text: // 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 Kaestle     peter (a) piie.net
   *                              https://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.)
   */
  #define ACERHDF_MAX_INTERVAL 15
  
  #ifdef START_IN_KERNEL_MODE
  static int kernelmode = 1;
  #else
  static int kernelmode;
  #endif
  
  static unsigned int interval = 10;
  static unsigned int fanon = 60000;
  static unsigned int fanoff = 53000;
  static unsigned int verbose;
  static unsigned int list_supported;
  static unsigned int fanstate = ACERHDF_FAN_AUTO;
  static char force_bios[16];
  static char force_product[16];
  static unsigned int prev_interval;
  static struct thermal_zone_device *thz_dev;
  static struct thermal_cooling_device *cl_dev;
  static struct platform_device *acerhdf_dev;
  
  module_param(kernelmode, uint, 0);
  MODULE_PARM_DESC(kernelmode, "Kernel mode fan control on / off");
  module_param(interval, uint, 0600);
  MODULE_PARM_DESC(interval, "Polling interval of temperature check");
  module_param(fanon, uint, 0600);
  MODULE_PARM_DESC(fanon, "Turn the fan on above this temperature");
  module_param(fanoff, uint, 0600);
  MODULE_PARM_DESC(fanoff, "Turn the fan off below this temperature");
  module_param(verbose, uint, 0600);
  MODULE_PARM_DESC(verbose, "Enable verbose dmesg output");
  module_param(list_supported, uint, 0600);
  MODULE_PARM_DESC(list_supported, "List supported models and BIOS versions");
  module_param_string(force_bios, force_bios, 16, 0);
  MODULE_PARM_DESC(force_bios, "Pretend system has this known supported BIOS version");
  module_param_string(force_product, force_product, 16, 0);
  MODULE_PARM_DESC(force_product, "Pretend system is this known supported model");
  
  /*
   * cmd_off: to switch the fan completely off and check if the fan is off
   *	cmd_auto: to set the BIOS in control of the fan. The BIOS regulates then
   *		the fan speed depending on the temperature
   */
  struct fancmd {
  	u8 cmd_off;
  	u8 cmd_auto;
  };
  
  struct manualcmd {
  	u8 mreg;
  	u8 moff;
  };
  
  /* default register and command to disable fan in manual mode */
  static const struct manualcmd mcmd = {
  	.mreg = 0x94,
  	.moff = 0xff,
  };
  
  /* BIOS settings - only used during probe */
  struct bios_settings {
  	const char *vendor;
  	const char *product;
  	const char *version;
  	u8 fanreg;
  	u8 tempreg;
  	struct fancmd cmd;
  	int mcmd_enable;
  };
  
  /* This could be a daughter struct in the above, but not worth the redirect */
  struct ctrl_settings {
  	u8 fanreg;
  	u8 tempreg;
  	struct fancmd cmd;
  	int mcmd_enable;
  };
  
  static struct ctrl_settings ctrl_cfg __read_mostly;
  
