1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
  4 */
  5
  6#include <linux/module.h>
  7#include <linux/of_address.h>
  8#include <linux/platform_device.h>
  9#include <linux/thermal.h>
 10
 11struct thermal_mmio {
 12	void __iomem *mmio_base;
 13	u32 (*read_mmio)(void __iomem *mmio_base);
 14	u32 mask;
 15	int factor;
 16};
 17
 18static u32 thermal_mmio_readb(void __iomem *mmio_base)
 19{
 20	return readb(mmio_base);
 21}
 22
 23static int thermal_mmio_get_temperature(struct thermal_zone_device *tz, int *temp)
 24{
 25	int t;
 26	struct thermal_mmio *sensor = thermal_zone_device_priv(tz);
 27
 28	t = sensor->read_mmio(sensor->mmio_base) & sensor->mask;
 29	t *= sensor->factor;
 30
 31	*temp = t;
 32
 33	return 0;
 34}
 35
 36static const struct thermal_zone_device_ops thermal_mmio_ops = {
 37	.get_temp = thermal_mmio_get_temperature,
 38};
 39
 40static int thermal_mmio_probe(struct platform_device *pdev)
 41{
 42	struct thermal_mmio *sensor;
 43	int (*sensor_init_func)(struct platform_device *pdev,
 44				struct thermal_mmio *sensor);
 45	struct thermal_zone_device *thermal_zone;
 46	int ret;
 47	int temperature;
 48
 49	sensor = devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL);
 50	if (!sensor)
 51		return -ENOMEM;
 52
 53	sensor->mmio_base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
 54	if (IS_ERR(sensor->mmio_base))
 55		return PTR_ERR(sensor->mmio_base);
 56
 57	sensor_init_func = device_get_match_data(&pdev->dev);
 58	if (sensor_init_func) {
 59		ret = sensor_init_func(pdev, sensor);
 60		if (ret) {
 61			dev_err(&pdev->dev,
 62				"failed to initialize sensor (%d)\n",
 63				ret);
 64			return ret;
 65		}
 66	}
 67
 68	thermal_zone = devm_thermal_of_zone_register(&pdev->dev,
 69						     0,
 70						     sensor,
 71						     &thermal_mmio_ops);
 72	if (IS_ERR(thermal_zone)) {
 73		dev_err(&pdev->dev,
 74			"failed to register sensor (%ld)\n",
 75			PTR_ERR(thermal_zone));
 76		return PTR_ERR(thermal_zone);
 77	}
 78
 79	thermal_mmio_get_temperature(thermal_zone, &temperature);
 80	dev_info(&pdev->dev,
 81		 "thermal mmio sensor %s registered, current temperature: %d\n",
 82		 pdev->name, temperature);
 83
 84	return 0;
 85}
 86
 87static int al_thermal_init(struct platform_device *pdev,
 88			   struct thermal_mmio *sensor)
 89{
 90	sensor->read_mmio = thermal_mmio_readb;
 91	sensor->mask = 0xff;
 92	sensor->factor = 1000;
 93
 94	return 0;
 95}
 96
 97static const struct of_device_id thermal_mmio_id_table[] = {
 98	{ .compatible = "amazon,al-thermal", .data = al_thermal_init},
 99	{}
100};
101MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
102
103static struct platform_driver thermal_mmio_driver = {
104	.probe = thermal_mmio_probe,
105	.driver = {
106		.name = "thermal-mmio",
107		.of_match_table = thermal_mmio_id_table,
108	},
109};
110
111module_platform_driver(thermal_mmio_driver);
112
113MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>");
114MODULE_DESCRIPTION("Thermal MMIO Driver");
115MODULE_LICENSE("GPL v2");