[PATCH] i2c-au1550: increase timeout waiting for transactions to finish

[PATCH] i2c-au1550: increase timeout waiting for transactions to finish

[Manuel Lauss]

Wait a bit longer for the I2C master transaction to finish.
With this change the WM8731 codec on the DB1300 board is now
reliably initialized.

Tested on Db1200 and Db1300.

Signed-off-by: Manuel Lauss <manuel.lauss-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
---
 drivers/i2c/busses/i2c-au1550.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/i2c/busses/i2c-au1550.c b/drivers/i2c/busses/i2c-au1550.c
index 532828b..e4ece23 100644
--- a/drivers/i2c/busses/i2c-au1550.c
+++ b/drivers/i2c/busses/i2c-au1550.c
@@ -106,7 +106,7 @@ wait_master_done(struct i2c_au1550_data *adap)
 		au_sync();
 		if ((stat & PSC_SMBEVNT_MD) != 0)
 			return 0;
-		udelay(1);
+		udelay(2);
 	}
 
 	return -ETIMEDOUT;
-- 
1.7.5.3

Re: [PATCH] i2c-au1550: increase timeout waiting for transactions to finish

[Ben Dooks]

On Sun, Jun 12, 2011 at 02:31:27PM +0200, Manuel Lauss wrote:
> Wait a bit longer for the I2C master transaction to finish.
> With this change the WM8731 codec on the DB1300 board is now
> reliably initialized.
> 
> Tested on Db1200 and Db1300.
> 
> Signed-off-by: Manuel Lauss <manuel.lauss-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>

If no-one else can think of a better fix, then this can go into -rc.

Is there no register that could be read to find out if the system is
busy?

> ---
>  drivers/i2c/busses/i2c-au1550.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-au1550.c b/drivers/i2c/busses/i2c-au1550.c
> index 532828b..e4ece23 100644
> --- a/drivers/i2c/busses/i2c-au1550.c
> +++ b/drivers/i2c/busses/i2c-au1550.c
> @@ -106,7 +106,7 @@ wait_master_done(struct i2c_au1550_data *adap)
>  		au_sync();
>  		if ((stat & PSC_SMBEVNT_MD) != 0)
>  			return 0;
> -		udelay(1);
> +		udelay(2);
>  	}
>  
>  	return -ETIMEDOUT;
> -- 
> 1.7.5.3
> 
> --
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-- 
Ben Dooks, ben-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, http://www.fluff.org/ben/

Large Hadron Colada: A large Pina Colada that makes the universe disappear.

Re: [PATCH] i2c-au1550: increase timeout waiting for transactions to finish

[Manuel Lauss]

On Wed, Jun 15, 2011 at 11:40 PM, Ben Dooks <ben-i2c-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org> wrote:
> On Sun, Jun 12, 2011 at 02:31:27PM +0200, Manuel Lauss wrote:
>> Wait a bit longer for the I2C master transaction to finish.
>> With this change the WM8731 codec on the DB1300 board is now
>> reliably initialized.
>>
>> Tested on Db1200 and Db1300.
>>
>> Signed-off-by: Manuel Lauss <manuel.lauss-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
>
> If no-one else can think of a better fix, then this can go into -rc.
>
> Is there no register that could be read to find out if the system is
> busy?

That's what the function in the patch does: polls for the "master done"
bit to be set.  The timeout around it is just too short for some systems.

Next merge window is fine for this too.  For the current in-tree users this
driver actually works fine.

Manuel Lauss