mmc: USB SD Host Controller (USHC) driver

Add a driver for USB SD Host Controller devices.  These devices are
Cypress Astoria chips with firmware compliant with issue 2 of CSR's USHC
specification.

[cjb: adapt to block layer deprecation of max_{hw,phys}_segs]
Signed-off-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 68d12794cfd9..8de7b9e8fc51 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -451,3 +451,17 @@ config MMC_JZ4740
           SoCs.
           If you have a board based on such a SoC and with a SD/MMC slot,
           say Y or M here.
+
+config MMC_USHC
+        tristate "USB SD Host Controller (USHC) support"
+        depends on USB
+        help
+          This selects support for USB SD Host Controllers based on
+          the Cypress Astoria chip with firmware compliant with CSR's
+          USB SD Host Controller specification (CS-118793-SP).
+
+          CSR boards with this device include: USB<>SDIO (M1985v2),
+          and Ultrasira.
+
+          Note: These controllers only support SDIO cards and do not
+          support MMC or SD memory cards.