Merge branch 'acpi-pm'

* acpi-pm:
  ACPI / bus: Move duplicate code to a separate new function
  mfd: Add support for Intel Sunrisepoint LPSS devices
  dmaengine: add a driver for Intel integrated DMA 64-bit
  mfd: make mfd_remove_devices() iterate in reverse order
  driver core: implement device_for_each_child_reverse()
  klist: implement klist_prev()
  Driver core: wakeup the parent device before trying probe
  ACPI / PM: Attach ACPI power domain only once
  PM / QoS: Make it possible to expose device latency tolerance to userspace
  ACPI / PM: Update the copyright notice and description of power.c

7 files changed, 810 insertions, 1 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 3f68dd2..076f593 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -328,6 +328,29 @@ config INTEL_SOC_PMIC
 	  thermal, charger and related power management functions
 	  on these systems.
 
+config MFD_INTEL_LPSS
+	tristate
+	select COMMON_CLK
+	select MFD_CORE
+
+config MFD_INTEL_LPSS_ACPI
+	tristate "Intel Low Power Subsystem support in ACPI mode"
+	select MFD_INTEL_LPSS
+	depends on X86 && ACPI
+	help
+	  This driver supports Intel Low Power Subsystem (LPSS) devices such as
+	  I2C, SPI and HS-UART starting from Intel Sunrisepoint (Intel Skylake
+	  PCH) in ACPI mode.
+
+config MFD_INTEL_LPSS_PCI
+	tristate "Intel Low Power Subsystem support in PCI mode"
+	select MFD_INTEL_LPSS
+	depends on X86 && PCI
+	help
+	  This driver supports Intel Low Power Subsystem (LPSS) devices such as
+	  I2C, SPI and HS-UART starting from Intel Sunrisepoint (Intel Skylake
+	  PCH) in PCI mode.
+
 config MFD_INTEL_MSIC
 	bool "Intel MSIC"
 	depends on INTEL_SCU_IPC
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index ea40e07..9d730a2 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -161,6 +161,9 @@ obj-$(CONFIG_TPS65911_COMPARATOR)	+= tps65911-comparator.o
 obj-$(CONFIG_MFD_TPS65090)	+= tps65090.o
 obj-$(CONFIG_MFD_AAT2870_CORE)	+= aat2870-core.o
 obj-$(CONFIG_MFD_ATMEL_HLCDC)	+= atmel-hlcdc.o
+obj-$(CONFIG_MFD_INTEL_LPSS)	+= intel-lpss.o
+obj-$(CONFIG_MFD_INTEL_LPSS_PCI)	+= intel-lpss-pci.o
+obj-$(CONFIG_MFD_INTEL_LPSS_ACPI)	+= intel-lpss-acpi.o
 obj-$(CONFIG_MFD_INTEL_MSIC)	+= intel_msic.o
 obj-$(CONFIG_MFD_PALMAS)	+= palmas.o
 obj-$(CONFIG_MFD_VIPERBOARD)    += viperboard.o
diff --git a/drivers/mfd/intel-lpss-acpi.c b/drivers/mfd/intel-lpss-acpi.c
new file mode 100644
index 0000000..0d92d73
--- /dev/null
+++ b/drivers/mfd/intel-lpss-acpi.c
@@ -0,0 +1,84 @@
+/*
+ * Intel LPSS ACPI support.
+ *
+ * Copyright (C) 2015, Intel Corporation
+ *
+ * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *          Mika Westerberg <mika.westerberg@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/platform_device.h>
+
+#include "intel-lpss.h"
+
+static const struct intel_lpss_platform_info spt_info = {
+	.clk_rate = 120000000,
+};
+
+static const struct acpi_device_id intel_lpss_acpi_ids[] = {
+	/* SPT */
+	{ "INT3446", (kernel_ulong_t)&spt_info },
+	{ "INT3447", (kernel_ulong_t)&spt_info },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, intel_lpss_acpi_ids);
+
+static int intel_lpss_acpi_probe(struct platform_device *pdev)
+{
+	struct intel_lpss_platform_info *info;
+	const struct acpi_device_id *id;
+
+	id = acpi_match_device(intel_lpss_acpi_ids, &pdev->dev);
+	if (!id)
+		return -ENODEV;
+
+	info = devm_kmemdup(&pdev->dev, (void *)id->driver_data, sizeof(*info),
+			    GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	info->irq = platform_get_irq(pdev, 0);
+
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	return intel_lpss_probe(&pdev->dev, info);
+}
+
+static int intel_lpss_acpi_remove(struct platform_device *pdev)
+{
+	intel_lpss_remove(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+static INTEL_LPSS_PM_OPS(intel_lpss_acpi_pm_ops);
+
+static struct platform_driver intel_lpss_acpi_driver = {
+	.probe = intel_lpss_acpi_probe,
+	.remove = intel_lpss_acpi_remove,
+	.driver = {
+		.name = "intel-lpss",
+		.acpi_match_table = intel_lpss_acpi_ids,
+		.pm = &intel_lpss_acpi_pm_ops,
+	},
+};
+
+module_platform_driver(intel_lpss_acpi_driver);
+
+MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
+MODULE_DESCRIPTION("Intel LPSS ACPI driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/mfd/intel-lpss-pci.c b/drivers/mfd/intel-lpss-pci.c
new file mode 100644
index 0000000..9236dff
--- /dev/null
+++ b/drivers/mfd/intel-lpss-pci.c
@@ -0,0 +1,113 @@
+/*
+ * Intel LPSS PCI support.
+ *
+ * Copyright (C) 2015, Intel Corporation
+ *
+ * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *          Mika Westerberg <mika.westerberg@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+
+#include "intel-lpss.h"
+
+static int intel_lpss_pci_probe(struct pci_dev *pdev,
+				const struct pci_device_id *id)
+{
+	struct intel_lpss_platform_info *info;
+	int ret;
+
+	ret = pcim_enable_device(pdev);
+	if (ret)
+		return ret;
+
+	info = devm_kmemdup(&pdev->dev, (void *)id->driver_data, sizeof(*info),
+			    GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->mem = &pdev->resource[0];
+	info->irq = pdev->irq;
+
+	/* Probably it is enough to set this for iDMA capable devices only */
+	pci_set_master(pdev);
+
+	ret = intel_lpss_probe(&pdev->dev, info);
+	if (ret)
+		return ret;
+
+	pm_runtime_put(&pdev->dev);
+	pm_runtime_allow(&pdev->dev);
+
+	return 0;
+}
+
+static void intel_lpss_pci_remove(struct pci_dev *pdev)
+{
+	pm_runtime_forbid(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
+
+	intel_lpss_remove(&pdev->dev);
+}
+
+static INTEL_LPSS_PM_OPS(intel_lpss_pci_pm_ops);
+
+static const struct intel_lpss_platform_info spt_info = {
+	.clk_rate = 120000000,
+};
+
+static const struct intel_lpss_platform_info spt_uart_info = {
+	.clk_rate = 120000000,
+	.clk_con_id = "baudclk",
+};
+
+static const struct pci_device_id intel_lpss_pci_ids[] = {
+	/* SPT-LP */
+	{ PCI_VDEVICE(INTEL, 0x9d27), (kernel_ulong_t)&spt_uart_info },
+	{ PCI_VDEVICE(INTEL, 0x9d28), (kernel_ulong_t)&spt_uart_info },
+	{ PCI_VDEVICE(INTEL, 0x9d29), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0x9d2a), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0x9d60), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0x9d61), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0x9d62), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0x9d63), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0x9d64), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0x9d65), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0x9d66), (kernel_ulong_t)&spt_uart_info },
+	/* SPT-H */
+	{ PCI_VDEVICE(INTEL, 0xa127), (kernel_ulong_t)&spt_uart_info },
+	{ PCI_VDEVICE(INTEL, 0xa128), (kernel_ulong_t)&spt_uart_info },
+	{ PCI_VDEVICE(INTEL, 0xa129), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0xa12a), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0xa160), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0xa161), (kernel_ulong_t)&spt_info },
+	{ PCI_VDEVICE(INTEL, 0xa166), (kernel_ulong_t)&spt_uart_info },
+	{ }
+};
+MODULE_DEVICE_TABLE(pci, intel_lpss_pci_ids);
+
+static struct pci_driver intel_lpss_pci_driver = {
+	.name = "intel-lpss",
+	.id_table = intel_lpss_pci_ids,
+	.probe = intel_lpss_pci_probe,
+	.remove = intel_lpss_pci_remove,
+	.driver = {
+		.pm = &intel_lpss_pci_pm_ops,
+	},
+};
+
+module_pci_driver(intel_lpss_pci_driver);
+
+MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
+MODULE_DESCRIPTION("Intel LPSS PCI driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/mfd/intel-lpss.c b/drivers/mfd/intel-lpss.c
new file mode 100644
index 0000000..fdf4d5c
--- /dev/null
+++ b/drivers/mfd/intel-lpss.c
@@ -0,0 +1,524 @@
+/*
+ * Intel Sunrisepoint LPSS core support.
+ *
+ * Copyright (C) 2015, Intel Corporation
+ *
+ * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *          Mika Westerberg <mika.westerberg@linux.intel.com>
+ *          Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ *          Jarkko Nikula <jarkko.nikula@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/debugfs.h>
+#include <linux/idr.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mfd/core.h>
+#include <linux/pm_qos.h>
+#include <linux/pm_runtime.h>
+#include <linux/seq_file.h>
+
+#include "intel-lpss.h"
+
+#define LPSS_DEV_OFFSET		0x000
+#define LPSS_DEV_SIZE		0x200
+#define LPSS_PRIV_OFFSET	0x200
+#define LPSS_PRIV_SIZE		0x100
+#define LPSS_IDMA64_OFFSET	0x800
+#define LPSS_IDMA64_SIZE	0x800
+
+/* Offsets from lpss->priv */
+#define LPSS_PRIV_RESETS		0x04
+#define LPSS_PRIV_RESETS_FUNC		BIT(2)
+#define LPSS_PRIV_RESETS_IDMA		0x3
+
+#define LPSS_PRIV_ACTIVELTR		0x10
+#define LPSS_PRIV_IDLELTR		0x14
+
+#define LPSS_PRIV_LTR_REQ		BIT(15)
+#define LPSS_PRIV_LTR_SCALE_MASK	0xc00
+#define LPSS_PRIV_LTR_SCALE_1US		0x800
+#define LPSS_PRIV_LTR_SCALE_32US	0xc00
+#define LPSS_PRIV_LTR_VALUE_MASK	0x3ff
+
+#define LPSS_PRIV_SSP_REG		0x20
+#define LPSS_PRIV_SSP_REG_DIS_DMA_FIN	BIT(0)
+
+#define LPSS_PRIV_REMAP_ADDR_LO		0x40
+#define LPSS_PRIV_REMAP_ADDR_HI		0x44
+
+#define LPSS_PRIV_CAPS			0xfc
+#define LPSS_PRIV_CAPS_NO_IDMA		BIT(8)
+#define LPSS_PRIV_CAPS_TYPE_SHIFT	4
+#define LPSS_PRIV_CAPS_TYPE_MASK	(0xf << LPSS_PRIV_CAPS_TYPE_SHIFT)
+
+/* This matches the type field in CAPS register */
+enum intel_lpss_dev_type {
+	LPSS_DEV_I2C = 0,
+	LPSS_DEV_UART,
+	LPSS_DEV_SPI,
+};
+
+struct intel_lpss {
+	const struct intel_lpss_platform_info *info;
+	enum intel_lpss_dev_type type;
+	struct clk *clk;
+	struct clk_lookup *clock;
+	const struct mfd_cell *cell;
+	struct device *dev;
+	void __iomem *priv;
+	int devid;
+	u32 caps;
+	u32 active_ltr;
+	u32 idle_ltr;
+	struct dentry *debugfs;
+};
+
+static const struct resource intel_lpss_dev_resources[] = {
+	DEFINE_RES_MEM_NAMED(LPSS_DEV_OFFSET, LPSS_DEV_SIZE, "lpss_dev"),
+	DEFINE_RES_MEM_NAMED(LPSS_PRIV_OFFSET, LPSS_PRIV_SIZE, "lpss_priv"),
+	DEFINE_RES_IRQ(0),
+};
+
+static const struct resource intel_lpss_idma64_resources[] = {
+	DEFINE_RES_MEM(LPSS_IDMA64_OFFSET, LPSS_IDMA64_SIZE),
+	DEFINE_RES_IRQ(0),
+};
+
+#define LPSS_IDMA64_DRIVER_NAME		"idma64"
+
+/*
+ * Cells needs to be ordered so that the iDMA is created first. This is
+ * because we need to be sure the DMA is available when the host controller
+ * driver is probed.
+ */
+static const struct mfd_cell intel_lpss_idma64_cell = {
+	.name = LPSS_IDMA64_DRIVER_NAME,
+	.num_resources = ARRAY_SIZE(intel_lpss_idma64_resources),
+	.resources = intel_lpss_idma64_resources,
+};
+
+static const struct mfd_cell intel_lpss_i2c_cell = {
+	.name = "i2c_designware",
+	.num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
+	.resources = intel_lpss_dev_resources,
+};
+
+static const struct mfd_cell intel_lpss_uart_cell = {
+	.name = "dw-apb-uart",
+	.num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
+	.resources = intel_lpss_dev_resources,
+};
+
+static const struct mfd_cell intel_lpss_spi_cell = {
+	.name = "pxa2xx-spi",
+	.num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
+	.resources = intel_lpss_dev_resources,
+};
+
+static DEFINE_IDA(intel_lpss_devid_ida);
+static struct dentry *intel_lpss_debugfs;
+
+static int intel_lpss_request_dma_module(const char *name)
+{
+	static bool intel_lpss_dma_requested;
+
+	if (intel_lpss_dma_requested)
+		return 0;
+
+	intel_lpss_dma_requested = true;
+	return request_module("%s", name);
+}
+
+static void intel_lpss_cache_ltr(struct intel_lpss *lpss)
+{
+	lpss->active_ltr = readl(lpss->priv + LPSS_PRIV_ACTIVELTR);
+	lpss->idle_ltr = readl(lpss->priv + LPSS_PRIV_IDLELTR);
+}
+
+static int intel_lpss_debugfs_add(struct intel_lpss *lpss)
+{
+	struct dentry *dir;
+
+	dir = debugfs_create_dir(dev_name(lpss->dev), intel_lpss_debugfs);
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
+
+	/* Cache the values into lpss structure */
+	intel_lpss_cache_ltr(lpss);
+
+	debugfs_create_x32("capabilities", S_IRUGO, dir, &lpss->caps);
+	debugfs_create_x32("active_ltr", S_IRUGO, dir, &lpss->active_ltr);
+	debugfs_create_x32("idle_ltr", S_IRUGO, dir, &lpss->idle_ltr);
+
+	lpss->debugfs = dir;
+	return 0;
+}
+
+static void intel_lpss_debugfs_remove(struct intel_lpss *lpss)
+{
+	debugfs_remove_recursive(lpss->debugfs);
+}
+
+static void intel_lpss_ltr_set(struct device *dev, s32 val)
+{
+	struct intel_lpss *lpss = dev_get_drvdata(dev);
+	u32 ltr;
+
+	/*
+	 * Program latency tolerance (LTR) accordingly what has been asked
+	 * by the PM QoS layer or disable it in case we were passed
+	 * negative value or PM_QOS_LATENCY_ANY.
+	 */
+	ltr = readl(lpss->priv + LPSS_PRIV_ACTIVELTR);
+
+	if (val == PM_QOS_LATENCY_ANY || val < 0) {
+		ltr &= ~LPSS_PRIV_LTR_REQ;
+	} else {
+		ltr |= LPSS_PRIV_LTR_REQ;
+		ltr &= ~LPSS_PRIV_LTR_SCALE_MASK;
+		ltr &= ~LPSS_PRIV_LTR_VALUE_MASK;
+
+		if (val > LPSS_PRIV_LTR_VALUE_MASK)
+			ltr |= LPSS_PRIV_LTR_SCALE_32US | val >> 5;
+		else
+			ltr |= LPSS_PRIV_LTR_SCALE_1US | val;
+	}
+
+	if (ltr == lpss->active_ltr)
+		return;
+
+	writel(ltr, lpss->priv + LPSS_PRIV_ACTIVELTR);
+	writel(ltr, lpss->priv + LPSS_PRIV_IDLELTR);
+
+	/* Cache the values into lpss structure */
+	intel_lpss_cache_ltr(lpss);
+}
+
+static void intel_lpss_ltr_expose(struct intel_lpss *lpss)
+{
+	lpss->dev->power.set_latency_tolerance = intel_lpss_ltr_set;
+	dev_pm_qos_expose_latency_tolerance(lpss->dev);
+}
+
+static void intel_lpss_ltr_hide(struct intel_lpss *lpss)
+{
+	dev_pm_qos_hide_latency_tolerance(lpss->dev);
+	lpss->dev->power.set_latency_tolerance = NULL;
