diff mbox

[v2,2/4] Added I2C_SLAVE as a dependency to I2C_DESIGNWARE_CORE Enable _slave() mode Review of the pm_runtime...() methods and cleaning

Message ID ffbbaeace295a28ade33aafde7f287c6bcc901eb.1476462204.git.lolivei@synopsys.com
State Superseded
Headers show

Commit Message

Luis de Oliveira Oct. 14, 2016, 4:52 p.m. UTC
From: Luis Oliveira <lolivei@synopsys.com>

Signed-off-by: Luis Oliveira <lolivei@synopsys.com>
---
 drivers/i2c/busses/Kconfig                  |   3 +-
 drivers/i2c/busses/i2c-designware-core.c    | 180 ++++++++++++++++++++++++++--
 drivers/i2c/busses/i2c-designware-core.h    |   6 +
 drivers/i2c/busses/i2c-designware-platdrv.c |  33 ++++-
 4 files changed, 212 insertions(+), 10 deletions(-)

Comments

Andy Shevchenko Oct. 21, 2016, 10:52 a.m. UTC | #1
On Fri, 2016-10-14 at 17:52 +0100, Luis.Oliveira@synopsys.com wrote:
> From: Luis Oliveira <lolivei@synopsys.com>
> 

Same style issues here and in the code itself. Check all your patches
before submitting.

More comments below.

> @@ -785,9 +817,59 @@ static u32 i2c_dw_func(struct i2c_adapter *adap)
>  	return dev->functionality;
>  }
>  
> +static int i2c_dw_reg_slave(struct i2c_client *slave)
> +{
> +	struct dw_i2c_dev *dev =  i2c_get_adapdata(slave->adapter);

Just '...dev = i2c...'.

> +

> +	if(dev->slave)
> +		return -EBUSY;

Hmm... Is it possible that function be called twice?

> +	if(slave->flags & I2C_CLIENT_TEN)
> +		return -EAFNOSUPPORT;
> +		/* set slave address in the IC_SAR register, 
> +		* the address to which the DW_apb_i2c responds */
> +
> +	__i2c_dw_enable(dev, false);
> +	
> +	dw_writel(dev, slave->addr, DW_IC_SAR);
> +
> +	pm_runtime_get_sync(dev->dev);
> +	

> +	dev->slave = slave;

So, you are using this variable to serialize the calls. Assume it's
possible that upper layer calls several time the function how you
protect the potential race here?

No need runtime PM for this line as well.

> +
> +	__i2c_dw_enable(dev, true);
> +
> +	dev->cmd_err = 0;
> +	dev->msg_write_idx = 0;
> +	dev->msg_read_idx = 0;
> +	dev->msg_err = 0;
> +	dev->status = STATUS_IDLE;
> +	dev->abort_source = 0;
> +	dev->rx_outstanding = 0;
> +
> +	return 0;
> +}
> +
> +static int i2c_dw_unreg_slave(struct i2c_client *slave)
> +{
> +	struct dw_i2c_dev *dev =  i2c_get_adapdata(slave->adapter);
> +

> +	WARN_ON(!dev->slave);

I'm not sure it's needed. Consider together with comment regarding
_reg_slave().

> +
> +	i2c_dw_disable_int(dev);
> +	i2c_dw_disable(dev);
> +

> +	dev->slave =  NULL;

Same comments as for _reg_slave().

