Based on v3.5-rc4
This patch add basic thermal driver support for the imx6q platform. This was implemented by hooking into the linux thermal framework which provides sysfs temperature readings and other data and a method to shutdown the system if it gets too hot.
A major change in this revision is that cooling device implementation was removed as it is dependent on cpufreq and no imx6q cpufreq exist upstream and there is no recent activity on efforts to do so.
Other changes in v6. 1. Fixed several problems that were pointed out in v5 review. 2. Re-worked the sensor reading code to better handle suspend/resume case 3. Made various naming changes to make it more specific to the anatop peripheral instead of the imx6q platform. This should reduce the changes required to use this driver in future platforms. 4. Removed test support for imx6q parts without calibrated temperature sensor fuses. These devices will simply exit thermal driver initialization with a warning message. 5. Made the thermal driver and the anatopmfd driver defaulted to be enabled in the Kconfig files which will still dependend on imx6q_soc being enabled. Not sure if this is the right place to do this or if it should be done in the defconfig file.
Known future work will be to add back in cooling device support once cpufreq is supported. Improvements to coincide with that work may involve adding the active cooling trip points into device tree for hardware application specific settings.
link to previous submissions: v5" https://lkml.org/lkml/2012/6/20/57 v4: http://comments.gmane.org/gmane.linux.acpi.devel/51779 v3: http://www.spinics.net/lists/arm-kernel/msg155955.html v2: http://www.spinics.net/lists/arm-kernel/msg155790.html v1: http://www.spinics.net/lists/arm-kernel/msg155111.html
Changes in v5: 1. Modified to use anatop mfd driver for accessing anatop registers 2. Made necessary changes to work with latest generic CPU cooling code. 3. Added Config changes and functionality to allow testing on parts without without programmed temperature sensor calibration values. 4. General cleanup and addition of comments.
Changes in v4: 1. Removed bad suspend/resume assignment into thermal class. After further examination and discussion with SoC designers, a sequence is now used for making measurements that is is unaffected by system suspendresumes. Temp Sensor automatically powers off in hardware during the low power mode caused by a system suspend. 2. Moved some structures from static to dynamic allocation. 3. Added some noise handling to temperatuer sensor readings.
Changes in v3: 1. Fixed the various issues pointed out in v2 2. Made other code cleanup and a bit of re-organizing 3. Removed unecessary platform driver and device.
Changes in v2: 1. Cleaned up some style issues pointed out in v1 2. Made various other code cleanup and re-organizing 3. Added temperature sensor calibration 4. Created platform driver and device to hook into pm suspend.
Performed some basic testing to ensure proper cooling operating. If you want to test this, full testing requires imx6q cpufreq implementation (not yet in v3.5).
Robert Lee (1): ARM: imx: Add basic imx6q thermal driver
arch/arm/boot/dts/imx6q.dtsi | 5 + drivers/mfd/Kconfig | 1 + drivers/thermal/Kconfig | 9 + drivers/thermal/Makefile | 1 + drivers/thermal/imx_anatop_thermal.c | 465 ++++++++++++++++++++++++++++++++++ 5 files changed, 481 insertions(+) create mode 100644 drivers/thermal/imx_anatop_thermal.c
Add imx anatop peripheral thermal driver and use it for imx6q builds. This driver hooks into the linux thermal framework which provides a sysfs interface for temperature readings and other information and a mechanism to shutdown the system upon crossing a critical temperature trip point.
Only the sysfs interface and a critcial trip are supported by this patch and not any active trip points or cooling devices.
The thermal driver is defaulted to be enabled which required the anatopmfd driver to be defaulted to enabled.
Signed-off-by: Robert Lee rob.lee@linaro.org --- arch/arm/boot/dts/imx6q.dtsi | 5 + drivers/mfd/Kconfig | 1 + drivers/thermal/Kconfig | 9 + drivers/thermal/Makefile | 1 + drivers/thermal/imx_anatop_thermal.c | 465 ++++++++++++++++++++++++++++++++++ 5 files changed, 481 insertions(+) create mode 100644 drivers/thermal/imx_anatop_thermal.c
diff --git a/arch/arm/boot/dts/imx6q.dtsi b/arch/arm/boot/dts/imx6q.dtsi index d026f30..b53a16a 100644 --- a/arch/arm/boot/dts/imx6q.dtsi +++ b/arch/arm/boot/dts/imx6q.dtsi @@ -449,6 +449,10 @@ anatop-min-voltage = <725000>; anatop-max-voltage = <1450000>; }; + + thermal { + compatible ="fsl,anatop-thermal"; + }; };
usbphy@020c9000 { /* USBPHY1 */ @@ -666,6 +670,7 @@ };
ocotp@021bc000 { + compatible = "fsl,imx6q-ocotp"; reg = <0x021bc000 0x4000>; };
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig index e129c82..552fae3 100644 --- a/drivers/mfd/Kconfig +++ b/drivers/mfd/Kconfig @@ -915,6 +915,7 @@ config MFD_STA2X11 config MFD_ANATOP bool "Support for Freescale i.MX on-chip ANATOP controller" depends on SOC_IMX6Q + default y help Select this option to enable Freescale i.MX on-chip ANATOP MFD controller. This controller embeds regulator and diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index 04c6796..a35a35e 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -30,6 +30,15 @@ config CPU_THERMAL and not the ACPI interface. If you want this support, you should say Y or M here.
