[RFC PATCH 2/4] mmc: sdio: bind sdio device with acpi device

[Aaron Lu <aaron.lu@intel.com>]

ACPI spec defines the _ADDR encoding for sdio bus as:
High word - slot number (0 based)
Low word  - function number

This patch adds support for sdio device binding with acpi using the
generic ACPI glue framework.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
---
 drivers/mmc/core/Makefile    |  1 +
 drivers/mmc/core/sdio_acpi.c | 35 +++++++++++++++++++++++++++++++++++
 drivers/mmc/core/sdio_bus.c  | 14 ++++++++++++--
 drivers/mmc/core/sdio_bus.h  |  2 ++
 4 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 drivers/mmc/core/sdio_acpi.c

diff --git a/drivers/mmc/core/Makefile b/drivers/mmc/core/Makefile
index 38ed210..c8300aa 100644
--- a/drivers/mmc/core/Makefile
+++ b/drivers/mmc/core/Makefile
@@ -10,3 +10,4 @@ mmc_core-y			:= core.o bus.o host.o \
 				   quirks.o slot-gpio.o
 
 mmc_core-$(CONFIG_DEBUG_FS)	+= debugfs.o
+mmc_core-$(CONFIG_ACPI)		+= sdio_acpi.o
diff --git a/drivers/mmc/core/sdio_acpi.c b/drivers/mmc/core/sdio_acpi.c
new file mode 100644
index 0000000..0f92e90
--- /dev/null
+++ b/drivers/mmc/core/sdio_acpi.c
@@ -0,0 +1,35 @@
+#include <linux/mmc/host.h>
+#include <linux/mmc/card.h>
+#include <linux/mmc/sdhci.h>
+#include <linux/mmc/sdio_func.h>
+#include <linux/acpi.h>
+#include <acpi/acpi_bus.h>
+#include "sdio_bus.h"
+
+static int acpi_sdio_find_device(struct device *dev, acpi_handle *handle)
+{
+	struct sdio_func *func;
+	struct sdhci_host *host;
+	u64 addr;
+
+	func = dev_to_sdio_func(dev);
+	host = mmc_priv(func->card->host);
+
+	addr = (host->slotno << 16) | func->num;
+
+	*handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev), addr);
+	if (!*handle)
+		return -ENODEV;
+
+	return 0;
+}
+
+static struct acpi_bus_type acpi_sdio_bus = {
+	.bus = &sdio_bus_type,
+	.find_device = acpi_sdio_find_device,
+};
+
+int sdio_acpi_register(void)
+{
+	return register_acpi_bus_type(&acpi_sdio_bus);
+}
diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c
index 6bf6879..aaec9e2 100644
--- a/drivers/mmc/core/sdio_bus.c
+++ b/drivers/mmc/core/sdio_bus.c
@@ -23,6 +23,7 @@
 
 #include "sdio_cis.h"
 #include "sdio_bus.h"
+#include "sdio_acpi.h"
 
 /* show configuration fields */
 #define sdio_config_attr(field, format_string)				\
@@ -209,7 +210,7 @@ static const struct dev_pm_ops sdio_bus_pm_ops = {
 
 #endif /* !CONFIG_PM */
 
-static struct bus_type sdio_bus_type = {
+struct bus_type sdio_bus_type = {
 	.name		= "sdio",
 	.dev_attrs	= sdio_dev_attrs,
 	.match		= sdio_bus_match,
@@ -221,7 +222,16 @@ static struct bus_type sdio_bus_type = {
 
 int sdio_register_bus(void)
 {
-	return bus_register(&sdio_bus_type);
+	int ret;
+
+	ret = bus_register(&sdio_bus_type);
+	if (ret)
+		goto out;
+
+	ret = sdio_acpi_register();
+
+out:
+	return ret;
 }
 
 void sdio_unregister_bus(void)
diff --git a/drivers/mmc/core/sdio_bus.h b/drivers/mmc/core/sdio_bus.h
index 567a768..91c0e93 100644
--- a/drivers/mmc/core/sdio_bus.h
+++ b/drivers/mmc/core/sdio_bus.h
@@ -18,5 +18,7 @@ void sdio_remove_func(struct sdio_func *func);
 int sdio_register_bus(void);
 void sdio_unregister_bus(void);
 
+extern struct bus_type sdio_bus_type;
+
 #endif
 
-- 
1.7.12.21.g871e293