// SPDX-License-Identifier: GPL-2.0-only
/*
 * Windfarm PowerMac thermal control. iMac G5 iSight
 *
 * (c) Copyright 2007 Étienne Bersac <bersace@gmail.com>
 *
 * Bits & pieces from windfarm_pm81.c by (c) Copyright 2005 Benjamin
 * Herrenschmidt, IBM Corp. <benh@kernel.crashing.org>
 *
 * PowerMac12,1
 * ============
 *
 * The algorithm used is the PID control algorithm, used the same way
 * the published Darwin code does, using the same values that are
 * present in the Darwin 8.10 snapshot property lists (note however
 * that none of the code has been re-used, it's a complete
 * re-implementation
 *
 * There is two models using PowerMac12,1. Model 2 is iMac G5 iSight
 * 17" while Model 3 is iMac G5 20". They do have both the same
 * controls with a tiny difference. The control-ids of hard-drive-fan
 * and cpu-fan is swapped.
 *
 * Target Correction :
 *
 * controls have a target correction calculated as :
 *
 * new_min = ((((average_power * slope) >> 16) + offset) >> 16) + min_value
 * new_value = max(new_value, max(new_min, 0))
 *
 * OD Fan control correction.
 *
 * # model_id: 2
 *   offset             : -19563152
 *   slope              :  1956315
 *
 * # model_id: 3
 *   offset             : -15650652
 *   slope              :  1565065
 *
 * HD Fan control correction.
 *
 * # model_id: 2
 *   offset             : -15650652
 *   slope              :  1565065
 *
 * # model_id: 3
 *   offset             : -19563152
 *   slope              :  1956315
 *
 * CPU Fan control correction.
 *
 * # model_id: 2
 *   offset             : -25431900
 *   slope              :  2543190
 *
 * # model_id: 3
 *   offset             : -15650652
 *   slope              :  1565065
 *
 * Target rubber-banding :
 *
 * Some controls have a target correction which depends on another
 * control value. The correction is computed in the following way :
 *
 * new_min = ref_value * slope + offset
 *
 * ref_value is the value of the reference control. If new_min is
 * greater than 0, then we correct the target value using :
 *
 * new_target = max (new_target, new_min >> 16)
 *
 * # model_id : 2
 *   control    : cpu-fan
 *   ref        : optical-drive-fan
 *   offset     : -15650652
 *   slope      : 1565065
 *
 * # model_id : 3
 *   control    : optical-drive-fan
 *   ref        : hard-drive-fan
 *   offset     : -32768000
 *   slope      : 65536
 *
 * In order to have the moste efficient correction with those
 * dependencies, we must trigger HD loop before OD loop before CPU
 * loop.
 *
 * The various control loops found in Darwin config file are:
 *
 * HD Fan control loop.
 *
 * # model_id: 2
 *   control        : hard-drive-fan
 *   sensor         : hard-drive-temp
 *   PID params     : G_d = 0x00000000
 *                    G_p = 0x002D70A3
 *                    G_r = 0x00019999
 *                    History = 2 entries
 *                    Input target = 0x370000
 *                    Interval = 5s
 *
 * # model_id: 3
 *   control        : hard-drive-fan
 *   sensor         : hard-drive-temp
 *   PID params     : G_d = 0x00000000
 *                    G_p = 0x002170A3
 *                    G_r = 0x00019999
 *                    History = 2 entries
 *                    Input target = 0x370000
 *                    Interval = 5s
 *
 * OD Fan control loop.
 *
 * # model_id: 2
 *   control        : optical-drive-fan
 *   sensor         : optical-drive-temp
 *   PID params     : G_d = 0x00000000
 *                    G_p = 0x001FAE14
 *                    G_r = 0x00019999
 *                    History = 2 entries
 *                    Input target = 0x320000
 *                    Interval = 5s
 *
 * # model_id: 3
 *   control        : optical-drive-fan
 *   sensor         : optical-drive-temp
 *   PID params     : G_d = 0x00000000
 *                    G_p = 0x001FAE14
 *                    G_r = 0x00019999
 *                    History = 2 entries
 *                    Input target = 0x320000
 *                    Interval = 5s
 *
 * GPU Fan control loop.
 *
 * # model_id: 2
 *   control        : hard-drive-fan
 *   sensor         : gpu-temp
 *   PID params     : G_d = 0x00000000
 *                    G_p = 0x002A6666
 *                    G_r = 0x00019999
 *                    History = 2 entries
 *                    Input target = 0x5A0000
 *                    Interval = 5s
 *
 * # model_id: 3
 *   control        : cpu-fan
 *   sensor         : gpu-temp
 *   PID params     : G_d = 0x00000000
 *                    G_p = 0x0010CCCC
 *                    G_r = 0x00019999
 *                    History = 2 entries
 *                    Input target = 0x500000
 *                    Interval = 5s
 *
 * KODIAK (aka northbridge) Fan control loop.
 *
 * # model_id: 2
 *   control        : optical-drive-fan
 *   sensor         : north-bridge-temp
 *   PID params     : G_d = 0x00000000
 *                    G_p = 0x003BD70A
 *                    G_r = 0x00019999
 *                    History = 2 entries
 *                    Input target = 0x550000
 *                    Interval = 5s
 *
 * # model_id: 3
 *   control        : hard-drive-fan
 *   sensor         : north-bridge-temp
 *   PID params     : G_d = 0x00000000
 *                    G_p = 0x0030F5C2
 *                    G_r = 0x00019999
 *                    History = 2 entries
 *                    Input target = 0x550000
 *                    Interval = 5s
 *
 * CPU Fan control loop.
 *
 *   control        : cpu-fan
 *   sensors        : cpu-temp, cpu-power
 *   PID params     : from SDB partition
 *
 * CPU Slew control loop.
 *
 *   control        : cpufreq-clamp
 *   sensor         : cpu-temp
 */

