Re: pca953x: Probing too early

[Oleksij Rempel <o.rempel@pengutronix.de>]

Hi Fabio,

On Tue, Aug 20, 2024 at 09:50:04PM -0300, Fabio Estevam wrote:
> On Tue, Aug 20, 2024 at 8:18 PM Fabio Estevam <festevam@gmail.com> wrote:
> 
> > The pca953x driver tries to write to the i2c-2 bus before i2c-2 is registered.
> >
> > This is the point I don't understand: how can the pca953x driver get
> > probed before its I2C bus parent?
> 
> Disconsider what I wrote above.
> 
> I'm trying to recover from the arbitration lost like this:
> 
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -491,6 +491,8 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct
> *i2c_imx, int for_busy, bool a
>                 /* check for arbitration lost */
>                 if (temp & I2SR_IAL) {
>                         i2c_imx_clear_irq(i2c_imx, I2SR_IAL);
> +                       pr_err("******* Arbitration lost\n");
> +                       i2c_recover_bus(&i2c_imx->adapter);
>                         return -EAGAIN;
>                 }
> 
> @@ -1487,6 +1489,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
>         i2c_imx->adapter.nr             = pdev->id;
>         i2c_imx->adapter.dev.of_node    = pdev->dev.of_node;
>         i2c_imx->base                   = base;
> +       i2c_imx->adapter.retries        = 5;
>         ACPI_COMPANION_SET(&i2c_imx->adapter.dev, ACPI_COMPANION(&pdev->dev));
> 
> but still get pca953x probe failure:
> 
> [    1.756761] pca953x 2-0020: supply vcc not found, using dummy regulator
> [    1.766564] pca953x 2-0020: using no AI
> [    1.775333] ******* Arbitration lost
> [    1.783811] ******* Arbitration lost
> [    1.793701] ******* Arbitration lost
> [    1.797455] ******* Arbitration lost
> [    1.801209] ******* Arbitration lost
> [    1.804964] ******* Arbitration lost
> [    1.808562] pca953x 2-0020: failed writing register
> [    1.813602] pca953x: probe of 2-0020 failed with error -11
> [    1.819222] i2c i2c-2: IMX I2C adapter registered

Do you have a multi master i2c bus? If not, can you please test
following patch:
https://lore.kernel.org/all/20240715151824.90033-2-eichest@gmail.com/

Regards,
Oleksij
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