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fdt_gpio.c revision 1.3
      1 /* $NetBSD: fdt_gpio.c,v 1.2 2015/12/16 12:17:45 jmcneill Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2015 Jared D. McNeill <jmcneill (at) invisible.ca>
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: fdt_gpio.c,v 1.2 2015/12/16 12:17:45 jmcneill Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/bus.h>
     34 #include <sys/kmem.h>
     35 
     36 #include <libfdt.h>
     37 #include <dev/fdt/fdtvar.h>
     38 
     39 struct fdtbus_gpio_controller {
     40 	device_t gc_dev;
     41 	int gc_phandle;
     42 	const struct fdtbus_gpio_controller_func *gc_funcs;
     43 
     44 	struct fdtbus_gpio_controller *gc_next;
     45 };
     46 
     47 static struct fdtbus_gpio_controller *fdtbus_gc = NULL;
     48 
     49 int
     50 fdtbus_register_gpio_controller(device_t dev, int phandle,
     51     const struct fdtbus_gpio_controller_func *funcs)
     52 {
     53 	struct fdtbus_gpio_controller *gc;
     54 
     55 	gc = kmem_alloc(sizeof(*gc), KM_SLEEP);
     56 	gc->gc_dev = dev;
     57 	gc->gc_phandle = phandle;
     58 	gc->gc_funcs = funcs;
     59 
     60 	gc->gc_next = fdtbus_gc;
     61 	fdtbus_gc = gc;
     62 
     63 	return 0;
     64 }
     65 
     66 static struct fdtbus_gpio_controller *
     67 fdtbus_get_gpio_controller(int phandle)
     68 {
     69 	struct fdtbus_gpio_controller *gc;
     70 
     71 	for (gc = fdtbus_gc; gc; gc = gc->gc_next) {
     72 		if (gc->gc_phandle == phandle) {
     73 			return gc;
     74 		}
     75 	}
     76 
     77 	return NULL;
     78 }
     79 
     80 struct fdtbus_gpio_pin *
     81 fdtbus_gpio_acquire(int phandle, const char *prop, int flags)
     82 {
     83 	struct fdtbus_gpio_controller *gc;
     84 	struct fdtbus_gpio_pin *gp;
     85 	int gpio_phandle, len;
     86 	u_int *data;
     87 
     88 	gpio_phandle = fdtbus_get_phandle(phandle, prop);
     89 	if (gpio_phandle == -1) {
     90 		return NULL;
     91 	}
     92 
     93 	gc = fdtbus_get_gpio_controller(gpio_phandle);
     94 	if (gc == NULL) {
     95 		return NULL;
     96 	}
     97 
     98 	len = OF_getproplen(phandle, prop);
     99 	if (len < 4) {
    100 		return NULL;
    101 	}
    102 
    103 	data = kmem_alloc(len, KM_SLEEP);
    104 	if (OF_getprop(phandle, prop, data, len) != len) {
    105 		kmem_free(data, len);
    106 		return NULL;
    107 	}
    108 
    109 	gp = kmem_alloc(sizeof(*gp), KM_SLEEP);
    110 	gp->gp_gc = gc;
    111 	gp->gp_priv = gc->gc_funcs->acquire(gc->gc_dev, data, len, flags);
    112 	if (gp->gp_priv == NULL) {
    113 		kmem_free(data, len);
    114 		return NULL;
    115 	}
    116 
    117 	return gp;
    118 }
    119 
    120 void
    121 fdtbus_gpio_release(struct fdtbus_gpio_pin *gp)
    122 {
    123 	struct fdtbus_gpio_controller *gc = gp->gp_gc;
    124 
    125 	gc->gc_funcs->release(gc->gc_dev, gp->gp_priv);
    126 	kmem_free(gp, sizeof(*gp));
    127 }
    128 
    129 int
    130 fdtbus_gpio_read(struct fdtbus_gpio_pin *gp)
    131 {
    132 	struct fdtbus_gpio_controller *gc = gp->gp_gc;
    133 
    134 	return gc->gc_funcs->read(gc->gc_dev, gp->gp_priv, false);
    135 }
    136 
    137 void
    138 fdtbus_gpio_write(struct fdtbus_gpio_pin *gp, int val)
    139 {
    140 	struct fdtbus_gpio_controller *gc = gp->gp_gc;
    141 
    142 	gc->gc_funcs->write(gc->gc_dev, gp->gp_priv, val, false);
    143 }
    144 
    145 int
    146 fdtbus_gpio_read_raw(struct fdtbus_gpio_pin *gp)
    147 {
    148 	struct fdtbus_gpio_controller *gc = gp->gp_gc;
    149 
    150 	return gc->gc_funcs->read(gc->gc_dev, gp->gp_priv, true);
    151 }
    152 
    153 void
    154 fdtbus_gpio_write_raw(struct fdtbus_gpio_pin *gp, int val)
    155 {
    156 	struct fdtbus_gpio_controller *gc = gp->gp_gc;
    157 
    158 	gc->gc_funcs->write(gc->gc_dev, gp->gp_priv, val, true);
    159 }
    160