#undef  DEBUG

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/kmod.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/of.h>

#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/sections.h>
#include <asm/smu.h>

#include "windfarm.h"
#include "windfarm_pid.h"

#define VERSION "0.3"

static int pm121_mach_model;    /* machine model id */

/* Controls & sensors */
static struct wf_sensor *sensor_cpu_power;
static struct wf_sensor *sensor_cpu_temp;
static struct wf_sensor *sensor_cpu_voltage;
static struct wf_sensor *sensor_cpu_current;
static struct wf_sensor *sensor_gpu_temp;
static struct wf_sensor *sensor_north_bridge_temp;
static struct wf_sensor *sensor_hard_drive_temp;
static struct wf_sensor *sensor_optical_drive_temp;
static struct wf_sensor *sensor_incoming_air_temp; /* unused ! */

enum {
        FAN_CPU,
        FAN_HD,
        FAN_OD,
        CPUFREQ,
        N_CONTROLS
};
static struct wf_control *controls[N_CONTROLS] = {};

/* Set to kick the control loop into life */
static int pm121_all_controls_ok, pm121_all_sensors_ok;
static bool pm121_started;

enum {
        FAILURE_FAN             = 1 << 0,
        FAILURE_SENSOR          = 1 << 1,
        FAILURE_OVERTEMP        = 1 << 2
};

/* All sys loops. Note the HD before the OD loop in order to have it
   run before. */
enum {
        LOOP_GPU,               /* control = hd or cpu, but luckily,
                                   it doesn't matter */
        LOOP_HD,                /* control = hd */
        LOOP_KODIAK,            /* control = hd or od */
        LOOP_OD,                /* control = od */
        N_LOOPS
};

static const char *loop_names[N_LOOPS] = {
        "GPU",
        "HD",
        "KODIAK",
        "OD",
};

