[PATCH 1/6] i2c: davinci: Fix smbus Oops with AIC33 usage

[PATCH 1/6] i2c: davinci: Fix smbus Oops with AIC33 usage

[Kevin Hilman]

From: Dirk Behme <dirk.behme@googlemail.com>

This fixes Oops at kernel startup while "scanning" for TLV320AIC23IDx
addresses.

Additional fix from Sudhakar Rajashekhara: I think 'first byte set'
should come after the write because an I2C transaction is being
carried out before configuring the I2C mode register (which has bits
to configure Master, Start condition etc), which causes undefined
behavior.

Signed-off-by: Sudhakar Rajashekhara <sudhakar.raj@ti.com>
Signed-off-by: Alexander Vasiliev <alexvasiljev@gmail.com>
Signed-off-by: Brad Griffis <bgriffis@ti.com>
Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
---
 drivers/i2c/busses/i2c-davinci.c |   31 +++++++++++++++++++++++++++----
 1 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index c89687a..3b9ab23 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -112,6 +112,7 @@ struct davinci_i2c_dev {
 	u8			*buf;
 	size_t			buf_len;
 	int			irq;
+	int			stop;
 	u8			terminate;
 	struct i2c_adapter	adapter;
 };
@@ -249,9 +250,6 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 	u16 w;
 	int r;
 
-	if (msg->len == 0)
-		return -EINVAL;
-
 	if (!pdata)
 		pdata = &davinci_i2c_platform_data_default;
 	/* Introduce a delay, required for some boards (e.g Davinci EVM) */
@@ -263,6 +261,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 
 	dev->buf = msg->buf;
 	dev->buf_len = msg->len;
+	dev->stop = stop;
 
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
 
@@ -280,6 +279,10 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 		flag |= DAVINCI_I2C_MDR_TRX;
 	if (stop)
 		flag |= DAVINCI_I2C_MDR_STP;
+	if (msg->len == 0) {
+		flag |= DAVINCI_I2C_MDR_RM;
+		flag &= ~DAVINCI_I2C_MDR_STP;
+	}
 
 	/* Enable receive or transmit interrupts */
 	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
@@ -290,9 +293,21 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
 
 	dev->terminate = 0;
+
 	/* write the data into mode register */
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 
+	/*
+	 * First byte should be set here, not after interrupt,
+	 * because transmit-data-ready interrupt can come before
+	 * NACK-interrupt during sending of previous message and
+	 * ICDXR may have wrong data
+	 */
+	if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
+		davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
+		dev->buf_len--;
+	}
+
 	r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
 						      dev->adapter.timeout);
 	if (r == 0) {
@@ -371,7 +386,7 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 
 static u32 i2c_davinci_func(struct i2c_adapter *adap)
 {
-	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }
 
 static void terminate_read(struct davinci_i2c_dev *dev)
@@ -430,6 +445,14 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
 		case DAVINCI_I2C_IVR_ARDY:
 			davinci_i2c_write_reg(dev,
 				DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
+			if (((dev->buf_len == 0) && (dev->stop != 0)) ||
+			    (dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
+				w = davinci_i2c_read_reg(dev,
+							 DAVINCI_I2C_MDR_REG);
+				w |= DAVINCI_I2C_MDR_STP;
+				davinci_i2c_write_reg(dev,
+						      DAVINCI_I2C_MDR_REG, w);
+			}
 			complete(&dev->cmd_complete);
 			break;
 
-- 
1.7.0.2

Re: [PATCH 1/6] i2c: davinci: Fix smbus Oops with AIC33 usage

[Ben Dooks]

On Tue, Apr 06, 2010 at 10:42:13AM -0700, Kevin Hilman wrote:
> From: Dirk Behme <dirk.behme@googlemail.com>
> 
> This fixes Oops at kernel startup while "scanning" for TLV320AIC23IDx
> addresses.

this looks like it could be a candidate for -rc?
 
