Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / acpi / acpi_lpss.c
diff --git a/kernel/drivers/acpi/acpi_lpss.c b/kernel/drivers/acpi/acpi_lpss.c
new file mode 100644 (file)
index 0000000..37fb190
--- /dev/null
@@ -0,0 +1,746 @@
+/*
+ * ACPI support for Intel Lynxpoint LPSS.
+ *
+ * Copyright (C) 2013, Intel Corporation
+ * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
+ *          Rafael J. Wysocki <rafael.j.wysocki@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/clk.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/clk-lpss.h>
+#include <linux/pm_runtime.h>
+#include <linux/delay.h>
+
+#include "internal.h"
+
+ACPI_MODULE_NAME("acpi_lpss");
+
+#ifdef CONFIG_X86_INTEL_LPSS
+
+#define LPSS_ADDR(desc) ((unsigned long)&desc)
+
+#define LPSS_CLK_SIZE  0x04
+#define LPSS_LTR_SIZE  0x18
+
+/* Offsets relative to LPSS_PRIVATE_OFFSET */
+#define LPSS_CLK_DIVIDER_DEF_MASK      (BIT(1) | BIT(16))
+#define LPSS_RESETS                    0x04
+#define LPSS_RESETS_RESET_FUNC         BIT(0)
+#define LPSS_RESETS_RESET_APB          BIT(1)
+#define LPSS_GENERAL                   0x08
+#define LPSS_GENERAL_LTR_MODE_SW       BIT(2)
+#define LPSS_GENERAL_UART_RTS_OVRD     BIT(3)
+#define LPSS_SW_LTR                    0x10
+#define LPSS_AUTO_LTR                  0x14
+#define LPSS_LTR_SNOOP_REQ             BIT(15)
+#define LPSS_LTR_SNOOP_MASK            0x0000FFFF
+#define LPSS_LTR_SNOOP_LAT_1US         0x800
+#define LPSS_LTR_SNOOP_LAT_32US                0xC00
+#define LPSS_LTR_SNOOP_LAT_SHIFT       5
+#define LPSS_LTR_SNOOP_LAT_CUTOFF      3000
+#define LPSS_LTR_MAX_VAL               0x3FF
+#define LPSS_TX_INT                    0x20
+#define LPSS_TX_INT_MASK               BIT(1)
+
+#define LPSS_PRV_REG_COUNT             9
+
+/* LPSS Flags */
+#define LPSS_CLK                       BIT(0)
+#define LPSS_CLK_GATE                  BIT(1)
+#define LPSS_CLK_DIVIDER               BIT(2)
+#define LPSS_LTR                       BIT(3)
+#define LPSS_SAVE_CTX                  BIT(4)
+
+struct lpss_private_data;
+
+struct lpss_device_desc {
+       unsigned int flags;
+       const char *clk_con_id;
+       unsigned int prv_offset;
+       size_t prv_size_override;
+       void (*setup)(struct lpss_private_data *pdata);
+};
+
+static struct lpss_device_desc lpss_dma_desc = {
+       .flags = LPSS_CLK,
+};
+
+struct lpss_private_data {
+       void __iomem *mmio_base;
+       resource_size_t mmio_size;
+       unsigned int fixed_clk_rate;
+       struct clk *clk;
+       const struct lpss_device_desc *dev_desc;
+       u32 prv_reg_ctx[LPSS_PRV_REG_COUNT];
+};
+
+/* UART Component Parameter Register */
+#define LPSS_UART_CPR                  0xF4
+#define LPSS_UART_CPR_AFCE             BIT(4)
+
+static void lpss_uart_setup(struct lpss_private_data *pdata)
+{
+       unsigned int offset;
+       u32 val;
+
+       offset = pdata->dev_desc->prv_offset + LPSS_TX_INT;
+       val = readl(pdata->mmio_base + offset);
+       writel(val | LPSS_TX_INT_MASK, pdata->mmio_base + offset);
+
+       val = readl(pdata->mmio_base + LPSS_UART_CPR);
+       if (!(val & LPSS_UART_CPR_AFCE)) {
+               offset = pdata->dev_desc->prv_offset + LPSS_GENERAL;
+               val = readl(pdata->mmio_base + offset);
+               val |= LPSS_GENERAL_UART_RTS_OVRD;
+               writel(val, pdata->mmio_base + offset);
+       }
+}
+
+static void lpss_deassert_reset(struct lpss_private_data *pdata)
+{
+       unsigned int offset;
+       u32 val;
+
+       offset = pdata->dev_desc->prv_offset + LPSS_RESETS;
+       val = readl(pdata->mmio_base + offset);
+       val |= LPSS_RESETS_RESET_APB | LPSS_RESETS_RESET_FUNC;
+       writel(val, pdata->mmio_base + offset);
+}
+
+#define LPSS_I2C_ENABLE                        0x6c
+
+static void byt_i2c_setup(struct lpss_private_data *pdata)
+{
+       lpss_deassert_reset(pdata);
+
+       if (readl(pdata->mmio_base + pdata->dev_desc->prv_offset))
+               pdata->fixed_clk_rate = 133000000;
+
+       writel(0, pdata->mmio_base + LPSS_I2C_ENABLE);
+}
+
+static struct lpss_device_desc lpt_dev_desc = {
+       .flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_LTR,
