[PATCH v1] i2c: imx: Retry transfer on transient failure

[Marco Felsch]

Hi Francesco,

On 22-07-12, Francesco Dolcini wrote:
> From: Oleksandr Suvorov <oleksandr.suvorov at toradex.com>
> 
> Set the i2c_adapter retries field to a sensible value. This allows
> the i2c core to retry master_xfer()/master_xfer_atomic() when it
> returns -EAGAIN. Currently the i2c-imx driver returns -EAGAIN only
> on Tx arbitration failure (I2SR_IAL).
> 
> Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov at toradex.com>
> Signed-off-by: Francesco Dolcini <francesco.dolcini at toradex.com>
> ---
>  drivers/i2c/busses/i2c-imx.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index e9e2db68b9fb..26738e713c94 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -54,6 +54,7 @@
>  #define DRIVER_NAME "imx-i2c"
>  
>  #define I2C_IMX_CHECK_DELAY 30000 /* Time to check for bus idle, in NS */
> +#define I2C_IMX_MAX_RETRIES 3     /* Retries on arbitration loss */

Just one question: Why 3 and should we document this within the commit
message?

Regards,
  Marco

>  /*
>   * Enable DMA if transfer byte size is bigger than this threshold.
> @@ -1477,6 +1478,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
>  	i2c_imx->adapter.dev.parent	= &pdev->dev;
>  	i2c_imx->adapter.nr		= pdev->id;
>  	i2c_imx->adapter.dev.of_node	= pdev->dev.of_node;
> +	i2c_imx->adapter.retries	= I2C_IMX_MAX_RETRIES;
>  	i2c_imx->base			= base;
>  	ACPI_COMPANION_SET(&i2c_imx->adapter.dev, ACPI_COMPANION(&pdev->dev));
>  
> -- 
> 2.25.1
> 
> 
>