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power: sequencing: qcom-wcn: explain why we need the WLAN_EN GPIO hack

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With the recent rework of the PCI power control code, the workaround for
the wlan-enable GPIO - where we don't set a default (low) state in the
power sequencing driver, but instead request the pin as-is - should no
longer be needed but some platforms still fail to probe the WLAN
controller. This is caused by the Qcom PCIe controller and needs a
workaround in the controller driver so add a FIXME to eventually remove
the hack from this driver once this is done.

Link: https://lore.kernel.org/r/20250102121530.26993-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Bartosz Golaszewski 2025-01-02 13:15:30 +01:00
parent 93e3c990fc
commit 29da3e8748
1 changed files with 7 additions and 0 deletions
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7
drivers/power/sequencing/pwrseq-qcom-wcn.c
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@ -396,6 +396,13 @@ static int pwrseq_qcom_wcn_probe(struct platform_device *pdev)
return dev_err_probe(dev, PTR_ERR(ctx->bt_gpio),
"Failed to get the Bluetooth enable GPIO\n");
/*
* FIXME: This should actually be GPIOD_OUT_LOW, but doing so would
* cause the WLAN power to be toggled, resulting in PCIe link down.
* Since the PCIe controller driver is not handling link down currently,
* the device becomes unusable. So we need to keep this workaround until
* the link down handling is implemented in the controller driver.
*/
ctx->wlan_gpio = devm_gpiod_get_optional(dev, "wlan-enable",
GPIOD_ASIS);
if (IS_ERR(ctx->wlan_gpio))