[PATCH] mmc: Added quirks for Ricoh 1180:e823 lower base clock frequency

[Manoj Iyer <manoj.iyer@canonical.com>]

Ricoh 1180:e823 does not recognize certain types of SD/MMC cards.
Lowering the SD base clock frequency from 200Mhz to 50Mhz fixes
this issue. This solution was suggest by Koji Matsumuro, Ricoh
Company,Ltd.

BugLink: http://launchpad.net/bugs/773524
Signed-off-by: Manoj Iyer <manoj.iyer@canonical.com>
Tested-by: Daniel Manrique <daniel.manrique@canonical.com>
Cc: Koji Matsumuro <matsumur@nts.ricoh.co.jp>
---
 drivers/pci/quirks.c |   24 ++++++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 02145e9..fe5bffa 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2758,6 +2758,30 @@ static void ricoh_mmc_fixup_r5c832(struct pci_dev *dev)
 
 	dev_notice(&dev->dev, "proprietary Ricoh MMC controller disabled (via firewire function)\n");
 	dev_notice(&dev->dev, "MMC cards are now supported by standard SDHCI controller\n");
+
+	/* 
+	 * RICOH 0xe823 SD/MMC card reader fails to recognize 
+	 * certain types of SD/MMC cards. Lowering the SD base
+	 * clock frequency from 200Mhz to 50Mhz fixes this issue.
+	 *
+	 * 0x150 - SD2.0 mode enable for changing base clock 
+	 *	   frequency to 50Mhz
+	 * 0xe1  - Base clock frequency
+	 * 0x32  - 50Mhz new clock frequency
+	 * 0xf9  - Key register for 0x150
+	 * 0xfc  - key register for 0xe1
+	 */
+	if (dev->device == PCI_DEVICE_ID_RICOH_R5CE823) {
+		pci_write_config_byte(dev, 0xf9, 0xfc);
+		pci_write_config_byte(dev, 0x150, 0x10);
+		pci_write_config_byte(dev, 0xf9, 0x00);
+		pci_write_config_byte(dev, 0xfc, 0x01);
+		pci_write_config_byte(dev, 0xe1, 0x32);
+		pci_write_config_byte(dev, 0xfc, 0x00);
+
+		dev_notice(&dev->dev, "Controller base frequency changed to 50Mhz)\n");
+	}
+
 }
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_RICOH, PCI_DEVICE_ID_RICOH_R5C832, ricoh_mmc_fixup_r5c832);
 DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_RICOH, PCI_DEVICE_ID_RICOH_R5C832, ricoh_mmc_fixup_r5c832);
-- 
1.7.4.1