diff mbox

[V4,1/2] i2c: brcmstb: Add Broadcom settop SoC i2c controller driver

Message ID 1432052625-6210-1-git-send-email-kdasu.kdev@gmail.com
State Superseded
Delegated to: Wolfram Sang
Headers show

Commit Message

Kamal Dasu May 19, 2015, 4:23 p.m. UTC
Adding support for i2c controller driver for Broadcom settop
SoCs.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
---
 - added COMPILE_TEST dependency to CONFIG_I2C_BRCMSTB
 - alphabetically ordered delay.h before device.h
 - disabled l2 interrupt on a timeout 
 - removed redundant white spaces 
 - call brcmstb_i2c_set_bsc_reg_defaults()
   before calling i2c_add_adapter()
 - removed kfree(dev->bsc_regmap) since using devm_kzalloc()
   for bsc_regmap
---
 drivers/i2c/busses/Kconfig       |  10 +
 drivers/i2c/busses/Makefile      |   1 +
 drivers/i2c/busses/i2c-brcmstb.c | 697 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 708 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-brcmstb.c

Comments

Ray Jui May 19, 2015, 8:50 p.m. UTC | #1
Hi Kamal,

There's one change still missing (that I mentioned when reviewing v2 of 
the patchset):

 >>>
What is the max len that can be supported? BSC_CNT_REG1_MASK = 63? Then
you should check against that.

Note Wolfram has introduced a way to validate the supported data length
at the i2c-core, which you should adapt:

commit b7f625840267b18ef1011cba0085bb7e237d76f7
Author: Wolfram Sang <wsa@the-dreams.de>
Date:   Mon Jan 5 23:45:59 2015 +0100

     i2c: add quirk checks to core

     Let the core do the checks if HW quirks prevent a transfer. Saves code
     from drivers and adds consistency.
<<<

So you should add struct i2c_adapter_quirks and set the max_read_len and 
max_write_len.

I have no more comment for the rest of the code.

Thanks,

Ray

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Kamal Dasu May 20, 2015, 8:35 p.m. UTC | #2
Ray,

I am using  non combined operation so it not necessary have limit. I
am not sending a stop condition till the last byte is written or read.
So if the xfer has more than the i2c buffer len we break up the
transfers after the initial salve address write into max read/write
data buffer size.

Thanks
Kamal

On Tue, May 19, 2015 at 4:50 PM, Ray Jui <rjui@broadcom.com> wrote:
> Hi Kamal,
>
> There's one change still missing (that I mentioned when reviewing v2 of the
> patchset):
>
>>>>
> What is the max len that can be supported? BSC_CNT_REG1_MASK = 63? Then
> you should check against that.
>
> Note Wolfram has introduced a way to validate the supported data length
> at the i2c-core, which you should adapt:
>
> commit b7f625840267b18ef1011cba0085bb7e237d76f7
> Author: Wolfram Sang <wsa@the-dreams.de>
> Date:   Mon Jan 5 23:45:59 2015 +0100
>
>     i2c: add quirk checks to core
>
>     Let the core do the checks if HW quirks prevent a transfer. Saves code
>     from drivers and adds consistency.
> <<<
>
> So you should add struct i2c_adapter_quirks and set the max_read_len and
> max_write_len.
>
> I have no more comment for the rest of the code.
>
> Thanks,
>
> Ray
>
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Ray Jui May 20, 2015, 8:37 p.m. UTC | #3
Okay, Kamal. I got it. Thanks for the explanation.

Wolfram, I have no more comment on this patch.