+config IMX_ANATOP_THERMAL + bool "imx anatop soc thermal driver" + depends on MFD_ANATOP && CPU_THERMAL + default y + help + Enable the on-chip temperature sensor and register the linux thermal + framework to provide SoC temperature data to sysfs and a basic + shutdown mechanism to prevent the SoC from overheating. + config SPEAR_THERMAL bool "SPEAr thermal sensor driver" depends on THERMAL diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile index 4636e35..4dd4570 100644 --- a/drivers/thermal/Makefile +++ b/drivers/thermal/Makefile @@ -6,3 +6,4 @@ obj-$(CONFIG_THERMAL) += thermal_sys.o obj-$(CONFIG_CPU_THERMAL) += cpu_cooling.o obj-$(CONFIG_SPEAR_THERMAL) += spear_thermal.o obj-$(CONFIG_EXYNOS_THERMAL) += exynos_thermal.o +obj-$(CONFIG_IMX_ANATOP_THERMAL) += imx_anatop_thermal.o diff --git a/drivers/thermal/imx_anatop_thermal.c b/drivers/thermal/imx_anatop_thermal.c new file mode 100644 index 0000000..a932fe8 --- /dev/null +++ b/drivers/thermal/imx_anatop_thermal.c @@ -0,0 +1,465 @@ +/* + * Copyright 2012 Freescale Semiconductor, Inc. + * Copyright 2012 Linaro Ltd. + * + * The code contained herein is licensed under the GNU General Public + * License. You may obtain a copy of the GNU General Public License + * Version 2 or later at the following locations: + * + * http://www.opensource.org/licenses/gpl-license.html + * http://www.gnu.org/copyleft/gpl.html + */ + +/* + * Thermal driver for i.MX anatop systems. Implented by hooking in to the + * linux thermal framework. + */ + +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/dmi.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/mfd/anatop.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> +#include <linux/smp.h> +#include <linux/slab.h> +#include <linux/syscalls.h> +#include <linux/thermal.h> +#include <linux/types.h> + +/* register define of anatop */ +#define HW_ANADIG_ANA_MISC0 0x00000150 +#define HW_ANADIG_ANA_MISC0_SET 0x00000154 +#define HW_ANADIG_ANA_MISC0_CLR 0x00000158 +#define HW_ANADIG_ANA_MISC0_TOG 0x0000015c +#define BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF 0x00000008 + +#define HW_ANADIG_TEMPSENSE0 0x00000180 +#define HW_ANADIG_TEMPSENSE0_SET 0x00000184 +#define HW_ANADIG_TEMPSENSE0_CLR 0x00000188 +#define HW_ANADIG_TEMPSENSE0_TOG 0x0000018c + +#define BP_ANADIG_TEMPSENSE0_TEMP_VALUE 8 +#define BM_ANADIG_TEMPSENSE0_TEMP_VALUE 0x000FFF00 +#define BM_ANADIG_TEMPSENSE0_FINISHED 0x00000004 +#define BM_ANADIG_TEMPSENSE0_MEASURE_TEMP 0x00000002 +#define BM_ANADIG_TEMPSENSE0_POWER_DOWN 0x00000001 + +#define HW_ANADIG_TEMPSENSE1 0x00000190 +#define HW_ANADIG_TEMPSENSE1_SET 0x00000194 +#define HW_ANADIG_TEMPSENSE1_CLR 0x00000198 +#define BP_ANADIG_TEMPSENSE1_MEASURE_FREQ 0 +#define BM_ANADIG_TEMPSENSE1_MEASURE_FREQ 0x0000FFFF + +#define HW_OCOTP_ANA1 0x000004E0 + +#define IMX_THERMAL_POLLING_FREQUENCY_MS 1000 + +#define IMX_ANATOP_TS_NOISE_MARGIN 3000 /* in millicelsius */ +#define IMX_ANATOP_TS_NOISE_COUNT 3 + +/* anatop temperature sensor data */ +struct imx_anatop_tsdata { + int c1, c2; + u32 noise_margin; /* in millicelsius */ + int last_temp; /* in millicelsius */ + /* + * When filtering noise, if consecutive measurements are each higher + * up to consec_high_limit times, assume changing temperature readings + * to be valid and not noise. + */ + u32 consec_high_limit; + bool handle_suspend; + struct anatop *anatopmfd; + +}; + +struct imx_anatop_thdata { + struct thermal_zone_device *tzdev; + struct imx_anatop_tsdata sensor_data; + struct thermal_zone_device_ops dev_ops; + unsigned int crit_temp_level; + void __iomem *ocotp_base; +}; + +static inline int anatop_get_temp(int *temp, struct thermal_zone_device *tzdev) +{ + unsigned int n_meas; + unsigned int reg; + struct imx_anatop_tsdata *sd; + + sd = &((struct imx_anatop_thdata *)tzdev->devdata)->sensor_data; + + + do { + /* + * Every time we measure the temperature, we will power on the + * temperature sensor, enable measurements, take a reading, + * disable measurements, power off the temperature sensor. + */ + sd->handle_suspend = false; + + anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0, + BM_ANADIG_TEMPSENSE0_POWER_DOWN); + anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, + BM_ANADIG_TEMPSENSE0_MEASURE_TEMP, + BM_ANADIG_TEMPSENSE0_MEASURE_TEMP); + /* + * According to the anatop temp sensor designers, it may require + * up to ~17us to complete a measurement (imx6q). + * But this timing isn't checked on every part nor is it + * specified in the datasheet, so sleeping at least 1ms should + * provide plenty of time. Sleeping longer than 1ms is ok so no + * need for usleep_range */ + msleep(1); + + reg = anatop_read_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0); + + anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0, + BM_ANADIG_TEMPSENSE0_MEASURE_TEMP); + anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, + BM_ANADIG_TEMPSENSE0_POWER_DOWN, + BM_ANADIG_TEMPSENSE0_POWER_DOWN); + + /* if we had a suspend and resume event, we will re-take the reading */ + } while (sd->handle_suspend); + + if (!