#define PM121_NUM_CONFIGS       2

static unsigned int pm121_failure_state;
static int pm121_readjust, pm121_skipping;
static bool pm121_overtemp;
static s32 average_power;

struct pm121_correction {
        int     offset;
        int     slope;
};

static struct pm121_correction corrections[N_CONTROLS][PM121_NUM_CONFIGS] = {
        /* FAN_OD */
        {
                /* MODEL 2 */
                { .offset       = -19563152,
                  .slope        =  1956315
                },
                /* MODEL 3 */
                { .offset       = -15650652,
                  .slope        =  1565065
                },
        },
        /* FAN_HD */
        {
                /* MODEL 2 */
                { .offset       = -15650652,
                  .slope        =  1565065
                },
                /* MODEL 3 */
                { .offset       = -19563152,
                  .slope        =  1956315
                },
        },
        /* FAN_CPU */
        {
                /* MODEL 2 */
                { .offset       = -25431900,
                  .slope        =  2543190
                },
                /* MODEL 3 */
                { .offset       = -15650652,
                  .slope        =  1565065
                },
        },
        /* CPUFREQ has no correction (and is not implemented at all) */
};

struct pm121_connection {
        unsigned int    control_id;
        unsigned int    ref_id;
        struct pm121_correction correction;
};

static struct pm121_connection pm121_connections[] = {
        /* MODEL 2 */
        { .control_id   = FAN_CPU,
          .ref_id       = FAN_OD,
          { .offset     = -32768000,
            .slope      =  65536
          }
        },
        /* MODEL 3 */
        { .control_id   = FAN_OD,
          .ref_id       = FAN_HD,
          { .offset     = -32768000,
            .slope      =  65536
          }
        },
};

/* pointer to the current model connection */
static struct pm121_connection *pm121_connection;

/*
 * ****** System Fans Control Loop ******
 *
 */

/* Since each loop handles only one control and we want to avoid
 * writing virtual control, we store the control correction with the
 * loop params. Some data are not set, there are common to all loop
 * and thus, hardcoded.
 */
struct pm121_sys_param {
        /* purely informative since we use mach_model-2 as index */
        int                     model_id;
        struct wf_sensor        **sensor; /* use sensor_id instead ? */
        s32                     gp, itarget;
        unsigned int            control_id;
};

static struct pm121_sys_param
pm121_sys_all_params[N_LOOPS][PM121_NUM_CONFIGS] = {
        /* GPU Fan control loop */
        {
                { .model_id     = 2,
                  .sensor       = &sensor_gpu_temp,
                  .gp           = 0x002A6666,
                  .itarget      = 0x5A0000,
                  .control_id   = FAN_HD,
                },
                { .model_id     = 3,
                  .sensor       = &sensor_gpu_temp,
                  .gp           = 0x0010CCCC,
                  .itarget      = 0x500000,
                  .control_id   = FAN_CPU,
                },
        },
        /* HD Fan control loop */
        {
                { .model_id     = 2,
                  .sensor       = &sensor_hard_drive_temp,
                  .gp           = 0x002D70A3,
                  .itarget      = 0x370000,
                  .control_id   = FAN_HD,
                },
                { .model_id     = 3,
                  .sensor       = &sensor_hard_drive_temp,
                  .gp           = 0x002170A3,
                  .itarget      = 0x370000,
                  .control_id   = FAN_HD,
                },
        },
        /* KODIAK Fan control loop */
        {
                { .model_id     = 2,
                  .sensor       = &sensor_north_bridge_temp,
                  .gp           = 0x003BD70A,
                  .itarget      = 0x550000,
                  .control_id   = FAN_OD,
                },
                { .model_id     = 3,
                  .sensor       = &sensor_north_bridge_temp,
                  .gp           = 0x0030F5C2,
                  .itarget      = 0x550000,
                  .control_id   = FAN_HD,
                },
        },
        /* OD Fan control loop */
        {
                { .model_id     = 2,
                  .sensor       = &sensor_optical_drive_temp,
                  .gp           = 0x001FAE14,
                  .itarget      = 0x320000,
                  .control_id   = FAN_OD,
                },
                { .model_id     = 3,
                  .sensor       = &sensor_optical_drive_temp,
                  .gp           = 0x001FAE14,
                  .itarget      = 0x320000,
                  .control_id   = FAN_OD,
                },
        },
};