Thanks,

Ray

On 5/20/2015 1:35 PM, Kamal Dasu wrote:
> Ray,
> 
> I am using  non combined operation so it not necessary have limit. I
> am not sending a stop condition till the last byte is written or read.
> So if the xfer has more than the i2c buffer len we break up the
> transfers after the initial salve address write into max read/write
> data buffer size.
> 
> Thanks
> Kamal
> 
> On Tue, May 19, 2015 at 4:50 PM, Ray Jui <rjui@broadcom.com> wrote:
>> Hi Kamal,
>>
>> There's one change still missing (that I mentioned when reviewing v2 of the
>> patchset):
>>
>>>>>
>> What is the max len that can be supported? BSC_CNT_REG1_MASK = 63? Then
>> you should check against that.
>>
>> Note Wolfram has introduced a way to validate the supported data length
>> at the i2c-core, which you should adapt:
>>
>> commit b7f625840267b18ef1011cba0085bb7e237d76f7
>> Author: Wolfram Sang <wsa@the-dreams.de>
>> Date:   Mon Jan 5 23:45:59 2015 +0100
>>
>>     i2c: add quirk checks to core
>>
>>     Let the core do the checks if HW quirks prevent a transfer. Saves code
>>     from drivers and adds consistency.
>> <<<
>>
>> So you should add struct i2c_adapter_quirks and set the max_read_len and
>> max_write_len.
>>
>> I have no more comment for the rest of the code.
>>
>> Thanks,
>>
>> Ray
>>
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Wolfram Sang June 3, 2015, 3:54 p.m. UTC | #4
On Tue, May 19, 2015 at 12:23:44PM -0400, Kamal Dasu wrote:
> Adding support for i2c controller driver for Broadcom settop
> SoCs.
> 
> Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>

We are very close.

> +/* Wait for device to be ready */
> +static int brcmstb_i2c_wait_if_busy(struct brcmstb_i2c_dev *dev)
> +{
> +	unsigned long timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT);
> +
> +	while ((bsc_readl(dev, iic_enable) & BSC_IIC_EN_INTRP_MASK)) {
> +		if (time_after(jiffies, timeout)) {
> +			dev_err(dev->device, "i2c device busy timeout\n");

Don't print out, it will spoil the logs. Timeouts can happen on I2C
busses, no need to inform the user.

...

> +	/* Wait for transaction to finish or timeout */
> +	rc = brcmstb_i2c_wait_for_completion(dev);
> +	if (rc) {
> +		dev_err(dev->device, "intr timeout for cmd %s\n",
> +			cmd_string[cmd]);
> +		goto cmd_out;
> +	}

ditto

> +
> +	if ((CMD_RD || CMD_WR) &&
> +	    bsc_readl(dev, iic_enable) & BSC_IIC_EN_NOACK_MASK) {
> +		rc = -EREMOTEIO;
> +		dev_dbg(dev->device, "controller received NOACK intr for %s\n",
> +			cmd_string[cmd]);

I'd leave this out, too. But you decide.

...

> +	rc = of_property_read_string(dev->device->of_node, "interrupt-names",
> +				     &int_name);

I haven't checked but is that really needed? of_irq_to_resource() seems
to parse the "interrupt-names" property.

Thanks,

   Wolfram
diff mbox

Patch

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 2255af2..c35903a 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -392,6 +392,16 @@  config I2C_BCM_KONA
 
 	  If you do not need KONA I2C interface, say N.
 
