mmc: Add new VUB300 USB-to-SD/SDIO/MMC driver

Add a driver for Elan Digital System's VUB300 chip which is a USB
connected SDIO/SDmem/MMC host controller.  A VUB300 chip enables a USB 2.0
or USB 1.1 connected host computer to use SDIO/SD/MMC cards without the
need for a directly connected, for example via PCI, SDIO host controller.

Signed-off-by: Anthony F Olech <tony.olech@elandigitalsystems.com>
[cjb: various punctuation and style fixes]
Tested-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index b981715130c6..56dbf3f6ad08 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -535,6 +535,37 @@ config MMC_JZ4740
           If you have a board based on such a SoC and with a SD/MMC slot,
           say Y or M here.
 
+config MMC_VUB300
+        tristate "VUB300 USB to SDIO/SD/MMC Host Controller support"
+        depends on USB
+        help
+          This selects support for Elan Digital Systems' VUB300 chip.
+
+          The VUB300 is a USB-SDIO Host Controller Interface chip
+          that enables the host computer to use SDIO/SD/MMC cards
+          via a USB 2.0 or USB 1.1 host.
+
+          The VUB300 chip will be found in both physically separate
+          USB to SDIO/SD/MMC adapters and embedded on some motherboards.
+
+          The VUB300 chip supports SD and MMC memory cards in addition
+          to single and multifunction SDIO cards.
+
+          Some SDIO cards will need a firmware file to be loaded and
+          sent to VUB300 chip in order to achieve better data throughput.
+          Download these "Offload Pseudocode" from Elan Digital Systems'
+          web-site http://www.elandigitalsystems.com/support/downloads.php
+          and put them in /lib/firmware. Note that without these additional
+          firmware files the VUB300 chip will still function, but not at
+          the best obtainable data rate.
+
+          To compile this mmc host controller driver as a module,
+          choose M here: the module will be called vub300.
+
+          If you have a computer with an embedded VUB300 chip
+          or if you intend connecting a USB adapter based on a
+          VUB300 chip say Y or M here.
+
 config MMC_USHC
         tristate "USB SD Host Controller (USHC) support"
         depends on USB