+       .prv_offset = 0x800,
+};
+
+static struct lpss_device_desc lpt_i2c_dev_desc = {
+       .flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_LTR,
+       .prv_offset = 0x800,
+};
+
+static struct lpss_device_desc lpt_uart_dev_desc = {
+       .flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_LTR,
+       .clk_con_id = "baudclk",
+       .prv_offset = 0x800,
+       .setup = lpss_uart_setup,
+};
+
+static struct lpss_device_desc lpt_sdio_dev_desc = {
+       .flags = LPSS_LTR,
+       .prv_offset = 0x1000,
+       .prv_size_override = 0x1018,
+};
+
+static struct lpss_device_desc byt_pwm_dev_desc = {
+       .flags = LPSS_SAVE_CTX,
+};
+
+static struct lpss_device_desc byt_uart_dev_desc = {
+       .flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
+       .clk_con_id = "baudclk",
+       .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,
+       .prv_offset = 0x400,
+};
+
+static struct lpss_device_desc byt_sdio_dev_desc = {
+       .flags = LPSS_CLK,
+};
+
+static struct lpss_device_desc byt_i2c_dev_desc = {
+       .flags = LPSS_CLK | LPSS_SAVE_CTX,
+       .prv_offset = 0x800,
+       .setup = byt_i2c_setup,
+};
+
+static struct lpss_device_desc bsw_spi_dev_desc = {
+       .flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
+       .prv_offset = 0x400,
+       .setup = lpss_deassert_reset,
+};
+
+#else
+
+#define LPSS_ADDR(desc) (0UL)
+
+#endif /* CONFIG_X86_INTEL_LPSS */
+
+static const struct acpi_device_id acpi_lpss_device_ids[] = {
+       /* Generic LPSS devices */
+       { "INTL9C60", LPSS_ADDR(lpss_dma_desc) },
+
+       /* Lynxpoint LPSS devices */
+       { "INT33C0", LPSS_ADDR(lpt_dev_desc) },
+       { "INT33C1", LPSS_ADDR(lpt_dev_desc) },
+       { "INT33C2", LPSS_ADDR(lpt_i2c_dev_desc) },
+       { "INT33C3", LPSS_ADDR(lpt_i2c_dev_desc) },
+       { "INT33C4", LPSS_ADDR(lpt_uart_dev_desc) },
+       { "INT33C5", LPSS_ADDR(lpt_uart_dev_desc) },
+       { "INT33C6", LPSS_ADDR(lpt_sdio_dev_desc) },
+       { "INT33C7", },
+
+       /* BayTrail LPSS devices */
+       { "80860F09", LPSS_ADDR(byt_pwm_dev_desc) },
+       { "80860F0A", LPSS_ADDR(byt_uart_dev_desc) },
+       { "80860F0E", LPSS_ADDR(byt_spi_dev_desc) },
+       { "80860F14", LPSS_ADDR(byt_sdio_dev_desc) },
+       { "80860F41", LPSS_ADDR(byt_i2c_dev_desc) },
+       { "INT33B2", },
+       { "INT33FC", },
+
+       /* Braswell LPSS devices */
+       { "80862288", LPSS_ADDR(byt_pwm_dev_desc) },
+       { "8086228A", LPSS_ADDR(byt_uart_dev_desc) },
+       { "8086228E", LPSS_ADDR(bsw_spi_dev_desc) },
+       { "808622C1", LPSS_ADDR(byt_i2c_dev_desc) },
+
+       { "INT3430", LPSS_ADDR(lpt_dev_desc) },
+       { "INT3431", LPSS_ADDR(lpt_dev_desc) },
+       { "INT3432", LPSS_ADDR(lpt_i2c_dev_desc) },
+       { "INT3433", LPSS_ADDR(lpt_i2c_dev_desc) },
+       { "INT3434", LPSS_ADDR(lpt_uart_dev_desc) },
+       { "INT3435", LPSS_ADDR(lpt_uart_dev_desc) },
+       { "INT3436", LPSS_ADDR(lpt_sdio_dev_desc) },
+       { "INT3437", },
+
+       /* Wildcat Point LPSS devices */
+       { "INT3438", LPSS_ADDR(lpt_dev_desc) },
+
+       { }
+};
+
+#ifdef CONFIG_X86_INTEL_LPSS
+
+static int is_memory(struct acpi_resource *res, void *not_used)
+{
+       struct resource r;
+       return !acpi_dev_resource_memory(res, &r);
+}
+
+/* LPSS main clock device. */
+static struct platform_device *lpss_clk_dev;
+
+static inline void lpt_register_clock_device(void)
+{
+       lpss_clk_dev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
+}
+
+static int register_device_clock(struct acpi_device *adev,
+                                struct lpss_private_data *pdata)
+{
+       const struct lpss_device_desc *dev_desc = pdata->dev_desc;
+       const char *devname = dev_name(&adev->dev);
+       struct clk *clk = ERR_PTR(-ENODEV);
+       struct lpss_clk_data *clk_data;
+       const char *parent, *clk_name;
+       void __iomem *prv_base;
+
+       if (!lpss_clk_dev)
+               lpt_register_clock_device();
+
+       clk_data = platform_get_drvdata(lpss_clk_dev);
+       if (!clk_data)
+               return -ENODEV;
+       clk = clk_data->clk;
+
+       if (!pdata->mmio_base
