[PATCH v2 2/4] PCI: qcom: Keep PERST# GPIO state as-is during probe

[Krishna Chaitanya Chundru]

On 5/21/2026 7:13 PM, sashiko-bot at kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [High] Silent hardware control failure due to incorrect GPIO direction when using `GPIOD_ASIS`.
> --
>
> commit b4b7937282f9b2dc2dff52265ec3936b1024af9d
> Author: Krishna Chaitanya Chundru <krishna.chundru at oss.qualcomm.com>
>
> PCI: qcom: Keep PERST# GPIO state as-is during probe
>
> This commit changes the PERST# GPIO request to use GPIOD_ASIS instead of
> GPIOD_OUT_HIGH. This preserves the existing GPIO state configured by the
> bootloader or firmware to avoid unintentionally asserting reset during
> probe.
>
>> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
>> index af6bf5cce65be..bfe873cbf44f6 100644
>> --- a/drivers/pci/controller/dwc/pcie-qcom.c
>> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
>> @@ -1707,7 +1707,7 @@ static int qcom_pcie_parse_perst(struct qcom_pcie *pcie,
>>  		goto parse_child_node;
>>  
>>  	reset = devm_fwnode_gpiod_get(dev, of_fwnode_handle(np), "reset",
>> -				      GPIOD_OUT_HIGH, "PERST#");
>> +				      GPIOD_ASIS, "PERST#");
> [Severity: High]
> If the bootloader leaves the PERST# pin floating or as an input, will
> this cause gpiod_set_value_cansleep() to silently fail later?
>
> When using GPIOD_ASIS, if the pin was not previously configured as an
> output, GPIOD_FLAG_IS_OUT will not be set in the GPIO descriptor.
>
> Later in qcom_pcie_host_init(), the driver attempts to toggle the reset
> pin by calling gpiod_set_value_cansleep() via __qcom_pcie_perst_assert().
>
> Because gpiod_set_value_cansleep() enforces directionality, it will
> return -EPERM if the pin is not configured as an output. Since
> __qcom_pcie_perst_assert() ignores the return value of
> gpiod_set_value_cansleep(), the reset line might never actually be driven.
>
> Could this break PCIe link initialization on platforms where the
> bootloader hasn't set the GPIO direction to output?
There is pincntrl in the devicetree to make the direction OUT if bootloader
doesn't set
this pin out.

- Krishna Chaitanya.
>