[PATCH] i2c: core: only use set_scl for bus recovery after calling prepare_recovery

[PATCH] i2c: core: only use set_scl for bus recovery after calling prepare_recovery

[Jan Luebbe]

Using set_scl may be ineffective before calling the driver specific
prepare_recovery callback, which might change into a test mode. So
instead of setting SCL in i2c_generic_scl_recovery, move it to
i2c_generic_recovery (after the optional prepare_recovery).

Signed-off-by: Jan Luebbe <jlu-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 drivers/i2c/i2c-core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 069a41f116dd..be992b3e0be8 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -567,6 +567,9 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
 	if (bri->prepare_recovery)
 		bri->prepare_recovery(adap);
 
+	bri->set_scl(adap, val);
+	ndelay(RECOVERY_NDELAY);
+
 	/*
 	 * By this time SCL is high, as we need to give 9 falling-rising edges
 	 */
@@ -597,7 +600,6 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
 
 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 {
-	adap->bus_recovery_info->set_scl(adap, 1);
 	return i2c_generic_recovery(adap);
 }
 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
-- 
2.1.4

Re: [PATCH] i2c: core: only use set_scl for bus recovery after calling prepare_recovery

[Alexander Sverdlin]

Hi!

On 08/07/15 16:35, ext Jan Luebbe wrote:
> Using set_scl may be ineffective before calling the driver specific
> prepare_recovery callback, which might change into a test mode. So
> instead of setting SCL in i2c_generic_scl_recovery, move it to
> i2c_generic_recovery (after the optional prepare_recovery).
> 
> Signed-off-by: Jan Luebbe <jlu@pengutronix.de>

Makes sense,
Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>

> ---
>  drivers/i2c/i2c-core.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 069a41f116dd..be992b3e0be8 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -567,6 +567,9 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
>  	if (bri->prepare_recovery)
>  		bri->prepare_recovery(adap);
>  
> +	bri->set_scl(adap, val);
> +	ndelay(RECOVERY_NDELAY);
> +
>  	/*
>  	 * By this time SCL is high, as we need to give 9 falling-rising edges
>  	 */
> @@ -597,7 +600,6 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
>  
>  int i2c_generic_scl_recovery(struct i2c_adapter *adap)
>  {
> -	adap->bus_recovery_info->set_scl(adap, 1);
>  	return i2c_generic_recovery(adap);
>  }
>  EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);

-- 
Best regards,
Alexander Sverdlin.

Re: [PATCH] i2c: core: only use set_scl for bus recovery after calling prepare_recovery

[Alexander Sverdlin]

On 08/07/15 16:35, Jan Luebbe wrote:
> Using set_scl may be ineffective before calling the driver specific
> prepare_recovery callback, which might change into a test mode. So
> instead of setting SCL in i2c_generic_scl_recovery, move it to
> i2c_generic_recovery (after the optional prepare_recovery).
> 
> Signed-off-by: Jan Luebbe <jlu-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>

I've tested it with oscilloscope on Beagle Bone Black, makes sense with
your next patch, so:

Tested-by: Alexander Sverdlin <alexander.sverdlin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

> ---
>  drivers/i2c/i2c-core.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 069a41f116dd..be992b3e0be8 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -567,6 +567,9 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
>  	if (bri->prepare_recovery)
>  		bri->prepare_recovery(adap);
>  
> +	bri->set_scl(adap, val);
> +	ndelay(RECOVERY_NDELAY);
> +
>  	/*
>  	 * By this time SCL is high, as we need to give 9 falling-rising edges
>  	 */
> @@ -597,7 +600,6 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
>  
>  int i2c_generic_scl_recovery(struct i2c_adapter *adap)
>  {
> -	adap->bus_recovery_info->set_scl(adap, 1);
>  	return i2c_generic_recovery(adap);
>  }
>  EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
> 

Re: [PATCH] i2c: core: only use set_scl for bus recovery after calling prepare_recovery

[Wolfram Sang]

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On Wed, Jul 08, 2015 at 04:35:06PM +0200, Jan Luebbe wrote:
> Using set_scl may be ineffective before calling the driver specific
> prepare_recovery callback, which might change into a test mode. So
> instead of setting SCL in i2c_generic_scl_recovery, move it to
> i2c_generic_recovery (after the optional prepare_recovery).
> 
> Signed-off-by: Jan Luebbe <jlu-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>

Applied to for-current, thanks!


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