i2c: bcm-kona: Introduce Broadcom I2C Driver

Introduce support for Broadcom Serial Controller (BSC) I2C bus found
in the Kona family of Mobile SoCs.  FIFO hardware is utilized but only
standard mode (100kHz), fast mode (400kHz), fast mode plus (1MHz), and
I2C high-speed (3.4 MHz) bus speeds are supported.

Signed-off-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Matt Porter <matt.porter@linaro.org>
Reviewed-by: Markus Mayer <markus.mayer@linaro.org>
[wsa: fixed Kconfig sorting, squashed broken out patches into one]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

1 files changed, 908 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-bcm-kona.c b/drivers/i2c/busses/i2c-bcm-kona.c
new file mode 100644
index 000000000000..7b7b7622b0d1
--- /dev/null
+++ b/drivers/i2c/busses/i2c-bcm-kona.c
@@ -0,0 +1,908 @@
+/*
+ * Copyright (C) 2013 Broadcom Corporation
+ *
+ * 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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/slab.h>
+
+/* Hardware register offsets and field defintions */
+#define CS_OFFSET				0x00000020
+#define CS_ACK_SHIFT				3
+#define CS_ACK_MASK				0x00000008
+#define CS_ACK_CMD_GEN_START			0x00000000
+#define CS_ACK_CMD_GEN_RESTART			0x00000001
+#define CS_CMD_SHIFT				1
+#define CS_CMD_CMD_NO_ACTION			0x00000000
+#define CS_CMD_CMD_START_RESTART		0x00000001
+#define CS_CMD_CMD_STOP				0x00000002
+#define CS_EN_SHIFT				0
+#define CS_EN_CMD_ENABLE_BSC			0x00000001
+
+#define TIM_OFFSET				0x00000024
+#define TIM_PRESCALE_SHIFT			6
+#define TIM_P_SHIFT				3
+#define TIM_NO_DIV_SHIFT			2
+#define TIM_DIV_SHIFT				0
+
+#define DAT_OFFSET				0x00000028
+
+#define TOUT_OFFSET				0x0000002c
+
+#define TXFCR_OFFSET				0x0000003c
+#define TXFCR_FIFO_FLUSH_MASK			0x00000080
+#define TXFCR_FIFO_EN_MASK			0x00000040
+
+#define IER_OFFSET				0x00000044
+#define IER_READ_COMPLETE_INT_MASK		0x00000010
+#define IER_I2C_INT_EN_MASK			0x00000008
+#define IER_FIFO_INT_EN_MASK			0x00000002
+#define IER_NOACK_EN_MASK			0x00000001
+
+#define ISR_OFFSET				0x00000048
+#define ISR_RESERVED_MASK			0xffffff60
+#define ISR_CMDBUSY_MASK			0x00000080
+#define ISR_READ_COMPLETE_MASK			0x00000010
+#define ISR_SES_DONE_MASK			0x00000008
+#define ISR_ERR_MASK				0x00000004
+#define ISR_TXFIFOEMPTY_MASK			0x00000002
+#define ISR_NOACK_MASK				0x00000001
+
+#define CLKEN_OFFSET				0x0000004C
+#define CLKEN_AUTOSENSE_OFF_MASK		0x00000080
+#define CLKEN_M_SHIFT				4
+#define CLKEN_N_SHIFT				1
+#define CLKEN_CLKEN_MASK			0x00000001
+
+#define FIFO_STATUS_OFFSET			0x00000054
+#define FIFO_STATUS_RXFIFO_EMPTY_MASK		0x00000004
+#define FIFO_STATUS_TXFIFO_EMPTY_MASK		0x00000010
+
+#define HSTIM_OFFSET				0x00000058
+#define HSTIM_HS_MODE_MASK			0x00008000
+#define HSTIM_HS_HOLD_SHIFT			10
+#define HSTIM_HS_HIGH_PHASE_SHIFT		5
+#define HSTIM_HS_SETUP_SHIFT			0
+
+#define PADCTL_OFFSET				0x0000005c
+#define PADCTL_PAD_OUT_EN_MASK			0x00000004
+
+#define RXFCR_OFFSET				0x00000068
+#define RXFCR_NACK_EN_SHIFT			7
+#define RXFCR_READ_COUNT_SHIFT			0
+#define RXFIFORDOUT_OFFSET			0x0000006c
