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

 /*
  * (C) Copyright 2003-2004
  * Humboldt Solutions Ltd, adrian@humboldt.co.uk.

  * This is a combined i2c adapter and algorithm driver for the
  * MPC107/Tsi107 PowerPC northbridge and processors that include
  * the same I2C unit (8240, 8245, 85xx).
  *
  * Release 0.8
  *
  * 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.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/init.h>
 #include <linux/of_platform.h>
 #include <linux/of_i2c.h>
 #include <linux/slab.h>

 #include <linux/io.h>
 #include <linux/fsl_devices.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>

 #include <asm/mpc52xx.h>
 #include <sysdev/fsl_soc.h>

 #define DRV_NAME "mpc-i2c"

 #define MPC_I2C_CLOCK_LEGACY   0
 #define MPC_I2C_CLOCK_PRESERVE (~0U)

 #define MPC_I2C_FDR   0x04
 #define MPC_I2C_CR    0x08
 #define MPC_I2C_SR    0x0c
 #define MPC_I2C_DR    0x10
 #define MPC_I2C_DFSRR 0x14

 #define CCR_MEN  0x80
 #define CCR_MIEN 0x40
 #define CCR_MSTA 0x20
 #define CCR_MTX  0x10
 #define CCR_TXAK 0x08
 #define CCR_RSTA 0x04

 #define CSR_MCF  0x80
 #define CSR_MAAS 0x40
 #define CSR_MBB  0x20
 #define CSR_MAL  0x10
 #define CSR_SRW  0x04
 #define CSR_MIF  0x02
 #define CSR_RXAK 0x01

 struct mpc_i2c {
 	struct device *dev;
 	void __iomem *base;
 	u32 interrupt;
 	wait_queue_head_t queue;
 	struct i2c_adapter adap;
 	int irq;
 	u32 real_clk;
 #ifdef CONFIG_PM
 	u8 fdr, dfsrr;
 #endif
 };

 struct mpc_i2c_divider {
 	u16 divider;
 	u16 fdr;	/* including dfsrr */
 };

 struct mpc_i2c_data {
 	void (*setup)(struct device_node *node, struct mpc_i2c *i2c,
 		      u32 clock, u32 prescaler);
 	u32 prescaler;
 };

 static inline void writeccr(struct mpc_i2c *i2c, u32 x)
 {
 	writeb(x, i2c->base + MPC_I2C_CR);
 }

 static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
 {
 	struct mpc_i2c *i2c = dev_id;
 	if (readb(i2c->base + MPC_I2C_SR) & CSR_MIF) {
 		/* Read again to allow register to stabilise */
 		i2c->interrupt = readb(i2c->base + MPC_I2C_SR);
 		writeb(0, i2c->base + MPC_I2C_SR);
 		wake_up(&i2c->queue);
 	}
 	return IRQ_HANDLED;
 }

 /* Sometimes 9th clock pulse isn't generated, and slave doesn't release
  * the bus, because it wants to send ACK.
  * Following sequence of enabling/disabling and sending start/stop generates
  * the 9 pulses, so it's all OK.
  */
 static void mpc_i2c_fixup(struct mpc_i2c *i2c)
 {
 	int k;
 	u32 delay_val = 1000000 / i2c->real_clk + 1;

 	if (delay_val < 2)
 		delay_val = 2;

 	for (k = 9; k; k--) {
 		writeccr(i2c, 0);
 		writeccr(i2c, CCR_MSTA | CCR_MTX | CCR_MEN);
 		udelay(delay_val);
 		writeccr(i2c, CCR_MEN);
 		udelay(delay_val << 1);
 	}
 }

 static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
 {
 	unsigned long orig_jiffies = jiffies;
 	u32 x;
 	int result = 0;

 	if (!i2c->irq) {
 		while (!(readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
 			schedule();
 			if (time_after(jiffies, orig_jiffies + timeout)) {
 				dev_dbg(i2c->dev, "timeout\n");
 				writeccr(i2c, 0);
 				result = -EIO;
 				break;
 			}
 		}
 		x = readb(i2c->base + MPC_I2C_SR);
 		writeb(0, i2c->base + MPC_I2C_SR);
 	} else {
 		/* Interrupt mode */
 		result = wait_event_timeout(i2c->queue,
 			(i2c->interrupt & CSR_MIF), timeout);

 		if (unlikely(!(i2c->interrupt & CSR_MIF))) {
 			dev_dbg(i2c->dev, "wait timeout\n");
 			writeccr(i2c, 0);
 			result = -ETIMEDOUT;
 		}

 		x = i2c->interrupt;
 		i2c->interrupt = 0;
 	}

 	if (result < 0)
 		return result;

 	if (!(x & CSR_MCF)) {
 		dev_dbg(i2c->dev, "unfinished\n");
 		return -EIO;
 	}

 	if (x & CSR_MAL) {
 		dev_dbg(i2c->dev, "MAL\n");
 		return -EIO;
 	}

 	if (writing && (x & CSR_RXAK)) {
 		dev_dbg(i2c->dev, "No RXAK\n");
 		/* generate stop */
 		writeccr(i2c, CCR_MEN);
 		return -EIO;
 	}
 	return 0;
 }

 #if defined(CONFIG_PPC_MPC52xx) || defined(CONFIG_PPC_MPC512x)
 static const struct mpc_i2c_divider mpc_i2c_dividers_52xx[] = {
 	{20, 0x20}, {22, 0x21}, {24, 0x22}, {26, 0x23},
 	{28, 0x24}, {30, 0x01}, {32, 0x25}, {34, 0x02},
 	{36, 0x26}, {40, 0x27}, {44, 0x04}, {48, 0x28},
 	{52, 0x63}, {56, 0x29}, {60, 0x41}, {64, 0x2a},
 	{68, 0x07}, {72, 0x2b}, {80, 0x2c}, {88, 0x09},
 	{96, 0x2d}, {104, 0x0a}, {112, 0x2e}, {120, 0x81},
 	{128, 0x2f}, {136, 0x47}, {144, 0x0c}, {160, 0x30},
 	{176, 0x49}, {192, 0x31}, {208, 0x4a}, {224, 0x32},
 	{240, 0x0f}, {256, 0x33}, {272, 0x87}, {288, 0x10},
 	{320, 0x34}, {352, 0x89}, {384, 0x35}, {416, 0x8a},
 	{448, 0x36}, {480, 0x13}, {512, 0x37}, {576, 0x14},
 	{640, 0x38}, {768, 0x39}, {896, 0x3a}, {960, 0x17},
 	{1024, 0x3b}, {1152, 0x18}, {1280, 0x3c}, {1536, 0x3d},
 	{1792, 0x3e}, {1920, 0x1b}, {2048, 0x3f}, {2304, 0x1c},
 	{2560, 0x1d}, {3072, 0x1e}, {3584, 0x7e}, {3840, 0x1f},
 	{4096, 0x7f}, {4608, 0x5c}, {5120, 0x5d}, {6144, 0x5e},
 	{7168, 0xbe}, {7680, 0x5f}, {8192, 0xbf}, {9216, 0x9c},
 	{10240, 0x9d}, {12288, 0x9e}, {15360, 0x9f}
 };

 static int mpc_i2c_get_fdr_52xx(struct device_node *node, u32 clock,
 					  int prescaler, u32 *real_clk)
 {
 	const struct mpc_i2c_divider *div = NULL;
 	unsigned int pvr = mfspr(SPRN_PVR);
 	u32 divider;
 	int i;

 	if (clock == MPC_I2C_CLOCK_LEGACY) {
 		/* see below - default fdr = 0x3f -> div = 2048 */
 		*real_clk = mpc5xxx_get_bus_frequency(node) / 2048;
 		return -EINVAL;
 	}

