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authorFabrice Gasnier <fabrice.gasnier@st.com>2018-10-01 13:23:56 (GMT)
committerThierry Reding <thierry.reding@gmail.com>2018-10-12 11:51:11 (GMT)
commitc289d6625237aa785b484b4e94c23b3b91ea7e60 (patch)
treec834725cf6230c60ed0919fd37e611f9a6d0243c /drivers/pwm
parentd5a7060022cd443cc6a054bc73383acac6a8f53d (diff)
Revert "pwm: Set class for exported channels in sysfs"
This reverts commit 7e5d1fd75c3dde9fc10c4472b9368089d1b81d00 ("pwm: Set class for exported channels in sysfs") as it causes regression with multiple pwm chip[1], when exporting a pwm channel (echo X > export): - ABI (Documentation/ABI/testing/sysfs-class-pwm) states pwmX should be created in /sys/class/pwm/pwmchipN/pwmX - Reverted patch causes new entry to be also created directly in /sys/class/pwm/pwmX - 1st time, exporting pwmX will create an entry in /sys/class/pwm/pwmX - class attributes are added under pwmX folder, such as export, unexport npwm, symlinks. This is wrong as it belongs to pwmchipN. It may cause bad behavior and report wrong values. - when another export happens on another pwmchip, it can't be created (e.g. -EEXIST). This is causing the issue with multiple pwmchip. Example on stm32 (stm32429i-eval) platform: $ ls /sys/class/pwm pwmchip0 pwmchip4 $ cd /sys/class/pwm/pwmchip0/ $ echo 0 > export $ ls /sys/class/pwm pwm0 pwmchip0 pwmchip4 $ cd /sys/class/pwm/pwmchip4/ $ echo 0 > export sysfs: cannot create duplicate filename '/class/pwm/pwm0' ...Exception stack follows... This is also seen on other platform [2] [1] https://lkml.org/lkml/2018/9/25/713 [2] https://lkml.org/lkml/2018/9/25/447 Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Tested-by: Gottfried Haider <gottfried.haider@gmail.com> Tested-by: Michal Vokáč <michal.vokac@ysoft.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm')
-rw-r--r--drivers/pwm/sysfs.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index 7c71cdb..4726d43 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -263,7 +263,6 @@ static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
export->pwm = pwm;
mutex_init(&export->lock);
- export->child.class = parent->class;
export->child.release = pwm_export_release;
export->child.parent = parent;
export->child.devt = MKDEV(0, 0);

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