+config I2C_BRCMSTB
+	tristate "BRCM Settop I2C controller"
+	depends on ARCH_BRCMSTB || COMPILE_TEST
+	default y
+	help
+	  If you say yes to this option, support will be included for the
+	  I2C interface on the Broadcom Settop SoCs.
+
+	  If you do not need I2C interface, say N.
+
 config I2C_BLACKFIN_TWI
 	tristate "Blackfin TWI I2C support"
 	depends on BLACKFIN
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index cdf941d..aedea68 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -105,6 +105,7 @@  obj-$(CONFIG_I2C_VIPERBOARD)	+= i2c-viperboard.o
 # Other I2C/SMBus bus drivers
 obj-$(CONFIG_I2C_ACORN)		+= i2c-acorn.o
 obj-$(CONFIG_I2C_BCM_KONA)	+= i2c-bcm-kona.o
+obj-$(CONFIG_I2C_BRCMSTB)	+= i2c-brcmstb.o
 obj-$(CONFIG_I2C_CROS_EC_TUNNEL)	+= i2c-cros-ec-tunnel.o
 obj-$(CONFIG_I2C_ELEKTOR)	+= i2c-elektor.o
 obj-$(CONFIG_I2C_OPAL)		+= i2c-opal.o
diff --git a/drivers/i2c/busses/i2c-brcmstb.c b/drivers/i2c/busses/i2c-brcmstb.c
new file mode 100644
index 0000000..086a38a
--- /dev/null
+++ b/drivers/i2c/busses/i2c-brcmstb.c
@@ -0,0 +1,697 @@ 
+/*
+ * Copyright (C) 2014 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/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/version.h>
+
+#define N_DATA_REGS					8
+#define N_DATA_BYTES					(N_DATA_REGS * 4)
+
+/* BSC count register field definitions */
+#define BSC_CNT_REG1_MASK				0x0000003f
+#define BSC_CNT_REG1_SHIFT				0
+#define BSC_CNT_REG2_MASK				0x00000fc0
+#define BSC_CNT_REG2_SHIFT				6
+
+/* BSC CTL register field definitions */
+#define BSC_CTL_REG_DTF_MASK				0x00000003
+#define BSC_CTL_REG_SCL_SEL_MASK			0x00000030
+#define BSC_CTL_REG_SCL_SEL_SHIFT			4
+#define BSC_CTL_REG_INT_EN_MASK				0x00000040
+#define BSC_CTL_REG_INT_EN_SHIFT			6
+#define BSC_CTL_REG_DIV_CLK_MASK			0x00000080
+
+/* BSC_IIC_ENABLE r/w enable and interrupt field defintions */
+#define BSC_IIC_EN_RESTART_MASK				0x00000040
+#define BSC_IIC_EN_NOSTART_MASK				0x00000020
+#define BSC_IIC_EN_NOSTOP_MASK				0x00000010
+#define BSC_IIC_EN_NOACK_MASK				0x00000004
+#define BSC_IIC_EN_INTRP_MASK				0x00000002
+#define BSC_IIC_EN_ENABLE_MASK				0x00000001
+
+/* BSC_CTLHI control register field definitions */
+#define BSC_CTLHI_REG_INPUT_SWITCHING_LEVEL_MASK	0x00000080
+#define BSC_CTLHI_REG_DATAREG_SIZE_MASK			0x00000040
+#define BSC_CTLHI_REG_IGNORE_ACK_MASK			0x00000002
+#define BSC_CTLHI_REG_WAIT_DIS_MASK			0x00000001
+
+#define I2C_TIMEOUT					100 /* msecs */
+
+/* Condition mask used for non combined transfer */
+#define COND_RESTART		BSC_IIC_EN_RESTART_MASK
+#define COND_NOSTART		BSC_IIC_EN_NOSTART_MASK
+#define COND_NOSTOP		BSC_IIC_EN_NOSTOP_MASK
+#define COND_START_STOP		(COND_RESTART | COND_NOSTART | COND_NOSTOP)
+
+/* BSC data transfer direction */
+#define DTF_WR_MASK		0x00000000
+#define DTF_RD_MASK		0x00000001
+/* BSC data transfer direction combined format */
+#define DTF_RD_WR_MASK		0x00000002
+#define DTF_WR_RD_MASK		0x00000003
+
+#define INT_ENABLE		true
+#define INT_DISABLE		false
+
+/* BSC block register map structure to cache fields to be written */
+struct bsc_regs {
