Add GPIO backlight driver compatible with Linux FDT bindings.

Brightness is controlled through sysctl dev.gpiobacklight.X.brightness:
  - any value greater than 0: backlight is on
  - any value less than or equal to  0: backlight is off

FDT bindings docs in Linux tree:
    Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt

diff --git a/sys/conf/files b/sys/conf/files
index 99cef6dab2c2d3bb978b5c59083d5f767fcd50f0..d1060bc0175000cc5c9a56054da409e49acc3dda 100644 (file)
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -1436,6 +1436,7 @@ dev/fxp/inphy.c                   optional fxp
 dev/gem/if_gem.c               optional gem
 dev/gem/if_gem_pci.c           optional gem pci
 dev/gem/if_gem_sbus.c          optional gem sbus
+dev/gpio/gpiobacklight.c       optional gpiobacklight fdt
 dev/gpio/gpiobus.c             optional gpio                           \
        dependency      "gpiobus_if.h"
 dev/gpio/gpioc.c               optional gpio                           \

diff --git a/sys/dev/gpio/gpiobacklight.c b/sys/dev/gpio/gpiobacklight.c
new file mode 100644 (file)
index 0000000..3ff74f1
--- /dev/null
+++ b/sys/dev/gpio/gpiobacklight.c
@@ -0,0 +1,211 @@
+/*-
+ * Copyright (c) 2015 Oleksandr Tymoshenko <gonzo@freebsd.org>
+ * 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 "opt_platform.h"
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/gpio.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/malloc.h>
+#include <sys/module.h>
+#include <sys/mutex.h>
+#include <sys/sysctl.h>
+
+#include <dev/fdt/fdt_common.h>
+#include <dev/ofw/ofw_bus.h>
+
+#include <dev/gpio/gpiobusvar.h>
+
+#include "gpiobus_if.h"
+
+/*
+ * Only one pin for led
+ */
+#define        GPIOBL_PIN      0
+
+#define GPIOBL_LOCK(_sc)               mtx_lock(&(_sc)->sc_mtx)
+#define        GPIOBL_UNLOCK(_sc)              mtx_unlock(&(_sc)->sc_mtx)
+#define GPIOBL_LOCK_INIT(_sc) \
+       mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->sc_dev), \
+           "gpiobacklight", MTX_DEF)
+#define GPIOBL_LOCK_DESTROY(_sc)       mtx_destroy(&_sc->sc_mtx);
+
+struct gpiobacklight_softc 
+{
+       device_t        sc_dev;
+       device_t        sc_busdev;
+       struct mtx      sc_mtx;
+
+       struct sysctl_oid       *sc_oid;
+       int             sc_brightness;
+};
+
+static int gpiobacklight_sysctl(SYSCTL_HANDLER_ARGS);
+static void gpiobacklight_update_brightness(struct gpiobacklight_softc *);
+static int gpiobacklight_probe(device_t);
+static int gpiobacklight_attach(device_t);
+static int gpiobacklight_detach(device_t);
+
+static void 
+gpiobacklight_update_brightness(struct gpiobacklight_softc *sc)
+{
+       int error;
+
+       GPIOBL_LOCK(sc);
+       error = GPIOBUS_ACQUIRE_BUS(sc->sc_busdev, sc->sc_dev,
+           GPIOBUS_DONTWAIT);
+       if (error != 0) {
+               GPIOBL_UNLOCK(sc);
+               return;
+       }
+       error = GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev,
+           GPIOBL_PIN, GPIO_PIN_OUTPUT);
+       if (error == 0)
+               GPIOBUS_PIN_SET(sc->sc_busdev, sc->sc_dev, GPIOBL_PIN,
+                   sc->sc_brightness ? GPIO_PIN_HIGH : GPIO_PIN_LOW);
+       GPIOBUS_RELEASE_BUS(sc->sc_busdev, sc->sc_dev);
+       GPIOBL_UNLOCK(sc);
+}
+
+static int
+gpiobacklight_sysctl(SYSCTL_HANDLER_ARGS)
+{
+       struct gpiobacklight_softc *sc;
+       int error;
+       int brightness;
+
+       sc = (struct gpiobacklight_softc*)arg1;
+       brightness = sc->sc_brightness;
+       error = sysctl_handle_int(oidp, &brightness, 0, req);
+
+       if (error != 0 || req->newptr == NULL)
+               return (error);
+
+       if (brightness <= 0)
+               sc->sc_brightness = 0;
+       else
+               sc->sc_brightness = 1;
+
+       gpiobacklight_update_brightness(sc);
+
+       return (error);
+}
+
+static void
+gpiobacklight_identify(driver_t *driver, device_t bus)
+{
+       phandle_t node, root;
+
+       root = OF_finddevice("/");
+       if (root == 0)
+               return;
+       for (node = OF_child(root); node != 0; node = OF_peer(node)) {
+               if (!fdt_is_compatible_strict(node, "gpio-backlight"))
+                       continue;
+               ofw_gpiobus_add_fdt_child(bus, driver->name, node);
+       }
+}
+
+static int
+gpiobacklight_probe(device_t dev)
+{
+
+       if (!ofw_bus_is_compatible(dev, "gpio-backlight"))
+               return (ENXIO);
+
+       device_set_desc(dev, "GPIO backlight");
+
+       return (0);
+}
+
+static int
+gpiobacklight_attach(device_t dev)
+{
+       struct gpiobacklight_softc *sc;
+       struct sysctl_ctx_list *ctx;
+       struct sysctl_oid *tree;
+       phandle_t node;
+
+       sc = device_get_softc(dev);
+       sc->sc_dev = dev;
+       sc->sc_busdev = device_get_parent(dev);
+
+       if ((node = ofw_bus_get_node(dev)) == -1)
+               return (ENXIO);
+
+       GPIOBL_LOCK_INIT(sc);
+       if (OF_hasprop(node, "default-on"))
+               sc->sc_brightness = 1;
+       else
+               sc->sc_brightness = 0;
+
+       /* Init backlight interface */
+       ctx = device_get_sysctl_ctx(sc->sc_dev);
+       tree = device_get_sysctl_tree(sc->sc_dev);
+       sc->sc_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
+           "brightness", CTLTYPE_INT | CTLFLAG_RW, sc, 0,
+           gpiobacklight_sysctl, "I", "backlight brightness");
+
+       gpiobacklight_update_brightness(sc);
+
+       return (0);
+}
+
+static int
+gpiobacklight_detach(device_t dev)
+{
+       struct gpiobacklight_softc *sc;
+
+       sc = device_get_softc(dev);
+       GPIOBL_LOCK_DESTROY(sc);
+       return (0);
+}
+
+static devclass_t gpiobacklight_devclass;
+
+static device_method_t gpiobacklight_methods[] = {
+       /* Device interface */
+       DEVMETHOD(device_identify,      gpiobacklight_identify),
+       DEVMETHOD(device_probe,         gpiobacklight_probe),
+       DEVMETHOD(device_attach,        gpiobacklight_attach),
+       DEVMETHOD(device_detach,        gpiobacklight_detach),
+
+       DEVMETHOD_END
+};
+
+static driver_t gpiobacklight_driver = {
+       "gpiobacklight",
+       gpiobacklight_methods,
+       sizeof(struct gpiobacklight_softc),
+};
+
+DRIVER_MODULE(gpiobacklight, gpiobus, gpiobacklight_driver, gpiobacklight_devclass, 0, 0);