  /* Register addresses and values for different BIOS versions */
  static const struct bios_settings bios_tbl[] __initconst = {
  	/* AOA110 */
  	{"Acer", "AOA110", "v0.3109", 0x55, 0x58, {0x1f, 0x00}, 0},
  	{"Acer", "AOA110", "v0.3114", 0x55, 0x58, {0x1f, 0x00}, 0},
  	{"Acer", "AOA110", "v0.3301", 0x55, 0x58, {0xaf, 0x00}, 0},
  	{"Acer", "AOA110", "v0.3304", 0x55, 0x58, {0xaf, 0x00}, 0},
  	{"Acer", "AOA110", "v0.3305", 0x55, 0x58, {0xaf, 0x00}, 0},
  	{"Acer", "AOA110", "v0.3307", 0x55, 0x58, {0xaf, 0x00}, 0},
  	{"Acer", "AOA110", "v0.3308", 0x55, 0x58, {0x21, 0x00}, 0},
  	{"Acer", "AOA110", "v0.3309", 0x55, 0x58, {0x21, 0x00}, 0},
  	{"Acer", "AOA110", "v0.3310", 0x55, 0x58, {0x21, 0x00}, 0},
  	/* AOA150 */
  	{"Acer", "AOA150", "v0.3114", 0x55, 0x58, {0x1f, 0x00}, 0},
  	{"Acer", "AOA150", "v0.3301", 0x55, 0x58, {0x20, 0x00}, 0},
  	{"Acer", "AOA150", "v0.3304", 0x55, 0x58, {0x20, 0x00}, 0},
  	{"Acer", "AOA150", "v0.3305", 0x55, 0x58, {0x20, 0x00}, 0},
  	{"Acer", "AOA150", "v0.3307", 0x55, 0x58, {0x20, 0x00}, 0},
  	{"Acer", "AOA150", "v0.3308", 0x55, 0x58, {0x20, 0x00}, 0},
  	{"Acer", "AOA150", "v0.3309", 0x55, 0x58, {0x20, 0x00}, 0},
  	{"Acer", "AOA150", "v0.3310", 0x55, 0x58, {0x20, 0x00}, 0},
  	/* LT1005u */
  	{"Acer", "LT-10Q", "v0.3310", 0x55, 0x58, {0x20, 0x00}, 0},
  	/* Acer 1410 */
  	{"Acer", "Aspire 1410", "v0.3108", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1410", "v0.3113", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1410", "v0.3115", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1410", "v0.3117", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1410", "v0.3119", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1410", "v0.3120", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1410", "v1.3204", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1410", "v1.3303", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1410", "v1.3308", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1410", "v1.3310", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1410", "v1.3314", 0x55, 0x58, {0x9e, 0x00}, 0},
  	/* Acer 1810xx */
  	{"Acer", "Aspire 1810TZ", "v0.3108", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810T",  "v0.3108", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810TZ", "v0.3113", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810T",  "v0.3113", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810TZ", "v0.3115", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810T",  "v0.3115", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810TZ", "v0.3117", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810T",  "v0.3117", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810TZ", "v0.3119", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810T",  "v0.3119", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810TZ", "v0.3120", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810T",  "v0.3120", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810TZ", "v1.3204", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810T",  "v1.3204", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810TZ", "v1.3303", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810T",  "v1.3303", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810TZ", "v1.3308", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810T",  "v1.3308", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810TZ", "v1.3310", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810T",  "v1.3310", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810TZ", "v1.3314", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1810T",  "v1.3314", 0x55, 0x58, {0x9e, 0x00}, 0},
  	/* Acer 5755G */
  	{"Acer", "Aspire 5755G",  "V1.20",   0xab, 0xb4, {0x00, 0x08}, 0},
  	{"Acer", "Aspire 5755G",  "V1.21",   0xab, 0xb3, {0x00, 0x08}, 0},
  	/* Acer 521 */
  	{"Acer", "AO521", "V1.11", 0x55, 0x58, {0x1f, 0x00}, 0},
  	/* Acer 531 */
  	{"Acer", "AO531h", "v0.3104", 0x55, 0x58, {0x20, 0x00}, 0},
  	{"Acer", "AO531h", "v0.3201", 0x55, 0x58, {0x20, 0x00}, 0},
  	{"Acer", "AO531h", "v0.3304", 0x55, 0x58, {0x20, 0x00}, 0},
  	/* Acer 751 */
  	{"Acer", "AO751h", "V0.3206", 0x55, 0x58, {0x21, 0x00}, 0},
  	{"Acer", "AO751h", "V0.3212", 0x55, 0x58, {0x21, 0x00}, 0},
  	/* Acer 753 */
  	{"Acer", "Aspire One 753", "V1.24", 0x93, 0xac, {0x14, 0x04}, 1},
  	/* Acer 1825 */
  	{"Acer", "Aspire 1825PTZ", "V1.3118", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Acer", "Aspire 1825PTZ", "V1.3127", 0x55, 0x58, {0x9e, 0x00}, 0},
  	/* Acer Extensa 5420 */
  	{"Acer", "Extensa 5420", "V1.17", 0x93, 0xac, {0x14, 0x04}, 1},
  	/* Acer Aspire 5315 */
  	{"Acer", "Aspire 5315", "V1.19", 0x93, 0xac, {0x14, 0x04}, 1},
  	/* Acer Aspire 5739 */
  	{"Acer", "Aspire 5739G", "V1.3311", 0x55, 0x58, {0x20, 0x00}, 0},
  	/* Acer TravelMate 7730 */
  	{"Acer", "TravelMate 7730G", "v0.3509", 0x55, 0x58, {0xaf, 0x00}, 0},
  	/* Acer Aspire 7551 */
  	{"Acer", "Aspire 7551", "V1.18", 0x93, 0xa8, {0x14, 0x04}, 1},
  	/* Acer TravelMate TM8573T */
  	{"Acer", "TM8573T", "V1.13", 0x93, 0xa8, {0x14, 0x04}, 1},
  	/* Gateway */
  	{"Gateway", "AOA110", "v0.3103",  0x55, 0x58, {0x21, 0x00}, 0},
  	{"Gateway", "AOA150", "v0.3103",  0x55, 0x58, {0x20, 0x00}, 0},
  	{"Gateway", "LT31",   "v1.3103",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Gateway", "LT31",   "v1.3201",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Gateway", "LT31",   "v1.3302",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Gateway", "LT31",   "v1.3303t", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Gateway", "LT31",   "v1.3307",  0x55, 0x58, {0x9e, 0x00}, 0},
  	/* Packard Bell */
  	{"Packard Bell", "DOA150",  "v0.3104",  0x55, 0x58, {0x21, 0x00}, 0},
  	{"Packard Bell", "DOA150",  "v0.3105",  0x55, 0x58, {0x20, 0x00}, 0},
  	{"Packard Bell", "AOA110",  "v0.3105",  0x55, 0x58, {0x21, 0x00}, 0},
  	{"Packard Bell", "AOA150",  "v0.3105",  0x55, 0x58, {0x20, 0x00}, 0},
  	{"Packard Bell", "ENBFT",   "V1.3118",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "ENBFT",   "V1.3127",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTMU",   "v1.3303",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTMU",   "v0.3120",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTMU",   "v0.3108",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTMU",   "v0.3113",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTMU",   "v0.3115",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTMU",   "v0.3117",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTMU",   "v0.3119",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTMU",   "v1.3204",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTMA",   "v1.3201",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTMA",   "v1.3302",  0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTMA",   "v1.3303t", 0x55, 0x58, {0x9e, 0x00}, 0},
  	{"Packard Bell", "DOTVR46", "v1.3308",  0x55, 0x58, {0x9e, 0x00}, 0},
  	/* pewpew-terminator */
  	{"", "", "", 0, 0, {0, 0}, 0}
  };
  
