[mirror_ubuntu-hirsute-kernel.git] / drivers / thermal / thermal-generic-adc.c

/*
 * 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_kcalloc(dev,
					 ntable, sizeof(*gti->lookup_table),
					 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 = devm_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 = devm_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);
		return ret;
	}

	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,
};

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");
Commit	Line	Data
b3aef78f LD	1	/*
	2	* Generic ADC thermal driver
	3	*
	4	* Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
	5	*
	6	* Author: Laxman Dewangan <ldewangan@nvidia.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12	#include <linux/iio/consumer.h>
	13	#include <linux/kernel.h>
	14	#include <linux/module.h>
	15	#include <linux/platform_device.h>
	16	#include <linux/slab.h>
	17	#include <linux/thermal.h>
	18
	19	struct gadc_thermal_info {
	20	struct device *dev;
	21	struct thermal_zone_device *tz_dev;
	22	struct iio_channel *channel;
	23	s32 *lookup_table;
	24	int nlookup_table;
	25	};
	26
	27	static int gadc_thermal_adc_to_temp(struct gadc_thermal_info *gti, int val)
	28	{
	29	int temp, adc_hi, adc_lo;
	30	int i;
	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 - 1)) {
	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	temp = gti->lookup_table[2 * i];
	45	temp -= ((val - adc_lo) * 1000) / (adc_hi - adc_lo);
	46	}
	47
	48	return temp;
	49	}
	50
	51	static int gadc_thermal_get_temp(void data, int temp)
	52	{
	53	struct gadc_thermal_info *gti = data;
	54	int val;
	55	int ret;
	56
	57	ret = iio_read_channel_processed(gti->channel, &val);
	58	if (ret < 0) {
	59	dev_err(gti->dev, "IIO channel read failed %d\n", ret);
	60	return ret;
	61	}
	62	*temp = gadc_thermal_adc_to_temp(gti, val);
	63
	64	return 0;
65	}
66
67	static const struct thermal_zone_of_device_ops gadc_thermal_ops = {
68	.get_temp = gadc_thermal_get_temp,
69	};
70
71	static int gadc_thermal_read_linear_lookup_table(struct device *dev,
72	struct gadc_thermal_info *gti)
73	{
74	struct device_node *np = dev->of_node;
75	int ntable;
76	int ret;
77
78	ntable = of_property_count_elems_of_size(np, "temperature-lookup-table",
79	sizeof(u32));
80	if (ntable < 0) {
81	dev_err(dev, "Lookup table is not provided\n");
82	return ntable;
83	}
84
85	if (ntable % 2) {
86	dev_err(dev, "Pair of temperature vs ADC read value missing\n");
87	return -EINVAL;
88	}
89
a86854d0 KC	90	gti->lookup_table = devm_kcalloc(dev,
	91	ntable, sizeof(*gti->lookup_table),
	92	GFP_KERNEL);
b3aef78f LD	93	if (!gti->lookup_table)
	94	return -ENOMEM;
	95
	96	ret = of_property_read_u32_array(np, "temperature-lookup-table",
	97	(u32 *)gti->lookup_table, ntable);
	98	if (ret < 0) {
	99	dev_err(dev, "Failed to read temperature lookup table: %d\n",
	100	ret);
	101	return ret;
	102	}
	103
	104	gti->nlookup_table = ntable / 2;
	105
	106	return 0;
	107	}
	108
	109	static int gadc_thermal_probe(struct platform_device *pdev)
	110	{
	111	struct gadc_thermal_info *gti;
	112	int ret;
	113
	114	if (!pdev->dev.of_node) {
	115	dev_err(&pdev->dev, "Only DT based supported\n");
	116	return -ENODEV;
	117	}
	118
	119	gti = devm_kzalloc(&pdev->dev, sizeof(*gti), GFP_KERNEL);
	120	if (!gti)
	121	return -ENOMEM;
	122
	123	ret = gadc_thermal_read_linear_lookup_table(&pdev->dev, gti);
	124	if (ret < 0)
	125	return ret;
	126
	127	gti->dev = &pdev->dev;
	128	platform_set_drvdata(pdev, gti);
	129
d377aba1	130	gti->channel = devm_iio_channel_get(&pdev->dev, "sensor-channel");
b3aef78f LD	131	if (IS_ERR(gti->channel)) {
	132	ret = PTR_ERR(gti->channel);
	133	dev_err(&pdev->dev, "IIO channel not found: %d\n", ret);
	134	return ret;
	135	}
	136
d377aba1 DL	137	gti->tz_dev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, gti,
d377aba1 DL	138	&gadc_thermal_ops);
b3aef78f LD	139	if (IS_ERR(gti->tz_dev)) {
	140	ret = PTR_ERR(gti->tz_dev);
	141	dev_err(&pdev->dev, "Thermal zone sensor register failed: %d\n",
	142	ret);
d377aba1	143	return ret;
b3aef78f LD	144	}
b3aef78f LD	145
b3aef78f LD	146	return 0;
	147	}
	148
	149	static const struct of_device_id of_adc_thermal_match[] = {
	150	{ .compatible = "generic-adc-thermal", },
	151	{},
	152	};
	153	MODULE_DEVICE_TABLE(of, of_adc_thermal_match);
	154
	155	static struct platform_driver gadc_thermal_driver = {
	156	.driver = {
	157	.name = "generic-adc-thermal",
	158	.of_match_table = of_adc_thermal_match,
	159	},
	160	.probe = gadc_thermal_probe,
b3aef78f LD	161	};
	162
	163	module_platform_driver(gadc_thermal_driver);
	164
	165	MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
	166	MODULE_DESCRIPTION("Generic ADC thermal driver using IIO framework with DT");
	167	MODULE_LICENSE("GPL v2");