i2c/pca: handle timeout

i2c/pca: handle timeout

[Wolfram Sang]

So, here are my patches to handle the timeout better with the
PCA-algorithm and -drivers. They compile (for me ;)) and with the
platform-driver I can still access an eeprom & rtc.

Please review.

Regards,

   Wolfram

[PATCH 1/3] i2c/algo-pca: rework waiting for a free bus

[Wolfram Sang]

Waiting for a free bus now accepts the timeout value in jiffies and does
proper checking using time_before.

Signed-off-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 drivers/i2c/algos/i2c-algo-pca.c |   18 ++++++++++--------
 drivers/i2c/busses/i2c-pca-isa.c |    2 +-
 include/linux/i2c-pca-platform.h |    2 +-
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
index a8e51bd..59ee88a 100644
--- a/drivers/i2c/algos/i2c-algo-pca.c
+++ b/drivers/i2c/algos/i2c-algo-pca.c
@@ -22,6 +22,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/delay.h>
+#include <linux/jiffies.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/i2c.h>
@@ -186,14 +187,15 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
 	int numbytes = 0;
 	int state;
 	int ret;
-	int timeout = i2c_adap->timeout;
+	unsigned long timeout = jiffies + i2c_adap->timeout;
 
-	while ((state = pca_status(adap)) != 0xf8 && timeout--) {
-		msleep(10);
-	}
-	if (state != 0xf8) {
-		dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state);
-		return -EAGAIN;
+	while (pca_status(adap) != 0xf8) {
+		if (time_before(jiffies, timeout)) {
+			msleep(10);
+		} else {
+			dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state);
+			return -EAGAIN;
+		}
 	}
 
 	DEB1("{{{ XFER %d messages\n", num);
diff --git a/drivers/i2c/busses/i2c-pca-isa.c b/drivers/i2c/busses/i2c-pca-isa.c
index 8835de2..84d035c 100644
--- a/drivers/i2c/busses/i2c-pca-isa.c
+++ b/drivers/i2c/busses/i2c-pca-isa.c
@@ -103,7 +103,7 @@ static struct i2c_adapter pca_isa_ops = {
 	.owner          = THIS_MODULE,
 	.algo_data	= &pca_isa_data,
 	.name		= "PCA9564/PCA9665 ISA Adapter",
-	.timeout	= 100,
+	.timeout	= HZ,
 };
 
 static int __devinit pca_isa_match(struct device *dev, unsigned int id)
diff --git a/include/linux/i2c-pca-platform.h b/include/linux/i2c-pca-platform.h
index 3d19187..aba3375 100644
--- a/include/linux/i2c-pca-platform.h
+++ b/include/linux/i2c-pca-platform.h
@@ -6,7 +6,7 @@ struct i2c_pca9564_pf_platform_data {
 				 * not supplied (negative value), but it
 				 * cannot exit some error conditions then */
 	int i2c_clock_speed;	/* values are defined in linux/i2c-algo-pca.h */
-	int timeout;		/* timeout = this value * 10us */
+	int timeout;		/* timeout in jiffies */
 };
 
 #endif /* I2C_PCA9564_PLATFORM_H */
-- 
1.5.6.5

Re: [PATCH 1/3] i2c/algo-pca: rework waiting for a free bus

[Jean Delvare]

Hi Wolfram,

On Tue, 24 Feb 2009 17:22:14 +0100, Wolfram Sang wrote:
> Waiting for a free bus now accepts the timeout value in jiffies and does
> proper checking using time_before.
> 
> Signed-off-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> ---
>  drivers/i2c/algos/i2c-algo-pca.c |   18 ++++++++++--------
>  drivers/i2c/busses/i2c-pca-isa.c |    2 +-
>  include/linux/i2c-pca-platform.h |    2 +-
>  3 files changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
> index a8e51bd..59ee88a 100644
> --- a/drivers/i2c/algos/i2c-algo-pca.c
> +++ b/drivers/i2c/algos/i2c-algo-pca.c
> @@ -22,6 +22,7 @@
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
>  #include <linux/delay.h>
> +#include <linux/jiffies.h>
>  #include <linux/init.h>
>  #include <linux/errno.h>
>  #include <linux/i2c.h>
> @@ -186,14 +187,15 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
>  	int numbytes = 0;
>  	int state;
>  	int ret;
> -	int timeout = i2c_adap->timeout;
> +	unsigned long timeout = jiffies + i2c_adap->timeout;
>  
> -	while ((state = pca_status(adap)) != 0xf8 && timeout--) {
> -		msleep(10);
> -	}
> -	if (state != 0xf8) {
> -		dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state);
> -		return -EAGAIN;
> +	while (pca_status(adap) != 0xf8) {
> +		if (time_before(jiffies, timeout)) {
> +			msleep(10);
> +		} else {
> +			dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state);

Line too long, needs folding.

