drivers/thermal/dove_thermal.c

   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 */
  46 struct dove_thermal_priv {
  47         void __iomem *sensor;
  48         void __iomem *control;
  49 };
  50
  51 static 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
  95 static int dove_get_temp(struct thermal_zone_device *thermal,
  96                           int *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. According to Marvell internal
 111          * documentation the formula for this is:
 112          * Celsius = (322-reg)/1.3625
 113          */
 114         reg = readl_relaxed(priv->sensor);
 115         reg = (reg >> DOVE_THERMAL_TEMP_OFFSET) & DOVE_THERMAL_TEMP_MASK;
 116         *temp = ((3220000000UL - (10000000UL * reg)) / 13625);
 117
 118         return 0;
 119 }
 120
 121 static struct thermal_zone_device_ops ops = {
 122         .get_temp = dove_get_temp,
 123 };
 124
 125 static const struct of_device_id dove_thermal_id_table[] = {
 126         { .compatible = "marvell,dove-thermal" },
 127         {}
 128 };
 129
 130 static int dove_thermal_probe(struct platform_device *pdev)
 131 {
 132         struct thermal_zone_device *thermal = NULL;
 133         struct dove_thermal_priv *priv;
 134         struct resource *res;
 135         int ret;
 136
 137         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 138         if (!priv)
 139                 return -ENOMEM;
 140
 141         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 142         priv->sensor = devm_ioremap_resource(&pdev->dev, res);
 143         if (IS_ERR(priv->sensor))
 144                 return PTR_ERR(priv->sensor);
 145
 146         res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 147         priv->control = devm_ioremap_resource(&pdev->dev, res);
 148         if (IS_ERR(priv->control))
 149                 return PTR_ERR(priv->control);
 150
 151         ret = dove_init_sensor(priv);
 152         if (ret) {
 153                 dev_err(&pdev->dev, "Failed to initialize sensor\n");
 154                 return ret;
 155         }
 156
 157         thermal = thermal_zone_device_register("dove_thermal", 0, 0,
 158                                                priv, &ops, NULL, 0, 0);
 159         if (IS_ERR(thermal)) {
 160                 dev_err(&pdev->dev,
 161                         "Failed to register thermal zone device\n");
 162                 return PTR_ERR(thermal);
 163         }
 164
 165         platform_set_drvdata(pdev, thermal);
 166
 167         return 0;
 168 }
 169
 170 static int dove_thermal_exit(struct platform_device *pdev)
 171 {
 172         struct thermal_zone_device *dove_thermal =
 173                 platform_get_drvdata(pdev);
 174
 175         thermal_zone_device_unregister(dove_thermal);
 176
 177         return 0;
 178 }
 179
 180 MODULE_DEVICE_TABLE(of, dove_thermal_id_table);
 181
 182 static struct platform_driver dove_thermal_driver = {
 183         .probe = dove_thermal_probe,
 184         .remove = dove_thermal_exit,
 185         .driver = {
 186                 .name = "dove_thermal",
 187                 .of_match_table = dove_thermal_id_table,
 188         },
 189 };
 190
 191 module_platform_driver(dove_thermal_driver);
 192
 193 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
 194 MODULE_DESCRIPTION("Dove thermal driver");
 195 MODULE_LICENSE("GPL");