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=-7.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 37DEBC43381 for ; Thu, 21 Feb 2019 19:49:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E869C2081B for ; Thu, 21 Feb 2019 19:49:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="s3kAxYAx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726265AbfBUTtd (ORCPT ); Thu, 21 Feb 2019 14:49:33 -0500 Received: from mail-pg1-f172.google.com ([209.85.215.172]:37631 "EHLO mail-pg1-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726250AbfBUTtd (ORCPT ); Thu, 21 Feb 2019 14:49:33 -0500 Received: by mail-pg1-f172.google.com with SMTP id q206so14256696pgq.4 for ; Thu, 21 Feb 2019 11:49:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=nqoJm7GUlovqo9ROttWj/WT2t2yOXgNTnUnh7Qi+b0o=; b=s3kAxYAxTK3a37Fl02fA5QUy7xUWeHLa+2A8EU1JYDYZwdw0EeZcYViXjnt2nT6pRd QGWmW1JAYP+9/v56XuRGKgkE4RrWC86hYzXmPPpK8xQXZdbKE9Rw9TyMOAcLdBeD0bPB gWOKWSag3/Dcd+fgX4tkvc8LvaX8+DPzhdHq+kLQj2GDDBaxZF4BKd5nhqyDZ6o0DiIs OeCuutjFJ+DMx237AsjVH8aDpbKGG5LpNi2C/rn7qFV2VBfTVUa4g7Tq1vKYEqj593XV MAlPxfTIXJqW9oIURGKoU1xYZcjAcANQ+zos0AYjjOXkBGC0cy8XBMPIclTtpJGpEq6Q T9ew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=nqoJm7GUlovqo9ROttWj/WT2t2yOXgNTnUnh7Qi+b0o=; b=pkF7bcGvzyxjywyR3O/uwtIXx+MMbefopzFmseHzWF2tEptzrF9Z9l143+S/YbBteq GJxu/9lPqNQnXV2VXybmNJ56W033pSCwClv9y8RempVWSM24QTu83I3hOlFYvkgz80Im AS5SpFdC2C18Ar/YCoVye4HFPKpsW1ixDkilQdF0mZAXTx/z374JsXz+6gG99Z2bjQ7l 22THOzHekaL/OscpchOUsNA/M4VV85Ehm/aO2h9dM8KPTXt9TPswQD81sLK5pOxijdZL Ad54xZFVU/FQ5XSnf7/mdwR4n4lNIDH7U0oZUL6NahuuSaaSURh4XE3/GRj4eZmbE+Vu pXCg== X-Gm-Message-State: AHQUAuZBT49J2S6MLXriPFflVhhFa8pPbZrV9URZk/7/lga2133MV5wh 5cB3YRyASUWgn8wsy3a5ZQc= X-Google-Smtp-Source: AHgI3IZNvXnY4iI6z1oftLCi70LeIOVs83z8DnRCCS2weUPM+G+PH8/y9rUPvKZ2OKiakOH1lvm0pw== X-Received: by 2002:a62:7592:: with SMTP id q140mr233639pfc.164.1550778572196; Thu, 21 Feb 2019 11:49:32 -0800 (PST) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id r80sm35715101pfa.111.2019.02.21.11.49.30 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 21 Feb 2019 11:49:30 -0800 (PST) Date: Thu, 21 Feb 2019 11:49:29 -0800 From: Guenter Roeck To: Vinay Simha B N Cc: jdelvare@suse.com, linux-hwmon@vger.kernel.org Subject: Re: tmp102 hwmon accessing temp1_input, max, max_hyst Message-ID: <20190221194929.GA676@roeck-us.net> References: <20190221175511.GA22715@roeck-us.net> <20190221184805.GC22715@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-hwmon-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org On Fri, Feb 22, 2019 at 12:32:08AM +0530, Vinay Simha B N wrote: > On Fri, Feb 22, 2019 at 12:18 AM Guenter Roeck wrote: > > > > On Thu, Feb 21, 2019 at 11:46:32PM +0530, Vinay Simha B N wrote: > > > guenter, > > > > > > i want to use these three tmp102 temp1_input, max and max_hys in > > > dsi2hdmi(adv7533) driver to enable or disabled based on temperature > > > range. > > > > > > https://github.com/vinaysimha/kernel-msm/commit/8ee2b9104fa56765320d4846086d91b8271f5609 > > > > > > dsi2hdmi operating temperature range is -10 to 85 deg C, we will > > > enable dsi2hdmi only when temperate in operating range otherwise will > > > disable the chip. > > > > > Do you envision a system utilizing this chip that would have an operating range > > outsize -10 .. +85 degrees C ? That seems to be quite unlikely. > this system sits in a place below this temperature range, cpu can > handle upto -30, but the