + SSCR1);
	__raw_writel(dev->psp_flags, ssp->mmio_base + SSPSP);

	return 0;
	}

	/**
	* ssp_init - setup the SSP port
	*
	* initialise and claim resources for the SSP port.
	*
	* Returns:
	* %-ENODEV if the SSP port is unavailable
	* %-EBUSY if the resources are already in use
	* %0 on success
	*/
	int ssp_init(struct ssp_dev *dev, u32 port, u32 init_flags)
	{
	struct ssp_device *ssp;
	int ret;

	ssp = ssp_request(port, "SSP");
	if (ssp == NULL)
	return -ENODEV;

	dev->ssp = ssp;
	dev->port = port;

	/* do we need to get irq */
	if (!(init_flags & SSP_NO_IRQ)) {
	ret = request_irq(ssp->irq, ssp_interrupt,
	0, "SSP", dev);
	if (ret)
	goto out_region;
	dev->irq = ssp->irq;
	} else
	dev->irq = NO_IRQ;

	/* turn on SSP port clock */
	clk_enable(ssp->clk);
	return 0;

	out_region:
	ssp_free(ssp);
	return ret;
	}

	/**
	* ssp_exit - undo the effects of ssp_init
	*
	* release and free resources for the SSP port.
	*/
	void ssp_exit(struct ssp_dev *dev)
	{
	struct ssp_device *ssp = dev->ssp;

	ssp_disable(dev);
	if (dev->irq != NO_IRQ)
	free_irq(dev->irq, dev);
	clk_disable(ssp->clk);
	ssp_free(ssp);
	}

	static DEFINE_MUTEX(ssp_lock);
	static LIST_HEAD(ssp_list);

	struct ssp_device ssp_request(int port, const char label)
	{
	struct ssp_device *ssp = NULL;

	mutex_lock(&ssp_lock);

	list_for_each_entry(ssp, &ssp_list, node) {
	if (ssp->port_id == port && ssp->use_count == 0) {
	ssp->use_count++;
	ssp->label = label;
	break;
	}
	}

	mutex_unlock(&ssp_lock);

	if (&ssp->node == &ssp_list)
	return NULL;

	return ssp;
	}
	EXPORT_SYMBOL(ssp_request);

	void ssp_free(struct ssp_device *ssp)
	{
	mutex_lock(&ssp_lock);
	if (ssp->use_count) {
	ssp->use_count--;
	ssp->label = NULL;
	} else
	dev_err(&ssp->pdev->dev, "device already free\n");
	mutex_unlock(&ssp_lock);
	}
	EXPORT_SYMBOL(ssp_free);

	static int __devinit ssp_probe(struct platform_device *pdev)
	{
	const struct platform_device_id *id = platform_get_device_id(pdev);
	struct resource *res;
	struct ssp_device *ssp;
	int ret = 0;

	ssp = kzalloc(sizeof(struct ssp_device), GFP_KERNEL);
	if (ssp == NULL) {
	dev_err(&pdev->dev, "failed to allocate memory");
	return -ENOMEM;
	}
	ssp->pdev = pdev;

	ssp->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(ssp->clk)) {
	ret = PTR_ERR(ssp->clk);
	goto err_free;
	}

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

	res = request_mem_region(res->start, res->end - res->start + 1,
	pdev->name);
	if (res == NULL) {
	dev_err(&pdev->dev, "failed to request memory resource\n");
	ret = -EBUSY;
	goto err_free_clk;
	}

	ssp->phys_base = res->start;

	ssp->mmio_base = ioremap(res->start, res->end - res->start + 1);
	if (ssp->mmio_base == NULL) {
	dev_err(&pdev->dev, "failed to ioremap() registers\n");
	ret = -ENODEV;
	goto err_free_mem;
	}

	ssp->irq = platform_get_irq(pdev, 0);
	if (ssp->irq < 0) {
	dev_err(&pdev->dev, "no IRQ resource defined\n");
	ret = -ENODEV;
	goto err_free_io;
	}

	res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
	if (res == NULL) {
	dev_err(&pdev->dev, "no SSP RX DRCMR defined\n");
	ret = -ENODEV;
	goto err_free_io;
	}
	ssp->drcmr_rx = res->start;

	res = platform_get_resource(pdev, IORESOURCE_DMA, 1);
	if (res == NULL) {
	dev_err(&pdev->dev, "no SSP TX DRCMR defined\n");
	ret = -ENODEV;
	goto err_free_io;
	}
	ssp->drcmr_tx = res->start;

	/* PXA2xx/3xx SSP ports starts from 1 and the internal pdev->id
	* starts from 0, do a translation here
	*/
	ssp->port_id = pdev->id + 1;
	ssp->use_count = 0;
	ssp->type = (int)id->driver_data;

	mutex_lock(&ssp_lock);
	list_add(&ssp->node, &ssp_list);
	mutex_unlock(&ssp_lock);

	platform_set_drvdata(pdev, ssp);
	return 0;

	err_free_io:
	iounmap(ssp->mmio_base);
	err_free_mem:
	release_mem_region(res->start, res->end - res->start + 1);
	err_free_clk:
	clk_put(ssp->clk);
	err_free:
	kfree(ssp);
	return ret;
	}

	static int __devexit ssp_remove(struct platform_device *pdev)
	{
	struct resource *res;
	struct ssp_device *ssp;

	ssp = platform_get_drvdata(pdev);
	if (ssp == NULL)
	return -ENODEV;

	iounmap(ssp->mmio_base);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(res->start, res->end - res->start + 1);

	clk_put(ssp->clk);

	mutex_lock(&ssp_lock);
	list_del(&ssp->node);
	mutex_unlock(&ssp_lock);

	kfree(ssp);
	return 0;
	}

	static const struct platform_device_id ssp_id_table[] = {
	{ "pxa25x-ssp", PXA25x_SSP },
	{ "pxa25x-nssp", PXA25x_NSSP },
	{ "pxa27x-ssp", PXA27x_SSP },
	{ },
	};

	static struct platform_driver ssp_driver = {
	.probe = ssp_probe,
	.remove = __devexit_p(ssp_remove),
	.driver = {
	.owner = THIS_MODULE,
	.name = "pxa2xx-ssp",
	},
	.id_table = ssp_id_table,
	};

	static int __init pxa_ssp_init(void)
	{
	return platform_driver_register(&ssp_driver);
	}

	static void __exit pxa_ssp_exit(void)
	{
	platform_driver_unregister(&ssp_driver);
	}

	arch_initcall(pxa_ssp_init);
	module_exit(pxa_ssp_exit);

	EXPORT_SYMBOL(ssp_write_word);
	EXPORT_SYMBOL(ssp_read_word);
	EXPORT_SYMBOL(ssp_flush);
	EXPORT_SYMBOL(ssp_enable);
	EXPORT_SYMBOL(ssp_disable);
	EXPORT_SYMBOL(ssp_save_state);
	EXPORT_SYMBOL(ssp_restore_state);
	EXPORT_SYMBOL(ssp_init);
	EXPORT_SYMBOL(ssp_exit);
	EXPORT_SYMBOL(ssp_config);

	MODULE_DESCRIPTION("PXA SSP driver");
	MODULE_AUTHOR("Liam Girdwood");
	MODULE_LICENSE("GPL");