linux-imx

// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * acerhdf - A driver which monitors the temperature

 *           of the aspire one netbook, turns on/off the fan

 *           as soon as the upper/lower threshold is reached.

 *

 * (C) 2009 - Peter Feuerer     peter (a) piie.net

 *                              http://piie.net

 *     2009 Borislav Petkov bp (a) alien8.de

 *

 * Inspired by and many thanks to:

 *  o acerfand   - Rachel Greenham

 *  o acer_ec.pl - Michael Kurz     michi.kurz (at) googlemail.com

 *               - Petr Tomasek     tomasek (#) etf,cuni,cz

 *               - Carlos Corbacho  cathectic (at) gmail.com

 *  o lkml       - Matthew Garrett

 *               - Borislav Petkov

 *               - Andreas Mohr

 */

​

#define pr_fmt(fmt) "acerhdf: " fmt

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/dmi.h>

#include <linux/acpi.h>

#include <linux/thermal.h>

#include <linux/platform_device.h>

​

/*

 * The driver is started with "kernel mode off" by default. That means, the BIOS

 * is still in control of the fan. In this mode the driver allows to read the

 * temperature of the cpu and a userspace tool may take over control of the fan.

 * If the driver is switched to "kernel mode" (e.g. via module parameter) the

 * driver is in full control of the fan. If you want the module to be started in

 * kernel mode by default, define the following:

 */

#undef START_IN_KERNEL_MODE

​

#define DRV_VER "0.7.0"

​

/*

 * According to the Atom N270 datasheet,

 * (http://download.intel.com/design/processor/datashts/320032.pdf) the

 * CPU's optimal operating limits denoted in junction temperature as

 * measured by the on-die thermal monitor are within 0 <= Tj <= 90. So,

 * assume 89°C is critical temperature.

 */

#define ACERHDF_TEMP_CRIT 89000

#define ACERHDF_FAN_OFF 0

#define ACERHDF_FAN_AUTO 1

​

/*

 * No matter what value the user puts into the fanon variable, turn on the fan

 * at 80 degree Celsius to prevent hardware damage

 */

#define ACERHDF_MAX_FANON 80000

​

/*

 * Maximum interval between two temperature checks is 15 seconds, as the die

 * can get hot really fast under heavy load (plus we shouldn't forget about

 * possible impact of _external_ aggressive sources such as heaters, sun etc.)

 */