+	u32	chip_address;           /* slave address */
+	u32	data_in[N_DATA_REGS];   /* tx data buffer*/
+	u32	cnt_reg;		/* rx/tx data length */
+	u32	ctl_reg;		/* control register */
+	u32	iic_enable;		/* xfer enable and status */
+	u32	data_out[N_DATA_REGS];  /* rx data buffer */
+	u32	ctlhi_reg;		/* more control fields */
+	u32	scl_param;		/* reserved */
+};
+
+struct bsc_clk_param {
+	u32 hz;
+	u32 scl_mask;
+	u32 div_mask;
+};
+
+enum bsc_xfer_cmd {
+	CMD_WR,
+	CMD_RD,
+	CMD_WR_NOACK,
+	CMD_RD_NOACK,
+};
+
+static char const *cmd_string[] = {
+	[CMD_WR] = "WR",
+	[CMD_RD] = "RD",
+	[CMD_WR_NOACK] = "WR NOACK",
+	[CMD_RD_NOACK] = "RD NOACK",
+};
+
+enum bus_speeds {
+	SPD_375K,
+	SPD_390K,
+	SPD_187K,
+	SPD_200K,
+	SPD_93K,
+	SPD_97K,
+	SPD_46K,
+	SPD_50K
+};
+
+static const struct bsc_clk_param bsc_clk[] = {
+	[SPD_375K] = {
+		.hz = 375000,
+		.scl_mask = SPD_375K << BSC_CTL_REG_SCL_SEL_SHIFT,
+		.div_mask = 0
+	},
+	[SPD_390K] = {
+		.hz = 390000,
+		.scl_mask = SPD_390K << BSC_CTL_REG_SCL_SEL_SHIFT,
+		.div_mask = 0
+	},
+	[SPD_187K] = {
+		.hz = 187500,
+		.scl_mask = SPD_187K << BSC_CTL_REG_SCL_SEL_SHIFT,
+		.div_mask = 0
+	},
+	[SPD_200K] = {
+		.hz = 200000,
+		.scl_mask = SPD_200K << BSC_CTL_REG_SCL_SEL_SHIFT,
+		.div_mask = 0
+	},
+	[SPD_93K]  = {
+		.hz = 93750,
+		.scl_mask = SPD_375K << BSC_CTL_REG_SCL_SEL_SHIFT,
+		.div_mask = BSC_CTL_REG_DIV_CLK_MASK
+	},
+	[SPD_97K]  = {
+		.hz = 97500,
+		.scl_mask = SPD_390K << BSC_CTL_REG_SCL_SEL_SHIFT,
+		.div_mask = BSC_CTL_REG_DIV_CLK_MASK
+	},
+	[SPD_46K]  = {
+		.hz = 46875,
+		.scl_mask = SPD_187K << BSC_CTL_REG_SCL_SEL_SHIFT,
+		.div_mask = BSC_CTL_REG_DIV_CLK_MASK
+	},
+	[SPD_50K]  = {
+		.hz = 50000,
+		.scl_mask = SPD_200K << BSC_CTL_REG_SCL_SEL_SHIFT,
+		.div_mask = BSC_CTL_REG_DIV_CLK_MASK
+	}
+};
+
+struct brcmstb_i2c_dev {
+	struct device *device;
+	void __iomem *base;
+	void __iomem *irq_base;
+	int irq;
+	struct bsc_regs *bsc_regmap;
+	struct i2c_adapter adapter;
+	struct completion done;
+	bool is_suspended;
+	u32 clk_freq_hz;
+};
+
+/* register accessors for both be and le cpu arch */
+#ifdef CONFIG_CPU_BIG_ENDIAN
+#define __bsc_readl(_reg) ioread32be(_reg)
+#define __bsc_writel(_val, _reg) iowrite32be(_val, _reg)
+#else
+#define __bsc_readl(_reg) ioread32(_reg)
+#define __bsc_writel(_val, _reg) iowrite32(_val, _reg)
+#endif
+
+#define bsc_readl(_dev, _reg)						\
+	__bsc_readl(_dev->base + offsetof(struct bsc_regs, _reg))
+
+#define bsc_writel(_dev, _val, _reg)					\
+	__bsc_writel(_val, _dev->base + offsetof(struct bsc_regs, _reg))
+
+static void brcmstb_i2c_enable_disable_irq(struct brcmstb_i2c_dev *dev,
+					   bool int_en)
+{
+
+	if (int_en)
+		/* Enable BSC  CTL interrupt line */
+		dev->bsc_regmap->ctl_reg |= BSC_CTL_REG_INT_EN_MASK;
+	else
+		/* Disable BSC CTL interrupt line */
+		dev->bsc_regmap->ctl_reg &= ~BSC_CTL_REG_INT_EN_MASK;
+
+	barrier();
+	bsc_writel(dev, dev->bsc_regmap->ctl_reg, ctl_reg);
+}
+
+static irqreturn_t brcmstb_i2c_isr(int irq, void *devid)
+{
+	struct brcmstb_i2c_dev *dev = devid;
+	u32 status_bsc_ctl = bsc_readl(dev, ctl_reg);