> +
> +	pm_runtime_put(dev->dev);
> +
> +	return 0;
> +}
> +
>  static struct i2c_algorithm i2c_dw_algo = {
>  	.master_xfer	= i2c_dw_xfer,
>  	.functionality	= i2c_dw_func,
> +	.reg_slave	= i2c_dw_reg_slave,
> +	.unreg_slave	= i2c_dw_unreg_slave,
>  };
>  
>  static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
> @@ -821,8 +903,6 @@ static u32 i2c_dw_read_clear_intrbits(struct
> dw_i2c_dev *dev)
>  		dw_readl(dev, DW_IC_CLR_RX_OVER);
>  	if (stat & DW_IC_INTR_TX_OVER)
>  		dw_readl(dev, DW_IC_CLR_TX_OVER);
> -	if (stat & DW_IC_INTR_RD_REQ)
> -		dw_readl(dev, DW_IC_CLR_RD_REQ);
>  	if (stat & DW_IC_INTR_TX_ABRT) {
>  		/*
>  		 * The IC_TX_ABRT_SOURCE register is cleared whenever
> @@ -849,6 +929,84 @@ static u32 i2c_dw_read_clear_intrbits(struct
> dw_i2c_dev *dev)
>   * Interrupt service routine. This gets called whenever an I2C
> interrupt
>   * occurs.
>   */
> + 
> +static bool i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev )
> +{
> +	u32 raw_stat, stat, enabled;
> +	u8 val, slave_activity;
> +	
> +	stat = dw_readl(dev, DW_IC_INTR_STAT);
> +	enabled = dw_readl(dev, DW_IC_ENABLE);
> +	raw_stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
> +	slave_activity = ((dw_readl(dev,DW_IC_STATUS) & 
> +	DW_IC_STATUS_SLAVE_ACTIVITY)>>6);
> +		
> +	dev_dbg(dev->dev, 
> +	"%s: %#x SLAVE_ACTV=%#x : RAW_INTR_STAT=%#x :
> INTR_STAT=%#x\n", 
> +	 __func__, enabled, slave_activity, raw_stat, stat); 
> +
> +	if (stat & DW_IC_INTR_START_DET)
> +		dw_readl(dev, DW_IC_CLR_START_DET);
> +		
> +	if (stat & DW_IC_INTR_ACTIVITY)
> +		dw_readl(dev, DW_IC_CLR_ACTIVITY);
> +
> +	if (stat & DW_IC_INTR_RX_OVER)
> +		dw_readl(dev, DW_IC_CLR_RX_OVER);
> +	
> +       if ((stat & DW_IC_INTR_RX_FULL) && (stat &
> DW_IC_INTR_STOP_DET)) 
> +		i2c_slave_event(dev->slave,
> I2C_SLAVE_WRITE_REQUESTED, &val);
> +	
> +	if (slave_activity) {     
> +		if (stat & DW_IC_INTR_RD_REQ) {                 
> +			if (stat & DW_IC_INTR_RX_FULL) {
> +				val = dw_readl(dev, DW_IC_DATA_CMD);
> +				if (!i2c_slave_event(dev->slave, 
> +					I2C_SLAVE_WRITE_RECEIVED,
> &val)) {
> +					dev_dbg(dev->dev, "Byte %X
> acked! ",val);
> +				}
> +				dw_readl(dev, DW_IC_CLR_RD_REQ);
> +				stat =
> i2c_dw_read_clear_intrbits(dev);

> +			}
> +			else {

Style is '} else {'.

> +				dw_readl(dev, DW_IC_CLR_RD_REQ);
> +				dw_readl(dev, DW_IC_CLR_RX_UNDER);
> +				stat =
> i2c_dw_read_clear_intrbits(dev);
> +			}     
> +			if (!i2c_slave_event(dev->slave, 
> +					I2C_SLAVE_READ_REQUESTED,
> &val))
> +				dw_writel(dev, val, DW_IC_DATA_CMD);
> +		}
> +	}        
> +	
> +	if (stat & DW_IC_INTR_RX_DONE) {
> +		
> +		if (!i2c_slave_event(dev->slave,
> I2C_SLAVE_READ_PROCESSED, &val)) 
> +			dw_readl(dev, DW_IC_CLR_RX_DONE);
> +		
> +		i2c_slave_event(dev->slave, I2C_SLAVE_STOP , &val);
> +		stat = i2c_dw_read_clear_intrbits(dev);
> +
> +		return true;
> +	}
> +        
> +	if (stat & DW_IC_INTR_RX_FULL) { 
> +		val = dw_readl(dev, DW_IC_DATA_CMD);
> +		if (!i2c_slave_event(dev->slave,
> I2C_SLAVE_WRITE_RECEIVED, &val))
> +			dev_dbg(dev->dev, "Byte %X acked! ",val);
> +	} 
> +	else {
> +		i2c_slave_event(dev->slave, I2C_SLAVE_STOP , &val);
> +		stat = i2c_dw_read_clear_intrbits(dev);
> +	}
> +
> +	if (stat & DW_IC_INTR_TX_OVER) {		
> +		dw_readl(dev, DW_IC_CLR_TX_OVER);
> +		return true;
> +	}
> +
> +	return true;
> +}
>  
>  static bool i2c_dw_irq_handler_master(struct dw_i2c_dev *dev )
>  {
> @@ -910,14 +1068,20 @@ static irqreturn_t i2c_dw_isr(int this_irq,
> void *dev_id)
>  	enabled = dw_readl(dev, DW_IC_ENABLE);
>  	mode = dw_readl(dev, DW_IC_CON);
>  	stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
> -
> +	

