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![Martin Blumenstingl](/assets/img/avatar_default.png)
Since commit d36e2fa025
("thermal: generic-adc: make lookup table
optional") "generic-adc-thermal" can be used with an IIO_TEMP channel.
In this case the following message is logged at probe time:
no lookup table, assuming DAC channel returns milliCelcius
Silence this info message if the channel type is known to be in
milli celsius. Keep this message when the channel type is unknown or not
of type temperature.
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200107232044.889075-3-martin.blumenstingl@googlemail.com
178 lines
4.1 KiB
C
178 lines
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Generic ADC thermal driver
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*
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* Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
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*
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* Author: Laxman Dewangan <ldewangan@nvidia.com>
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*/
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#include <linux/iio/consumer.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/thermal.h>
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struct gadc_thermal_info {
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struct device *dev;
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struct thermal_zone_device *tz_dev;
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struct iio_channel *channel;
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s32 *lookup_table;
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int nlookup_table;
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};
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static int gadc_thermal_adc_to_temp(struct gadc_thermal_info *gti, int val)
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{
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int temp, temp_hi, temp_lo, adc_hi, adc_lo;
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int i;
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if (!gti->lookup_table)
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return val;
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for (i = 0; i < gti->nlookup_table; i++) {
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if (val >= gti->lookup_table[2 * i + 1])
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break;
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}
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if (i == 0) {
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temp = gti->lookup_table[0];
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} else if (i >= gti->nlookup_table) {
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temp = gti->lookup_table[2 * (gti->nlookup_table - 1)];
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} else {
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adc_hi = gti->lookup_table[2 * i - 1];
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adc_lo = gti->lookup_table[2 * i + 1];
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temp_hi = gti->lookup_table[2 * i - 2];
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temp_lo = gti->lookup_table[2 * i];
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temp = temp_hi + mult_frac(temp_lo - temp_hi, val - adc_hi,
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adc_lo - adc_hi);
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}
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return temp;
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}
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static int gadc_thermal_get_temp(void *data, int *temp)
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{
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struct gadc_thermal_info *gti = data;
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int val;
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int ret;
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ret = iio_read_channel_processed(gti->channel, &val);
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if (ret < 0) {
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dev_err(gti->dev, "IIO channel read failed %d\n", ret);
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return ret;
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}
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*temp = gadc_thermal_adc_to_temp(gti, val);
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return 0;
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}
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static const struct thermal_zone_of_device_ops gadc_thermal_ops = {
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.get_temp = gadc_thermal_get_temp,
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};
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static int gadc_thermal_read_linear_lookup_table(struct device *dev,
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struct gadc_thermal_info *gti)
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{
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struct device_node *np = dev->of_node;
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enum iio_chan_type chan_type;
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int ntable;
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int ret;
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ntable = of_property_count_elems_of_size(np, "temperature-lookup-table",
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sizeof(u32));
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if (ntable <= 0) {
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ret = iio_get_channel_type(gti->channel, &chan_type);
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if (ret || chan_type != IIO_TEMP)
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dev_notice(dev,
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"no lookup table, assuming DAC channel returns milliCelcius\n");
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return 0;
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}
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if (ntable % 2) {
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dev_err(dev, "Pair of temperature vs ADC read value missing\n");
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return -EINVAL;
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}
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gti->lookup_table = devm_kcalloc(dev,
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ntable, sizeof(*gti->lookup_table),
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GFP_KERNEL);
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if (!gti->lookup_table)
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return -ENOMEM;
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ret = of_property_read_u32_array(np, "temperature-lookup-table",
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(u32 *)gti->lookup_table, ntable);
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if (ret < 0) {
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dev_err(dev, "Failed to read temperature lookup table: %d\n",
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ret);
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return ret;
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}
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gti->nlookup_table = ntable / 2;
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return 0;
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}
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static int gadc_thermal_probe(struct platform_device *pdev)
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{
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struct gadc_thermal_info *gti;
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int ret;
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if (!pdev->dev.of_node) {
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dev_err(&pdev->dev, "Only DT based supported\n");
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return -ENODEV;
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}
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gti = devm_kzalloc(&pdev->dev, sizeof(*gti), GFP_KERNEL);
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if (!gti)
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return -ENOMEM;
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gti->channel = devm_iio_channel_get(&pdev->dev, "sensor-channel");
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if (IS_ERR(gti->channel)) {
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ret = PTR_ERR(gti->channel);
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if (ret != -EPROBE_DEFER)
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dev_err(&pdev->dev, "IIO channel not found: %d\n", ret);
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return ret;
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}
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ret = gadc_thermal_read_linear_lookup_table(&pdev->dev, gti);
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if (ret < 0)
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return ret;
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gti->dev = &pdev->dev;
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platform_set_drvdata(pdev, gti);
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gti->tz_dev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, gti,
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&gadc_thermal_ops);
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if (IS_ERR(gti->tz_dev)) {
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ret = PTR_ERR(gti->tz_dev);
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if (ret != -EPROBE_DEFER)
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dev_err(&pdev->dev,
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"Thermal zone sensor register failed: %d\n",
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ret);
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return ret;
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}
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return 0;
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}
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static const struct of_device_id of_adc_thermal_match[] = {
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{ .compatible = "generic-adc-thermal", },
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{},
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};
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MODULE_DEVICE_TABLE(of, of_adc_thermal_match);
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static struct platform_driver gadc_thermal_driver = {
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.driver = {
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.name = "generic-adc-thermal",
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.of_match_table = of_adc_thermal_match,
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},
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.probe = gadc_thermal_probe,
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};
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module_platform_driver(gadc_thermal_driver);
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MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
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MODULE_DESCRIPTION("Generic ADC thermal driver using IIO framework with DT");
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MODULE_LICENSE("GPL v2");
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