+           || pdata->mmio_size < dev_desc->prv_offset + LPSS_CLK_SIZE)
+               return -ENODATA;
+
+       parent = clk_data->name;
+       prv_base = pdata->mmio_base + dev_desc->prv_offset;
+
+       if (pdata->fixed_clk_rate) {
+               clk = clk_register_fixed_rate(NULL, devname, parent, 0,
+                                             pdata->fixed_clk_rate);
+               goto out;
+       }
+
+       if (dev_desc->flags & LPSS_CLK_GATE) {
+               clk = clk_register_gate(NULL, devname, parent, 0,
+                                       prv_base, 0, 0, NULL);
+               parent = devname;
+       }
+
+       if (dev_desc->flags & LPSS_CLK_DIVIDER) {
+               /* Prevent division by zero */
+               if (!readl(prv_base))
+                       writel(LPSS_CLK_DIVIDER_DEF_MASK, prv_base);
+
+               clk_name = kasprintf(GFP_KERNEL, "%s-div", devname);
+               if (!clk_name)
+                       return -ENOMEM;
+               clk = clk_register_fractional_divider(NULL, clk_name, parent,
+                                                     0, prv_base,
+                                                     1, 15, 16, 15, 0, NULL);
+               parent = clk_name;
+
+               clk_name = kasprintf(GFP_KERNEL, "%s-update", devname);
+               if (!clk_name) {
+                       kfree(parent);
+                       return -ENOMEM;
+               }
+               clk = clk_register_gate(NULL, clk_name, parent,
+                                       CLK_SET_RATE_PARENT | CLK_SET_RATE_GATE,
+                                       prv_base, 31, 0, NULL);
+               kfree(parent);
+               kfree(clk_name);
+       }
+out:
+       if (IS_ERR(clk))
+               return PTR_ERR(clk);
+
+       pdata->clk = clk;
+       clk_register_clkdev(clk, dev_desc->clk_con_id, devname);
+       return 0;
+}
+
+static int acpi_lpss_create_device(struct acpi_device *adev,
+                                  const struct acpi_device_id *id)
+{
+       struct lpss_device_desc *dev_desc;
+       struct lpss_private_data *pdata;
+       struct resource_entry *rentry;
+       struct list_head resource_list;
+       struct platform_device *pdev;
+       int ret;
+
+       dev_desc = (struct lpss_device_desc *)id->driver_data;
+       if (!dev_desc) {
+               pdev = acpi_create_platform_device(adev);
+               return IS_ERR_OR_NULL(pdev) ? PTR_ERR(pdev) : 1;
+       }
+       pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
+       if (!pdata)
+               return -ENOMEM;
+
+       INIT_LIST_HEAD(&resource_list);
+       ret = acpi_dev_get_resources(adev, &resource_list, is_memory, NULL);
+       if (ret < 0)
+               goto err_out;
+
+       list_for_each_entry(rentry, &resource_list, node)
+               if (resource_type(rentry->res) == IORESOURCE_MEM) {
+                       if (dev_desc->prv_size_override)
+                               pdata->mmio_size = dev_desc->prv_size_override;
+                       else
+                               pdata->mmio_size = resource_size(rentry->res);
+                       pdata->mmio_base = ioremap(rentry->res->start,
+                                                  pdata->mmio_size);
+                       if (!pdata->mmio_base)
+                               goto err_out;
+                       break;
+               }
+
+       acpi_dev_free_resource_list(&resource_list);
+
+       pdata->dev_desc = dev_desc;
+
+       if (dev_desc->setup)
+               dev_desc->setup(pdata);
+
+       if (dev_desc->flags & LPSS_CLK) {
+               ret = register_device_clock(adev, pdata);
+               if (ret) {
+                       /* Skip the device, but continue the namespace scan. */
+                       ret = 0;
+                       goto err_out;
+               }
+       }
+
+       /*
+        * This works around a known issue in ACPI tables where LPSS devices
+        * have _PS0 and _PS3 without _PSC (and no power resources), so
+        * acpi_bus_init_power() will assume that the BIOS has put them into D0.
