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178 lines
4.1 KiB
178 lines
4.1 KiB
// 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 <[email protected]> |
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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 <[email protected]>"); |
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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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