1 // SPDX-License-Identifier: GPL-2.0-only
3  * Generic ADC thermal driver
14 #include <linux/thermal.h>
31 	if (!gti->lookup_table)  in gadc_thermal_adc_to_temp()
34 	for (i = 0; i < gti->nlookup_table; i++) {  in gadc_thermal_adc_to_temp()
35 		if (val >= gti->lookup_table[2 * i + 1])  in gadc_thermal_adc_to_temp()
40 		temp = gti->lookup_table[0];  in gadc_thermal_adc_to_temp()
41 	} else if (i >= gti->nlookup_table) {  in gadc_thermal_adc_to_temp()
42 		temp = gti->lookup_table[2 * (gti->nlookup_table - 1)];  in gadc_thermal_adc_to_temp()
44 		adc_hi = gti->lookup_table[2 * i - 1];  in gadc_thermal_adc_to_temp()
45 		adc_lo = gti->lookup_table[2 * i + 1];  in gadc_thermal_adc_to_temp()
47 		temp_hi = gti->lookup_table[2 * i - 2];  in gadc_thermal_adc_to_temp()
48 		temp_lo = gti->lookup_table[2 * i];  in gadc_thermal_adc_to_temp()
50 		temp = temp_hi + mult_frac(temp_lo - temp_hi, val - adc_hi,  in gadc_thermal_adc_to_temp()
51 					   adc_lo - adc_hi);  in gadc_thermal_adc_to_temp()
63 	ret = iio_read_channel_processed(gti->channel, &val);  in gadc_thermal_get_temp()
79 	struct device_node *np = dev->of_node;  in gadc_thermal_read_linear_lookup_table()
84 	ntable = of_property_count_elems_of_size(np, "temperature-lookup-table",  in gadc_thermal_read_linear_lookup_table()
87 		ret = iio_get_channel_type(gti->channel, &chan_type);  in gadc_thermal_read_linear_lookup_table()
95 		dev_err(dev, "Pair of temperature vs ADC read value missing\n");  in gadc_thermal_read_linear_lookup_table()
96 		return -EINVAL;  in gadc_thermal_read_linear_lookup_table()
99 	gti->lookup_table = devm_kcalloc(dev,  in gadc_thermal_read_linear_lookup_table()
100 					 ntable, sizeof(*gti->lookup_table),  in gadc_thermal_read_linear_lookup_table()
102 	if (!gti->lookup_table)  in gadc_thermal_read_linear_lookup_table()
103 		return -ENOMEM;  in gadc_thermal_read_linear_lookup_table()
105 	ret = of_property_read_u32_array(np, "temperature-lookup-table",  in gadc_thermal_read_linear_lookup_table()
106 					 (u32 *)gti->lookup_table, ntable);  in gadc_thermal_read_linear_lookup_table()
113 	gti->nlookup_table = ntable / 2;  in gadc_thermal_read_linear_lookup_table()
123 	if (!pdev->dev.of_node) {  in gadc_thermal_probe()
124 		dev_err(&pdev->dev, "Only DT based supported\n");  in gadc_thermal_probe()
125 		return -ENODEV;  in gadc_thermal_probe()
128 	gti = devm_kzalloc(&pdev->dev, sizeof(*gti), GFP_KERNEL);  in gadc_thermal_probe()
130 		return -ENOMEM;  in gadc_thermal_probe()
132 	gti->channel = devm_iio_channel_get(&pdev->dev, "sensor-channel");  in gadc_thermal_probe()
133 	if (IS_ERR(gti->channel)) {  in gadc_thermal_probe()
134 		ret = PTR_ERR(gti->channel);  in gadc_thermal_probe()
135 		if (ret != -EPROBE_DEFER)  in gadc_thermal_probe()
136 			dev_err(&pdev->dev, "IIO channel not found: %d\n", ret);  in gadc_thermal_probe()
140 	ret = gadc_thermal_read_linear_lookup_table(&pdev->dev, gti);  in gadc_thermal_probe()
144 	gti->dev = &pdev->dev;  in gadc_thermal_probe()
146 	gti->tz_dev = devm_thermal_of_zone_register(&pdev->dev, 0, gti,  in gadc_thermal_probe()
148 	if (IS_ERR(gti->tz_dev)) {  in gadc_thermal_probe()
149 		ret = PTR_ERR(gti->tz_dev);  in gadc_thermal_probe()
150 		if (ret != -EPROBE_DEFER)  in gadc_thermal_probe()
151 			dev_err(&pdev->dev,  in gadc_thermal_probe()
152 				"Thermal zone sensor register failed: %d\n",  in gadc_thermal_probe()
157 	devm_thermal_add_hwmon_sysfs(&pdev->dev, gti->tz_dev);  in gadc_thermal_probe()
163 	{ .compatible = "generic-adc-thermal", },
170 		.name = "generic-adc-thermal",
179 MODULE_DESCRIPTION("Generic ADC thermal driver using IIO framework with DT");