From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F5A2C43143 for ; Mon, 1 Oct 2018 13:24:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D2B5F208E7 for ; Mon, 1 Oct 2018 13:24:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D2B5F208E7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=st.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729430AbeJAUC1 (ORCPT ); Mon, 1 Oct 2018 16:02:27 -0400 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:30490 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729286AbeJAUC1 (ORCPT ); Mon, 1 Oct 2018 16:02:27 -0400 Received: from pps.filterd (m0046660.ppops.net [127.0.0.1]) by mx08-.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id w91DOCIN031562; Mon, 1 Oct 2018 15:24:12 +0200 Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx08-00178001.pphosted.com with ESMTP id 2msxh6bevp-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT); Mon, 01 Oct 2018 15:24:12 +0200 Received: from zeta.dmz-eu.st.com (zeta.dmz-eu.st.com [164.129.230.9]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id D4C3231; Mon, 1 Oct 2018 13:24:10 +0000 (GMT) Received: from Webmail-eu.st.com (sfhdag5node3.st.com [10.75.127.15]) by zeta.dmz-eu.st.com (STMicroelectronics) with ESMTP id A7237465E; Mon, 1 Oct 2018 13:24:10 +0000 (GMT) Received: from localhost (10.75.127.45) by SFHDAG5NODE3.st.com (10.75.127.15) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Mon, 1 Oct 2018 15:24:10 +0200 From: Fabrice Gasnier To: , CC: , , , , , , , , , , , Subject: [PATCH v2 0/2] pwm: sysfs: fix exporting PWM channel Date: Mon, 1 Oct 2018 15:23:55 +0200 Message-ID: <1538400237-28766-1-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.75.127.45] X-ClientProxiedBy: SFHDAG5NODE1.st.com (10.75.127.13) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-10-01_08:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since commit 7e5d1fd75c3d ("pwm: Set class for exported channels in sysfs") - it's not possible to export more than one PWM channel - ABI has changed, as a side effect. It may cause bad behavior as pwmchip attributes are wrongly added to pwm channels and report wrong values. See [1] and [2]. One purpose of the original patch is to send uevents to udev, when exporting a PWM channel through the sysfs. This series: - Reverts the original patch. - Proposes a new way to send notifications to be used by udev rules. - With this series: $ echo 0 > /sys/class/pwm/pwmchip0/export $ ls /sys/class/pwm pwmchip0 pwmchip4 $ ls /sys/class/pwm/pwmchip0/pwm0/ capture enable polarity uevent duty_cycle period power - Without this series: $ echo 0 > /sys/class/pwm/pwmchip0/export $ ls /sys/class/pwm pwm0 pwmchip0 pwmchip4 $ ls /sys/class/pwm/pwmchip0/pwm0/ capture duty_cycle export period power uevent device enable npwm polarity subsystem unexport - Backtrace when exporting a 2nd channel (0) on a separate pwmchip device: $ echo 0 > /sys/class/pwm/pwmchip4/export [ 95.286558] sysfs: cannot create duplicate filename '/class/pwm/pwm0' [ 95.293630] CPU: 0 PID: 54 Comm: sh Not tainted 4.19.0-rc6-00013-g00b49b0 #151 [ 95.301344] Hardware name: STM32 (Device Tree Support) [ 95.306833] [<0000c155>] (unwind_backtrace) from [<0000b273>] (show_stack+0xb/0xc) [ 95.315136] [<0000b273>] (show_stack) from [<00092455>] (sysfs_warn_dup+0x31/0x48) [ 95.323247] [<00092455>] (sysfs_warn_dup) from [<00092635>] (sysfs_do_create_link_sd+0x75/0x88) [ 95.332539] [<00092635>] (sysfs_do_create_link_sd) from [<00125823>] (device_add+0x133/0x3b0) [ 95.341694] [<00125823>] (device_add) from [<001059ed>] (export_store+0xb5/0x12c) [ 95.349761] [<001059ed>] (export_store) from [<00091911>] (kernfs_fop_write+0x87/0xda) [ 95.358150] [<00091911>] (kernfs_fop_write) from [<0005beb1>] (__vfs_write+0x1d/0xe0) [ 95.366295] [<0005beb1>] (__vfs_write) from [<0005bfe7>] (vfs_write+0x4f/0x7c) [ 95.374053] [<0005bfe7>] (vfs_write) from [<0005c0bf>] (ksys_write+0x33/0x70) [ 95.381708] [<0005c0bf>] (ksys_write) from [<00009001>] (ret_fast_syscall+0x1/0x58) [ 95.389682] Exception stack(0x01bcffa8 to 0x01bcfff0) [ 95.394946] ffa0: 00000000 00c4883c 00000001 00c4e590 00000002 00000004 [ 95.403639] ffc0: 00000000 00c4883c 00c4cbe8 00000004 00000002 00000020 00000000 00c4d008 [ 95.412223] ffe0: 00c29151 00c4cbe8 00c17833 00c13c0c -sh: write error: File exists [1] https://lkml.org/lkml/2018/9/25/713 [2] https://lkml.org/lkml/2018/9/25/447 --- Changes in v2: - update revert commit message - new patch 2/2 to propose uevent notification (change) on pwmchip Fabrice Gasnier (2): Revert "pwm: Set class for exported channels in sysfs" pwm: send a uevent on the pwmchip device upon channel sysfs (un)export drivers/pwm/sysfs.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) -- 1.9.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fabrice Gasnier Subject: [PATCH v2 0/2] pwm: sysfs: fix exporting PWM channel Date: Mon, 1 Oct 2018 15:23:55 +0200 Message-ID: <1538400237-28766-1-git-send-email-fabrice.gasnier@st.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Sender: linux-kernel-owner@vger.kernel.org To: thierry.reding@gmail.com, gottfried.haider@gmail.com Cc: stefan.wahren@i2se.com, hsweeten@visionengravers.com, loic.pallardy@st.com, broonie@kernel.org, fabrice.gasnier@st.com, gohai@sukzessiv.net, michal.vokac@ysoft.com, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org List-Id: linux-pwm@vger.kernel.org Since commit 7e5d1fd75c3d ("pwm: Set class for exported channels in sysfs") - it's not possible to export more than one PWM channel - ABI has changed, as a side effect. It may cause bad behavior as pwmchip attributes are wrongly added to pwm channels and report wrong values. See [1] and [2]. One purpose of the original patch is to send uevents to udev, when exporting a PWM channel through the sysfs. This series: - Reverts the original patch. - Proposes a new way to send notifications to be used by udev rules. - With this series: $ echo 0 > /sys/class/pwm/pwmchip0/export $ ls /sys/class/pwm pwmchip0 pwmchip4 $ ls /sys/class/pwm/pwmchip0/pwm0/ capture enable polarity uevent duty_cycle period power - Without this series: $ echo 0 > /sys/class/pwm/pwmchip0/export $ ls /sys/class/pwm pwm0 pwmchip0 pwmchip4 $ ls /sys/class/pwm/pwmchip0/pwm0/ capture duty_cycle export period power uevent device enable npwm polarity subsystem unexport - Backtrace when exporting a 2nd channel (0) on a separate pwmchip device: $ echo 0 > /sys/class/pwm/pwmchip4/export [ 95.286558] sysfs: cannot create duplicate filename '/class/pwm/pwm0' [ 95.293630] CPU: 0 PID: 54 Comm: sh Not tainted 4.19.0-rc6-00013-g00b49b0 #151 [ 95.301344] Hardware name: STM32 (Device Tree Support) [ 95.306833] [<0000c155>] (unwind_backtrace) from [<0000b273>] (show_stack+0xb/0xc) [ 95.315136] [<0000b273>] (show_stack) from [<00092455>] (sysfs_warn_dup+0x31/0x48) [ 95.323247] [<00092455>] (sysfs_warn_dup) from [<00092635>] (sysfs_do_create_link_sd+0x75/0x88) [ 95.332539] [<00092635>] (sysfs_do_create_link_sd) from [<00125823>] (device_add+0x133/0x3b0) [ 95.341694] [<00125823>] (device_add) from [<001059ed>] (export_store+0xb5/0x12c) [ 95.349761] [<001059ed>] (export_store) from [<00091911>] (kernfs_fop_write+0x87/0xda) [ 95.358150] [<00091911>] (kernfs_fop_write) from [<0005beb1>] (__vfs_write+0x1d/0xe0) [ 95.366295] [<0005beb1>] (__vfs_write) from [<0005bfe7>] (vfs_write+0x4f/0x7c) [ 95.374053] [<0005bfe7>] (vfs_write) from [<0005c0bf>] (ksys_write+0x33/0x70) [ 95.381708] [<0005c0bf>] (ksys_write) from [<00009001>] (ret_fast_syscall+0x1/0x58) [ 95.389682] Exception stack(0x01bcffa8 to 0x01bcfff0) [ 95.394946] ffa0: 00000000 00c4883c 00000001 00c4e590 00000002 00000004 [ 95.403639] ffc0: 00000000 00c4883c 00c4cbe8 00000004 00000002 00000020 00000000 00c4d008 [ 95.412223] ffe0: 00c29151 00c4cbe8 00c17833 00c13c0c -sh: write error: File exists [1] https://lkml.org/lkml/2018/9/25/713 [2] https://lkml.org/lkml/2018/9/25/447 --- Changes in v2: - update revert commit message - new patch 2/2 to propose uevent notification (change) on pwmchip Fabrice Gasnier (2): Revert "pwm: Set class for exported channels in sysfs" pwm: send a uevent on the pwmchip device upon channel sysfs (un)export drivers/pwm/sysfs.