 	/* Determine divider value */
 	divider = mpc5xxx_get_bus_frequency(node) / clock;

 	/*
 	 * We want to choose an FDR/DFSR that generates an I2C bus speed that
 	 * is equal to or lower than the requested speed.
 	 */
 	for (i = 0; i < ARRAY_SIZE(mpc_i2c_dividers_52xx); i++) {
 		div = &mpc_i2c_dividers_52xx[i];
 		/* Old MPC5200 rev A CPUs do not support the high bits */
 		if (div->fdr & 0xc0 && pvr == 0x80822011)
 			continue;
 		if (div->divider >= divider)
 			break;
 	}

 	*real_clk = mpc5xxx_get_bus_frequency(node) / div->divider;
 	return (int)div->fdr;
 }

 static void mpc_i2c_setup_52xx(struct device_node *node,
 					 struct mpc_i2c *i2c,
 					 u32 clock, u32 prescaler)
 {
 	int ret, fdr;

 	if (clock == MPC_I2C_CLOCK_PRESERVE) {
 		dev_dbg(i2c->dev, "using fdr %d\n",
 			readb(i2c->base + MPC_I2C_FDR));
 		return;
 	}

 	ret = mpc_i2c_get_fdr_52xx(node, clock, prescaler, &i2c->real_clk);
 	fdr = (ret >= 0) ? ret : 0x3f; /* backward compatibility */

 	writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);

 	if (ret >= 0)
 		dev_info(i2c->dev, "clock %u Hz (fdr=%d)\n", i2c->real_clk,
 			 fdr);
 }
 #else /* !(CONFIG_PPC_MPC52xx || CONFIG_PPC_MPC512x) */
 static void mpc_i2c_setup_52xx(struct device_node *node,
 					 struct mpc_i2c *i2c,
 					 u32 clock, u32 prescaler)
 {
 }
 #endif /* CONFIG_PPC_MPC52xx || CONFIG_PPC_MPC512x */

 #ifdef CONFIG_PPC_MPC512x
 static void mpc_i2c_setup_512x(struct device_node *node,
 					 struct mpc_i2c *i2c,
 					 u32 clock, u32 prescaler)
 {
 	struct device_node *node_ctrl;
 	void __iomem *ctrl;
 	const u32 *pval;
 	u32 idx;

 	/* Enable I2C interrupts for mpc5121 */
 	node_ctrl = of_find_compatible_node(NULL, NULL,
 					    "fsl,mpc5121-i2c-ctrl");
 	if (node_ctrl) {
 		ctrl = of_iomap(node_ctrl, 0);
 		if (ctrl) {
 			/* Interrupt enable bits for i2c-0/1/2: bit 24/26/28 */
 			pval = of_get_property(node, "reg", NULL);
 			idx = (*pval & 0xff) / 0x20;
 			setbits32(ctrl, 1 << (24 + idx * 2));
 			iounmap(ctrl);
 		}
 		of_node_put(node_ctrl);
 	}

 	/* The clock setup for the 52xx works also fine for the 512x */
 	mpc_i2c_setup_52xx(node, i2c, clock, prescaler);
 }
 #else /* CONFIG_PPC_MPC512x */
 static void mpc_i2c_setup_512x(struct device_node *node,
 					 struct mpc_i2c *i2c,
 					 u32 clock, u32 prescaler)
 {
 }
 #endif /* CONFIG_PPC_MPC512x */

 #ifdef CONFIG_FSL_SOC
 static const struct mpc_i2c_divider mpc_i2c_dividers_8xxx[] = {
 	{160, 0x0120}, {192, 0x0121}, {224, 0x0122}, {256, 0x0123},
 	{288, 0x0100}, {320, 0x0101}, {352, 0x0601}, {384, 0x0102},
 	{416, 0x0602}, {448, 0x0126}, {480, 0x0103}, {512, 0x0127},
 	{544, 0x0b03}, {576, 0x0104}, {608, 0x1603}, {640, 0x0105},
 	{672, 0x2003}, {704, 0x0b05}, {736, 0x2b03}, {768, 0x0106},
 	{800, 0x3603}, {832, 0x0b06}, {896, 0x012a}, {960, 0x0107},
 	{1024, 0x012b}, {1088, 0x1607}, {1152, 0x0108}, {1216, 0x2b07},
 	{1280, 0x0109}, {1408, 0x1609}, {1536, 0x010a}, {1664, 0x160a},
 	{1792, 0x012e}, {1920, 0x010b}, {2048, 0x012f}, {2176, 0x2b0b},
 	{2304, 0x010c}, {2560, 0x010d}, {2816, 0x2b0d}, {3072, 0x010e},
 	{3328, 0x2b0e}, {3584, 0x0132}, {3840, 0x010f}, {4096, 0x0133},
 	{4608, 0x0110}, {5120, 0x0111}, {6144, 0x0112}, {7168, 0x0136},
 	{7680, 0x0113}, {8192, 0x0137}, {9216, 0x0114}, {10240, 0x0115},
 	{12288, 0x0116}, {14336, 0x013a}, {15360, 0x0117}, {16384, 0x013b},
 	{18432, 0x0118}, {20480, 0x0119}, {24576, 0x011a}, {28672, 0x013e},
 	{30720, 0x011b}, {32768, 0x013f}, {36864, 0x011c}, {40960, 0x011d},
 	{49152, 0x011e}, {61440, 0x011f}
 };

 static u32 mpc_i2c_get_sec_cfg_8xxx(void)
 {
 	struct device_node *node = NULL;
 	u32 __iomem *reg;
 	u32 val = 0;

 	node = of_find_node_by_name(NULL, "global-utilities");
 	if (node) {
 		const u32 *prop = of_get_property(node, "reg", NULL);
 		if (prop) {
 			/*
 			 * Map and check POR Device Status Register 2
 			 * (PORDEVSR2) at 0xE0014
 			 */
 			reg = ioremap(get_immrbase() + *prop + 0x14, 0x4);
 			if (!reg)
 				printk(KERN_ERR
 				       "Error: couldn't map PORDEVSR2\n");
 			else
 				val = in_be32(reg) & 0x00000080; /* sec-cfg */
 			iounmap(reg);
 		}
 	}
 	if (node)
 		of_node_put(node);

 	return val;
 }

 static int mpc_i2c_get_fdr_8xxx(struct device_node *node, u32 clock,
 					  u32 prescaler, u32 *real_clk)
 {
 	const struct mpc_i2c_divider *div = NULL;
 	u32 divider;
 	int i;

 	if (clock == MPC_I2C_CLOCK_LEGACY) {
 		/* see below - default fdr = 0x1031 -> div = 16 * 3072 */
 		*real_clk = fsl_get_sys_freq() / prescaler / (16 * 3072);
 		return -EINVAL;
 	}

 	/* Determine proper divider value */
 	if (of_device_is_compatible(node, "fsl,mpc8544-i2c"))
 		prescaler = mpc_i2c_get_sec_cfg_8xxx() ? 3 : 2;
 	if (!prescaler)
 		prescaler = 1;

 	divider = fsl_get_sys_freq() / clock / prescaler;

 	pr_debug("I2C: src_clock=%d clock=%d divider=%d\n",
 		 fsl_get_sys_freq(), clock, divider);

