drivers/i2c/busses/i2c-au1550.c - kernel/msm-4.9 - Gitiles

 /*
  * i2c-au1550.c: SMBus (i2c) adapter for Alchemy PSC interface
  * Copyright (C) 2004 Embedded Edge, LLC <dan@embeddededge.com>
  *
  * 2.6 port by Matt Porter <mporter@kernel.crashing.org>
  *
  * The documentation describes this as an SMBus controller, but it doesn't
  * understand any of the SMBus protocol in hardware.  It's really an I2C
  * controller that could emulate most of the SMBus in software.
  *
  * This is just a skeleton adapter to use with the Au1550 PSC
  * algorithm.  It was developed for the Pb1550, but will work with
  * any Au1550 board that has a similar PSC configuration.
  *
  * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */

 #include <linux/delay.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>

 #include <asm/mach-au1x00/au1000.h>
 #include <asm/mach-au1x00/au1xxx_psc.h>

 #define PSC_SEL		0x00
 #define PSC_CTRL	0x04
 #define PSC_SMBCFG	0x08
 #define PSC_SMBMSK	0x0C
 #define PSC_SMBPCR	0x10
 #define PSC_SMBSTAT	0x14
 #define PSC_SMBEVNT	0x18
 #define PSC_SMBTXRX	0x1C
 #define PSC_SMBTMR	0x20

 struct i2c_au1550_data {
 	void __iomem *psc_base;
 	int	xfer_timeout;
 	struct i2c_adapter adap;
 	struct resource *ioarea;
 };

 static inline void WR(struct i2c_au1550_data *a, int r, unsigned long v)
 {
 	__raw_writel(v, a->psc_base + r);
 	wmb();
 }

 static inline unsigned long RD(struct i2c_au1550_data *a, int r)
 {
 	return __raw_readl(a->psc_base + r);
 }

 static int wait_xfer_done(struct i2c_au1550_data *adap)
 {
 	int i;

 	/* Wait for Tx Buffer Empty */
 	for (i = 0; i < adap->xfer_timeout; i++) {
 		if (RD(adap, PSC_SMBSTAT) & PSC_SMBSTAT_TE)
 			return 0;

 		udelay(1);
 	}

 	return -ETIMEDOUT;
 }

 static int wait_ack(struct i2c_au1550_data *adap)
 {
 	unsigned long stat;

 	if (wait_xfer_done(adap))
 		return -ETIMEDOUT;

 	stat = RD(adap, PSC_SMBEVNT);
 	if ((stat & (PSC_SMBEVNT_DN | PSC_SMBEVNT_AN | PSC_SMBEVNT_AL)) != 0)
 		return -ETIMEDOUT;

 	return 0;
 }

 static int wait_master_done(struct i2c_au1550_data *adap)
 {
 	int i;

 	/* Wait for Master Done. */
 	for (i = 0; i < 2 * adap->xfer_timeout; i++) {
 		if ((RD(adap, PSC_SMBEVNT) & PSC_SMBEVNT_MD) != 0)
 			return 0;
 		udelay(1);
 	}

 	return -ETIMEDOUT;
 }

 static int
 do_address(struct i2c_au1550_data *adap, unsigned int addr, int rd, int q)
 {
 	unsigned long stat;

 	/* Reset the FIFOs, clear events. */
 	stat = RD(adap, PSC_SMBSTAT);
 	WR(adap, PSC_SMBEVNT, PSC_SMBEVNT_ALLCLR);

 	if (!(stat & PSC_SMBSTAT_TE) || !(stat & PSC_SMBSTAT_RE)) {
 		WR(adap, PSC_SMBPCR, PSC_SMBPCR_DC);
 		while ((RD(adap, PSC_SMBPCR) & PSC_SMBPCR_DC) != 0)
 			cpu_relax();
 		udelay(50);
 	}

 	/* Write out the i2c chip address and specify operation */
 	addr <<= 1;
 	if (rd)
 		addr |= 1;

 	/* zero-byte xfers stop immediately */
 	if (q)
 		addr |= PSC_SMBTXRX_STP;

 	/* Put byte into fifo, start up master. */
 	WR(adap, PSC_SMBTXRX, addr);
 	WR(adap, PSC_SMBPCR, PSC_SMBPCR_MS);
 	if (wait_ack(adap))
 		return -EIO;
 	return (q) ? wait_master_done(adap) : 0;
 }

 static int wait_for_rx_byte(struct i2c_au1550_data *adap, unsigned char *out)
 {
 	int j;

 	if (wait_xfer_done(adap))
 		return -EIO;

 	j =  adap->xfer_timeout * 100;
 	do {
 		j--;
 		if (j <= 0)
 			return -EIO;

 		if ((RD(adap, PSC_SMBSTAT) & PSC_SMBSTAT_RE) == 0)
 			j = 0;
 		else
 			udelay(1);
 	} while (j > 0);