+	u32 status_iic_intrp = bsc_readl(dev, iic_enable);
+
+	dev_dbg(dev->device, "isr CTL_REG %x IIC_EN %x\n",
+		status_bsc_ctl, status_iic_intrp);
+
+	if (!(status_bsc_ctl & BSC_CTL_REG_INT_EN_MASK))
+		return IRQ_NONE;
+
+	brcmstb_i2c_enable_disable_irq(dev, INT_DISABLE);
+	complete_all(&dev->done);
+
+	dev_dbg(dev->device, "isr handled");
+	return IRQ_HANDLED;
+}
+
+/* Wait for device to be ready */
+static int brcmstb_i2c_wait_if_busy(struct brcmstb_i2c_dev *dev)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT);
+
+	while ((bsc_readl(dev, iic_enable) & BSC_IIC_EN_INTRP_MASK)) {
+		if (time_after(jiffies, timeout)) {
+			dev_err(dev->device, "i2c device busy timeout\n");
+			return -ETIMEDOUT;
+		}
+		cpu_relax();
+	}
+	return 0;
+}
+
+/* i2c xfer completion function, handles both irq and polling mode */
+static int brcmstb_i2c_wait_for_completion(struct brcmstb_i2c_dev *dev)
+{
+	int ret = 0;
+	unsigned long timeout = msecs_to_jiffies(I2C_TIMEOUT);
+
+	if (dev->irq >= 0) {
+		if (!wait_for_completion_timeout(&dev->done, timeout))
+			ret = -ETIMEDOUT;
+	} else {
+		/* we are in polling mode */
+		u32 bsc_intrp;
+		unsigned long time_left = jiffies + timeout;
+
+		do {
+			bsc_intrp = bsc_readl(dev, iic_enable) &
+				BSC_IIC_EN_INTRP_MASK;
+			if (time_after(jiffies, time_left)) {
+				ret = -ETIMEDOUT;
+				break;
+			}
+			cpu_relax();
+		} while (!bsc_intrp);
+	}
+
+	if (dev->irq < 0 || ret == -ETIMEDOUT)
+		brcmstb_i2c_enable_disable_irq(dev, INT_DISABLE);
+
+	return ret;
+}
+
+/* Set xfer START/STOP conditions for subsequent transfer */
+static void brcmstb_set_i2c_start_stop(struct brcmstb_i2c_dev *dev,
+				       u32 cond_flag)
+{
+	u32 regval = dev->bsc_regmap->iic_enable;
+
+	dev->bsc_regmap->iic_enable = (regval & ~COND_START_STOP) | cond_flag;
+}
+
+/* Send I2C request check completion */
+static int brcmstb_send_i2c_cmd(struct brcmstb_i2c_dev *dev,
+				enum bsc_xfer_cmd cmd)
+{
+	int rc = 0;
+	struct bsc_regs *pi2creg = dev->bsc_regmap;
+
+	/* Make sure the hardware is ready */
+	rc = brcmstb_i2c_wait_if_busy(dev);
+	if (rc < 0)
+		return rc;
+
+	/* only if we are in interrupt mode */
+	if (dev->irq >= 0)
+		reinit_completion(&dev->done);
+
+	/* enable BSC CTL interrupt line */
+	brcmstb_i2c_enable_disable_irq(dev, INT_ENABLE);
+
+	/* initiate transfer by setting iic_enable */
+	pi2creg->iic_enable |= BSC_IIC_EN_ENABLE_MASK;
+	bsc_writel(dev, pi2creg->iic_enable, iic_enable);
+
+	/* Wait for transaction to finish or timeout */
+	rc = brcmstb_i2c_wait_for_completion(dev);
+	if (rc) {
+		dev_err(dev->device, "intr timeout for cmd %s\n",
+			cmd_string[cmd]);
+		goto cmd_out;
+	}
+
+	if ((CMD_RD || CMD_WR) &&
+	    bsc_readl(dev, iic_enable) & BSC_IIC_EN_NOACK_MASK) {
+		rc = -EREMOTEIO;
+		dev_dbg(dev->device, "controller received NOACK intr for %s\n",
+			cmd_string[cmd]);
+	}
+
+cmd_out:
+	bsc_writel(dev, 0, cnt_reg);
+	bsc_writel(dev, 0, iic_enable);
+
+	return rc;
+}
+
+/* Actual data transfer through the BSC master */
+static int brcmstb_i2c_xfer_bsc_data(struct brcmstb_i2c_dev *dev,
