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authorYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>2019-05-31 18:55:00 +0900
committerThierry Reding <thierry.reding@gmail.com>2019-06-26 11:39:11 +0200
commit7fd4edc57bbae9bd62838ebf69d3abfaf8f01173 (patch)
tree151993e99581fa4e0825d801488f832096ce3608
parent321a7cea973b4f63bb7e3baaea8428dfb8b424a9 (diff)
downloadlinux-7fd4edc57bbae9bd62838ebf69d3abfaf8f01173.tar.bz2
pwm: sysfs: Add suspend/resume support
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@renesas.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Simon Horman <horms+renesas@verge.net.au> [thierry.reding@gmail.com: fix build warnings for !PM] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
-rw-r--r--drivers/pwm/sysfs.c102
1 files changed, 102 insertions, 0 deletions
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index 719f8fada0a7..8158a434f7b8 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -27,6 +27,7 @@ struct pwm_export {
struct device child;
struct pwm_device *pwm;
struct mutex lock;
+ struct pwm_state suspend;
};
static struct pwm_export *child_to_pwm_export(struct device *child)
@@ -381,10 +382,111 @@ static struct attribute *pwm_chip_attrs[] = {
};
ATTRIBUTE_GROUPS(pwm_chip);
+/* takes export->lock on success */
+static struct pwm_export *pwm_class_get_state(struct device *parent,
+ struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct device *child;
+ struct pwm_export *export;
+
+ if (!test_bit(PWMF_EXPORTED, &pwm->flags))
+ return NULL;
+
+ child = device_find_child(parent, pwm, pwm_unexport_match);
+ if (!child)
+ return NULL;
+
+ export = child_to_pwm_export(child);
+ put_device(child); /* for device_find_child() */
+
+ mutex_lock(&export->lock);
+ pwm_get_state(pwm, state);
+
+ return export;
+}
+
+static int pwm_class_apply_state(struct pwm_export *export,
+ struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ int ret = pwm_apply_state(pwm, state);
+
+ /* release lock taken in pwm_class_get_state */
+ mutex_unlock(&export->lock);
+
+ return ret;
+}
+
+static int pwm_class_resume_npwm(struct device *parent, unsigned int npwm)
+{
+ struct pwm_chip *chip = dev_get_drvdata(parent);
+ unsigned int i;
+ int ret = 0;
+
+ for (i = 0; i < npwm; i++) {
+ struct pwm_device *pwm = &chip->pwms[i];
+ struct pwm_state state;
+ struct pwm_export *export;
+
+ export = pwm_class_get_state(parent, pwm, &state);
+ if (!export)
+ continue;
+
+ state.enabled = export->suspend.enabled;
+ ret = pwm_class_apply_state(export, pwm, &state);
+ if (ret < 0)
+ break;
+ }
+
+ return ret;
+}
+
+static int __maybe_unused pwm_class_suspend(struct device *parent)
+{
+ 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 pwm_state state;
+ struct pwm_export *export;
+
+ export = pwm_class_get_state(parent, pwm, &state);
+ if (!export)
+ continue;
+
+ export->suspend = state;
+ state.enabled = false;
+ ret = pwm_class_apply_state(export, pwm, &state);
+ if (ret < 0) {
+ /*
+ * roll back the PWM devices that were disabled by
+ * this suspend function.
+ */
+ pwm_class_resume_npwm(parent, i);
+ break;
+ }
+ }
+
+ return ret;
+}
+
+static int __maybe_unused pwm_class_resume(struct device *parent)
+{
+ struct pwm_chip *chip = dev_get_drvdata(parent);
+
+ return pwm_class_resume_npwm(parent, chip->npwm);
+}
+
+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)