[linux-2.6-block.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;
	int ntable;
	int ret;

	ntable = of_property_count_elems_of_size(np, "temperature-lookup-table",
						 sizeof(u32));
	if (ntable <= 0) {
		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;

	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
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;
	79	int ntable;
	80	int ret;
	81
	82	ntable = of_property_count_elems_of_size(np, "temperature-lookup-table",
	83	sizeof(u32));
d36e2fa0 JFD	84	if (ntable <= 0) {
	85	dev_notice(dev, "no lookup table, assuming DAC channel returns milliCelcius\n");
	86	return 0;
b3aef78f LD	87	}
	88
	89	if (ntable % 2) {
	90	dev_err(dev, "Pair of temperature vs ADC read value missing\n");
	91	return -EINVAL;
	92	}
	93
a86854d0 KC	94	gti->lookup_table = devm_kcalloc(dev,
	95	ntable, sizeof(*gti->lookup_table),
	96	GFP_KERNEL);
b3aef78f LD	97	if (!gti->lookup_table)
	98	return -ENOMEM;
	99
	100	ret = of_property_read_u32_array(np, "temperature-lookup-table",
	101	(u32 *)gti->lookup_table, ntable);
	102	if (ret < 0) {
	103	dev_err(dev, "Failed to read temperature lookup table: %d\n",
	104	ret);
	105	return ret;
	106	}
	107
	108	gti->nlookup_table = ntable / 2;
	109
	110	return 0;
	111	}
	112
	113	static int gadc_thermal_probe(struct platform_device *pdev)
	114	{
	115	struct gadc_thermal_info *gti;
	116	int ret;
	117
	118	if (!pdev->dev.of_node) {
	119	dev_err(&pdev->dev, "Only DT based supported\n");
	120	return -ENODEV;
	121	}
	122
	123	gti = devm_kzalloc(&pdev->dev, sizeof(*gti), GFP_KERNEL);
	124	if (!gti)
	125	return -ENOMEM;
	126
	127	ret = gadc_thermal_read_linear_lookup_table(&pdev->dev, gti);
	128	if (ret < 0)
	129	return ret;
	130
	131	gti->dev = &pdev->dev;
	132	platform_set_drvdata(pdev, gti);
	133
d377aba1	134	gti->channel = devm_iio_channel_get(&pdev->dev, "sensor-channel");
b3aef78f LD	135	if (IS_ERR(gti->channel)) {
	136	ret = PTR_ERR(gti->channel);
	137	dev_err(&pdev->dev, "IIO channel not found: %d\n", ret);
	138	return ret;
	139	}
	140
d377aba1 DL	141	gti->tz_dev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, gti,
d377aba1 DL	142	&gadc_thermal_ops);
b3aef78f LD	143	if (IS_ERR(gti->tz_dev)) {
	144	ret = PTR_ERR(gti->tz_dev);
	145	dev_err(&pdev->dev, "Thermal zone sensor register failed: %d\n",
	146	ret);
d377aba1	147	return ret;
b3aef78f LD	148	}
b3aef78f LD	149
b3aef78f LD	150	return 0;
	151	}
	152
	153	static const struct of_device_id of_adc_thermal_match[] = {
	154	{ .compatible = "generic-adc-thermal", },
	155	{},
	156	};
	157	MODULE_DEVICE_TABLE(of, of_adc_thermal_match);
	158
	159	static struct platform_driver gadc_thermal_driver = {
	160	.driver = {
	161	.name = "generic-adc-thermal",
	162	.of_match_table = of_adc_thermal_match,
	163	},
	164	.probe = gadc_thermal_probe,
b3aef78f LD	165	};
	166
	167	module_platform_driver(gadc_thermal_driver);
	168
	169	MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
	170	MODULE_DESCRIPTION("Generic ADC thermal driver using IIO framework with DT");
	171	MODULE_LICENSE("GPL v2");