cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

thermal-generic-adc.c (4219B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Generic ADC thermal driver
      4 *
      5 * Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
      6 *
      7 * Author: Laxman Dewangan <ldewangan@nvidia.com>
      8 */
      9#include <linux/iio/consumer.h>
     10#include <linux/kernel.h>
     11#include <linux/module.h>
     12#include <linux/platform_device.h>
     13#include <linux/slab.h>
     14#include <linux/thermal.h>
     15
     16struct gadc_thermal_info {
     17	struct device *dev;
     18	struct thermal_zone_device *tz_dev;
     19	struct iio_channel *channel;
     20	s32 *lookup_table;
     21	int nlookup_table;
     22};
     23
     24static int gadc_thermal_adc_to_temp(struct gadc_thermal_info *gti, int val)
     25{
     26	int temp, temp_hi, temp_lo, adc_hi, adc_lo;
     27	int i;
     28
     29	if (!gti->lookup_table)
     30		return val;
     31
     32	for (i = 0; i < gti->nlookup_table; i++) {
     33		if (val >= gti->lookup_table[2 * i + 1])
     34			break;
     35	}
     36
     37	if (i == 0) {
     38		temp = gti->lookup_table[0];
     39	} else if (i >= gti->nlookup_table) {
     40		temp = gti->lookup_table[2 * (gti->nlookup_table - 1)];
     41	} else {
     42		adc_hi = gti->lookup_table[2 * i - 1];
     43		adc_lo = gti->lookup_table[2 * i + 1];
     44
     45		temp_hi = gti->lookup_table[2 * i - 2];
     46		temp_lo = gti->lookup_table[2 * i];
     47
     48		temp = temp_hi + mult_frac(temp_lo - temp_hi, val - adc_hi,
     49					   adc_lo - adc_hi);
     50	}
     51
     52	return temp;
     53}
     54
     55static int gadc_thermal_get_temp(void *data, int *temp)
     56{
     57	struct gadc_thermal_info *gti = data;
     58	int val;
     59	int ret;
     60
     61	ret = iio_read_channel_processed(gti->channel, &val);
     62	if (ret < 0) {
     63		dev_err(gti->dev, "IIO channel read failed %d\n", ret);
     64		return ret;
     65	}
     66	*temp = gadc_thermal_adc_to_temp(gti, val);
     67
     68	return 0;
     69}
     70
     71static const struct thermal_zone_of_device_ops gadc_thermal_ops = {
     72	.get_temp = gadc_thermal_get_temp,
     73};
     74
     75static int gadc_thermal_read_linear_lookup_table(struct device *dev,
     76						 struct gadc_thermal_info *gti)
     77{
     78	struct device_node *np = dev->of_node;
     79	enum iio_chan_type chan_type;
     80	int ntable;
     81	int ret;
     82
     83	ntable = of_property_count_elems_of_size(np, "temperature-lookup-table",
     84						 sizeof(u32));
     85	if (ntable <= 0) {
     86		ret = iio_get_channel_type(gti->channel, &chan_type);
     87		if (ret || chan_type != IIO_TEMP)
     88			dev_notice(dev,
     89				   "no lookup table, assuming DAC channel returns milliCelcius\n");
     90		return 0;
     91	}
     92
     93	if (ntable % 2) {
     94		dev_err(dev, "Pair of temperature vs ADC read value missing\n");
     95		return -EINVAL;
     96	}
     97
     98	gti->lookup_table = devm_kcalloc(dev,
     99					 ntable, sizeof(*gti->lookup_table),
    100					 GFP_KERNEL);
    101	if (!gti->lookup_table)
    102		return -ENOMEM;
    103
    104	ret = of_property_read_u32_array(np, "temperature-lookup-table",
    105					 (u32 *)gti->lookup_table, ntable);
    106	if (ret < 0) {
    107		dev_err(dev, "Failed to read temperature lookup table: %d\n",
    108			ret);
    109		return ret;
    110	}
    111
    112	gti->nlookup_table = ntable / 2;
    113
    114	return 0;
    115}
    116
    117static int gadc_thermal_probe(struct platform_device *pdev)
    118{
    119	struct gadc_thermal_info *gti;
    120	int ret;
    121
    122	if (!pdev->dev.of_node) {
    123		dev_err(&pdev->dev, "Only DT based supported\n");
    124		return -ENODEV;
    125	}
    126
    127	gti = devm_kzalloc(&pdev->dev, sizeof(*gti), GFP_KERNEL);
    128	if (!gti)
    129		return -ENOMEM;
    130
    131	gti->channel = devm_iio_channel_get(&pdev->dev, "sensor-channel");
    132	if (IS_ERR(gti->channel)) {
    133		ret = PTR_ERR(gti->channel);
    134		if (ret != -EPROBE_DEFER)
    135			dev_err(&pdev->dev, "IIO channel not found: %d\n", ret);
    136		return ret;
    137	}
    138
    139	ret = gadc_thermal_read_linear_lookup_table(&pdev->dev, gti);
    140	if (ret < 0)
    141		return ret;
    142
    143	gti->dev = &pdev->dev;
    144	platform_set_drvdata(pdev, gti);
    145
    146	gti->tz_dev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, gti,
    147							   &gadc_thermal_ops);
    148	if (IS_ERR(gti->tz_dev)) {
    149		ret = PTR_ERR(gti->tz_dev);
    150		if (ret != -EPROBE_DEFER)
    151			dev_err(&pdev->dev,
    152				"Thermal zone sensor register failed: %d\n",
    153				ret);
    154		return ret;
    155	}
    156
    157	return 0;
    158}
    159
    160static const struct of_device_id of_adc_thermal_match[] = {
    161	{ .compatible = "generic-adc-thermal", },
    162	{},
    163};
    164MODULE_DEVICE_TABLE(of, of_adc_thermal_match);
    165
    166static struct platform_driver gadc_thermal_driver = {
    167	.driver = {
    168		.name = "generic-adc-thermal",
    169		.of_match_table = of_adc_thermal_match,
    170	},
    171	.probe = gadc_thermal_probe,
    172};
    173
    174module_platform_driver(gadc_thermal_driver);
    175
    176MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
    177MODULE_DESCRIPTION("Generic ADC thermal driver using IIO framework with DT");
    178MODULE_LICENSE("GPL v2");