  /*
   * this struct is used to instruct thermal layer to use bang_bang instead of
   * default governor for acerhdf
   */
  static struct thermal_zone_params acerhdf_zone_params = {
  	.governor_name = "bang_bang",
  };
  
  static int acerhdf_get_temp(int *temp)
  {
  	u8 read_temp;
  
  	if (ec_read(ctrl_cfg.tempreg, &read_temp))
  		return -EINVAL;
  
  	*temp = read_temp * 1000;
  
  	return 0;
  }
  
  static int acerhdf_get_fanstate(int *state)
  {
  	u8 fan;
  
  	if (ec_read(ctrl_cfg.fanreg, &fan))
  		return -EINVAL;
  
  	if (fan != ctrl_cfg.cmd.cmd_off)
  		*state = ACERHDF_FAN_AUTO;
  	else
  		*state = ACERHDF_FAN_OFF;
  
  	return 0;
  }
  
  static void acerhdf_change_fanstate(int state)
  {
  	unsigned char cmd;
  
  	if (verbose)
  		pr_notice("fan %s\n", state == ACERHDF_FAN_OFF ? "OFF" : "ON");
  
  	if ((state != ACERHDF_FAN_OFF) && (state != ACERHDF_FAN_AUTO)) {
  		pr_err("invalid fan state %d requested, setting to auto!\n",
  		       state);
  		state = ACERHDF_FAN_AUTO;
  	}
  
  	cmd = (state == ACERHDF_FAN_OFF) ? ctrl_cfg.cmd.cmd_off
  					 : ctrl_cfg.cmd.cmd_auto;
  	fanstate = state;
  
  	ec_write(ctrl_cfg.fanreg, cmd);
  
  	if (ctrl_cfg.mcmd_enable && state == ACERHDF_FAN_OFF) {
  		if (verbose)
  			pr_notice("turning off fan manually\n");
  		ec_write(mcmd.mreg, mcmd.moff);
  	}
  }
  
  static void acerhdf_check_param(struct thermal_zone_device *thermal)
  {
  	if (fanon > ACERHDF_MAX_FANON) {
  		pr_err("fanon temperature too high, set to %d\n",
  		       ACERHDF_MAX_FANON);
  		fanon = ACERHDF_MAX_FANON;
  	}
  
  	if (kernelmode && prev_interval != interval) {
  		if (interval > ACERHDF_MAX_INTERVAL) {
  			pr_err("interval too high, set to %d\n",
  			       ACERHDF_MAX_INTERVAL);
  			interval = ACERHDF_MAX_INTERVAL;
  		}
  		if (verbose)
  			pr_notice("interval changed to: %d\n", interval);
  		thermal->polling_delay = interval*1000;
  		prev_interval = interval;
  	}
  }
  
  /*
   * This is the thermal zone callback which does the delayed polling of the fan
   * state. We do check /sysfs-originating settings here in acerhdf_check_param()
   * as late as the polling interval is since we can't do that in the respective
   * accessors of the module parameters.
   */
  static int acerhdf_get_ec_temp(struct thermal_zone_device *thermal, int *t)
  {
  	int temp, err = 0;
  
  	acerhdf_check_param(thermal);
  
  	err = acerhdf_get_temp(&temp);
  	if (err)
  		return err;
  
  	if (verbose)
  		pr_notice("temp %d\n", temp);
  
  	*t = temp;
  	return 0;
  }
  
  static int acerhdf_bind(struct thermal_zone_device *thermal,
  			struct thermal_cooling_device *cdev)
  {
  	/* if the cooling device is the one from acerhdf bind it */
  	if (cdev != cl_dev)
  		return 0;
  
  	if (thermal_zone_bind_cooling_device(thermal, 0, cdev,
  			THERMAL_NO_LIMIT, THERMAL_NO_LIMIT,
  			THERMAL_WEIGHT_DEFAULT)) {
  		pr_err("error binding cooling dev\n");
  		return -EINVAL;
  	}
  	return 0;
  }
  
  static int acerhdf_unbind(struct thermal_zone_device *thermal,
  			  struct thermal_cooling_device *cdev)
  {
  	if (cdev != cl_dev)
  		return 0;
  
  	if (thermal_zone_unbind_cooling_device(thermal, 0, cdev)) {
  		pr_err("error unbinding cooling dev\n");
  		return -EINVAL;
  	}
  	return 0;
  }
  
  static inline void acerhdf_revert_to_bios_mode(void)
  {
  	acerhdf_change_fanstate(ACERHDF_FAN_AUTO);
  	kernelmode = 0;
  
  	pr_notice("kernel mode fan control OFF\n");
  }
  static inline void acerhdf_enable_kernelmode(void)
  {
  	kernelmode = 1;
  
  	pr_notice("kernel mode fan control ON\n");
  }
  
  /*
   * set operation mode;
   * enabled: the thermal layer of the kernel takes care about
   *          the temperature and the fan.
   * disabled: the BIOS takes control of the fan.
   */
  static int acerhdf_change_mode(struct thermal_zone_device *thermal,
  			       enum thermal_device_mode mode)
  {
  	if (mode == THERMAL_DEVICE_DISABLED && kernelmode)
  		acerhdf_revert_to_bios_mode();
  	else if (mode == THERMAL_DEVICE_ENABLED && !kernelmode)
  		acerhdf_enable_kernelmode();
  
  	return 0;
  }
  
  static int acerhdf_get_trip_type(struct thermal_zone_device *thermal, int trip,
  				 enum thermal_trip_type *type)
  {
  	if (trip == 0)
  		*type = THERMAL_TRIP_ACTIVE;
  	else if (trip == 1)
  		*type = THERMAL_TRIP_CRITICAL;
  	else
  		return -EINVAL;
  
  	return 0;
  }
  
  static int acerhdf_get_trip_hyst(struct thermal_zone_device *thermal, int trip,
  				 int *temp)
  {
  	if (trip != 0)
  		return -EINVAL;
  
