[PATCH V3 1/2] thermal: max77620: Add DT binding doc for thermal driver

[PATCH V3 1/2] thermal: max77620: Add DT binding doc for thermal driver

[Laxman Dewangan]

Maxim Semiconductor MAX77620 supports alarm interrupts when
its die temperature crosses 120C and 140C. These threshold
temperatures are not configurable.

Add DT binding document to details out the DT property related
to MAX77620 thermal functionality.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
---
 .../bindings/thermal/thermal-max77620.txt          | 64 ++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/thermal/thermal-max77620.txt

diff --git a/Documentation/devicetree/bindings/thermal/thermal-max77620.txt b/Documentation/devicetree/bindings/thermal/thermal-max77620.txt
new file mode 100644
index 0000000..5a500d5
--- /dev/null
+++ b/Documentation/devicetree/bindings/thermal/thermal-max77620.txt
@@ -0,0 +1,64 @@
+Thermal driver for MAX77620 Power management IC from Maxim Semiconductor.
+
+Maxim Semiconductor MAX77620 supports alarm interrupts when its
+die temperature crosses 120C and 140C. These threshold temperatures
+are not configurable. Device does not provide the real temperature
+of die other than just indicating whether temperature is above or
+below threshold level.
+
+Required properties:
+-------------------
+#thermal-sensor-cells:	Please refer <devicetree/bindings/thermal/thermal.txt>
+			for more details.
+			The value must be 0.
+
+For more details, please refer generic thermal DT binding document
+<devicetree/bindings/thermal/thermal.txt>.
+
+Please refer <devicetree/bindings/mfd/max77620.txt> for mfd DT binding
+document for the MAX77620.
+
+Example:
+--------
+#include <dt-bindings/mfd/max77620.h>
+#include <dt-bindings/thermal/thermal.h>
+...
+
+i2c@7000d000 {
+	spmic: max77620@3c {
+		compatible = "maxim,max77620";
+		:::::
+		#thermal-sensor-cells = <0>;
+		:::
+	};
+};
+
+cool_dev: cool-dev {
+	compatible = "cooling-dev";
+	#cooling-cells = <2>;
+};
+
+thermal-zones {
+	PMIC-Die {
+		polling-delay = <0>;
+		polling-delay-passive = <0>;
+		thermal-sensors = <&spmic>;
+
+		trips {
+			die_temp_thresh: hot-die {
+				temperature = <120000>;
+				type = "active";
+				hysteresis = <0>;
+			};
+		};
+
+		cooling-maps {
+			map0 {
+				trip = <&die_temp_thresh>;
+				cooling-device = <&cool_dev THERMAL_NO_LIMIT
+						  THERMAL_NO_LIMIT>;
+				contribution = <100>;
+			};
+		};
+	};
+};
-- 
2.1.4

[PATCH V3 2/2] thermal: max77620: Add thermal driver for reporting junction temp

[Laxman Dewangan]

Maxim Semiconductor Max77620 supports alarm interrupts when
its die temperature crosses 120C and 140C. These threshold
temperatures are not configurable.

Add thermal driver to register PMIC die temperature as thermal
zone sensor and capture the die temperature warning interrupts
to notifying the client.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
---
The patch was sent earlier but dependent mfd header file was not available on
tree and hence it was not applied.
The mfd patches are in rc-4.7 and hence resending again this patch.


 drivers/thermal/Kconfig            |  10 +++
 drivers/thermal/Makefile           |   1 +
 drivers/thermal/thermal-max77620.c | 151 +++++++++++++++++++++++++++++++++++++
 3 files changed, 162 insertions(+)
 create mode 100644 drivers/thermal/thermal-max77620.c

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 2d702ca..a2b4433 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -195,6 +195,16 @@ config IMX_THERMAL
 	  cpufreq is used as the cooling device to throttle CPUs when the
 	  passive trip is crossed.
 