Shouldn't be here.

>  	dev_dbg(dev->dev, "%s: enabled=%#x stat=%#x\n", __func__,
> enabled, stat);
>  	if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY))
>  		return IRQ_NONE;
> -
> +	

Ditto.

> +	if (!(mode & DW_IC_CON_MASTER) && !(mode &
> DW_IC_CON_SLAVE_DISABLE)) {
> +		stat = i2c_dw_read_clear_intrbits(dev);
> +		if (!i2c_dw_irq_handler_slave(dev))
> +			return IRQ_NONE;
> +	} else {
>  	if(i2c_dw_irq_handler_master(dev))
>  		return IRQ_HANDLED;

> -			

> +	}

> +

Ditto.

>  	complete(&dev->cmd_complete);
>  	return IRQ_HANDLED;
>  }
> @@ -984,7 +1148,9 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
>  	adap->dev.parent = dev->dev;
>  	i2c_set_adapdata(adap, dev);
>  
> -	i2c_dw_disable_int(dev);
> +	if (!i2c_check_functionality(adap,I2C_FUNC_SLAVE)) 
> +		i2c_dw_disable_int(dev);
> +
>  	r = devm_request_irq(dev->dev, dev->irq, i2c_dw_isr,
>  			     IRQF_SHARED | IRQF_COND_SUSPEND,
>  			     dev_name(dev->dev), dev);
> diff --git a/drivers/i2c/busses/i2c-designware-core.h
> b/drivers/i2c/busses/i2c-designware-core.h
> index 0d44d2a..de5e4a0 100644
> --- a/drivers/i2c/busses/i2c-designware-core.h
> +++ b/drivers/i2c/busses/i2c-designware-core.h
> @@ -28,9 +28,13 @@
>  #define DW_IC_CON_SPEED_FAST		0x4
>  #define DW_IC_CON_SPEED_HIGH		0x6
>  #define DW_IC_CON_SPEED_MASK		0x6
> +#define DW_IC_CON_10BITADDR_SLAVE       0x8
>  #define DW_IC_CON_10BITADDR_MASTER	0x10
>  #define DW_IC_CON_RESTART_EN		0x20
>  #define DW_IC_CON_SLAVE_DISABLE		0x40
> +#define DW_IC_CON_STOP_DET_IFADDRESSED  0x80
> +#define DW_IC_CON_TX_EMPTY_CTRL		0x100
> +#define DW_IC_CON_RX_FIFO_FULL_HLD_CTRL	0x200
>  

Is it possible to split your approach to something like:
1. Add necessary definitions (not actual code).
2. Enable slave.
diff mbox

Patch

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 6d94e2e..f93ad70 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -470,10 +470,11 @@  config I2C_DESIGNWARE_CORE
 config I2C_DESIGNWARE_PLATFORM
 	tristate "Synopsys DesignWare Platform"
 	select I2C_DESIGNWARE_CORE
+	select I2C_SLAVE
 	depends on (ACPI && COMMON_CLK) || !ACPI
 	help
 	  If you say yes to this option, support will be included for the
-	  Synopsys DesignWare I2C adapter. Only master mode is supported.
+	  Synopsys DesignWare I2C adapter.
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-designware-platform.
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index cc38329..71a377e 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -37,6 +37,7 @@ 
  */
 #define DW_IC_CON		0x0
 #define DW_IC_TAR		0x4
+#define DW_IC_SAR		0x8
 #define DW_IC_DATA_CMD		0x10
 #define DW_IC_SS_SCL_HCNT	0x14
 #define DW_IC_SS_SCL_LCNT	0x18
@@ -92,10 +93,16 @@ 
  