 	*out = RD(adap, PSC_SMBTXRX);

 	return 0;
 }

 static int i2c_read(struct i2c_au1550_data *adap, unsigned char *buf,
 		    unsigned int len)
 {
 	int i;

 	if (len == 0)
 		return 0;

 	/* A read is performed by stuffing the transmit fifo with
 	 * zero bytes for timing, waiting for bytes to appear in the
 	 * receive fifo, then reading the bytes.
 	 */
 	i = 0;
 	while (i < (len - 1)) {
 		WR(adap, PSC_SMBTXRX, 0);
 		if (wait_for_rx_byte(adap, &buf[i]))
 			return -EIO;

 		i++;
 	}

 	/* The last byte has to indicate transfer done. */
 	WR(adap, PSC_SMBTXRX, PSC_SMBTXRX_STP);
 	if (wait_master_done(adap))
 		return -EIO;

 	buf[i] = (unsigned char)(RD(adap, PSC_SMBTXRX) & 0xff);
 	return 0;
 }

 static int i2c_write(struct i2c_au1550_data *adap, unsigned char *buf,
 		     unsigned int len)
 {
 	int i;
 	unsigned long data;

 	if (len == 0)
 		return 0;

 	i = 0;
 	while (i < (len-1)) {
 		data = buf[i];
 		WR(adap, PSC_SMBTXRX, data);
 		if (wait_ack(adap))
 			return -EIO;
 		i++;
 	}

 	/* The last byte has to indicate transfer done. */
 	data = buf[i];
 	data |= PSC_SMBTXRX_STP;
 	WR(adap, PSC_SMBTXRX, data);
 	if (wait_master_done(adap))
 		return -EIO;
 	return 0;
 }

 static int
 au1550_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
 {
 	struct i2c_au1550_data *adap = i2c_adap->algo_data;
 	struct i2c_msg *p;
 	int i, err = 0;

 	WR(adap, PSC_CTRL, PSC_CTRL_ENABLE);

 	for (i = 0; !err && i < num; i++) {
 		p = &msgs[i];
 		err = do_address(adap, p->addr, p->flags & I2C_M_RD,
 				 (p->len == 0));
 		if (err || !p->len)
 			continue;
 		if (p->flags & I2C_M_RD)
 			err = i2c_read(adap, p->buf, p->len);
 		else
 			err = i2c_write(adap, p->buf, p->len);
 	}

 	/* Return the number of messages processed, or the error code.
 	*/
 	if (err == 0)
 		err = num;

 	WR(adap, PSC_CTRL, PSC_CTRL_SUSPEND);

 	return err;
 }

 static u32 au1550_func(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }

 static const struct i2c_algorithm au1550_algo = {
 	.master_xfer	= au1550_xfer,
 	.functionality	= au1550_func,
 };

 static void i2c_au1550_setup(struct i2c_au1550_data *priv)
 {
 	unsigned long cfg;

 	WR(priv, PSC_CTRL, PSC_CTRL_DISABLE);
 	WR(priv, PSC_SEL, PSC_SEL_PS_SMBUSMODE);
 	WR(priv, PSC_SMBCFG, 0);
 	WR(priv, PSC_CTRL, PSC_CTRL_ENABLE);
 	while ((RD(priv, PSC_SMBSTAT) & PSC_SMBSTAT_SR) == 0)
 		cpu_relax();

 	cfg = PSC_SMBCFG_RT_FIFO8 | PSC_SMBCFG_TT_FIFO8 | PSC_SMBCFG_DD_DISABLE;
 	WR(priv, PSC_SMBCFG, cfg);

 	/* Divide by 8 to get a 6.25 MHz clock.  The later protocol
 	 * timings are based on this clock.
 	 */
 	cfg |= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8);
 	WR(priv, PSC_SMBCFG, cfg);
 	WR(priv, PSC_SMBMSK, PSC_SMBMSK_ALLMASK);

