linux/drivers/thermal/dove_thermal.c
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   1/*
   2 * Dove thermal sensor driver
   3 *
   4 * Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch>
   5 *
   6 * This software is licensed under the terms of the GNU General Public
   7 * License version 2, as published by the Free Software Foundation, and
   8 * may be copied, distributed, and modified under those terms.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13 * GNU General Public License for more details.
  14 *
  15 */
  16#include <linux/device.h>
  17#include <linux/err.h>
  18#include <linux/io.h>
  19#include <linux/kernel.h>
  20#include <linux/of.h>
  21#include <linux/module.h>
  22#include <linux/platform_device.h>
  23#include <linux/thermal.h>
  24
  25#define DOVE_THERMAL_TEMP_OFFSET        1
  26#define DOVE_THERMAL_TEMP_MASK          0x1FF
  27
  28/* Dove Thermal Manager Control and Status Register */
  29#define PMU_TM_DISABLE_OFFS             0
  30#define PMU_TM_DISABLE_MASK             (0x1 << PMU_TM_DISABLE_OFFS)
  31
  32/* Dove Theraml Diode Control 0 Register */
  33#define PMU_TDC0_SW_RST_MASK            (0x1 << 1)
  34#define PMU_TDC0_SEL_VCAL_OFFS          5
  35#define PMU_TDC0_SEL_VCAL_MASK          (0x3 << PMU_TDC0_SEL_VCAL_OFFS)
  36#define PMU_TDC0_REF_CAL_CNT_OFFS       11
  37#define PMU_TDC0_REF_CAL_CNT_MASK       (0x1FF << PMU_TDC0_REF_CAL_CNT_OFFS)
  38#define PMU_TDC0_AVG_NUM_OFFS           25
  39#define PMU_TDC0_AVG_NUM_MASK           (0x7 << PMU_TDC0_AVG_NUM_OFFS)
  40
  41/* Dove Thermal Diode Control 1 Register */
  42#define PMU_TEMP_DIOD_CTRL1_REG         0x04
  43#define PMU_TDC1_TEMP_VALID_MASK        (0x1 << 10)
  44
  45/* Dove Thermal Sensor Dev Structure */
  46struct dove_thermal_priv {
  47        void __iomem *sensor;
  48        void __iomem *control;
  49};
  50
  51static int dove_init_sensor(const struct dove_thermal_priv *priv)
  52{
  53        u32 reg;
  54        u32 i;
  55
  56        /* Configure the Diode Control Register #0 */
  57        reg = readl_relaxed(priv->control);
  58
  59        /* Use average of 2 */
  60        reg &= ~PMU_TDC0_AVG_NUM_MASK;
  61        reg |= (0x1 << PMU_TDC0_AVG_NUM_OFFS);
  62
  63        /* Reference calibration value */
  64        reg &= ~PMU_TDC0_REF_CAL_CNT_MASK;
  65        reg |= (0x0F1 << PMU_TDC0_REF_CAL_CNT_OFFS);
  66
  67        /* Set the high level reference for calibration */
  68        reg &= ~PMU_TDC0_SEL_VCAL_MASK;
  69        reg |= (0x2 << PMU_TDC0_SEL_VCAL_OFFS);
  70        writel(reg, priv->control);
  71
  72        /* Reset the sensor */
  73        reg = readl_relaxed(priv->control);
  74        writel((reg | PMU_TDC0_SW_RST_MASK), priv->control);
  75        writel(reg, priv->control);
  76
  77        /* Enable the sensor */
  78        reg = readl_relaxed(priv->sensor);
  79        reg &= ~PMU_TM_DISABLE_MASK;
  80        writel(reg, priv->sensor);
  81
  82        /* Poll the sensor for the first reading */
  83        for (i = 0; i < 1000000; i++) {
  84                reg = readl_relaxed(priv->sensor);
  85                if (reg & DOVE_THERMAL_TEMP_MASK)
  86                        break;
  87        }
  88
  89        if (i == 1000000)
  90                return -EIO;
  91
  92        return 0;
  93}
  94
  95static int dove_get_temp(struct thermal_zone_device *thermal,
  96                          unsigned long *temp)
  97{
  98        unsigned long reg;
  99        struct dove_thermal_priv *priv = thermal->devdata;
 100
 101        /* Valid check */
 102        reg = readl_relaxed(priv->control + PMU_TEMP_DIOD_CTRL1_REG);