+config MAX77620_THERMAL
+	tristate "Temperature sensor driver for Maxim MAX77620 PMIC"
+	depends on MFD_MAX77620
+	depends on OF
+	help
+	  Support for die junction temperature warning alarm for Maxim
+	  Semiconductor PMIC MAX77620 device. Device generates two alarm
+	  interrupts when PMIC die temperature cross the threshold of
+	  120 degC and 140 degC.
+
 config SPEAR_THERMAL
 	tristate "SPEAr thermal sensor driver"
 	depends on PLAT_SPEAR || COMPILE_TEST
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 10b07c1..90e1d7e 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_DB8500_THERMAL)	+= db8500_thermal.o
 obj-$(CONFIG_ARMADA_THERMAL)	+= armada_thermal.o
 obj-$(CONFIG_TANGO_THERMAL)	+= tango_thermal.o
 obj-$(CONFIG_IMX_THERMAL)	+= imx_thermal.o
+obj-$(CONFIG_MAX77620_THERMAL)	+= thermal-max77620.o
 obj-$(CONFIG_DB8500_CPUFREQ_COOLING)	+= db8500_cpufreq_cooling.o
 obj-$(CONFIG_INTEL_POWERCLAMP)	+= intel_powerclamp.o
 obj-$(CONFIG_X86_PKG_TEMP_THERMAL)	+= x86_pkg_temp_thermal.o
diff --git a/drivers/thermal/thermal-max77620.c b/drivers/thermal/thermal-max77620.c
new file mode 100644
index 0000000..e4ed82a
--- /dev/null
+++ b/drivers/thermal/thermal-max77620.c
@@ -0,0 +1,151 @@
+/*
+ * Junction temperature thermal driver for Maxim Max77620.
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Author: Laxman Dewangan <ldewangan@nvidia.com>
+ *	   Mallikarjun Kasoju <mkasoju@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/max77620.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+
+#define MAX77620_NORMAL_OPERATING_TEMP	100000
+#define MAX77620_TJALARM1_TEMP		120000
+#define MAX77620_TJALARM2_TEMP		140000
+
+struct max77620_therm_info {
+	struct device			*dev;
+	struct regmap			*rmap;
+	struct thermal_zone_device	*tz_device;
+	int				irq_tjalarm1;
+	int				irq_tjalarm2;
+};
+
+static int max77620_thermal_read_temp(void *data, int *temp)
+{
+	struct max77620_therm_info *mtherm = data;
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(mtherm->rmap, MAX77620_REG_STATLBT, &val);
+	if (ret < 0) {
+		dev_err(mtherm->dev, "Failed to read STATLBT: %d\n", ret);
+		return -EINVAL;
+	}
+
+	if (val & MAX77620_IRQ_TJALRM2_MASK)
+		*temp = MAX77620_TJALARM2_TEMP;
+	else if (val & MAX77620_IRQ_TJALRM1_MASK)
+		*temp = MAX77620_TJALARM1_TEMP;
+	else
+		*temp = MAX77620_NORMAL_OPERATING_TEMP;
+
+	return 0;
+}
+
+static const struct thermal_zone_of_device_ops max77620_thermal_ops = {
+	.get_temp = max77620_thermal_read_temp,
+};
+
+static irqreturn_t max77620_thermal_irq(int irq, void *data)
+{
+	struct max77620_therm_info *mtherm = data;
+
+	if (irq == mtherm->irq_tjalarm1)
+		dev_warn(mtherm->dev, "Junction Temp Alarm1(120C) occurred\n");
+	else if (irq == mtherm->irq_tjalarm2)
+		dev_warn(mtherm->dev, "Junction Temp Alarm2(140C) occurred\n");
+
+	thermal_zone_device_update(mtherm->tz_device);
+
+	return IRQ_HANDLED;
+}
+
+static int max77620_thermal_probe(struct platform_device *pdev)
+{
+	struct max77620_therm_info *mtherm;
+	int ret;
+
+	pdev->dev.of_node = pdev->dev.parent->of_node;
+
+	mtherm = devm_kzalloc(&pdev->dev, sizeof(*mtherm), GFP_KERNEL);
+	if (!mtherm)
+		return -ENOMEM;
+
+	mtherm->irq_tjalarm1 = platform_get_irq(pdev, 0);
+	mtherm->irq_tjalarm2 = platform_get_irq(pdev, 1);
+	if ((mtherm->irq_tjalarm1 < 0) || (mtherm->irq_tjalarm2 < 0)) {
+		dev_err(&pdev->dev, "Alarm irq number not available\n");
+		return -EINVAL;
+	}
+
+	mtherm->dev = &pdev->dev;
+	mtherm->rmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!mtherm->rmap) {
+		dev_err(&pdev->dev, "Failed to get parent regmap\n");
+		return -ENODEV;
+	}
+
+	mtherm->tz_device = devm_thermal_zone_of_sensor_register(&pdev->dev, 0,
+				mtherm, &max77620_thermal_ops);
+	if (IS_ERR(mtherm->tz_device)) {
+		ret = PTR_ERR(mtherm->tz_device);
+		dev_err(&pdev->dev, "Failed to register thermal zone: %d\n",
+			ret);
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(&pdev->dev, mtherm->irq_tjalarm1, NULL,
+					max77620_thermal_irq,
+					IRQF_ONESHOT | IRQF_SHARED,
+					dev_name(&pdev->dev), mtherm);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to request irq1: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(&pdev->dev, mtherm->irq_tjalarm2, NULL,
+					max77620_thermal_irq,
+					IRQF_ONESHOT | IRQF_SHARED,
+					dev_name(&pdev->dev), mtherm);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to request irq2: %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, mtherm);
+
+	return 0;
+}
+
+static struct platform_device_id max77620_thermal_devtype[] = {
+	{ .name = "max77620-thermal", },
+	{},
+};
+
+static struct platform_driver max77620_thermal_driver = {
+	.driver = {
+		.name = "max77620-thermal",
+	},
+	.probe = max77620_thermal_probe,
+	.id_table = max77620_thermal_devtype,
+};
+
+module_platform_driver(max77620_thermal_driver);
+
+MODULE_DESCRIPTION("Max77620 Junction temperature Thermal driver");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_AUTHOR("Mallikarjun Kasoju <mkasoju@nvidia.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.1.4