 	/*
 	 * We want to choose an FDR/DFSR that generates an I2C bus speed that
 	 * is equal to or lower than the requested speed.
 	 */
 	for (i = 0; i < ARRAY_SIZE(mpc_i2c_dividers_8xxx); i++) {
 		div = &mpc_i2c_dividers_8xxx[i];
 		if (div->divider >= divider)
 			break;
 	}

 	*real_clk = fsl_get_sys_freq() / prescaler / div->divider;
 	return div ? (int)div->fdr : -EINVAL;
 }

 static void mpc_i2c_setup_8xxx(struct device_node *node,
 					 struct mpc_i2c *i2c,
 					 u32 clock, u32 prescaler)
 {
 	int ret, fdr;

 	if (clock == MPC_I2C_CLOCK_PRESERVE) {
 		dev_dbg(i2c->dev, "using dfsrr %d, fdr %d\n",
 			readb(i2c->base + MPC_I2C_DFSRR),
 			readb(i2c->base + MPC_I2C_FDR));
 		return;
 	}

 	ret = mpc_i2c_get_fdr_8xxx(node, clock, prescaler, &i2c->real_clk);
 	fdr = (ret >= 0) ? ret : 0x1031; /* backward compatibility */

 	writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
 	writeb((fdr >> 8) & 0xff, i2c->base + MPC_I2C_DFSRR);

 	if (ret >= 0)
 		dev_info(i2c->dev, "clock %d Hz (dfsrr=%d fdr=%d)\n",
 			 i2c->real_clk, fdr >> 8, fdr & 0xff);
 }

 #else /* !CONFIG_FSL_SOC */
 static void mpc_i2c_setup_8xxx(struct device_node *node,
 					 struct mpc_i2c *i2c,
 					 u32 clock, u32 prescaler)
 {
 }
 #endif /* CONFIG_FSL_SOC */

 static void mpc_i2c_start(struct mpc_i2c *i2c)
 {
 	/* Clear arbitration */
 	writeb(0, i2c->base + MPC_I2C_SR);
 	/* Start with MEN */
 	writeccr(i2c, CCR_MEN);
 }

 static void mpc_i2c_stop(struct mpc_i2c *i2c)
 {
 	writeccr(i2c, CCR_MEN);
 }

 static int mpc_write(struct mpc_i2c *i2c, int target,
 		     const u8 *data, int length, int restart)
 {
 	int i, result;
 	unsigned timeout = i2c->adap.timeout;
 	u32 flags = restart ? CCR_RSTA : 0;

 	/* Start as master */
 	writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
 	/* Write target byte */
 	writeb((target << 1), i2c->base + MPC_I2C_DR);

 	result = i2c_wait(i2c, timeout, 1);
 	if (result < 0)
 		return result;

 	for (i = 0; i < length; i++) {
 		/* Write data byte */
 		writeb(data[i], i2c->base + MPC_I2C_DR);

 		result = i2c_wait(i2c, timeout, 1);
 		if (result < 0)
 			return result;
 	}

 	return 0;
 }

 static int mpc_read(struct mpc_i2c *i2c, int target,
 		    u8 *data, int length, int restart, bool recv_len)
 {
 	unsigned timeout = i2c->adap.timeout;
 	int i, result;
 	u32 flags = restart ? CCR_RSTA : 0;

 	/* Switch to read - restart */
 	writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
 	/* Write target address byte - this time with the read flag set */
 	writeb((target << 1) | 1, i2c->base + MPC_I2C_DR);

 	result = i2c_wait(i2c, timeout, 1);
 	if (result < 0)
 		return result;

 	if (length) {
 		if (length == 1 && !recv_len)
 			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
 		else
 			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA);
 		/* Dummy read */
 		readb(i2c->base + MPC_I2C_DR);
 	}

 	for (i = 0; i < length; i++) {
 		u8 byte;

 		result = i2c_wait(i2c, timeout, 0);
 		if (result < 0)
 			return result;

 		/*
 		 * For block reads, we have to know the total length (1st byte)
 		 * before we can determine if we are done.
 		 */
 		if (i || !recv_len) {
 			/* Generate txack on next to last byte */
 			if (i == length - 2)
 				writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA
 					 | CCR_TXAK);
 			/* Do not generate stop on last byte */
 			if (i == length - 1)
 				writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA
 					 | CCR_MTX);
 		}

 		byte = readb(i2c->base + MPC_I2C_DR);

 		/*
 		 * Adjust length if first received byte is length.
 		 * The length is 1 length byte plus actually data length
 		 */
 		if (i == 0 && recv_len) {
 			if (byte == 0 || byte > I2C_SMBUS_BLOCK_MAX)
 				return -EPROTO;
 			length += byte;
 			/*
 			 * For block reads, generate txack here if data length
 			 * is 1 byte (total length is 2 bytes).
 			 */
 			if (length == 2)
 				writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA
 					 | CCR_TXAK);
 		}
 		data[i] = byte;
 	}

 	return length;
 }

 static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 {
 	struct i2c_msg *pmsg;
 	int i;
 	int ret = 0;
 	unsigned long orig_jiffies = jiffies;
 	struct mpc_i2c *i2c = i2c_get_adapdata(adap);

 	mpc_i2c_start(i2c);

 	/* Allow bus up to 1s to become not busy */
 	while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
 		if (signal_pending(current)) {
 			dev_dbg(i2c->dev, "Interrupted\n");
 			writeccr(i2c, 0);
 			return -EINTR;
 		}
 		if (time_after(jiffies, orig_jiffies + HZ)) {
 			u8 status = readb(i2c->base + MPC_I2C_SR);

 			dev_dbg(i2c->dev, "timeout\n");
 			if ((status & (CSR_MCF | CSR_MBB | CSR_RXAK)) != 0) {
 				writeb(status & ~CSR_MAL,
 				       i2c->base + MPC_I2C_SR);
 				mpc_i2c_fixup(i2c);
 			}
 			return -EIO;
 		}
 		schedule();
 	}

 	for (i = 0; ret >= 0 && i < num; i++) {
 		pmsg = &msgs[i];
 		dev_dbg(i2c->dev,
 			"Doing %s %d bytes to 0x%02x - %d of %d messages\n",
 			pmsg->flags & I2C_M_RD ? "read" : "write",
 			pmsg->len, pmsg->addr, i + 1, num);
 		if (pmsg->flags & I2C_M_RD) {
 			bool recv_len = pmsg->flags & I2C_M_RECV_LEN;

 			ret = mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i,
 				       recv_len);
 			if (recv_len && ret > 0)
 				pmsg->len = ret;
 		} else {
 			ret =
 			    mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
 		}
 	}
 	mpc_i2c_stop(i2c); /* Initiate STOP */
 	orig_jiffies = jiffies;
 	/* Wait until STOP is seen, allow up to 1 s */
 	while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
 		if (time_after(jiffies, orig_jiffies + HZ)) {
 			u8 status = readb(i2c->base + MPC_I2C_SR);

 			dev_dbg(i2c->dev, "timeout\n");
 			if ((status & (CSR_MCF | CSR_MBB | CSR_RXAK)) != 0) {
 				writeb(status & ~CSR_MAL,
 				       i2c->base + MPC_I2C_SR);
 				mpc_i2c_fixup(i2c);
 			}
 			return -EIO;
 		}
 		cond_resched();
 	}
 	return (ret < 0) ? ret : num;
 }

