This is a little rework of linux power scheme. TODO:
- remove recursive call
- clean-up code
Avoid suspend of a device that is connected with other coprocessor
like GSM chip.
Signed-off-by: Michael Trimarchi <trimarchi@xxxxxxxxxxxxxxxx>
---
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 3098c46..2a6ddb3 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -63,6 +63,40 @@ void device_pm_unlock(void)
mutex_unlock(&dpm_list_mtx);
}
+int device_set_may_suspend_enable(struct device *dev, void *data)
+{
+ /* if the device is suspend the subtree is in may_suspend status */
+ if (!dev->power.can_suspend)
+ goto out;
+
+ dev->power.may_suspend = (unsigned int)data;
+ device_for_each_child(dev, data,
+ device_set_may_suspend_enable);
+out:
+ return 0;
+}
+
+/**
+ * device_set_suspend_enable - enable/disable device to suspend
+ */
+int device_set_suspend_enable(struct device *dev, int enable)
+{
+ mutex_lock(&dpm_list_mtx);
+
+ if (dev->power.can_suspend == !!enable)
+ goto out;
+
+ /* Update device children to avoid suspend */
+ device_for_each_child(dev, (void *)!!enable,
+ device_set_may_suspend_enable);
+
+ dev->power.can_suspend = !!enable;
+out:
+ mutex_unlock(&dpm_list_mtx);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(device_set_suspend_enable);
+
/**
* device_pm_add - add a device to the list of active devices
* @dev: Device to be added to the list
@@ -77,6 +111,13 @@ void device_pm_add(struct device *dev)
if (dev->parent->power.status >= DPM_SUSPENDING)
dev_warn(dev, "parent %s should not be sleeping\n",
dev_name(dev->parent));
+ if (!device_can_suspend(dev->parent)) {
+ mutex_unlock(&dpm_list_mtx);
+ /* if the parent has suspend disable, propagate it
+ * to the new child */
+ device_set_may_suspend_enable(dev, 0);
+ mutex_lock(&dpm_list_mtx);
+ }
} else if (transition_started) {
/*
* We refuse to register parentless devices while a PM
@@ -120,13 +161,13 @@ static int pm_op(struct device *dev, struct dev_pm_ops *ops,
switch (state.event) {
#ifdef CONFIG_SUSPEND
case PM_EVENT_SUSPEND:
- if (ops->suspend) {
+ if (device_can_suspend(dev) && ops->suspend) {
error = ops->suspend(dev);
suspend_report_result(ops->suspend, error);
}
break;
case PM_EVENT_RESUME:
- if (ops->resume) {
+ if (device_can_suspend(dev) && ops->resume) {
error = ops->resume(dev);
suspend_report_result(ops->resume, error);
}
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index 41f51fa..1197b13 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -1,6 +1,13 @@
static inline void device_pm_init(struct device *dev)
{
dev->power.status = DPM_ON;
+ dev->power.can_suspend = 1;
+ dev->power.may_suspend = 1;
+}
+
+static inline int device_can_suspend(struct device *dev)
+{
+ return (dev->power.can_suspend && dev->power.may_suspend);
}
#ifdef CONFIG_PM_SLEEP
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index 596aeec..25236aa 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -43,6 +43,34 @@
static const char enabled[] = "enabled";
static const char disabled[] = "disabled";
+static ssize_t suspend_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%s\n", device_can_suspend(dev)
+ ? enabled : disabled);
+}
+
+static ssize_t
+suspend_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t n)
+{
+ char *cp;
+ int len = n;
+
+ cp = memchr(buf, '\n', n);
+ if (cp)
+ len = cp - buf;
+ if (len == sizeof enabled - 1
+ && strncmp(buf, enabled, sizeof enabled - 1) == 0)
+ device_set_suspend_enable(dev, 1);
+ else if (len == sizeof disabled - 1
+ && strncmp(buf, disabled, sizeof disabled - 1) == 0)
+ device_set_suspend_enable(dev, 0);
+ else
+ return -EINVAL;
+ return n;
+}
+
static ssize_t
wake_show(struct device * dev, struct device_attribute *attr, char * buf)
{
@@ -76,10 +104,11 @@ wake_store(struct device * dev, struct device_attribute *attr,
}
static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store);
-
+static DEVICE_ATTR(suspend, 0644, suspend_show, suspend_store);
static struct attribute * power_attrs[] = {
&dev_attr_wakeup.attr,
+ &dev_attr_suspend.attr,
NULL,
};
static struct attribute_group pm_attr_group = {
diff --git a/include/linux/device.h b/include/linux/device.h
index fdb073b..dc9f242 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -487,6 +487,7 @@ extern struct device *device_find_child(struct device *dev, void *data,
int (*match)(struct device *dev, void *data));
extern int device_rename(struct device *dev, char *new_name);
extern int device_move(struct device *dev, struct device *new_parent);
+extern int device_set_suspend_enable(struct device *dev, int enable);
/*
* Root device objects for grouping under /sys/devices
diff --git a/include/linux/pm.h b/include/linux/pm.h
index de2e0a8..7586a90 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -319,6 +319,9 @@ struct dev_pm_info {
pm_message_t power_state;
unsigned can_wakeup:1;
unsigned should_wakeup:1;
+ unsigned can_suspend:1;
+ unsigned may_suspend:1;
+
enum dpm_state status; /* Owned by the PM core */
#ifdef CONFIG_PM_SLEEP
struct list_head entry;
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