 	/* Set the protocol timer values.  See Table 71 in the
 	 * Au1550 Data Book for standard timing values.
 	 */
 	WR(priv, PSC_SMBTMR, PSC_SMBTMR_SET_TH(0) | PSC_SMBTMR_SET_PS(15) | \
 		PSC_SMBTMR_SET_PU(15) | PSC_SMBTMR_SET_SH(15) | \
 		PSC_SMBTMR_SET_SU(15) | PSC_SMBTMR_SET_CL(15) | \
 		PSC_SMBTMR_SET_CH(15));

 	cfg |= PSC_SMBCFG_DE_ENABLE;
 	WR(priv, PSC_SMBCFG, cfg);
 	while ((RD(priv, PSC_SMBSTAT) & PSC_SMBSTAT_SR) == 0)
 		cpu_relax();

 	WR(priv, PSC_CTRL, PSC_CTRL_SUSPEND);
 }

 static void i2c_au1550_disable(struct i2c_au1550_data *priv)
 {
 	WR(priv, PSC_SMBCFG, 0);
 	WR(priv, PSC_CTRL, PSC_CTRL_DISABLE);
 }

 /*
  * registering functions to load algorithms at runtime
  * Prior to calling us, the 50MHz clock frequency and routing
  * must have been set up for the PSC indicated by the adapter.
  */
 static int __devinit
 i2c_au1550_probe(struct platform_device *pdev)
 {
 	struct i2c_au1550_data *priv;
 	struct resource *r;
 	int ret;

 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!r) {
 		ret = -ENODEV;
 		goto out;
 	}

 	priv = kzalloc(sizeof(struct i2c_au1550_data), GFP_KERNEL);
 	if (!priv) {
 		ret = -ENOMEM;
 		goto out;
 	}

 	priv->ioarea = request_mem_region(r->start, resource_size(r),
 					  pdev->name);
 	if (!priv->ioarea) {
 		ret = -EBUSY;
 		goto out_mem;
 	}

 	priv->psc_base = ioremap(r->start, resource_size(r));
 	if (!priv->psc_base) {
 		ret = -EIO;
 		goto out_map;
 	}
 	priv->xfer_timeout = 200;

 	priv->adap.nr = pdev->id;
 	priv->adap.algo = &au1550_algo;
 	priv->adap.algo_data = priv;
 	priv->adap.dev.parent = &pdev->dev;
 	strlcpy(priv->adap.name, "Au1xxx PSC I2C", sizeof(priv->adap.name));

 	/* Now, set up the PSC for SMBus PIO mode. */
 	i2c_au1550_setup(priv);

 	ret = i2c_add_numbered_adapter(&priv->adap);
 	if (ret == 0) {
 		platform_set_drvdata(pdev, priv);
 		return 0;
 	}

 	i2c_au1550_disable(priv);
 	iounmap(priv->psc_base);
 out_map:
 	release_resource(priv->ioarea);
 	kfree(priv->ioarea);
 out_mem:
 	kfree(priv);
 out:
 	return ret;
 }

 static int __devexit i2c_au1550_remove(struct platform_device *pdev)
 {
 	struct i2c_au1550_data *priv = platform_get_drvdata(pdev);

 	platform_set_drvdata(pdev, NULL);
 	i2c_del_adapter(&priv->adap);
 	i2c_au1550_disable(priv);
 	iounmap(priv->psc_base);
 	release_resource(priv->ioarea);
 	kfree(priv->ioarea);
 	kfree(priv);
 	return 0;
 }

 #ifdef CONFIG_PM
 static int i2c_au1550_suspend(struct device *dev)
 {
 	struct i2c_au1550_data *priv = dev_get_drvdata(dev);

 	i2c_au1550_disable(priv);

 	return 0;
 }

 static int i2c_au1550_resume(struct device *dev)
 {
 	struct i2c_au1550_data *priv = dev_get_drvdata(dev);

 	i2c_au1550_setup(priv);

 	return 0;
 }

 static const struct dev_pm_ops i2c_au1550_pmops = {
 	.suspend	= i2c_au1550_suspend,
 	.resume		= i2c_au1550_resume,
 };

 #define AU1XPSC_SMBUS_PMOPS (&i2c_au1550_pmops)

 #else
 #define AU1XPSC_SMBUS_PMOPS NULL
 #endif

 static struct platform_driver au1xpsc_smbus_driver = {
 	.driver = {
 		.name	= "au1xpsc_smbus",
 		.owner	= THIS_MODULE,
 		.pm	= AU1XPSC_SMBUS_PMOPS,
 	},
 	.probe		= i2c_au1550_probe,
 	.remove		= __devexit_p(i2c_au1550_remove),
 };

 module_platform_driver(au1xpsc_smbus_driver);

