From 0733424c9ba9f42242409d1ece780777272f7ea1 Mon Sep 17 00:00:00 2001
From: David Hsu <davidhsu@google.com>
Date: Tue, 9 Aug 2016 14:57:46 -0700
Subject: [PATCH] pwm: Unexport children before chip removal

Exported pwm channels aren't removed before the pwmchip and are
leaked. This results in invalid sysfs files. This fix removes
all exported pwm channels before chip removal.

Signed-off-by: David Hsu <davidhsu@google.com>
Fixes: 76abbdde2d95 ("pwm: Add sysfs interface")
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
---
 drivers/pwm/core.c  |  2 ++
 drivers/pwm/sysfs.c | 18 ++++++++++++++++++
 include/linux/pwm.h |  5 +++++
 3 files changed, 25 insertions(+)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 0dbd29e287db..172ef8245811 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -339,6 +339,8 @@ int pwmchip_remove(struct pwm_chip *chip)
 	unsigned int i;
 	int ret = 0;
 
+	pwmchip_sysfs_unexport_children(chip);
+
 	mutex_lock(&pwm_lock);
 
 	for (i = 0; i < chip->npwm; i++) {
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index 18ed725594c3..0296d8178ae2 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -409,6 +409,24 @@ void pwmchip_sysfs_unexport(struct pwm_chip *chip)
 	}
 }
 
+void pwmchip_sysfs_unexport_children(struct pwm_chip *chip)
+{
+	struct device *parent;
+	unsigned int i;
+
+	parent = class_find_device(&pwm_class, NULL, chip,
+				   pwmchip_sysfs_match);
+	if (!parent)
+		return;
+
+	for (i = 0; i < chip->npwm; i++) {
+		struct pwm_device *pwm = &chip->pwms[i];
+
+		if (test_bit(PWMF_EXPORTED, &pwm->flags))
+			pwm_unexport_child(parent, pwm);
+	}
+}
+
 static int __init pwm_sysfs_init(void)
 {
 	return class_register(&pwm_class);
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index f1bbae014889..2c6c5114c089 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -641,6 +641,7 @@ static inline void pwm_remove_table(struct pwm_lookup *table, size_t num)
 #ifdef CONFIG_PWM_SYSFS
 void pwmchip_sysfs_export(struct pwm_chip *chip);
 void pwmchip_sysfs_unexport(struct pwm_chip *chip);
+void pwmchip_sysfs_unexport_children(struct pwm_chip *chip);
 #else
 static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
 {
@@ -649,6 +650,10 @@ static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
 static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip)
 {
 }
+
+static inline void pwmchip_sysfs_unexport_children(struct pwm_chip *chip)
+{
+}
 #endif /* CONFIG_PWM_SYSFS */
 
 #endif /* __LINUX_PWM_H */