+				     u8 *buf, unsigned int len,
+				     struct i2c_msg *pmsg)
+{
+	int cnt, byte, rc;
+	enum bsc_xfer_cmd cmd;
+	u32 ctl_reg;
+	struct bsc_regs *pi2creg = dev->bsc_regmap;
+	int no_ack = pmsg->flags & I2C_M_IGNORE_NAK;
+
+	/* see if the transaction needs to check NACK conditions */
+	if (no_ack || len <= N_DATA_BYTES) {
+		cmd = (pmsg->flags & I2C_M_RD) ? CMD_RD_NOACK
+			: CMD_WR_NOACK;
+		pi2creg->ctlhi_reg |= BSC_CTLHI_REG_IGNORE_ACK_MASK;
+	} else {
+		cmd = (pmsg->flags & I2C_M_RD) ? CMD_RD : CMD_WR;
+		pi2creg->ctlhi_reg &= ~BSC_CTLHI_REG_IGNORE_ACK_MASK;
+	}
+	bsc_writel(dev, pi2creg->ctlhi_reg, ctlhi_reg);
+
+	/* set data transfer direction */
+	ctl_reg = pi2creg->ctl_reg & ~BSC_CTL_REG_DTF_MASK;
+	if (cmd == CMD_WR || cmd == CMD_WR_NOACK)
+		pi2creg->ctl_reg = ctl_reg | DTF_WR_MASK;
+	else
+		pi2creg->ctl_reg = ctl_reg | DTF_RD_MASK;
+
+	/* set the read/write length */
+	bsc_writel(dev, BSC_CNT_REG1_MASK & (len << BSC_CNT_REG1_SHIFT),
+		   cnt_reg);
+
+	/* Write data into data_in register */
+	if (cmd == CMD_WR || cmd == CMD_WR_NOACK) {
+		for (cnt = 0; cnt < len; cnt += 4) {
+			u32 word = 0;
+
+			for (byte = 0; byte < 4; byte++) {
+				word >>= 8;
+				if ((cnt + byte) < len)
+					word |= buf[cnt + byte] << 24;
+			}
+			bsc_writel(dev, word, data_in[cnt >> 2]);
+		}
+	}
+
+	/* Initiate xfer, the function will return on completion */
+	rc = brcmstb_send_i2c_cmd(dev, cmd);
+
+	if (rc != 0) {
+		dev_dbg(dev->device, "%s failure", cmd_string[cmd]);
+		return rc;
+	}
+
+	if (cmd == CMD_RD || cmd == CMD_RD_NOACK) {
+		for (cnt = 0; cnt < len; cnt += 4) {
+			u32 data = bsc_readl(dev, data_out[cnt >> 2]);
+
+			for (byte = 0; byte < 4 &&
+				     (byte + cnt) < len; byte++) {
+				buf[cnt + byte] = data & 0xff;
+				data >>= 8;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/* Write a single byte of data to the i2c bus */
+static int brcmstb_i2c_write_data_byte(struct brcmstb_i2c_dev *dev,
+				       u8 *buf, unsigned int nak_expected)
+{
+	enum bsc_xfer_cmd cmd = nak_expected ? CMD_WR : CMD_WR_NOACK;
+
+	bsc_writel(dev, 1, cnt_reg);
+	bsc_writel(dev, *buf, data_in);
+
+	return brcmstb_send_i2c_cmd(dev, cmd);
+}
+
+/* Send i2c address */
+static int brcmstb_i2c_do_addr(struct brcmstb_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);
+		bsc_writel(dev, addr, chip_address);
+
+		/* Second byte is the remaining 8 bits */
+		addr = msg->addr & 0xFF;
+		if (brcmstb_i2c_write_data_byte(dev, &addr, 0) < 0)
+			return -EREMOTEIO;
+
+		if (msg->flags & I2C_M_RD) {
+			/* For read, send restart without stop condition */
+			brcmstb_set_i2c_start_stop(dev, COND_RESTART
+						   | COND_NOSTOP);
+			/* Then re-send the first byte with the read bit set */
+			addr = 0xF0 | ((msg->addr & 0x300) >> 7) | 0x01;
+			if (brcmstb_i2c_write_data_byte(dev, &addr, 0) < 0)
+				return -EREMOTEIO;
+
+		}
+	} else {
+		addr = msg->addr << 1;
+		if (msg->flags & I2C_M_RD)
+			addr |= 1;
+
+		bsc_writel(dev, addr, chip_address);
+	}
+
+	return 0;
+}
+
+/* Master transfer function */