Re: [PATCH V3 2/2] thermal: max77620: Add thermal driver for reporting junction temp

[Keerthy]

Hi Laxman,

On Monday 06 June 2016 05:14 PM, Laxman Dewangan wrote:
> Maxim Semiconductor Max77620 supports alarm interrupts when
> its die temperature crosses 120C and 140C. These threshold
> temperatures are not configurable.
>
> Add thermal driver to register PMIC die temperature as thermal
> zone sensor and capture the die temperature warning interrupts
> to notifying the client.

Couple of minor comments.

>
> Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
> ---
> The patch was sent earlier but dependent mfd header file was not available on
> tree and hence it was not applied.
> The mfd patches are in rc-4.7 and hence resending again this patch.
>
>
>   drivers/thermal/Kconfig            |  10 +++
>   drivers/thermal/Makefile           |   1 +
>   drivers/thermal/thermal-max77620.c | 151 +++++++++++++++++++++++++++++++++++++
>   3 files changed, 162 insertions(+)
>   create mode 100644 drivers/thermal/thermal-max77620.c
>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 2d702ca..a2b4433 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -195,6 +195,16 @@ config IMX_THERMAL
>   	  cpufreq is used as the cooling device to throttle CPUs when the
>   	  passive trip is crossed.
>
> +config MAX77620_THERMAL
> +	tristate "Temperature sensor driver for Maxim MAX77620 PMIC"
> +	depends on MFD_MAX77620
> +	depends on OF
> +	help
> +	  Support for die junction temperature warning alarm for Maxim
> +	  Semiconductor PMIC MAX77620 device. Device generates two alarm
> +	  interrupts when PMIC die temperature cross the threshold of
> +	  120 degC and 140 degC.