  	*temp = fanon - fanoff;
  
  	return 0;
  }
  
  static int acerhdf_get_trip_temp(struct thermal_zone_device *thermal, int trip,
  				 int *temp)
  {
  	if (trip == 0)
  		*temp = fanon;
  	else if (trip == 1)
  		*temp = ACERHDF_TEMP_CRIT;
  	else
  		return -EINVAL;
  
  	return 0;
  }
  
  static int acerhdf_get_crit_temp(struct thermal_zone_device *thermal,
  				 int *temperature)
  {
  	*temperature = ACERHDF_TEMP_CRIT;
  	return 0;
  }
  
  /* bind callback functions to thermalzone */
  static struct thermal_zone_device_ops acerhdf_dev_ops = {
  	.bind = acerhdf_bind,
  	.unbind = acerhdf_unbind,
  	.get_temp = acerhdf_get_ec_temp,
  	.change_mode = acerhdf_change_mode,
  	.get_trip_type = acerhdf_get_trip_type,
  	.get_trip_hyst = acerhdf_get_trip_hyst,
  	.get_trip_temp = acerhdf_get_trip_temp,
  	.get_crit_temp = acerhdf_get_crit_temp,
  };
  
  
  /*
   * cooling device callback functions
   * get maximal fan cooling state
   */
  static int acerhdf_get_max_state(struct thermal_cooling_device *cdev,
  				 unsigned long *state)
  {
  	*state = 1;
  
  	return 0;
  }
  
  static int acerhdf_get_cur_state(struct thermal_cooling_device *cdev,
  				 unsigned long *state)
  {
  	int err = 0, tmp;
  
  	err = acerhdf_get_fanstate(&tmp);
  	if (err)
  		return err;
  
  	*state = (tmp == ACERHDF_FAN_AUTO) ? 1 : 0;
  	return 0;
  }
  
  /* change current fan state - is overwritten when running in kernel mode */
  static int acerhdf_set_cur_state(struct thermal_cooling_device *cdev,
  				 unsigned long state)
  {
  	int cur_temp, cur_state, err = 0;
  
  	if (!kernelmode)
  		return 0;
  
  	err = acerhdf_get_temp(&cur_temp);
  	if (err) {
  		pr_err("error reading temperature, hand off control to BIOS\n");
  		goto err_out;
  	}
  
  	err = acerhdf_get_fanstate(&cur_state);
  	if (err) {
  		pr_err("error reading fan state, hand off control to BIOS\n");
  		goto err_out;
  	}
  
  	if (state == 0) {
  		if (cur_state == ACERHDF_FAN_AUTO)
  			acerhdf_change_fanstate(ACERHDF_FAN_OFF);
  	} else {
  		if (cur_state == ACERHDF_FAN_OFF)
  			acerhdf_change_fanstate(ACERHDF_FAN_AUTO);
  	}
  	return 0;
  
  err_out:
  	acerhdf_revert_to_bios_mode();
  	return -EINVAL;
  }
  
  /* bind fan callbacks to fan device */
  static const struct thermal_cooling_device_ops acerhdf_cooling_ops = {
  	.get_max_state = acerhdf_get_max_state,
  	.get_cur_state = acerhdf_get_cur_state,
  	.set_cur_state = acerhdf_set_cur_state,
  };
  
  /* suspend / resume functionality */
  static int acerhdf_suspend(struct device *dev)
  {
  	if (kernelmode)
  		acerhdf_change_fanstate(ACERHDF_FAN_AUTO);
  
  	if (verbose)
  		pr_notice("going suspend\n");
  
  	return 0;
  }
  
  static int acerhdf_probe(struct platform_device *device)
  {
  	return 0;
  }
  
  static int acerhdf_remove(struct platform_device *device)
  {
  	return 0;
  }
  
  static const struct dev_pm_ops acerhdf_pm_ops = {
  	.suspend = acerhdf_suspend,
  	.freeze  = acerhdf_suspend,
  };
  
  static struct platform_driver acerhdf_driver = {
  	.driver = {
  		.name  = "acerhdf",
  		.pm    = &acerhdf_pm_ops,
  	},
  	.probe = acerhdf_probe,
  	.remove = acerhdf_remove,
  };
  