 #define DW_IC_INTR_MASTER_MASK		(DW_IC_INTR_DEFAULT_MASK | \
 					 DW_IC_INTR_TX_EMPTY)
-
+					 
+#define DW_IC_INTR_SLAVE_MASK		(DW_IC_INTR_DEFAULT_MASK | \
+					 DW_IC_INTR_RX_DONE | \
+                                    DW_IC_INTR_RX_UNDER | \
+                                    DW_IC_INTR_RD_REQ)
+					 
 #define DW_IC_STATUS_ACTIVITY		0x1
 #define DW_IC_STATUS_TFE		BIT(2)
 #define DW_IC_STATUS_MASTER_ACTIVITY	BIT(5)
+#define DW_IC_STATUS_SLAVE_ACTIVITY	BIT(6)
 
 #define DW_IC_ERR_TX_ABRT	0x1
 
@@ -130,6 +137,9 @@ 
 #define ABRT_10B_RD_NORSTRT	10
 #define ABRT_MASTER_DIS		11
 #define ARB_LOST		12
+#define ABRT_SLAVE_FLUSH_TXFIFO	13
+#define ABRT_SLAVE_ARBLOST	14
+#define ABRT_SLAVE_RD_INTX	15
 
 #define DW_IC_TX_ABRT_7B_ADDR_NOACK	(1UL << ABRT_7B_ADDR_NOACK)
 #define DW_IC_TX_ABRT_10ADDR1_NOACK	(1UL << ABRT_10ADDR1_NOACK)
@@ -142,6 +152,9 @@ 
 #define DW_IC_TX_ABRT_10B_RD_NORSTRT	(1UL << ABRT_10B_RD_NORSTRT)
 #define DW_IC_TX_ABRT_MASTER_DIS	(1UL << ABRT_MASTER_DIS)
 #define DW_IC_TX_ARB_LOST		(1UL << ARB_LOST)
+#define DW_IC_RX_ABRT_SLAVE_RD_INTX        (1UL << ABRT_SLAVE_RD_INTX)
+#define DW_IC_RX_ABRT_SLAVE_ARBLOST       (1UL << ABRT_SLAVE_ARBLOST)
+#define DW_IC_RX_ABRT_SLAVE_FLUSH_TXFIFO   (1UL << ABRT_SLAVE_FLUSH_TXFIFO)
 
 #define DW_IC_TX_ABRT_NOACK		(DW_IC_TX_ABRT_7B_ADDR_NOACK | \
 					 DW_IC_TX_ABRT_10ADDR1_NOACK | \
@@ -172,6 +185,12 @@  static char *abort_sources[] = {
 		"trying to use disabled adapter",
 	[ARB_LOST] =
 		"lost arbitration",
+	[ABRT_SLAVE_FLUSH_TXFIFO] =
+		"read command so flush old data in the TX FIFO",
+	[ABRT_SLAVE_ARBLOST] =
+		"slave lost the bus while transmitting data to a remote master",
+	[ABRT_SLAVE_RD_INTX] =
+		"slave request for data to be transmitted and",
 };
 
 static u32 dw_readl(struct dw_i2c_dev *dev, int offset)
@@ -214,6 +233,17 @@  static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev)
 		dw_writel(dev, DW_IC_INTR_MASTER_MASK, DW_IC_INTR_MASK);
 }
 