> +			return -EAGAIN;
> +		}
>  	}
>  
>  	DEB1("{{{ XFER %d messages\n", num);
> diff --git a/drivers/i2c/busses/i2c-pca-isa.c b/drivers/i2c/busses/i2c-pca-isa.c
> index 8835de2..84d035c 100644
> --- a/drivers/i2c/busses/i2c-pca-isa.c
> +++ b/drivers/i2c/busses/i2c-pca-isa.c
> @@ -103,7 +103,7 @@ static struct i2c_adapter pca_isa_ops = {
>  	.owner          = THIS_MODULE,
>  	.algo_data	= &pca_isa_data,
>  	.name		= "PCA9564/PCA9665 ISA Adapter",
> -	.timeout	= 100,
> +	.timeout	= HZ,
>  };
>  
>  static int __devinit pca_isa_match(struct device *dev, unsigned int id)
> diff --git a/include/linux/i2c-pca-platform.h b/include/linux/i2c-pca-platform.h
> index 3d19187..aba3375 100644
> --- a/include/linux/i2c-pca-platform.h
> +++ b/include/linux/i2c-pca-platform.h
> @@ -6,7 +6,7 @@ struct i2c_pca9564_pf_platform_data {
>  				 * not supplied (negative value), but it
>  				 * cannot exit some error conditions then */
>  	int i2c_clock_speed;	/* values are defined in linux/i2c-algo-pca.h */
> -	int timeout;		/* timeout = this value * 10us */
> +	int timeout;		/* timeout in jiffies */

As you change the unit here, you need to update all instances of this
structure in the kernel tree. Which as far as I can see is really only
one in arch/sh/boards/board-sh7785lcr.c.

>  };
>  
>  #endif /* I2C_PCA9564_PLATFORM_H */


-- 
Jean Delvare

[PATCH V2 1/3] i2c/algo-pca: rework waiting for a free bus

[Wolfram Sang]

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Waiting for a free bus now accepts the timeout value in jiffies and does
proper checking using time_before.

Signed-off-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---

changes since V1:

* fix user sh7785lcr
* break >80 chars

 arch/sh/boards/board-sh7785lcr.c |    2 +-
 drivers/i2c/algos/i2c-algo-pca.c |   19 +++++++++++--------
 drivers/i2c/busses/i2c-pca-isa.c |    2 +-
 include/linux/i2c-pca-platform.h |    2 +-
 4 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/arch/sh/boards/board-sh7785lcr.c b/arch/sh/boards/board-sh7785lcr.c
index 38a6496..6258c79 100644
--- a/arch/sh/boards/board-sh7785lcr.c
+++ b/arch/sh/boards/board-sh7785lcr.c
@@ -229,7 +229,7 @@ static struct resource i2c_resources[] = {
 static struct i2c_pca9564_pf_platform_data i2c_platform_data = {
 	.gpio			= 0,
 	.i2c_clock_speed	= I2C_PCA_CON_330kHz,
-	.timeout		= 100,
+	.timeout		= HZ,
 };
 
 static struct platform_device i2c_device = {
diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
index a8e51bd..9e134fa 100644
--- a/drivers/i2c/algos/i2c-algo-pca.c
+++ b/drivers/i2c/algos/i2c-algo-pca.c
@@ -22,6 +22,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/delay.h>
+#include <linux/jiffies.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/i2c.h>
@@ -186,14 +187,16 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
 	int numbytes = 0;
 	int state;
 	int ret;
-	int timeout = i2c_adap->timeout;
+	unsigned long timeout = jiffies + i2c_adap->timeout;
 
-	while ((state = pca_status(adap)) != 0xf8 && timeout--) {
-		msleep(10);
-	}
-	if (state != 0xf8) {
-		dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state);
-		return -EAGAIN;
+	while (pca_status(adap) != 0xf8) {
+		if (time_before(jiffies, timeout)) {
+			msleep(10);
+		} else {
+			dev_dbg(&i2c_adap->dev, "bus is not idle. status is "
+				"%#04x\n", state);
+			return -EAGAIN;
+		}
 	}
 
 	DEB1("{{{ XFER %d messages\n", num);
diff --git a/drivers/i2c/busses/i2c-pca-isa.c b/drivers/i2c/busses/i2c-pca-isa.c
index 8835de2..84d035c 100644
--- a/drivers/i2c/busses/i2c-pca-isa.c
+++ b/drivers/i2c/busses/i2c-pca-isa.c
@@ -103,7 +103,7 @@ static struct i2c_adapter pca_isa_ops = {
 	.owner          = THIS_MODULE,
 	.algo_data	= &pca_isa_data,
 	.name		= "PCA9564/PCA9665 ISA Adapter",
-	.timeout	= 100,
+	.timeout	= HZ,
 };
 
 static int __devinit pca_isa_match(struct device *dev, unsigned int id)
diff --git a/include/linux/i2c-pca-platform.h b/include/linux/i2c-pca-platform.h
index 3d19187..aba3375 100644
--- a/include/linux/i2c-pca-platform.h
+++ b/include/linux/i2c-pca-platform.h
@@ -6,7 +6,7 @@ struct i2c_pca9564_pf_platform_data {
 				 * not supplied (negative value), but it
 				 * cannot exit some error conditions then */
 	int i2c_clock_speed;	/* values are defined in linux/i2c-algo-pca.h */
-	int timeout;		/* timeout = this value * 10us */
+	int timeout;		/* timeout in jiffies */
 };
 
