text: /*-
   * Copyright (c) 2012 Justin Hibbits
   * 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 ``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 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: soc2013/dpl/head/sys/powerpc/powermac/nvbl.c 240701 2012-08-21 23:55:29Z jhibbits $");
  
  #include <sys/param.h>
  #include <sys/bus.h>
  #include <sys/systm.h>
  #include <sys/module.h>
  #include <sys/kernel.h>
  #include <sys/rman.h>
  #include <sys/sysctl.h>
  
  #include <machine/bus.h>
  
  #include <dev/ofw/openfirm.h>
  
  #define NVIDIA_BRIGHT_MIN     (0x0ec)
  #define NVIDIA_BRIGHT_MAX     (0x538)
  #define NVIDIA_BRIGHT_SCALE   ((NVIDIA_BRIGHT_MAX - NVIDIA_BRIGHT_MIN)/100)
  /* nVidia's MMIO registers are at PCI BAR[0] */
  #define NVIDIA_MMIO_PMC       (0x0)
  #define  NVIDIA_PMC_OFF         (NVIDIA_MMIO_PMC + 0x10f0)
  #define   NVIDIA_PMC_BL_SHIFT    (16)
  #define   NVIDIA_PMC_BL_EN       (1 << 31)
  
  
  struct nvbl_softc {
  	device_t	 dev;
  	struct resource *sc_memr;
  };
  
  static void nvbl_identify(driver_t *driver, device_t parent);
  static int nvbl_probe(device_t dev);
  static int nvbl_attach(device_t dev);
  static int nvbl_setlevel(struct nvbl_softc *sc, int newlevel);
  static int nvbl_getlevel(struct nvbl_softc *sc);
  static int nvbl_sysctl(SYSCTL_HANDLER_ARGS);
  
  static device_method_t nvbl_methods[] = {
  	/* Device interface */
  	DEVMETHOD(device_identify, nvbl_identify),
  	DEVMETHOD(device_probe, nvbl_probe),
  	DEVMETHOD(device_attach, nvbl_attach),
  	{0, 0},
  };
  
  static driver_t	nvbl_driver = {
  	"backlight",
  	nvbl_methods,
  	sizeof(struct nvbl_softc)
  };
  
  static devclass_t nvbl_devclass;
  
  DRIVER_MODULE(nvbl, vgapci, nvbl_driver, nvbl_devclass, 0, 0);
  
  static void
  nvbl_identify(driver_t *driver, device_t parent)
  {
  	if (device_find_child(parent, "backlight", -1) == NULL)
  		device_add_child(parent, "backlight", -1);
  }
  
  static int
  nvbl_probe(device_t dev)
  {
  	char		control[8];
  	phandle_t	handle;
  
  	handle = OF_finddevice("mac-io/backlight");
  
  	if (handle == -1)
  		return (ENXIO);
  
  	if (OF_getprop(handle, "backlight-control", &control, sizeof(control)) < 0)
  		return (ENXIO);
  
  	if (strcmp(control, "mnca") != 0)
  		return (ENXIO);
  
  	device_set_desc(dev, "PowerBook backlight for nVidia graphics");
  
  	return (0);
  }
  
  static int
  nvbl_attach(device_t dev)
  {
  	struct nvbl_softc	*sc;
  	struct sysctl_ctx_list *ctx;
  	struct sysctl_oid *tree;
  	int			 rid;
  
  	sc = device_get_softc(dev);
  
  	rid = 0x10;	/* BAR[0], for the MMIO register */
  	sc->sc_memr = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
  			RF_ACTIVE | RF_SHAREABLE);
  	if (sc->sc_memr == NULL) {
  		device_printf(dev, "Could not alloc mem resource!\n");
  		return (ENXIO);
  	}
  
  	/* Turn on big-endian mode */
  	if (!(bus_read_stream_4(sc->sc_memr, NVIDIA_MMIO_PMC + 4) & 0x01000001)) {
  		bus_write_stream_4(sc->sc_memr, NVIDIA_MMIO_PMC + 4, 0x01000001);
  		mb();
  	}
  
  	ctx = device_get_sysctl_ctx(dev);
  	tree = device_get_sysctl_tree(dev);
  
  	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  			"level", CTLTYPE_INT | CTLFLAG_RW, sc, 0,
  			nvbl_sysctl, "I", "Backlight level (0-100)");
  
  	return (0);
  }
  
  static int
  nvbl_setlevel(struct nvbl_softc *sc, int newlevel)
  {
  	uint32_t pmc_reg;
  
  	if (newlevel > 100)
  		newlevel = 100;
  
  	if (newlevel < 0)
  		newlevel = 0;
  
  	if (newlevel > 0)
  		newlevel = (newlevel * NVIDIA_BRIGHT_SCALE) + NVIDIA_BRIGHT_MIN;
  
  	pmc_reg = bus_read_stream_4(sc->sc_memr, NVIDIA_PMC_OFF) & 0xffff;
  	pmc_reg |= NVIDIA_PMC_BL_EN | (newlevel << NVIDIA_PMC_BL_SHIFT);
  	bus_write_stream_4(sc->sc_memr, NVIDIA_PMC_OFF, pmc_reg);
  
  	return (0);
  }
  
  static int
  nvbl_getlevel(struct nvbl_softc *sc)
  {
  	uint16_t level;
  
  	level = bus_read_stream_2(sc->sc_memr, NVIDIA_PMC_OFF) & 0x7fff;
  
  	if (level  < NVIDIA_BRIGHT_MIN)
  		return 0;
  
  	level = (level - NVIDIA_BRIGHT_MIN) / NVIDIA_BRIGHT_SCALE;
  
  	return (level);
  }
  
  static int
  nvbl_sysctl(SYSCTL_HANDLER_ARGS)
  {
  	struct nvbl_softc *sc;
  	int newlevel, error;
  
  	sc = arg1;
  
  	newlevel = nvbl_getlevel(sc);
  
  	error = sysctl_handle_int(oidp, &newlevel, 0, req);
  
  	if (error || !req->newptr)
  		return (error);
  
  	return (nvbl_setlevel(sc, newlevel));
  }
  