(reg & BM_ANADIG_TEMPSENSE0_FINISHED) && + (reg & BM_ANADIG_TEMPSENSE0_TEMP_VALUE)) { + dev_dbg(&tzdev->device, + "Temp sensor error: reading never finished"); + return -EAGAIN; + } + + n_meas = (reg & BM_ANADIG_TEMPSENSE0_TEMP_VALUE) + >> BP_ANADIG_TEMPSENSE0_TEMP_VALUE; + + /* See anatop_process_ts_fuse_data() for forumla derivation. */ + *temp = sd->c2 + (sd->c1 * n_meas); + + dev_dbg(&tzdev->device, "Temperature: %d\n", *temp / 1000); + return 0; +} + +static int th_sys_get_temp(struct thermal_zone_device *tzdev, + unsigned long *temp) +{ + int i, total = 0, tmp = 0; + const u8 loop = 5; + u32 consec_high = 0; + + struct imx_anatop_tsdata *sd; + + sd = &((struct imx_anatop_thdata *)tzdev->devdata)->sensor_data; + + /* + * Measure temperature and handle noise + * + * While the anatop temperature sensor is designed to minimize being + * affected by system noise, it's safest to run sanity checks and + * perform any necessary filtering, if a noise_margin has been defined. + */ + for (i = 0; (sd->noise_margin) && (i < loop); i++) { + /* + * We expect the sensor reading to be successful, but if for + * unknow reason it is not, use the data from the last + * successful reading + */ + if (anatop_get_temp(&tmp, tzdev)) { + tmp = sd->last_temp; + continue; + } + + if ((abs(tmp - sd->last_temp) <= sd->noise_margin) || + (consec_high >= sd->consec_high_limit)) { + sd->last_temp = tmp; + i = 0; + break; + } + if (tmp > sd->last_temp) + consec_high++; + + /* + * ignore first measurement as the previous measurement was + * a long time ago. + */ + if (i) + total += tmp; + + sd->last_temp = tmp; + } + + if (sd->noise_margin && i) + tmp = total / (loop - 1); + + /* + * The thermal framework code stores temperature in unsigned long. Also, + * it has references to "millicelsius" which limits the lowest + * temperature possible (compared to Kelvin). + */ + if (tmp > 0) + *temp = tmp; + else + *temp = 0; + return 0; +} + +static int th_sys_get_mode(struct thermal_zone_device *tzdev, + enum thermal_device_mode *mode) +{ + *mode = THERMAL_DEVICE_ENABLED; + return 0; +} + +static int th_sys_get_trip_type(struct thermal_zone_device *tzdev, int trip, + enum thermal_trip_type *type) +{ + *type = THERMAL_TRIP_CRITICAL; + return 0; +} + +static int th_sys_get_crit_temp(struct thermal_zone_device *tzdev, + unsigned long *temp) +{ + struct imx_anatop_thdata *p; + + p = (struct imx_anatop_thdata *)tzdev->devdata; + *temp = p->crit_temp_level; + return 0; +} + +static int th_sys_get_trip_temp(struct thermal_zone_device *tzdev, int trip, + unsigned long *temp) +{ + /* only a critical trip point is supported, for now. */ + return th_sys_get_crit_temp(tzdev, temp); +} + +static int __devinit anatop_process_ts_fuse_data(unsigned int fuse_data, + struct imx_anatop_thdata *thermal_data) +{ + int t1, t2, n1, n2; + struct imx_anatop_tsdata *sd = &thermal_data->sensor_data; + struct thermal_zone_device *tzdev = thermal_data->tzdev; + + + if (fuse_data == 0 || fuse_data == 0xffffffff) { + dev_warn(&tzdev->device, "WARNING: Disabling CPU thermal " + "protection (invalid calibration value of %x detected\n" + , fuse_data); + return -EINVAL; + } + + /* + * Fuse data layout: + * [31:20] sensor value @ 25C + * [19:8] sensor value of hot + * [7:0] hot temperature value + */ + n1 = fuse_data >> 20; + n2 = (fuse_data & 0xfff00) >> 8; + t2 = fuse_data & 0xff; + t1 = 25; /* t1 always 25C */ + + dev_dbg(&tzdev->device, " -- temperature sensor calibration data --\n"); + dev_dbg(&tzdev->device, "HW_OCOTP_ANA1: %x\n", fuse_data); + dev_dbg(&tzdev->device, "n1: %d\nn2: %d\nt1: %d\nt2: %d\n", n1, n2, t1, + t2); + + /* + * Derived from linear interpolation, + * Tmeas = T2 + (Nmeas - N2) * (T1 - T2) / (N1 - N2) + * 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... + * milli_Tmeas = 1000 * T2 + 1000 * (Nmeas - N2) * (T1 - T2) / (N1 - N2) + * Let constant c1 = 1000 * (T1 - T2) / (N1 - N2) + * milli_Tmeas = (1000 * T2) + c1 * (Nmeas - N2) + * milli_Tmeas = (1000 * T2) + (c1 * Nmeas) - (c1 * N2) + * Let constant c2 = (1000 * T2) - (c1 * N2) + * milli_Tmeas = c2 + (c1 * Nmeas) + */ + sd->c1 = (1000 * (t1 - t2)) / (n1 - n2); + sd->c2 = (1000 * t2) - (sd->c1 * n2); + + dev_dbg(&tzdev->device, "c1: %i\n", sd->c1); + dev_dbg(&tzdev->device, "c2: %i\n", sd->c2); + return 0; +} + +static int anatop_thermal_suspend(struct platform_device *pdev, + pm_message_t state) +{ + struct imx_anatop_thdata *dd = platform_get_drvdata(pdev); + struct imx_anatop_tsdata *sd = &dd->sensor_data; + + /* power off the sensor during suspend */ + anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0, + BM_ANADIG_TEMPSENSE0_MEASURE_TEMP); + + anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, + BM_ANADIG_TEMPSENSE0_POWER_DOWN, + BM_ANADIG_TEMPSENSE0_POWER_DOWN); + return 