 static u32 mpc_functionality(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
 	  | I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
 }

 static const struct i2c_algorithm mpc_algo = {
 	.master_xfer = mpc_xfer,
 	.functionality = mpc_functionality,
 };

 static struct i2c_adapter mpc_ops = {
 	.owner = THIS_MODULE,
 	.name = "MPC adapter",
 	.algo = &mpc_algo,
 	.timeout = HZ,
 };

 static const struct of_device_id mpc_i2c_of_match[];
 static int fsl_i2c_probe(struct platform_device *op)
 {
 	const struct of_device_id *match;
 	struct mpc_i2c *i2c;
 	const u32 *prop;
 	u32 clock = MPC_I2C_CLOCK_LEGACY;
 	int result = 0;
 	int plen;

 	match = of_match_device(mpc_i2c_of_match, &op->dev);
 	if (!match)
 		return -EINVAL;

 	i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
 	if (!i2c)
 		return -ENOMEM;

 	i2c->dev = &op->dev; /* for debug and error output */

 	init_waitqueue_head(&i2c->queue);

 	i2c->base = of_iomap(op->dev.of_node, 0);
 	if (!i2c->base) {
 		dev_err(i2c->dev, "failed to map controller\n");
 		result = -ENOMEM;
 		goto fail_map;
 	}

 	i2c->irq = irq_of_parse_and_map(op->dev.of_node, 0);
 	if (i2c->irq) { /* no i2c->irq implies polling */
 		result = request_irq(i2c->irq, mpc_i2c_isr,
 				     IRQF_SHARED, "i2c-mpc", i2c);
 		if (result < 0) {
 			dev_err(i2c->dev, "failed to attach interrupt\n");
 			goto fail_request;
 		}
 	}

 	if (of_get_property(op->dev.of_node, "fsl,preserve-clocking", NULL)) {
 		clock = MPC_I2C_CLOCK_PRESERVE;
 	} else {
 		prop = of_get_property(op->dev.of_node, "clock-frequency",
 					&plen);
 		if (prop && plen == sizeof(u32))
 			clock = *prop;
 	}

 	if (match->data) {
 		const struct mpc_i2c_data *data = match->data;
 		data->setup(op->dev.of_node, i2c, clock, data->prescaler);
 	} else {
 		/* Backwards compatibility */
 		if (of_get_property(op->dev.of_node, "dfsrr", NULL))
 			mpc_i2c_setup_8xxx(op->dev.of_node, i2c, clock, 0);
 	}

 	prop = of_get_property(op->dev.of_node, "fsl,timeout", &plen);
 	if (prop && plen == sizeof(u32)) {
 		mpc_ops.timeout = *prop * HZ / 1000000;
 		if (mpc_ops.timeout < 5)
 			mpc_ops.timeout = 5;
 	}
 	dev_info(i2c->dev, "timeout %u us\n", mpc_ops.timeout * 1000000 / HZ);

 	dev_set_drvdata(&op->dev, i2c);

 	i2c->adap = mpc_ops;
 	i2c_set_adapdata(&i2c->adap, i2c);
 	i2c->adap.dev.parent = &op->dev;
 	i2c->adap.dev.of_node = of_node_get(op->dev.of_node);

 	result = i2c_add_adapter(&i2c->adap);
 	if (result < 0) {
 		dev_err(i2c->dev, "failed to add adapter\n");
 		goto fail_add;
 	}
 	of_i2c_register_devices(&i2c->adap);

 	return result;

  fail_add:
 	free_irq(i2c->irq, i2c);
  fail_request:
 	irq_dispose_mapping(i2c->irq);
 	iounmap(i2c->base);
  fail_map:
 	kfree(i2c);
 	return result;
 };

 static int fsl_i2c_remove(struct platform_device *op)
 {
 	struct mpc_i2c *i2c = dev_get_drvdata(&op->dev);

 	i2c_del_adapter(&i2c->adap);

 	if (i2c->irq)
 		free_irq(i2c->irq, i2c);

 	irq_dispose_mapping(i2c->irq);
 	iounmap(i2c->base);
 	kfree(i2c);
 	return 0;
 };

 #ifdef CONFIG_PM
 static int mpc_i2c_suspend(struct device *dev)
 {
 	struct mpc_i2c *i2c = dev_get_drvdata(dev);

 	i2c->fdr = readb(i2c->base + MPC_I2C_FDR);
 	i2c->dfsrr = readb(i2c->base + MPC_I2C_DFSRR);

 	return 0;
 }

 static int mpc_i2c_resume(struct device *dev)
 {
 	struct mpc_i2c *i2c = dev_get_drvdata(dev);

 	writeb(i2c->fdr, i2c->base + MPC_I2C_FDR);
 	writeb(i2c->dfsrr, i2c->base + MPC_I2C_DFSRR);

 	return 0;
 }

 SIMPLE_DEV_PM_OPS(mpc_i2c_pm_ops, mpc_i2c_suspend, mpc_i2c_resume);
 #endif

 static const struct mpc_i2c_data mpc_i2c_data_512x = {
 	.setup = mpc_i2c_setup_512x,
 };

 static const struct mpc_i2c_data mpc_i2c_data_52xx = {
 	.setup = mpc_i2c_setup_52xx,
 };

 static const struct mpc_i2c_data mpc_i2c_data_8313 = {
 	.setup = mpc_i2c_setup_8xxx,
 };

 static const struct mpc_i2c_data mpc_i2c_data_8543 = {
 	.setup = mpc_i2c_setup_8xxx,
 	.prescaler = 2,
 };

 static const struct mpc_i2c_data mpc_i2c_data_8544 = {
 	.setup = mpc_i2c_setup_8xxx,
 	.prescaler = 3,
 };

 static const struct of_device_id mpc_i2c_of_match[] = {
 	{.compatible = "mpc5200-i2c", .data = &mpc_i2c_data_52xx, },
 	{.compatible = "fsl,mpc5200b-i2c", .data = &mpc_i2c_data_52xx, },
 	{.compatible = "fsl,mpc5200-i2c", .data = &mpc_i2c_data_52xx, },
 	{.compatible = "fsl,mpc5121-i2c", .data = &mpc_i2c_data_512x, },
 	{.compatible = "fsl,mpc8313-i2c", .data = &mpc_i2c_data_8313, },
 	{.compatible = "fsl,mpc8543-i2c", .data = &mpc_i2c_data_8543, },
 	{.compatible = "fsl,mpc8544-i2c", .data = &mpc_i2c_data_8544, },
 	/* Backward compatibility */
 	{.compatible = "fsl-i2c", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, mpc_i2c_of_match);

 /* Structure for a device driver */
 static struct platform_driver mpc_i2c_driver = {
 	.probe		= fsl_i2c_probe,
 	.remove		= fsl_i2c_remove,
 	.driver = {
 		.owner = THIS_MODULE,
 		.name = DRV_NAME,
 		.of_match_table = mpc_i2c_of_match,
 #ifdef CONFIG_PM
 		.pm = &mpc_i2c_pm_ops,
 #endif
 	},
 };

 module_platform_driver(mpc_i2c_driver);

 MODULE_AUTHOR("Adrian Cox <adrian@humboldt.co.uk>");
 MODULE_DESCRIPTION("I2C-Bus adapter for MPC107 bridge and "
 		   "MPC824x/83xx/85xx/86xx/512x/52xx processors");
 MODULE_LICENSE("GPL");
	/*
	* (C) Copyright 2003-2004
	* Humboldt Solutions Ltd, adrian@humboldt.co.uk.

