From 02c17c0f825c2d22de05c18e97982796b634eff3 Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Thu, 19 Oct 2017 19:05:46 +0200 Subject: [PATCH] thermal/drivers/hisi: Simplify the temperature/step computation 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(-) diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c index 26bb8e2..ea77aac9 100644 --- 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(struct hisi_thermal_data *data, 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_sensor 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); -- 2.7.4