According to the Documentation/pwm.txt, all PWM consumers should have
power management. Since this sysfs interface is one of consumers so that
this patch adds suspend/resume support.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
---
drivers/pwm/sysfs.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index 7eb4a13..72dafdd 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -18,6 +18,7 @@ struct pwm_export {
struct device child;
struct pwm_device *pwm;
struct mutex lock;
+ bool enabled_in_suspend;
};
static struct pwm_export *child_to_pwm_export(struct device *child)
@@ -372,10 +373,73 @@ static struct attribute *pwm_chip_attrs[] = {
};
ATTRIBUTE_GROUPS(pwm_chip);
+static int pwm_class_suspend_resume(struct device *parent, bool suspend)
+{
+ struct pwm_chip *chip = dev_get_drvdata(parent);
+ unsigned int i;
+ int ret = 0;
+
+ for (i = 0; i < chip->npwm; i++) {
+ struct pwm_device *pwm = &chip->pwms[i];
+ struct device *child;
+ struct pwm_export *export;
+ struct pwm_state state;
+
+ if (!test_bit(PWMF_EXPORTED, &pwm->flags))
+ continue;
+
+ child = device_find_child(parent, pwm, pwm_unexport_match);
+ if (!child)
+ goto rollback;
+
+ export = child_to_pwm_export(child);
+ put_device(child); /* for device_find_child() */
+ if (!export)
+ goto rollback;
+
+ mutex_lock(&export->lock);
+ pwm_get_state(pwm, &state);
+ if (suspend) {
+ if (state.enabled)
+ export->enabled_in_suspend = true;
+ state.enabled = false;
+ } else if (export->enabled_in_suspend) {
+ state.enabled = true;
+ export->enabled_in_suspend = false;
+ }
+ ret = pwm_apply_state(pwm, &state);
+ mutex_unlock(&export->lock);
+ if (ret < 0)
+ goto rollback;
+ }
+
+ return ret;
+
+rollback:
+ /* roll back only when suspend */
+ if (suspend)
+ pwm_class_suspend_resume(parent, false);
+
+ return ret;
+}
+
+static int pwm_class_suspend(struct device *parent)
+{
+ return pwm_class_suspend_resume(parent, true);
+}
+
+static int pwm_class_resume(struct device *parent)
+{
+ return pwm_class_suspend_resume(parent, false);
+}
+
+static SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);
+
static struct class pwm_class = {
.name = "pwm",
.owner = THIS_MODULE,
.dev_groups = pwm_chip_groups,
+ .pm = &pwm_class_pm_ops,
};
static int pwmchip_sysfs_match(struct device *parent, const void *data)
--
2.7.4