  /* checks if str begins with start */
  static int str_starts_with(const char *str, const char *start)
  {
  	unsigned long str_len = 0, start_len = 0;
  
  	str_len = strlen(str);
  	start_len = strlen(start);
  
  	if (str_len >= start_len &&
  			!strncmp(str, start, start_len))
  		return 1;
  
  	return 0;
  }
  
  /* check hardware */
  static int __init acerhdf_check_hardware(void)
  {
  	char const *vendor, *version, *product;
  	const struct bios_settings *bt = NULL;
  	int found = 0;
  
  	/* get BIOS data */
  	vendor  = dmi_get_system_info(DMI_SYS_VENDOR);
  	version = dmi_get_system_info(DMI_BIOS_VERSION);
  	product = dmi_get_system_info(DMI_PRODUCT_NAME);
  
  	if (!vendor || !version || !product) {
  		pr_err("error getting hardware information\n");
  		return -EINVAL;
  	}
  
  	pr_info("Acer Aspire One Fan driver, v.%s\n", DRV_VER);
  
  	if (list_supported) {
  		pr_info("List of supported Manufacturer/Model/BIOS:\n");
  		pr_info("---------------------------------------------------\n");
  		for (bt = bios_tbl; bt->vendor[0]; bt++) {
  			pr_info("%-13s | %-17s | %-10s\n", bt->vendor,
  				bt->product, bt->version);
  		}
  		pr_info("---------------------------------------------------\n");
  		return -ECANCELED;
  	}
  
  	if (force_bios[0]) {
  		version = force_bios;
  		pr_info("forcing BIOS version: %s\n", version);
  		kernelmode = 0;
  	}
  
  	if (force_product[0]) {
  		product = force_product;
  		pr_info("forcing BIOS product: %s\n", product);
  		kernelmode = 0;
  	}
  
  	if (verbose)
  		pr_info("BIOS info: %s %s, product: %s\n",
  			vendor, version, product);
  
  	/* search BIOS version and vendor in BIOS settings table */
  	for (bt = bios_tbl; bt->vendor[0]; bt++) {
  		/*
  		 * check if actual hardware BIOS vendor, product and version
  		 * IDs start with the strings of BIOS table entry
  		 */
  		if (str_starts_with(vendor, bt->vendor) &&
  				str_starts_with(product, bt->product) &&
  				str_starts_with(version, bt->version)) {
  			found = 1;
  			break;
  		}
  	}
  
  	if (!found) {
  		pr_err("unknown (unsupported) BIOS version %s/%s/%s, please report, aborting!\n",
  		       vendor, product, version);
  		return -EINVAL;
  	}
  
  	/* Copy control settings from BIOS table before we free it. */
  	ctrl_cfg.fanreg = bt->fanreg;
  	ctrl_cfg.tempreg = bt->tempreg;
  	memcpy(&ctrl_cfg.cmd, &bt->cmd, sizeof(struct fancmd));
  	ctrl_cfg.mcmd_enable = bt->mcmd_enable;
  
  	/*
  	 * if started with kernel mode off, prevent the kernel from switching
  	 * off the fan
  	 */
  	if (!kernelmode) {
  		pr_notice("Fan control off, to enable do:\n");
  		pr_notice("echo -n \"enabled\" > /sys/class/thermal/thermal_zoneN/mode # N=0,1,2...\n");
  	}
  
  	return 0;
  }
  
  static int __init acerhdf_register_platform(void)
  {
  	int err = 0;
  
  	err = platform_driver_register(&acerhdf_driver);
  	if (err)
  		return err;
  
  	acerhdf_dev = platform_device_alloc("acerhdf", -1);
  	if (!acerhdf_dev) {
  		err = -ENOMEM;
  		goto err_device_alloc;
  	}
  	err = platform_device_add(acerhdf_dev);
  	if (err)
  		goto err_device_add;
  
  	return 0;
  
  err_device_add:
  	platform_device_put(acerhdf_dev);
  err_device_alloc:
  	platform_driver_unregister(&acerhdf_driver);
  	return err;
  }
  
  static void acerhdf_unregister_platform(void)
  {
  	platform_device_unregister(acerhdf_dev);
  	platform_driver_unregister(&acerhdf_driver);
  }
  
  static int __init acerhdf_register_thermal(void)
  {
  	int ret;
  
  	cl_dev = thermal_cooling_device_register("acerhdf-fan", NULL,
  						 &acerhdf_cooling_ops);
  