	* This is a combined i2c adapter and algorithm driver for the
	* MPC107/Tsi107 PowerPC northbridge and processors that include
	* the same I2C unit (8240, 8245, 85xx).
	*
	* Release 0.8
	*
	* 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.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/sched.h>
	#include <linux/init.h>
	#include <linux/of_platform.h>
	#include <linux/of_i2c.h>
	#include <linux/slab.h>

	#include <linux/io.h>
	#include <linux/fsl_devices.h>
	#include <linux/i2c.h>
	#include <linux/interrupt.h>
	#include <linux/delay.h>

	#include <asm/mpc52xx.h>
	#include <sysdev/fsl_soc.h>

	#define DRV_NAME "mpc-i2c"

	#define MPC_I2C_CLOCK_LEGACY 0
	#define MPC_I2C_CLOCK_PRESERVE (~0U)

	#define MPC_I2C_FDR 0x04
	#define MPC_I2C_CR 0x08
	#define MPC_I2C_SR 0x0c
	#define MPC_I2C_DR 0x10
	#define MPC_I2C_DFSRR 0x14

	#define CCR_MEN 0x80
	#define CCR_MIEN 0x40
	#define CCR_MSTA 0x20
	#define CCR_MTX 0x10
	#define CCR_TXAK 0x08
	#define CCR_RSTA 0x04

	#define CSR_MCF 0x80
	#define CSR_MAAS 0x40
	#define CSR_MBB 0x20
	#define CSR_MAL 0x10
	#define CSR_SRW 0x04
	#define CSR_MIF 0x02
	#define CSR_RXAK 0x01

	struct mpc_i2c {
	struct device *dev;
	void __iomem *base;
	u32 interrupt;
	wait_queue_head_t queue;
	struct i2c_adapter adap;
	int irq;
	u32 real_clk;
	#ifdef CONFIG_PM
	u8 fdr, dfsrr;
	#endif
	};

	struct mpc_i2c_divider {
	u16 divider;
	u16 fdr; /* including dfsrr */
	};

	struct mpc_i2c_data {
	void (setup)(struct device_node node, struct mpc_i2c *i2c,
	u32 clock, u32 prescaler);
	u32 prescaler;
	};

	static inline void writeccr(struct mpc_i2c *i2c, u32 x)
	{
	writeb(x, i2c->base + MPC_I2C_CR);
	}

	static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
	{
	struct mpc_i2c *i2c = dev_id;
	if (readb(i2c->base + MPC_I2C_SR) & CSR_MIF) {
	/* Read again to allow register to stabilise */
	i2c->interrupt = readb(i2c->base + MPC_I2C_SR);
	writeb(0, i2c->base + MPC_I2C_SR);
	wake_up(&i2c->queue);
	}
	return IRQ_HANDLED;
	}

	/* Sometimes 9th clock pulse isn't generated, and slave doesn't release
	* the bus, because it wants to send ACK.
	* Following sequence of enabling/disabling and sending start/stop generates
	* the 9 pulses, so it's all OK.
	*/
	static void mpc_i2c_fixup(struct mpc_i2c *i2c)
	{
	int k;
	u32 delay_val = 1000000 / i2c->real_clk + 1;

	if (delay_val < 2)
	delay_val = 2;

	for (k = 9; k; k--) {
	writeccr(i2c, 0);
	writeccr(i2c, CCR_MSTA \| CCR_MTX \| CCR_MEN);
	udelay(delay_val);
	writeccr(i2c, CCR_MEN);
	udelay(delay_val << 1);
	}
	}

	static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
	{
	unsigned long orig_jiffies = jiffies;
	u32 x;
	int result = 0;

	if (!i2c->irq) {
	while (!(readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
	schedule();
	if (time_after(jiffies, orig_jiffies + timeout)) {
	dev_dbg(i2c->dev, "timeout\n");
	writeccr(i2c, 0);
	result = -EIO;
	break;
	}
	}
	x = readb(i2c->base + MPC_I2C_SR);
	writeb(0, i2c->base + MPC_I2C_SR);
	} else {
	/* Interrupt mode */
	result = wait_event_timeout(i2c->queue,
	(i2c->interrupt & CSR_MIF), timeout);

	if (unlikely(!(i2c->interrupt & CSR_MIF))) {
	dev_dbg(i2c->dev, "wait timeout\n");
	writeccr(i2c, 0);
	result = -ETIMEDOUT;
	}

	x = i2c->interrupt;
	i2c->interrupt = 0;
	}

	if (result < 0)
	return result;

	if (!(x & CSR_MCF)) {
	dev_dbg(i2c->dev, "unfinished\n");
	return -EIO;
	}

	if (x & CSR_MAL) {
	dev_dbg(i2c->dev, "MAL\n");
	return -EIO;
	}

	if (writing && (x & CSR_RXAK)) {
	dev_dbg(i2c->dev, "No RXAK\n");
	/* generate stop */
	writeccr(i2c, CCR_MEN);
	return -EIO;
	}
	return 0;
	}

	#if defined(CONFIG_PPC_MPC52xx) \|\| defined(CONFIG_PPC_MPC512x)
	static const struct mpc_i2c_divider mpc_i2c_dividers_52xx[] = {
	{20, 0x20}, {22, 0x21}, {24, 0x22}, {26, 0x23},
	{28, 0x24}, {30, 0x01}, {32, 0x25}, {34, 0x02},
	{36, 0x26}, {40, 0x27}, {44, 0x04}, {48, 0x28},
	{52, 0x63}, {56, 0x29}, {60, 0x41}, {64, 0x2a},
	{68, 0x07}, {72, 0x2b}, {80, 0x2c}, {88, 0x09},
	{96, 0x2d}, {104, 0x0a}, {112, 0x2e}, {120, 0x81},
	{128, 0x2f}, {136, 0x47}, {144, 0x0c}, {160, 0x30},
	{176, 0x49}, {192, 0x31}, {208, 0x4a}, {224, 0x32},
	{240, 0x0f}, {256, 0x33}, {272, 0x87}, {288, 0x10},
	{320, 0x34}, {352, 0x89}, {384, 0x35}, {416, 0x8a},
	{448, 0x36}, {480, 0x13}, {512, 0x37}, {576, 0x14},
	{640, 0x38}, {768, 0x39}, {896, 0x3a}, {960, 0x17},
	{1024, 0x3b}, {1152, 0x18}, {1280, 0x3c}, {1536, 0x3d},
	{1792, 0x3e}, {1920, 0x1b}, {2048, 0x3f}, {2304, 0x1c},
	{2560, 0x1d}, {3072, 0x1e}, {3584, 0x7e}, {3840, 0x1f},
	{4096, 0x7f}, {4608, 0x5c}, {5120, 0x5d}, {6144, 0x5e},
	{7168, 0xbe}, {7680, 0x5f}, {8192, 0xbf}, {9216, 0x9c},
	{10240, 0x9d}, {12288, 0x9e}, {15360, 0x9f}
	};

	static int mpc_i2c_get_fdr_52xx(struct device_node *node, u32 clock,
	int prescaler, u32 *real_clk)
	{
	const struct mpc_i2c_divider *div = NULL;
	unsigned int pvr = mfspr(SPRN_PVR);
	u32 divider;
	int i;

	if (clock == MPC_I2C_CLOCK_LEGACY) {
	/* see below - default fdr = 0x3f -> div = 2048 */
	*real_clk = mpc5xxx_get_bus_frequency(node) / 2048;
	return -EINVAL;
	}

