linux/drivers/thermal/dove_thermal.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Dove thermal sensor driver
   4 *
   5 * Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch>
   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 DOVE_THERMAL_TEMP_OFFSET        1
  17#define DOVE_THERMAL_TEMP_MASK          0x1FF
  18
  19/* Dove Thermal Manager Control and Status Register */
  20#define PMU_TM_DISABLE_OFFS             0
  21#define PMU_TM_DISABLE_MASK             (0x1 << PMU_TM_DISABLE_OFFS)
  22
  23/* Dove Theraml Diode Control 0 Register */
  24#define PMU_TDC0_SW_RST_MASK            (0x1 << 1)
  25#define PMU_TDC0_SEL_VCAL_OFFS          5
  26#define PMU_TDC0_SEL_VCAL_MASK          (0x3 << PMU_TDC0_SEL_VCAL_OFFS)
  27#define PMU_TDC0_REF_CAL_CNT_OFFS       11
  28#define PMU_TDC0_REF_CAL_CNT_MASK       (0x1FF << PMU_TDC0_REF_CAL_CNT_OFFS)
  29#define PMU_TDC0_AVG_NUM_OFFS           25
  30#define PMU_TDC0_AVG_NUM_MASK           (0x7 << PMU_TDC0_AVG_NUM_OFFS)
  31
  32/* Dove Thermal Diode Control 1 Register */
  33#define PMU_TEMP_DIOD_CTRL1_REG         0x04
  34#define PMU_TDC1_TEMP_VALID_MASK        (0x1 << 10)
  35
  36/* Dove Thermal Sensor Dev Structure */
  37struct dove_thermal_priv {
  38        void __iomem *sensor;
  39        void __iomem *control;
  40};
  41
  42static int dove_init_sensor(const struct dove_thermal_priv *priv)
  43{
  44        u32 reg;
  45        u32 i;
  46
  47        /* Configure the Diode Control Register #0 */
  48        reg = readl_relaxed(priv->control);
  49
  50        /* Use average of 2 */
  51        reg &= ~PMU_TDC0_AVG_NUM_MASK;
  52        reg |= (0x1 << PMU_TDC0_AVG_NUM_OFFS);
  53
  54        /* Reference calibration value */
  55        reg &= ~PMU_TDC0_REF_CAL_CNT_MASK;
  56        reg |= (0x0F1 << PMU_TDC0_REF_CAL_CNT_OFFS);
  57
  58        /* Set the high level reference for calibration */
  59        reg &= ~PMU_TDC0_SEL_VCAL_MASK;
  60        reg |= (0x2 << PMU_TDC0_SEL_VCAL_OFFS);
  61        writel(reg, priv->control);
  62
  63        /* Reset the sensor */
  64        reg = readl_relaxed(priv->control);
  65        writel((reg | PMU_TDC0_SW_RST_MASK), priv->control);
  66        writel(reg, priv->control);
  67
  68        /* Enable the sensor */
  69        reg = readl_relaxed(priv->sensor);
  70        reg &= ~PMU_TM_DISABLE_MASK;
  71        writel(reg, priv->sensor);
  72
  73        /* Poll the sensor for the first reading */
  74        for (i = 0; i < 1000000; i++) {
  75                reg = readl_relaxed(priv->sensor);
  76                if (reg & DOVE_THERMAL_TEMP_MASK)
  77                        break;
  78        }
  79
  80        if (i == 1000000)
  81                return -EIO;
  82
  83        return 0;
  84}
  85
  86static int dove_get_temp(struct thermal_zone_device *thermal,
  87                          int *temp)
  88{
  89        unsigned long reg;
  90        struct dove_thermal_priv *priv = thermal->devdata;
  91
  92        /* Valid check */
  93        reg = readl_relaxed(priv->control + PMU_TEMP_DIOD_CTRL1_REG);
  94        if ((reg & PMU_TDC1_TEMP_VALID_MASK) == 0x0) {
  95                dev_err(&thermal->device,
  96                        "Temperature sensor reading not valid\n");
  97                return -EIO;
  98        }
  99
 100        /*
 101         * Calculate temperature. According to Marvell internal
 102         * documentation the formula for this is:
 103         * Celsius = (322-reg)/1.3625
 104         */
 105        reg = readl_relaxed(priv->sensor);
 106        reg = (reg >> DOVE_THERMAL_TEMP_OFFSET) & DOVE_THERMAL_TEMP_MASK;
 107        *temp = ((3220000000UL - (10000000UL * reg)) / 13625);
 108
 109        return 0;
 110}
 111
 112static struct thermal_zone_device_ops ops = {
 113        .get_temp = dove_get_temp,
 114};
 115
 116static const struct of_device_id dove_thermal_id_table[] = {
 117        { .compatible = "marvell,dove-thermal" },
 118        {}
 119};
 120
 121static int dove_thermal_probe(struct platform_device *pdev)
 122{
 123        struct thermal_zone_device *thermal = NULL;
 124        struct dove_thermal_priv *priv;
 125        struct resource *res;
 126        int ret;
 127
 128        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 129        if (!priv)
 130                return -ENOMEM;
 131
 132        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 133        priv->sensor = devm_ioremap_resource(&pdev->dev, res);
 134        if (IS_ERR(priv->sensor))
 135                return PTR_ERR(priv->sensor);
 136
 137        res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 138        priv->control = devm_ioremap_resource(&pdev->dev, res);
 139        if (IS_ERR(priv->control))
 140                return PTR_ERR(priv->control);
 141
 142        ret = dove_init_sensor(priv);
 143        if (ret) {
 144                dev_err(&pdev->dev, "Failed to initialize sensor\n");
 145                return ret;
 146        }
 147
 148        thermal = thermal_zone_device_register("dove_thermal", 0, 0,
 149                                               priv, &ops, NULL, 0, 0);
 150        if (IS_ERR(thermal)) {
 151                dev_err(&pdev->dev,
 152                        "Failed to register thermal zone device\n");
 153                return PTR_ERR(thermal);
 154        }
 155
 156        platform_set_drvdata(pdev, thermal);
 157
 158        return 0;
 159}
 160
 161static int dove_thermal_exit(struct platform_device *pdev)
 162{
 163        struct thermal_zone_device *dove_thermal =
 164                platform_get_drvdata(pdev);
 165
 166        thermal_zone_device_unregister(dove_thermal);
 167
 168        return 0;
 169}
 170
 171MODULE_DEVICE_TABLE(of, dove_thermal_id_table);
 172
 173static struct platform_driver dove_thermal_driver = {
 174        .probe = dove_thermal_probe,
 175        .remove = dove_thermal_exit,
 176        .driver = {
 177                .name = "dove_thermal",
 178                .of_match_table = dove_thermal_id_table,
 179        },
 180};
 181
 182module_platform_driver(dove_thermal_driver);
 183
 184MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
 185MODULE_DESCRIPTION("Dove thermal driver");
 186MODULE_LICENSE("GPL");
 187