adv7535(dsi2hdmi) operating range -10 to +85, > so we want the system to be on and disable and enable display based on > temp range. > > > > Your solution will only work for a system with exactly one tempperature sensor; > > otherwise there is no guarantee that the sensor will be instantiated as hwmon1 > we do have two temperature sensor, currently i had used hwmon1 for testing, > i have to read hwmon1 otherwise interrupt will not get cleared. > thought to have polling method also, since in this code reading from > userspace is not feasible, is it possible to optimize, any suggestion? > either i need to have global variable declared in adv7511_drv.c and > export it to tmp102.c driver . please suggest You might want to consider attaching the tmp102 to a thermal zone, and then use thermal_zone_get_temp() to read the temperature. > > > > Either case, a decison like this would not only apply to a single chip, > > but to other chips in the system. It might be in the scope of power > > or thermal management, though it seems to me that it might make more > > sense to control it from user space. > > > > Overall, with the above in mind, I don't think a hwmon specific solution > > would make sense. If a solution is really warranted in the first place > > (I really wonder about that operating range), it should be implemented > > as generic solution which applies to the rest of the system as well. > > > > There are some pieces which should be implemented in the hwmon driver - > > for example, it looks like your code implements interrupt handling for > > the tmp102. That should be handled in the tmp102 driver, which would > > then read the alert bit and report the status as temp1_alarm. > initially i had implemented irq in tmp102.c , but how to inform this > information to dsi2hdmi(adv7511_drv.c) > any references how temp1_alarm is used. This would require some work, since the infrastructure does not currently support handling thermal alarms. In a nutshell, - the tmp102 driver would implement an interrupt handler - the interrupt handler would notify the hwmon core that an interrupt was observed. This notification callback would have to be implemented. It would notify userspace using sysfs_notify() and possibly with a udev event, and it would notify the thermal core by calling thermal_zone_device_update(). I don't know how the thermal core would then notify the dsi2hdmi driver. Guenter > > > > Thanks, > > Guenter > > > > > > > > On Thu, Feb 21, 2019 at 11:25 PM Guenter Roeck wrote: > > > > > > > > On Thu, Feb 21, 2019 at 08:21:09PM +0530, Vinay Simha B N wrote: > > > > > hi, > > > > > > > > > > could you please suggest, how to export_symbol the tmp102 temp1_input, max > > > > > and max_hyst values to another kernel driver? > > > > > > > > > > We can acess the values > > > > > from filp_open("/sys/class/hwmon/hwmon1/temp1_input", O_RDONLY, 0); in > > > > > kernel space, but is there better apporach to access the values in the > > > > > kernel space. > > > > > > > > > There is no in-kernel API to do that, and I do not immediately see > > > > the purpose. Either case, accessing the sysfs attribute directly is > > > > as wrong as it can get, if for nothing else since there is no guarantee > > > > that this will always be the hwmon1 device. > > > > > > > > Can you explain what you are trying to do ? > > > > > > > > Thanks, > > > > Guenter > > > > > > > > > > > > -- > > > regards, > > > vinaysimha > > > > -- > regards, > vinaysimha