---
 drivers/spi/spi.c |  201 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 200 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 84c2861..e39a484 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c

@@ -35,6 +35,8 @@
 #include <linux/sched.h>
 #include <linux/delay.h>
 #include <linux/kthread.h>
+#include <linux/ioport.h>
+#include <linux/acpi.h>
 
 static void spidev_release(struct device *dev)
 {

@@ -93,6 +95,10 @@ static int spi_match_device(struct device *dev, struct device_driver *drv)
 	if (of_driver_match_device(dev, drv))
 		return 1;
 
+	/* Then try ACPI */
+	if (acpi_driver_match_device(dev, drv))
+		return 1;
+
 	if (sdrv->id_table)
 		return !!spi_match_id(sdrv->id_table, spi);
 

@@ -888,6 +894,196 @@ static void of_register_spi_devices(struct spi_master *master)
 static void of_register_spi_devices(struct spi_master *master) { }
 #endif
 
+#ifdef CONFIG_ACPI
+static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
+{
+	struct acpi_resource_spi_serialbus *sb;
+	struct spi_device *spi = data;
+
+	if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
+		return 0;
+
+	sb = &ares->data.spi_serial_bus;
+	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
+		return 0;
+
+	spi->chip_select = sb->device_selection;
+	spi->max_speed_hz = sb->connection_speed;
+
+	if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
+		spi->mode |= SPI_CPHA;
+	if (sb->clock_polarity == ACPI_SPI_START_HIGH)
+		spi->mode |= SPI_CPOL;
+	if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
+		spi->mode |= SPI_CS_HIGH;
+
+	return 1;
+}
+
+static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
+				       void *data, void **return_value)
+{
+	struct spi_master *master = data;
+	struct resource_list_entry *rentry;
+	struct list_head resource_list;
+	struct acpi_device *adev;
+	struct spi_device *spi;
+	int ret;
+
+	if (acpi_bus_get_device(handle, &adev))
+		return AE_OK;
+	if (acpi_bus_get_status(adev) || !adev->status.present)
+		return AE_OK;
+
+	spi = spi_alloc_device(master);
+	if (!spi) {
+		dev_err(&master->dev, "failed to allocate SPI device for %s\n",
+			dev_name(&adev->dev));
+		return AE_NO_MEMORY;
+	}
+
+	INIT_LIST_HEAD(&resource_list);
+	ret = acpi_dev_get_resources(adev, &resource_list,
+				     acpi_spi_add_resource, spi);
+	if (ret < 0)
+		goto fail_put_dev;
+
+	list_for_each_entry(rentry, &resource_list, node) {
+		struct resource *r = &rentry->res;
+
+		if (resource_type(r) == IORESOURCE_IRQ) {
+			spi->irq = r->start;
+			break;
+		}
+	}
+
+	acpi_dev_free_resource_list(&resource_list);
+
+	if (!spi->max_speed_hz)
+		goto fail_put_dev;
+
+	strlcpy(spi->modalias, dev_name(&adev->dev), sizeof(spi->modalias));
+	if (spi_add_device(spi)) {
+		dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
+			dev_name(&adev->dev));
+		goto fail_put_dev;
+	}
+
+	return AE_OK;
+
+fail_put_dev:
+	spi_dev_put(spi);
+
+	return AE_OK;
+}
+
+static void acpi_register_spi_devices(struct spi_master *master)
+{
+	acpi_status status;
+	acpi_handle handle;
+
+	handle = master->dev.acpi_handle;
+	if (!handle)
+		return;
+
+	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+				     acpi_spi_add_device, NULL,
+				     master, NULL);
+	if (ACPI_FAILURE(status))
+		dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
+}
+
+struct acpi_spi_find {
+	acpi_handle handle;
+	u16 chip_select;
+	bool found;
+};
+
+static int acpi_spi_find_child_address(struct acpi_resource *ares, void *data)
+{
+	struct acpi_resource_spi_serialbus *sb;
+	struct acpi_spi_find *spi_find = data;
+
+	if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
+		return 1;
+
+	sb = &ares->data.spi_serial_bus;
+	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
+		return 1;
+
+	if (sb->device_selection == spi_find->chip_select)
+		spi_find->found = true;
+
+	return 1;
+}
+
+static acpi_status acpi_spi_find_child(acpi_handle handle, u32 level,
+				       void *data, void **return_value)
+{
+	struct acpi_spi_find *spi_find = data;
+	struct list_head resource_list;
+	struct acpi_device *adev;
+	int ret;
+
+	if (acpi_bus_get_device(handle, &adev))
+		return AE_OK;
+	if (acpi_bus_get_status(adev) || !adev->status.present)
+		return AE_OK;
+
+	INIT_LIST_HEAD(&resource_list);
+	ret = acpi_dev_get_resources(adev, &resource_list,
+				     acpi_spi_find_child_address, spi_find);
+	if (ret < 0)
+		return AE_OK;
+
+	acpi_dev_free_resource_list(&resource_list);
+
+	if (spi_find->found) {
+		spi_find->handle = handle;
+		return AE_CTRL_TERMINATE;
+	}
+	return AE_OK;
+}
+
+static int acpi_spi_find_device(struct device *dev, acpi_handle *handle)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	struct spi_master *master = spi->master;
+	struct acpi_spi_find spi_find;
+	acpi_handle parent;
+	acpi_status status;
+
+	parent = master->dev.acpi_handle;
+	if (!parent)
+		return -ENODEV;
+
+	memset(&spi_find, 0, sizeof(spi_find));
+	spi_find.chip_select = spi->chip_select;
+
+	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, parent, 1,
+				     acpi_spi_find_child, NULL,
+				     &spi_find, NULL);
+	if (ACPI_FAILURE(status) || !spi_find.handle)
+		return -ENODEV;
+
+	*handle = spi_find.handle;
+	return 0;
+}
+
+static struct acpi_bus_type acpi_spi_bus = {
+	.bus = &spi_bus_type,
+	.find_device = acpi_spi_find_device,
+};
+
+static void acpi_spi_bus_register(void)
+{
+	register_acpi_bus_type(&acpi_spi_bus);
+}
+#else
+static inline void acpi_register_spi_devices(struct spi_master *master) {}
+static inline void acpi_spi_bus_register(void) {}
+#endif /* CONFIG_ACPI */
+
 static void spi_master_release(struct device *dev)
 {
 	struct spi_master *master;

@@ -1023,8 +1219,9 @@ int spi_register_master(struct spi_master *master)
 		spi_match_master_to_boardinfo(master, &bi->board_info);
 	mutex_unlock(&board_lock);
 
-	/* Register devices from the device tree */
+	/* Register devices from the device tree and ACPI */
 	of_register_spi_devices(master);
+	acpi_register_spi_devices(master);
 done:
 	return status;
 }

@@ -1550,6 +1747,8 @@ static int __init spi_init(void)
 	status = class_register(&spi_master_class);
 	if (status < 0)
 		goto err2;
+
+	acpi_spi_bus_register();
 	return 0;
 
 err2: