drivers/mfd/intel-lpss.c - LeafOS-Devices/android_kernel_samsung_universal7904 - Gitiles

 /*
  * 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 <linux/io-64-nonatomic-lo-hi.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_PRIV_REG_COUNT	(LPSS_PRIV_SIZE / 4)
 #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		0x40

 #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;
 	u32 priv_ctx[LPSS_PRIV_REG_COUNT];
 	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;

 	lo_hi_writeq(addr, lpss->priv + LPSS_PRIV_REMAP_ADDR);
 }

 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);

 	intel_lpss_set_remap_addr(lpss);

 	if (!intel_lpss_has_idma(lpss))
 		return;

 	/* 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);
 	intel_lpss_unregister_clock(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)
 {
 	struct intel_lpss *lpss = dev_get_drvdata(dev);
 	unsigned int i;

 	/* Save device context */
 	for (i = 0; i < LPSS_PRIV_REG_COUNT; i++)
 		lpss->priv_ctx[i] = readl(lpss->priv + i * 4);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(intel_lpss_suspend);

 int intel_lpss_resume(struct device *dev)
 {
 	struct intel_lpss *lpss = dev_get_drvdata(dev);
 	unsigned int i;

 	intel_lpss_deassert_reset(lpss);

 	/* Restore device context */
 	for (i = 0; i < LPSS_PRIV_REG_COUNT; i++)
 		writel(lpss->priv_ctx[i], lpss->priv + i * 4);

 	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");
	/*
	* 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 <linux/io-64-nonatomic-lo-hi.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_PRIV_REG_COUNT (LPSS_PRIV_SIZE / 4)
	#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 0x40

	#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;
	u32 priv_ctx[LPSS_PRIV_REG_COUNT];
	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;

	lo_hi_writeq(addr, lpss->priv + LPSS_PRIV_REMAP_ADDR);
	}

	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);

	intel_lpss_set_remap_addr(lpss);

	if (!intel_lpss_has_idma(lpss))
	return;

	/* 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);
	intel_lpss_unregister_clock(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)
	{
	struct intel_lpss *lpss = dev_get_drvdata(dev);
	unsigned int i;

	/* Save device context */
	for (i = 0; i < LPSS_PRIV_REG_COUNT; i++)
	lpss->priv_ctx[i] = readl(lpss->priv + i * 4);

	return 0;
	}
	EXPORT_SYMBOL_GPL(intel_lpss_suspend);

	int intel_lpss_resume(struct device *dev)
	{
	struct intel_lpss *lpss = dev_get_drvdata(dev);
	unsigned int i;

	intel_lpss_deassert_reset(lpss);

	/* Restore device context */
	for (i = 0; i < LPSS_PRIV_REG_COUNT; i++)
	writel(lpss->priv_ctx[i], lpss->priv + i * 4);

	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");