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path: root/drivers/acpi/acpi_lpss.c
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Diffstat (limited to 'drivers/acpi/acpi_lpss.c')
-rw-r--r--drivers/acpi/acpi_lpss.c157
1 files changed, 150 insertions, 7 deletions
diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index 69e29f409d4c..a01d4d1343dd 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -19,6 +19,7 @@
#include <linux/platform_device.h>
#include <linux/platform_data/clk-lpss.h>
#include <linux/pm_runtime.h>
+#include <linux/delay.h>
#include "internal.h"
@@ -43,6 +44,8 @@ ACPI_MODULE_NAME("acpi_lpss");
#define LPSS_TX_INT 0x20
#define LPSS_TX_INT_MASK BIT(1)
+#define LPSS_PRV_REG_COUNT 9
+
struct lpss_shared_clock {
const char *name;
unsigned long rate;
@@ -58,6 +61,7 @@ struct lpss_device_desc {
unsigned int prv_offset;
size_t prv_size_override;
bool clk_gate;
+ bool save_ctx;
struct lpss_shared_clock *shared_clock;
void (*setup)(struct lpss_private_data *pdata);
};
@@ -72,6 +76,7 @@ struct lpss_private_data {
resource_size_t mmio_size;
struct clk *clk;
const struct lpss_device_desc *dev_desc;
+ u32 prv_reg_ctx[LPSS_PRV_REG_COUNT];
};
static void lpss_uart_setup(struct lpss_private_data *pdata)
@@ -116,6 +121,7 @@ static struct lpss_shared_clock pwm_clock = {
static struct lpss_device_desc byt_pwm_dev_desc = {
.clk_required = true,
+ .save_ctx = true,
.shared_clock = &pwm_clock,
};
@@ -128,6 +134,7 @@ static struct lpss_device_desc byt_uart_dev_desc = {
.clk_required = true,
.prv_offset = 0x800,
.clk_gate = true,
+ .save_ctx = true,
.shared_clock = &uart_clock,
.setup = lpss_uart_setup,
};
@@ -141,6 +148,7 @@ static struct lpss_device_desc byt_spi_dev_desc = {
.clk_required = true,
.prv_offset = 0x400,
.clk_gate = true,
+ .save_ctx = true,
.shared_clock = &spi_clock,
};
@@ -156,6 +164,7 @@ static struct lpss_shared_clock i2c_clock = {
static struct lpss_device_desc byt_i2c_dev_desc = {
.clk_required = true,
.prv_offset = 0x800,
+ .save_ctx = true,
.shared_clock = &i2c_clock,
};
@@ -449,6 +458,126 @@ static void acpi_lpss_set_ltr(struct device *dev, s32 val)
}
}
+#ifdef CONFIG_PM
+/**
+ * acpi_lpss_save_ctx() - Save the private registers of LPSS device
+ * @dev: 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 = acpi_driver_data(ACPI_COMPANION(dev));
+ 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
+ *
+ * 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 = acpi_driver_data(ACPI_COMPANION(dev));
+ 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)
+{
+ int ret = pm_generic_suspend_late(dev);
+
+ if (ret)
+ return ret;
+
+ acpi_lpss_save_ctx(dev);
+ return acpi_dev_suspend_late(dev);
+}
+
+static int acpi_lpss_restore_early(struct device *dev)
+{
+ int ret = acpi_dev_resume_early(dev);
+
+ if (ret)
+ return ret;
+
+ acpi_lpss_restore_ctx(dev);
+ return pm_generic_resume_early(dev);
+}
+#endif /* CONFIG_PM_SLEEP */
+
+#ifdef CONFIG_PM_RUNTIME
+static int acpi_lpss_runtime_suspend(struct device *dev)
+{
+ int ret = pm_generic_runtime_suspend(dev);
+
+ if (ret)
+ return ret;
+
+ acpi_lpss_save_ctx(dev);
+ return acpi_dev_runtime_suspend(dev);
+}
+
+static int acpi_lpss_runtime_resume(struct device *dev)
+{
+ int ret = acpi_dev_runtime_resume(dev);
+
+ if (ret)
+ return ret;
+
+ acpi_lpss_restore_ctx(dev);
+ return pm_generic_runtime_resume(dev);
+}
+#endif /* CONFIG_PM_RUNTIME */
+#endif /* CONFIG_PM */
+
+static struct dev_pm_domain acpi_lpss_pm_domain = {
+ .ops = {
+#ifdef CONFIG_PM_SLEEP
+ .suspend_late = acpi_lpss_suspend_late,
+ .restore_early = acpi_lpss_restore_early,
+ .prepare = acpi_subsys_prepare,
+ .complete = acpi_subsys_complete,
+ .suspend = acpi_subsys_suspend,
+ .resume_early = acpi_subsys_resume_early,
+ .freeze = acpi_subsys_freeze,
+ .poweroff = acpi_subsys_suspend,
+ .poweroff_late = acpi_subsys_suspend_late,
+#endif
+#ifdef CONFIG_PM_RUNTIME
+ .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)
{
@@ -456,7 +585,6 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb,
struct lpss_private_data *pdata;
struct acpi_device *adev;
const struct acpi_device_id *id;
- int ret = 0;
id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev);
if (!id || !id->driver_data)
@@ -466,7 +594,7 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb,
return 0;
pdata = acpi_driver_data(adev);
- if (!pdata || !pdata->mmio_base || !pdata->dev_desc->ltr_required)
+ if (!pdata || !pdata->mmio_base)
return 0;
if (pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
@@ -474,12 +602,27 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb,
return 0;
}
- if (action == BUS_NOTIFY_ADD_DEVICE)
- ret = sysfs_create_group(&pdev->dev.kobj, &lpss_attr_group);
- else if (action == BUS_NOTIFY_DEL_DEVICE)
- sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
+ switch (action) {
+ case BUS_NOTIFY_BOUND_DRIVER:
+ if (pdata->dev_desc->save_ctx)
+ pdev->dev.pm_domain = &acpi_lpss_pm_domain;
+ break;
+ case BUS_NOTIFY_UNBOUND_DRIVER:
+ if (pdata->dev_desc->save_ctx)
+ pdev->dev.pm_domain = NULL;
+ break;
+ case BUS_NOTIFY_ADD_DEVICE:
+ if (pdata->dev_desc->ltr_required)
+ return sysfs_create_group(&pdev->dev.kobj,
+ &lpss_attr_group);
+ case BUS_NOTIFY_DEL_DEVICE:
+ if (pdata->dev_desc->ltr_required)
+ sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
+ default:
+ break;
+ }
- return ret;
+ return 0;
}
static struct notifier_block acpi_lpss_nb = {