Revert "ACPI / LPSS: introduce a 'proxy' device to power on LPSS for DMA"

Revert commit 6c17ee44 (ACPI / LPSS: introduce a 'proxy' device
to power on LPSS for DMA), as it introduced registration and probe
ordering problems between devices on the LPSS that may lead to full
hard system hang on boot in some cases.

drivers/acpi/acpi_lpss.c

 /*
  * ACPI support for Intel Lynxpoint LPSS.
  *
- * Copyright (C) 2013, 2014, Intel Corporation
+ * Copyright (C) 2013, Intel Corporation
  * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
  *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  *
@@ -60,8 +60,6 @@ ACPI_MODULE_NAME("acpi_lpss");
 #define LPSS_CLK_DIVIDER		BIT(2)
 #define LPSS_LTR			BIT(3)
 #define LPSS_SAVE_CTX			BIT(4)
-#define LPSS_DEV_PROXY			BIT(5)
-#define LPSS_PROXY_REQ			BIT(6)
 
 struct lpss_private_data;
 
@@ -72,10 +70,8 @@ struct lpss_device_desc {
 	void (*setup)(struct lpss_private_data *pdata);
 };
 
-static struct device *proxy_device;
-
 static struct lpss_device_desc lpss_dma_desc = {
-	.flags = LPSS_CLK | LPSS_PROXY_REQ,
+	.flags = LPSS_CLK,
 };
 
 struct lpss_private_data {
@@ -150,24 +146,22 @@ static struct lpss_device_desc byt_pwm_dev_desc = {
 };
 
 static struct lpss_device_desc byt_uart_dev_desc = {
-	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX |
-		 LPSS_DEV_PROXY,
+	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
 	.prv_offset = 0x800,
 	.setup = lpss_uart_setup,
 };
 
 static struct lpss_device_desc byt_spi_dev_desc = {
-	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX |
-		 LPSS_DEV_PROXY,
+	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
 	.prv_offset = 0x400,
 };
 
 static struct lpss_device_desc byt_sdio_dev_desc = {
-	.flags = LPSS_CLK | LPSS_DEV_PROXY,
+	.flags = LPSS_CLK,
 };
 
 static struct lpss_device_desc byt_i2c_dev_desc = {
-	.flags = LPSS_CLK | LPSS_SAVE_CTX | LPSS_DEV_PROXY,
+	.flags = LPSS_CLK | LPSS_SAVE_CTX,
 	.prv_offset = 0x800,
 	.setup = byt_i2c_setup,
 };
@@ -374,8 +368,6 @@ static int acpi_lpss_create_device(struct acpi_device *adev,
 	adev->driver_data = pdata;
 	pdev = acpi_create_platform_device(adev);
 	if (!IS_ERR_OR_NULL(pdev)) {
-		if (!proxy_device && dev_desc->flags & LPSS_DEV_PROXY)
-			proxy_device = &pdev->dev;
 		return 1;
 	}
 
@@ -600,14 +592,7 @@ static int acpi_lpss_runtime_suspend(struct device *dev)
 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
 		acpi_lpss_save_ctx(dev, pdata);
 
-	ret = acpi_dev_runtime_suspend(dev);
-	if (ret)
-		return ret;
-
-	if (pdata->dev_desc->flags & LPSS_PROXY_REQ && proxy_device)
-		return pm_runtime_put_sync_suspend(proxy_device);
-
-	return 0;
+	return acpi_dev_runtime_suspend(dev);
 }
 
 static int acpi_lpss_runtime_resume(struct device *dev)
@@ -615,12 +600,6 @@ static int acpi_lpss_runtime_resume(struct device *dev)
 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
 	int ret;
 
-	if (pdata->dev_desc->flags & LPSS_PROXY_REQ && proxy_device) {
-		ret = pm_runtime_get_sync(proxy_device);
-		if (ret)
-			return ret;
-	}
-
 	ret = acpi_dev_runtime_resume(dev);
 	if (ret)
 		return ret;