0; +} + +static int anatop_thermal_resume(struct platform_device *pdev) +{ + struct imx_anatop_thdata *dd = platform_get_drvdata(pdev); + struct imx_anatop_tsdata *sd = &dd->sensor_data; + + sd->handle_suspend = true; + return 0; +} + +static int __devexit anatop_thermal_remove(struct platform_device *pdev) +{ + struct imx_anatop_thdata *dd = platform_get_drvdata(pdev); + + if (dd && dd->tzdev) + thermal_zone_device_unregister(dd->tzdev); + + if (dd->ocotp_base) + iounmap(dd->ocotp_base); + + dev_info(&pdev->dev, "imx thermal management unregistered\n"); + return 0; +} + +static int __devinit anatop_thermal_probe(struct platform_device *pdev) +{ + unsigned int fuse_data; + void __iomem *ocotp_base; + struct device_node *np_ocotp, *np_thermal; + static struct imx_anatop_thdata *therm_data; + struct anatop *anatopmfd = dev_get_drvdata(pdev->dev.parent); + + struct imx_anatop_tsdata *sd; + int ret; + + np_ocotp = of_find_compatible_node(NULL, NULL, "fsl,imx6q-ocotp"); + np_thermal = pdev->dev.of_node; + + if (!(np_ocotp && np_thermal && anatopmfd)) + return 0; + + ocotp_base = of_iomap(np_ocotp, 0); + + if (!ocotp_base) { + dev_err(&pdev->dev, "Could not retrieve ocotp-base\n"); + ret = -ENXIO; + goto err_unregister; + } + + fuse_data = readl_relaxed(ocotp_base + HW_OCOTP_ANA1); + + therm_data = devm_kzalloc(&pdev->dev, sizeof(struct imx_anatop_thdata), + GFP_KERNEL); + + + if (!therm_data) { + ret = -ENOMEM; + goto err_unregister; + } + + therm_data->dev_ops.get_temp = th_sys_get_temp; + therm_data->dev_ops.get_mode = th_sys_get_mode; + therm_data->dev_ops.get_trip_type = th_sys_get_trip_type; + therm_data->dev_ops.get_trip_temp = th_sys_get_trip_temp; + therm_data->dev_ops.get_crit_temp = th_sys_get_crit_temp; + + /* + * max die temp on imx parts using anatop is 105C, let's give some + * cushion for noise and possible temperature rise between measurements. + */ + therm_data->crit_temp_level = 100000; /* in millicelsius */ + + sd = &therm_data->sensor_data; + sd->noise_margin = IMX_ANATOP_TS_NOISE_MARGIN; + sd->consec_high_limit = IMX_ANATOP_TS_NOISE_COUNT; + sd->anatopmfd = anatopmfd; + + platform_set_drvdata(pdev, therm_data); + + ret = anatop_process_ts_fuse_data(fuse_data, therm_data); + + if (ret) { + dev_err(&pdev->dev, "Invalid temperature calibration data.\n"); + goto err_unregister; + } + + /* Make sure sensor is in known good state for measurements */ + anatop_write_reg(anatopmfd, HW_ANADIG_TEMPSENSE0, 0, + BM_ANADIG_TEMPSENSE0_POWER_DOWN); + + anatop_write_reg(anatopmfd, HW_ANADIG_TEMPSENSE0, 0, + BM_ANADIG_TEMPSENSE0_MEASURE_TEMP); + + anatop_write_reg(anatopmfd, HW_ANADIG_TEMPSENSE1, 0, + BM_ANADIG_TEMPSENSE1_MEASURE_FREQ); + + anatop_write_reg(anatopmfd, HW_ANADIG_ANA_MISC0_SET, + BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF, + BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF); + + anatop_write_reg(anatopmfd, HW_ANADIG_TEMPSENSE0, + BM_ANADIG_TEMPSENSE0_POWER_DOWN, + BM_ANADIG_TEMPSENSE0_POWER_DOWN); + + therm_data->tzdev = thermal_zone_device_register( + "Processor", 1, therm_data, &therm_data->dev_ops, 0, 0, 0, + IMX_THERMAL_POLLING_FREQUENCY_MS); + + if (IS_ERR(therm_data->tzdev)) { + dev_err(&pdev->dev, + "Failed to register thermal zone device\n"); + ret = -EINVAL; + goto err_unregister; + } + + dev_info(&pdev->dev, "imx thermal management registered\n"); + return 0; + +err_unregister: + anatop_thermal_remove(pdev); + return ret; +} + +static struct of_device_id __devinitdata of_anatop_thermal_match_tbl[] = { + { .compatible = "fsl,anatop-thermal", }, + { /* end */ } +}; + +static struct platform_driver anatop_thermal = { + .driver = { + .name = "anatop_thermal", + .owner = THIS_MODULE, + .of_match_table = of_anatop_thermal_match_tbl, + }, + .probe = anatop_thermal_probe, + .remove = anatop_thermal_remove, + .suspend = anatop_thermal_suspend, + .resume = anatop_thermal_resume, +}; + +static int __devinit anatop_thermal_init(void) +{ + return platform_driver_register(&anatop_thermal); +} +device_initcall(anatop_thermal_init); + +static void __exit anatop_thermal_exit(void) +{ + platform_driver_unregister(&anatop_thermal); +} +module_exit(anatop_thermal_exit); + +MODULE_AUTHOR("Freescale Semiconductor"); +MODULE_DESCRIPTION("i.MX anatop thermal driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:imx-anatop-thermal");
On Tue, Jun 26, 2012 at 11:51 PM, Robert Lee rob.lee@linaro.org wrote:
Add imx anatop peripheral thermal driver and use it for imx6q builds. This driver hooks into the linux thermal framework which provides a sysfs interface for temperature readings and other information and a mechanism to shutdown the system upon crossing a critical temperature trip point.
Only the sysfs interface and a critcial trip are supported by this patch and not any active trip points or cooling devices.
The thermal driver is defaulted to be enabled which required the anatopmfd driver to be defaulted to enabled.