+static void i2c_dw_configure_fifo_slave(struct dw_i2c_dev *dev)
+{
+		/* Configure Tx/Rx FIFO threshold levels */
+		dw_writel(dev, 0, DW_IC_TX_TL);
+		dw_writel(dev, 0, DW_IC_RX_TL);
+
+		/* configure the i2c slave */
+		dw_writel(dev, dev->slave_cfg , DW_IC_CON);
+		dw_writel(dev, DW_IC_INTR_SLAVE_MASK, DW_IC_INTR_MASK);
+}
+
 static u32
 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset)
 {
@@ -447,6 +477,8 @@  int i2c_dw_init(struct dw_i2c_dev *dev)
 	if ((dev->master_cfg & DW_IC_CON_MASTER) &&
 		(dev->master_cfg & DW_IC_CON_SLAVE_DISABLE)) 
 		i2c_dw_configure_fifo_master(dev);
+	else
+		i2c_dw_configure_fifo_slave(dev);
 
 	i2c_dw_release_lock(dev);
 
@@ -785,9 +817,59 @@  static u32 i2c_dw_func(struct i2c_adapter *adap)
 	return dev->functionality;
 }
 
+static int i2c_dw_reg_slave(struct i2c_client *slave)
+{
+	struct dw_i2c_dev *dev =  i2c_get_adapdata(slave->adapter);
+
+	if(dev->slave)
+		return -EBUSY;
+	if(slave->flags & I2C_CLIENT_TEN)
+		return -EAFNOSUPPORT;
+		/* set slave address in the IC_SAR register, 
+		* the address to which the DW_apb_i2c responds */
+
+	__i2c_dw_enable(dev, false);
+	
+	dw_writel(dev, slave->addr, DW_IC_SAR);
+
+	pm_runtime_get_sync(dev->dev);
+	
+	dev->slave = slave;
+
+	__i2c_dw_enable(dev, true);
+
+	dev->cmd_err = 0;
+	dev->msg_write_idx = 0;
+	dev->msg_read_idx = 0;
+	dev->msg_err = 0;
+	dev->status = STATUS_IDLE;
+	dev->abort_source = 0;
+	dev->rx_outstanding = 0;
+
+	return 0;
+}
+
+static int i2c_dw_unreg_slave(struct i2c_client *slave)
+{
+	struct dw_i2c_dev *dev =  i2c_get_adapdata(slave->adapter);
+
+	WARN_ON(!dev->slave);
+
+	i2c_dw_disable_int(dev);
+	i2c_dw_disable(dev);
+
+	dev->slave =  NULL;
+
+	pm_runtime_put(dev->dev);
+
+	return 0;
+}
+
 static struct i2c_algorithm i2c_dw_algo = {
 	.master_xfer	= i2c_dw_xfer,
 	.functionality	= i2c_dw_func,
+	.reg_slave	= i2c_dw_reg_slave,
+	.unreg_slave	= i2c_dw_unreg_slave,
 };
 
