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			  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
121static struct thermal_zone_device_ops ops = {
122	.get_temp = dove_get_temp,
123};
124
125static const struct of_device_id dove_thermal_id_table[] = {
126	{ .compatible = "marvell,dove-thermal" },
127	{}
128};
129
130static 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
170static 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
180MODULE_DEVICE_TABLE(of, dove_thermal_id_table);
181
182static 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
191module_platform_driver(dove_thermal_driver);
192
193MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
194MODULE_DESCRIPTION("Dove thermal driver");
195MODULE_LICENSE("GPL");