ACPI fan

[Jukka Ruohonen <jruohonen%iki.fi@localhost>]

Hi,

below you will find a small driver for controlling ACPI fans. A
sysctl-solution with "knobs" is hardly optimal and in a way the whole driver
is redundant.

However, I have a laptop that has problems with fans and overheating. The
driver provides a manual solution for these immediate problems (at least I
feel more comfortable doing longer debugging sessions with the ability to
turn the fan on). For the record: instead of acpitz(4), fans and thermal
zones seem to be handled directly by the EC.

P.S.

I noticed (too late) that Jared had already written this years ago, so
nothing new here, but someone with similar problems might benefit from this.

* * *

/*      $NetBSD: acpi_fan.c,v 0.1 2009/04/12 11:03:00 $ */

/*-
 * Copyright (c) 2009 Jukka Ruohonen <jruohonen%iki.fi@localhost>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: acpi_fan.c,v 0.1 2009/04/12 11:03:03 $");

#include <sys/param.h>
#include <sys/device.h>
#include <sys/sysctl.h>

#include <dev/acpi/acpireg.h>
#include <dev/acpi/acpivar.h>

struct acpifan_softc {
        struct acpi_devnode *sc_node;
        struct sysctllog    *sc_log;
        device_t             sc_dev;
};

static int         acpifan_match(device_t, cfdata_t, void *);
static void        acpifan_attach(device_t, device_t, void *);
static ACPI_STATUS acpifan_get_state(ACPI_HANDLE, int *);
static ACPI_STATUS acpifan_get_status(ACPI_HANDLE, int *);
static bool        acpifan_sysctl_init(device_t);
static int         acpifan_sysctl_helper(SYSCTLFN_PROTO);

CFATTACH_DECL_NEW(acpifan, sizeof(struct acpifan_softc),
    acpifan_match, acpifan_attach, NULL, NULL);

static const char * const fan_hid[] = {
        "PNP0C0B",
        NULL
};

static int
acpifan_match(device_t parent, cfdata_t match, void *aux)
{
        struct acpi_attach_args *aa = aux;

        if (aa->aa_node->ad_type != ACPI_TYPE_DEVICE)
                return 0;

        return acpi_match_hid(aa->aa_node->ad_devinfo, fan_hid);
}

static void
acpifan_attach(device_t parent, device_t self, void *aux)
{
        struct acpifan_softc *sc = device_private(self);
        struct acpi_attach_args *aa = aux;
        ACPI_STATUS rv;

        sc->sc_dev = self;
        sc->sc_node = aa->aa_node;

        rv = acpifan_get_state(sc->sc_node->ad_handle, NULL);

        if (ACPI_FAILURE(rv)) {
                aprint_normal(": failed to get state: %s\n",
                    AcpiFormatException(rv));
                return;
        }

        aprint_naive(": ACPI Fan\n");
        aprint_normal(": ACPI Fan\n");

        if (acpifan_sysctl_init(self) != true)
                aprint_error_dev(self, "failed to initialize sysctl\n");

        if (pmf_device_register(self, NULL, NULL) != true)
                aprint_error_dev(self, "failed to register power handler\n");
}

static ACPI_STATUS
acpifan_get_state(ACPI_HANDLE hdl, int *state)
{
        ACPI_OBJECT *pobj, *eobj;
        ACPI_BUFFER buf;
        ACPI_STATUS rv;
        uint8_t i, n;

        rv = acpi_eval_struct(hdl, "_PR0", &buf);

        if (ACPI_FAILURE(rv))
                goto out;

        pobj = buf.Pointer;

        if (pobj->Package.Count > 0xFF) {
                rv = AE_LIMIT;
                goto out;
        }

        n = pobj->Package.Count;

        if (pobj->Type != ACPI_TYPE_PACKAGE || n == 0) {
                rv = AE_BAD_DATA;
                goto out;
        }

        eobj = pobj->Package.Elements;

        for (i = 0; i < n; ++i) {

                rv = acpifan_get_status(eobj->Reference.Handle, state);

                if (ACPI_FAILURE(rv))
                        goto out;
                /*
                 * If and only if all resources are "on",
                 * the whole package is assumed to be "on".
                 */
                if (state != NULL && *state != ACPI_STA_POW_ON)
                        break;
        }

out:
        if (buf.Pointer != NULL)
                AcpiOsFree(buf.Pointer);

        return rv;
}

static ACPI_STATUS
acpifan_get_status(ACPI_HANDLE hdl, int *state)
{
        ACPI_INTEGER buf;
        ACPI_STATUS rv;

        rv = acpi_eval_integer(hdl, "_STA", &buf);

        if (ACPI_FAILURE(rv))
                return rv;

        if (buf != ACPI_STA_POW_OFF && buf != ACPI_STA_POW_ON)
                return AE_BAD_DATA;

        if (state != NULL)
                *state = buf;

        return AE_OK;
}

static bool
acpifan_sysctl_init(device_t self)
{
        struct acpifan_softc *sc = device_private(self);
        const struct sysctlnode *cnode;
        const struct sysctlnode *rnode;
        const char *ptr;

        if ((ptr = strstr(device_xname(self), "fan")) == NULL)
                return false;

        if (sysctl_createv(&sc->sc_log, 0, NULL, NULL,
                CTLFLAG_PERMANENT, CTLTYPE_NODE, "hw",
                NULL, NULL, 0, NULL, 0, CTL_HW, CTL_EOL) != 0)
                return false;

        if (sysctl_createv(&sc->sc_log, 0, NULL, &rnode,
                CTLFLAG_PERMANENT, CTLTYPE_NODE, "acpi",
                NULL, NULL, 0, NULL, 0, CTL_HW, CTL_CREATE, CTL_EOL) != 0)
                return false;

        if (sysctl_createv(&sc->sc_log, 0, &rnode, &cnode,
                CTLFLAG_PERMANENT | CTLFLAG_READWRITE, CTLTYPE_INT, ptr,
                SYSCTL_DESCR("fan control"), acpifan_sysctl_helper,
                0, sc, 0, CTL_CREATE, CTL_EOL) != 0)
                return false;

        return true;
}

static int
acpifan_sysctl_helper(SYSCTLFN_ARGS)
{
        struct acpifan_softc *sc;
        struct sysctlnode node;
        int error, state, t;
        ACPI_STATUS rv;

        sc = rnode->sysctl_data;
        rv = acpifan_get_state(sc->sc_node->ad_handle, &t);

        if (ACPI_FAILURE(rv)) {
                aprint_error_dev(sc->sc_dev, "failed to get state: %s\n",
                    AcpiFormatException(rv));
                return EIO;
        }

        node = *rnode;
        node.sysctl_data = &t;

        error = sysctl_lookup(SYSCTLFN_CALL(&node));

        if (error || newp == NULL)
                return error;

        switch (t) {

        case ACPI_STA_POW_ON:
                state = ACPI_STATE_D0;
                break;

        case ACPI_STA_POW_OFF:
                state = ACPI_STATE_D3;
                break;

        default:
                return EINVAL;
        }

        rv = acpi_pwr_switch_consumer(sc->sc_node->ad_handle, state);

        if (ACPI_FAILURE(rv) && rv != AE_BAD_PARAMETER) {
                aprint_error_dev(sc->sc_dev, "failed to set state: %s\n",
                    AcpiFormatException(rv));
                return EIO;
        }

        return 0;
}