Signed-off-by: Robert Lee rob.lee@linaro.org
arch/arm/boot/dts/imx6q.dtsi | 5 + drivers/mfd/Kconfig | 1 + drivers/thermal/Kconfig | 9 + drivers/thermal/Makefile | 1 + drivers/thermal/imx_anatop_thermal.c | 465 ++++++++++++++++++++++++++++++++++ 5 files changed, 481 insertions(+) create mode 100644 drivers/thermal/imx_anatop_thermal.c
diff --git a/arch/arm/boot/dts/imx6q.dtsi b/arch/arm/boot/dts/imx6q.dtsi index d026f30..b53a16a 100644 --- a/arch/arm/boot/dts/imx6q.dtsi +++ b/arch/arm/boot/dts/imx6q.dtsi @@ -449,6 +449,10 @@ anatop-min-voltage = <725000>; anatop-max-voltage = <1450000>; };
thermal {compatible ="fsl,anatop-thermal";}; }; usbphy@020c9000 { /* USBPHY1 */@@ -666,6 +670,7 @@ };
ocotp@021bc000 {
compatible = "fsl,imx6q-ocotp"; reg = <0x021bc000 0x4000>; };diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig index e129c82..552fae3 100644 --- a/drivers/mfd/Kconfig +++ b/drivers/mfd/Kconfig @@ -915,6 +915,7 @@ config MFD_STA2X11 config MFD_ANATOP bool "Support for Freescale i.MX on-chip ANATOP controller" depends on SOC_IMX6Q
default y help Select this option to enable Freescale i.MX on-chip ANATOP MFD controller. This controller embeds regulator anddiff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index 04c6796..a35a35e 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -30,6 +30,15 @@ config CPU_THERMAL and not the ACPI interface. If you want this support, you should say Y or M here.
+config IMX_ANATOP_THERMAL
bool "imx anatop soc thermal driver"depends on MFD_ANATOP && CPU_THERMAL
I forgot to replace "CPU_THERMAL" with "THERMAL"
default yhelpEnable the on-chip temperature sensor and register the linux thermalframework to provide SoC temperature data to sysfs and a basicshutdown mechanism to prevent the SoC from overheating.config SPEAR_THERMAL bool "SPEAr thermal sensor driver" depends on THERMAL diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile index 4636e35..4dd4570 100644 --- a/drivers/thermal/Makefile +++ b/drivers/thermal/Makefile @@ -6,3 +6,4 @@ obj-$(CONFIG_THERMAL) += thermal_sys.o obj-$(CONFIG_CPU_THERMAL) += cpu_cooling.o obj-$(CONFIG_SPEAR_THERMAL) += spear_thermal.o obj-$(CONFIG_EXYNOS_THERMAL) += exynos_thermal.o +obj-$(CONFIG_IMX_ANATOP_THERMAL) += imx_anatop_thermal.o diff --git a/drivers/thermal/imx_anatop_thermal.c b/drivers/thermal/imx_anatop_thermal.c new file mode 100644 index 0000000..a932fe8 --- /dev/null +++ b/drivers/thermal/imx_anatop_thermal.c @@ -0,0 +1,465 @@ +/*
- Copyright 2012 Freescale Semiconductor, Inc.
- Copyright 2012 Linaro Ltd.
- The code contained herein is licensed under the GNU General Public
- License. You may obtain a copy of the GNU General Public License
- Version 2 or later at the following locations:
- */
+/*
- Thermal driver for i.MX anatop systems. Implented by hooking in to the
- linux thermal framework.
- */
+#include <linux/delay.h> +#include <linux/device.h> +#include <linux/dmi.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/mfd/anatop.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> +#include <linux/smp.h> +#include <linux/slab.h> +#include <linux/syscalls.h> +#include <linux/thermal.h> +#include <linux/types.h>
+/* register define of anatop */ +#define HW_ANADIG_ANA_MISC0 0x00000150 +#define HW_ANADIG_ANA_MISC0_SET 0x00000154 +#define HW_ANADIG_ANA_MISC0_CLR 0x00000158 +#define HW_ANADIG_ANA_MISC0_TOG 0x0000015c +#define BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF 0x00000008
+#define HW_ANADIG_TEMPSENSE0 0x00000180 +#define HW_ANADIG_TEMPSENSE0_SET 0x00000184 +#define HW_ANADIG_TEMPSENSE0_CLR 0x00000188 +#define HW_ANADIG_TEMPSENSE0_TOG 0x0000018c
+#define BP_ANADIG_TEMPSENSE0_TEMP_VALUE 8 +#define BM_ANADIG_TEMPSENSE0_TEMP_VALUE 0x000FFF00 +#define BM_ANADIG_TEMPSENSE0_FINISHED 0x00000004 +#define BM_ANADIG_TEMPSENSE0_MEASURE_TEMP 0x00000002 +#define BM_ANADIG_TEMPSENSE0_POWER_DOWN 0x00000001
+#define HW_ANADIG_TEMPSENSE1 0x00000190 +#define HW_ANADIG_TEMPSENSE1_SET 0x00000194 +#define HW_ANADIG_TEMPSENSE1_CLR 0x00000198 +#define BP_ANADIG_TEMPSENSE1_MEASURE_FREQ 0 +#define BM_ANADIG_TEMPSENSE1_MEASURE_FREQ 0x0000FFFF
+#define HW_OCOTP_ANA1 0x000004E0
+#define IMX_THERMAL_POLLING_FREQUENCY_MS 1000
+#define IMX_ANATOP_TS_NOISE_MARGIN 3000 /* in millicelsius */ +#define IMX_ANATOP_TS_NOISE_COUNT 3
+/* anatop temperature sensor data */ +struct imx_anatop_tsdata {
int c1, c2;u32 noise_margin; /* in millicelsius */int last_temp; /* in millicelsius *//** When filtering noise, if consecutive measurements are each higher* up to consec_high_limit times, assume changing temperature readings* to be valid and not noise.*/u32 consec_high_limit;bool handle_suspend;struct anatop *anatopmfd;+};
+struct imx_anatop_thdata {
struct thermal_zone_device *tzdev;struct imx_anatop_tsdata sensor_data;struct thermal_zone_device_ops dev_ops;unsigned int crit_temp_level;void __iomem *ocotp_base;+};
+static inline int anatop_get_temp(int *temp, struct thermal_zone_device *tzdev) +{