  	if (IS_ERR(cl_dev))
  		return -EINVAL;
  
  	thz_dev = thermal_zone_device_register("acerhdf", 2, 0, NULL,
  					      &acerhdf_dev_ops,
  					      &acerhdf_zone_params, 0,
  					      (kernelmode) ? interval*1000 : 0);
  	if (IS_ERR(thz_dev))
  		return -EINVAL;
  
  	if (kernelmode)
  		ret = thermal_zone_device_enable(thz_dev);
  	else
  		ret = thermal_zone_device_disable(thz_dev);
  	if (ret)
  		return ret;
  
  	if (strcmp(thz_dev->governor->name,
  				acerhdf_zone_params.governor_name)) {
  		pr_err("Didn't get thermal governor %s, perhaps not compiled into thermal subsystem.\n",
  				acerhdf_zone_params.governor_name);
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static void acerhdf_unregister_thermal(void)
  {
  	if (cl_dev) {
  		thermal_cooling_device_unregister(cl_dev);
  		cl_dev = NULL;
  	}
  
  	if (thz_dev) {
  		thermal_zone_device_unregister(thz_dev);
  		thz_dev = NULL;
  	}
  }
  
  static int __init acerhdf_init(void)
  {
  	int err = 0;
  
  	err = acerhdf_check_hardware();
  	if (err)
  		goto out_err;
  
  	err = acerhdf_register_platform();
  	if (err)
  		goto out_err;
  
  	err = acerhdf_register_thermal();
  	if (err)
  		goto err_unreg;
  
  	return 0;
  
  err_unreg:
  	acerhdf_unregister_thermal();
  	acerhdf_unregister_platform();
  
  out_err:
  	return err;
  }
  
  static void __exit acerhdf_exit(void)
  {
  	acerhdf_change_fanstate(ACERHDF_FAN_AUTO);
  	acerhdf_unregister_thermal();
  	acerhdf_unregister_platform();
  }
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Peter Kaestle");
  MODULE_DESCRIPTION("Aspire One temperature and fan driver");
  MODULE_ALIAS("dmi:*:*Acer*:pnAOA*:");
  MODULE_ALIAS("dmi:*:*Acer*:pnAO751h*:");
  MODULE_ALIAS("dmi:*:*Acer*:pnAspire*1410*:");
  MODULE_ALIAS("dmi:*:*Acer*:pnAspire*1810*:");
  MODULE_ALIAS("dmi:*:*Acer*:pnAspire*5755G:");
  MODULE_ALIAS("dmi:*:*Acer*:pnAspire*1825PTZ:");
  MODULE_ALIAS("dmi:*:*Acer*:pnAO521*:");
  MODULE_ALIAS("dmi:*:*Acer*:pnAO531*:");
  MODULE_ALIAS("dmi:*:*Acer*:pnAspire*5739G:");
  MODULE_ALIAS("dmi:*:*Acer*:pnAspire*One*753:");
  MODULE_ALIAS("dmi:*:*Acer*:pnAspire*5315:");
  MODULE_ALIAS("dmi:*:*Acer*:TravelMate*7730G:");
  MODULE_ALIAS("dmi:*:*Acer*:pnAspire*7551:");
  MODULE_ALIAS("dmi:*:*Acer*:TM8573T:");
  MODULE_ALIAS("dmi:*:*Gateway*:pnAOA*:");
  MODULE_ALIAS("dmi:*:*Gateway*:pnLT31*:");
  MODULE_ALIAS("dmi:*:*Packard*Bell*:pnAOA*:");
  MODULE_ALIAS("dmi:*:*Packard*Bell*:pnDOA*:");
  MODULE_ALIAS("dmi:*:*Packard*Bell*:pnDOTMU*:");
  MODULE_ALIAS("dmi:*:*Packard*Bell*:pnENBFT*:");
  MODULE_ALIAS("dmi:*:*Packard*Bell*:pnDOTMA*:");
  MODULE_ALIAS("dmi:*:*Packard*Bell*:pnDOTVR46*:");
  MODULE_ALIAS("dmi:*:*Acer*:pnExtensa*5420*:");
  
  module_init(acerhdf_init);
  module_exit(acerhdf_exit);
  