/* the hardcoded values */
#define PM121_SYS_GD            0x00000000
#define PM121_SYS_GR            0x00019999
#define PM121_SYS_HISTORY_SIZE  2
#define PM121_SYS_INTERVAL      5

/* State data used by the system fans control loop
 */
struct pm121_sys_state {
        int                     ticks;
        s32                     setpoint;
        struct wf_pid_state     pid;
};

static struct pm121_sys_state *pm121_sys_state[N_LOOPS] = {};

/*
 * ****** CPU Fans Control Loop ******
 *
 */

#define PM121_CPU_INTERVAL      1

/* State data used by the cpu fans control loop
 */
struct pm121_cpu_state {
        int                     ticks;
        s32                     setpoint;
        struct wf_cpu_pid_state pid;
};

static struct pm121_cpu_state *pm121_cpu_state;



/*
 * ***** Implementation *****
 *
 */

/* correction the value using the output-low-bound correction algo */
static s32 pm121_correct(s32 new_setpoint,
                         unsigned int control_id,
                         s32 min)
{
        s32 new_min;
        struct pm121_correction *correction;
        correction = &corrections[control_id][pm121_mach_model - 2];

        new_min = (average_power * correction->slope) >> 16;
        new_min += correction->offset;
        new_min = (new_min >> 16) + min;

        return max3(new_setpoint, new_min, 0);
}

static s32 pm121_connect(unsigned int control_id, s32 setpoint)
{
        s32 new_min, value, new_setpoint;

        if (pm121_connection->control_id == control_id) {
                controls[control_id]->ops->get_value(controls[control_id],
                                                     &value);
                new_min = value * pm121_connection->correction.slope;
                new_min += pm121_connection->correction.offset;
                if (new_min > 0) {
                        new_setpoint = max(setpoint, (new_min >> 16));
                        if (new_setpoint != setpoint) {
                                pr_debug("pm121: %s depending on %s, "
                                         "corrected from %d to %d RPM\n",
                                         controls[control_id]->name,
                                         controls[pm121_connection->ref_id]->name,
                                         (int) setpoint, (int) new_setpoint);
                        }
                } else
                        new_setpoint = setpoint;
        }
        /* no connection */
        else
                new_setpoint = setpoint;

        return new_setpoint;
}

/* FAN LOOPS */
static void pm121_create_sys_fans(int loop_id)
{
        struct pm121_sys_param *param = NULL;
        struct wf_pid_param pid_param;
        struct wf_control *control = NULL;
        int i;

        /* First, locate the params for this model */
        for (i = 0; i < PM121_NUM_CONFIGS; i++) {
                if (pm121_sys_all_params[loop_id][i].model_id == pm121_mach_model) {
                        param = &(pm121_sys_all_params[loop_id][i]);
                        break;
                }
        }

        /* No params found, put fans to max */
        if (param == NULL) {
                printk(KERN_WARNING "pm121: %s fan config not found "
                       " for this machine model\n",
                       loop_names[loop_id]);
                goto fail;
        }

        control = controls[param->control_id];

        /* Alloc & initialize state */
        pm121_sys_state[loop_id] = kmalloc_obj(struct pm121_sys_state);
        if (pm121_sys_state[loop_id] == NULL) {
                printk(KERN_WARNING "pm121: Memory allocation error\n");
                goto fail;
        }
        pm121_sys_state[loop_id]->ticks = 1;