 #endif /* I2C_PCA9564_PLATFORM_H */

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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Re: [PATCH V2 1/3] i2c/algo-pca: rework waiting for a free bus

[Jean Delvare]

On Fri, 27 Feb 2009 09:44:12 +0100, Wolfram Sang wrote:
> 
> Waiting for a free bus now accepts the timeout value in jiffies and does
> proper checking using time_before.
> 
> Signed-off-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> ---
> 
> changes since V1:
> 
> * fix user sh7785lcr
> * break >80 chars
> 
>  arch/sh/boards/board-sh7785lcr.c |    2 +-
>  drivers/i2c/algos/i2c-algo-pca.c |   19 +++++++++++--------
>  drivers/i2c/busses/i2c-pca-isa.c |    2 +-
>  include/linux/i2c-pca-platform.h |    2 +-
>  4 files changed, 14 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/sh/boards/board-sh7785lcr.c b/arch/sh/boards/board-sh7785lcr.c
> index 38a6496..6258c79 100644
> --- a/arch/sh/boards/board-sh7785lcr.c
> +++ b/arch/sh/boards/board-sh7785lcr.c
> @@ -229,7 +229,7 @@ static struct resource i2c_resources[] = {
>  static struct i2c_pca9564_pf_platform_data i2c_platform_data = {
>  	.gpio			= 0,
>  	.i2c_clock_speed	= I2C_PCA_CON_330kHz,
> -	.timeout		= 100,
> +	.timeout		= HZ,
>  };
>  
>  static struct platform_device i2c_device = {
> diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
> index a8e51bd..9e134fa 100644
> --- a/drivers/i2c/algos/i2c-algo-pca.c
> +++ b/drivers/i2c/algos/i2c-algo-pca.c
> @@ -22,6 +22,7 @@
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
>  #include <linux/delay.h>
> +#include <linux/jiffies.h>
>  #include <linux/init.h>
>  #include <linux/errno.h>
>  #include <linux/i2c.h>
> @@ -186,14 +187,16 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
>  	int numbytes = 0;
>  	int state;
>  	int ret;
> -	int timeout = i2c_adap->timeout;
> +	unsigned long timeout = jiffies + i2c_adap->timeout;
>  
> -	while ((state = pca_status(adap)) != 0xf8 && timeout--) {
> -		msleep(10);
> -	}
> -	if (state != 0xf8) {
> -		dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state);
> -		return -EAGAIN;
> +	while (pca_status(adap) != 0xf8) {
> +		if (time_before(jiffies, timeout)) {
> +			msleep(10);
> +		} else {
> +			dev_dbg(&i2c_adap->dev, "bus is not idle. status is "
> +				"%#04x\n", state);
> +			return -EAGAIN;
> +		}
>  	}
>  
>  	DEB1("{{{ XFER %d messages\n", num);
> diff --git a/drivers/i2c/busses/i2c-pca-isa.c b/drivers/i2c/busses/i2c-pca-isa.c
> index 8835de2..84d035c 100644
> --- a/drivers/i2c/busses/i2c-pca-isa.c
> +++ b/drivers/i2c/busses/i2c-pca-isa.c
> @@ -103,7 +103,7 @@ static struct i2c_adapter pca_isa_ops = {
>  	.owner          = THIS_MODULE,
>  	.algo_data	= &pca_isa_data,
>  	.name		= "PCA9564/PCA9665 ISA Adapter",
> -	.timeout	= 100,
> +	.timeout	= HZ,
>  };
>  
>  static int __devinit pca_isa_match(struct device *dev, unsigned int id)
> diff --git a/include/linux/i2c-pca-platform.h b/include/linux/i2c-pca-platform.h
> index 3d19187..aba3375 100644
> --- a/include/linux/i2c-pca-platform.h
> +++ b/include/linux/i2c-pca-platform.h
> @@ -6,7 +6,7 @@ struct i2c_pca9564_pf_platform_data {
>  				 * not supplied (negative value), but it
>  				 * cannot exit some error conditions then */
>  	int i2c_clock_speed;	/* values are defined in linux/i2c-algo-pca.h */
> -	int timeout;		/* timeout = this value * 10us */
> +	int timeout;		/* timeout in jiffies */
>  };
>  
>  #endif /* I2C_PCA9564_PLATFORM_H */
> 

Applied, thanks.

