diff options
Diffstat (limited to 'drivers/thermal/imx_thermal.c')
| -rw-r--r-- | drivers/thermal/imx_thermal.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c new file mode 100644 index 0000000..0bd9cfd --- /dev/null +++ b/drivers/thermal/imx_thermal.c @@ -0,0 +1,175 @@ +/* + * (C) Copyright 2014 Freescale Semiconductor, Inc. + * Author: Nitin Garg <nitin.garg@freescale.com> + * Ye Li <Ye.Li@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/clock.h> +#include <dm.h> +#include <errno.h> +#include <malloc.h> +#include <thermal.h> +#include <imx_thermal.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 + +#define TEMPSENSE0_TEMP_CNT_SHIFT 8 +#define TEMPSENSE0_TEMP_CNT_MASK (0xfff << TEMPSENSE0_TEMP_CNT_SHIFT) +#define TEMPSENSE0_FINISHED (1 << 2) +#define TEMPSENSE0_MEASURE_TEMP (1 << 1) +#define TEMPSENSE0_POWER_DOWN (1 << 0) +#define MISC0_REFTOP_SELBIASOFF (1 << 3) +#define TEMPSENSE1_MEASURE_FREQ 0xffff + +static int read_cpu_temperature(struct udevice *dev) +{ + int temperature; + unsigned int reg, n_meas; + const struct imx_thermal_plat *pdata = dev_get_platdata(dev); + struct anatop_regs *anatop = (struct anatop_regs *)pdata->regs; + unsigned int *priv = dev_get_priv(dev); + u32 fuse = *priv; + int t1, n1; + u32 c1, c2; + u64 temp64; + + /* + * 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(TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_clr); + writel(MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_set); + + /* setup measure freq */ + reg = readl(&anatop->tempsense1); + reg &= ~TEMPSENSE1_MEASURE_FREQ; + reg |= MEASURE_FREQ; + writel(reg, &anatop->tempsense1); + + /* start the measurement process */ + writel(TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_clr); + writel(TEMPSENSE0_FINISHED, &anatop->tempsense0_clr); + writel(TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_set); + + /* make sure that the latest temp is valid */ + while ((readl(&anatop->tempsense0) & + TEMPSENSE0_FINISHED) == 0) + udelay(10000); + + /* read temperature count */ + reg = readl(&anatop->tempsense0); + n_meas = (reg & TEMPSENSE0_TEMP_CNT_MASK) + >> TEMPSENSE0_TEMP_CNT_SHIFT; + writel(TEMPSENSE0_FINISHED, &anatop->tempsense0_clr); + + /* milli_Tmeas = c2 - Nmeas * c1 */ + temperature = (c2 - n_meas * c1)/1000; + + /* power down anatop thermal sensor */ + writel(TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_set); + writel(MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_clr); + + return temperature; +} + +int imx_thermal_get_temp(struct udevice *dev, int *temp) +{ + int cpu_tmp = 0; + + cpu_tmp = read_cpu_temperature(dev); + while (cpu_tmp > TEMPERATURE_MIN && cpu_tmp < TEMPERATURE_MAX) { + if (cpu_tmp >= TEMPERATURE_HOT) { + printf("CPU Temperature is %d C, too hot to boot, waiting...\n", + cpu_tmp); + udelay(5000000); + cpu_tmp = read_cpu_temperature(dev); + } else { + break; + } + } + + *temp = cpu_tmp; + + return 0; +} + +static const struct dm_thermal_ops imx_thermal_ops = { + .get_temp = imx_thermal_get_temp, +}; + +static int imx_thermal_probe(struct udevice *dev) +{ + unsigned int fuse = ~0; + + const struct imx_thermal_plat *pdata = dev_get_platdata(dev); + unsigned int *priv = dev_get_priv(dev); + + /* Read Temperature calibration data fuse */ + fuse_read(pdata->fuse_bank, pdata->fuse_word, &fuse); + + /* Check for valid fuse */ + if (fuse == 0 || fuse == ~0) { + printf("CPU: Thermal invalid data, fuse: 0x%x\n", fuse); + return -EPERM; + } + + *priv = fuse; + + enable_thermal_clk(); + + return 0; +} + +U_BOOT_DRIVER(imx_thermal) = { + .name = "imx_thermal", + .id = UCLASS_THERMAL, + .ops = &imx_thermal_ops, + .probe = imx_thermal_probe, + .priv_auto_alloc_size = sizeof(unsigned int), + .flags = DM_FLAG_PRE_RELOC, +}; |