        /* Fill PID params */
        pid_param.gd            = PM121_SYS_GD;
        pid_param.gp            = param->gp;
        pid_param.gr            = PM121_SYS_GR;
        pid_param.interval      = PM121_SYS_INTERVAL;
        pid_param.history_len   = PM121_SYS_HISTORY_SIZE;
        pid_param.itarget       = param->itarget;
        if(control)
        {
                pid_param.min           = control->ops->get_min(control);
                pid_param.max           = control->ops->get_max(control);
        } else {
                /*
                 * This is probably not the right!?
                 * Perhaps goto fail  if control == NULL  above?
                 */
                pid_param.min           = 0;
                pid_param.max           = 0;
        }

        wf_pid_init(&pm121_sys_state[loop_id]->pid, &pid_param);

        pr_debug("pm121: %s Fan control loop initialized.\n"
                 "       itarged=%d.%03d, min=%d RPM, max=%d RPM\n",
                 loop_names[loop_id], FIX32TOPRINT(pid_param.itarget),
                 pid_param.min, pid_param.max);
        return;

 fail:
        /* note that this is not optimal since another loop may still
           control the same control */
        printk(KERN_WARNING "pm121: failed to set up %s loop "
               "setting \"%s\" to max speed.\n",
               loop_names[loop_id], control ? control->name : "uninitialized value");

        if (control)
                wf_control_set_max(control);
}

static void pm121_sys_fans_tick(int loop_id)
{
        struct pm121_sys_param *param;
        struct pm121_sys_state *st;
        struct wf_sensor *sensor;
        struct wf_control *control;
        s32 temp, new_setpoint;
        int rc;

        param = &(pm121_sys_all_params[loop_id][pm121_mach_model-2]);
        st = pm121_sys_state[loop_id];
        sensor = *(param->sensor);
        control = controls[param->control_id];

        if (--st->ticks != 0) {
                if (pm121_readjust)
                        goto readjust;
                return;
        }
        st->ticks = PM121_SYS_INTERVAL;

        rc = sensor->ops->get_value(sensor, &temp);
        if (rc) {
                printk(KERN_WARNING "windfarm: %s sensor error %d\n",
                       sensor->name, rc);
                pm121_failure_state |= FAILURE_SENSOR;
                return;
        }

        pr_debug("pm121: %s Fan tick ! %s: %d.%03d\n",
                 loop_names[loop_id], sensor->name,
                 FIX32TOPRINT(temp));

        new_setpoint = wf_pid_run(&st->pid, temp);

        /* correction */
        new_setpoint = pm121_correct(new_setpoint,
                                     param->control_id,
                                     st->pid.param.min);
        /* linked corretion */
        new_setpoint = pm121_connect(param->control_id, new_setpoint);

        if (new_setpoint == st->setpoint)
                return;
        st->setpoint = new_setpoint;
        pr_debug("pm121: %s corrected setpoint: %d RPM\n",
                 control->name, (int)new_setpoint);
 readjust:
        if (control && pm121_failure_state == 0) {
                rc = control->ops->set_value(control, st->setpoint);
                if (rc) {
                        printk(KERN_WARNING "windfarm: %s fan error %d\n",
                               control->name, rc);
                        pm121_failure_state |= FAILURE_FAN;
                }
        }
}


/* CPU LOOP */
static void pm121_create_cpu_fans(void)
{
        struct wf_cpu_pid_param pid_param;
        const struct smu_sdbp_header *hdr;
        struct smu_sdbp_cpupiddata *piddata;
        struct smu_sdbp_fvt *fvt;
        struct wf_control *fan_cpu;
        s32 tmax, tdelta, maxpow, powadj;

        fan_cpu = controls[FAN_CPU];

        /* First, locate the PID params in SMU SBD */
        hdr = smu_get_sdb_partition(SMU_SDB_CPUPIDDATA_ID, NULL);
        if (!hdr) {
                printk(KERN_WARNING "pm121: CPU PID fan config not found.\n");
                goto fail;
        }
        piddata = (struct smu_sdbp_cpupiddata *)&hdr[1];

        /* Get the FVT params for operating point 0 (the only supported one
         * for now) in order to get tmax
         */
        hdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);
        if (hdr) {
                fvt = (struct smu_sdbp_fvt *)&hdr[1];
                tmax = ((s32)fvt->maxtemp) << 16;
        } else
                tmax = 0x5e0000; /* 94 degree default */