+
+/* Locally used constants */
+#define MAX_RX_FIFO_SIZE		64U /* bytes */
+#define MAX_TX_FIFO_SIZE		64U /* bytes */
+
+#define STD_EXT_CLK_FREQ		13000000UL
+#define HS_EXT_CLK_FREQ			104000000UL
+
+#define MASTERCODE			0x08 /* Mastercodes are 0000_1xxxb */
+
+#define I2C_TIMEOUT			100 /* msecs */
+
+/* Operations that can be commanded to the controller */
+enum bcm_kona_cmd_t {
+	BCM_CMD_NOACTION = 0,
+	BCM_CMD_START,
+	BCM_CMD_RESTART,
+	BCM_CMD_STOP,
+};
+
+enum bus_speed_index {
+	BCM_SPD_100K = 0,
+	BCM_SPD_400K,
+	BCM_SPD_1MHZ,
+};
+
+enum hs_bus_speed_index {
+	BCM_SPD_3P4MHZ = 0,
+};
+
+/* Internal divider settings for standard mode, fast mode and fast mode plus */
+struct bus_speed_cfg {
+	uint8_t time_m;		/* Number of cycles for setup time */
+	uint8_t time_n;		/* Number of cycles for hold time */
+	uint8_t prescale;	/* Prescale divider */
+	uint8_t time_p;		/* Timing coefficient */
+	uint8_t no_div;		/* Disable clock divider */
+	uint8_t time_div;	/* Post-prescale divider */
+};
+
+/* Internal divider settings for high-speed mode */
+struct hs_bus_speed_cfg {
+	uint8_t hs_hold;	/* Number of clock cycles SCL stays low until
+				   the end of bit period */
+	uint8_t hs_high_phase;	/* Number of clock cycles SCL stays high
+				   before it falls */
+	uint8_t hs_setup;	/* Number of clock cycles SCL stays low
+				   before it rises  */
+	uint8_t prescale;	/* Prescale divider */
+	uint8_t time_p;		/* Timing coefficient */
+	uint8_t no_div;		/* Disable clock divider */
+	uint8_t time_div;	/* Post-prescale divider */
+};
+
+static const struct bus_speed_cfg std_cfg_table[] = {
+	[BCM_SPD_100K] = {0x01, 0x01, 0x03, 0x06, 0x00, 0x02},
+	[BCM_SPD_400K] = {0x05, 0x01, 0x03, 0x05, 0x01, 0x02},
+	[BCM_SPD_1MHZ] = {0x01, 0x01, 0x03, 0x01, 0x01, 0x03},
+};
+
+static const struct hs_bus_speed_cfg hs_cfg_table[] = {
+	[BCM_SPD_3P4MHZ] = {0x01, 0x08, 0x14, 0x00, 0x06, 0x01, 0x00},
+};
+
+struct bcm_kona_i2c_dev {
+	struct device *device;
+
+	void __iomem *base;
+	int irq;
+	struct clk *external_clk;
+
+	struct i2c_adapter adapter;
+
+	struct completion done;
+
+	const struct bus_speed_cfg *std_cfg;
+	const struct hs_bus_speed_cfg *hs_cfg;
+};
+
+static void bcm_kona_i2c_send_cmd_to_ctrl(struct bcm_kona_i2c_dev *dev,
+					  enum bcm_kona_cmd_t cmd)
+{
+	dev_dbg(dev->device, "%s, %d\n", __func__, cmd);
+
+	switch (cmd) {
+	case BCM_CMD_NOACTION:
+		writel((CS_CMD_CMD_NO_ACTION << CS_CMD_SHIFT) |
+		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
+		       dev->base + CS_OFFSET);
+		break;
+
+	case BCM_CMD_START:
+		writel((CS_ACK_CMD_GEN_START << CS_ACK_SHIFT) |
+		       (CS_CMD_CMD_START_RESTART << CS_CMD_SHIFT) |
+		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
+		       dev->base + CS_OFFSET);
+		break;
+
+	case BCM_CMD_RESTART:
+		writel((CS_ACK_CMD_GEN_RESTART << CS_ACK_SHIFT) |
+		       (CS_CMD_CMD_START_RESTART << CS_CMD_SHIFT) |
+		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
+		       dev->base + CS_OFFSET);
+		break;
+
+	case BCM_CMD_STOP:
+		writel((CS_CMD_CMD_STOP << CS_CMD_SHIFT) |