+}
+
+static int intel_lpss_assign_devs(struct intel_lpss *lpss)
+{
+	unsigned int type;
+
+	type = lpss->caps & LPSS_PRIV_CAPS_TYPE_MASK;
+	type >>= LPSS_PRIV_CAPS_TYPE_SHIFT;
+
+	switch (type) {
+	case LPSS_DEV_I2C:
+		lpss->cell = &intel_lpss_i2c_cell;
+		break;
+	case LPSS_DEV_UART:
+		lpss->cell = &intel_lpss_uart_cell;
+		break;
+	case LPSS_DEV_SPI:
+		lpss->cell = &intel_lpss_spi_cell;
+		break;
+	default:
+		return -ENODEV;
+	}
+
+	lpss->type = type;
+
+	return 0;
+}
+
+static bool intel_lpss_has_idma(const struct intel_lpss *lpss)
+{
+	return (lpss->caps & LPSS_PRIV_CAPS_NO_IDMA) == 0;
+}
+
+static void intel_lpss_set_remap_addr(const struct intel_lpss *lpss)
+{
+	resource_size_t addr = lpss->info->mem->start;
+
+	writel(addr, lpss->priv + LPSS_PRIV_REMAP_ADDR_LO);
+#if BITS_PER_LONG > 32
+	writel(addr >> 32, lpss->priv + LPSS_PRIV_REMAP_ADDR_HI);
+#else
+	writel(0, lpss->priv + LPSS_PRIV_REMAP_ADDR_HI);
+#endif
+}
+
+static void intel_lpss_deassert_reset(const struct intel_lpss *lpss)
+{
+	u32 value = LPSS_PRIV_RESETS_FUNC | LPSS_PRIV_RESETS_IDMA;
+
+	/* Bring out the device from reset */
+	writel(value, lpss->priv + LPSS_PRIV_RESETS);
+}
+
+static void intel_lpss_init_dev(const struct intel_lpss *lpss)
+{
+	u32 value = LPSS_PRIV_SSP_REG_DIS_DMA_FIN;
+
+	intel_lpss_deassert_reset(lpss);
+
+	if (!intel_lpss_has_idma(lpss))
+		return;
+
+	intel_lpss_set_remap_addr(lpss);
+
+	/* Make sure that SPI multiblock DMA transfers are re-enabled */
+	if (lpss->type == LPSS_DEV_SPI)
+		writel(value, lpss->priv + LPSS_PRIV_SSP_REG);
+}
+
+static void intel_lpss_unregister_clock_tree(struct clk *clk)
+{
+	struct clk *parent;
+
+	while (clk) {
+		parent = clk_get_parent(clk);
+		clk_unregister(clk);
+		clk = parent;
+	}
+}
+
+static int intel_lpss_register_clock_divider(struct intel_lpss *lpss,
+					     const char *devname,
+					     struct clk **clk)
+{
+	char name[32];
+	struct clk *tmp = *clk;
+
+	snprintf(name, sizeof(name), "%s-enable", devname);
+	tmp = clk_register_gate(NULL, name, __clk_get_name(tmp), 0,
+				lpss->priv, 0, 0, NULL);
+	if (IS_ERR(tmp))
+		return PTR_ERR(tmp);
+
+	snprintf(name, sizeof(name), "%s-div", devname);
+	tmp = clk_register_fractional_divider(NULL, name, __clk_get_name(tmp),
+					      0, lpss->priv, 1, 15, 16, 15, 0,
+					      NULL);
+	if (IS_ERR(tmp))
+		return PTR_ERR(tmp);
+	*clk = tmp;
+
+	snprintf(name, sizeof(name), "%s-update", devname);
+	tmp = clk_register_gate(NULL, name, __clk_get_name(tmp),
+				CLK_SET_RATE_PARENT, lpss->priv, 31, 0, NULL);
+	if (IS_ERR(tmp))
+		return PTR_ERR(tmp);
+	*clk = tmp;
+
+	return 0;
+}
+
+static int intel_lpss_register_clock(struct intel_lpss *lpss)
+{
+	const struct mfd_cell *cell = lpss->cell;
+	struct clk *clk;
+	char devname[24];
+	int ret;
+
+	if (!lpss->info->clk_rate)
+		return 0;
+
+	/* Root clock */
+	clk = clk_register_fixed_rate(NULL, dev_name(lpss->dev), NULL,
+				      CLK_IS_ROOT, lpss->info->clk_rate);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	snprintf(devname, sizeof(devname), "%s.%d", cell->name, lpss->devid);
+
+	/*
+	 * Support for clock divider only if it has some preset value.