+        */
+       ret = acpi_device_fix_up_power(adev);
+       if (ret) {
+               /* Skip the device, but continue the namespace scan. */
+               ret = 0;
+               goto err_out;
+       }
+
+       adev->driver_data = pdata;
+       pdev = acpi_create_platform_device(adev);
+       if (!IS_ERR_OR_NULL(pdev)) {
+               return 1;
+       }
+
+       ret = PTR_ERR(pdev);
+       adev->driver_data = NULL;
+
+ err_out:
+       kfree(pdata);
+       return ret;
+}
+
+static u32 __lpss_reg_read(struct lpss_private_data *pdata, unsigned int reg)
+{
+       return readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
+}
+
+static void __lpss_reg_write(u32 val, struct lpss_private_data *pdata,
+                            unsigned int reg)
+{
+       writel(val, pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
+}
+
+static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
+{
+       struct acpi_device *adev;
+       struct lpss_private_data *pdata;
+       unsigned long flags;
+       int ret;
+
+       ret = acpi_bus_get_device(ACPI_HANDLE(dev), &adev);
+       if (WARN_ON(ret))
+               return ret;
+
+       spin_lock_irqsave(&dev->power.lock, flags);
+       if (pm_runtime_suspended(dev)) {
+               ret = -EAGAIN;
+               goto out;
+       }
+       pdata = acpi_driver_data(adev);
+       if (WARN_ON(!pdata || !pdata->mmio_base)) {
+               ret = -ENODEV;
+               goto out;
+       }
+       *val = __lpss_reg_read(pdata, reg);
+
+ out:
+       spin_unlock_irqrestore(&dev->power.lock, flags);
+       return ret;
+}
+
+static ssize_t lpss_ltr_show(struct device *dev, struct device_attribute *attr,
+                            char *buf)
+{
+       u32 ltr_value = 0;
+       unsigned int reg;
+       int ret;
+
+       reg = strcmp(attr->attr.name, "auto_ltr") ? LPSS_SW_LTR : LPSS_AUTO_LTR;
+       ret = lpss_reg_read(dev, reg, &ltr_value);
+       if (ret)
+               return ret;
+
+       return snprintf(buf, PAGE_SIZE, "%08x\n", ltr_value);
+}
+
+static ssize_t lpss_ltr_mode_show(struct device *dev,
+                                 struct device_attribute *attr, char *buf)
+{
+       u32 ltr_mode = 0;
+       char *outstr;
+       int ret;
+
+       ret = lpss_reg_read(dev, LPSS_GENERAL, &ltr_mode);
+       if (ret)
+               return ret;
+
+       outstr = (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) ? "sw" : "auto";
+       return sprintf(buf, "%s\n", outstr);
+}
+
+static DEVICE_ATTR(auto_ltr, S_IRUSR, lpss_ltr_show, NULL);
+static DEVICE_ATTR(sw_ltr, S_IRUSR, lpss_ltr_show, NULL);
+static DEVICE_ATTR(ltr_mode, S_IRUSR, lpss_ltr_mode_show, NULL);
+
+static struct attribute *lpss_attrs[] = {
+       &dev_attr_auto_ltr.attr,
+       &dev_attr_sw_ltr.attr,
+       &dev_attr_ltr_mode.attr,
+       NULL,
+};
+