So what are the actions taken for 120C and 140C trips?
What cooling device is used?

> +
>   config SPEAR_THERMAL
>   	tristate "SPEAr thermal sensor driver"
>   	depends on PLAT_SPEAR || COMPILE_TEST
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 10b07c1..90e1d7e 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -37,6 +37,7 @@ obj-$(CONFIG_DB8500_THERMAL)	+= db8500_thermal.o
>   obj-$(CONFIG_ARMADA_THERMAL)	+= armada_thermal.o
>   obj-$(CONFIG_TANGO_THERMAL)	+= tango_thermal.o
>   obj-$(CONFIG_IMX_THERMAL)	+= imx_thermal.o
> +obj-$(CONFIG_MAX77620_THERMAL)	+= thermal-max77620.o
>   obj-$(CONFIG_DB8500_CPUFREQ_COOLING)	+= db8500_cpufreq_cooling.o
>   obj-$(CONFIG_INTEL_POWERCLAMP)	+= intel_powerclamp.o
>   obj-$(CONFIG_X86_PKG_TEMP_THERMAL)	+= x86_pkg_temp_thermal.o
> diff --git a/drivers/thermal/thermal-max77620.c b/drivers/thermal/thermal-max77620.c
> new file mode 100644
> index 0000000..e4ed82a
> --- /dev/null
> +++ b/drivers/thermal/thermal-max77620.c
> @@ -0,0 +1,151 @@
> +/*
> + * Junction temperature thermal driver for Maxim Max77620.
> + *
> + * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
> + *
> + * Author: Laxman Dewangan <ldewangan@nvidia.com>
> + *	   Mallikarjun Kasoju <mkasoju@nvidia.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + */
> +
> +#include <linux/irq.h>
> +#include <linux/interrupt.h>
> +#include <linux/mfd/max77620.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/thermal.h>
> +
> +#define MAX77620_NORMAL_OPERATING_TEMP	100000
> +#define MAX77620_TJALARM1_TEMP		120000
> +#define MAX77620_TJALARM2_TEMP		140000
> +
> +struct max77620_therm_info {
> +	struct device			*dev;
> +	struct regmap			*rmap;
> +	struct thermal_zone_device	*tz_device;
> +	int				irq_tjalarm1;
> +	int				irq_tjalarm2;
> +};
> +

This does not give the absolute temperature. So some comments would be 
really helpful for this function.

