696b6075af
The currently formula has been taken from the 88AP510 SoC datasheet, which is not exactly correct. The correct value for the temperature in Celcius of the sensor present in this SoC is: Celsius = (322-reg)/1.3625 Signed-off-by: Lior Amsalem <alior@marvell.com> Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com> Acked-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
133 lines
3.4 KiB
C
133 lines
3.4 KiB
C
/*
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* Kirkwood thermal sensor driver
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*
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* Copyright (C) 2012 Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/of.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/thermal.h>
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#define KIRKWOOD_THERMAL_VALID_OFFSET 9
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#define KIRKWOOD_THERMAL_VALID_MASK 0x1
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#define KIRKWOOD_THERMAL_TEMP_OFFSET 10
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#define KIRKWOOD_THERMAL_TEMP_MASK 0x1FF
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/* Kirkwood Thermal Sensor Dev Structure */
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struct kirkwood_thermal_priv {
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void __iomem *sensor;
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};
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static int kirkwood_get_temp(struct thermal_zone_device *thermal,
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unsigned long *temp)
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{
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unsigned long reg;
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struct kirkwood_thermal_priv *priv = thermal->devdata;
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reg = readl_relaxed(priv->sensor);
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/* Valid check */
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if (!((reg >> KIRKWOOD_THERMAL_VALID_OFFSET) &
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KIRKWOOD_THERMAL_VALID_MASK)) {
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dev_err(&thermal->device,
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"Temperature sensor reading not valid\n");
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return -EIO;
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}
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/*
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* Calculate temperature. According to Marvell internal
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* documentation the formula for this is:
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* Celsius = (322-reg)/1.3625
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*/
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reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) &
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KIRKWOOD_THERMAL_TEMP_MASK;
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*temp = ((3220000000UL - (10000000UL * reg)) / 13625);
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return 0;
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}
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static struct thermal_zone_device_ops ops = {
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.get_temp = kirkwood_get_temp,
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};
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static const struct of_device_id kirkwood_thermal_id_table[] = {
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{ .compatible = "marvell,kirkwood-thermal" },
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{}
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};
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static int kirkwood_thermal_probe(struct platform_device *pdev)
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{
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struct thermal_zone_device *thermal = NULL;
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struct kirkwood_thermal_priv *priv;
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struct resource *res;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res) {
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dev_err(&pdev->dev, "Failed to get platform resource\n");
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return -ENODEV;
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}
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->sensor = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(priv->sensor))
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return PTR_ERR(priv->sensor);
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thermal = thermal_zone_device_register("kirkwood_thermal", 0, 0,
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priv, &ops, NULL, 0, 0);
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if (IS_ERR(thermal)) {
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dev_err(&pdev->dev,
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"Failed to register thermal zone device\n");
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return PTR_ERR(thermal);
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}
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platform_set_drvdata(pdev, thermal);
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return 0;
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}
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static int kirkwood_thermal_exit(struct platform_device *pdev)
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{
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struct thermal_zone_device *kirkwood_thermal =
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platform_get_drvdata(pdev);
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thermal_zone_device_unregister(kirkwood_thermal);
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platform_set_drvdata(pdev, NULL);
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return 0;
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}
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MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table);
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static struct platform_driver kirkwood_thermal_driver = {
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.probe = kirkwood_thermal_probe,
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.remove = kirkwood_thermal_exit,
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.driver = {
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.name = "kirkwood_thermal",
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.owner = THIS_MODULE,
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.of_match_table = of_match_ptr(kirkwood_thermal_id_table),
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},
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};
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module_platform_driver(kirkwood_thermal_driver);
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MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>");
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MODULE_DESCRIPTION("kirkwood thermal driver");
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MODULE_LICENSE("GPL");
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