Re: [PATCH v6] i2c: i2c-qcom-geni: serve transfers during early resume

[Aniket RANDIVE <aniket.randive@oss.qualcomm.com>]

On 6/29/2026 7:11 PM, Mukesh Kumar Savaliya wrote:
> I2C transfers issued during the resume_noirq phase can fail on GENI I2C
> controllers.
> 
> Some devices require I2C communication before their resume sequence can
> complete. One example is a USB Ethernet device attached through PCIe,
> where device configuration must be restored over I2C before PCIe link
> initialization can proceed. Since such accesses occur during
> resume_noirq(), the underlying I2C controller must be able to service
> transfers at that stage.
> 
> However, GENI I2C transfers rely on interrupts for command completion,
> while IRQ handling is still suspended during early resume. Additionally,
> runtime PM may remain disabled until later in the resume sequence, causing
> pm_runtime_get_sync() to return -EACCES and preventing controller
> resources from being enabled.
> 
> Allow the controller to operate during early resume by requesting the IRQ
> with IRQF_NO_SUSPEND and IRQF_EARLY_RESUME so completion interrupts can be
> delivered during the noirq phase. Also restore runtime PM from
> resume_noirq() when it is disabled and tolerate transient -EACCES failures
> from pm_runtime_get_sync() during the PM state transition.
> 
> This enables GENI I2C transfers to complete successfully during the
> resume_noirq phase and allows dependent devices to finish their resume
> sequence.
> 
> Co-developed-by: Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>
> Signed-off-by: Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>
> Signed-off-by: Mukesh Kumar Savaliya <mukesh.savaliya@oss.qualcomm.com>
> ---
> v5->v6 :
> - Modified commit log to start with problem description as suggested by Bjorn.
> - Moved to new implementation of the logic while earlier replied to comments on
>    older design and considers latest fix added recently.
> - Made change generic to I2C including GPI mode transfer, this was not done earlier.
> - Changed email address to oss.qualcomm.com domain.
> Link to V5: https://lore.kernel.org/lkml/20241227130236.755794-1-quic_msavaliy@quicinc.com/
> 
> ---
> v4->v5:
> - Commit log enhanced considering Bjorn's comments by explaining PCIe usecase.
> - Enhanced comment with reason when using pm_runtime_force_resume().
> - Corrected IS_ENABLED(CONFIG_PM) condition inside geni_i2c_xfer().
> - Improved debug log as per Bjorn's suggestions during suspend, resume.
> - Reverted back comment before devm_request_irq().
> Link to V4: https://lore.kernel.org/lkml/bd699719-4958-445a-a685-4b5f6a8ad81f@quicinc.com/
> 
> ---
> v3->v4 :
>   - Enhanced commit log by explaining client usecase scenario during early resume.
>   - Covered 'usage_count' of 'struct dev_pm_info' under CONFIG_PM to compile non PM CONFIG.
> Link to V3: https://lore.kernel.org/all/20241119143031.3331753-1-quic_msavaliy@quicinc.com/T/
> 
> ---
> v2 -> v3:
>   - Updated exact usecase and scenario in the commit log description.
>   - Removed bulleted points from technical description, added details in free flow.
>   - Used pm_runtime_force_resume/suspend() instead customized local implementation.
>   - Added debug log after pm_runtime_force_suspend().
> Link to V2: https://lore.kernel.org/lkml/202410132233.P25W2vKq-lkp@intel.com/T/
> 
> ---
> v1 -> v2:
>   - Changed gi2c->se.dev to dev during dev_dbg() calls.
>   - Addressed review comments from Andi and Bjorn.
>   - Returned 0 instead garbage inside geni_i2c_force_resume().
>   - Added comments explaining forced resume transfer when runtime PM
>     remains disabled.
> Link to V1: https://patches.linaro.org/project/linux-i2c/patch/20240328123743.1713696-1-quic_msavaliy@quicinc.com/
> ---
> ---
>   drivers/dma/qcom/gpi.c             |  3 ++-
>   drivers/i2c/busses/i2c-qcom-geni.c | 12 +++++++++++-
>   2 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/qcom/gpi.c b/drivers/dma/qcom/gpi.c
> index c9a6f610ffd9..332f3aa40628 100644
> --- a/drivers/dma/qcom/gpi.c
> +++ b/drivers/dma/qcom/gpi.c
> @@ -615,7 +615,8 @@ static int gpi_config_interrupts(struct gpii *gpii, enum gpii_irq_settings setti
>   
>   	if (!gpii->configured_irq) {
>   		ret = devm_request_irq(gpii->gpi_dev->dev, gpii->irq,
> -				       gpi_handle_irq, IRQF_TRIGGER_HIGH,
> +				       gpi_handle_irq,
> +				       IRQF_TRIGGER_HIGH | IRQF_NO_SUSPEND | IRQF_EARLY_RESUME,
>   				       "gpi-dma", gpii);
>   		if (ret < 0) {
>   			dev_err(gpii->gpi_dev->dev, "error request irq:%d ret:%d\n",
> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
> index d2f5055b0b10..d56b36bd1d26 100644
> --- a/drivers/i2c/busses/i2c-qcom-geni.c
> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
> @@ -913,6 +913,10 @@ static int geni_i2c_xfer(struct i2c_adapter *adap,
>   	gi2c->err = 0;
>   	reinit_completion(&gi2c->done);
>   	ret = pm_runtime_get_sync(gi2c->se.dev);
> +	if (ret == -EACCES) {
> +		dev_warn(gi2c->se.dev, "Runtime PM is disabled:%d\n", ret);
> +		ret = 0;
> +	}
>   	if (ret < 0) {
>   		dev_err(gi2c->se.dev, "error turning SE resources:%d\n", ret);
>   		pm_runtime_put_noidle(gi2c->se.dev);
> @@ -1045,7 +1049,8 @@ static int geni_i2c_probe(struct platform_device *pdev)
>   	platform_set_drvdata(pdev, gi2c);
>   
>   	/* Keep interrupts disabled initially to allow for low-power modes */
> -	ret = devm_request_irq(dev, gi2c->irq, geni_i2c_irq, IRQF_NO_AUTOEN,
> +	ret = devm_request_irq(dev, gi2c->irq, geni_i2c_irq,
> +			       IRQF_NO_AUTOEN | IRQF_NO_SUSPEND | IRQF_EARLY_RESUME,
>   			       dev_name(dev), gi2c);
>   	if (ret)
>   		return dev_err_probe(dev, ret,
> @@ -1257,7 +1262,12 @@ static int __maybe_unused geni_i2c_resume_noirq(struct device *dev)
>   	if (ret)
>   		return ret;
>   
> +	/* Enforced disable_depth = 0 to actually enable runtime PM during noirq phase */
> +	if (!pm_runtime_enabled(dev))
> +		pm_runtime_enable(dev);
> +
>   	i2c_mark_adapter_resumed(&gi2c->adap);
> +
>   	return 0;
>   }
>   

Acked-by: Aniket Randive <aniketrandive@oss.qualcomm.com>