 static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
@@ -821,8 +903,6 @@  static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
 		dw_readl(dev, DW_IC_CLR_RX_OVER);
 	if (stat & DW_IC_INTR_TX_OVER)
 		dw_readl(dev, DW_IC_CLR_TX_OVER);
-	if (stat & DW_IC_INTR_RD_REQ)
-		dw_readl(dev, DW_IC_CLR_RD_REQ);
 	if (stat & DW_IC_INTR_TX_ABRT) {
 		/*
 		 * The IC_TX_ABRT_SOURCE register is cleared whenever
@@ -849,6 +929,84 @@  static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
  * Interrupt service routine. This gets called whenever an I2C interrupt
  * occurs.
  */
+ 
+static bool i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev )
+{
+	u32 raw_stat, stat, enabled;
+	u8 val, slave_activity;
+	
+	stat = dw_readl(dev, DW_IC_INTR_STAT);
+	enabled = dw_readl(dev, DW_IC_ENABLE);
+	raw_stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
+	slave_activity = ((dw_readl(dev,DW_IC_STATUS) & 
+	DW_IC_STATUS_SLAVE_ACTIVITY)>>6);
+		
+	dev_dbg(dev->dev, 
+	"%s: %#x SLAVE_ACTV=%#x : RAW_INTR_STAT=%#x : INTR_STAT=%#x\n", 
+	 __func__, enabled, slave_activity, raw_stat, stat); 
+
+	if (stat & DW_IC_INTR_START_DET)
+		dw_readl(dev, DW_IC_CLR_START_DET);
+		
+	if (stat & DW_IC_INTR_ACTIVITY)
+		dw_readl(dev, DW_IC_CLR_ACTIVITY);
+
+	if (stat & DW_IC_INTR_RX_OVER)
+		dw_readl(dev, DW_IC_CLR_RX_OVER);
+	
+       if ((stat & DW_IC_INTR_RX_FULL) && (stat & DW_IC_INTR_STOP_DET)) 
+		i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED, &val);
+	
+	if (slave_activity) {     
+		if (stat & DW_IC_INTR_RD_REQ) {                 
+			if (stat & DW_IC_INTR_RX_FULL) {
+				val = dw_readl(dev, DW_IC_DATA_CMD);
+				if (!i2c_slave_event(dev->slave, 
+					I2C_SLAVE_WRITE_RECEIVED, &val)) {
+					dev_dbg(dev->dev, "Byte %X acked! ",val);
+				}
+				dw_readl(dev, DW_IC_CLR_RD_REQ);
+				stat = i2c_dw_read_clear_intrbits(dev);
+			}
+			else {
+				dw_readl(dev, DW_IC_CLR_RD_REQ);
+				dw_readl(dev, DW_IC_CLR_RX_UNDER);
+				stat = i2c_dw_read_clear_intrbits(dev);
+			}     
+			if (!i2c_slave_event(dev->slave, 
+					I2C_SLAVE_READ_REQUESTED, &val))
+				dw_writel(dev, val, DW_IC_DATA_CMD);
+		}
+	}        
+	
+	if (stat & DW_IC_INTR_RX_DONE) {
+		
+		if (!i2c_slave_event(dev->slave, I2C_SLAVE_READ_PROCESSED, &val)) 
+			dw_readl(dev, DW_IC_CLR_RX_DONE);
+		
+		i2c_slave_event(dev->slave, I2C_SLAVE_STOP , &val);
+		stat = i2c_dw_read_clear_intrbits(dev);
+
+		return true;
+	}
+        
+	if (stat & DW_IC_INTR_RX_FULL) { 
+		val = dw_readl(dev, DW_IC_DATA_CMD);
+		if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED, &val))
+			dev_dbg(dev->dev, "Byte %X acked! ",val);
+	} 
+	else {
+		i2c_slave_event(dev->slave, I2C_SLAVE_STOP , &val);
+		stat = i2c_dw_read_clear_intrbits(dev);
+	}
+
+	if (stat & DW_IC_INTR_TX_OVER) {		
+		dw_readl(dev, DW_IC_CLR_TX_OVER);
+		return true;
+	}
+
+	return true;
+}
 
 static bool i2c_dw_irq_handler_master(struct dw_i2c_dev *dev )
 {
@@ -910,14 +1068,20 @@  static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
 	enabled = dw_readl(dev, DW_IC_ENABLE);
 	mode = dw_readl(dev, DW_IC_CON);
 	stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
-
+	
 	dev_dbg(dev->dev, "%s: enabled=%#x stat=%#x\n", __func__, enabled, stat);
 	if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY))
 		return IRQ_NONE;
-
+	
+	if (!(mode & DW_IC_CON_MASTER) && !(mode & DW_IC_CON_SLAVE_DISABLE)) {
+		stat = i2c_dw_read_clear_intrbits(dev);
+		if (!i2c_dw_irq_handler_slave(dev))
+			return IRQ_NONE;
+	} else {
 	if(i2c_dw_irq_handler_master(dev))
 		return IRQ_HANDLED;
-			
+	}
+
 	complete(&dev->cmd_complete);
 	return IRQ_HANDLED;
 }
@@ -984,7 +1148,9 @@  int i2c_dw_probe(struct dw_i2c_dev *dev)
 	adap->dev.parent = dev->dev;
 	i2c_set_adapdata(adap, dev);
 