+static struct attribute_group lpss_attr_group = {
+       .attrs = lpss_attrs,
+       .name = "lpss_ltr",
+};
+
+static void acpi_lpss_set_ltr(struct device *dev, s32 val)
+{
+       struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+       u32 ltr_mode, ltr_val;
+
+       ltr_mode = __lpss_reg_read(pdata, LPSS_GENERAL);
+       if (val < 0) {
+               if (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) {
+                       ltr_mode &= ~LPSS_GENERAL_LTR_MODE_SW;
+                       __lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
+               }
+               return;
+       }
+       ltr_val = __lpss_reg_read(pdata, LPSS_SW_LTR) & ~LPSS_LTR_SNOOP_MASK;
+       if (val >= LPSS_LTR_SNOOP_LAT_CUTOFF) {
+               ltr_val |= LPSS_LTR_SNOOP_LAT_32US;
+               val = LPSS_LTR_MAX_VAL;
+       } else if (val > LPSS_LTR_MAX_VAL) {
+               ltr_val |= LPSS_LTR_SNOOP_LAT_32US | LPSS_LTR_SNOOP_REQ;
+               val >>= LPSS_LTR_SNOOP_LAT_SHIFT;
+       } else {
+               ltr_val |= LPSS_LTR_SNOOP_LAT_1US | LPSS_LTR_SNOOP_REQ;
+       }
+       ltr_val |= val;
+       __lpss_reg_write(ltr_val, pdata, LPSS_SW_LTR);
+       if (!(ltr_mode & LPSS_GENERAL_LTR_MODE_SW)) {
+               ltr_mode |= LPSS_GENERAL_LTR_MODE_SW;
+               __lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
+       }
+}
+
+#ifdef CONFIG_PM
+/**
+ * acpi_lpss_save_ctx() - Save the private registers of LPSS device
+ * @dev: LPSS device
+ * @pdata: pointer to the private data of the LPSS device
+ *
+ * Most LPSS devices have private registers which may loose their context when
+ * the device is powered down. acpi_lpss_save_ctx() saves those registers into
+ * prv_reg_ctx array.
+ */
+static void acpi_lpss_save_ctx(struct device *dev,
+                              struct lpss_private_data *pdata)
+{
+       unsigned int i;
+
+       for (i = 0; i < LPSS_PRV_REG_COUNT; i++) {
+               unsigned long offset = i * sizeof(u32);
+
+               pdata->prv_reg_ctx[i] = __lpss_reg_read(pdata, offset);
+               dev_dbg(dev, "saving 0x%08x from LPSS reg at offset 0x%02lx\n",
+                       pdata->prv_reg_ctx[i], offset);
+       }
+}
+
+/**
+ * acpi_lpss_restore_ctx() - Restore the private registers of LPSS device
+ * @dev: LPSS device
+ * @pdata: pointer to the private data of the LPSS device
+ *
+ * Restores the registers that were previously stored with acpi_lpss_save_ctx().
+ */
+static void acpi_lpss_restore_ctx(struct device *dev,
+                                 struct lpss_private_data *pdata)
+{
+       unsigned int i;
+
+       /*
+        * The following delay is needed or the subsequent write operations may
+        * fail. The LPSS devices are actually PCI devices and the PCI spec
+        * expects 10ms delay before the device can be accessed after D3 to D0
+        * transition.
