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