From 7fd4edc57bbae9bd62838ebf69d3abfaf8f01173 Mon Sep 17 00:00:00 2001 From: Yoshihiro Shimoda Date: Fri, 31 May 2019 18:55:00 +0900 Subject: 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 Reviewed-by: Geert Uytterhoeven Reviewed-by: Simon Horman [thierry.reding@gmail.com: fix build warnings for !PM] Signed-off-by: Thierry Reding --- drivers/pwm/sysfs.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) (limited to 'drivers/pwm') 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) -- cgit