+		       (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
+		       dev->base + CS_OFFSET);
+		break;
+
+	default:
+		dev_err(dev->device, "Unknown command %d\n", cmd);
+	}
+}
+
+static void bcm_kona_i2c_enable_clock(struct bcm_kona_i2c_dev *dev)
+{
+	writel(readl(dev->base + CLKEN_OFFSET) | CLKEN_CLKEN_MASK,
+	       dev->base + CLKEN_OFFSET);
+}
+
+static void bcm_kona_i2c_disable_clock(struct bcm_kona_i2c_dev *dev)
+{
+	writel(readl(dev->base + CLKEN_OFFSET) & ~CLKEN_CLKEN_MASK,
+	       dev->base + CLKEN_OFFSET);
+}
+
+static irqreturn_t bcm_kona_i2c_isr(int irq, void *devid)
+{
+	struct bcm_kona_i2c_dev *dev = devid;
+	uint32_t status = readl(dev->base + ISR_OFFSET);
+
+	if ((status & ~ISR_RESERVED_MASK) == 0)
+		return IRQ_NONE;
+
+	/* Must flush the TX FIFO when NAK detected */
+	if (status & ISR_NOACK_MASK)
+		writel(TXFCR_FIFO_FLUSH_MASK | TXFCR_FIFO_EN_MASK,
+		       dev->base + TXFCR_OFFSET);
+
+	writel(status & ~ISR_RESERVED_MASK, dev->base + ISR_OFFSET);
+	complete_all(&dev->done);
+
+	return IRQ_HANDLED;
+}
+
+/* Wait for ISR_CMDBUSY_MASK to go low before writing to CS, DAT, or RCD */
+static int bcm_kona_i2c_wait_if_busy(struct bcm_kona_i2c_dev *dev)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT);
+
+	while (readl(dev->base + ISR_OFFSET) & ISR_CMDBUSY_MASK)
+		if (time_after(jiffies, timeout)) {
+			dev_err(dev->device, "CMDBUSY timeout\n");
+			return -ETIMEDOUT;
+		}
+
+	return 0;
+}
+
+/* Send command to I2C bus */
+static int bcm_kona_send_i2c_cmd(struct bcm_kona_i2c_dev *dev,
+				 enum bcm_kona_cmd_t cmd)
+{
+	int rc;
+	unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT);
+
+	/* Make sure the hardware is ready */
+	rc = bcm_kona_i2c_wait_if_busy(dev);
+	if (rc < 0)
+		return rc;
+
+	/* Unmask the session done interrupt */
+	writel(IER_I2C_INT_EN_MASK, dev->base + IER_OFFSET);
+
+	/* Mark as incomplete before sending the command */
+	INIT_COMPLETION(dev->done);
+
+	/* Send the command */
+	bcm_kona_i2c_send_cmd_to_ctrl(dev, cmd);
+
+	/* Wait for transaction to finish or timeout */
+	time_left = wait_for_completion_timeout(&dev->done, time_left);
+
+	/* Mask all interrupts */
+	writel(0, dev->base + IER_OFFSET);
+
+	if (!time_left) {
+		dev_err(dev->device, "controller timed out\n");
+		rc = -ETIMEDOUT;
+	}
+
+	/* Clear command */
+	bcm_kona_i2c_send_cmd_to_ctrl(dev, BCM_CMD_NOACTION);
+
+	return rc;
+}
+
+/* Read a single RX FIFO worth of data from the i2c bus */
+static int bcm_kona_i2c_read_fifo_single(struct bcm_kona_i2c_dev *dev,
+					 uint8_t *buf, unsigned int len,
+					 unsigned int last_byte_nak)
+{
+	unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT);
+
+	/* Mark as incomplete before starting the RX FIFO */
+	INIT_COMPLETION(dev->done);
+
+	/* Unmask the read complete interrupt */
+	writel(IER_READ_COMPLETE_INT_MASK, dev->base + IER_OFFSET);
+
+	/* Start the RX FIFO */
+	writel((last_byte_nak << RXFCR_NACK_EN_SHIFT) |
+	       (len << RXFCR_READ_COUNT_SHIFT),
+		dev->base + RXFCR_OFFSET);
+
+	/* Wait for FIFO read to complete */
+	time_left = wait_for_completion_timeout(&dev->done, time_left);
