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

Marco Felsch
2022-07-12T08:47:27Z

Hi Francesco,

On 22-07-12, Francesco Dolcini wrote:
> From: Oleksandr Suvorov <oleksandr.suvorov@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@toradex.com>
> Signed-off-by: Francesco Dolcini <francesco.dolcini@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
>
>
>