From 29da3e8748f97dcf01498b00d42a3e7574ece80b Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Thu, 2 Jan 2025 13:15:30 +0100 Subject: [PATCH] power: sequencing: qcom-wcn: explain why we need the WLAN_EN GPIO hack 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 --- drivers/power/sequencing/pwrseq-qcom-wcn.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/power/sequencing/pwrseq-qcom-wcn.c b/drivers/power/sequencing/pwrseq-qcom-wcn.c index cc03b5aaa8f2a..e8f5030f2639a 100644 --- a/drivers/power/sequencing/pwrseq-qcom-wcn.c +++ b/drivers/power/sequencing/pwrseq-qcom-wcn.c @@ -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)) -- 2.39.5