        /* Alloc & initialize state */
        pm121_cpu_state = kmalloc_obj(struct pm121_cpu_state);
        if (pm121_cpu_state == NULL)
                goto fail;
        pm121_cpu_state->ticks = 1;

        /* Fill PID params */
        pid_param.interval = PM121_CPU_INTERVAL;
        pid_param.history_len = piddata->history_len;
        if (pid_param.history_len > WF_CPU_PID_MAX_HISTORY) {
                printk(KERN_WARNING "pm121: History size overflow on "
                       "CPU control loop (%d)\n", piddata->history_len);
                pid_param.history_len = WF_CPU_PID_MAX_HISTORY;
        }
        pid_param.gd = piddata->gd;
        pid_param.gp = piddata->gp;
        pid_param.gr = piddata->gr / pid_param.history_len;

        tdelta = ((s32)piddata->target_temp_delta) << 16;
        maxpow = ((s32)piddata->max_power) << 16;
        powadj = ((s32)piddata->power_adj) << 16;

        pid_param.tmax = tmax;
        pid_param.ttarget = tmax - tdelta;
        pid_param.pmaxadj = maxpow - powadj;

        pid_param.min = fan_cpu->ops->get_min(fan_cpu);
        pid_param.max = fan_cpu->ops->get_max(fan_cpu);

        wf_cpu_pid_init(&pm121_cpu_state->pid, &pid_param);

        pr_debug("pm121: CPU Fan control initialized.\n");
        pr_debug("       ttarget=%d.%03d, tmax=%d.%03d, min=%d RPM, max=%d RPM,\n",
                 FIX32TOPRINT(pid_param.ttarget), FIX32TOPRINT(pid_param.tmax),
                 pid_param.min, pid_param.max);

        return;

 fail:
        printk(KERN_WARNING "pm121: CPU fan config not found, max fan speed\n");

        if (controls[CPUFREQ])
                wf_control_set_max(controls[CPUFREQ]);
        if (fan_cpu)
                wf_control_set_max(fan_cpu);
}


static void pm121_cpu_fans_tick(struct pm121_cpu_state *st)
{
        s32 new_setpoint, temp, power;
        struct wf_control *fan_cpu = NULL;
        int rc;

        if (--st->ticks != 0) {
                if (pm121_readjust)
                        goto readjust;
                return;
        }
        st->ticks = PM121_CPU_INTERVAL;

        fan_cpu = controls[FAN_CPU];

        rc = sensor_cpu_temp->ops->get_value(sensor_cpu_temp, &temp);
        if (rc) {
                printk(KERN_WARNING "pm121: CPU temp sensor error %d\n",
                       rc);
                pm121_failure_state |= FAILURE_SENSOR;
                return;
        }

        rc = sensor_cpu_power->ops->get_value(sensor_cpu_power, &power);
        if (rc) {
                printk(KERN_WARNING "pm121: CPU power sensor error %d\n",
                       rc);
                pm121_failure_state |= FAILURE_SENSOR;
                return;
        }

        pr_debug("pm121: CPU Fans tick ! CPU temp: %d.%03d°C, power: %d.%03d\n",
                 FIX32TOPRINT(temp), FIX32TOPRINT(power));

        if (temp > st->pid.param.tmax)
                pm121_failure_state |= FAILURE_OVERTEMP;

        new_setpoint = wf_cpu_pid_run(&st->pid, power, temp);

        /* correction */
        new_setpoint = pm121_correct(new_setpoint,
                                     FAN_CPU,
                                     st->pid.param.min);