+static int brcmstb_i2c_xfer(struct i2c_adapter *adapter,
+			    struct i2c_msg msgs[], int num)
+{
+	struct brcmstb_i2c_dev *dev = i2c_get_adapdata(adapter);
+	struct i2c_msg *pmsg;
+	int rc = 0;
+	int i;
+	int bytes_to_xfer;
+	u8 *tmp_buf;
+	int len = 0;
+
+	if (dev->is_suspended)
+		return -EBUSY;
+
+	/* Loop through all messages */
+	for (i = 0; i < num; i++) {
+		pmsg = &msgs[i];
+		len = pmsg->len;
+		tmp_buf = pmsg->buf;
+
+		dev_dbg(dev->device,
+			"msg# %d/%d flg %x buf %x len %d\n", i,
+			num - 1, pmsg->flags,
+			pmsg->buf ? pmsg->buf[0] : '0', pmsg->len);
+
+		if (i < (num - 1) && (msgs[i + 1].flags & I2C_M_NOSTART))
+			brcmstb_set_i2c_start_stop(dev, ~(COND_START_STOP));
+		else
+			brcmstb_set_i2c_start_stop(dev,
+						   COND_RESTART | COND_NOSTOP);
+
+		/* Send slave address */
+		if (!(pmsg->flags & I2C_M_NOSTART)) {
+			rc = brcmstb_i2c_do_addr(dev, pmsg);
+			if (rc < 0) {
+				dev_dbg(dev->device,
+					"NACK for addr %2.2x msg#%d rc = %d\n",
+					pmsg->addr, i, rc);
+				goto out;
+			}
+		}
+
+		/* Perform data transfer */
+		while (len) {
+			bytes_to_xfer = min(len, N_DATA_BYTES);
+
+			if (len <= N_DATA_BYTES && i == (num - 1))
+				brcmstb_set_i2c_start_stop(dev,
+							   ~(COND_START_STOP));
+
+			rc = brcmstb_i2c_xfer_bsc_data(dev, tmp_buf,
+						       bytes_to_xfer, pmsg);
+			if (rc < 0)
+				goto out;
+
+			len -=  bytes_to_xfer;
+			tmp_buf += bytes_to_xfer;
+		}
+	}
+
+	rc = num;
+out:
+	return rc;
+
+}
+
+static u32 brcmstb_i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR
+		| I2C_FUNC_NOSTART | I2C_FUNC_PROTOCOL_MANGLING;
+}
+
+static const struct i2c_algorithm brcmstb_i2c_algo = {
+	.master_xfer = brcmstb_i2c_xfer,
+	.functionality = brcmstb_i2c_functionality,
+};
+
+static void brcmstb_i2c_set_bus_speed(struct brcmstb_i2c_dev *dev)
+{
+	int i = 0, num_speeds = ARRAY_SIZE(bsc_clk);
+	u32 clk_freq_hz = dev->clk_freq_hz;
+
+	for (i = 0; i < num_speeds; i++) {
+		if (bsc_clk[i].hz == clk_freq_hz) {
+			dev->bsc_regmap->ctl_reg &= ~(BSC_CTL_REG_SCL_SEL_MASK
+						| BSC_CTL_REG_DIV_CLK_MASK);
+			dev->bsc_regmap->ctl_reg |= (bsc_clk[i].scl_mask |
+						     bsc_clk[i].div_mask);
+			bsc_writel(dev, dev->bsc_regmap->ctl_reg, ctl_reg);
+			break;
+		}
+	}
+
+	/* in case we did not get find a valid speed */
+	if (i == num_speeds) {
+		i = (bsc_readl(dev, ctl_reg) & BSC_CTL_REG_SCL_SEL_MASK) >>
+			BSC_CTL_REG_SCL_SEL_SHIFT;
+		dev_warn(dev->device, "leaving current clock-frequency @ %dHz\n",
+			bsc_clk[i].hz);
+	}
+}
+
+static void brcmstb_i2c_set_bsc_reg_defaults(struct brcmstb_i2c_dev *dev)
+{
+	/* 4 byte data register */
+	dev->bsc_regmap->ctlhi_reg = BSC_CTLHI_REG_DATAREG_SIZE_MASK;
+	bsc_writel(dev, dev->bsc_regmap->ctlhi_reg, ctlhi_reg);
+	/* set bus speed */
+	brcmstb_i2c_set_bus_speed(dev);
+}
+
+static int brcmstb_i2c_probe(struct platform_device *pdev)
+{
+	int rc = 0;
+	struct brcmstb_i2c_dev *dev;
+	struct i2c_adapter *adap;
+	struct resource *iomem;
+	const char *int_name;
+
+	/* Allocate memory for private data structure */
