thermal: generic-adc: Add ADC based thermal sensor driver (b3aef78f) · Commits · 戴 / test

drivers/thermal/Kconfig

+10 −0

Original line number	Diff line number	Diff line
		@@ -411,4 +411,14 @@ config QCOM_SPMI_TEMP_ALARM
		real time die temperature if an ADC is present or an estimate of the
		temperature based upon the over temperature stage value.

		config GENERIC_ADC_THERMAL
		tristate "Generic ADC based thermal sensor"
		depends on IIO
		help
		This enabled a thermal sysfs driver for the temperature sensor
		which is connected to the General Purpose ADC. The ADC channel
		is read via IIO framework and the channel information is provided
		to this driver. This driver reports the temperature by reading ADC
		channel and converts it to temperature based on lookup table.

		endif

drivers/thermal/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -50,3 +50,4 @@ obj-$(CONFIG_ST_THERMAL) += st/
		obj-$(CONFIG_TEGRA_SOCTHERM) += tegra/
		obj-$(CONFIG_HISI_THERMAL) += hisi_thermal.o
		obj-$(CONFIG_MTK_THERMAL) += mtk_thermal.o
		obj-$(CONFIG_GENERIC_ADC_THERMAL) += thermal-generic-adc.o

drivers/thermal/thermal-generic-adc.c

0 → 100644

+182 −0

Original line number	Diff line number	Diff line
		/*
		* Generic ADC thermal driver
		*
		* Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
		*
		* Author: Laxman Dewangan <ldewangan@nvidia.com>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 as
		* published by the Free Software Foundation.
		*/
		#include <linux/iio/consumer.h>
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/platform_device.h>
		#include <linux/slab.h>
		#include <linux/thermal.h>

		struct gadc_thermal_info {
		struct device *dev;
		struct thermal_zone_device *tz_dev;
		struct iio_channel *channel;
		s32 *lookup_table;
		int nlookup_table;
		};

		static int gadc_thermal_adc_to_temp(struct gadc_thermal_info *gti, int val)
		{
		int temp, adc_hi, adc_lo;
		int i;

		for (i = 0; i < gti->nlookup_table; i++) {
		if (val >= gti->lookup_table[2 * i + 1])
		break;
		}

		if (i == 0) {
		temp = gti->lookup_table[0];
		} else if (i >= (gti->nlookup_table - 1)) {
		temp = gti->lookup_table[2 * (gti->nlookup_table - 1)];
		} else {
		adc_hi = gti->lookup_table[2 * i - 1];
		adc_lo = gti->lookup_table[2 * i + 1];
		temp = gti->lookup_table[2 * i];
		temp -= ((val - adc_lo) * 1000) / (adc_hi - adc_lo);
		}

		return temp;
		}

		static int gadc_thermal_get_temp(void data, int temp)
		{
		struct gadc_thermal_info *gti = data;
		int val;
		int ret;

		ret = iio_read_channel_processed(gti->channel, &val);
		if (ret < 0) {
		dev_err(gti->dev, "IIO channel read failed %d\n", ret);
		return ret;
		}
		*temp = gadc_thermal_adc_to_temp(gti, val);

		return 0;
		}

		static const struct thermal_zone_of_device_ops gadc_thermal_ops = {
		.get_temp = gadc_thermal_get_temp,
		};

		static int gadc_thermal_read_linear_lookup_table(struct device *dev,
		struct gadc_thermal_info *gti)
		{
		struct device_node *np = dev->of_node;
		int ntable;
		int ret;

		ntable = of_property_count_elems_of_size(np, "temperature-lookup-table",
		sizeof(u32));
		if (ntable < 0) {
		dev_err(dev, "Lookup table is not provided\n");
		return ntable;
		}

		if (ntable % 2) {
		dev_err(dev, "Pair of temperature vs ADC read value missing\n");
		return -EINVAL;
		}

		gti->lookup_table = devm_kzalloc(dev, sizeof(gti->lookup_table)
		ntable, GFP_KERNEL);
		if (!gti->lookup_table)
		return -ENOMEM;

		ret = of_property_read_u32_array(np, "temperature-lookup-table",
		(u32 *)gti->lookup_table, ntable);
		if (ret < 0) {
		dev_err(dev, "Failed to read temperature lookup table: %d\n",
		ret);
		return ret;
		}

		gti->nlookup_table = ntable / 2;

		return 0;
		}

		static int gadc_thermal_probe(struct platform_device *pdev)
		{
		struct gadc_thermal_info *gti;
		int ret;

		if (!pdev->dev.of_node) {
		dev_err(&pdev->dev, "Only DT based supported\n");
		return -ENODEV;
		}

		gti = devm_kzalloc(&pdev->dev, sizeof(*gti), GFP_KERNEL);
		if (!gti)
		return -ENOMEM;

		ret = gadc_thermal_read_linear_lookup_table(&pdev->dev, gti);
		if (ret < 0)
		return ret;

		gti->dev = &pdev->dev;
		platform_set_drvdata(pdev, gti);

		gti->channel = iio_channel_get(&pdev->dev, "sensor-channel");
		if (IS_ERR(gti->channel)) {
		ret = PTR_ERR(gti->channel);
		dev_err(&pdev->dev, "IIO channel not found: %d\n", ret);
		return ret;
		}

		gti->tz_dev = thermal_zone_of_sensor_register(&pdev->dev, 0,
		gti, &gadc_thermal_ops);
		if (IS_ERR(gti->tz_dev)) {
		ret = PTR_ERR(gti->tz_dev);
		dev_err(&pdev->dev, "Thermal zone sensor register failed: %d\n",
		ret);
		goto sensor_fail;
		}

		return 0;

		sensor_fail:
		iio_channel_release(gti->channel);

		return ret;
		}

		static int gadc_thermal_remove(struct platform_device *pdev)
		{
		struct gadc_thermal_info *gti = platform_get_drvdata(pdev);

		thermal_zone_of_sensor_unregister(&pdev->dev, gti->tz_dev);
		iio_channel_release(gti->channel);

		return 0;
		}

		static const struct of_device_id of_adc_thermal_match[] = {
		{ .compatible = "generic-adc-thermal", },
		{},
		};
		MODULE_DEVICE_TABLE(of, of_adc_thermal_match);

		static struct platform_driver gadc_thermal_driver = {
		.driver = {
		.name = "generic-adc-thermal",
		.of_match_table = of_adc_thermal_match,
		},
		.probe = gadc_thermal_probe,
		.remove = gadc_thermal_remove,
		};

		module_platform_driver(gadc_thermal_driver);

		MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
		MODULE_DESCRIPTION("Generic ADC thermal driver using IIO framework with DT");
		MODULE_LICENSE("GPL v2");

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