pwm: Send a uevent on the pwmchip device upon channel sysfs (un)export (552c02e3) · Commits · 戴 / test

This patch sends a uevent (KOBJ_CHANGE) on the pwmchipN device, everytime a pwmX channel has been exported/unexported via sysfs. This allows udev to implement rules on such events, like: SUBSYSTEM=="pwm*", PROGRAM="/bin/sh -c '\ chown -R root:gpio /sys/class/pwm && chmod -R 770 /sys/class/pwm;\ chown -R root:gpio /sys/devices/platform/soc/*.pwm/pwm/pwmchip* && chmod -R 770 /sys/devices/platform/soc/*.pwm/pwm/pwmchip*\ '" This is a replacement patch for commit ("pwm: Set class for exported channels in sysfs"), see [1]. basic testing: $ udevadm monitor --environment & $ echo 0 > /sys/class/pwm/pwmchip0/export KERNEL[197.321736] change /devices/.../pwm/pwmchip0 (pwm) ACTION=change DEVPATH=/devices/.../pwm/pwmchip0 EXPORT=pwm0 SEQNUM=2045 SUBSYSTEM=pwm [1] https://lkml.org/lkml/2018/9/25/713 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>

drivers/pwm/sysfs.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -249,6 +249,7 @@ static void pwm_export_release(struct device *child)
		static int pwm_export_child(struct device parent, struct pwm_device pwm)
		{
		struct pwm_export *export;
		char *pwm_prop[2];
		int ret;

		if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
		@@ -276,6 +277,10 @@ static int pwm_export_child(struct device parent, struct pwm_device pwm)
		export = NULL;
		return ret;
		}
		pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
		pwm_prop[1] = NULL;
		kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
		kfree(pwm_prop[0]);

		return 0;
		}
		@@ -288,6 +293,7 @@ static int pwm_unexport_match(struct device child, void data)
		static int pwm_unexport_child(struct device parent, struct pwm_device pwm)
		{
		struct device *child;
		char *pwm_prop[2];

		if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
		return -ENODEV;
		@@ -296,6 +302,11 @@ static int pwm_unexport_child(struct device parent, struct pwm_device pwm)
		if (!child)
		return -ENODEV;

		pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
		pwm_prop[1] = NULL;
		kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
		kfree(pwm_prop[0]);

		/* for device_find_child() */
		put_device(child);
		device_unregister(child);

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