 MODULE_AUTHOR("Dan Malek, Embedded Edge, LLC.");
 MODULE_DESCRIPTION("SMBus adapter Alchemy pb1550");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:au1xpsc_smbus");
	/*
	* i2c-au1550.c: SMBus (i2c) adapter for Alchemy PSC interface
	* Copyright (C) 2004 Embedded Edge, LLC <dan@embeddededge.com>
	*
	* 2.6 port by Matt Porter <mporter@kernel.crashing.org>
	*
	* The documentation describes this as an SMBus controller, but it doesn't
	* understand any of the SMBus protocol in hardware. It's really an I2C
	* controller that could emulate most of the SMBus in software.
	*
	* This is just a skeleton adapter to use with the Au1550 PSC
	* algorithm. It was developed for the Pb1550, but will work with
	* any Au1550 board that has a similar PSC configuration.
	*
	* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	*/

	#include <linux/delay.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/init.h>
	#include <linux/errno.h>
	#include <linux/i2c.h>
	#include <linux/slab.h>

	#include <asm/mach-au1x00/au1000.h>
	#include <asm/mach-au1x00/au1xxx_psc.h>

	#define PSC_SEL 0x00
	#define PSC_CTRL 0x04
	#define PSC_SMBCFG 0x08
	#define PSC_SMBMSK 0x0C
	#define PSC_SMBPCR 0x10
	#define PSC_SMBSTAT 0x14
	#define PSC_SMBEVNT 0x18
	#define PSC_SMBTXRX 0x1C
	#define PSC_SMBTMR 0x20

	struct i2c_au1550_data {
	void __iomem *psc_base;
	int xfer_timeout;
	struct i2c_adapter adap;
	struct resource *ioarea;
	};

	static inline void WR(struct i2c_au1550_data *a, int r, unsigned long v)
	{
	__raw_writel(v, a->psc_base + r);
	wmb();
	}

	static inline unsigned long RD(struct i2c_au1550_data *a, int r)
	{
	return __raw_readl(a->psc_base + r);
	}

	static int wait_xfer_done(struct i2c_au1550_data *adap)
	{
	int i;

	/* Wait for Tx Buffer Empty */
	for (i = 0; i < adap->xfer_timeout; i++) {
	if (RD(adap, PSC_SMBSTAT) & PSC_SMBSTAT_TE)
	return 0;

	udelay(1);
	}

	return -ETIMEDOUT;
	}

	static int wait_ack(struct i2c_au1550_data *adap)
	{
	unsigned long stat;

	if (wait_xfer_done(adap))
	return -ETIMEDOUT;

	stat = RD(adap, PSC_SMBEVNT);
	if ((stat & (PSC_SMBEVNT_DN \| PSC_SMBEVNT_AN \| PSC_SMBEVNT_AL)) != 0)
	return -ETIMEDOUT;

	return 0;
	}

	static int wait_master_done(struct i2c_au1550_data *adap)
	{
	int i;

	/* Wait for Master Done. */
	for (i = 0; i < 2 * adap->xfer_timeout; i++) {
	if ((RD(adap, PSC_SMBEVNT) & PSC_SMBEVNT_MD) != 0)
	return 0;
	udelay(1);
	}

	return -ETIMEDOUT;
	}

	static int
	do_address(struct i2c_au1550_data *adap, unsigned int addr, int rd, int q)
	{
	unsigned long stat;

	/* Reset the FIFOs, clear events. */
	stat = RD(adap, PSC_SMBSTAT);
	WR(adap, PSC_SMBEVNT, PSC_SMBEVNT_ALLCLR);

	if (!(stat & PSC_SMBSTAT_TE) \|\| !(stat & PSC_SMBSTAT_RE)) {
	WR(adap, PSC_SMBPCR, PSC_SMBPCR_DC);
	while ((RD(adap, PSC_SMBPCR) & PSC_SMBPCR_DC) != 0)
	cpu_relax();
	udelay(50);
	}

	/* Write out the i2c chip address and specify operation */
	addr <<= 1;
	if (rd)
	addr \|= 1;

	/* zero-byte xfers stop immediately */
	if (q)
	addr \|= PSC_SMBTXRX_STP;