> Additional fix from Sudhakar Rajashekhara: I think 'first byte set'
> should come after the write because an I2C transaction is being
> carried out before configuring the I2C mode register (which has bits
> to configure Master, Start condition etc), which causes undefined
> behavior.
> 
> Signed-off-by: Sudhakar Rajashekhara <sudhakar.raj@ti.com>
> Signed-off-by: Alexander Vasiliev <alexvasiljev@gmail.com>
> Signed-off-by: Brad Griffis <bgriffis@ti.com>
> Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
> Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
> ---
>  drivers/i2c/busses/i2c-davinci.c |   31 +++++++++++++++++++++++++++----
>  1 files changed, 27 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
> index c89687a..3b9ab23 100644
> --- a/drivers/i2c/busses/i2c-davinci.c
> +++ b/drivers/i2c/busses/i2c-davinci.c
> @@ -112,6 +112,7 @@ struct davinci_i2c_dev {
>  	u8			*buf;
>  	size_t			buf_len;
>  	int			irq;
> +	int			stop;
>  	u8			terminate;
>  	struct i2c_adapter	adapter;
>  };
> @@ -249,9 +250,6 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
>  	u16 w;
>  	int r;
>  
> -	if (msg->len == 0)
> -		return -EINVAL;
> -
>  	if (!pdata)
>  		pdata = &davinci_i2c_platform_data_default;
>  	/* Introduce a delay, required for some boards (e.g Davinci EVM) */
> @@ -263,6 +261,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
>  
>  	dev->buf = msg->buf;
>  	dev->buf_len = msg->len;
> +	dev->stop = stop;
>  
>  	davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
>  
> @@ -280,6 +279,10 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
>  		flag |= DAVINCI_I2C_MDR_TRX;
>  	if (stop)
>  		flag |= DAVINCI_I2C_MDR_STP;
> +	if (msg->len == 0) {
> +		flag |= DAVINCI_I2C_MDR_RM;
> +		flag &= ~DAVINCI_I2C_MDR_STP;
> +	}
>  
>  	/* Enable receive or transmit interrupts */
>  	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
> @@ -290,9 +293,21 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
>  	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
>  
>  	dev->terminate = 0;
> +
>  	/* write the data into mode register */
>  	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
>  
> +	/*
> +	 * First byte should be set here, not after interrupt,
> +	 * because transmit-data-ready interrupt can come before
> +	 * NACK-interrupt during sending of previous message and
> +	 * ICDXR may have wrong data
> +	 */
> +	if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
> +		davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
> +		dev->buf_len--;
> +	}
> +
>  	r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
>  						      dev->adapter.timeout);
>  	if (r == 0) {
> @@ -371,7 +386,7 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>  
>  static u32 i2c_davinci_func(struct i2c_adapter *adap)
>  {
> -	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
> +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
>  }
>  
>  static void terminate_read(struct davinci_i2c_dev *dev)
> @@ -430,6 +445,14 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
>  		case DAVINCI_I2C_IVR_ARDY:
>  			davinci_i2c_write_reg(dev,
>  				DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
> +			if (((dev->buf_len == 0) && (dev->stop != 0)) ||
> +			    (dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
> +				w = davinci_i2c_read_reg(dev,
> +							 DAVINCI_I2C_MDR_REG);
> +				w |= DAVINCI_I2C_MDR_STP;
> +				davinci_i2c_write_reg(dev,
> +						      DAVINCI_I2C_MDR_REG, w);
> +			}
>  			complete(&dev->cmd_complete);
>  			break;
>  
> -- 
> 1.7.0.2
> 
> --
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> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Ben (ben@fluff.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

[PATCH 2/6] i2c: davinci: misc. cleanups: remove MOD_REG_BIT and IO_ADDRESS usage

[Kevin Hilman]

From: Chaithrika U S <chaithrika@ti.com>

Cleanup the DaVinci I2C driver. Remove MOD_REG_BIT macro.
Also use ioremap instead of IO_ADDRESS macro.

Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
---
 drivers/i2c/busses/i2c-davinci.c |   77 +++++++++++++++++++-------------------
 1 files changed, 38 insertions(+), 39 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 3b9ab23..9327cc9 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -37,7 +37,6 @@
 #include <linux/io.h>
 
 #include <mach/hardware.h>
-
 #include <mach/i2c.h>
 
 /* ----- global defines ----------------------------------------------- */
@@ -71,37 +70,29 @@
 #define DAVINCI_I2C_IVR_NACK	0x02
 #define DAVINCI_I2C_IVR_AL	0x01
 
