LXR linux/drivers/thermal/kirkwood

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Kirkwood thermal sensor driver
   4 *
   5 * Copyright (C) 2012 Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
   6 */
   7#include <linux/device.h>
   8#include <linux/err.h>
   9#include <linux/io.h>
  10#include <linux/kernel.h>
  11#include <linux/of.h>
  12#include <linux/module.h>
  13#include <linux/platform_device.h>
  14#include <linux/thermal.h>
  15
  16#define KIRKWOOD_THERMAL_VALID_OFFSET   9
  17#define KIRKWOOD_THERMAL_VALID_MASK     0x1
  18#define KIRKWOOD_THERMAL_TEMP_OFFSET    10
  19#define KIRKWOOD_THERMAL_TEMP_MASK      0x1FF
  20
  21/* Kirkwood Thermal Sensor Dev Structure */
  22struct kirkwood_thermal_priv {
  23        void __iomem *sensor;
  24};
  25
  26static int kirkwood_get_temp(struct thermal_zone_device *thermal,
  27                          int *temp)
  28{
  29        unsigned long reg;
  30        struct kirkwood_thermal_priv *priv = thermal->devdata;
  31
  32        reg = readl_relaxed(priv->sensor);
  33
  34        /* Valid check */
  35        if (!((reg >> KIRKWOOD_THERMAL_VALID_OFFSET) &
  36            KIRKWOOD_THERMAL_VALID_MASK)) {
  37                dev_err(&thermal->device,
  38                        "Temperature sensor reading not valid\n");
  39                return -EIO;
  40        }
  41
  42        /*
  43         * Calculate temperature. According to Marvell internal
  44         * documentation the formula for this is:
  45         * Celsius = (322-reg)/1.3625
  46         */
  47        reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) &
  48                KIRKWOOD_THERMAL_TEMP_MASK;
  49        *temp = ((3220000000UL - (10000000UL * reg)) / 13625);
  50
  51        return 0;
  52}
  53
  54static struct thermal_zone_device_ops ops = {
  55        .get_temp = kirkwood_get_temp,
  56};
  57
  58static const struct of_device_id kirkwood_thermal_id_table[] = {
  59        { .compatible = "marvell,kirkwood-thermal" },
  60        {}
  61};
  62
  63static int kirkwood_thermal_probe(struct platform_device *pdev)
  64{
  65        struct thermal_zone_device *thermal = NULL;
  66        struct kirkwood_thermal_priv *priv;
  67        struct resource *res;
  68        int ret;
  69
  70        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  71        if (!priv)
  72                return -ENOMEM;
  73
  74        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  75        priv->sensor = devm_ioremap_resource(&pdev->dev, res);
  76        if (IS_ERR(priv->sensor))
  77                return PTR_ERR(priv->sensor);
  78
  79        thermal = thermal_zone_device_register("kirkwood_thermal", 0, 0,
  80                                               priv, &ops, NULL, 0, 0);
  81        if (IS_ERR(thermal)) {
  82                dev_err(&pdev->dev,
  83                        "Failed to register thermal zone device\n");
  84                return PTR_ERR(thermal);
  85        }
  86        ret = thermal_zone_device_enable(thermal);
  87        if (ret) {
  88                thermal_zone_device_unregister(thermal);
  89                dev_err(&pdev->dev, "Failed to enable thermal zone device\n");
  90                return ret;
  91        }
  92
  93        platform_set_drvdata(pdev, thermal);
  94
  95        return 0;
  96}
  97
  98static int kirkwood_thermal_exit(struct platform_device *pdev)
  99{
 100        struct thermal_zone_device *kirkwood_thermal =
 101                platform_get_drvdata(pdev);
 102
 103        thermal_zone_device_unregister(kirkwood_thermal);
 104
 105        return 0;
 106}
 107
 108MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table);
 109
 110static struct platform_driver kirkwood_thermal_driver = {
 111        .probe = kirkwood_thermal_probe,
 112        .remove = kirkwood_thermal_exit,
 113        .driver = {
 114                .name = "kirkwood_thermal",
 115                .of_match_table = kirkwood_thermal_id_table,
 116        },
 117};
 118
 119module_platform_driver(kirkwood_thermal_driver);
 120
 121MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>");
 122MODULE_DESCRIPTION("kirkwood thermal driver");
 123MODULE_LICENSE("GPL");
 124