Re: [PATCH v8 4/4] i2c: qcom-geni: Support multi-owner controllers in GPI mode

On 7/8/26 7:10 AM, Mukesh Kumar Savaliya wrote:
> Some platforms use a QUP-based I2C controller in a configuration where the
> controller is shared with another system processor. In this setup the
> operating system must not assume exclusive ownership of the controller or
> its associated pins.
> 
> Add support for enabling multi-owner operation when DeviceTree specifies
> qcom,qup-multi-owner. When enabled, mark the underlying serial engine as
> shared so the common GENI resource handling avoids selecting the "sleep"
> pinctrl state, which could disrupt transfers initiated by the other
> processor.
> 
> For GPI mode transfers, request lock/unlock TRE sequencing from the GPI
> driver by setting a single lock_action selector per message, emitting lock
> before the first message and unlock after the last message (handling the
> single-message case as well). This serializes access to the shared
> controller without requiring message-position flags to be passed into the
> DMA engine layer.
> 
> Signed-off-by: Mukesh Kumar Savaliya <[email protected]>
> ---

[...]


> +		if (gi2c->se.multi_owner)
> +			return dev_err_probe(gi2c->se.dev, -EINVAL,
> +					     "I2C sharing not supported in non GSI mode\n");

ultra nit: "non-GSI"

> +
>  		tx_depth = geni_se_get_tx_fifo_depth(&gi2c->se);
>  
>  		/* I2C Master Hub Serial Elements doesn't have the HW_PARAM_0 register */
> @@ -1098,6 +1115,11 @@ static int geni_i2c_probe(struct platform_device *pdev)
>  		gi2c->clk_freq_out = I2C_MAX_STANDARD_MODE_FREQ;
>  	}
>  
> +	if (of_property_read_bool(pdev->dev.of_node, "qcom,qup-multi-owner")) {

Let's use device_property_present() instead.

with that:

Reviewed-by: Konrad Dybcio <[email protected]>

Konrad