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) -- 1.9.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: fabrice.gasnier@st.com (Fabrice Gasnier) Date: Mon, 1 Oct 2018 15:23:55 +0200 Subject: [PATCH v2 0/2] pwm: sysfs: fix exporting PWM channel Message-ID: <1538400237-28766-1-git-send-email-fabrice.gasnier@st.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Since commit 7e5d1fd75c3d ("pwm: Set class for exported channels in sysfs") - it's not possible to export more than one PWM channel - ABI has changed, as a side effect. It may cause bad behavior as pwmchip attributes are wrongly added to pwm channels and report wrong values. See [1] and [2]. One purpose of the original patch is to send uevents to udev, when exporting a PWM channel through the sysfs. This series: - Reverts the original patch. - Proposes a new way to send notifications to be used by udev rules. - With this series: $ echo 0 > /sys/class/pwm/pwmchip0/export $ ls /sys/class/pwm pwmchip0 pwmchip4 $ ls /sys/class/pwm/pwmchip0/pwm0/ capture enable polarity uevent duty_cycle period power - Without this series: $ echo 0 > /sys/class/pwm/pwmchip0/export $ ls /sys/class/pwm pwm0 pwmchip0 pwmchip4 $ ls /sys/class/pwm/pwmchip0/pwm0/ capture duty_cycle export period power uevent device enable npwm polarity subsystem unexport - Backtrace when exporting a 2nd channel (0) on a separate pwmchip device: $ echo 0 > /sys/class/pwm/pwmchip4/export [ 95.286558] sysfs: cannot create duplicate filename '/class/pwm/pwm0' [ 95.293630] CPU: 0 PID: 54 Comm: sh Not tainted 4.19.0-rc6-00013-g00b49b0 #151 [ 95.301344] Hardware name: STM32 (Device Tree Support) [ 95.306833] [<0000c155>] (unwind_backtrace) from [<0000b273>] (show_stack+0xb/0xc) [ 95.315136] [<0000b273>] (show_stack) from [<00092455>] (sysfs_warn_dup+0x31/0x48) [ 95.323247] [<00092455>] (sysfs_warn_dup) from [<00092635>] (sysfs_do_create_link_sd+0x75/0x88) [ 95.332539] [<00092635>] (sysfs_do_create_link_sd) from [<00125823>] (device_add+0x133/0x3b0) [ 95.341694] [<00125823>] (device_add) from [<001059ed>] (export_store+0xb5/0x12c) [ 95.349761] [<001059ed>] (export_store) from [<00091911>] (kernfs_fop_write+0x87/0xda) [ 95.358150] [<00091911>] (kernfs_fop_write) from [<0005beb1>] (__vfs_write+0x1d/0xe0) [ 95.366295] [<0005beb1>] (__vfs_write) from [<0005bfe7>] (vfs_write+0x4f/0x7c) [ 95.374053] [<0005bfe7>] (vfs_write) from [<0005c0bf>] (ksys_write+0x33/0x70) [ 95.381708] [<0005c0bf>] (ksys_write) from [<00009001>] (ret_fast_syscall+0x1/0x58) [ 95.389682] Exception stack(0x01bcffa8 to 0x01bcfff0) [ 95.394946] ffa0: 00000000 00c4883c 00000001 00c4e590 00000002 00000004 [ 95.403639] ffc0: 00000000 00c4883c 00c4cbe8 00000004 00000002 00000020 00000000 00c4d008 [ 95.412223] ffe0: 00c29151 00c4cbe8 00c17833 00c13c0c -sh: write error: File exists [1] https://lkml.org/lkml/2018/9/25/713 [2] https://lkml.org/lkml/2018/9/25/447 --- Changes in v2: - update revert commit message - new patch 2/2 to propose uevent notification (change) on pwmchip Fabrice Gasnier (2): Revert "pwm: Set class for exported channels in sysfs" pwm: send a uevent on the pwmchip device upon channel sysfs (un)export drivers/pwm/sysfs.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) -- 1.9.1