From patchwork Sun Jan 18 23:55:49 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Caesar Wang X-Patchwork-Id: 5654401 X-Patchwork-Delegate: eduardo.valentin@ti.com Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 16AE8C058D for ; Sun, 18 Jan 2015 23:56:44 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3E4D2202FF for ; Sun, 18 Jan 2015 23:56:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CA6C20306 for ; Sun, 18 Jan 2015 23:56:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751702AbbARX42 (ORCPT ); Sun, 18 Jan 2015 18:56:28 -0500 Received: from regular1.263xmail.com ([211.150.99.139]:43653 "EHLO regular1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751678AbbARX40 (ORCPT ); Sun, 18 Jan 2015 18:56:26 -0500 Received: from caesar.wang?rock-chips.com (unknown [192.168.167.129]) by regular1.263xmail.com (Postfix) with SMTP id 9F11F3823; Mon, 19 Jan 2015 07:56:23 +0800 (CST) X-263anti-spam: KSV:0; X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-KSVirus-check: 0 X-ABS-CHECKED: 4 X-ADDR-CHECKED: 0 Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.263.net (Postfix) with ESMTP id 228F212832; Mon, 19 Jan 2015 07:56:14 +0800 (CST) X-RL-SENDER: caesar.wang@rock-chips.com X-SENDER-IP: 173.208.56.148 X-LOGIN-NAME: caesar.wang@rock-chips.com X-UNIQUE-TAG: X-ATTACHMENT-NUM: 0 X-SENDER: wxt@rock-chips.com X-DNS-TYPE: 5 Received: from unknown (173.208.56.148.rdns.ubiquityservers.com [173.208.56.148]) by smtp.263.net (Postfix) whith SMTP id 276475OOGV8; Mon, 19 Jan 2015 07:56:22 +0800 (CST) From: Caesar Wang To: Heiko Stuebner , Zhang Rui , Eduardo Valentin Cc: Dmitry Torokhov , Caesar Wang , linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] thermal: rockchip: make temperature reporting much more accurate Date: Mon, 19 Jan 2015 07:55:49 +0800 Message-Id: <1421625349-14101-2-git-send-email-wxt@rock-chips.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1421625349-14101-1-git-send-email-wxt@rock-chips.com> References: <1421625349-14101-1-git-send-email-wxt@rock-chips.com> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_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 In general, the kernel should report temperature readings exactly as reported by the hardware. The cpu / gpu thermal driver works in 5 degree increments,but we ought to do more accurate. The temperature will do linear interpolation between the entries in the table. Test= $md5sum /dev/zero & $while true; do grep "" /sys/class/thermal/thermal_zone[1-2]/temp; sleep .5; done e.g. We can get the result as follows: /sys/class/thermal/thermal_zone1/temp:39994 /sys/class/thermal/thermal_zone2/temp:39086 /sys/class/thermal/thermal_zone1/temp:39994 /sys/class/thermal/thermal_zone2/temp:39540 /sys/class/thermal/thermal_zone1/temp:39540 /sys/class/thermal/thermal_zone2/temp:39540 /sys/class/thermal/thermal_zone1/temp:39540 /sys/class/thermal/thermal_zone2/temp:39994 Signed-off-by: Caesar Wang Reviewed-by: Dmitry Torokhov --- Changes in v2: Reviewed-by: Dmitry Torokhov drivers/thermal/rockchip_thermal.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c index 1bcddfc..a7ae23a 100644 --- a/drivers/thermal/rockchip_thermal.c +++ b/drivers/thermal/rockchip_thermal.c @@ -193,19 +193,18 @@ static u32 rk_tsadcv2_temp_to_code(long temp) static long rk_tsadcv2_code_to_temp(u32 code) { - int high, low, mid; - - low = 0; - high = ARRAY_SIZE(v2_code_table) - 1; - mid = (high + low) / 2; + unsigned int low = 0; + unsigned int high = ARRAY_SIZE(v2_code_table) - 1; + unsigned int mid = (low + high) / 2; + unsigned int scale; if (code > v2_code_table[low].code || code < v2_code_table[high].code) return 125000; /* No code available, return max temperature */ while (low <= high) { - if (code >= v2_code_table[mid].code && code < - v2_code_table[mid - 1].code) - return v2_code_table[mid].temp; + if (code >= v2_code_table[mid].code && + code < v2_code_table[mid - 1].code) + break; else if (code < v2_code_table[mid].code) low = mid + 1; else @@ -213,7 +212,16 @@ static long rk_tsadcv2_code_to_temp(u32 code) mid = (low + high) / 2; } - return 125000; + /* + * The 5C granularity provided by the table is too much. Let's + * assume that the relationship between sensor readings and + * temperature between 2 table entries is linear and extrapolate + * to produce less granular result. + */ + scale = (v2_code_table[mid].temp - v2_code_table[mid - 1].temp) / + (v2_code_table[mid - 1].code - v2_code_table[mid].code); + return v2_code_table[mid - 1].temp + + (v2_code_table[mid - 1].code - code) * scale; } /**