-#define DAVINCI_I2C_STR_BB	(1 << 12)
-#define DAVINCI_I2C_STR_RSFULL	(1 << 11)
-#define DAVINCI_I2C_STR_SCD	(1 << 5)
-#define DAVINCI_I2C_STR_ARDY	(1 << 2)
-#define DAVINCI_I2C_STR_NACK	(1 << 1)
-#define DAVINCI_I2C_STR_AL	(1 << 0)
-
-#define DAVINCI_I2C_MDR_NACK	(1 << 15)
-#define DAVINCI_I2C_MDR_STT	(1 << 13)
-#define DAVINCI_I2C_MDR_STP	(1 << 11)
-#define DAVINCI_I2C_MDR_MST	(1 << 10)
-#define DAVINCI_I2C_MDR_TRX	(1 << 9)
-#define DAVINCI_I2C_MDR_XA	(1 << 8)
-#define DAVINCI_I2C_MDR_RM	(1 << 7)
-#define DAVINCI_I2C_MDR_IRS	(1 << 5)
-
-#define DAVINCI_I2C_IMR_AAS	(1 << 6)
-#define DAVINCI_I2C_IMR_SCD	(1 << 5)
-#define DAVINCI_I2C_IMR_XRDY	(1 << 4)
-#define DAVINCI_I2C_IMR_RRDY	(1 << 3)
-#define DAVINCI_I2C_IMR_ARDY	(1 << 2)
-#define DAVINCI_I2C_IMR_NACK	(1 << 1)
-#define DAVINCI_I2C_IMR_AL	(1 << 0)
-
-#define MOD_REG_BIT(val, mask, set) do { \
-	if (set) { \
-		val |= mask; \
-	} else { \
-		val &= ~mask; \
-	} \
-} while (0)
+#define DAVINCI_I2C_STR_BB	BIT(12)
+#define DAVINCI_I2C_STR_RSFULL	BIT(11)
+#define DAVINCI_I2C_STR_SCD	BIT(5)
+#define DAVINCI_I2C_STR_ARDY	BIT(2)
+#define DAVINCI_I2C_STR_NACK	BIT(1)
+#define DAVINCI_I2C_STR_AL	BIT(0)
+
+#define DAVINCI_I2C_MDR_NACK	BIT(15)
+#define DAVINCI_I2C_MDR_STT	BIT(13)
+#define DAVINCI_I2C_MDR_STP	BIT(11)
+#define DAVINCI_I2C_MDR_MST	BIT(10)
+#define DAVINCI_I2C_MDR_TRX	BIT(9)
+#define DAVINCI_I2C_MDR_XA	BIT(8)
+#define DAVINCI_I2C_MDR_RM	BIT(7)
+#define DAVINCI_I2C_MDR_IRS	BIT(5)
+
+#define DAVINCI_I2C_IMR_AAS	BIT(6)
+#define DAVINCI_I2C_IMR_SCD	BIT(5)
+#define DAVINCI_I2C_IMR_XRDY	BIT(4)
+#define DAVINCI_I2C_IMR_RRDY	BIT(3)
+#define DAVINCI_I2C_IMR_ARDY	BIT(2)
+#define DAVINCI_I2C_IMR_NACK	BIT(1)
+#define DAVINCI_I2C_IMR_AL	BIT(0)
 
 struct davinci_i2c_dev {
 	struct device           *dev;
@@ -155,7 +146,7 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 
 	/* put I2C into reset */
 	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-	MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 0);
+	w &= ~DAVINCI_I2C_MDR_IRS;
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 
 	/* NOTE: I2C Clock divider programming info
@@ -205,7 +196,7 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 
 	/* Take the I2C module out of reset: */
 	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-	MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 1);
+	w |= DAVINCI_I2C_MDR_IRS;
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 
 	/* Enable interrupts */
@@ -287,9 +278,9 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 	/* Enable receive or transmit interrupts */
 	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
 	if (msg->flags & I2C_M_RD)
-		MOD_REG_BIT(w, DAVINCI_I2C_IMR_RRDY, 1);
+		w |= DAVINCI_I2C_IMR_RRDY;
 	else
-		MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1);
+		w |= DAVINCI_I2C_IMR_XRDY;
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
 
 	dev->terminate = 0;
@@ -348,7 +339,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 			return msg->len;
 		if (stop) {
 			w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-			MOD_REG_BIT(w, DAVINCI_I2C_MDR_STP, 1);
+			w |= DAVINCI_I2C_MDR_STP;
 			davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 		}
 		return -EREMOTEIO;
@@ -484,7 +475,7 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
 
 				w = davinci_i2c_read_reg(dev,
 							 DAVINCI_I2C_IMR_REG);
-				MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 0);
+				w &= ~DAVINCI_I2C_IMR_XRDY;
 				davinci_i2c_write_reg(dev,
 						      DAVINCI_I2C_IMR_REG,
 						      w);
@@ -563,7 +554,12 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 	}
 	clk_enable(dev->clk);
 
