From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philip Munts Subject: No hotplug event for PCA9685 PWM output device Date: Wed, 12 Apr 2017 14:09:35 +0200 Message-ID: <6ecbfb82-ea0f-f403-7655-bb185ba286d3@munts.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from p3plsmtpa12-06.prod.phx3.secureserver.net ([68.178.252.235]:49038 "EHLO p3plsmtpa12-06.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753489AbdDLMKM (ORCPT ); Wed, 12 Apr 2017 08:10:12 -0400 Sender: linux-pwm-owner@vger.kernel.org List-Id: linux-pwm@vger.kernel.org To: linux-pwm@vger.kernel.org I am using a PCA9685 I2C PWM controller on a Raspberry Pi 2. When I instantiate the PCA9685 device with "echo pca9685 0x40 >new_device" in the I2C bus device directory, I get a hotplug event for pwmchip0, as expected. When I manually initiate a hotplug event with "echo add >uevent" from the pwmchip0 device directory, I get another hotplug event for pwmchip0, also as expected. However, when I create a PWM output device with "echo 0 >export" from the pwmchip0 device directory, the PWM output device subdirectory pwm0 is created, including the uevent file, but no hotplug event is generated for pwm0. Furthermore, when I attempt to manually initiate a hotplug event for pwm0 by running "echo add >uevent" from the pwm0 subdirectory, no hotplug event is generated. I am using a custom 4.9.21 kernel. I have reported this at bugzilla.kernel.org: #195335. Philip Munts phil@munts.net