> +static int max77620_thermal_read_temp(void *data, int *temp)
> +{
> +	struct max77620_therm_info *mtherm = data;
> +	unsigned int val;
> +	int ret;
> +
> +	ret = regmap_read(mtherm->rmap, MAX77620_REG_STATLBT, &val);
> +	if (ret < 0) {
> +		dev_err(mtherm->dev, "Failed to read STATLBT: %d\n", ret);
> +		return -EINVAL;
> +	}
> +
> +	if (val & MAX77620_IRQ_TJALRM2_MASK)
> +		*temp = MAX77620_TJALARM2_TEMP;
> +	else if (val & MAX77620_IRQ_TJALRM1_MASK)
> +		*temp = MAX77620_TJALARM1_TEMP;
> +	else
> +		*temp = MAX77620_NORMAL_OPERATING_TEMP;
> +
> +	return 0;
> +}
> +
> +static const struct thermal_zone_of_device_ops max77620_thermal_ops = {
> +	.get_temp = max77620_thermal_read_temp,
> +};
> +
> +static irqreturn_t max77620_thermal_irq(int irq, void *data)
> +{
> +	struct max77620_therm_info *mtherm = data;
> +
> +	if (irq == mtherm->irq_tjalarm1)
> +		dev_warn(mtherm->dev, "Junction Temp Alarm1(120C) occurred\n");
> +	else if (irq == mtherm->irq_tjalarm2)
> +		dev_warn(mtherm->dev, "Junction Temp Alarm2(140C) occurred\n");
> +
> +	thermal_zone_device_update(mtherm->tz_device);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int max77620_thermal_probe(struct platform_device *pdev)
> +{
> +	struct max77620_therm_info *mtherm;
> +	int ret;
> +
> +	pdev->dev.of_node = pdev->dev.parent->of_node;
> +
> +	mtherm = devm_kzalloc(&pdev->dev, sizeof(*mtherm), GFP_KERNEL);
> +	if (!mtherm)
> +		return -ENOMEM;
> +
> +	mtherm->irq_tjalarm1 = platform_get_irq(pdev, 0);
> +	mtherm->irq_tjalarm2 = platform_get_irq(pdev, 1);
> +	if ((mtherm->irq_tjalarm1 < 0) || (mtherm->irq_tjalarm2 < 0)) {
> +		dev_err(&pdev->dev, "Alarm irq number not available\n");
> +		return -EINVAL;
> +	}
> +
> +	mtherm->dev = &pdev->dev;
> +	mtherm->rmap = dev_get_regmap(pdev->dev.parent, NULL);
> +	if (!mtherm->rmap) {
> +		dev_err(&pdev->dev, "Failed to get parent regmap\n");
> +		return -ENODEV;
> +	}
> +
> +	mtherm->tz_device = devm_thermal_zone_of_sensor_register(&pdev->dev, 0,
> +				mtherm, &max77620_thermal_ops);
> +	if (IS_ERR(mtherm->tz_device)) {
> +		ret = PTR_ERR(mtherm->tz_device);
> +		dev_err(&pdev->dev, "Failed to register thermal zone: %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	ret = devm_request_threaded_irq(&pdev->dev, mtherm->irq_tjalarm1, NULL,
> +					max77620_thermal_irq,
> +					IRQF_ONESHOT | IRQF_SHARED,
> +					dev_name(&pdev->dev), mtherm);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "Failed to request irq1: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = devm_request_threaded_irq(&pdev->dev, mtherm->irq_tjalarm2, NULL,
> +					max77620_thermal_irq,
> +					IRQF_ONESHOT | IRQF_SHARED,
> +					dev_name(&pdev->dev), mtherm);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "Failed to request irq2: %d\n", ret);
> +		return ret;
> +	}
> +
> +	platform_set_drvdata(pdev, mtherm);
> +
> +	return 0;
> +}
> +
> +static struct platform_device_id max77620_thermal_devtype[] = {
> +	{ .name = "max77620-thermal", },
> +	{},
> +};
> +
> +static struct platform_driver max77620_thermal_driver = {
> +	.driver = {
> +		.name = "max77620-thermal",
> +	},
> +	.probe = max77620_thermal_probe,
> +	.id_table = max77620_thermal_devtype,
> +};
> +
> +module_platform_driver(max77620_thermal_driver);
> +
> +MODULE_DESCRIPTION("Max77620 Junction temperature Thermal driver");
> +MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
> +MODULE_AUTHOR("Mallikarjun Kasoju <mkasoju@nvidia.com>");
> +MODULE_LICENSE("GPL v2");
>

Re: [PATCH V3 1/2] thermal: max77620: Add DT binding doc for thermal driver

[Keerthy]