        /* connected correction */
        new_setpoint = pm121_connect(FAN_CPU, new_setpoint);

        if (st->setpoint == new_setpoint)
                return;
        st->setpoint = new_setpoint;
        pr_debug("pm121: CPU corrected setpoint: %d RPM\n", (int)new_setpoint);

 readjust:
        if (fan_cpu && pm121_failure_state == 0) {
                rc = fan_cpu->ops->set_value(fan_cpu, st->setpoint);
                if (rc) {
                        printk(KERN_WARNING "pm121: %s fan error %d\n",
                               fan_cpu->name, rc);
                        pm121_failure_state |= FAILURE_FAN;
                }
        }
}

/*
 * ****** Common ******
 *
 */

static void pm121_tick(void)
{
        unsigned int last_failure = pm121_failure_state;
        unsigned int new_failure;
        s32 total_power;
        int i;

        if (!pm121_started) {
                pr_debug("pm121: creating control loops !\n");
                for (i = 0; i < N_LOOPS; i++)
                        pm121_create_sys_fans(i);

                pm121_create_cpu_fans();
                pm121_started = true;
        }

        /* skipping ticks */
        if (pm121_skipping && --pm121_skipping)
                return;

        /* compute average power */
        total_power = 0;
        for (i = 0; i < pm121_cpu_state->pid.param.history_len; i++)
                total_power += pm121_cpu_state->pid.powers[i];

        average_power = total_power / pm121_cpu_state->pid.param.history_len;


        pm121_failure_state = 0;
        for (i = 0 ; i < N_LOOPS; i++) {
                if (pm121_sys_state[i])
                        pm121_sys_fans_tick(i);
        }

        if (pm121_cpu_state)
                pm121_cpu_fans_tick(pm121_cpu_state);

        pm121_readjust = 0;
        new_failure = pm121_failure_state & ~last_failure;

        /* If entering failure mode, clamp cpufreq and ramp all
         * fans to full speed.
         */
        if (pm121_failure_state && !last_failure) {
                for (i = 0; i < N_CONTROLS; i++) {
                        if (controls[i])
                                wf_control_set_max(controls[i]);
                }
        }

        /* If leaving failure mode, unclamp cpufreq and readjust
         * all fans on next iteration
         */
        if (!pm121_failure_state && last_failure) {
                if (controls[CPUFREQ])
                        wf_control_set_min(controls[CPUFREQ]);
                pm121_readjust = 1;
        }

        /* Overtemp condition detected, notify and start skipping a couple
         * ticks to let the temperature go down
         */
        if (new_failure & FAILURE_OVERTEMP) {
                wf_set_overtemp();
                pm121_skipping = 2;
                pm121_overtemp = true;
        }

        /* We only clear the overtemp condition if overtemp is cleared
         * _and_ no other failure is present. Since a sensor error will
         * clear the overtemp condition (can't measure temperature) at
         * the control loop levels, but we don't want to keep it clear
         * here in this case
         */
        if (!pm121_failure_state && pm121_overtemp) {
                wf_clear_overtemp();
                pm121_overtemp = false;
        }
}


static struct wf_control* pm121_register_control(struct wf_control *ct,
                                                 const char *match,
                                                 unsigned int id)
{
        if (controls[id] == NULL && !strcmp(ct->name, match)) {
                if (wf_get_control(ct) == 0)
                        controls[id] = ct;
        }
        return controls[id];
}

static void pm121_new_control(struct wf_control *ct)
{
        int all = 1;

        if (pm121_all_controls_ok)
                return;

        all = pm121_register_control(ct, "optical-drive-fan", FAN_OD) && all;
        all = pm121_register_control(ct, "hard-drive-fan", FAN_HD) && all;
        all = pm121_register_control(ct, "cpu-fan", FAN_CPU) && all;
        all = pm121_register_control(ct, "cpufreq-clamp", CPUFREQ) && all;

        if (all)
                pm121_all_controls_ok = 1;
}




static struct wf_sensor* pm121_register_sensor(struct wf_sensor *sensor,
                                               const char *match,
                                               struct wf_sensor **var)
{
        if (*var == NULL && !strcmp(sensor->name, match)) {
                if (wf_get_sensor(sensor) == 0)
                        *var = sensor;
        }
        return *var;
}

