/* * Kirkwood thermal sensor driver * * Copyright (C) 2012 Nobuhiro Iwamatsu <iwamatsu@nigauri.org> * * 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 KIRKWOOD_THERMAL_VALID_OFFSET 9 #define KIRKWOOD_THERMAL_VALID_MASK 0x1 #define KIRKWOOD_THERMAL_TEMP_OFFSET 10 #define KIRKWOOD_THERMAL_TEMP_MASK 0x1FF /* Kirkwood Thermal Sensor Dev Structure */ struct kirkwood_thermal_priv { void __iomem *sensor; }; static int kirkwood_get_temp(struct thermal_zone_device *thermal, unsigned long *temp) { unsigned long reg; struct kirkwood_thermal_priv *priv = thermal->devdata; reg = readl_relaxed(priv->sensor); /* Valid check */ if (!((reg >> KIRKWOOD_THERMAL_VALID_OFFSET) & KIRKWOOD_THERMAL_VALID_MASK)) { 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 = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) & KIRKWOOD_THERMAL_TEMP_MASK; *temp = ((3220000000UL - (10000000UL * reg)) / 13625); return 0; } static struct thermal_zone_device_ops ops = { .get_temp = kirkwood_get_temp, }; static const struct of_device_id kirkwood_thermal_id_table[] = { { .compatible = "marvell,kirkwood-thermal" }, {} }; static int kirkwood_thermal_probe(struct platform_device *pdev) { struct thermal_zone_device *thermal = NULL; struct kirkwood_thermal_priv *priv; struct resource *res; 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); thermal = thermal_zone_device_register("kirkwood_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 kirkwood_thermal_exit(struct platform_device *pdev) { struct thermal_zone_device *kirkwood_thermal = platform_get_drvdata(pdev); thermal_zone_device_unregister(kirkwood_thermal); return 0; } MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table); static struct platform_driver kirkwood_thermal_driver = { .probe = kirkwood_thermal_probe, .remove = kirkwood_thermal_exit, .driver = { .name = "kirkwood_thermal", .owner = THIS_MODULE, .of_match_table = kirkwood_thermal_id_table, }, }; module_platform_driver(kirkwood_thermal_driver); MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>"); MODULE_DESCRIPTION("kirkwood thermal driver"); MODULE_LICENSE("GPL");