+
+	/* Mask all interrupts */
+	writel(0, dev->base + IER_OFFSET);
+
+	if (!time_left) {
+		dev_err(dev->device, "RX FIFO time out\n");
+		return -EREMOTEIO;
+	}
+
+	/* Read data from FIFO */
+	for (; len > 0; len--, buf++)
+		*buf = readl(dev->base + RXFIFORDOUT_OFFSET);
+
+	return 0;
+}
+
+/* Read any amount of data using the RX FIFO from the i2c bus */
+static int bcm_kona_i2c_read_fifo(struct bcm_kona_i2c_dev *dev,
+				  struct i2c_msg *msg)
+{
+	unsigned int bytes_to_read = MAX_RX_FIFO_SIZE;
+	unsigned int last_byte_nak = 0;
+	unsigned int bytes_read = 0;
+	int rc;
+
+	uint8_t *tmp_buf = msg->buf;
+
+	while (bytes_read < msg->len) {
+		if (msg->len - bytes_read <= MAX_RX_FIFO_SIZE) {
+			last_byte_nak = 1; /* NAK last byte of transfer */
+			bytes_to_read = msg->len - bytes_read;
+		}
+
+		rc = bcm_kona_i2c_read_fifo_single(dev, tmp_buf, bytes_to_read,
+						   last_byte_nak);
+		if (rc < 0)
+			return -EREMOTEIO;
+
+		bytes_read += bytes_to_read;
+		tmp_buf += bytes_to_read;
+	}
+
+	return 0;
+}
+
+/* Write a single byte of data to the i2c bus */
+static int bcm_kona_i2c_write_byte(struct bcm_kona_i2c_dev *dev, uint8_t data,
+				   unsigned int nak_expected)
+{
+	int rc;
+	unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT);
+	unsigned int nak_received;
+
+	/* Make sure the hardware is ready */
+	rc = bcm_kona_i2c_wait_if_busy(dev);
+	if (rc < 0)
+		return rc;
+
+	/* Clear pending session done interrupt */
+	writel(ISR_SES_DONE_MASK, dev->base + ISR_OFFSET);
+
+	/* Unmask the session done interrupt */
+	writel(IER_I2C_INT_EN_MASK, dev->base + IER_OFFSET);
+
+	/* Mark as incomplete before sending the data */
+	INIT_COMPLETION(dev->done);
+
+	/* Send one byte of data */
+	writel(data, dev->base + DAT_OFFSET);
+
+	/* Wait for byte to be written */
+	time_left = wait_for_completion_timeout(&dev->done, time_left);
+
+	/* Mask all interrupts */
+	writel(0, dev->base + IER_OFFSET);
+
+	if (!time_left) {
+		dev_dbg(dev->device, "controller timed out\n");
+		return -ETIMEDOUT;
+	}
+
+	nak_received = readl(dev->base + CS_OFFSET) & CS_ACK_MASK ? 1 : 0;
+
+	if (nak_received ^ nak_expected) {
+		dev_dbg(dev->device, "unexpected NAK/ACK\n");
+		return -EREMOTEIO;
+	}
+
+	return 0;
+}
+
+/* Write a single TX FIFO worth of data to the i2c bus */
+static int bcm_kona_i2c_write_fifo_single(struct bcm_kona_i2c_dev *dev,
+					  uint8_t *buf, unsigned int len)
+{
+	int k;
+	unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT);
+	unsigned int fifo_status;
+
+	/* Mark as incomplete before sending data to the TX FIFO */
+	INIT_COMPLETION(dev->done);
+
+	/* Unmask the fifo empty and nak interrupt */
+	writel(IER_FIFO_INT_EN_MASK | IER_NOACK_EN_MASK,
+	       dev->base + IER_OFFSET);
+
+	/* Disable IRQ to load a FIFO worth of data without interruption */
+	disable_irq(dev->irq);
+
+	/* Write data into FIFO */
+	for (k = 0; k < len; k++)
+		writel(buf[k], (dev->base + DAT_OFFSET));
+
+	/* Enable IRQ now that data has been loaded */
+	enable_irq(dev->irq);
+
+	/* Wait for FIFO to empty */
+	do {