unsigned int n_meas;unsigned int reg;struct imx_anatop_tsdata *sd;sd = &((struct imx_anatop_thdata *)tzdev->devdata)->sensor_data;do {/** Every time we measure the temperature, we will power on the* temperature sensor, enable measurements, take a reading,* disable measurements, power off the temperature sensor.*/sd->handle_suspend = false;anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0,BM_ANADIG_TEMPSENSE0_POWER_DOWN);anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP);/** According to the anatop temp sensor designers, it may require* up to ~17us to complete a measurement (imx6q).* But this timing isn't checked on every part nor is it* specified in the datasheet, so sleeping at least 1ms should* provide plenty of time. Sleeping longer than 1ms is ok so no* need for usleep_range */msleep(1);reg = anatop_read_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0);anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP);anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0,BM_ANADIG_TEMPSENSE0_POWER_DOWN,BM_ANADIG_TEMPSENSE0_POWER_DOWN);/* if we had a suspend and resume event, we will re-take the reading */} while (sd->handle_suspend);if (!(reg & BM_ANADIG_TEMPSENSE0_FINISHED) &&(reg & BM_ANADIG_TEMPSENSE0_TEMP_VALUE)) {dev_dbg(&tzdev->device,"Temp sensor error: reading never finished");return -EAGAIN;}n_meas = (reg & BM_ANADIG_TEMPSENSE0_TEMP_VALUE)>> BP_ANADIG_TEMPSENSE0_TEMP_VALUE;/* See anatop_process_ts_fuse_data() for forumla derivation. */*temp = sd->c2 + (sd->c1 * n_meas);dev_dbg(&tzdev->device, "Temperature: %d\n", *temp / 1000);return 0;+}
+static int th_sys_get_temp(struct thermal_zone_device *tzdev,
unsigned long *temp)+{
int i, total = 0, tmp = 0;const u8 loop = 5;u32 consec_high = 0;struct imx_anatop_tsdata *sd;sd = &((struct imx_anatop_thdata *)tzdev->devdata)->sensor_data;/** Measure temperature and handle noise** While the anatop temperature sensor is designed to minimize being* affected by system noise, it's safest to run sanity checks and* perform any necessary filtering, if a noise_margin has been defined.*/for (i = 0; (sd->noise_margin) && (i < loop); i++) {/** We expect the sensor reading to be successful, but if for* unknow reason it is not, use the data from the last* successful reading*/if (anatop_get_temp(&tmp, tzdev)) {tmp = sd->last_temp;continue;}if ((abs(tmp - sd->last_temp) <= sd->noise_margin) ||(consec_high >= sd->consec_high_limit)) {sd->last_temp = tmp;i = 0;break;}if (tmp > sd->last_temp)consec_high++;/** ignore first measurement as the previous measurement was* a long time ago.*/if (i)total += tmp;sd->last_temp = tmp;}if (sd->noise_margin && i)tmp = total / (loop - 1);/** The thermal framework code stores temperature in unsigned long. Also,* it has references to "millicelsius" which limits the lowest* temperature possible (compared to Kelvin).*/if (tmp > 0)*temp = tmp;else*temp = 0;return 0;+}
+static int th_sys_get_mode(struct thermal_zone_device *tzdev,
enum thermal_device_mode *mode)+{
*mode = THERMAL_DEVICE_ENABLED;return 0;+}
+static int th_sys_get_trip_type(struct thermal_zone_device *tzdev, int trip,
enum thermal_trip_type *type)+{
*type = THERMAL_TRIP_CRITICAL;return 0;+}
+static int th_sys_get_crit_temp(struct thermal_zone_device *tzdev,
unsigned long *temp)+{
struct imx_anatop_thdata *p;p = (struct imx_anatop_thdata *)tzdev->devdata;*temp = p->crit_temp_level;return 0;+}
+static int th_sys_get_trip_temp(struct thermal_zone_device *tzdev, int trip,
unsigned long *temp)+{
/* only a critical trip point is supported, for now. */return th_sys_get_crit_temp(tzdev, temp);+}
+static int __devinit anatop_process_ts_fuse_data(unsigned int fuse_data,
struct imx_anatop_thdata *thermal_data)+{
int t1, t2, n1, n2;struct imx_anatop_tsdata *sd = &thermal_data->sensor_data;struct thermal_zone_device *tzdev = thermal_data->tzdev;if (fuse_data == 0 || fuse_data == 0xffffffff) {dev_warn(&tzdev->device, "WARNING: Disabling CPU thermal ""protection (invalid calibration value of %x detected\n", fuse_data);return -EINVAL;}/** Fuse data layout:* [31:20] sensor value @ 25C* [19:8] sensor value of hot* [7:0] hot temperature value*/n1 = fuse_data >> 20;n2 = (fuse_data & 0xfff00) >> 8;t2 = fuse_data & 0xff;t1 = 25; /* t1 always 25C */dev_dbg(&tzdev->device, " -- temperature sensor calibration data --\n");dev_dbg(&tzdev->device, "HW_OCOTP_ANA1: %x\n", fuse_data);dev_dbg(&tzdev->device, "n1: %d\nn2: %d\nt1: %d\nt2: %d\n", n1, n2, t1,t2);/** Derived from linear interpolation,* Tmeas = T2 + (Nmeas - N2) * (T1 - T2) / (N1 - N2)* 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...* milli_Tmeas = 1000 * T2 + 1000 * (Nmeas - N2) * (T1 - T2) / (N1 - N2)* Let constant c1 = 1000 * (T1 - T2) / (N1 - N2)* milli_Tmeas = (1000 * T2) + c1 * (Nmeas - N2)* milli_Tmeas = (1000 * T2) + (c1 * Nmeas) - (c1 * N2)* Let constant c2 = (1000 * T2) - (c1 * N2)* milli_Tmeas = c2 + (c1 * Nmeas)*/sd->c1 = (1000 * (t1 - t2)) / (n1 - n2);sd->c2 = (1000 * t2) - (sd->c1 * n2);dev_dbg(&tzdev->device, "c1: %i\n", sd->c1);dev_dbg(&tzdev->device, "c2: %i\n", sd->c2);return 0;+}
+static int anatop_thermal_suspend(struct platform_device *pdev,
pm_message_t state)+{
struct imx_anatop_thdata *dd = platform_get_drvdata(pdev);struct imx_anatop_tsdata *sd = &dd->sensor_data;/* power off the sensor during suspend */anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP);anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0,BM_ANADIG_TEMPSENSE0_POWER_DOWN,BM_ANADIG_TEMPSENSE0_POWER_DOWN);return 0;+}
+static int anatop_thermal_resume(struct platform_device *pdev) +{