+	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->bsc_regmap = devm_kzalloc(&pdev->dev, sizeof(struct bsc_regs *),
+				       GFP_KERNEL);
+	if (!dev->bsc_regmap)
+		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)) {
+		rc = -ENOMEM;
+		goto probe_errorout;
+	}
+
+	rc = of_property_read_string(dev->device->of_node, "interrupt-names",
+				     &int_name);
+	if (rc < 0)
+		int_name = NULL;
+
+	/* Get the interrupt number */
+	dev->irq = platform_get_irq(pdev, 0);
+
+	/* disable the bsc interrupt line */
+	brcmstb_i2c_enable_disable_irq(dev, INT_DISABLE);
+
+	/* register the ISR handler */
+	rc = devm_request_irq(&pdev->dev, dev->irq, brcmstb_i2c_isr,
+			      IRQF_SHARED,
+			      int_name ? int_name : pdev->name,
+			      dev);
+
+	if (rc) {
+		dev_dbg(dev->device, "falling back to polling mode");
+		dev->irq = -1;
+	}
+
+	if (of_property_read_u32(dev->device->of_node,
+				 "clock-frequency", &dev->clk_freq_hz)) {
+		dev_warn(dev->device, "setting clock-frequency@%dHz\n",
+			 bsc_clk[0].hz);
+		dev->clk_freq_hz = bsc_clk[0].hz;
+	}
+
+	brcmstb_i2c_set_bsc_reg_defaults(dev);
+
+	/* Add the i2c adapter */
+	adap = &dev->adapter;
+	i2c_set_adapdata(adap, dev);
+	adap->owner = THIS_MODULE;
+	strlcpy(adap->name, "Broadcom STB : ", sizeof(adap->name));
+	if (int_name)
+		strlcat(adap->name, int_name, sizeof(adap->name));
+	adap->algo = &brcmstb_i2c_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");
+		goto probe_errorout;
+	}
+
+	dev_info(dev->device, "%s@%dhz registered in %s mode\n",
+		 int_name ? int_name : " ", dev->clk_freq_hz,
+		 (dev->irq >= 0) ? "interrupt" : "polling");
+
+	return 0;
+
+probe_errorout:
+	return rc;
+}
+
+static int brcmstb_i2c_remove(struct platform_device *pdev)
+{
+	struct brcmstb_i2c_dev *dev = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&dev->adapter);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int brcmstb_i2c_suspend(struct device *dev)
+{
+	struct brcmstb_i2c_dev *i2c_dev = dev_get_drvdata(dev);
+
+	i2c_lock_adapter(&i2c_dev->adapter);
+	i2c_dev->is_suspended = true;
+	i2c_unlock_adapter(&i2c_dev->adapter);
+
+	return 0;
+}
+
+static int brcmstb_i2c_resume(struct device *dev)
+{
+	struct brcmstb_i2c_dev *i2c_dev = dev_get_drvdata(dev);
+
+	i2c_lock_adapter(&i2c_dev->adapter);
+	brcmstb_i2c_set_bsc_reg_defaults(i2c_dev);
+	i2c_dev->is_suspended = false;
+	i2c_unlock_adapter(&i2c_dev->adapter);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(brcmstb_i2c_pm, brcmstb_i2c_suspend,
+			 brcmstb_i2c_resume);
+
+static const struct of_device_id brcmstb_i2c_of_match[] = {
+	{.compatible = "brcm,brcmstb-i2c"},
+	{},
+};
+MODULE_DEVICE_TABLE(of, brcmstb_i2c_of_match);
+
+static struct platform_driver brcmstb_i2c_driver = {
+	.driver = {
+		   .name = "brcmstb-i2c",
+		   .owner = THIS_MODULE,
+		   .of_match_table = brcmstb_i2c_of_match,
+		   .pm = &brcmstb_i2c_pm,
+		   },
+	.probe = brcmstb_i2c_probe,
+	.remove = brcmstb_i2c_remove,
+};
+module_platform_driver(brcmstb_i2c_driver);
+
+MODULE_AUTHOR("Kamal Dasu <kdasu@broadcom.com>");
+MODULE_DESCRIPTION("Broadcom Settop I2C Driver");
+MODULE_LICENSE("GPL v2");