	/* Determine divider value */
	divider = mpc5xxx_get_bus_frequency(node) / clock;

	/*
	* We want to choose an FDR/DFSR that generates an I2C bus speed that
	* is equal to or lower than the requested speed.
	*/
	for (i = 0; i < ARRAY_SIZE(mpc_i2c_dividers_52xx); i++) {
	div = &mpc_i2c_dividers_52xx[i];
	/* Old MPC5200 rev A CPUs do not support the high bits */
	if (div->fdr & 0xc0 && pvr == 0x80822011)
	continue;
	if (div->divider >= divider)
	break;
	}

	*real_clk = mpc5xxx_get_bus_frequency(node) / div->divider;
	return (int)div->fdr;
	}

	static void mpc_i2c_setup_52xx(struct device_node *node,
	struct mpc_i2c *i2c,
	u32 clock, u32 prescaler)
	{
	int ret, fdr;

	if (clock == MPC_I2C_CLOCK_PRESERVE) {
	dev_dbg(i2c->dev, "using fdr %d\n",
	readb(i2c->base + MPC_I2C_FDR));
	return;
	}

	ret = mpc_i2c_get_fdr_52xx(node, clock, prescaler, &i2c->real_clk);
	fdr = (ret >= 0) ? ret : 0x3f; /* backward compatibility */

	writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);

	if (ret >= 0)
	dev_info(i2c->dev, "clock %u Hz (fdr=%d)\n", i2c->real_clk,
	fdr);
	}
	#else /* !(CONFIG_PPC_MPC52xx \|\| CONFIG_PPC_MPC512x) */
	static void mpc_i2c_setup_52xx(struct device_node *node,
	struct mpc_i2c *i2c,
	u32 clock, u32 prescaler)
	{
	}
	#endif /* CONFIG_PPC_MPC52xx \|\| CONFIG_PPC_MPC512x */

	#ifdef CONFIG_PPC_MPC512x
	static void mpc_i2c_setup_512x(struct device_node *node,
	struct mpc_i2c *i2c,
	u32 clock, u32 prescaler)
	{
	struct device_node *node_ctrl;
	void __iomem *ctrl;
	const u32 *pval;
	u32 idx;

	/* Enable I2C interrupts for mpc5121 */
	node_ctrl = of_find_compatible_node(NULL, NULL,
	"fsl,mpc5121-i2c-ctrl");
	if (node_ctrl) {
	ctrl = of_iomap(node_ctrl, 0);
	if (ctrl) {
	/* Interrupt enable bits for i2c-0/1/2: bit 24/26/28 */
	pval = of_get_property(node, "reg", NULL);
	idx = (*pval & 0xff) / 0x20;
	setbits32(ctrl, 1 << (24 + idx * 2));
	iounmap(ctrl);
	}
	of_node_put(node_ctrl);
	}

	/* The clock setup for the 52xx works also fine for the 512x */
	mpc_i2c_setup_52xx(node, i2c, clock, prescaler);
	}
	#else /* CONFIG_PPC_MPC512x */
	static void mpc_i2c_setup_512x(struct device_node *node,
	struct mpc_i2c *i2c,
	u32 clock, u32 prescaler)
	{
	}
	#endif /* CONFIG_PPC_MPC512x */

	#ifdef CONFIG_FSL_SOC
	static const struct mpc_i2c_divider mpc_i2c_dividers_8xxx[] = {
	{160, 0x0120}, {192, 0x0121}, {224, 0x0122}, {256, 0x0123},
	{288, 0x0100}, {320, 0x0101}, {352, 0x0601}, {384, 0x0102},
	{416, 0x0602}, {448, 0x0126}, {480, 0x0103}, {512, 0x0127},
	{544, 0x0b03}, {576, 0x0104}, {608, 0x1603}, {640, 0x0105},
	{672, 0x2003}, {704, 0x0b05}, {736, 0x2b03}, {768, 0x0106},
	{800, 0x3603}, {832, 0x0b06}, {896, 0x012a}, {960, 0x0107},
	{1024, 0x012b}, {1088, 0x1607}, {1152, 0x0108}, {1216, 0x2b07},
	{1280, 0x0109}, {1408, 0x1609}, {1536, 0x010a}, {1664, 0x160a},
	{1792, 0x012e}, {1920, 0x010b}, {2048, 0x012f}, {2176, 0x2b0b},
	{2304, 0x010c}, {2560, 0x010d}, {2816, 0x2b0d}, {3072, 0x010e},
	{3328, 0x2b0e}, {3584, 0x0132}, {3840, 0x010f}, {4096, 0x0133},
	{4608, 0x0110}, {5120, 0x0111}, {6144, 0x0112}, {7168, 0x0136},
	{7680, 0x0113}, {8192, 0x0137}, {9216, 0x0114}, {10240, 0x0115},
	{12288, 0x0116}, {14336, 0x013a}, {15360, 0x0117}, {16384, 0x013b},
	{18432, 0x0118}, {20480, 0x0119}, {24576, 0x011a}, {28672, 0x013e},
	{30720, 0x011b}, {32768, 0x013f}, {36864, 0x011c}, {40960, 0x011d},
	{49152, 0x011e}, {61440, 0x011f}
	};

	static u32 mpc_i2c_get_sec_cfg_8xxx(void)
	{
	struct device_node *node = NULL;
	u32 __iomem *reg;
	u32 val = 0;

	node = of_find_node_by_name(NULL, "global-utilities");
	if (node) {
	const u32 *prop = of_get_property(node, "reg", NULL);
	if (prop) {
	/*
	* Map and check POR Device Status Register 2
	* (PORDEVSR2) at 0xE0014
	*/
	reg = ioremap(get_immrbase() + *prop + 0x14, 0x4);
	if (!reg)
	printk(KERN_ERR
	"Error: couldn't map PORDEVSR2\n");
	else
	val = in_be32(reg) & 0x00000080; /* sec-cfg */
	iounmap(reg);
	}
	}
	if (node)
	of_node_put(node);

	return val;
	}

	static int mpc_i2c_get_fdr_8xxx(struct device_node *node, u32 clock,
	u32 prescaler, u32 *real_clk)
	{
	const struct mpc_i2c_divider *div = NULL;
	u32 divider;
	int i;

	if (clock == MPC_I2C_CLOCK_LEGACY) {
	/* see below - default fdr = 0x1031 -> div = 16 * 3072 */
	real_clk = fsl_get_sys_freq() / prescaler / (16 3072);
	return -EINVAL;
	}

	/* Determine proper divider value */
	if (of_device_is_compatible(node, "fsl,mpc8544-i2c"))
	prescaler = mpc_i2c_get_sec_cfg_8xxx() ? 3 : 2;
	if (!prescaler)
	prescaler = 1;

	divider = fsl_get_sys_freq() / clock / prescaler;

	pr_debug("I2C: src_clock=%d clock=%d divider=%d\n",
	fsl_get_sys_freq(), clock, divider);

