diff options
Diffstat (limited to 'drivers/thermal/kirkwood_thermal.c')
| -rw-r--r-- | drivers/thermal/kirkwood_thermal.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/drivers/thermal/kirkwood_thermal.c b/drivers/thermal/kirkwood_thermal.c new file mode 100644 index 000000000000..65cb4f09e8f6 --- /dev/null +++ b/drivers/thermal/kirkwood_thermal.c @@ -0,0 +1,134 @@ +/* + * 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. See Section 8.10.1 of the 88AP510, + * datasheet, which has the same sensor. + * Documentation/arm/Marvell/README + */ + reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) & + KIRKWOOD_THERMAL_TEMP_MASK; + *temp = ((2281638UL - (7298*reg)) / 10); + + 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; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "Failed to get platform resource\n"); + return -ENODEV; + } + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->sensor = devm_request_and_ioremap(&pdev->dev, res); + if (!priv->sensor) { + dev_err(&pdev->dev, "Failed to request_ioremap memory\n"); + return -EADDRNOTAVAIL; + } + + 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); + platform_set_drvdata(pdev, NULL); + + 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 = of_match_ptr(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"); |