From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x2268niIaiK1z3kwL50++1PEbUBXmuGoH2tKAJxP2PVRFo8cPRK/cy1MTHK7x5XXdXirN7dTx ARC-Seal: i=1; a=rsa-sha256; t=1517399488; cv=none; d=google.com; s=arc-20160816; b=ebMYctYgqXs5AQvwzn9+AV/E/xNBH3gJZEmGUvmlOemL8iYZ2Kck7dDIz9j3m59THg UB97pzAY5w6RxIn/BLRZqfzZwh2EEQM5o0y4onmbF5DtywLQvzRBQh4Cd6JLXDsRWnFp SDfwK7fucNhyyvT9DLi5pOv2s1qhlJavoc9hxudP+SiBUSP/xRjyjh6CoAG/ehxNlJnF BN4ztwGfVmNHCxb7Ny6VegAN6z+ILAakodX5qdZe96OxOElKQBPT7t0d+ILNAQNVk9QK wtA3HmLC9fUF2WgjpcSEGUYU4I/dqXdLfq2PuLmvLCc/KRk0dfOl6OiNG7bu4NhNpQMO tmFQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:message-id:date:references:organization:in-reply-to :subject:cc:to:from:arc-authentication-results; bh=sDbVNVIZwNQ7pEdMofMPrY6f8cgJci8xslhdeQ6wfdE=; b=rp+LESXy+hsLzGw42SIQaJjjurPOwM2JkXFMLCML/zaITLhNn8e7kDiLX3jjWYgkaU WvOl8rbn8WT5UY+OIv8JOOCfopRzGF2M+Qh20gIaGAnDPDdAZr12XJu9ESIMhJVrkPND A7giCP3LtakxmU3L5EetGKwUjWCi/Vz6IbCV/HOcbPS0hqcKImgiqbp0UhUfMWKqU0gH j9uq8HXAEsO3RzSjLhUURNUNkxx9FzToVlaWtua98ywSS9UoAFXDfRbMcKFM3a7lC0Hl HNgZGFJHhpE4/vk1GAPbF4uuGt9tczul9WOcp/TzzF/L4t+yc9K1N3l/vrfJI4YfWtY5 FSqA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of jani.nikula@intel.com designates 134.134.136.24 as permitted sender) smtp.mailfrom=jani.nikula@intel.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of jani.nikula@intel.com designates 134.134.136.24 as permitted sender) smtp.mailfrom=jani.nikula@intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,439,1511856000"; d="scan'208";a="26917323" From: Jani Nikula To: Daniel Thompson , Aishwarya Pant Cc: Milo Kim , linux-fbdev@vger.kernel.org, Bartlomiej Zolnierkiewicz , Jingoo Han , Jonathan Corbet , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Julia Lawall , Greg KH , Lee Jones Subject: Re: [PATCH 1/5] backlight: lp8788: document sysfs attributes In-Reply-To: <20180131110727.rmmwyqzwozwhda6z@oak.lan> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <6523e26889d3dd65e90ea27c0d302a95aeb9da8b.1516978005.git.aishpant@gmail.com> <20180131110727.rmmwyqzwozwhda6z@oak.lan> Date: Wed, 31 Jan 2018 13:51:21 +0200 Message-ID: <878tceckli.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1590666949916676069?= X-GMAIL-MSGID: =?utf-8?q?1591108686008944068?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Wed, 31 Jan 2018, Daniel Thompson wrote: > On Fri, Jan 26, 2018 at 08:20:08PM +0530, Aishwarya Pant wrote: >> Add documentation for sysfs interfaces of lp8788 backlight driver by >> looking through the code and the git commit history. >> >> Signed-off-by: Aishwarya Pant >> --- >> Documentation/ABI/testing/sysfs-class-backlight-lp8788 | 10 ++++++++++ >> 1 file changed, 10 insertions(+) >> create mode 100644 Documentation/ABI/testing/sysfs-class-backlight-lp8788 >> >> diff --git a/Documentation/ABI/testing/sysfs-class-backlight-lp8788 b/Documentation/ABI/testing/sysfs-class-backlight-lp8788 >> new file mode 100644 >> index 000000000000..c0e565c8d63d >> --- /dev/null >> +++ b/Documentation/ABI/testing/sysfs-class-backlight-lp8788 >> @@ -0,0 +1,10 @@ >> +sysfs interface for Texas Instruments lp8788 mfd backlight driver >> +----------------------------------------------------------------- >> + >> +What: /sys/class/backlight//bl_ctl_mode >> +Date: Feb, 2013 >> +KernelVersion: v3.10 >> +Contact: Milo Kim >> +Description: >> + (RO) Displays whether the brightness is controlled by the PWM >> + input("PWM based") or the I2C register("Register based"). > > I rather dislike drivers with this type of "bonus" sysfs controls. I'm > struggling to come up with any reason why the userspace would want to > read this control (and I think bl_ctl_mode gets the fewest hits after > searching with google hits of any search I've tried) . It looks to me > like this is debug information that should never have gone into sysfs > at all. Agreed. I think the same holds for the other extra sysfs attributes. At worst, having these prevents the backlight class from adding the names later on, which is just backwards. BR, Jani. > > So I think this is either something that should go directly into > ABI/obsolete (with a fairly short expiry time) or perhaps simply > remove the property entirely. > > > Daniel. > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Jani Nikula, Intel Open Source Technology Center