spear_thermal.c
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/*
* SPEAr thermal driver.
*
* Copyright (C) 2011-2012 ST Microelectronics
* Author: Vincenzo Frascino <vincenzo.frascino@st.com>
*
* 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/clk.h>
#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 MD_FACTOR 1000
/* SPEAr Thermal Sensor Dev Structure */
struct spear_thermal_dev {
/* pointer to base address of the thermal sensor */
void __iomem *thermal_base;
/* clk structure */
struct clk *clk;
/* pointer to thermal flags */
unsigned int flags;
};
static inline int thermal_get_temp(struct thermal_zone_device *thermal,
unsigned long *temp)
{
struct spear_thermal_dev *stdev = thermal->devdata;
/*
* Data are ready to be read after 628 usec from POWERDOWN signal
* (PDN) = 1
*/
*temp = (readl_relaxed(stdev->thermal_base) & 0x7F) * MD_FACTOR;
return 0;
}
static struct thermal_zone_device_ops ops = {
.get_temp = thermal_get_temp,
};
#ifdef CONFIG_PM
static int spear_thermal_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
struct spear_thermal_dev *stdev = spear_thermal->devdata;
unsigned int actual_mask = 0;
/* Disable SPEAr Thermal Sensor */
actual_mask = readl_relaxed(stdev->thermal_base);
writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
clk_disable(stdev->clk);
dev_info(dev, "Suspended.\n");
return 0;
}
static int spear_thermal_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
struct spear_thermal_dev *stdev = spear_thermal->devdata;
unsigned int actual_mask = 0;
int ret = 0;
ret = clk_enable(stdev->clk);
if (ret) {
dev_err(&pdev->dev, "Can't enable clock\n");
return ret;
}
/* Enable SPEAr Thermal Sensor */
actual_mask = readl_relaxed(stdev->thermal_base);
writel_relaxed(actual_mask | stdev->flags, stdev->thermal_base);
dev_info(dev, "Resumed.\n");
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(spear_thermal_pm_ops, spear_thermal_suspend,
spear_thermal_resume);
static int spear_thermal_probe(struct platform_device *pdev)
{
struct thermal_zone_device *spear_thermal = NULL;
struct spear_thermal_dev *stdev;
struct device_node *np = pdev->dev.of_node;
struct resource *res;
int ret = 0, val;
if (!np || !of_property_read_u32(np, "st,thermal-flags", &val)) {
dev_err(&pdev->dev, "Failed: DT Pdata not passed\n");
return -EINVAL;
}
stdev = devm_kzalloc(&pdev->dev, sizeof(*stdev), GFP_KERNEL);
if (!stdev) {
dev_err(&pdev->dev, "kzalloc fail\n");
return -ENOMEM;
}
/* Enable thermal sensor */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
stdev->thermal_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(stdev->thermal_base))
return PTR_ERR(stdev->thermal_base);
stdev->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(stdev->clk)) {
dev_err(&pdev->dev, "Can't get clock\n");
return PTR_ERR(stdev->clk);
}
ret = clk_enable(stdev->clk);
if (ret) {
dev_err(&pdev->dev, "Can't enable clock\n");
return ret;
}
stdev->flags = val;
writel_relaxed(stdev->flags, stdev->thermal_base);
spear_thermal = thermal_zone_device_register("spear_thermal", 0, 0,
stdev, &ops, NULL, 0, 0);
if (IS_ERR(spear_thermal)) {
dev_err(&pdev->dev, "thermal zone device is NULL\n");
ret = PTR_ERR(spear_thermal);
goto disable_clk;
}
platform_set_drvdata(pdev, spear_thermal);
dev_info(&spear_thermal->device, "Thermal Sensor Loaded at: 0x%p.\n",
stdev->thermal_base);
return 0;
disable_clk:
clk_disable(stdev->clk);
return ret;
}
static int spear_thermal_exit(struct platform_device *pdev)
{
unsigned int actual_mask = 0;
struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
struct spear_thermal_dev *stdev = spear_thermal->devdata;
thermal_zone_device_unregister(spear_thermal);
/* Disable SPEAr Thermal Sensor */
actual_mask = readl_relaxed(stdev->thermal_base);
writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
clk_disable(stdev->clk);
return 0;
}
static const struct of_device_id spear_thermal_id_table[] = {
{ .compatible = "st,thermal-spear1340" },
{}
};
MODULE_DEVICE_TABLE(of, spear_thermal_id_table);
static struct platform_driver spear_thermal_driver = {
.probe = spear_thermal_probe,
.remove = spear_thermal_exit,
.driver = {
.name = "spear_thermal",
.owner = THIS_MODULE,
.pm = &spear_thermal_pm_ops,
.of_match_table = spear_thermal_id_table,
},
};
module_platform_driver(spear_thermal_driver);
MODULE_AUTHOR("Vincenzo Frascino <vincenzo.frascino@st.com>");
MODULE_DESCRIPTION("SPEAr thermal driver");
MODULE_LICENSE("GPL");