struct imx_anatop_thdata *dd = platform_get_drvdata(pdev);struct imx_anatop_tsdata *sd = &dd->sensor_data;sd->handle_suspend = true;return 0;+}
+static int __devexit anatop_thermal_remove(struct platform_device *pdev) +{
struct imx_anatop_thdata *dd = platform_get_drvdata(pdev);if (dd && dd->tzdev)thermal_zone_device_unregister(dd->tzdev);if (dd->ocotp_base)iounmap(dd->ocotp_base);dev_info(&pdev->dev, "imx thermal management unregistered\n");return 0;+}
+static int __devinit anatop_thermal_probe(struct platform_device *pdev) +{
unsigned int fuse_data;void __iomem *ocotp_base;struct device_node *np_ocotp, *np_thermal;static struct imx_anatop_thdata *therm_data;struct anatop *anatopmfd = dev_get_drvdata(pdev->dev.parent);struct imx_anatop_tsdata *sd;int ret;np_ocotp = of_find_compatible_node(NULL, NULL, "fsl,imx6q-ocotp");np_thermal = pdev->dev.of_node;if (!(np_ocotp && np_thermal && anatopmfd))return 0;ocotp_base = of_iomap(np_ocotp, 0);if (!ocotp_base) {dev_err(&pdev->dev, "Could not retrieve ocotp-base\n");ret = -ENXIO;goto err_unregister;}fuse_data = readl_relaxed(ocotp_base + HW_OCOTP_ANA1);therm_data = devm_kzalloc(&pdev->dev, sizeof(struct imx_anatop_thdata),GFP_KERNEL);if (!therm_data) {ret = -ENOMEM;goto err_unregister;}therm_data->dev_ops.get_temp = th_sys_get_temp;therm_data->dev_ops.get_mode = th_sys_get_mode;therm_data->dev_ops.get_trip_type = th_sys_get_trip_type;therm_data->dev_ops.get_trip_temp = th_sys_get_trip_temp;therm_data->dev_ops.get_crit_temp = th_sys_get_crit_temp;/** max die temp on imx parts using anatop is 105C, let's give some* cushion for noise and possible temperature rise between measurements.*/therm_data->crit_temp_level = 100000; /* in millicelsius */sd = &therm_data->sensor_data;sd->noise_margin = IMX_ANATOP_TS_NOISE_MARGIN;sd->consec_high_limit = IMX_ANATOP_TS_NOISE_COUNT;sd->anatopmfd = anatopmfd;platform_set_drvdata(pdev, therm_data);ret = anatop_process_ts_fuse_data(fuse_data, therm_data);if (ret) {dev_err(&pdev->dev, "Invalid temperature calibration data.\n");goto err_unregister;}/* Make sure sensor is in known good state for measurements */anatop_write_reg(anatopmfd, HW_ANADIG_TEMPSENSE0, 0,BM_ANADIG_TEMPSENSE0_POWER_DOWN);anatop_write_reg(anatopmfd, HW_ANADIG_TEMPSENSE0, 0,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP);anatop_write_reg(anatopmfd, HW_ANADIG_TEMPSENSE1, 0,BM_ANADIG_TEMPSENSE1_MEASURE_FREQ);anatop_write_reg(anatopmfd, HW_ANADIG_ANA_MISC0_SET,BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF,BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF);anatop_write_reg(anatopmfd, HW_ANADIG_TEMPSENSE0,BM_ANADIG_TEMPSENSE0_POWER_DOWN,BM_ANADIG_TEMPSENSE0_POWER_DOWN);therm_data->tzdev = thermal_zone_device_register("Processor", 1, therm_data, &therm_data->dev_ops, 0, 0, 0,IMX_THERMAL_POLLING_FREQUENCY_MS);if (IS_ERR(therm_data->tzdev)) {dev_err(&pdev->dev,"Failed to register thermal zone device\n");ret = -EINVAL;goto err_unregister;}dev_info(&pdev->dev, "imx thermal management registered\n");return 0;+err_unregister:
anatop_thermal_remove(pdev);return ret;+}
+static struct of_device_id __devinitdata of_anatop_thermal_match_tbl[] = {
{ .compatible = "fsl,anatop-thermal", },{ /* end */ }+};
+static struct platform_driver anatop_thermal = {
.driver = {.name = "anatop_thermal",.owner = THIS_MODULE,.of_match_table = of_anatop_thermal_match_tbl,},.probe = anatop_thermal_probe,.remove = anatop_thermal_remove,.suspend = anatop_thermal_suspend,.resume = anatop_thermal_resume,+};
+static int __devinit anatop_thermal_init(void) +{
return platform_driver_register(&anatop_thermal);+} +device_initcall(anatop_thermal_init);
+static void __exit anatop_thermal_exit(void) +{
platform_driver_unregister(&anatop_thermal);+} +module_exit(anatop_thermal_exit);
+MODULE_AUTHOR("Freescale Semiconductor"); +MODULE_DESCRIPTION("i.MX anatop thermal driver"); +MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:imx-anatop-thermal");
1.7.10
On Tue, Jun 26, 2012 at 11:51:55PM -0500, Robert Lee wrote:
+static inline int anatop_get_temp(int *temp, struct thermal_zone_device *tzdev) +{
- unsigned int n_meas;
- unsigned int reg;
- struct imx_anatop_tsdata *sd;
- sd = &((struct imx_anatop_thdata *)tzdev->devdata)->sensor_data;
- do {
/** Every time we measure the temperature, we will power on the* temperature sensor, enable measurements, take a reading,* disable measurements, power off the temperature sensor.*/sd->handle_suspend = false;anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0,BM_ANADIG_TEMPSENSE0_POWER_DOWN);anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP);/** According to the anatop temp sensor designers, it may require* up to ~17us to complete a measurement (imx6q).* But this timing isn't checked on every part nor is it* specified in the datasheet, so sleeping at least 1ms should* provide plenty of time. Sleeping longer than 1ms is ok so no* need for usleep_range */msleep(1);reg = anatop_read_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0);anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP);anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0,BM_ANADIG_TEMPSENSE0_POWER_DOWN,BM_ANADIG_TEMPSENSE0_POWER_DOWN);- /* if we had a suspend and resume event, we will re-take the reading */
- } while (sd->handle_suspend);
[...]