	/*
	* We want to choose an FDR/DFSR that generates an I2C bus speed that
	* is equal to or lower than the requested speed.
	*/
	for (i = 0; i < ARRAY_SIZE(mpc_i2c_dividers_8xxx); i++) {
	div = &mpc_i2c_dividers_8xxx[i];
	if (div->divider >= divider)
	break;
	}

	*real_clk = fsl_get_sys_freq() / prescaler / div->divider;
	return div ? (int)div->fdr : -EINVAL;
	}

	static void mpc_i2c_setup_8xxx(struct device_node *node,
	struct mpc_i2c *i2c,
	u32 clock, u32 prescaler)
	{
	int ret, fdr;

	if (clock == MPC_I2C_CLOCK_PRESERVE) {
	dev_dbg(i2c->dev, "using dfsrr %d, fdr %d\n",
	readb(i2c->base + MPC_I2C_DFSRR),
	readb(i2c->base + MPC_I2C_FDR));
	return;
	}

	ret = mpc_i2c_get_fdr_8xxx(node, clock, prescaler, &i2c->real_clk);
	fdr = (ret >= 0) ? ret : 0x1031; /* backward compatibility */

	writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
	writeb((fdr >> 8) & 0xff, i2c->base + MPC_I2C_DFSRR);

	if (ret >= 0)
	dev_info(i2c->dev, "clock %d Hz (dfsrr=%d fdr=%d)\n",
	i2c->real_clk, fdr >> 8, fdr & 0xff);
	}

	#else /* !CONFIG_FSL_SOC */
	static void mpc_i2c_setup_8xxx(struct device_node *node,
	struct mpc_i2c *i2c,
	u32 clock, u32 prescaler)
	{
	}
	#endif /* CONFIG_FSL_SOC */

	static void mpc_i2c_start(struct mpc_i2c *i2c)
	{
	/* Clear arbitration */
	writeb(0, i2c->base + MPC_I2C_SR);
	/* Start with MEN */
	writeccr(i2c, CCR_MEN);
	}

	static void mpc_i2c_stop(struct mpc_i2c *i2c)
	{
	writeccr(i2c, CCR_MEN);
	}

	static int mpc_write(struct mpc_i2c *i2c, int target,
	const u8 *data, int length, int restart)
	{
	int i, result;
	unsigned timeout = i2c->adap.timeout;
	u32 flags = restart ? CCR_RSTA : 0;

	/* Start as master */
	writeccr(i2c, CCR_MIEN \| CCR_MEN \| CCR_MSTA \| CCR_MTX \| flags);
	/* Write target byte */
	writeb((target << 1), i2c->base + MPC_I2C_DR);

	result = i2c_wait(i2c, timeout, 1);
	if (result < 0)
	return result;

	for (i = 0; i < length; i++) {
	/* Write data byte */
	writeb(data[i], i2c->base + MPC_I2C_DR);

	result = i2c_wait(i2c, timeout, 1);
	if (result < 0)
	return result;
	}

	return 0;
	}

	static int mpc_read(struct mpc_i2c *i2c, int target,
	u8 *data, int length, int restart, bool recv_len)
	{
	unsigned timeout = i2c->adap.timeout;
	int i, result;
	u32 flags = restart ? CCR_RSTA : 0;

	/* Switch to read - restart */
	writeccr(i2c, CCR_MIEN \| CCR_MEN \| CCR_MSTA \| CCR_MTX \| flags);
	/* Write target address byte - this time with the read flag set */
	writeb((target << 1) \| 1, i2c->base + MPC_I2C_DR);

	result = i2c_wait(i2c, timeout, 1);
	if (result < 0)
	return result;

	if (length) {
	if (length == 1 && !recv_len)
	writeccr(i2c, CCR_MIEN \| CCR_MEN \| CCR_MSTA \| CCR_TXAK);
	else
	writeccr(i2c, CCR_MIEN \| CCR_MEN \| CCR_MSTA);
	/* Dummy read */
	readb(i2c->base + MPC_I2C_DR);
	}

	for (i = 0; i < length; i++) {
	u8 byte;

	result = i2c_wait(i2c, timeout, 0);
	if (result < 0)
	return result;

	/*
	* For block reads, we have to know the total length (1st byte)
	* before we can determine if we are done.
	*/
	if (i \|\| !recv_len) {
	/* Generate txack on next to last byte */
	if (i == length - 2)
	writeccr(i2c, CCR_MIEN \| CCR_MEN \| CCR_MSTA
	\| CCR_TXAK);
	/* Do not generate stop on last byte */
	if (i == length - 1)
	writeccr(i2c, CCR_MIEN \| CCR_MEN \| CCR_MSTA
	\| CCR_MTX);
	}

	byte = readb(i2c->base + MPC_I2C_DR);

	/*
	* Adjust length if first received byte is length.
	* The length is 1 length byte plus actually data length
	*/
	if (i == 0 && recv_len) {
	if (byte == 0 \|\| byte > I2C_SMBUS_BLOCK_MAX)
	return -EPROTO;
	length += byte;
	/*
	* For block reads, generate txack here if data length
	* is 1 byte (total length is 2 bytes).
	*/
	if (length == 2)
	writeccr(i2c, CCR_MIEN \| CCR_MEN \| CCR_MSTA
	\| CCR_TXAK);
	}
	data[i] = byte;
	}

	return length;
	}

	static int mpc_xfer(struct i2c_adapter adap, struct i2c_msg msgs, int num)
	{
	struct i2c_msg *pmsg;
	int i;
	int ret = 0;
	unsigned long orig_jiffies = jiffies;
	struct mpc_i2c *i2c = i2c_get_adapdata(adap);

	mpc_i2c_start(i2c);

	/* Allow bus up to 1s to become not busy */
	while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
	if (signal_pending(current)) {
	dev_dbg(i2c->dev, "Interrupted\n");
	writeccr(i2c, 0);
	return -EINTR;
	}
	if (time_after(jiffies, orig_jiffies + HZ)) {
	u8 status = readb(i2c->base + MPC_I2C_SR);

	dev_dbg(i2c->dev, "timeout\n");
	if ((status & (CSR_MCF \| CSR_MBB \| CSR_RXAK)) != 0) {
	writeb(status & ~CSR_MAL,
	i2c->base + MPC_I2C_SR);
	mpc_i2c_fixup(i2c);
	}
	return -EIO;
	}
	schedule();
	}

	for (i = 0; ret >= 0 && i < num; i++) {
	pmsg = &msgs[i];
	dev_dbg(i2c->dev,
	"Doing %s %d bytes to 0x%02x - %d of %d messages\n",
	pmsg->flags & I2C_M_RD ? "read" : "write",
	pmsg->len, pmsg->addr, i + 1, num);
	if (pmsg->flags & I2C_M_RD) {
	bool recv_len = pmsg->flags & I2C_M_RECV_LEN;

	ret = mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i,
	recv_len);
	if (recv_len && ret > 0)
	pmsg->len = ret;
	} else {
	ret =
	mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
	}
	}
	mpc_i2c_stop(i2c); /* Initiate STOP */
	orig_jiffies = jiffies;
	/* Wait until STOP is seen, allow up to 1 s */
	while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
	if (time_after(jiffies, orig_jiffies + HZ)) {
	u8 status = readb(i2c->base + MPC_I2C_SR);

	dev_dbg(i2c->dev, "timeout\n");
	if ((status & (CSR_MCF \| CSR_MBB \| CSR_RXAK)) != 0) {
	writeb(status & ~CSR_MAL,
	i2c->base + MPC_I2C_SR);
	mpc_i2c_fixup(i2c);
	}
	return -EIO;
	}
	cond_resched();
	}
	return (ret < 0) ? ret : num;
	}