+		time_left = wait_for_completion_timeout(&dev->done, time_left);
+		fifo_status = readl(dev->base + FIFO_STATUS_OFFSET);
+	} while (time_left && !(fifo_status & FIFO_STATUS_TXFIFO_EMPTY_MASK));
+
+	/* Mask all interrupts */
+	writel(0, dev->base + IER_OFFSET);
+
+	/* Check if there was a NAK */
+	if (readl(dev->base + CS_OFFSET) & CS_ACK_MASK) {
+		dev_err(dev->device, "unexpected NAK\n");
+		return -EREMOTEIO;
+	}
+
+	/* Check if a timeout occured */
+	if (!time_left) {
+		dev_err(dev->device, "completion timed out\n");
+		return -EREMOTEIO;
+	}
+
+	return 0;
+}
+
+
+/* Write any amount of data using TX FIFO to the i2c bus */
+static int bcm_kona_i2c_write_fifo(struct bcm_kona_i2c_dev *dev,
+				   struct i2c_msg *msg)
+{
+	unsigned int bytes_to_write = MAX_TX_FIFO_SIZE;
+	unsigned int bytes_written = 0;
+	int rc;
+
+	uint8_t *tmp_buf = msg->buf;
+
+	while (bytes_written < msg->len) {
+		if (msg->len - bytes_written <= MAX_TX_FIFO_SIZE)
+			bytes_to_write = msg->len - bytes_written;
+
+		rc = bcm_kona_i2c_write_fifo_single(dev, tmp_buf,
+						    bytes_to_write);
+		if (rc < 0)
+			return -EREMOTEIO;
+
+		bytes_written += bytes_to_write;
+		tmp_buf += bytes_to_write;
+	}
+
+	return 0;
+}
+
+/* Send i2c address */
+static int bcm_kona_i2c_do_addr(struct bcm_kona_i2c_dev *dev,
+				     struct i2c_msg *msg)
+{
+	unsigned char addr;
+
+	if (msg->flags & I2C_M_TEN) {
+		/* First byte is 11110XX0 where XX is upper 2 bits */
+		addr = 0xF0 | ((msg->addr & 0x300) >> 7);
+		if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
+			return -EREMOTEIO;
+
+		/* Second byte is the remaining 8 bits */
+		addr = msg->addr & 0xFF;
+		if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
+			return -EREMOTEIO;
+
+		if (msg->flags & I2C_M_RD) {
+			/* For read, send restart command */
+			if (bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART) < 0)
+				return -EREMOTEIO;
+
+			/* Then re-send the first byte with the read bit set */
+			addr = 0xF0 | ((msg->addr & 0x300) >> 7) | 0x01;
+			if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
+				return -EREMOTEIO;
+		}
+	} else {
+		addr = msg->addr << 1;
+
+		if (msg->flags & I2C_M_RD)
+			addr |= 1;
+
+		if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
+			return -EREMOTEIO;
+	}
+
+	return 0;
+}
+
+static void bcm_kona_i2c_enable_autosense(struct bcm_kona_i2c_dev *dev)
+{
+	writel(readl(dev->base + CLKEN_OFFSET) & ~CLKEN_AUTOSENSE_OFF_MASK,
+	       dev->base + CLKEN_OFFSET);
+}
+
+static void bcm_kona_i2c_config_timing(struct bcm_kona_i2c_dev *dev)
+{
+	writel(readl(dev->base + HSTIM_OFFSET) & ~HSTIM_HS_MODE_MASK,
+	       dev->base + HSTIM_OFFSET);
+
+	writel((dev->std_cfg->prescale << TIM_PRESCALE_SHIFT) |
+	       (dev->std_cfg->time_p << TIM_P_SHIFT) |
+	       (dev->std_cfg->no_div << TIM_NO_DIV_SHIFT) |
+	       (dev->std_cfg->time_div	<< TIM_DIV_SHIFT),
+	       dev->base + TIM_OFFSET);
+
+	writel((dev->std_cfg->time_m << CLKEN_M_SHIFT) |
+	       (dev->std_cfg->time_n << CLKEN_N_SHIFT) |
+	       CLKEN_CLKEN_MASK,
+	       dev->base + CLKEN_OFFSET);
+}
+