	/* Put byte into fifo, start up master. */
	WR(adap, PSC_SMBTXRX, addr);
	WR(adap, PSC_SMBPCR, PSC_SMBPCR_MS);
	if (wait_ack(adap))
	return -EIO;
	return (q) ? wait_master_done(adap) : 0;
	}

	static int wait_for_rx_byte(struct i2c_au1550_data adap, unsigned char out)
	{
	int j;

	if (wait_xfer_done(adap))
	return -EIO;

	j = adap->xfer_timeout * 100;
	do {
	j--;
	if (j <= 0)
	return -EIO;

	if ((RD(adap, PSC_SMBSTAT) & PSC_SMBSTAT_RE) == 0)
	j = 0;
	else
	udelay(1);
	} while (j > 0);

	*out = RD(adap, PSC_SMBTXRX);

	return 0;
	}

	static int i2c_read(struct i2c_au1550_data adap, unsigned char buf,
	unsigned int len)
	{
	int i;

	if (len == 0)
	return 0;

	/* A read is performed by stuffing the transmit fifo with
	* zero bytes for timing, waiting for bytes to appear in the
	* receive fifo, then reading the bytes.
	*/
	i = 0;
	while (i < (len - 1)) {
	WR(adap, PSC_SMBTXRX, 0);
	if (wait_for_rx_byte(adap, &buf[i]))
	return -EIO;

	i++;
	}

	/* The last byte has to indicate transfer done. */
	WR(adap, PSC_SMBTXRX, PSC_SMBTXRX_STP);
	if (wait_master_done(adap))
	return -EIO;

	buf[i] = (unsigned char)(RD(adap, PSC_SMBTXRX) & 0xff);
	return 0;
	}

	static int i2c_write(struct i2c_au1550_data adap, unsigned char buf,
	unsigned int len)
	{
	int i;
	unsigned long data;

	if (len == 0)
	return 0;

	i = 0;
	while (i < (len-1)) {
	data = buf[i];
	WR(adap, PSC_SMBTXRX, data);
	if (wait_ack(adap))
	return -EIO;
	i++;
	}

	/* The last byte has to indicate transfer done. */
	data = buf[i];
	data \|= PSC_SMBTXRX_STP;
	WR(adap, PSC_SMBTXRX, data);
	if (wait_master_done(adap))
	return -EIO;
	return 0;
	}

	static int
	au1550_xfer(struct i2c_adapter i2c_adap, struct i2c_msg msgs, int num)
	{
	struct i2c_au1550_data *adap = i2c_adap->algo_data;
	struct i2c_msg *p;
	int i, err = 0;

	WR(adap, PSC_CTRL, PSC_CTRL_ENABLE);

	for (i = 0; !err && i < num; i++) {
	p = &msgs[i];
	err = do_address(adap, p->addr, p->flags & I2C_M_RD,
	(p->len == 0));
	if (err \|\| !p->len)
	continue;
	if (p->flags & I2C_M_RD)
	err = i2c_read(adap, p->buf, p->len);
	else
	err = i2c_write(adap, p->buf, p->len);
	}

	/* Return the number of messages processed, or the error code.
	*/
	if (err == 0)
	err = num;

	WR(adap, PSC_CTRL, PSC_CTRL_SUSPEND);

	return err;
	}

	static u32 au1550_func(struct i2c_adapter *adap)
	{
	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL;
	}

	static const struct i2c_algorithm au1550_algo = {
	.master_xfer = au1550_xfer,
	.functionality = au1550_func,
	};

	static void i2c_au1550_setup(struct i2c_au1550_data *priv)
	{
	unsigned long cfg;

	WR(priv, PSC_CTRL, PSC_CTRL_DISABLE);
	WR(priv, PSC_SEL, PSC_SEL_PS_SMBUSMODE);
	WR(priv, PSC_SMBCFG, 0);
	WR(priv, PSC_CTRL, PSC_CTRL_ENABLE);
	while ((RD(priv, PSC_SMBSTAT) & PSC_SMBSTAT_SR) == 0)
	cpu_relax();

	cfg = PSC_SMBCFG_RT_FIFO8 \| PSC_SMBCFG_TT_FIFO8 \| PSC_SMBCFG_DD_DISABLE;
	WR(priv, PSC_SMBCFG, cfg);

	/* Divide by 8 to get a 6.25 MHz clock. The later protocol
	* timings are based on this clock.
	*/
	cfg \|= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8);
	WR(priv, PSC_SMBCFG, cfg);
	WR(priv, PSC_SMBMSK, PSC_SMBMSK_ALLMASK);

