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Linux/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                           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. 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                 .owner = THIS_MODULE,
188                 .of_match_table = dove_thermal_id_table,
189         },
190 };
191 
192 module_platform_driver(dove_thermal_driver);
193 
194 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
195 MODULE_DESCRIPTION("Dove thermal driver");
196 MODULE_LICENSE("GPL");
197 

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