+        */
+       msleep(10);
+
+       for (i = 0; i < LPSS_PRV_REG_COUNT; i++) {
+               unsigned long offset = i * sizeof(u32);
+
+               __lpss_reg_write(pdata->prv_reg_ctx[i], pdata, offset);
+               dev_dbg(dev, "restoring 0x%08x to LPSS reg at offset 0x%02lx\n",
+                       pdata->prv_reg_ctx[i], offset);
+       }
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int acpi_lpss_suspend_late(struct device *dev)
+{
+       struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+       int ret;
+
+       ret = pm_generic_suspend_late(dev);
+       if (ret)
+               return ret;
+
+       if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
+               acpi_lpss_save_ctx(dev, pdata);
+
+       return acpi_dev_suspend_late(dev);
+}
+
+static int acpi_lpss_resume_early(struct device *dev)
+{
+       struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+       int ret;
+
+       ret = acpi_dev_resume_early(dev);
+       if (ret)
+               return ret;
+
+       if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
+               acpi_lpss_restore_ctx(dev, pdata);
+
+       return pm_generic_resume_early(dev);
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static int acpi_lpss_runtime_suspend(struct device *dev)
+{
+       struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+       int ret;
+
+       ret = pm_generic_runtime_suspend(dev);
+       if (ret)
+               return ret;
+
+       if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
+               acpi_lpss_save_ctx(dev, pdata);
+
+       return acpi_dev_runtime_suspend(dev);
+}
+
+static int acpi_lpss_runtime_resume(struct device *dev)
+{
+       struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+       int ret;
+
+       ret = acpi_dev_runtime_resume(dev);
+       if (ret)
+               return ret;
+
+       if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
+               acpi_lpss_restore_ctx(dev, pdata);
+
+       return pm_generic_runtime_resume(dev);
+}
+#endif /* CONFIG_PM */
+
+static struct dev_pm_domain acpi_lpss_pm_domain = {
+       .ops = {
+#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
+               .prepare = acpi_subsys_prepare,
+               .complete = acpi_subsys_complete,
+               .suspend = acpi_subsys_suspend,
+               .suspend_late = acpi_lpss_suspend_late,
+               .resume_early = acpi_lpss_resume_early,
+               .freeze = acpi_subsys_freeze,
+               .poweroff = acpi_subsys_suspend,
+               .poweroff_late = acpi_lpss_suspend_late,
+               .restore_early = acpi_lpss_resume_early,
+#endif
+               .runtime_suspend = acpi_lpss_runtime_suspend,
+               .runtime_resume = acpi_lpss_runtime_resume,
+#endif
+       },
+};
+
+static int acpi_lpss_platform_notify(struct notifier_block *nb,
+                                    unsigned long action, void *data)
+{
+       struct platform_device *pdev = to_platform_device(data);
+       struct lpss_private_data *pdata;
+       struct acpi_device *adev;
+       const struct acpi_device_id *id;
+
+       id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev);
+       if (!id || !id->driver_data)
+               return 0;
+
+       if (acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev))
+               return 0;
+
+       pdata = acpi_driver_data(adev);
+       if (!pdata)
+               return 0;
+
+       if (pdata->mmio_base &&
+           pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
+               dev_err(&pdev->dev, "MMIO size insufficient to access LTR\n");
+               return 0;
+       }
+
+       switch (action) {
+       case BUS_NOTIFY_ADD_DEVICE:
+               pdev->dev.pm_domain = &acpi_lpss_pm_domain;
+               if (pdata->dev_desc->flags & LPSS_LTR)
+                       return sysfs_create_group(&pdev->dev.kobj,
+                                                 &lpss_attr_group);
+               break;
+       case BUS_NOTIFY_DEL_DEVICE:
+               if (pdata->dev_desc->flags & LPSS_LTR)
+                       sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
+               pdev->dev.pm_domain = NULL;
+               break;
+       default:
+               break;
+       }
+
+       return 0;
+}
+
+static struct notifier_block acpi_lpss_nb = {
+       .notifier_call = acpi_lpss_platform_notify,
+};
+
+static void acpi_lpss_bind(struct device *dev)
+{
+       struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+
+       if (!pdata || !pdata->mmio_base || !(pdata->dev_desc->flags & LPSS_LTR))
+               return;
+
+       if (pdata->mmio_size >= pdata->dev_desc->prv_offset + LPSS_LTR_SIZE)
+               dev->power.set_latency_tolerance = acpi_lpss_set_ltr;
+       else
+               dev_err(dev, "MMIO size insufficient to access LTR\n");
+}
+
+static void acpi_lpss_unbind(struct device *dev)
+{
+       dev->power.set_latency_tolerance = NULL;
+}
+
+static struct acpi_scan_handler lpss_handler = {
+       .ids = acpi_lpss_device_ids,
+       .attach = acpi_lpss_create_device,
+       .bind = acpi_lpss_bind,
+       .unbind = acpi_lpss_unbind,
+};
+
+void __init acpi_lpss_init(void)
+{
+       if (!lpt_clk_init()) {
+               bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
+               acpi_scan_add_handler(&lpss_handler);
+       }
+}
+
+#else
+
+static struct acpi_scan_handler lpss_handler = {
+       .ids = acpi_lpss_device_ids,
+};
+
+void __init acpi_lpss_init(void)
+{
+       acpi_scan_add_handler(&lpss_handler);
+}
+
+#endif /* CONFIG_X86_INTEL_LPSS */