drivers/thermal/bcm2835-thermal.c

   1 /*****************************************************************************
   2 * Copyright 2011 Broadcom Corporation.  All rights reserved.
   3 *
   4 * Unless you and Broadcom execute a separate written software license
   5 * agreement governing use of this software, this software is licensed to you
   6 * under the terms of the GNU General Public License version 2, available at
   7 * http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
   8 *
   9 * Notwithstanding the above, under no circumstances may you combine this
  10 * software in any way with any other Broadcom software provided under a
  11 * license other than the GPL, without Broadcom's express prior written
  12 * consent.
  13 *****************************************************************************/
  14
  15 #include <linux/module.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/thermal.h>
  18 #include <soc/bcm2835/raspberrypi-firmware.h>
  19
  20 static int bcm2835_thermal_get_property(struct thermal_zone_device *tz,
  21                                         int *temp, u32 tag)
  22 {
  23         struct rpi_firmware *fw = tz->devdata;
  24         struct {
  25                 u32 id;
  26                 u32 val;
  27         } packet;
  28         int ret;
  29
  30         *temp = 0;
  31         packet.id = 0;
  32         ret = rpi_firmware_property(fw, tag, &packet, sizeof(packet));
  33         if (ret) {
  34                 dev_err(&tz->device, "Failed to get temperature\n");
  35                 return ret;
  36         }
  37
  38         *temp = packet.val;
  39         dev_dbg(&tz->device, "%stemp=%d\n",
  40                 tag == RPI_FIRMWARE_GET_MAX_TEMPERATURE ? "max" : "", *temp);
  41
  42         return 0;
  43 }
  44
  45 static int bcm2835_thermal_get_temp(struct thermal_zone_device *tz,
  46                                     int *temp)
  47 {
  48         return bcm2835_thermal_get_property(tz, temp,
  49                                             RPI_FIRMWARE_GET_TEMPERATURE);
  50 }
  51
  52 static struct thermal_zone_device_ops ops  = {
  53         .get_temp = bcm2835_thermal_get_temp,
  54 };
  55
  56 static int bcm2835_thermal_probe(struct platform_device *pdev)
  57 {
  58         struct device_node *fw_np;
  59         struct rpi_firmware *fw;
  60         struct thermal_zone_device *tz;
  61
  62         fw_np = of_parse_phandle(pdev->dev.of_node, "firmware", 0);
  63         if (!fw_np) {
  64                 dev_err(&pdev->dev, "Missing firmware node\n");
  65                 return -ENOENT;
  66         }
  67         fw = rpi_firmware_get(fw_np);
  68         if (!fw)
  69                 return -EPROBE_DEFER;
  70
  71         tz = thermal_zone_device_register("bcm2835_thermal", 0, 0, fw, &ops,
  72                                           NULL, 0, 0);
  73         if (IS_ERR(tz)) {
  74                 dev_err(&pdev->dev, "Failed to register the thermal device\n");
  75                 return PTR_ERR(tz);
  76         }
  77
  78         platform_set_drvdata(pdev, tz);
  79
  80         return 0;
  81 }
  82
  83 static int bcm2835_thermal_remove(struct platform_device *pdev)
  84 {
  85         thermal_zone_device_unregister(platform_get_drvdata(pdev));
  86
  87         return 0;
  88 }
  89
  90 static const struct of_device_id bcm2835_thermal_of_match_table[] = {
  91         { .compatible = "brcm,bcm2835-thermal", },
  92         {},
  93 };
  94 MODULE_DEVICE_TABLE(of, bcm2835_thermal_of_match_table);
  95
  96 static struct platform_driver bcm2835_thermal_driver = {
  97         .probe = bcm2835_thermal_probe,
  98         .remove = bcm2835_thermal_remove,
  99         .driver = {
 100                 .name = "bcm2835_thermal",
 101                 .of_match_table = bcm2835_thermal_of_match_table,
 102         },
 103 };
 104 module_platform_driver(bcm2835_thermal_driver);
 105
 106 MODULE_AUTHOR("Dorian Peake");
 107 MODULE_AUTHOR("Noralf Trønnes");
 108 MODULE_DESCRIPTION("Thermal driver for bcm2835 chip");
 109 MODULE_LICENSE("GPL");