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(void *private, int *temp)
 24{
 25	int t;
 26	struct thermal_mmio *sensor =
 27		(struct thermal_mmio *)private;
 28
 29	t = sensor->read_mmio(sensor->mmio_base) & sensor->mask;
 30	t *= sensor->factor;
 31
 32	*temp = t;
 33
 34	return 0;
 35}
 36
 37static struct thermal_zone_of_device_ops thermal_mmio_ops = {
 38	.get_temp = thermal_mmio_get_temperature,
 39};
 40
 41static int thermal_mmio_probe(struct platform_device *pdev)
 42{
 43	struct resource *resource;
 44	struct thermal_mmio *sensor;
 45	int (*sensor_init_func)(struct platform_device *pdev,
 46				struct thermal_mmio *sensor);
 47	struct thermal_zone_device *thermal_zone;
 48	int ret;
 49	int temperature;
 50
 51	sensor = devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL);
 52	if (!sensor)
 53		return -ENOMEM;
 54
 55	resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 56	sensor->mmio_base = devm_ioremap_resource(&pdev->dev, resource);
 57	if (IS_ERR(sensor->mmio_base))
 58		return PTR_ERR(sensor->mmio_base);
 59
 60	sensor_init_func = device_get_match_data(&pdev->dev);
 61	if (sensor_init_func) {
 62		ret = sensor_init_func(pdev, sensor);
 63		if (ret) {
 64			dev_err(&pdev->dev,
 65				"failed to initialize sensor (%d)\n",
 66				ret);
 67			return ret;
 68		}
 69	}
 70
 71	thermal_zone = devm_thermal_zone_of_sensor_register(&pdev->dev,
 72							    0,
 73							    sensor,
 74							    &thermal_mmio_ops);
 75	if (IS_ERR(thermal_zone)) {
 76		dev_err(&pdev->dev,
 77			"failed to register sensor (%ld)\n",
 78			PTR_ERR(thermal_zone));
 79		return PTR_ERR(thermal_zone);
 80	}
 81
 82	thermal_mmio_get_temperature(sensor, &temperature);
 83	dev_info(&pdev->dev,
 84		 "thermal mmio sensor %s registered, current temperature: %d\n",
 85		 pdev->name, temperature);
 86
 87	return 0;
 88}
 89
 90static int al_thermal_init(struct platform_device *pdev,
 91			   struct thermal_mmio *sensor)
 92{
 93	sensor->read_mmio = thermal_mmio_readb;
 94	sensor->mask = 0xff;
 95	sensor->factor = 1000;
 96
 97	return 0;
 98}
 99
100static const struct of_device_id thermal_mmio_id_table[] = {
101	{ .compatible = "amazon,al-thermal", .data = al_thermal_init},
102	{}
103};
104MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
105
106static struct platform_driver thermal_mmio_driver = {
107	.probe = thermal_mmio_probe,
108	.driver = {
109		.name = "thermal-mmio",
110		.of_match_table = of_match_ptr(thermal_mmio_id_table),
111	},
112};
113
114module_platform_driver(thermal_mmio_driver);
115
116MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>");
117MODULE_DESCRIPTION("Thermal MMIO Driver");
118MODULE_LICENSE("GPL v2");