Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964903AbdLVI57 (ORCPT ); Fri, 22 Dec 2017 03:57:59 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:36012 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964894AbdLVI5t (ORCPT ); Fri, 22 Dec 2017 03:57:49 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Lezcano , Leo Yan , Eduardo Valentin , Kevin Wangtao Subject: [PATCH 4.9 100/104] thermal/drivers/hisi: Simplify the temperature/step computation Date: Fri, 22 Dec 2017 09:47:06 +0100 Message-Id: <20171222084617.306177907@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171222084609.262099650@linuxfoundation.org> References: <20171222084609.262099650@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3246 Lines: 106 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Lezcano commit 48880b979cdc9ef5a70af020f42b8ba1e51dbd34 upstream. The step and the base temperature are fixed values, we can simplify the computation by converting the base temperature to milli celsius and use a pre-computed step value. That saves us a lot of mult + div for nothing at runtime. Take also the opportunity to change the function names to be consistent with the rest of the code. Signed-off-by: Daniel Lezcano Reviewed-by: Leo Yan Tested-by: Leo Yan Signed-off-by: Eduardo Valentin Signed-off-by: Kevin Wangtao Signed-off-by: Greg Kroah-Hartman --- drivers/thermal/hisi_thermal.c | 41 ++++++++++++++++++++++++++++------------- 1 file changed, 28 insertions(+), 13 deletions(-) --- a/drivers/thermal/hisi_thermal.c +++ b/drivers/thermal/hisi_thermal.c @@ -35,8 +35,9 @@ #define TEMP0_RST_MSK (0x1C) #define TEMP0_VALUE (0x28) -#define HISI_TEMP_BASE (-60) +#define HISI_TEMP_BASE (-60000) #define HISI_TEMP_RESET (100000) +#define HISI_TEMP_STEP (784) #define HISI_MAX_SENSORS 4 @@ -61,19 +62,32 @@ struct hisi_thermal_data { void __iomem *regs; }; -/* in millicelsius */ -static inline int _step_to_temp(int step) +/* + * The temperature computation on the tsensor is as follow: + * Unit: millidegree Celsius + * Step: 255/200 (0.7843) + * Temperature base: -60°C + * + * The register is programmed in temperature steps, every step is 784 + * millidegree and begins at -60 000 m°C + * + * The temperature from the steps: + * + * Temp = TempBase + (steps x 784) + * + * and the steps from the temperature: + * + * steps = (Temp - TempBase) / 784 + * + */ +static inline int hisi_thermal_step_to_temp(int step) { - /* - * Every step equals (1 * 200) / 255 celsius, and finally - * need convert to millicelsius. - */ - return (HISI_TEMP_BASE * 1000 + (step * 200000 / 255)); + return HISI_TEMP_BASE + (step * HISI_TEMP_STEP); } -static inline long _temp_to_step(long temp) +static inline long hisi_thermal_temp_to_step(long temp) { - return ((temp - HISI_TEMP_BASE * 1000) * 255) / 200000; + return (temp - HISI_TEMP_BASE) / HISI_TEMP_STEP; } static long hisi_thermal_get_sensor_temp(struct hisi_thermal_data *data, @@ -99,7 +113,7 @@ static long hisi_thermal_get_sensor_temp usleep_range(3000, 5000); val = readl(data->regs + TEMP0_VALUE); - val = _step_to_temp(val); + val = hisi_thermal_step_to_temp(val); mutex_unlock(&data->thermal_lock); @@ -126,10 +140,11 @@ static void hisi_thermal_enable_bind_irq writel((sensor->id << 12), data->regs + TEMP0_CFG); /* enable for interrupt */ - writel(_temp_to_step(sensor->thres_temp) | 0x0FFFFFF00, + writel(hisi_thermal_temp_to_step(sensor->thres_temp) | 0x0FFFFFF00, data->regs + TEMP0_TH); - writel(_temp_to_step(HISI_TEMP_RESET), data->regs + TEMP0_RST_TH); + writel(hisi_thermal_temp_to_step(HISI_TEMP_RESET), + data->regs + TEMP0_RST_TH); /* enable module */ writel(0x1, data->regs + TEMP0_RST_MSK);