i.MX6 SoC has onchip temperature sensor. Add driver for this sensor.
Signed-off-by: Nitin Garg nitin.garg@freescale.com ---
Changes in v4: None Changes in v3: None Changes in v2: None
drivers/Makefile | 1 + drivers/thermal/Makefile | 8 +++ drivers/thermal/imx_thermal.c | 137 +++++++++++++++++++++++++++++++++++++++++ include/imx_thermal.h | 15 +++++ 4 files changed, 161 insertions(+) create mode 100644 drivers/thermal/Makefile create mode 100644 drivers/thermal/imx_thermal.c create mode 100644 include/imx_thermal.h
diff --git a/drivers/Makefile b/drivers/Makefile index b22b109..fc57e49 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -16,3 +16,4 @@ obj-y += watchdog/ obj-$(CONFIG_QE) += qe/ obj-y += memory/ obj-y += pwm/ +obj-y += thermal/ diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile new file mode 100644 index 0000000..04ae395 --- /dev/null +++ b/drivers/thermal/Makefile @@ -0,0 +1,8 @@ +# +# (C) Copyright 2014 Freescale Semiconductor, Inc. +# Author: Nitin Garg nitin.garg@freescale.com +# +# SPDX-License-Identifier: GPL-2.0+ +# + +obj-$(CONFIG_IMX6_THERMAL) += imx_thermal.o diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c new file mode 100644 index 0000000..3b53b61 --- /dev/null +++ b/drivers/thermal/imx_thermal.c @@ -0,0 +1,137 @@ +/* + * (C) Copyright 2014 Freescale Semiconductor, Inc. + * Author: Nitin Garg nitin.garg@freescale.com + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <config.h> +#include <common.h> +#include <div64.h> +#include <fuse.h> +#include <asm/io.h> +#include <asm/arch/crm_regs.h> +#include <asm/arch/clock.h> + +#define TEMPERATURE_MIN -40 +#define TEMPERATURE_HOT 80 +#define TEMPERATURE_MAX 125 +#define FACTOR0 10000000 +#define FACTOR1 15976 +#define FACTOR2 4297157 +#define MEASURE_FREQ 327 + +static int read_cpu_temperature(u32 fuse) +{ + int temperature; + unsigned int reg, n_meas; + struct anatop_regs *anatop = (struct anatop_regs *)ANATOP_BASE_ADDR; + int t1, n1; + u32 c1, c2; + u64 temp64; + + /* make sure pll3 is enabled for thermal sensor */ + enable_pll3(); + + /* + * Sensor data layout: + * [31:20] - sensor value @ 25C + * We use universal formula now and only need sensor value @ 25C + * slope = 0.4297157 - (0.0015976 * 25C fuse) + */ + n1 = fuse >> 20; + t1 = 25; /* t1 always 25C */ + + /* + * Derived from linear interpolation: + * slope = 0.4297157 - (0.0015976 * 25C fuse) + * slope = (FACTOR2 - FACTOR1 * n1) / FACTOR0 + * (Nmeas - n1) / (Tmeas - t1) = slope + * We want to reduce this down to the minimum computation necessary + * for each temperature read. Also, we want Tmeas in millicelsius + * and we don't want to lose precision from integer division. So... + * Tmeas = (Nmeas - n1) / slope + t1 + * milli_Tmeas = 1000 * (Nmeas - n1) / slope + 1000 * t1 + * milli_Tmeas = -1000 * (n1 - Nmeas) / slope + 1000 * t1 + * Let constant c1 = (-1000 / slope) + * milli_Tmeas = (n1 - Nmeas) * c1 + 1000 * t1 + * Let constant c2 = n1 *c1 + 1000 * t1 + * milli_Tmeas = c2 - Nmeas * c1 + */ + temp64 = FACTOR0; + temp64 *= 1000; + do_div(temp64, FACTOR1 * n1 - FACTOR2); + c1 = temp64; + c2 = n1 * c1 + 1000 * t1; + + /* + * now we only use single measure, every time we read + * the temperature, we will power on/down anadig thermal + * module + */ + writel(BM_ANADIG_TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_clr); + writel(BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_set); + + /* setup measure freq */ + reg = readl(&anatop->tempsense1); + reg &= ~BM_ANADIG_TEMPSENSE1_MEASURE_FREQ; + reg |= MEASURE_FREQ; + writel(reg, &anatop->tempsense1); + + /* start the measurement process */ + writel(BM_ANADIG_TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_clr); + writel(BM_ANADIG_TEMPSENSE0_FINISHED, &anatop->tempsense0_clr); + writel(BM_ANADIG_TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_set); + + /* make sure that the latest temp is valid */ + while ((readl(&anatop->tempsense0) & + BM_ANADIG_TEMPSENSE0_FINISHED) == 0) + udelay(10000); + + /* read temperature count */ + reg = readl(&anatop->tempsense0); + n_meas = (reg & BM_ANADIG_TEMPSENSE0_TEMP_VALUE) + >> BP_ANADIG_TEMPSENSE0_TEMP_VALUE; + writel(BM_ANADIG_TEMPSENSE0_FINISHED, &anatop->tempsense0_clr); + + /* milli_Tmeas = c2 - Nmeas * c1 */ + temperature = (c2 - n_meas * c1)/1000; + + /* power down anatop thermal sensor */ + writel(BM_ANADIG_TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_set); + writel(BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_clr); + + return temperature; +} + +void check_cpu_temperature(void) +{ + int cpu_tmp = 0; + u32 fuse = ~0; + + /* Read Temperature calibration data fuse */ + fuse_read(1, 6, &fuse); + + /* Check for valid fuse */ + if (fuse == 0 || fuse == ~0) { + printf("CPU: Temperature: invalid data, fuse: 0x%x\n", fuse); + return; + } + + cpu_tmp = read_cpu_temperature(fuse); + while (cpu_tmp > TEMPERATURE_MIN && cpu_tmp < TEMPERATURE_MAX) { + if (cpu_tmp >= TEMPERATURE_HOT) { + printf("CPU is %d C, too hot to boot, waiting...\n", + cpu_tmp); + udelay(5000000); + cpu_tmp = read_cpu_temperature(fuse); + } else { + break; + } + } + + if (cpu_tmp > TEMPERATURE_MIN && cpu_tmp < TEMPERATURE_MAX) + printf("CPU: Temperature %d C\n", cpu_tmp); + else + printf("CPU: Temperature: invalid sensor data\n"); +} diff --git a/include/imx_thermal.h b/include/imx_thermal.h new file mode 100644 index 0000000..979664a --- /dev/null +++ b/include/imx_thermal.h @@ -0,0 +1,15 @@ +/* + * IMX Thermal Defines + *------------------------------------------------------------------- + * + * Copyright 2014 Freescale Semiconductor, Inc + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef __IMX6_THERMAL_H__ +#define __IMX6_THERMAL_H__ + +void check_cpu_temperature(void); + +#endif /* __IMX6_THERMAL_H__ */