+static void bcm_kona_i2c_config_timing_hs(struct bcm_kona_i2c_dev *dev)
+{
+	writel((dev->hs_cfg->prescale << TIM_PRESCALE_SHIFT) |
+	       (dev->hs_cfg->time_p << TIM_P_SHIFT) |
+	       (dev->hs_cfg->no_div << TIM_NO_DIV_SHIFT) |
+	       (dev->hs_cfg->time_div << TIM_DIV_SHIFT),
+	       dev->base + TIM_OFFSET);
+
+	writel((dev->hs_cfg->hs_hold << HSTIM_HS_HOLD_SHIFT) |
+	       (dev->hs_cfg->hs_high_phase << HSTIM_HS_HIGH_PHASE_SHIFT) |
+	       (dev->hs_cfg->hs_setup << HSTIM_HS_SETUP_SHIFT),
+	       dev->base + HSTIM_OFFSET);
+
+	writel(readl(dev->base + HSTIM_OFFSET) | HSTIM_HS_MODE_MASK,
+	       dev->base + HSTIM_OFFSET);
+}
+
+static int bcm_kona_i2c_switch_to_hs(struct bcm_kona_i2c_dev *dev)
+{
+	int rc;
+
+	/* Send mastercode at standard speed */
+	rc = bcm_kona_i2c_write_byte(dev, MASTERCODE, 1);
+	if (rc < 0) {
+		pr_err("High speed handshake failed\n");
+		return rc;
+	}
+
+	/* Configure external clock to higher frequency */
+	rc = clk_set_rate(dev->external_clk, HS_EXT_CLK_FREQ);
+	if (rc) {
+		dev_err(dev->device, "%s: clk_set_rate returned %d\n",
+			__func__, rc);
+		return rc;
+	}
+
+	/* Reconfigure internal dividers */
+	bcm_kona_i2c_config_timing_hs(dev);
+
+	/* Send a restart command */
+	rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART);
+	if (rc < 0)
+		dev_err(dev->device, "High speed restart command failed\n");
+
+	return rc;
+}
+
+static int bcm_kona_i2c_switch_to_std(struct bcm_kona_i2c_dev *dev)
+{
+	int rc;
+
+	/* Reconfigure internal dividers */
+	bcm_kona_i2c_config_timing(dev);
+
+	/* Configure external clock to lower frequency */
+	rc = clk_set_rate(dev->external_clk, STD_EXT_CLK_FREQ);
+	if (rc) {
+		dev_err(dev->device, "%s: clk_set_rate returned %d\n",
+			__func__, rc);
+	}
+
+	return rc;
+}
+
+/* Master transfer function */
+static int bcm_kona_i2c_xfer(struct i2c_adapter *adapter,
+			     struct i2c_msg msgs[], int num)
+{
+	struct bcm_kona_i2c_dev *dev = i2c_get_adapdata(adapter);
+	struct i2c_msg *pmsg;
+	int rc = 0;
+	int i;
+
+	rc = clk_prepare_enable(dev->external_clk);
+	if (rc) {
+		dev_err(dev->device, "%s: peri clock enable failed. err %d\n",
+			__func__, rc);
+		return rc;
+	}
+
+	/* Enable pad output */
+	writel(0, dev->base + PADCTL_OFFSET);
+
+	/* Enable internal clocks */
+	bcm_kona_i2c_enable_clock(dev);
+
+	/* Send start command */
+	rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_START);
+	if (rc < 0) {
+		dev_err(dev->device, "Start command failed rc = %d\n", rc);
+		goto xfer_disable_pad;
+	}
+
+	/* Switch to high speed if applicable */
+	if (dev->hs_cfg) {
+		rc = bcm_kona_i2c_switch_to_hs(dev);
+		if (rc < 0)
+			goto xfer_send_stop;
+	}
+
+	/* Loop through all messages */
+	for (i = 0; i < num; i++) {
+		pmsg = &msgs[i];
+
+		/* Send restart for subsequent messages */
+		if ((i != 0) && ((pmsg->flags & I2C_M_NOSTART) == 0)) {
+			rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART);
+			if (rc < 0) {
+				dev_err(dev->device,
+					"restart cmd failed rc = %d\n", rc);
+					goto xfer_send_stop;
+			}
+		}
+
+		/* Send slave address */
