FreeBSD/Linux Kernel Cross Reference
sys/arm/ti/am335x/am335x_scm.c

     /*-
      * Copyright (c) 2016 Rubicon Communications, LLC (Netgate)
      * 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>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/bus.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/sysctl.h>
    
    #include <machine/bus.h>
    
    #include <arm/ti/am335x/am335x_scm.h>
    #include <arm/ti/ti_cpuid.h>
    #include <arm/ti/ti_scm.h>
    
    #include <dev/extres/syscon/syscon.h>
    #include "syscon_if.h"
    
    #define TZ_ZEROC        2731
    
    struct am335x_scm_softc {
            int                     sc_last_temp;
            struct sysctl_oid       *sc_temp_oid;
            struct syscon           *syscon;
    };
    
    static int
    am335x_scm_temp_sysctl(SYSCTL_HANDLER_ARGS)
    {
            device_t dev;
            int i, temp;
            struct am335x_scm_softc *sc;
            uint32_t reg;
    
            dev = (device_t)arg1;
            sc = device_get_softc(dev);
    
            /* Read the temperature and convert to Kelvin. */
            for(i = 50; i > 0; i--) {
                    reg = SYSCON_READ_4(sc->syscon, SCM_BGAP_CTRL);
                    if ((reg & SCM_BGAP_EOCZ) == 0)
                            break;
                    DELAY(50);
            }
            if ((reg & SCM_BGAP_EOCZ) == 0) {
                    sc->sc_last_temp =
                        (reg >> SCM_BGAP_TEMP_SHIFT) & SCM_BGAP_TEMP_MASK;
                    sc->sc_last_temp *= 10;
            }
            temp = sc->sc_last_temp + TZ_ZEROC;
    
            return (sysctl_handle_int(oidp, &temp, 0, req));
    }
    
    static void
    am335x_scm_identify(driver_t *driver, device_t parent)
    {
            device_t child;
    
            /* AM335x only. */
            if (ti_chip() != CHIP_AM335X)
                    return;
    
            /* Make sure we attach only once. */
            if (device_find_child(parent, "am335x_scm", -1) != NULL)
                    return;
    
            child = device_add_child(parent, "am335x_scm", -1);
            if (child == NULL)
                    device_printf(parent, "cannot add ti_scm child\n");
    }
    
   static int
   am335x_scm_probe(device_t dev)
   {
           /* Just allow the first one */
           if (strcmp(device_get_nameunit(dev), "am335x_scm0") != 0)
                   return (ENXIO);
   
           device_set_desc(dev, "AM335x Control Module Extension");
   
           return (BUS_PROBE_DEFAULT);
   }
   
   static int
   am335x_scm_attach(device_t dev)
   {
           struct am335x_scm_softc *sc;
           struct sysctl_ctx_list *ctx;
           struct sysctl_oid_list *tree;
           uint32_t reg;
           phandle_t opp_table;
           int err;
   
           sc = device_get_softc(dev);
   
           /* FIXME: For now; Go and kidnap syscon from opp-table */
           opp_table = OF_finddevice("/opp-table");
           if (opp_table == -1) {
                   device_printf(dev, "Cant find /opp-table\n");
                   return (ENXIO);
           }
           if (!OF_hasprop(opp_table, "syscon")) {
                   device_printf(dev, "/opp-table missing syscon property\n");
                   return (ENXIO);
           }
           err = syscon_get_by_ofw_property(dev, opp_table, "syscon", &sc->syscon);
           if (err) {
                   device_printf(dev, "Failed to get syscon\n");
                   return (ENXIO);
           }
   
           /* Reset the digital outputs. */
           SYSCON_WRITE_4(sc->syscon, SCM_BGAP_CTRL, 0);
           reg = SYSCON_READ_4(sc->syscon, SCM_BGAP_CTRL);
           DELAY(500);
           /* Set continuous mode. */
           SYSCON_WRITE_4(sc->syscon, SCM_BGAP_CTRL, SCM_BGAP_CONTCONV);
           reg = SYSCON_READ_4(sc->syscon, SCM_BGAP_CTRL);
           DELAY(500);
           /* Start the ADC conversion. */
           reg = SCM_BGAP_CLRZ | SCM_BGAP_CONTCONV | SCM_BGAP_SOC;
           SYSCON_WRITE_4(sc->syscon, SCM_BGAP_CTRL, reg);
   
           /* Temperature sysctl. */
           ctx = device_get_sysctl_ctx(dev);
           tree = SYSCTL_CHILDREN(device_get_sysctl_tree(dev));
           sc->sc_temp_oid = SYSCTL_ADD_PROC(ctx, tree, OID_AUTO,
               "temperature", CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
               dev, 0, am335x_scm_temp_sysctl, "IK", "Current temperature");
   
           return (0);
   }
   
   static int
   am335x_scm_detach(device_t dev)
   {
           struct am335x_scm_softc *sc;
   
           sc = device_get_softc(dev);
   
           /* Remove temperature sysctl. */
           if (sc->sc_temp_oid != NULL)
                   sysctl_remove_oid(sc->sc_temp_oid, 1, 0);
   
           /* Stop the bandgap ADC. */
           SYSCON_WRITE_4(sc->syscon, SCM_BGAP_CTRL, SCM_BGAP_BGOFF);
   
           return (0);
   }
   
   static device_method_t am335x_scm_methods[] = {
           DEVMETHOD(device_identify,      am335x_scm_identify),
           DEVMETHOD(device_probe,         am335x_scm_probe),
           DEVMETHOD(device_attach,        am335x_scm_attach),
           DEVMETHOD(device_detach,        am335x_scm_detach),
   
           DEVMETHOD_END
   };
   
   static driver_t am335x_scm_driver = {
           "am335x_scm",
           am335x_scm_methods,
           sizeof(struct am335x_scm_softc),
   };
   
   DRIVER_MODULE(am335x_scm, ti_scm, am335x_scm_driver, 0, 0);
   MODULE_VERSION(am335x_scm, 1);
   MODULE_DEPEND(am335x_scm, ti_scm_syscon, 1, 1, 1);

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