-	dev->base = (void __iomem *)IO_ADDRESS(mem->start);
+	dev->base = ioremap(mem->start, resource_size(mem));
+	if (!dev->base) {
+		r = -EBUSY;
+		goto err_mem_ioremap;
+	}
+
 	i2c_davinci_init(dev);
 
 	r = request_irq(dev->irq, i2c_davinci_isr, 0, pdev->name, dev);
@@ -593,6 +589,8 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 err_free_irq:
 	free_irq(dev->irq, dev);
 err_unuse_clocks:
+	iounmap(dev->base);
+err_mem_ioremap:
 	clk_disable(dev->clk);
 	clk_put(dev->clk);
 	dev->clk = NULL;
@@ -621,6 +619,7 @@ static int davinci_i2c_remove(struct platform_device *pdev)
 
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
 	free_irq(IRQ_I2C, dev);
+	iounmap(dev->base);
 	kfree(dev);
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-- 
1.7.0.2

[PATCH 3/6] i2c: davinci: Add helper functions for power management

[Kevin Hilman]

From: Chaithrika U S <chaithrika@ti.com>

Add i2c reset control and clock divider calculation functions
which will be useful for power management features.

Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
---
 drivers/i2c/busses/i2c-davinci.c |   56 +++++++++++++++++++++++++-------------
 1 files changed, 37 insertions(+), 19 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 9327cc9..9239d2b 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -125,12 +125,21 @@ static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
 	return __raw_readw(i2c_dev->base + reg);
 }
 
-/*
- * This functions configures I2C and brings I2C out of reset.
- * This function is called during I2C init function. This function
- * also gets called if I2C encounters any errors.
- */
-static int i2c_davinci_init(struct davinci_i2c_dev *dev)
+static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
+								int val)
+{
+	u16 w;
+
+	w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG);
+	if (!val)	/* put I2C into reset */
+		w &= ~DAVINCI_I2C_MDR_IRS;
+	else		/* take I2C out of reset */
+		w |= DAVINCI_I2C_MDR_IRS;
+
+	davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w);
+}
+
+static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
 {
 	struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
 	u16 psc;
@@ -139,15 +148,6 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 	u32 clkh;
 	u32 clkl;
 	u32 input_clock = clk_get_rate(dev->clk);
-	u16 w;
-
-	if (!pdata)
-		pdata = &davinci_i2c_platform_data_default;
-
-	/* put I2C into reset */
-	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-	w &= ~DAVINCI_I2C_MDR_IRS;
-	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 
 	/* NOTE: I2C Clock divider programming info
 	 * As per I2C specs the following formulas provide prescaler
@@ -179,12 +179,32 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
 
+	dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
+}
+
+/*
+ * This function configures I2C and brings I2C out of reset.
+ * This function is called during I2C init function. This function
+ * also gets called if I2C encounters any errors.
+ */
+static int i2c_davinci_init(struct davinci_i2c_dev *dev)
+{
+	struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
+
+	if (!pdata)
+		pdata = &davinci_i2c_platform_data_default;
+
+	/* put I2C into reset */
+	davinci_i2c_reset_ctrl(dev, 0);
+
+	/* compute clock dividers */
+	i2c_davinci_calc_clk_dividers(dev);
+
 	/* Respond at reserved "SMBus Host" slave address" (and zero);
 	 * we seem to have no option to not respond...
 	 */
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
 
-	dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
 	dev_dbg(dev->dev, "PSC  = %d\n",
 		davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
 	dev_dbg(dev->dev, "CLKL = %d\n",
@@ -195,9 +215,7 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 		pdata->bus_freq, pdata->bus_delay);
 
 	/* Take the I2C module out of reset: */
-	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-	w |= DAVINCI_I2C_MDR_IRS;
-	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
+	davinci_i2c_reset_ctrl(dev, 1);
 
 	/* Enable interrupts */
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
-- 
1.7.0.2

[PATCH 4/6] i2c: davinci: Add suspend/resume support

[Kevin Hilman]

From: Chaithrika U S <chaithrika@ti.com>

Add suspend and resume callbacks to DaVinci I2C driver.
This has been tested on DA850/OMAP-L138 EVM.

Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
---
 drivers/i2c/busses/i2c-davinci.c |   36 ++++++++++++++++++++++++++++++++++++
 1 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 9239d2b..dfec296 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -645,6 +645,41 @@ static int davinci_i2c_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_PM
+static int davinci_i2c_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+
+	/* put I2C into reset */
+	davinci_i2c_reset_ctrl(i2c_dev, 0);
+	clk_disable(i2c_dev->clk);
+
+	return 0;
+}
+
+static int davinci_i2c_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+
+	clk_enable(i2c_dev->clk);
+	/* take I2C out of reset */
+	davinci_i2c_reset_ctrl(i2c_dev, 1);
+
+	return 0;
+}
+
+static const struct dev_pm_ops davinci_i2c_pm = {
+	.suspend        = davinci_i2c_suspend,
+	.resume         = davinci_i2c_resume,
+};
+
+#define davinci_i2c_pm_ops (&davinci_i2c_pm)
+#else
+#define davinci_i2c_pm_ops NULL
+#endif
+
 /* work with hotplug and coldplug */
 MODULE_ALIAS("platform:i2c_davinci");
 
@@ -654,6 +689,7 @@ static struct platform_driver davinci_i2c_driver = {
 	.driver		= {
 		.name	= "i2c_davinci",
 		.owner	= THIS_MODULE,
+		.pm	= davinci_i2c_pm_ops,
 	},
 };
 
-- 
1.7.0.2

[PATCH 5/6] i2c: davinci: Add cpufreq support

[Kevin Hilman]

From: Chaithrika U S <chaithrika@ti.com>

Add cpufreq support for DaVinci I2C driver.
Tested on DA850/OMAP-L138 EVM.

Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
---
 drivers/i2c/busses/i2c-davinci.c |   63 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 63 insertions(+), 0 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index dfec296..fd7a155 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -35,6 +35,7 @@
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
+#include <linux/cpufreq.h>
 
 #include <mach/hardware.h>
 #include <mach/i2c.h>
@@ -106,6 +107,10 @@ struct davinci_i2c_dev {
 	int			stop;
 	u8			terminate;
 	struct i2c_adapter	adapter;
+#ifdef CONFIG_CPU_FREQ
+	struct completion	xfr_complete;
+	struct notifier_block	freq_transition;
+#endif
 };
 
 /* default platform data to use if not supplied in the platform_device */
@@ -390,6 +395,11 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 		if (ret < 0)
 			return ret;
 	}
+
+#ifdef CONFIG_CPU_FREQ
+	complete(&dev->xfr_complete);
+#endif
+
 	return num;
 }
 
@@ -522,6 +532,48 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
 	return count ? IRQ_HANDLED : IRQ_NONE;
 }
 
+#ifdef CONFIG_CPU_FREQ
+static int i2c_davinci_cpufreq_transition(struct notifier_block *nb,
+				     unsigned long val, void *data)
+{
+	struct davinci_i2c_dev *dev;
+
+	dev = container_of(nb, struct davinci_i2c_dev, freq_transition);
+	if (val == CPUFREQ_PRECHANGE) {
+		wait_for_completion(&dev->xfr_complete);
+		davinci_i2c_reset_ctrl(dev, 0);
+	} else if (val == CPUFREQ_POSTCHANGE) {
+		i2c_davinci_calc_clk_dividers(dev);
+		davinci_i2c_reset_ctrl(dev, 1);
+	}
+
+	return 0;
+}
+
+static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
+{
+	dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition;
+
+	return cpufreq_register_notifier(&dev->freq_transition,
+					 CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
+{
+	cpufreq_unregister_notifier(&dev->freq_transition,
+				    CPUFREQ_TRANSITION_NOTIFIER);
+}
+#else
+static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
+{
+	return 0;
+}
+
+static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
+{
+}
+#endif
+
 static struct i2c_algorithm i2c_davinci_algo = {
 	.master_xfer	= i2c_davinci_xfer,
 	.functionality	= i2c_davinci_func,
@@ -561,6 +613,9 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 	}
 
 	init_completion(&dev->cmd_complete);
+#ifdef CONFIG_CPU_FREQ
+	init_completion(&dev->xfr_complete);
+#endif
 	dev->dev = get_device(&pdev->dev);
 	dev->irq = irq->start;
 	platform_set_drvdata(pdev, dev);
@@ -586,6 +641,12 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 		goto err_unuse_clocks;
 	}
 
+	r = i2c_davinci_cpufreq_register(dev);
+	if (r) {
+		dev_err(&pdev->dev, "failed to register cpufreq\n");
+		goto err_free_irq;
+	}
+
 	adap = &dev->adapter;
 	i2c_set_adapdata(adap, dev);
 	adap->owner = THIS_MODULE;
@@ -627,6 +688,8 @@ static int davinci_i2c_remove(struct platform_device *pdev)
 	struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
 	struct resource *mem;
 