static void pm121_new_sensor(struct wf_sensor *sr)
{
        int all = 1;

        if (pm121_all_sensors_ok)
                return;

        all = pm121_register_sensor(sr, "cpu-temp",
                                    &sensor_cpu_temp) && all;
        all = pm121_register_sensor(sr, "cpu-current",
                                    &sensor_cpu_current) && all;
        all = pm121_register_sensor(sr, "cpu-voltage",
                                    &sensor_cpu_voltage) && all;
        all = pm121_register_sensor(sr, "cpu-power",
                                    &sensor_cpu_power) && all;
        all = pm121_register_sensor(sr, "hard-drive-temp",
                                    &sensor_hard_drive_temp) && all;
        all = pm121_register_sensor(sr, "optical-drive-temp",
                                    &sensor_optical_drive_temp) && all;
        all = pm121_register_sensor(sr, "incoming-air-temp",
                                    &sensor_incoming_air_temp) && all;
        all = pm121_register_sensor(sr, "north-bridge-temp",
                                    &sensor_north_bridge_temp) && all;
        all = pm121_register_sensor(sr, "gpu-temp",
                                    &sensor_gpu_temp) && all;

        if (all)
                pm121_all_sensors_ok = 1;
}



static int pm121_notify(struct notifier_block *self,
                        unsigned long event, void *data)
{
        switch (event) {
        case WF_EVENT_NEW_CONTROL:
                pr_debug("pm121: new control %s detected\n",
                         ((struct wf_control *)data)->name);
                pm121_new_control(data);
                break;
        case WF_EVENT_NEW_SENSOR:
                pr_debug("pm121: new sensor %s detected\n",
                         ((struct wf_sensor *)data)->name);
                pm121_new_sensor(data);
                break;
        case WF_EVENT_TICK:
                if (pm121_all_controls_ok && pm121_all_sensors_ok)
                        pm121_tick();
                break;
        }

        return 0;
}

static struct notifier_block pm121_events = {
        .notifier_call  = pm121_notify,
};

static int pm121_init_pm(void)
{
        const struct smu_sdbp_header *hdr;

        hdr = smu_get_sdb_partition(SMU_SDB_SENSORTREE_ID, NULL);
        if (hdr) {
                struct smu_sdbp_sensortree *st =
                        (struct smu_sdbp_sensortree *)&hdr[1];
                pm121_mach_model = st->model_id;
        }

        pm121_connection = &pm121_connections[pm121_mach_model - 2];

        printk(KERN_INFO "pm121: Initializing for iMac G5 iSight model ID %d\n",
               pm121_mach_model);

        return 0;
}


static int pm121_probe(struct platform_device *ddev)
{
        wf_register_client(&pm121_events);

        return 0;
}

static void pm121_remove(struct platform_device *ddev)
{
        wf_unregister_client(&pm121_events);
}

static struct platform_driver pm121_driver = {
        .probe = pm121_probe,
        .remove = pm121_remove,
        .driver = {
                .name = "windfarm",
                .bus = &platform_bus_type,
        },
};


static int __init pm121_init(void)
{
        int rc = -ENODEV;

        if (of_machine_is_compatible("PowerMac12,1"))
                rc = pm121_init_pm();

        if (rc == 0) {
                request_module("windfarm_smu_controls");
                request_module("windfarm_smu_sensors");
                request_module("windfarm_smu_sat");
                request_module("windfarm_lm75_sensor");
                request_module("windfarm_max6690_sensor");
                request_module("windfarm_cpufreq_clamp");
                platform_driver_register(&pm121_driver);
        }

        return rc;
}

static void __exit pm121_exit(void)
{

        platform_driver_unregister(&pm121_driver);
}


module_init(pm121_init);
module_exit(pm121_exit);

MODULE_AUTHOR("Étienne Bersac <bersace@gmail.com>");
MODULE_DESCRIPTION("Thermal control logic for iMac G5 (iSight)");
MODULE_LICENSE("GPL");