[PATCH V23 03/16] mmc: sdhci: add UHS-II module and add a kernel configuration

[Victor Shih <victorshihgli@gmail.com>]

From: Victor Shih <victor.shih@genesyslogic.com.tw>

This patch adds sdhci-uhs2.c as a module for UHS-II support.
This is a skeleton for further development in this patch series.

This kernel configuration, CONFIG_MMC_SDHCI_UHS2, will be used
in the following commits to indicate UHS-II specific code in sdhci
controllers.

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Victor Shih <victor.shih@genesyslogic.com.tw>
---

Updates in V22:
 - Remove defined but not used code.

Updates in V9:
 - Modify the commit message.

Updates in V8:
 - Modify MODULE_LICENSE from "GPL v2" to "GPL".

Updates in V6:
 - Merage V5 of patch[7] and patch[9] in to V6 of patch[8].

---

 drivers/mmc/host/Kconfig      |  9 ++++++++
 drivers/mmc/host/Makefile     |  1 +
 drivers/mmc/host/sdhci-uhs2.c | 41 +++++++++++++++++++++++++++++++++++
 3 files changed, 51 insertions(+)
 create mode 100644 drivers/mmc/host/sdhci-uhs2.c

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 0ba5a9f769fb..45df8ddb8918 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -98,6 +98,15 @@ config MMC_SDHCI_BIG_ENDIAN_32BIT_BYTE_SWAPPER
 
 	  This is the case for the Nintendo Wii SDHCI.
 
+config MMC_SDHCI_UHS2
+	tristate "UHS2 support on SDHCI controller"
+	depends on MMC_SDHCI
+	help
+	  This option is selected by SDHCI controller drivers that want to
+	  support UHS2-capable devices.
+
+	  If you have a controller with this feature, say Y or M here.
+
 config MMC_SDHCI_PCI
 	tristate "SDHCI support on PCI bus"
 	depends on MMC_SDHCI && PCI
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index 3ccffebbe59b..5147467ec825 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_MMC_PXA)		+= pxamci.o
 obj-$(CONFIG_MMC_MXC)		+= mxcmmc.o
 obj-$(CONFIG_MMC_MXS)		+= mxs-mmc.o
 obj-$(CONFIG_MMC_SDHCI)		+= sdhci.o
+obj-$(CONFIG_MMC_SDHCI_UHS2)	+= sdhci-uhs2.o
 obj-$(CONFIG_MMC_SDHCI_PCI)	+= sdhci-pci.o
 sdhci-pci-y			+= sdhci-pci-core.o sdhci-pci-o2micro.o sdhci-pci-arasan.o \
 				   sdhci-pci-dwc-mshc.o sdhci-pci-gli.o
diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
new file mode 100644
index 000000000000..9ec1d6abb47c
--- /dev/null
+++ b/drivers/mmc/host/sdhci-uhs2.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  linux/drivers/mmc/host/sdhci_uhs2.c - Secure Digital Host Controller
+ *  Interface driver
+ *
+ *  Copyright (C) 2014 Intel Corp, All Rights Reserved.
+ *  Copyright (C) 2020 Genesys Logic, Inc.
+ *  Authors: Ben Chuang <ben.chuang@genesyslogic.com.tw>
+ *  Copyright (C) 2020 Linaro Limited
+ *  Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
+ */
+
+#include <linux/module.h>
+
+#include "sdhci.h"
+#include "sdhci-uhs2.h"
+
+#define DRIVER_NAME "sdhci_uhs2"
+#define DBG(f, x...) \
+	pr_debug(DRIVER_NAME " [%s()]: " f, __func__, ## x)
+
+/*****************************************************************************\
+ *                                                                           *
+ * Driver init/exit                                                          *
+ *                                                                           *
+\*****************************************************************************/
+
+static int __init sdhci_uhs2_mod_init(void)
+{
+	return 0;
+}
+module_init(sdhci_uhs2_mod_init);
+
+static void __exit sdhci_uhs2_mod_exit(void)
+{
+}
+module_exit(sdhci_uhs2_mod_exit);
+
+MODULE_AUTHOR("Intel, Genesys Logic, Linaro");
+MODULE_DESCRIPTION("MMC UHS-II Support");
+MODULE_LICENSE("GPL");
-- 
2.25.1