	/* Set the protocol timer values. See Table 71 in the
	* Au1550 Data Book for standard timing values.
	*/
	WR(priv, PSC_SMBTMR, PSC_SMBTMR_SET_TH(0) \| PSC_SMBTMR_SET_PS(15) \| \
	PSC_SMBTMR_SET_PU(15) \| PSC_SMBTMR_SET_SH(15) \| \
	PSC_SMBTMR_SET_SU(15) \| PSC_SMBTMR_SET_CL(15) \| \
	PSC_SMBTMR_SET_CH(15));

	cfg \|= PSC_SMBCFG_DE_ENABLE;
	WR(priv, PSC_SMBCFG, cfg);
	while ((RD(priv, PSC_SMBSTAT) & PSC_SMBSTAT_SR) == 0)
	cpu_relax();

	WR(priv, PSC_CTRL, PSC_CTRL_SUSPEND);
	}

	static void i2c_au1550_disable(struct i2c_au1550_data *priv)
	{
	WR(priv, PSC_SMBCFG, 0);
	WR(priv, PSC_CTRL, PSC_CTRL_DISABLE);
	}

	/*
	* registering functions to load algorithms at runtime
	* Prior to calling us, the 50MHz clock frequency and routing
	* must have been set up for the PSC indicated by the adapter.
	*/
	static int __devinit
	i2c_au1550_probe(struct platform_device *pdev)
	{
	struct i2c_au1550_data *priv;
	struct resource *r;
	int ret;

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!r) {
	ret = -ENODEV;
	goto out;
	}

	priv = kzalloc(sizeof(struct i2c_au1550_data), GFP_KERNEL);
	if (!priv) {
	ret = -ENOMEM;
	goto out;
	}

	priv->ioarea = request_mem_region(r->start, resource_size(r),
	pdev->name);
	if (!priv->ioarea) {
	ret = -EBUSY;
	goto out_mem;
	}

	priv->psc_base = ioremap(r->start, resource_size(r));
	if (!priv->psc_base) {
	ret = -EIO;
	goto out_map;
	}
	priv->xfer_timeout = 200;

	priv->adap.nr = pdev->id;
	priv->adap.algo = &au1550_algo;
	priv->adap.algo_data = priv;
	priv->adap.dev.parent = &pdev->dev;
	strlcpy(priv->adap.name, "Au1xxx PSC I2C", sizeof(priv->adap.name));

	/* Now, set up the PSC for SMBus PIO mode. */
	i2c_au1550_setup(priv);

	ret = i2c_add_numbered_adapter(&priv->adap);
	if (ret == 0) {
	platform_set_drvdata(pdev, priv);
	return 0;
	}

	i2c_au1550_disable(priv);
	iounmap(priv->psc_base);
	out_map:
	release_resource(priv->ioarea);
	kfree(priv->ioarea);
	out_mem:
	kfree(priv);
	out:
	return ret;
	}

	static int __devexit i2c_au1550_remove(struct platform_device *pdev)
	{
	struct i2c_au1550_data *priv = platform_get_drvdata(pdev);

	platform_set_drvdata(pdev, NULL);
	i2c_del_adapter(&priv->adap);
	i2c_au1550_disable(priv);
	iounmap(priv->psc_base);
	release_resource(priv->ioarea);
	kfree(priv->ioarea);
	kfree(priv);
	return 0;
	}

	#ifdef CONFIG_PM
	static int i2c_au1550_suspend(struct device *dev)
	{
	struct i2c_au1550_data *priv = dev_get_drvdata(dev);

	i2c_au1550_disable(priv);

	return 0;
	}

	static int i2c_au1550_resume(struct device *dev)
	{
	struct i2c_au1550_data *priv = dev_get_drvdata(dev);

	i2c_au1550_setup(priv);

	return 0;
	}

	static const struct dev_pm_ops i2c_au1550_pmops = {
	.suspend = i2c_au1550_suspend,
	.resume = i2c_au1550_resume,
	};

	#define AU1XPSC_SMBUS_PMOPS (&i2c_au1550_pmops)

	#else
	#define AU1XPSC_SMBUS_PMOPS NULL
	#endif

	static struct platform_driver au1xpsc_smbus_driver = {
	.driver = {
	.name = "au1xpsc_smbus",
	.owner = THIS_MODULE,
	.pm = AU1XPSC_SMBUS_PMOPS,
	},
	.probe = i2c_au1550_probe,
	.remove = __devexit_p(i2c_au1550_remove),
	};

	module_platform_driver(au1xpsc_smbus_driver);

	MODULE_AUTHOR("Dan Malek, Embedded Edge, LLC.");
	MODULE_DESCRIPTION("SMBus adapter Alchemy pb1550");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:au1xpsc_smbus");