-- 
Jean Delvare

[PATCH 2/3] i2c/algo-pca: use timeout for checking the state machine

[Wolfram Sang]

We now timeout also if the state machine does not change within the
given time. For that, the driver-specific completion-functions are
extended to return true or false depending on the timeout. This then
gets checked in the algorithm.

Signed-off-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 drivers/i2c/algos/i2c-algo-pca.c      |   39 +++++++++++++++++---------------
 drivers/i2c/busses/i2c-pca-isa.c      |   18 +++++++++++----
 drivers/i2c/busses/i2c-pca-platform.c |   20 ++++++++--------
 3 files changed, 44 insertions(+), 33 deletions(-)

diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
index 59ee88a..4153aff 100644
--- a/drivers/i2c/algos/i2c-algo-pca.c
+++ b/drivers/i2c/algos/i2c-algo-pca.c
@@ -60,14 +60,14 @@ static void pca9665_reset(void *pd)
  *
  * returns after the start condition has occurred
  */
-static void pca_start(struct i2c_algo_pca_data *adap)
+static int pca_start(struct i2c_algo_pca_data *adap)
 {
 	int sta = pca_get_con(adap);
 	DEB2("=== START\n");
 	sta |= I2C_PCA_CON_STA;
 	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
 	pca_set_con(adap, sta);
-	pca_wait(adap);
+	return pca_wait(adap);
 }
 
 /*
@@ -75,14 +75,14 @@ static void pca_start(struct i2c_algo_pca_data *adap)
  *
  * return after the repeated start condition has occurred
  */
-static void pca_repeated_start(struct i2c_algo_pca_data *adap)
+static int pca_repeated_start(struct i2c_algo_pca_data *adap)
 {
 	int sta = pca_get_con(adap);
 	DEB2("=== REPEATED START\n");
 	sta |= I2C_PCA_CON_STA;
 	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
 	pca_set_con(adap, sta);
-	pca_wait(adap);
+	return pca_wait(adap);
 }
 
 /*
@@ -108,7 +108,7 @@ static void pca_stop(struct i2c_algo_pca_data *adap)
  *
  * returns after the address has been sent
  */
-static void pca_address(struct i2c_algo_pca_data *adap,
+static int pca_address(struct i2c_algo_pca_data *adap,
 			struct i2c_msg *msg)
 {
 	int sta = pca_get_con(adap);
@@ -125,7 +125,7 @@ static void pca_address(struct i2c_algo_pca_data *adap,
 	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
 	pca_set_con(adap, sta);
 
-	pca_wait(adap);
+	return pca_wait(adap);
 }
 
 /*
@@ -133,7 +133,7 @@ static void pca_address(struct i2c_algo_pca_data *adap,
  *
  * Returns after the byte has been transmitted
  */
-static void pca_tx_byte(struct i2c_algo_pca_data *adap,
+static int pca_tx_byte(struct i2c_algo_pca_data *adap,
 			__u8 b)
 {
 	int sta = pca_get_con(adap);
@@ -143,7 +143,7 @@ static void pca_tx_byte(struct i2c_algo_pca_data *adap,
 	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
 	pca_set_con(adap, sta);
 
-	pca_wait(adap);
+	return pca_wait(adap);
 }
 
 /*
@@ -163,7 +163,7 @@ static void pca_rx_byte(struct i2c_algo_pca_data *adap,
  *
  * Returns after next byte has arrived.
  */
-static void pca_rx_ack(struct i2c_algo_pca_data *adap,
+static int pca_rx_ack(struct i2c_algo_pca_data *adap,
 		       int ack)
 {
 	int sta = pca_get_con(adap);
@@ -174,7 +174,7 @@ static void pca_rx_ack(struct i2c_algo_pca_data *adap,
 		sta |= I2C_PCA_CON_AA;
 
 	pca_set_con(adap, sta);
-	pca_wait(adap);
+	return pca_wait(adap);
 }
 
 static int pca_xfer(struct i2c_adapter *i2c_adap,
@@ -187,6 +187,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
 	int numbytes = 0;
 	int state;
 	int ret;
+	int completed = 1;
 	unsigned long timeout = jiffies + i2c_adap->timeout;
 
 	while (pca_status(adap) != 0xf8) {
@@ -231,18 +232,18 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
 
 		switch (state) {
 		case 0xf8: /* On reset or stop the bus is idle */
-			pca_start(adap);
+			completed = pca_start(adap);
 			break;
 
 		case 0x08: /* A START condition has been transmitted */
 		case 0x10: /* A repeated start condition has been transmitted */
-			pca_address(adap, msg);
+			completed = pca_address(adap, msg);
 			break;
 