 103        if ((reg & PMU_TDC1_TEMP_VALID_MASK) == 0x0) {
 104                dev_err(&thermal->device,
 105                        "Temperature sensor reading not valid\n");
 106                return -EIO;
 107        }
 108
 109        /*
 110         * Calculate temperature. See Section 8.10.1 of 88AP510,
 111         * Documentation/arm/Marvell/README
 112         */
 113        reg = readl_relaxed(priv->sensor);
 114        reg = (reg >> DOVE_THERMAL_TEMP_OFFSET) & DOVE_THERMAL_TEMP_MASK;
 115        *temp = ((2281638UL - (7298*reg)) / 10);
 116
 117        return 0;
 118}
 119
 120static struct thermal_zone_device_ops ops = {
 121        .get_temp = dove_get_temp,
 122};
 123
 124static const struct of_device_id dove_thermal_id_table[] = {
 125        { .compatible = "marvell,dove-thermal" },
 126        {}
 127};
 128
 129static int dove_thermal_probe(struct platform_device *pdev)
 130{
 131        struct thermal_zone_device *thermal = NULL;
 132        struct dove_thermal_priv *priv;
 133        struct resource *res;
 134        int ret;
 135
 136        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 137        if (!res) {
 138                dev_err(&pdev->dev, "Failed to get platform resource\n");
 139                return -ENODEV;
 140        }
 141
 142        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 143        if (!priv)
 144                return -ENOMEM;
 145
 146        priv->sensor = devm_ioremap_resource(&pdev->dev, res);
 147        if (IS_ERR(priv->sensor))
 148                return PTR_ERR(priv->sensor);
 149
 150        res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 151        if (!res) {
 152                dev_err(&pdev->dev, "Failed to get platform resource\n");
 153                return -ENODEV;
 154        }
 155        priv->control = devm_ioremap_resource(&pdev->dev, res);
 156        if (IS_ERR(priv->control))
 157                return PTR_ERR(priv->control);
 158
 159        ret = dove_init_sensor(priv);
 160        if (ret) {
 161                dev_err(&pdev->dev, "Failed to initialize sensor\n");
 162                return ret;
 163        }
 164
 165        thermal = thermal_zone_device_register("dove_thermal", 0, 0,
 166                                               priv, &ops, NULL, 0, 0);
 167        if (IS_ERR(thermal)) {
 168                dev_err(&pdev->dev,
 169                        "Failed to register thermal zone device\n");
 170                return PTR_ERR(thermal);
 171        }
 172
 173        platform_set_drvdata(pdev, thermal);
 174
 175        return 0;
 176}
 177
 178static int dove_thermal_exit(struct platform_device *pdev)
 179{
 180        struct thermal_zone_device *dove_thermal =
 181                platform_get_drvdata(pdev);
 182
 183        thermal_zone_device_unregister(dove_thermal);
 184        platform_set_drvdata(pdev, NULL);
 185
 186        return 0;
 187}
 188
 189MODULE_DEVICE_TABLE(of, dove_thermal_id_table);
 190
 191static struct platform_driver dove_thermal_driver = {
 192        .probe = dove_thermal_probe,
 193        .remove = dove_thermal_exit,
 194        .driver = {
 195                .name = "dove_thermal",
 196                .owner = THIS_MODULE,
 197                .of_match_table = of_match_ptr(dove_thermal_id_table),
 198        },
 199};
 200
 201module_platform_driver(dove_thermal_driver);
 202
 203MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
 204MODULE_DESCRIPTION("Dove thermal driver");
 205MODULE_LICENSE("GPL");
 206
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