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// SPDX-License-Identifier: GPL-2.0-or-later
/* Sparx5 SoC temperature sensor driver
*
* Copyright (C) 2020 Lars Povlsen <lars.povlsen@microchip.com>
*/
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/hwmon.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#define TEMP_CTRL 0
#define TEMP_CFG 4
#define TEMP_CFG_CYCLES GENMASK(24, 15)
#define TEMP_CFG_ENA BIT(0)
#define TEMP_STAT 8
#define TEMP_STAT_VALID BIT(12)
#define TEMP_STAT_TEMP GENMASK(11, 0)
struct s5_hwmon {
void __iomem *base;
struct clk *clk;
};
static void s5_temp_clk_disable(void *data)
{
struct clk *clk = data;
clk_disable_unprepare(clk);
}
static void s5_temp_enable(struct s5_hwmon *hwmon)
{
u32 val = readl(hwmon->base + TEMP_CFG);
u32 clk = clk_get_rate(hwmon->clk) / USEC_PER_SEC;
val &= ~TEMP_CFG_CYCLES;
val |= FIELD_PREP(TEMP_CFG_CYCLES, clk);
val |= TEMP_CFG_ENA;
writel(val, hwmon->base + TEMP_CFG);
}
static int s5_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *temp)
{
struct s5_hwmon *hwmon = dev_get_drvdata(dev);
int rc = 0, value;
u32 stat;
switch (attr) {
case hwmon_temp_input:
stat = readl_relaxed(hwmon->base + TEMP_STAT);
if (!(stat & TEMP_STAT_VALID))
return -EAGAIN;
value = stat & TEMP_STAT_TEMP;
/*
* From register documentation:
* Temp(C) = TEMP_SENSOR_STAT.TEMP / 4096 * 352.2 - 109.4
*/
value = DIV_ROUND_CLOSEST(value * 3522, 4096) - 1094;
/*
* Scale down by 10 from above and multiply by 1000 to
* have millidegrees as specified by the hwmon sysfs
* interface.
*/
value *= 100;
*temp = value;
break;
default:
rc = -EOPNOTSUPP;
break;
}
return rc;
}
static umode_t s5_is_visible(const void *_data, enum hwmon_sensor_types type,
u32 attr, int channel)
{
if (type != hwmon_temp)
return 0;
switch (attr) {
case hwmon_temp_input:
return 0444;
default:
return 0;
}
}
static const struct hwmon_channel_info *s5_info[] = {
HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
NULL
};
static const struct hwmon_ops s5_hwmon_ops = {
.is_visible = s5_is_visible,
.read = s5_read,
};
static const struct hwmon_chip_info s5_chip_info = {
.ops = &s5_hwmon_ops,
.info = s5_info,
};
static int s5_temp_probe(struct platform_device *pdev)
{
struct device *hwmon_dev;
struct s5_hwmon *hwmon;
int ret;
hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
if (!hwmon)
return -ENOMEM;
hwmon->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(hwmon->base))
return PTR_ERR(hwmon->base);
hwmon->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(hwmon->clk))
return PTR_ERR(hwmon->clk);
ret = clk_prepare_enable(hwmon->clk);
if (ret)
return ret;
ret = devm_add_action_or_reset(&pdev->dev, s5_temp_clk_disable,
hwmon->clk);
if (ret)
return ret;
s5_temp_enable(hwmon);
hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
"s5_temp",
hwmon,
&s5_chip_info,
NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct of_device_id s5_temp_match[] = {
{ .compatible = "microchip,sparx5-temp" },
{},
};
MODULE_DEVICE_TABLE(of, s5_temp_match);
static struct platform_driver s5_temp_driver = {
.probe = s5_temp_probe,
.driver = {
.name = "sparx5-temp",
.of_match_table = s5_temp_match,
},
};
module_platform_driver(s5_temp_driver);
MODULE_AUTHOR("Lars Povlsen <lars.povlsen@microchip.com>");
MODULE_DESCRIPTION("Sparx5 SoC temperature sensor driver");
MODULE_LICENSE("GPL");
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