drivers/thermal/thermal_mmio.c

   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
  11 struct thermal_mmio {
  12         void __iomem *mmio_base;
  13         u32 (*read_mmio)(void __iomem *mmio_base);
  14         u32 mask;
  15         int factor;
  16 };
  17
  18 static u32 thermal_mmio_readb(void __iomem *mmio_base)
  19 {
  20         return readb(mmio_base);
  21 }
  22
  23 static 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
  36 static const struct thermal_zone_device_ops thermal_mmio_ops = {
  37         .get_temp = thermal_mmio_get_temperature,
  38 };
  39
  40 static 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
  87 static 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
  97 static const struct of_device_id thermal_mmio_id_table[] = {
  98         { .compatible = "amazon,al-thermal", .data = al_thermal_init},
  99         {}
 100 };
 101 MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
 102
 103 static 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
 111 module_platform_driver(thermal_mmio_driver);
 112
 113 MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>");
 114 MODULE_DESCRIPTION("Thermal MMIO Driver");
 115 MODULE_LICENSE("GPL v2");