+	i2c_davinci_cpufreq_deregister(dev);
+
 	platform_set_drvdata(pdev, NULL);
 	i2c_del_adapter(&dev->adapter);
 	put_device(&pdev->dev);
-- 
1.7.0.2

[PATCH 6/6] i2c: davinci: bus recovery procedure to clear the bus

[Kevin Hilman]

From: Philby John <pjohn@in.mvista.com>

Come out of i2c time out condition by following the
bus recovery procedure outlined in the i2c protocol v3 spec.
The kernel must be robust enough to gracefully recover
from i2c bus failure without having to reset the machine.
This is done by first NACKing the slave, pulsing the SCL
line 9 times and then sending the stop command.

This patch has been tested on a DM6446 and DM355

Signed-off-by: Philby John <pjohn@in.mvista.com>
Signed-off-by: Srinivasan, Nageswari <nageswari@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
---
 drivers/i2c/busses/i2c-davinci.c |   57 +++++++++++++++++++++++++++++++++++--
 1 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index fd7a155..0f71a7e 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -36,6 +36,7 @@
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/cpufreq.h>
+#include <linux/gpio.h>
 
 #include <mach/hardware.h>
 #include <mach/i2c.h>
@@ -43,6 +44,7 @@
 /* ----- global defines ----------------------------------------------- */
 
 #define DAVINCI_I2C_TIMEOUT	(1*HZ)
+#define DAVINCI_I2C_MAX_TRIES	2
 #define I2C_DAVINCI_INTR_ALL    (DAVINCI_I2C_IMR_AAS | \
 				 DAVINCI_I2C_IMR_SCD | \
 				 DAVINCI_I2C_IMR_ARDY | \
@@ -130,6 +132,44 @@ static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
 	return __raw_readw(i2c_dev->base + reg);
 }
 
+/* Generate a pulse on the i2c clock pin. */
+static void generic_i2c_clock_pulse(unsigned int scl_pin)
+{
+	u16 i;
+
+	if (scl_pin) {
+		/* Send high and low on the SCL line */
+		for (i = 0; i < 9; i++) {
+			gpio_set_value(scl_pin, 0);
+			udelay(20);
+			gpio_set_value(scl_pin, 1);
+			udelay(20);
+		}
+	}
+}
+
+/* This routine does i2c bus recovery as specified in the
+ * i2c protocol Rev. 03 section 3.16 titled "Bus clear"
+ */
+static void i2c_recover_bus(struct davinci_i2c_dev *dev)
+{
+	u32 flag = 0;
+	struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
+
+	dev_err(dev->dev, "initiating i2c bus recovery\n");
+	/* Send NACK to the slave */
+	flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
+	flag |=  DAVINCI_I2C_MDR_NACK;
+	/* write the data into mode register */
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
+	if (pdata)
+		generic_i2c_clock_pulse(pdata->scl_pin);
+	/* Send STOP */
+	flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
+	flag |= DAVINCI_I2C_MDR_STP;
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
+}
+
 static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
 								int val)
 {
@@ -235,14 +275,22 @@ static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
 					 char allow_sleep)
 {
 	unsigned long timeout;
+	static u16 to_cnt;
 
 	timeout = jiffies + dev->adapter.timeout;
 	while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
 	       & DAVINCI_I2C_STR_BB) {
-		if (time_after(jiffies, timeout)) {
-			dev_warn(dev->dev,
-				 "timeout waiting for bus ready\n");
-			return -ETIMEDOUT;
+		if (to_cnt <= DAVINCI_I2C_MAX_TRIES) {
+			if (time_after(jiffies, timeout)) {
+				dev_warn(dev->dev,
+				"timeout waiting for bus ready\n");
+				to_cnt++;
+				return -ETIMEDOUT;
+			} else {
+				to_cnt = 0;
+				i2c_recover_bus(dev);
+				i2c_davinci_init(dev);
+			}
 		}
 		if (allow_sleep)
 			schedule_timeout(1);
@@ -326,6 +374,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 						      dev->adapter.timeout);
 	if (r == 0) {
 		dev_err(dev->dev, "controller timed out\n");
+		i2c_recover_bus(dev);
 		i2c_davinci_init(dev);
 		dev->buf_len = 0;
 		return -ETIMEDOUT;
-- 
1.7.0.2