mmc: sdhci-pci: Support setting CD debounce delay

Some systems (e.g. 2021 MacBook Pro 14/16") have noncompliant connectors
where CD activates before the card is fully inserted. We need debounce
delay support on these to avoid detection failures when the card isn't
inserted very quickly.

Set the default to 200ms for all systems instead of 0. This is the
default on non-PCI platforms, and will probably help other systems too.
The naughty MacBooks will need closer to 750ms in the device tree to
be reliable...

Signed-off-by: Hector Martin <marcan@marcan.st>

Author: marcan

drivers/mmc/host/sdhci-pci-core.c

@@ -2063,6 +2063,7 @@ static struct sdhci_pci_slot *sdhci_pci_probe_slot(
 	struct sdhci_host *host;
 	int ret, bar = first_bar + slotno;
 	size_t priv_size = chip->fixes ? chip->fixes->priv_size : 0;
+	u32 cd_debounce_delay_ms;
 
 	if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) {
 		dev_err(&pdev->dev, "BAR %d is not iomem. Aborting.\n", bar);
@@ -2129,14 +2130,18 @@ static struct sdhci_pci_slot *sdhci_pci_probe_slot(
 	if (host->mmc->caps & MMC_CAP_CD_WAKE)
 		device_init_wakeup(&pdev->dev, true);
 
+	if (device_property_read_u32(&pdev->dev, "cd-debounce-delay-ms",
+				     &cd_debounce_delay_ms))
+		cd_debounce_delay_ms = 200;
+
 	if (slot->cd_idx >= 0) {
 		ret = mmc_gpiod_request_cd(host->mmc, "cd", slot->cd_idx,
 					   slot->cd_override_level, 0);
 		if (ret && ret != -EPROBE_DEFER)
 			ret = mmc_gpiod_request_cd(host->mmc, NULL,
 						   slot->cd_idx,
 						   slot->cd_override_level,
-						   0);
+						   cd_debounce_delay_ms * 1000);
 		if (ret == -EPROBE_DEFER)
 			goto remove;
 
@@ -2148,7 +2153,8 @@ static struct sdhci_pci_slot *sdhci_pci_probe_slot(
 		/* Allow all OF systems to use a CD GPIO if provided */
 
 		ret = mmc_gpiod_request_cd(host->mmc, "cd", 0,
-					   slot->cd_override_level, 0);
+					   slot->cd_override_level,
+					   cd_debounce_delay_ms * 1000);
 		if (ret == -EPROBE_DEFER)
 			goto remove;
 		else if (ret == 0)