On Monday 06 June 2016 05:14 PM, Laxman Dewangan wrote:
> Maxim Semiconductor MAX77620 supports alarm interrupts when
> its die temperature crosses 120C and 140C. These threshold
> temperatures are not configurable.
>
> Add DT binding document to details out the DT property related
> to MAX77620 thermal functionality.
>
> Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
> ---
>   .../bindings/thermal/thermal-max77620.txt          | 64 ++++++++++++++++++++++
>   1 file changed, 64 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/thermal/thermal-max77620.txt
>
> diff --git a/Documentation/devicetree/bindings/thermal/thermal-max77620.txt b/Documentation/devicetree/bindings/thermal/thermal-max77620.txt
> new file mode 100644
> index 0000000..5a500d5
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/thermal/thermal-max77620.txt
> @@ -0,0 +1,64 @@
> +Thermal driver for MAX77620 Power management IC from Maxim Semiconductor.
> +
> +Maxim Semiconductor MAX77620 supports alarm interrupts when its
> +die temperature crosses 120C and 140C. These threshold temperatures
> +are not configurable. Device does not provide the real temperature
> +of die other than just indicating whether temperature is above or
> +below threshold level.
> +
> +Required properties:
> +-------------------
> +#thermal-sensor-cells:	Please refer <devicetree/bindings/thermal/thermal.txt>
> +			for more details.
> +			The value must be 0.
> +
> +For more details, please refer generic thermal DT binding document
> +<devicetree/bindings/thermal/thermal.txt>.
> +
> +Please refer <devicetree/bindings/mfd/max77620.txt> for mfd DT binding
> +document for the MAX77620.
> +
> +Example:
> +--------
> +#include <dt-bindings/mfd/max77620.h>
> +#include <dt-bindings/thermal/thermal.h>
> +...
> +
> +i2c@7000d000 {
> +	spmic: max77620@3c {
> +		compatible = "maxim,max77620";
> +		:::::
> +		#thermal-sensor-cells = <0>;
> +		:::
> +	};
> +};
> +
> +cool_dev: cool-dev {
> +	compatible = "cooling-dev";
> +	#cooling-cells = <2>;
> +};
> +
> +thermal-zones {
> +	PMIC-Die {
> +		polling-delay = <0>;
> +		polling-delay-passive = <0>;
> +		thermal-sensors = <&spmic>;
> +
> +		trips {
> +			die_temp_thresh: hot-die {
> +				temperature = <120000>;
> +				type = "active";
> +				hysteresis = <0>;
> +			};
> +		};

What about 140C? Isn't that a critical trip point?

> +
> +		cooling-maps {
> +			map0 {
> +				trip = <&die_temp_thresh>;
> +				cooling-device = <&cool_dev THERMAL_NO_LIMIT
> +						  THERMAL_NO_LIMIT>;
> +				contribution = <100>;
> +			};
> +		};
> +	};
> +};
>

Re: [PATCH V3 2/2] thermal: max77620: Add thermal driver for reporting junction temp

[Laxman Dewangan]

On Tuesday 07 June 2016 09:18 AM, Keerthy wrote:
> Hi Laxman,
>
> On Monday 06 June 2016 05:14 PM, Laxman Dewangan wrote:
>> Maxim Semiconductor Max77620 supports alarm interrupts when
>> its die temperature crosses 120C and 140C. These threshold
>> temperatures are not configurable.
>>
>> Add thermal driver to register PMIC die temperature as thermal
>> zone sensor and capture the die temperature warning interrupts
>> to notifying the client.
>
> Couple of minor comments.
>
>> +      Support for die junction temperature warning alarm for Maxim
>> +      Semiconductor PMIC MAX77620 device. Device generates two alarm
>> +      interrupts when PMIC die temperature cross the threshold of
>> +      120 degC and 140 degC.
>
> So what are the actions taken for 120C and 140C trips?
> What cooling device is used?
>

The PMIC die temp increases because of higher load on the rails. The 
higher load (more current from rail) is due to if CPU are running on 
higher frequency,

The information is used by the thermal monitoring and throttling system 
and when it sees higher temp on the PMIC die:
- It can reduce the frequency of the CPU or something like this as part 
of thermal throttling.
- If device supports fan then it can increase speed of fans or turn on fan.


