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87 lines
2.7 KiB
Diff
87 lines
2.7 KiB
Diff
From 20a5b38305df30e25b4429e0e34e35235dd57228 Mon Sep 17 00:00:00 2001
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From: Fabrice Gasnier <fabrice.gasnier@st.com>
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Date: Mon, 1 Oct 2018 15:23:57 +0200
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Subject: [PATCH] pwm: Send a uevent on the pwmchip device upon channel
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sysfs (un)export
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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commit 552c02e3e7cfe2744b59de285aaea70021ae95c9 upstream.
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This patch sends a uevent (KOBJ_CHANGE) on the pwmchipN device,
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everytime a pwmX channel has been exported/unexported via sysfs. This
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allows udev to implement rules on such events, like:
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SUBSYSTEM=="pwm*", PROGRAM="/bin/sh -c '\
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chown -R root:gpio /sys/class/pwm && chmod -R 770 /sys/class/pwm;\
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chown -R root:gpio
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/sys/devices/platform/soc/*.pwm/pwm/pwmchip* && chmod -R 770
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/sys/devices/platform/soc/*.pwm/pwm/pwmchip*\
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'"
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This is a replacement patch for commit 7e5d1fd75c3d ("pwm: Set class for
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exported channels in sysfs"), see [1].
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basic testing:
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$ udevadm monitor --environment &
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$ echo 0 > /sys/class/pwm/pwmchip0/export
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KERNEL[197.321736] change /devices/.../pwm/pwmchip0 (pwm)
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ACTION=change
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DEVPATH=/devices/.../pwm/pwmchip0
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EXPORT=pwm0
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SEQNUM=2045
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SUBSYSTEM=pwm
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[1] https://lkml.org/lkml/2018/9/25/713
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Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
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Tested-by: Gottfried Haider <gottfried.haider@gmail.com>
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Tested-by: Michal Vokáč <michal.vokac@ysoft.com>
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Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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---
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drivers/pwm/sysfs.c | 11 +++++++++++
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1 file changed, 11 insertions(+)
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--- a/drivers/pwm/sysfs.c
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+++ b/drivers/pwm/sysfs.c
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@@ -249,6 +249,7 @@ static void pwm_export_release(struct de
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static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
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{
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struct pwm_export *export;
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+ char *pwm_prop[2];
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int ret;
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if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
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@@ -276,6 +277,10 @@ static int pwm_export_child(struct devic
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export = NULL;
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return ret;
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}
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+ pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
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+ pwm_prop[1] = NULL;
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+ kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
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+ kfree(pwm_prop[0]);
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return 0;
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}
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@@ -288,6 +293,7 @@ static int pwm_unexport_match(struct dev
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static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
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{
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struct device *child;
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+ char *pwm_prop[2];
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if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
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return -ENODEV;
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@@ -296,6 +302,11 @@ static int pwm_unexport_child(struct dev
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if (!child)
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return -ENODEV;
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+ pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
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+ pwm_prop[1] = NULL;
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+ kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
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+ kfree(pwm_prop[0]);
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+
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/* for device_find_child() */
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put_device(child);
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device_unregister(child);
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