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(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
  37 static struct thermal_zone_of_device_ops thermal_mmio_ops = {
  38         .get_temp = thermal_mmio_get_temperature,
  39 };
  40
  41 static 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                 dev_err(&pdev->dev, "failed to ioremap memory (%ld)\n",
  59                         PTR_ERR(sensor->mmio_base));
  60                 return PTR_ERR(sensor->mmio_base);
  61         }
  62
  63         sensor_init_func = device_get_match_data(&pdev->dev);
  64         if (sensor_init_func) {
  65                 ret = sensor_init_func(pdev, sensor);
  66                 if (ret) {
  67                         dev_err(&pdev->dev,
  68                                 "failed to initialize sensor (%d)\n",
  69                                 ret);
  70                         return ret;
  71                 }
  72         }
  73
  74         thermal_zone = devm_thermal_zone_of_sensor_register(&pdev->dev,
  75                                                             0,
  76                                                             sensor,
  77                                                             &thermal_mmio_ops);
  78         if (IS_ERR(thermal_zone)) {
  79                 dev_err(&pdev->dev,
  80                         "failed to register sensor (%ld)\n",
  81                         PTR_ERR(thermal_zone));
  82                 return PTR_ERR(thermal_zone);
  83         }
  84
  85         thermal_mmio_get_temperature(sensor, &temperature);
  86         dev_info(&pdev->dev,
  87                  "thermal mmio sensor %s registered, current temperature: %d\n",
  88                  pdev->name, temperature);
  89
  90         return 0;
  91 }
  92
  93 static int al_thermal_init(struct platform_device *pdev,
  94                            struct thermal_mmio *sensor)
  95 {
  96         sensor->read_mmio = thermal_mmio_readb;
  97         sensor->mask = 0xff;
  98         sensor->factor = 1000;
  99
 100         return 0;
 101 }
 102
 103 static const struct of_device_id thermal_mmio_id_table[] = {
 104         { .compatible = "amazon,al-thermal", .data = al_thermal_init},
 105         {}
 106 };
 107 MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
 108
 109 static struct platform_driver thermal_mmio_driver = {
 110         .probe = thermal_mmio_probe,
 111         .driver = {
 112                 .name = "thermal-mmio",
 113                 .owner = THIS_MODULE,
 114                 .of_match_table = of_match_ptr(thermal_mmio_id_table),
 115         },
 116 };
 117
 118 module_platform_driver(thermal_mmio_driver);
 119
 120 MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>");
 121 MODULE_DESCRIPTION("Thermal MMIO Driver");
 122 MODULE_LICENSE("GPL v2");