>>
>> +};
>> +
>
> This does not give the absolute temperature. So some comments would be 
> really helpful for this function.
>

OK, will add on next rev of patch.

Re: [PATCH V3 1/2] thermal: max77620: Add DT binding doc for thermal driver

[Laxman Dewangan]

On Tuesday 07 June 2016 09:25 AM, Keerthy wrote:
>
>
> On Monday 06 June 2016 05:14 PM, Laxman Dewangan wrote:
>> Maxim Semiconductor MAX77620 supports alarm interrupts when
>> its die temperature crosses 120C and 140C. These threshold
>> temperatures are not configurable.
>>
>> Add DT binding document to details out the DT property related
>> to MAX77620 thermal functionality.
>>
>> Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
>> ---
>>   .../bindings/thermal/thermal-max77620.txt          | 64 
>> ++++++++++++++++++++++
>>   1 file changed, 64 insertions(+)
>>   create mode 100644 
>> Documentation/devicetree/bindings/thermal/thermal-max77620.txt
>>
>> diff --git 
>> a/Documentation/devicetree/bindings/thermal/thermal-max77620.txt 
>> b/Documentation/devicetree/bindings/thermal/thermal-max77620.txt
>> new file mode 100644
>> index 0000000..5a500d5
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/thermal/thermal-max77620.txt
>> @@ -0,0 +1,64 @@
>> +Thermal driver for MAX77620 Power management IC from Maxim 
>> Semiconductor.
>> +
>> +Maxim Semiconductor MAX77620 supports alarm interrupts when its
>> +die temperature crosses 120C and 140C. These threshold temperatures
>> +are not configurable. Device does not provide the real temperature
>> +of die other than just indicating whether temperature is above or
>> +below threshold level.
>> +
>> +Required properties:
>> +-------------------
>> +#thermal-sensor-cells:    Please refer 
>> <devicetree/bindings/thermal/thermal.txt>
>> +            for more details.
>> +            The value must be 0.
>> +
>> +For more details, please refer generic thermal DT binding document
>> +<devicetree/bindings/thermal/thermal.txt>.
>> +
>> +Please refer <devicetree/bindings/mfd/max77620.txt> for mfd DT binding
>> +document for the MAX77620.
>> +
>> +Example:
>> +--------
>> +#include <dt-bindings/mfd/max77620.h>
>> +#include <dt-bindings/thermal/thermal.h>
>> +...
>> +
>> +i2c@7000d000 {
>> +    spmic: max77620@3c {
>> +        compatible = "maxim,max77620";
>> +        :::::
>> +        #thermal-sensor-cells = <0>;
>> +        :::
>> +    };
>> +};
>> +
>> +cool_dev: cool-dev {
>> +    compatible = "cooling-dev";
>> +    #cooling-cells = <2>;
>> +};
>> +
>> +thermal-zones {
>> +    PMIC-Die {
>> +        polling-delay = <0>;
>> +        polling-delay-passive = <0>;
>> +        thermal-sensors = <&spmic>;
>> +
>> +        trips {
>> +            die_temp_thresh: hot-die {
>> +                temperature = <120000>;
>> +                type = "active";
>> +                hysteresis = <0>;
>> +            };
>> +        };
>
> What about 140C? Isn't that a critical trip point?

Yes, it is there and it can be populated/extended on the same way and 
handled.

This is just an example.


>
>> +
>> +        cooling-maps {
>> +            map0 {
>> +                trip = <&die_temp_thresh>;
>> +                cooling-device = <&cool_dev THERMAL_NO_LIMIT
>> +                          THERMAL_NO_LIMIT>;
>> +                contribution = <100>;
>> +            };
>> +        };
>> +    };
>> +};
>>

Re: [PATCH V3 1/2] thermal: max77620: Add DT binding doc for thermal driver

[Keerthy]

