drivers/thermal/broadcom/ns-thermal.c

   1 /*
   2  * Copyright (C) 2017 Rafał Miłecki <rafal@milecki.pl>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/of_address.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/thermal.h>
  13
  14 #define PVTMON_CONTROL0                                 0x00
  15 #define PVTMON_CONTROL0_SEL_MASK                        0x0000000e
  16 #define PVTMON_CONTROL0_SEL_TEMP_MONITOR                0x00000000
  17 #define PVTMON_CONTROL0_SEL_TEST_MODE                   0x0000000e
  18 #define PVTMON_STATUS                                   0x08
  19
  20 struct ns_thermal {
  21         struct thermal_zone_device *tz;
  22         void __iomem *pvtmon;
  23 };
  24
  25 static int ns_thermal_get_temp(void *data, int *temp)
  26 {
  27         struct ns_thermal *ns_thermal = data;
  28         int offset = thermal_zone_get_offset(ns_thermal->tz);
  29         int slope = thermal_zone_get_slope(ns_thermal->tz);
  30         u32 val;
  31
  32         val = readl(ns_thermal->pvtmon + PVTMON_CONTROL0);
  33         if ((val & PVTMON_CONTROL0_SEL_MASK) != PVTMON_CONTROL0_SEL_TEMP_MONITOR) {
  34                 /* Clear current mode selection */
  35                 val &= ~PVTMON_CONTROL0_SEL_MASK;
  36
  37                 /* Set temp monitor mode (it's the default actually) */
  38                 val |= PVTMON_CONTROL0_SEL_TEMP_MONITOR;
  39
  40                 writel(val, ns_thermal->pvtmon + PVTMON_CONTROL0);
  41         }
  42
  43         val = readl(ns_thermal->pvtmon + PVTMON_STATUS);
  44         *temp = slope * val + offset;
  45
  46         return 0;
  47 }
  48
  49 static const struct thermal_zone_of_device_ops ns_thermal_ops = {
  50         .get_temp = ns_thermal_get_temp,
  51 };
  52
  53 static int ns_thermal_probe(struct platform_device *pdev)
  54 {
  55         struct device *dev = &pdev->dev;
  56         struct ns_thermal *ns_thermal;
  57
  58         ns_thermal = devm_kzalloc(dev, sizeof(*ns_thermal), GFP_KERNEL);
  59         if (!ns_thermal)
  60                 return -ENOMEM;
  61
  62         ns_thermal->pvtmon = of_iomap(dev_of_node(dev), 0);
  63         if (WARN_ON(!ns_thermal->pvtmon))
  64                 return -ENOENT;
  65
  66         ns_thermal->tz = devm_thermal_zone_of_sensor_register(dev, 0,
  67                                                               ns_thermal,
  68                                                               &ns_thermal_ops);
  69         if (IS_ERR(ns_thermal->tz)) {
  70                 iounmap(ns_thermal->pvtmon);
  71                 return PTR_ERR(ns_thermal->tz);
  72         }
  73
  74         platform_set_drvdata(pdev, ns_thermal);
  75
  76         return 0;
  77 }
  78
  79 static int ns_thermal_remove(struct platform_device *pdev)
  80 {
  81         struct ns_thermal *ns_thermal = platform_get_drvdata(pdev);
  82
  83         iounmap(ns_thermal->pvtmon);
  84
  85         return 0;
  86 }
  87
  88 static const struct of_device_id ns_thermal_of_match[] = {
  89         { .compatible = "brcm,ns-thermal", },
  90         {},
  91 };
  92 MODULE_DEVICE_TABLE(of, ns_thermal_of_match);
  93
  94 static struct platform_driver ns_thermal_driver = {
  95         .probe          = ns_thermal_probe,
  96         .remove         = ns_thermal_remove,
  97         .driver = {
  98                 .name = "ns-thermal",
  99                 .of_match_table = ns_thermal_of_match,
 100         },
 101 };
 102 module_platform_driver(ns_thermal_driver);
 103
 104 MODULE_AUTHOR("Rafał Miłecki <rafal@milecki.pl>");
 105 MODULE_DESCRIPTION("Northstar thermal driver");
 106 MODULE_LICENSE("GPL v2");