From patchwork Mon Apr 11 13:41:41 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laxman Dewangan X-Patchwork-Id: 8802271 X-Patchwork-Delegate: eduardo.valentin@ti.com Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 3062E9F3D1 for ; Mon, 11 Apr 2016 13:55:13 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 41A80202B8 for ; Mon, 11 Apr 2016 13:55:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2DB30202AE for ; Mon, 11 Apr 2016 13:55:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933450AbcDKNyy (ORCPT ); Mon, 11 Apr 2016 09:54:54 -0400 Received: from hqemgate16.nvidia.com ([216.228.121.65]:12918 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754568AbcDKNxQ (ORCPT ); Mon, 11 Apr 2016 09:53:16 -0400 Received: from hqnvupgp07.nvidia.com (Not Verified[216.228.121.13]) by hqemgate16.nvidia.com id ; Mon, 11 Apr 2016 06:53:03 -0700 Received: from HQHUB102.nvidia.com ([172.20.12.94]) by hqnvupgp07.nvidia.com (PGP Universal service); Mon, 11 Apr 2016 06:50:46 -0700 X-PGP-Universal: processed; by hqnvupgp07.nvidia.com on Mon, 11 Apr 2016 06:50:46 -0700 Received: from hqemhub02.nvidia.com (172.20.150.31) by HQHUB102.nvidia.com (172.20.187.25) with Microsoft SMTP Server (TLS) id 8.3.406.0; Mon, 11 Apr 2016 06:53:09 -0700 Received: from ldewanganubuntu-System-Product-Name.nvidia.com (172.20.144.16) by hqemhub02.nvidia.com (172.20.150.31) with Microsoft SMTP Server (TLS) id 8.3.406.0; Mon, 11 Apr 2016 06:53:08 -0700 From: Laxman Dewangan To: , , , , , , CC: , , , , Laxman Dewangan Subject: [PATCH V2 1/2] thermal: generic-adc: Add DT binding for ADC based thermal sensor Date: Mon, 11 Apr 2016 19:11:41 +0530 Message-ID: <1460382102-27755-1-git-send-email-ldewangan@nvidia.com> X-Mailer: git-send-email 2.1.4 MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Sometimes, thermal sensors like NCT thermistors are connected to the ADC channel. The temperature is read by reading the voltage across the sensor resistance via ADC and referring the lookup table for ADC value to temperature. Add DT binding doc for the ADC based thermal sensor driver to detail the DT property and provide the example for how to use it. Signed-off-by: Laxman Dewangan --- Changes from V1: - Make the lookup table to two dimensional instead of single array of linear step of temperature. - Remove detailing of IIO frameowrk and drivers. - Added proper braces, indenting and labels. .../bindings/thermal/thermal-generic-adc.txt | 86 ++++++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt diff --git a/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt b/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt new file mode 100644 index 0000000..c5c2e5b --- /dev/null +++ b/Documentation/devicetree/bindings/thermal/thermal-generic-adc.txt @@ -0,0 +1,86 @@ +General Purpose Analog To Digital Converter (ADC) based thermal sensor. + +On some of platforms, thermal sensor like thermistors are connected to +one of ADC channel and sensor resistance is read via voltage across the +sensor resistor. The voltage read across the sensor is mapped to +temperature using voltage-temperature lookup table. + +Required properties: +=================== +- compatible: Must be "generic-adc-thermal". +- temperature-lookup-table: Two dimensional array of Integer; lookup table + to map the relation between ADC value and + temperature. When ADC is read, the value is + looked up on the table to get the equivalent + temperature. +- #thermal-sensor-cells: Should be 1. See ./thermal.txt for a description + of this property. + +Example : +#include + +i2c@7000c400 { + ads1015: ads1015@4a { + reg = <0x4a>; + compatible = "ads1015"; + sampling-frequency = <3300>; + #io-channel-cells = <1>; + }; +}; + +tboard_thermistor: thermal-sensor@1 { + compatible = "generic-adc-thermal"; + #thermal-sensor-cells = <0>; + io-channels = <&ads1015 1>; + io-channel-names = "sensor-channel"; + temperature-lookup-table = < (-40000) 2578 + (-39000) 2577 + (-38000) 2576 + (-37000) 2575 + (-36000) 2574 + (-35000) 2573 + (-34000) 2572 + (-33000) 2571 + (-32000) 2569 + (-31000) 2568 + (-30000) 2567 + :::::::::: + 118000 254 + 119000 247 + 120000 240 + 121000 233 + 122000 226 + 123000 220 + 124000 214 + 125000 208>; +}; + +dummy_cool_dev: dummy-cool-dev { + compatible = "dummy-cooling-dev"; + #cooling-cells = <2>; /* min followed by max */ +}; + +thermal-zones { + Tboard { + polling-delay = <15000>; /* milliseconds */ + polling-delay-passive = <0>; /* milliseconds */ + thermal-sensors = <&tboard_thermistor>; + + trips { + therm_est_trip: therm_est_trip { + temperature = <40000>; + type = "active"; + hysteresis = <1000>; + }; + }; + + cooling-maps { + map0 { + trip = <&therm_est_trip>; + cooling-device = <&dummy_cool_dev THERMAL_NO_LIMIT THERMAL_NO_LIMIT>; + contribution = <100>; + }; + + }; + }; +};