 		case 0x18: /* SLA+W has been transmitted; ACK has been received */
 		case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
 			if (numbytes < msg->len) {
-				pca_tx_byte(adap, msg->buf[numbytes]);
+				completed = pca_tx_byte(adap, msg->buf[numbytes]);
 				numbytes++;
 				break;
 			}
@@ -250,7 +251,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
 			if (curmsg == num)
 				pca_stop(adap);
 			else
-				pca_repeated_start(adap);
+				completed = pca_repeated_start(adap);
 			break;
 
 		case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
@@ -259,21 +260,21 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
 			goto out;
 
 		case 0x40: /* SLA+R has been transmitted; ACK has been received */
-			pca_rx_ack(adap, msg->len > 1);
+			completed = pca_rx_ack(adap, msg->len > 1);
 			break;
 
 		case 0x50: /* Data bytes has been received; ACK has been returned */
 			if (numbytes < msg->len) {
 				pca_rx_byte(adap, &msg->buf[numbytes], 1);
 				numbytes++;
-				pca_rx_ack(adap, numbytes < msg->len - 1);
+				completed = pca_rx_ack(adap, numbytes < msg->len - 1);
 				break;
 			}
 			curmsg++; numbytes = 0;
 			if (curmsg == num)
 				pca_stop(adap);
 			else
-				pca_repeated_start(adap);
+				completed = pca_repeated_start(adap);
 			break;
 
 		case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
@@ -296,7 +297,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
 				if (curmsg == num)
 					pca_stop(adap);
 				else
-					pca_repeated_start(adap);
+					completed = pca_repeated_start(adap);
 			} else {
 				DEB2("NOT ACK sent after data byte received. "
 				     "Not final byte. numbytes %d. len %d\n",
@@ -322,6 +323,8 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
 			break;
 		}
 
+		if (!completed)
+			goto out;
 	}
 
 	ret = curmsg;
diff --git a/drivers/i2c/busses/i2c-pca-isa.c b/drivers/i2c/busses/i2c-pca-isa.c
index 84d035c..a523be8 100644
--- a/drivers/i2c/busses/i2c-pca-isa.c
+++ b/drivers/i2c/busses/i2c-pca-isa.c
@@ -23,6 +23,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/delay.h>
+#include <linux/jiffies.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/wait.h>
@@ -43,6 +44,7 @@ static int irq = -1;
  * in the actual clock rate */
 static int clock  = 59000;
 
+static struct i2c_adapter pca_isa_ops;
 static wait_queue_head_t pca_wait;
 
 static void pca_isa_writebyte(void *pd, int reg, int val)
@@ -68,16 +70,22 @@ static int pca_isa_readbyte(void *pd, int reg)
 
 static int pca_isa_waitforcompletion(void *pd)
 {
-	int ret = 0;
+	long ret = ~0;
+	unsigned long timeout;
 
 	if (irq > -1) {
-		ret = wait_event_interruptible(pca_wait,
-					       pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI);
+		ret = wait_event_interruptible_timeout(pca_wait,
+				pca_isa_readbyte(pd, I2C_PCA_CON)
+				& I2C_PCA_CON_SI, pca_isa_ops.timeout);
 	} else {
-		while ((pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
+		/* Do polling */
+		timeout = jiffies + pca_isa_ops.timeout;
+		while (((pca_isa_readbyte(pd, I2C_PCA_CON)
+				& I2C_PCA_CON_SI) == 0)
+				&& (ret = time_before(jiffies, timeout)))
 			udelay(100);
 	}
-	return ret;
+	return ret > 0;
 }
 
 static void pca_isa_resetchip(void *pd)
diff --git a/drivers/i2c/busses/i2c-pca-platform.c b/drivers/i2c/busses/i2c-pca-platform.c
index 51d179b..df5e593 100644
--- a/drivers/i2c/busses/i2c-pca-platform.c
+++ b/drivers/i2c/busses/i2c-pca-platform.c
@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
+#include <linux/jiffies.h>
 #include <linux/errno.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
@@ -81,24 +82,23 @@ static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
 static int i2c_pca_pf_waitforcompletion(void *pd)
 {
 	struct i2c_pca_pf_data *i2c = pd;
-	int ret = 0;
+	long ret = ~0;
+	unsigned long timeout;
 
 	if (i2c->irq) {
-		ret = wait_event_interruptible(i2c->wait,
+		ret = wait_event_interruptible_timeout(i2c->wait,
 			i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
-			& I2C_PCA_CON_SI);
+			& I2C_PCA_CON_SI, i2c->adap.timeout);
 	} else {
-		/*
-		 * Do polling...
-		 * XXX: Could get stuck in extreme cases!
-		 *      Maybe add timeout, but using irqs is preferred anyhow.
-		 */
-		while ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
+		/* Do polling */
+		timeout = jiffies + i2c->adap.timeout;
+		while (((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
 				& I2C_PCA_CON_SI) == 0)
+				&& (ret = time_before(jiffies, timeout)))
 			udelay(100);
 	}
 
