drivers/thermal/broadcom/bcm2711_thermal.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Broadcom AVS RO thermal sensor driver
   4  *
   5  * based on brcmstb_thermal
   6  *
   7  * Copyright (C) 2020 Stefan Wahren
   8  */
   9
  10 #include <linux/bitops.h>
  11 #include <linux/clk.h>
  12 #include <linux/device.h>
  13 #include <linux/err.h>
  14 #include <linux/io.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mfd/syscon.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/regmap.h>
  21 #include <linux/thermal.h>
  22
  23 #include "../thermal_hwmon.h"
  24
  25 #define AVS_RO_TEMP_STATUS              0x200
  26 #define AVS_RO_TEMP_STATUS_VALID_MSK    (BIT(16) | BIT(10))
  27 #define AVS_RO_TEMP_STATUS_DATA_MSK     GENMASK(9, 0)
  28
  29 struct bcm2711_thermal_priv {
  30         struct regmap *regmap;
  31         struct thermal_zone_device *thermal;
  32 };
  33
  34 static int bcm2711_get_temp(struct thermal_zone_device *tz, int *temp)
  35 {
  36         struct bcm2711_thermal_priv *priv = thermal_zone_device_priv(tz);
  37         int slope = thermal_zone_get_slope(tz);
  38         int offset = thermal_zone_get_offset(tz);
  39         u32 val;
  40         int ret;
  41
  42         ret = regmap_read(priv->regmap, AVS_RO_TEMP_STATUS, &val);
  43         if (ret)
  44                 return ret;
  45
  46         if (!(val & AVS_RO_TEMP_STATUS_VALID_MSK))
  47                 return -EIO;
  48
  49         val &= AVS_RO_TEMP_STATUS_DATA_MSK;
  50
  51         /* Convert a HW code to a temperature reading (millidegree celsius) */
  52         *temp = slope * val + offset;
  53
  54         return 0;
  55 }
  56
  57 static const struct thermal_zone_device_ops bcm2711_thermal_of_ops = {
  58         .get_temp       = bcm2711_get_temp,
  59 };
  60
  61 static const struct of_device_id bcm2711_thermal_id_table[] = {
  62         { .compatible = "brcm,bcm2711-thermal" },
  63         {},
  64 };
  65 MODULE_DEVICE_TABLE(of, bcm2711_thermal_id_table);
  66
  67 static int bcm2711_thermal_probe(struct platform_device *pdev)
  68 {
  69         struct thermal_zone_device *thermal;
  70         struct bcm2711_thermal_priv *priv;
  71         struct device *dev = &pdev->dev;
  72         struct device_node *parent;
  73         struct regmap *regmap;
  74         int ret;
  75
  76         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  77         if (!priv)
  78                 return -ENOMEM;
  79
  80         /* get regmap from syscon node */
  81         parent = of_get_parent(dev->of_node); /* parent should be syscon node */
  82         regmap = syscon_node_to_regmap(parent);
  83         of_node_put(parent);
  84         if (IS_ERR(regmap)) {
  85                 ret = PTR_ERR(regmap);
  86                 dev_err(dev, "failed to get regmap: %d\n", ret);
  87                 return ret;
  88         }
  89         priv->regmap = regmap;
  90
  91         thermal = devm_thermal_of_zone_register(dev, 0, priv,
  92                                                 &bcm2711_thermal_of_ops);
  93         if (IS_ERR(thermal)) {
  94                 ret = PTR_ERR(thermal);
  95                 dev_err(dev, "could not register sensor: %d\n", ret);
  96                 return ret;
  97         }
  98
  99         priv->thermal = thermal;
 100
 101         return thermal_add_hwmon_sysfs(thermal);
 102 }
 103
 104 static struct platform_driver bcm2711_thermal_driver = {
 105         .probe = bcm2711_thermal_probe,
 106         .driver = {
 107                 .name = "bcm2711_thermal",
 108                 .of_match_table = bcm2711_thermal_id_table,
 109         },
 110 };
 111 module_platform_driver(bcm2711_thermal_driver);
 112
 113 MODULE_LICENSE("GPL");
 114 MODULE_AUTHOR("Stefan Wahren");
 115 MODULE_DESCRIPTION("Broadcom AVS RO thermal sensor driver");