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