-	return ret;
+	return ret > 0;
 }
 
 static void i2c_pca_pf_dummyreset(void *pd)
-- 
1.5.6.5

Re: [PATCH 2/3] i2c/algo-pca: use timeout for checking the state machine

[Jean Delvare]

On Tue, 24 Feb 2009 17:22:15 +0100, Wolfram Sang wrote:
> We now timeout also if the state machine does not change within the
> given time. For that, the driver-specific completion-functions are
> extended to return true or false depending on the timeout. This then
> gets checked in the algorithm.
> 
> Signed-off-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> ---
>  drivers/i2c/algos/i2c-algo-pca.c      |   39 +++++++++++++++++---------------
>  drivers/i2c/busses/i2c-pca-isa.c      |   18 +++++++++++----
>  drivers/i2c/busses/i2c-pca-platform.c |   20 ++++++++--------
>  3 files changed, 44 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
> index 59ee88a..4153aff 100644
> --- a/drivers/i2c/algos/i2c-algo-pca.c
> +++ b/drivers/i2c/algos/i2c-algo-pca.c
> @@ -60,14 +60,14 @@ static void pca9665_reset(void *pd)
>   *
>   * returns after the start condition has occurred
>   */
> -static void pca_start(struct i2c_algo_pca_data *adap)
> +static int pca_start(struct i2c_algo_pca_data *adap)
>  {
>  	int sta = pca_get_con(adap);
>  	DEB2("=== START\n");
>  	sta |= I2C_PCA_CON_STA;
>  	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
>  	pca_set_con(adap, sta);
> -	pca_wait(adap);
> +	return pca_wait(adap);
>  }
>  
>  /*
> @@ -75,14 +75,14 @@ static void pca_start(struct i2c_algo_pca_data *adap)
>   *
>   * return after the repeated start condition has occurred
>   */
> -static void pca_repeated_start(struct i2c_algo_pca_data *adap)
> +static int pca_repeated_start(struct i2c_algo_pca_data *adap)
>  {
>  	int sta = pca_get_con(adap);
>  	DEB2("=== REPEATED START\n");
>  	sta |= I2C_PCA_CON_STA;
>  	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
>  	pca_set_con(adap, sta);
> -	pca_wait(adap);
> +	return pca_wait(adap);
>  }
>  
>  /*
> @@ -108,7 +108,7 @@ static void pca_stop(struct i2c_algo_pca_data *adap)
>   *
>   * returns after the address has been sent
>   */
> -static void pca_address(struct i2c_algo_pca_data *adap,
> +static int pca_address(struct i2c_algo_pca_data *adap,
>  			struct i2c_msg *msg)
>  {
>  	int sta = pca_get_con(adap);
> @@ -125,7 +125,7 @@ static void pca_address(struct i2c_algo_pca_data *adap,
>  	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
>  	pca_set_con(adap, sta);
>  
> -	pca_wait(adap);
> +	return pca_wait(adap);
>  }
>  
>  /*
> @@ -133,7 +133,7 @@ static void pca_address(struct i2c_algo_pca_data *adap,
>   *
>   * Returns after the byte has been transmitted
>   */
> -static void pca_tx_byte(struct i2c_algo_pca_data *adap,
> +static int pca_tx_byte(struct i2c_algo_pca_data *adap,
>  			__u8 b)
>  {
>  	int sta = pca_get_con(adap);
> @@ -143,7 +143,7 @@ static void pca_tx_byte(struct i2c_algo_pca_data *adap,
>  	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
>  	pca_set_con(adap, sta);
>  
> -	pca_wait(adap);
> +	return pca_wait(adap);
>  }
>  
>  /*
> @@ -163,7 +163,7 @@ static void pca_rx_byte(struct i2c_algo_pca_data *adap,
>   *
>   * Returns after next byte has arrived.
>   */
> -static void pca_rx_ack(struct i2c_algo_pca_data *adap,
> +static int pca_rx_ack(struct i2c_algo_pca_data *adap,
>  		       int ack)
>  {
>  	int sta = pca_get_con(adap);
> @@ -174,7 +174,7 @@ static void pca_rx_ack(struct i2c_algo_pca_data *adap,
>  		sta |= I2C_PCA_CON_AA;
>  
>  	pca_set_con(adap, sta);
> -	pca_wait(adap);
> +	return pca_wait(adap);
>  }
>  
>  static int pca_xfer(struct i2c_adapter *i2c_adap,
> @@ -187,6 +187,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
>  	int numbytes = 0;
>  	int state;
>  	int ret;
> +	int completed = 1;
>  	unsigned long timeout = jiffies + i2c_adap->timeout;
>  
>  	while (pca_status(adap) != 0xf8) {
> @@ -231,18 +232,18 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
>  
>  		switch (state) {
>  		case 0xf8: /* On reset or stop the bus is idle */
> -			pca_start(adap);
> +			completed = pca_start(adap);
>  			break;
>  
>  		case 0x08: /* A START condition has been transmitted */
>  		case 0x10: /* A repeated start condition has been transmitted */
> -			pca_address(adap, msg);
> +			completed = pca_address(adap, msg);
>  			break;
>  
>  		case 0x18: /* SLA+W has been transmitted; ACK has been received */
>  		case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
>  			if (numbytes < msg->len) {
> -				pca_tx_byte(adap, msg->buf[numbytes]);
> +				completed = pca_tx_byte(adap, msg->buf[numbytes]);
>  				numbytes++;
>  				break;
>  			}