-	i2c_dw_disable_int(dev);
+	if (!i2c_check_functionality(adap,I2C_FUNC_SLAVE)) 
+		i2c_dw_disable_int(dev);
+
 	r = devm_request_irq(dev->dev, dev->irq, i2c_dw_isr,
 			     IRQF_SHARED | IRQF_COND_SUSPEND,
 			     dev_name(dev->dev), dev);
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 0d44d2a..de5e4a0 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -28,9 +28,13 @@ 
 #define DW_IC_CON_SPEED_FAST		0x4
 #define DW_IC_CON_SPEED_HIGH		0x6
 #define DW_IC_CON_SPEED_MASK		0x6
+#define DW_IC_CON_10BITADDR_SLAVE       0x8
 #define DW_IC_CON_10BITADDR_MASTER	0x10
 #define DW_IC_CON_RESTART_EN		0x20
 #define DW_IC_CON_SLAVE_DISABLE		0x40
+#define DW_IC_CON_STOP_DET_IFADDRESSED  0x80
+#define DW_IC_CON_TX_EMPTY_CTRL		0x100
+#define DW_IC_CON_RX_FIFO_FULL_HLD_CTRL	0x200
 
 
 /**
@@ -80,6 +84,7 @@  struct dw_i2c_dev {
 	void __iomem		*base;
 	struct completion	cmd_complete;
 	struct clk		*clk;
+	struct i2c_client		*slave;
 	u32			(*get_clk_rate_khz) (struct dw_i2c_dev *dev);
 	struct dw_pci_controller *controller;
 	int			cmd_err;
@@ -99,6 +104,7 @@  struct dw_i2c_dev {
 	struct i2c_adapter	adapter;
 	u32			functionality;
 	u32			master_cfg;
+	u32			slave_cfg;
 	unsigned int		tx_fifo_depth;
 	unsigned int		rx_fifo_depth;
 	int			rx_outstanding;
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index d5986c2..b9076da 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -161,6 +161,30 @@  static void i2c_dw_configure_master(struct platform_device *pdev)
 	
 }
 
+static void i2c_dw_configure_slave(struct platform_device *pdev)
+{
+	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
+	
+	dev->slave_cfg = DW_IC_CON_RX_FIFO_FULL_HLD_CTRL | 
+			  DW_IC_CON_RESTART_EN | DW_IC_CON_STOP_DET_IFADDRESSED | 
+			  DW_IC_CON_SPEED_FAST;
+		  
+	dev->functionality |= I2C_FUNC_SLAVE;
+	dev->functionality &= ~I2C_FUNC_10BIT_ADDR;
+	dev_info(&pdev->dev, "I am registed as a I2C Slave!\n");
+	
+	switch (dev->clk_freq) {
+	case 100000:
+		dev->slave_cfg |= DW_IC_CON_SPEED_STD;
+		
+	case 3400000:
+		dev->slave_cfg |= DW_IC_CON_SPEED_HIGH;
+		break;
+	default:
+		dev->slave_cfg |= DW_IC_CON_SPEED_FAST;
+	}
+}
+
 static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
 {
 	if (IS_ERR(i_dev->clk))
@@ -181,6 +205,7 @@  static int dw_i2c_plat_probe(struct platform_device *pdev)
 	struct resource *mem;
 	int irq, r;
 	u32 acpi_speed, ht = 0;
+	bool is_slave = false;
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
@@ -213,6 +238,7 @@  static int dw_i2c_plat_probe(struct platform_device *pdev)
 					 &dev->scl_falling_time);
 		device_property_read_u32(&pdev->dev, "clock-frequency",
 					 &dev->clk_freq);
+		is_slave = device_property_read_bool(&pdev->dev, "isslave");
 	}
 
 	acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
@@ -244,8 +270,11 @@  static int dw_i2c_plat_probe(struct platform_device *pdev)
 		I2C_FUNC_SMBUS_BYTE_DATA |
 		I2C_FUNC_SMBUS_WORD_DATA |
 		I2C_FUNC_SMBUS_I2C_BLOCK;
-
-	i2c_dw_configure_master(pdev);
+	
+	if (is_slave)
+		i2c_dw_configure_slave(pdev);
+	else 
+		i2c_dw_configure_master(pdev);
 
 	dev->clk = devm_clk_get(&pdev->dev, NULL);
 	if (!i2c_dw_plat_prepare_clk(dev, true)) {