	static u32 mpc_functionality(struct i2c_adapter *adap)
	{
	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL
	\| I2C_FUNC_SMBUS_READ_BLOCK_DATA \| I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
	}

	static const struct i2c_algorithm mpc_algo = {
	.master_xfer = mpc_xfer,
	.functionality = mpc_functionality,
	};

	static struct i2c_adapter mpc_ops = {
	.owner = THIS_MODULE,
	.name = "MPC adapter",
	.algo = &mpc_algo,
	.timeout = HZ,
	};

	static const struct of_device_id mpc_i2c_of_match[];
	static int fsl_i2c_probe(struct platform_device *op)
	{
	const struct of_device_id *match;
	struct mpc_i2c *i2c;
	const u32 *prop;
	u32 clock = MPC_I2C_CLOCK_LEGACY;
	int result = 0;
	int plen;

	match = of_match_device(mpc_i2c_of_match, &op->dev);
	if (!match)
	return -EINVAL;

	i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
	if (!i2c)
	return -ENOMEM;

	i2c->dev = &op->dev; /* for debug and error output */

	init_waitqueue_head(&i2c->queue);

	i2c->base = of_iomap(op->dev.of_node, 0);
	if (!i2c->base) {
	dev_err(i2c->dev, "failed to map controller\n");
	result = -ENOMEM;
	goto fail_map;
	}

	i2c->irq = irq_of_parse_and_map(op->dev.of_node, 0);
	if (i2c->irq) { /* no i2c->irq implies polling */
	result = request_irq(i2c->irq, mpc_i2c_isr,
	IRQF_SHARED, "i2c-mpc", i2c);
	if (result < 0) {
	dev_err(i2c->dev, "failed to attach interrupt\n");
	goto fail_request;
	}
	}

	if (of_get_property(op->dev.of_node, "fsl,preserve-clocking", NULL)) {
	clock = MPC_I2C_CLOCK_PRESERVE;
	} else {
	prop = of_get_property(op->dev.of_node, "clock-frequency",
	&plen);
	if (prop && plen == sizeof(u32))
	clock = *prop;
	}

	if (match->data) {
	const struct mpc_i2c_data *data = match->data;
	data->setup(op->dev.of_node, i2c, clock, data->prescaler);
	} else {
	/* Backwards compatibility */
	if (of_get_property(op->dev.of_node, "dfsrr", NULL))
	mpc_i2c_setup_8xxx(op->dev.of_node, i2c, clock, 0);
	}

	prop = of_get_property(op->dev.of_node, "fsl,timeout", &plen);
	if (prop && plen == sizeof(u32)) {
	mpc_ops.timeout = prop HZ / 1000000;
	if (mpc_ops.timeout < 5)
	mpc_ops.timeout = 5;
	}
	dev_info(i2c->dev, "timeout %u us\n", mpc_ops.timeout * 1000000 / HZ);

	dev_set_drvdata(&op->dev, i2c);

	i2c->adap = mpc_ops;
	i2c_set_adapdata(&i2c->adap, i2c);
	i2c->adap.dev.parent = &op->dev;
	i2c->adap.dev.of_node = of_node_get(op->dev.of_node);

	result = i2c_add_adapter(&i2c->adap);
	if (result < 0) {
	dev_err(i2c->dev, "failed to add adapter\n");
	goto fail_add;
	}
	of_i2c_register_devices(&i2c->adap);

	return result;

	fail_add:
	free_irq(i2c->irq, i2c);
	fail_request:
	irq_dispose_mapping(i2c->irq);
	iounmap(i2c->base);
	fail_map:
	kfree(i2c);
	return result;
	};

	static int fsl_i2c_remove(struct platform_device *op)
	{
	struct mpc_i2c *i2c = dev_get_drvdata(&op->dev);

	i2c_del_adapter(&i2c->adap);

	if (i2c->irq)
	free_irq(i2c->irq, i2c);

	irq_dispose_mapping(i2c->irq);
	iounmap(i2c->base);
	kfree(i2c);
	return 0;
	};

	#ifdef CONFIG_PM
	static int mpc_i2c_suspend(struct device *dev)
	{
	struct mpc_i2c *i2c = dev_get_drvdata(dev);

	i2c->fdr = readb(i2c->base + MPC_I2C_FDR);
	i2c->dfsrr = readb(i2c->base + MPC_I2C_DFSRR);

	return 0;
	}

	static int mpc_i2c_resume(struct device *dev)
	{
	struct mpc_i2c *i2c = dev_get_drvdata(dev);

	writeb(i2c->fdr, i2c->base + MPC_I2C_FDR);
	writeb(i2c->dfsrr, i2c->base + MPC_I2C_DFSRR);

	return 0;
	}

	SIMPLE_DEV_PM_OPS(mpc_i2c_pm_ops, mpc_i2c_suspend, mpc_i2c_resume);
	#endif

	static const struct mpc_i2c_data mpc_i2c_data_512x = {
	.setup = mpc_i2c_setup_512x,
	};

	static const struct mpc_i2c_data mpc_i2c_data_52xx = {
	.setup = mpc_i2c_setup_52xx,
	};

	static const struct mpc_i2c_data mpc_i2c_data_8313 = {
	.setup = mpc_i2c_setup_8xxx,
	};

	static const struct mpc_i2c_data mpc_i2c_data_8543 = {
	.setup = mpc_i2c_setup_8xxx,
	.prescaler = 2,
	};

	static const struct mpc_i2c_data mpc_i2c_data_8544 = {
	.setup = mpc_i2c_setup_8xxx,
	.prescaler = 3,
	};

	static const struct of_device_id mpc_i2c_of_match[] = {
	{.compatible = "mpc5200-i2c", .data = &mpc_i2c_data_52xx, },
	{.compatible = "fsl,mpc5200b-i2c", .data = &mpc_i2c_data_52xx, },
	{.compatible = "fsl,mpc5200-i2c", .data = &mpc_i2c_data_52xx, },
	{.compatible = "fsl,mpc5121-i2c", .data = &mpc_i2c_data_512x, },
	{.compatible = "fsl,mpc8313-i2c", .data = &mpc_i2c_data_8313, },
	{.compatible = "fsl,mpc8543-i2c", .data = &mpc_i2c_data_8543, },
	{.compatible = "fsl,mpc8544-i2c", .data = &mpc_i2c_data_8544, },
	/* Backward compatibility */
	{.compatible = "fsl-i2c", },
	{},
	};
	MODULE_DEVICE_TABLE(of, mpc_i2c_of_match);

	/* Structure for a device driver */
	static struct platform_driver mpc_i2c_driver = {
	.probe = fsl_i2c_probe,
	.remove = fsl_i2c_remove,
	.driver = {
	.owner = THIS_MODULE,
	.name = DRV_NAME,
	.of_match_table = mpc_i2c_of_match,
	#ifdef CONFIG_PM
	.pm = &mpc_i2c_pm_ops,
	#endif
	},
	};

	module_platform_driver(mpc_i2c_driver);

	MODULE_AUTHOR("Adrian Cox <adrian@humboldt.co.uk>");
	MODULE_DESCRIPTION("I2C-Bus adapter for MPC107 bridge and "
	"MPC824x/83xx/85xx/86xx/512x/52xx processors");
	MODULE_LICENSE("GPL");