126 lines
3.2 KiB
C
126 lines
3.2 KiB
C
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/*
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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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int *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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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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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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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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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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.of_match_table = 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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