On Tuesday 07 June 2016 12:08 PM, Laxman Dewangan wrote:
>
> On Tuesday 07 June 2016 09:25 AM, Keerthy wrote:
>>
>>
>> On Monday 06 June 2016 05:14 PM, Laxman Dewangan wrote:
>>> Maxim Semiconductor MAX77620 supports alarm interrupts when
>>> its die temperature crosses 120C and 140C. These threshold
>>> temperatures are not configurable.
>>>
>>> Add DT binding document to details out the DT property related
>>> to MAX77620 thermal functionality.
>>>
>>> Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
>>> ---
>>>   .../bindings/thermal/thermal-max77620.txt          | 64
>>> ++++++++++++++++++++++
>>>   1 file changed, 64 insertions(+)
>>>   create mode 100644
>>> Documentation/devicetree/bindings/thermal/thermal-max77620.txt
>>>
>>> diff --git
>>> a/Documentation/devicetree/bindings/thermal/thermal-max77620.txt
>>> b/Documentation/devicetree/bindings/thermal/thermal-max77620.txt
>>> new file mode 100644
>>> index 0000000..5a500d5
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/thermal/thermal-max77620.txt
>>> @@ -0,0 +1,64 @@
>>> +Thermal driver for MAX77620 Power management IC from Maxim
>>> Semiconductor.
>>> +
>>> +Maxim Semiconductor MAX77620 supports alarm interrupts when its
>>> +die temperature crosses 120C and 140C. These threshold temperatures
>>> +are not configurable. Device does not provide the real temperature
>>> +of die other than just indicating whether temperature is above or
>>> +below threshold level.
>>> +
>>> +Required properties:
>>> +-------------------
>>> +#thermal-sensor-cells:    Please refer
>>> <devicetree/bindings/thermal/thermal.txt>
>>> +            for more details.
>>> +            The value must be 0.
>>> +
>>> +For more details, please refer generic thermal DT binding document
>>> +<devicetree/bindings/thermal/thermal.txt>.
>>> +
>>> +Please refer <devicetree/bindings/mfd/max77620.txt> for mfd DT binding
>>> +document for the MAX77620.
>>> +
>>> +Example:
>>> +--------
>>> +#include <dt-bindings/mfd/max77620.h>
>>> +#include <dt-bindings/thermal/thermal.h>
>>> +...
>>> +
>>> +i2c@7000d000 {
>>> +    spmic: max77620@3c {
>>> +        compatible = "maxim,max77620";
>>> +        :::::
>>> +        #thermal-sensor-cells = <0>;
>>> +        :::
>>> +    };
>>> +};
>>> +
>>> +cool_dev: cool-dev {
>>> +    compatible = "cooling-dev";
>>> +    #cooling-cells = <2>;
>>> +};
>>> +
>>> +thermal-zones {
>>> +    PMIC-Die {
>>> +        polling-delay = <0>;
>>> +        polling-delay-passive = <0>;
>>> +        thermal-sensors = <&spmic>;
>>> +
>>> +        trips {
>>> +            die_temp_thresh: hot-die {
>>> +                temperature = <120000>;
>>> +                type = "active";
>>> +                hysteresis = <0>;
>>> +            };
>>> +        };
>>
>> What about 140C? Isn't that a critical trip point?
>
> Yes, it is there and it can be populated/extended on the same way and
> handled.
>
> This is just an example.

Yes i understand that. My question was more w.r.t different types of 
critical points. As i can see 120C is an active trip point.

140C will be a critical trip point and system will have to be shutdown 
right? IMHO you can add that to the example as well since its pretty 
different than the above active trip point.

- Keerthy

>
>
>>
>>> +
>>> +        cooling-maps {
>>> +            map0 {
>>> +                trip = <&die_temp_thresh>;
>>> +                cooling-device = <&cool_dev THERMAL_NO_LIMIT
>>> +                          THERMAL_NO_LIMIT>;
>>> +                contribution = <100>;
>>> +            };
>>> +        };
>>> +    };
>>> +};
>>>
>