+		if (!(pmsg->flags & I2C_M_NOSTART)) {
+			rc = bcm_kona_i2c_do_addr(dev, pmsg);
+			if (rc < 0) {
+				dev_err(dev->device,
+					"NAK from addr %2.2x msg#%d rc = %d\n",
+					pmsg->addr, i, rc);
+				goto xfer_send_stop;
+			}
+		}
+
+		/* Perform data transfer */
+		if (pmsg->flags & I2C_M_RD) {
+			rc = bcm_kona_i2c_read_fifo(dev, pmsg);
+			if (rc < 0) {
+				dev_err(dev->device, "read failure\n");
+				goto xfer_send_stop;
+			}
+		} else {
+			rc = bcm_kona_i2c_write_fifo(dev, pmsg);
+			if (rc < 0) {
+				dev_err(dev->device, "write failure");
+				goto xfer_send_stop;
+			}
+		}
+	}
+
+	rc = num;
+
+xfer_send_stop:
+	/* Send a STOP command */
+	bcm_kona_send_i2c_cmd(dev, BCM_CMD_STOP);
+
+	/* Return from high speed if applicable */
+	if (dev->hs_cfg) {
+		int hs_rc = bcm_kona_i2c_switch_to_std(dev);
+
+		if (hs_rc)
+			rc = hs_rc;
+	}
+
+xfer_disable_pad:
+	/* Disable pad output */
+	writel(PADCTL_PAD_OUT_EN_MASK, dev->base + PADCTL_OFFSET);
+
+	/* Stop internal clock */
+	bcm_kona_i2c_disable_clock(dev);
+
+	clk_disable_unprepare(dev->external_clk);
+
+	return rc;
+}
+
+static uint32_t bcm_kona_i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
+	    I2C_FUNC_NOSTART;
+}
+
+static const struct i2c_algorithm bcm_algo = {
+	.master_xfer = bcm_kona_i2c_xfer,
+	.functionality = bcm_kona_i2c_functionality,
+};
+
+static int bcm_kona_i2c_assign_bus_speed(struct bcm_kona_i2c_dev *dev)
+{
+	unsigned int bus_speed;
+	int ret = of_property_read_u32(dev->device->of_node, "clock-frequency",
+				       &bus_speed);
+	if (ret < 0) {
+		dev_err(dev->device, "missing clock-frequency property\n");
+		return -ENODEV;
+	}
+
+	switch (bus_speed) {
+	case 100000:
+		dev->std_cfg = &std_cfg_table[BCM_SPD_100K];
+		break;
+	case 400000:
+		dev->std_cfg = &std_cfg_table[BCM_SPD_400K];
+		break;
+	case 1000000:
+		dev->std_cfg = &std_cfg_table[BCM_SPD_1MHZ];
+		break;
+	case 3400000:
+		/* Send mastercode at 100k */
+		dev->std_cfg = &std_cfg_table[BCM_SPD_100K];
+		dev->hs_cfg = &hs_cfg_table[BCM_SPD_3P4MHZ];
+		break;
+	default:
+		pr_err("%d hz bus speed not supported\n", bus_speed);
+		pr_err("Valid speeds are 100khz, 400khz, 1mhz, and 3.4mhz\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int bcm_kona_i2c_probe(struct platform_device *pdev)
+{
+	int rc = 0;
+	struct bcm_kona_i2c_dev *dev;
+	struct i2c_adapter *adap;
+	struct resource *iomem;
+
+	/* Allocate memory for private data structure */
+	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, dev);
+	dev->device = &pdev->dev;
+	init_completion(&dev->done);
+
+	/* Map hardware registers */
+	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dev->base = devm_ioremap_resource(dev->device, iomem);
+	if (IS_ERR(dev->base))
+		return -ENOMEM;
+
+	/* Get and enable external clock */
+	dev->external_clk = devm_clk_get(dev->device, NULL);
+	if (IS_ERR(dev->external_clk)) {
+		dev_err(dev->device, "couldn't get clock\n");
+		return -ENODEV;
+	}
+
+	rc = clk_set_rate(dev->external_clk, STD_EXT_CLK_FREQ);
+	if (rc) {
+		dev_err(dev->device, "%s: clk_set_rate returned %d\n",
+			__func__, rc);
