Hi,
Rafael J. Wysocki wrote:
> On Tuesday 07 April 2009, Michael Trimarchi wrote:
>
>> 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.
>>
>
> Well, can you please tell us a bit about the motivation for this work?
>
> I don't like the approach, but I'd like to know what you're trying to achieve.
>
I works on an hardware that have the gsm connect to wm8753 and the
bluetooth subsystem
too direct connected. So I would like that a phone call for example
remains on during
system suspend. With this approch I can disable suspend of an entire
subtree of device,
that can be used by other hardware component. This change avoid any
specific change to the
driver.
Michael
> Rafael
>
>
>
>> 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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