+	 * Otherwise we assume that the divider is not used.
+	 */
+	if (lpss->type != LPSS_DEV_I2C) {
+		ret = intel_lpss_register_clock_divider(lpss, devname, &clk);
+		if (ret)
+			goto err_clk_register;
+	}
+
+	ret = -ENOMEM;
+
+	/* Clock for the host controller */
+	lpss->clock = clkdev_create(clk, lpss->info->clk_con_id, "%s", devname);
+	if (!lpss->clock)
+		goto err_clk_register;
+
+	lpss->clk = clk;
+
+	return 0;
+
+err_clk_register:
+	intel_lpss_unregister_clock_tree(clk);
+
+	return ret;
+}
+
+static void intel_lpss_unregister_clock(struct intel_lpss *lpss)
+{
+	if (IS_ERR_OR_NULL(lpss->clk))
+		return;
+
+	clkdev_drop(lpss->clock);
+	intel_lpss_unregister_clock_tree(lpss->clk);
+}
+
+int intel_lpss_probe(struct device *dev,
+		     const struct intel_lpss_platform_info *info)
+{
+	struct intel_lpss *lpss;
+	int ret;
+
+	if (!info || !info->mem || info->irq <= 0)
+		return -EINVAL;
+
+	lpss = devm_kzalloc(dev, sizeof(*lpss), GFP_KERNEL);
+	if (!lpss)
+		return -ENOMEM;
+
+	lpss->priv = devm_ioremap(dev, info->mem->start + LPSS_PRIV_OFFSET,
+				  LPSS_PRIV_SIZE);
+	if (!lpss->priv)
+		return -ENOMEM;
+
+	lpss->info = info;
+	lpss->dev = dev;
+	lpss->caps = readl(lpss->priv + LPSS_PRIV_CAPS);
+
+	dev_set_drvdata(dev, lpss);
+
+	ret = intel_lpss_assign_devs(lpss);
+	if (ret)
+		return ret;
+
+	intel_lpss_init_dev(lpss);
+
+	lpss->devid = ida_simple_get(&intel_lpss_devid_ida, 0, 0, GFP_KERNEL);
+	if (lpss->devid < 0)
+		return lpss->devid;
+
+	ret = intel_lpss_register_clock(lpss);
+	if (ret)
+		goto err_clk_register;
+
+	intel_lpss_ltr_expose(lpss);
+
+	ret = intel_lpss_debugfs_add(lpss);
+	if (ret)
+		dev_warn(dev, "Failed to create debugfs entries\n");
+
+	if (intel_lpss_has_idma(lpss)) {
+		/*
+		 * Ensure the DMA driver is loaded before the host
+		 * controller device appears, so that the host controller
+		 * driver can request its DMA channels as early as
+		 * possible.
+		 *
+		 * If the DMA module is not there that's OK as well.
+		 */
+		intel_lpss_request_dma_module(LPSS_IDMA64_DRIVER_NAME);
+
+		ret = mfd_add_devices(dev, lpss->devid, &intel_lpss_idma64_cell,
+				      1, info->mem, info->irq, NULL);
+		if (ret)
+			dev_warn(dev, "Failed to add %s, fallback to PIO\n",
+				 LPSS_IDMA64_DRIVER_NAME);
+	}
+
+	ret = mfd_add_devices(dev, lpss->devid, lpss->cell,
+			      1, info->mem, info->irq, NULL);
+	if (ret)
+		goto err_remove_ltr;
+
+	return 0;
+
+err_remove_ltr:
+	intel_lpss_debugfs_remove(lpss);
+	intel_lpss_ltr_hide(lpss);
+
+err_clk_register:
+	ida_simple_remove(&intel_lpss_devid_ida, lpss->devid);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(intel_lpss_probe);
+
+void intel_lpss_remove(struct device *dev)
+{
+	struct intel_lpss *lpss = dev_get_drvdata(dev);
+
+	mfd_remove_devices(dev);
+	intel_lpss_debugfs_remove(lpss);
+	intel_lpss_ltr_hide(lpss);
+	intel_lpss_unregister_clock(lpss);
+	ida_simple_remove(&intel_lpss_devid_ida, lpss->devid);
+}
+EXPORT_SYMBOL_GPL(intel_lpss_remove);
+
+static int resume_lpss_device(struct device *dev, void *data)
+{
+	pm_runtime_resume(dev);
+	return 0;
+}
+
+int intel_lpss_prepare(struct device *dev)
+{
+	/*
+	 * Resume both child devices before entering system sleep. This
+	 * ensures that they are in proper state before they get suspended.
