dove_thermal.c
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/*
* Dove thermal sensor driver
*
* Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/thermal.h>
#define DOVE_THERMAL_TEMP_OFFSET 1
#define DOVE_THERMAL_TEMP_MASK 0x1FF
/* Dove Thermal Manager Control and Status Register */
#define PMU_TM_DISABLE_OFFS 0
#define PMU_TM_DISABLE_MASK (0x1 << PMU_TM_DISABLE_OFFS)
/* Dove Theraml Diode Control 0 Register */
#define PMU_TDC0_SW_RST_MASK (0x1 << 1)
#define PMU_TDC0_SEL_VCAL_OFFS 5
#define PMU_TDC0_SEL_VCAL_MASK (0x3 << PMU_TDC0_SEL_VCAL_OFFS)
#define PMU_TDC0_REF_CAL_CNT_OFFS 11
#define PMU_TDC0_REF_CAL_CNT_MASK (0x1FF << PMU_TDC0_REF_CAL_CNT_OFFS)
#define PMU_TDC0_AVG_NUM_OFFS 25
#define PMU_TDC0_AVG_NUM_MASK (0x7 << PMU_TDC0_AVG_NUM_OFFS)
/* Dove Thermal Diode Control 1 Register */
#define PMU_TEMP_DIOD_CTRL1_REG 0x04
#define PMU_TDC1_TEMP_VALID_MASK (0x1 << 10)
/* Dove Thermal Sensor Dev Structure */
struct dove_thermal_priv {
void __iomem *sensor;
void __iomem *control;
};
static int dove_init_sensor(const struct dove_thermal_priv *priv)
{
u32 reg;
u32 i;
/* Configure the Diode Control Register #0 */
reg = readl_relaxed(priv->control);
/* Use average of 2 */
reg &= ~PMU_TDC0_AVG_NUM_MASK;
reg |= (0x1 << PMU_TDC0_AVG_NUM_OFFS);
/* Reference calibration value */
reg &= ~PMU_TDC0_REF_CAL_CNT_MASK;
reg |= (0x0F1 << PMU_TDC0_REF_CAL_CNT_OFFS);
/* Set the high level reference for calibration */
reg &= ~PMU_TDC0_SEL_VCAL_MASK;
reg |= (0x2 << PMU_TDC0_SEL_VCAL_OFFS);
writel(reg, priv->control);
/* Reset the sensor */
reg = readl_relaxed(priv->control);
writel((reg | PMU_TDC0_SW_RST_MASK), priv->control);
writel(reg, priv->control);
/* Enable the sensor */
reg = readl_relaxed(priv->sensor);
reg &= ~PMU_TM_DISABLE_MASK;
writel(reg, priv->sensor);
/* Poll the sensor for the first reading */
for (i = 0; i < 1000000; i++) {
reg = readl_relaxed(priv->sensor);
if (reg & DOVE_THERMAL_TEMP_MASK)
break;
}
if (i == 1000000)
return -EIO;
return 0;
}
static int dove_get_temp(struct thermal_zone_device *thermal,
unsigned long *temp)
{
unsigned long reg;
struct dove_thermal_priv *priv = thermal->devdata;
/* Valid check */
reg = readl_relaxed(priv->control + PMU_TEMP_DIOD_CTRL1_REG);
if ((reg & PMU_TDC1_TEMP_VALID_MASK) == 0x0) {
dev_err(&thermal->device,
"Temperature sensor reading not valid\n");
return -EIO;
}
/*
* Calculate temperature. According to Marvell internal
* documentation the formula for this is:
* Celsius = (322-reg)/1.3625
*/
reg = readl_relaxed(priv->sensor);
reg = (reg >> DOVE_THERMAL_TEMP_OFFSET) & DOVE_THERMAL_TEMP_MASK;
*temp = ((3220000000UL - (10000000UL * reg)) / 13625);
return 0;
}
static struct thermal_zone_device_ops ops = {
.get_temp = dove_get_temp,
};
static const struct of_device_id dove_thermal_id_table[] = {
{ .compatible = "marvell,dove-thermal" },
{}
};
static int dove_thermal_probe(struct platform_device *pdev)
{
struct thermal_zone_device *thermal = NULL;
struct dove_thermal_priv *priv;
struct resource *res;
int ret;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->sensor = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(priv->sensor))
return PTR_ERR(priv->sensor);
res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
priv->control = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(priv->control))
return PTR_ERR(priv->control);
ret = dove_init_sensor(priv);
if (ret) {
dev_err(&pdev->dev, "Failed to initialize sensor\n");
return ret;
}
thermal = thermal_zone_device_register("dove_thermal", 0, 0,
priv, &ops, NULL, 0, 0);
if (IS_ERR(thermal)) {
dev_err(&pdev->dev,
"Failed to register thermal zone device\n");
return PTR_ERR(thermal);
}
platform_set_drvdata(pdev, thermal);
return 0;
}
static int dove_thermal_exit(struct platform_device *pdev)
{
struct thermal_zone_device *dove_thermal =
platform_get_drvdata(pdev);
thermal_zone_device_unregister(dove_thermal);
return 0;
}
MODULE_DEVICE_TABLE(of, dove_thermal_id_table);
static struct platform_driver dove_thermal_driver = {
.probe = dove_thermal_probe,
.remove = dove_thermal_exit,
.driver = {
.name = "dove_thermal",
.owner = THIS_MODULE,
.of_match_table = dove_thermal_id_table,
},
};
module_platform_driver(dove_thermal_driver);
MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
MODULE_DESCRIPTION("Dove thermal driver");
MODULE_LICENSE("GPL");