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-rw-r--r--drivers/thermal/Kconfig10
-rw-r--r--drivers/thermal/Makefile1
-rw-r--r--drivers/thermal/thermal-generic-adc.c182
3 files changed, 193 insertions, 0 deletions
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index ee02e6021c94..4166c10ba314 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -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
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 998134ff3b45..10b07c14f8a9 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -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
diff --git a/drivers/thermal/thermal-generic-adc.c b/drivers/thermal/thermal-generic-adc.c
new file mode 100644
index 000000000000..73f55d6a1721
--- /dev/null
+++ b/drivers/thermal/thermal-generic-adc.c
@@ -0,0 +1,182 @@
+/*
+ * 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");