+	 */
+	device_for_each_child_reverse(dev, NULL, resume_lpss_device);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(intel_lpss_prepare);
+
+int intel_lpss_suspend(struct device *dev)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(intel_lpss_suspend);
+
+int intel_lpss_resume(struct device *dev)
+{
+	struct intel_lpss *lpss = dev_get_drvdata(dev);
+
+	intel_lpss_init_dev(lpss);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(intel_lpss_resume);
+
+static int __init intel_lpss_init(void)
+{
+	intel_lpss_debugfs = debugfs_create_dir("intel_lpss", NULL);
+	return 0;
+}
+module_init(intel_lpss_init);
+
+static void __exit intel_lpss_exit(void)
+{
+	debugfs_remove(intel_lpss_debugfs);
+}
+module_exit(intel_lpss_exit);
+
+MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
+MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
+MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>");
+MODULE_DESCRIPTION("Intel LPSS core driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/mfd/intel-lpss.h b/drivers/mfd/intel-lpss.h
new file mode 100644
index 0000000..f28cb28
--- /dev/null
+++ b/drivers/mfd/intel-lpss.h
@@ -0,0 +1,62 @@
+/*
+ * Intel LPSS core support.
+ *
+ * Copyright (C) 2015, Intel Corporation
+ *
+ * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *          Mika Westerberg <mika.westerberg@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __MFD_INTEL_LPSS_H
+#define __MFD_INTEL_LPSS_H
+
+struct device;
+struct resource;
+
+struct intel_lpss_platform_info {
+	struct resource *mem;
+	int irq;
+	unsigned long clk_rate;
+	const char *clk_con_id;
+};
+
+int intel_lpss_probe(struct device *dev,
+		     const struct intel_lpss_platform_info *info);
+void intel_lpss_remove(struct device *dev);
+
+#ifdef CONFIG_PM
+int intel_lpss_prepare(struct device *dev);
+int intel_lpss_suspend(struct device *dev);
+int intel_lpss_resume(struct device *dev);
+
+#ifdef CONFIG_PM_SLEEP
+#define INTEL_LPSS_SLEEP_PM_OPS			\
+	.prepare = intel_lpss_prepare,		\
+	.suspend = intel_lpss_suspend,		\
+	.resume = intel_lpss_resume,		\
+	.freeze = intel_lpss_suspend,		\
+	.thaw = intel_lpss_resume,		\
+	.poweroff = intel_lpss_suspend,		\
+	.restore = intel_lpss_resume,
+#endif
+
+#define INTEL_LPSS_RUNTIME_PM_OPS		\
+	.runtime_suspend = intel_lpss_suspend,	\
+	.runtime_resume = intel_lpss_resume,
+
+#else /* !CONFIG_PM */
+#define INTEL_LPSS_SLEEP_PM_OPS
+#define INTEL_LPSS_RUNTIME_PM_OPS
+#endif /* CONFIG_PM */
+
+#define INTEL_LPSS_PM_OPS(name)			\
+const struct dev_pm_ops name = {		\
+	INTEL_LPSS_SLEEP_PM_OPS			\
+	INTEL_LPSS_RUNTIME_PM_OPS		\
+}
+
+#endif /* __MFD_INTEL_LPSS_H */
diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index 14fd5cb..c17635d 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -302,7 +302,7 @@ void mfd_remove_devices(struct device *parent)
 {
 	atomic_t *cnts = NULL;
 
-	device_for_each_child(parent, &cnts, mfd_remove_devices_fn);
+	device_for_each_child_reverse(parent, &cnts, mfd_remove_devices_fn);
 	kfree(cnts);
 }
 EXPORT_SYMBOL(mfd_remove_devices);