mmc: sdhci: add support for realtek rts5250

Add support for realtek rts5250 pci card reader. The card reader has
some problems with DDR50 mode, so add a new quirks2 for broken ddr50.

Signed-off-by: Micky Ching <[e-mail]>
Signed-off-by: Chris Ball <[e-mail]>

drivers/mmc/host/sdhci-pci.c

···
 	.probe		= via_probe,
 };
 
+static int rtsx_probe_slot(struct sdhci_pci_slot *slot)
+{
+	slot->host->mmc->caps2 |= MMC_CAP2_HS200;
+	return 0;
+}
+
+static const struct sdhci_pci_fixes sdhci_rtsx = {
+	.quirks2	= SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
+			SDHCI_QUIRK2_BROKEN_DDR50,
+	.probe_slot	= rtsx_probe_slot,
+};
+
 static const struct pci_device_id pci_ids[] = {
 	{
 		.vendor		= PCI_VENDOR_ID_RICOH,
···
 		.subvendor	= PCI_ANY_ID,
 		.subdevice	= PCI_ANY_ID,
 		.driver_data	= (kernel_ulong_t)&sdhci_via,
+	},
+
+	{
+		.vendor		= PCI_VENDOR_ID_REALTEK,
+		.device		= 0x5250,
+		.subvendor	= PCI_ANY_ID,
+		.subdevice	= PCI_ANY_ID,
+		.driver_data	= (kernel_ulong_t)&sdhci_rtsx,
 	},
 
 	{

drivers/mmc/host/sdhci.c

···
 	} else if (caps[1] & SDHCI_SUPPORT_SDR50)
 		mmc->caps |= MMC_CAP_UHS_SDR50;
 
-	if (caps[1] & SDHCI_SUPPORT_DDR50)
+	if ((caps[1] & SDHCI_SUPPORT_DDR50) &&
+		!(host->quirks2 & SDHCI_QUIRK2_BROKEN_DDR50))
 		mmc->caps |= MMC_CAP_UHS_DDR50;
 
 	/* Does the host need tuning for SDR50? */

include/linux/mmc/sdhci.h

···
 #define SDHCI_QUIRK2_BROKEN_HOST_CONTROL		(1<<5)
 /* Controller does not support HS200 */
 #define SDHCI_QUIRK2_BROKEN_HS200			(1<<6)
+/* Controller does not support DDR50 */
+#define SDHCI_QUIRK2_BROKEN_DDR50			(1<<7)
 
 	int irq;		/* Device IRQ */
 	void __iomem *ioaddr;	/* Mapped address */