+		return rc;
+	}
+
+	rc = clk_prepare_enable(dev->external_clk);
+	if (rc) {
+		dev_err(dev->device, "couldn't enable clock\n");
+		return rc;
+	}
+
+	/* Parse bus speed */
+	if (bcm_kona_i2c_assign_bus_speed(dev))
+		goto probe_disable_clk;
+
+	/* Enable internal clocks */
+	bcm_kona_i2c_enable_clock(dev);
+
+	/* Configure internal dividers */
+	bcm_kona_i2c_config_timing(dev);
+
+	/* Disable timeout */
+	writel(0, dev->base + TOUT_OFFSET);
+
+	/* Enable autosense */
+	bcm_kona_i2c_enable_autosense(dev);
+
+	/* Enable TX FIFO */
+	writel(TXFCR_FIFO_FLUSH_MASK | TXFCR_FIFO_EN_MASK,
+	       dev->base + TXFCR_OFFSET);
+
+	/* Mask all interrupts */
+	writel(0, dev->base + IER_OFFSET);
+
+	/* Clear all pending interrupts */
+	writel(ISR_CMDBUSY_MASK |
+	       ISR_READ_COMPLETE_MASK |
+	       ISR_SES_DONE_MASK |
+	       ISR_ERR_MASK |
+	       ISR_TXFIFOEMPTY_MASK |
+	       ISR_NOACK_MASK,
+	       dev->base + ISR_OFFSET);
+
+	/* Get the interrupt number */
+	dev->irq = platform_get_irq(pdev, 0);
+	if (dev->irq < 0) {
+		dev_err(dev->device, "no irq resource\n");
+		rc = -ENODEV;
+		goto probe_disable_clk;
+	}
+
+	/* register the ISR handler */
+	rc = devm_request_irq(&pdev->dev, dev->irq, bcm_kona_i2c_isr,
+			      IRQF_SHARED, pdev->name, dev);
+	if (rc) {
+		dev_err(dev->device, "failed to request irq %i\n", dev->irq);
+		goto probe_disable_clk;
+	}
+
+	/* Enable the controller but leave it idle */
+	bcm_kona_i2c_send_cmd_to_ctrl(dev, BCM_CMD_NOACTION);
+
+	/* Disable pad output */
+	writel(PADCTL_PAD_OUT_EN_MASK, dev->base + PADCTL_OFFSET);
+
+	/* Disable internal clock */
+	bcm_kona_i2c_disable_clock(dev);
+
+	/* Disable external clock */
+	clk_disable_unprepare(dev->external_clk);
+
+	/* Add the i2c adapter */
+	adap = &dev->adapter;
+	i2c_set_adapdata(adap, dev);
+	adap->owner = THIS_MODULE;
+	strlcpy(adap->name, "Broadcom I2C adapter", sizeof(adap->name));
+	adap->algo = &bcm_algo;
+	adap->dev.parent = &pdev->dev;
+	adap->dev.of_node = pdev->dev.of_node;
+
+	rc = i2c_add_adapter(adap);
+	if (rc) {
+		dev_err(dev->device, "failed to add adapter\n");
+		return rc;
+	}
+
+	dev_info(dev->device, "device registered successfully\n");
+
+	return 0;
+
+probe_disable_clk:
+	bcm_kona_i2c_disable_clock(dev);
+	clk_disable_unprepare(dev->external_clk);
+
+	return rc;
+}
+
+static int bcm_kona_i2c_remove(struct platform_device *pdev)
+{
+	struct bcm_kona_i2c_dev *dev = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&dev->adapter);
+
+	return 0;
+}
+
+static const struct of_device_id bcm_kona_i2c_of_match[] = {
+	{.compatible = "brcm,kona-i2c",},
+	{},
+};
+MODULE_DEVICE_TABLE(of, kona_i2c_of_match);
+
+static struct platform_driver bcm_kona_i2c_driver = {
+	.driver = {
+		   .name = "bcm-kona-i2c",
+		   .owner = THIS_MODULE,
+		   .of_match_table = bcm_kona_i2c_of_match,
+		   },
+	.probe = bcm_kona_i2c_probe,
+	.remove = bcm_kona_i2c_remove,
+};
+module_platform_driver(bcm_kona_i2c_driver);
+
+MODULE_AUTHOR("Tim Kryger <tkryger@broadcom.com>");
+MODULE_DESCRIPTION("Broadcom Kona I2C Driver");
+MODULE_LICENSE("GPL v2");