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/platform_device.h>
  19 #include <linux/of_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(void *data, int *temp)
  35 {
  36         struct bcm2711_thermal_priv *priv = data;
  37         int slope = thermal_zone_get_slope(priv->thermal);
  38         int offset = thermal_zone_get_offset(priv->thermal);
  39         u32 val;
  40         int ret;
  41         long t;
  42
  43         ret = regmap_read(priv->regmap, AVS_RO_TEMP_STATUS, &val);
  44         if (ret)
  45                 return ret;
  46
  47         if (!(val & AVS_RO_TEMP_STATUS_VALID_MSK))
  48                 return -EIO;
  49
  50         val &= AVS_RO_TEMP_STATUS_DATA_MSK;
  51
  52         /* Convert a HW code to a temperature reading (millidegree celsius) */
  53         t = slope * val + offset;
  54
  55         *temp = t < 0 ? 0 : t;
  56
  57         return 0;
  58 }
  59
  60 static const struct thermal_zone_of_device_ops bcm2711_thermal_of_ops = {
  61         .get_temp       = bcm2711_get_temp,
  62 };
  63
  64 static const struct of_device_id bcm2711_thermal_id_table[] = {
  65         { .compatible = "brcm,bcm2711-thermal" },
  66         {},
  67 };
  68 MODULE_DEVICE_TABLE(of, bcm2711_thermal_id_table);
  69
  70 static int bcm2711_thermal_probe(struct platform_device *pdev)
  71 {
  72         struct thermal_zone_device *thermal;
  73         struct bcm2711_thermal_priv *priv;
  74         struct device *dev = &pdev->dev;
  75         struct device_node *parent;
  76         struct regmap *regmap;
  77         int ret;
  78
  79         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  80         if (!priv)
  81                 return -ENOMEM;
  82
  83         /* get regmap from syscon node */
  84         parent = of_get_parent(dev->of_node); /* parent should be syscon node */
  85         regmap = syscon_node_to_regmap(parent);
  86         of_node_put(parent);
  87         if (IS_ERR(regmap)) {
  88                 ret = PTR_ERR(regmap);
  89                 dev_err(dev, "failed to get regmap: %d\n", ret);
  90                 return ret;
  91         }
  92         priv->regmap = regmap;
  93
  94         thermal = devm_thermal_zone_of_sensor_register(dev, 0, priv,
  95                                                        &bcm2711_thermal_of_ops);
  96         if (IS_ERR(thermal)) {
  97                 ret = PTR_ERR(thermal);
  98                 dev_err(dev, "could not register sensor: %d\n", ret);
  99                 return ret;
 100         }
 101
 102         priv->thermal = thermal;
 103
 104         thermal->tzp->no_hwmon = false;
 105         return thermal_add_hwmon_sysfs(thermal);
 106 }
 107
 108 static struct platform_driver bcm2711_thermal_driver = {
 109         .probe = bcm2711_thermal_probe,
 110         .driver = {
 111                 .name = "bcm2711_thermal",
 112                 .of_match_table = bcm2711_thermal_id_table,
 113         },
 114 };
 115 module_platform_driver(bcm2711_thermal_driver);
 116
 117 MODULE_LICENSE("GPL");
 118 MODULE_AUTHOR("Stefan Wahren");
 119 MODULE_DESCRIPTION("Broadcom AVS RO thermal sensor driver");