> @@ -250,7 +251,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
>  			if (curmsg == num)
>  				pca_stop(adap);
>  			else
> -				pca_repeated_start(adap);
> +				completed = pca_repeated_start(adap);
>  			break;
>  
>  		case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
> @@ -259,21 +260,21 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
>  			goto out;
>  
>  		case 0x40: /* SLA+R has been transmitted; ACK has been received */
> -			pca_rx_ack(adap, msg->len > 1);
> +			completed = pca_rx_ack(adap, msg->len > 1);
>  			break;
>  
>  		case 0x50: /* Data bytes has been received; ACK has been returned */
>  			if (numbytes < msg->len) {
>  				pca_rx_byte(adap, &msg->buf[numbytes], 1);
>  				numbytes++;
> -				pca_rx_ack(adap, numbytes < msg->len - 1);
> +				completed = pca_rx_ack(adap, numbytes < msg->len - 1);
>  				break;
>  			}
>  			curmsg++; numbytes = 0;
>  			if (curmsg == num)
>  				pca_stop(adap);
>  			else
> -				pca_repeated_start(adap);
> +				completed = pca_repeated_start(adap);
>  			break;
>  
>  		case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
> @@ -296,7 +297,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
>  				if (curmsg == num)
>  					pca_stop(adap);
>  				else
> -					pca_repeated_start(adap);
> +					completed = pca_repeated_start(adap);
>  			} else {
>  				DEB2("NOT ACK sent after data byte received. "
>  				     "Not final byte. numbytes %d. len %d\n",
> @@ -322,6 +323,8 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
>  			break;
>  		}
>  
> +		if (!completed)
> +			goto out;
>  	}
>  
>  	ret = curmsg;
> diff --git a/drivers/i2c/busses/i2c-pca-isa.c b/drivers/i2c/busses/i2c-pca-isa.c
> index 84d035c..a523be8 100644
> --- a/drivers/i2c/busses/i2c-pca-isa.c
> +++ b/drivers/i2c/busses/i2c-pca-isa.c
> @@ -23,6 +23,7 @@
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
>  #include <linux/delay.h>
> +#include <linux/jiffies.h>
>  #include <linux/init.h>
>  #include <linux/interrupt.h>
>  #include <linux/wait.h>
> @@ -43,6 +44,7 @@ static int irq = -1;
>   * in the actual clock rate */
>  static int clock  = 59000;
>  
> +static struct i2c_adapter pca_isa_ops;
>  static wait_queue_head_t pca_wait;
>  
>  static void pca_isa_writebyte(void *pd, int reg, int val)
> @@ -68,16 +70,22 @@ static int pca_isa_readbyte(void *pd, int reg)
>  
>  static int pca_isa_waitforcompletion(void *pd)
>  {
> -	int ret = 0;
> +	long ret = ~0;
> +	unsigned long timeout;
>  
>  	if (irq > -1) {
> -		ret = wait_event_interruptible(pca_wait,
> -					       pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI);
> +		ret = wait_event_interruptible_timeout(pca_wait,
> +				pca_isa_readbyte(pd, I2C_PCA_CON)
> +				& I2C_PCA_CON_SI, pca_isa_ops.timeout);
>  	} else {
> -		while ((pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
> +		/* Do polling */
> +		timeout = jiffies + pca_isa_ops.timeout;
> +		while (((pca_isa_readbyte(pd, I2C_PCA_CON)
> +				& I2C_PCA_CON_SI) == 0)
> +				&& (ret = time_before(jiffies, timeout)))
>  			udelay(100);
>  	}
> -	return ret;
> +	return ret > 0;
>  }
>  
>  static void pca_isa_resetchip(void *pd)
> diff --git a/drivers/i2c/busses/i2c-pca-platform.c b/drivers/i2c/busses/i2c-pca-platform.c
> index 51d179b..df5e593 100644
> --- a/drivers/i2c/busses/i2c-pca-platform.c
> +++ b/drivers/i2c/busses/i2c-pca-platform.c
> @@ -15,6 +15,7 @@
>  #include <linux/init.h>
>  #include <linux/slab.h>
>  #include <linux/delay.h>
> +#include <linux/jiffies.h>
>  #include <linux/errno.h>
>  #include <linux/i2c.h>
>  #include <linux/interrupt.h>
> @@ -81,24 +82,23 @@ static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
>  static int i2c_pca_pf_waitforcompletion(void *pd)
>  {
>  	struct i2c_pca_pf_data *i2c = pd;
> -	int ret = 0;
> +	long ret = ~0;
> +	unsigned long timeout;
>  
>  	if (i2c->irq) {
> -		ret = wait_event_interruptible(i2c->wait,
> +		ret = wait_event_interruptible_timeout(i2c->wait,
>  			i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
> -			& I2C_PCA_CON_SI);
> +			& I2C_PCA_CON_SI, i2c->adap.timeout);
>  	} else {
> -		/*
> -		 * Do polling...
> -		 * XXX: Could get stuck in extreme cases!
> -		 *      Maybe add timeout, but using irqs is preferred anyhow.
> -		 */
> -		while ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
> +		/* Do polling */
> +		timeout = jiffies + i2c->adap.timeout;
> +		while (((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
>  				& I2C_PCA_CON_SI) == 0)
> +				&& (ret = time_before(jiffies, timeout)))
>  			udelay(100);
>  	}
>  
> -	return ret;
> +	return ret > 0;
>  }
>  
>  static void i2c_pca_pf_dummyreset(void *pd)