+static int anatop_thermal_suspend(struct platform_device *pdev,
pm_message_t state)+{
- struct imx_anatop_thdata *dd = platform_get_drvdata(pdev);
- struct imx_anatop_tsdata *sd = &dd->sensor_data;
- /* power off the sensor during suspend */
- anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0,
BM_ANADIG_TEMPSENSE0_MEASURE_TEMP);- anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0,
BM_ANADIG_TEMPSENSE0_POWER_DOWN,BM_ANADIG_TEMPSENSE0_POWER_DOWN);- return 0;
+}
+static int anatop_thermal_resume(struct platform_device *pdev) +{
- struct imx_anatop_thdata *dd = platform_get_drvdata(pdev);
- struct imx_anatop_tsdata *sd = &dd->sensor_data;
- sd->handle_suspend = true;
- return 0;
+}
I don't know how to handle this properly or if it's really needed, but the usage of this handle_suspend variable really looks suspicious. I've never seen a driver looping around a while-suspended-in-between. Someone else should have a look over this.
Sascha
On Wed, Jun 27, 2012 at 8:48 AM, Sascha Hauer s.hauer@pengutronix.de wrote:
On Tue, Jun 26, 2012 at 11:51:55PM -0500, Robert Lee wrote:
+static inline int anatop_get_temp(int *temp, struct thermal_zone_device *tzdev) +{
unsigned int n_meas;unsigned int reg;struct imx_anatop_tsdata *sd;sd = &((struct imx_anatop_thdata *)tzdev->devdata)->sensor_data;do {/** Every time we measure the temperature, we will power on the* temperature sensor, enable measurements, take a reading,* disable measurements, power off the temperature sensor.*/sd->handle_suspend = false;anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0,BM_ANADIG_TEMPSENSE0_POWER_DOWN);anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP);/** According to the anatop temp sensor designers, it may require* up to ~17us to complete a measurement (imx6q).* But this timing isn't checked on every part nor is it* specified in the datasheet, so sleeping at least 1ms should* provide plenty of time. Sleeping longer than 1ms is ok so no* need for usleep_range */msleep(1);reg = anatop_read_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0);anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP);anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0,BM_ANADIG_TEMPSENSE0_POWER_DOWN,BM_ANADIG_TEMPSENSE0_POWER_DOWN);/* if we had a suspend and resume event, we will re-take the reading */} while (sd->handle_suspend);[...]
+static int anatop_thermal_suspend(struct platform_device *pdev,
pm_message_t state)+{
struct imx_anatop_thdata *dd = platform_get_drvdata(pdev);struct imx_anatop_tsdata *sd = &dd->sensor_data;/* power off the sensor during suspend */anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0, 0,BM_ANADIG_TEMPSENSE0_MEASURE_TEMP);anatop_write_reg(sd->anatopmfd, HW_ANADIG_TEMPSENSE0,BM_ANADIG_TEMPSENSE0_POWER_DOWN,BM_ANADIG_TEMPSENSE0_POWER_DOWN);return 0;+}
+static int anatop_thermal_resume(struct platform_device *pdev) +{
struct imx_anatop_thdata *dd = platform_get_drvdata(pdev);struct imx_anatop_tsdata *sd = &dd->sensor_data;sd->handle_suspend = true;return 0;+}
I don't know how to handle this properly or if it's really needed, but the usage of this handle_suspend variable really looks suspicious. I've never seen a driver looping around a while-suspended-in-between. Someone else should have a look over this.
I'll add some more context that may help you and others in analyzing this.
As mentioned, this driver hooks into the linux thermal framework. Upon registration with this is framework, the thermal framework creates a kernel thread which periodically checks the temperature and takes any necessary action. So anatop_get_temp periodically gets called. Now if a suspend were to occur during the msleep() call of this function for example, the temperature read afterword may not be valid. So the loop check can detect that a suspend had occurred and that the temperature sensor value read was invalid so it will try again.
Another option would be for the resume function to return the temperature sensor to its previous state that it was in right before suspend. This would require the resume to re-enable the temperature sensor and spin in a loop waiting for the temperature measurement to complete (aka, checking a hardware bit for completion) which theoretically may take up to ~17us. In this case, a timeout could be added to this loop if we don't trust the hardware, and the looping in the anatop_get_temp could be removed. This function already has some handling if an invalid temp sensor reading is detected.
Sascha
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Rob Lee -
Robert Lee
-
Sascha Hauer