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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Generic ADC thermal driver
 *
 * Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
 *
 * Author: Laxman Dewangan <ldewangan@nvidia.com>
 */
#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, temp_hi, temp_lo, adc_hi, adc_lo;
	int i;

	if (!gti->lookup_table)
		return val;

	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) {
		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_hi = gti->lookup_table[2 * i - 2];
		temp_lo = gti->lookup_table[2 * i];

		temp = temp_hi + mult_frac(temp_lo - temp_hi, val - adc_hi,
					   adc_lo - adc_hi);
	}

	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;
	enum iio_chan_type chan_type;
	int ntable;
	int ret;

	ntable = of_property_count_elems_of_size(np, "temperature-lookup-table",
						 sizeof(u32));
	if (ntable <= 0) {
		ret = iio_get_channel_type(gti->channel, &chan_type);
		if (ret || chan_type != IIO_TEMP)
			dev_notice(dev,
				   "no lookup table, assuming DAC channel returns milliCelcius\n");
		return 0;
	}

	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;

	gti->channel = devm_iio_channel_get(&pdev->dev, "sensor-channel");
	if (IS_ERR(gti->channel)) {
		ret = PTR_ERR(gti->channel);
		if (ret != -EPROBE_DEFER)
			dev_err(&pdev->dev, "IIO channel not found: %d\n", ret);
		return ret;
	}

	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->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);
		if (ret != -EPROBE_DEFER)
			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
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
b3aef78f LD	2	/*
	3	* Generic ADC thermal driver
	4	*
	5	* Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
	6	*
	7	* Author: Laxman Dewangan <ldewangan@nvidia.com>
b3aef78f LD	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
	16	struct 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
	24	static int gadc_thermal_adc_to_temp(struct gadc_thermal_info *gti, int val)
	25	{
9d216211	26	int temp, temp_hi, temp_lo, adc_hi, adc_lo;
b3aef78f LD	27	int i;
b3aef78f LD	28
d36e2fa0 JFD	29	if (!gti->lookup_table)
	30	return val;
	31
b3aef78f LD	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];
9d216211	39	} else if (i >= gti->nlookup_table) {
b3aef78f LD	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];
9d216211 BA	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);
b3aef78f LD	50	}
	51
	52	return temp;
	53	}
	54
	55	static 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
	71	static const struct thermal_zone_of_device_ops gadc_thermal_ops = {
	72	.get_temp = gadc_thermal_get_temp,
	73	};
	74
	75	static 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;
07d243a6	79	enum iio_chan_type chan_type;
b3aef78f LD	80	int ntable;
	81	int ret;
	82
	83	ntable = of_property_count_elems_of_size(np, "temperature-lookup-table",
	84	sizeof(u32));
d36e2fa0	85	if (ntable <= 0) {
07d243a6 MB	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");
d36e2fa0	90	return 0;
b3aef78f LD	91	}
	92
	93	if (ntable % 2) {
	94	dev_err(dev, "Pair of temperature vs ADC read value missing\n");
	95	return -EINVAL;
	96	}
	97
a86854d0 KC	98	gti->lookup_table = devm_kcalloc(dev,
	99	ntable, sizeof(*gti->lookup_table),
	100	GFP_KERNEL);
b3aef78f LD	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
	117	static 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
d377aba1	131	gti->channel = devm_iio_channel_get(&pdev->dev, "sensor-channel");
b3aef78f LD	132	if (IS_ERR(gti->channel)) {
b3aef78f LD	133	ret = PTR_ERR(gti->channel);
86bd20a5 HYW	134	if (ret != -EPROBE_DEFER)
86bd20a5 HYW	135	dev_err(&pdev->dev, "IIO channel not found: %d\n", ret);
b3aef78f LD	136	return ret;
	137	}
	138
c1fde6e1 MB	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
d377aba1 DL	146	gti->tz_dev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, gti,
d377aba1 DL	147	&gadc_thermal_ops);
b3aef78f LD	148	if (IS_ERR(gti->tz_dev)) {
b3aef78f LD	149	ret = PTR_ERR(gti->tz_dev);
86bd20a5 HYW	150	if (ret != -EPROBE_DEFER)
	151	dev_err(&pdev->dev,
	152	"Thermal zone sensor register failed: %d\n",
	153	ret);
d377aba1	154	return ret;
b3aef78f LD	155	}
b3aef78f LD	156
b3aef78f LD	157	return 0;
	158	}
	159
	160	static const struct of_device_id of_adc_thermal_match[] = {
	161	{ .compatible = "generic-adc-thermal", },
	162	{},
	163	};
	164	MODULE_DEVICE_TABLE(of, of_adc_thermal_match);
	165
	166	static 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,
b3aef78f LD	172	};
	173
	174	module_platform_driver(gadc_thermal_driver);
	175
	176	MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
	177	MODULE_DESCRIPTION("Generic ADC thermal driver using IIO framework with DT");
	178	MODULE_LICENSE("GPL v2");