Looks good. Applied, thanks.

-- 
Jean Delvare

[PATCH 3/3] i2c/pca-platform: use defaults if no platform_data given

[Wolfram Sang]

Signed-off-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 drivers/i2c/busses/i2c-pca-platform.c |   19 ++++++++++++-------
 1 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pca-platform.c b/drivers/i2c/busses/i2c-pca-platform.c
index df5e593..7b23891 100644
--- a/drivers/i2c/busses/i2c-pca-platform.c
+++ b/drivers/i2c/busses/i2c-pca-platform.c
@@ -177,10 +177,20 @@ static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
 		 (unsigned long) res->start);
 	i2c->adap.algo_data = &i2c->algo_data;
 	i2c->adap.dev.parent = &pdev->dev;
-	i2c->adap.timeout = platform_data->timeout;
 
-	i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
+	if (platform_data) {
+		i2c->adap.timeout = platform_data->timeout;
+		i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
+		i2c->gpio = platform_data->gpio;
+	} else {
+		i2c->adap.timeout = HZ;
+		i2c->algo_data.i2c_clock = 59000;
+		i2c->gpio = -1;
+	}
+
 	i2c->algo_data.data = i2c;
+	i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
+	i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;
 
 	switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
 	case IORESOURCE_MEM_32BIT:
@@ -198,11 +208,6 @@ static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
 		break;
 	}
 
-	i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
-
-	i2c->gpio = platform_data->gpio;
-	i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;
-
 	/* Use gpio_is_valid() when in mainline */
 	if (i2c->gpio > -1) {
 		ret = gpio_request(i2c->gpio, i2c->adap.name);
-- 
1.5.6.5

Re: [PATCH 3/3] i2c/pca-platform: use defaults if no platform_data given

[Jean Delvare]

On Tue, 24 Feb 2009 17:22:16 +0100, Wolfram Sang wrote:
> Signed-off-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> ---
>  drivers/i2c/busses/i2c-pca-platform.c |   19 ++++++++++++-------
>  1 files changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-pca-platform.c b/drivers/i2c/busses/i2c-pca-platform.c
> index df5e593..7b23891 100644
> --- a/drivers/i2c/busses/i2c-pca-platform.c
> +++ b/drivers/i2c/busses/i2c-pca-platform.c
> @@ -177,10 +177,20 @@ static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
>  		 (unsigned long) res->start);
>  	i2c->adap.algo_data = &i2c->algo_data;
>  	i2c->adap.dev.parent = &pdev->dev;
> -	i2c->adap.timeout = platform_data->timeout;
>  
> -	i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
> +	if (platform_data) {
> +		i2c->adap.timeout = platform_data->timeout;
> +		i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
> +		i2c->gpio = platform_data->gpio;
> +	} else {
> +		i2c->adap.timeout = HZ;
> +		i2c->algo_data.i2c_clock = 59000;
> +		i2c->gpio = -1;
> +	}
> +
>  	i2c->algo_data.data = i2c;
> +	i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
> +	i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;
>  
>  	switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
>  	case IORESOURCE_MEM_32BIT:
> @@ -198,11 +208,6 @@ static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
>  		break;
>  	}
>  
> -	i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
> -
> -	i2c->gpio = platform_data->gpio;
> -	i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;
> -
>  	/* Use gpio_is_valid() when in mainline */
>  	if (i2c->gpio > -1) {
>  		ret = gpio_request(i2c->gpio, i2c->adap.name);

Applied, thanks.

-- 
Jean Delvare