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fdt_gpio.c revision 1.5 
      1 /* $NetBSD: fdt_gpio.c,v 1.5 2017/08/13 18:27:11 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 1.5 2017/08/13 18:27:11 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 	return fdtbus_gpio_acquire_index(phandle, prop, 0, flags);
     84 }
     85 
     86 struct fdtbus_gpio_pin *
     87 fdtbus_gpio_acquire_index(int phandle, const char *prop,
     88     int index, int flags)
     89 {
     90 	struct fdtbus_gpio_controller *gc;
     91 	struct fdtbus_gpio_pin *gp = NULL;
     92 	const uint32_t *gpios, *p;
     93 	u_int n, gpio_cells;
     94 	int len, resid;
     95 
     96 	gpios = fdtbus_get_prop(phandle, prop, &len);
     97 	if (gpios == NULL)
     98 		return NULL;
     99 
    100 	p = gpios;
    101 	for (n = 0, resid = len; resid > 0; n++) {
    102 		const int gc_phandle =
    103 		    fdtbus_get_phandle_from_native(be32toh(p[0]));
    104 		if (of_getprop_uint32(gc_phandle, "#gpio-cells", &gpio_cells))
    105 			break;
    106 		if (n == index) {
    107 			gc = fdtbus_get_gpio_controller(gc_phandle);
    108 			if (gc == NULL)
    109 				return NULL;
    110 			gp = kmem_alloc(sizeof(*gp), KM_SLEEP);
    111 			gp->gp_gc = gc;
    112 			gp->gp_priv = gc->gc_funcs->acquire(gc->gc_dev,
    113 			    &p[0], (gpio_cells + 1) * 4, flags);
    114 			if (gp->gp_priv == NULL) {
    115 				kmem_free(gp, sizeof(*gp));
    116 				return NULL;
    117 			}
    118 			break;
    119 		}
    120 		resid -= (gpio_cells + 1) * 4;
    121 		p += gpio_cells + 1;
    122 	}
    123 
    124 	return gp;
    125 }
    126 
    127 void
    128 fdtbus_gpio_release(struct fdtbus_gpio_pin *gp)
    129 {
    130 	struct fdtbus_gpio_controller *gc = gp->gp_gc;
    131 
    132 	gc->gc_funcs->release(gc->gc_dev, gp->gp_priv);
    133 	kmem_free(gp, sizeof(*gp));
    134 }
    135 
    136 int
    137 fdtbus_gpio_read(struct fdtbus_gpio_pin *gp)
    138 {
    139 	struct fdtbus_gpio_controller *gc = gp->gp_gc;
    140 
    141 	return gc->gc_funcs->read(gc->gc_dev, gp->gp_priv, false);
    142 }
    143 
    144 void
    145 fdtbus_gpio_write(struct fdtbus_gpio_pin *gp, int val)
    146 {
    147 	struct fdtbus_gpio_controller *gc = gp->gp_gc;
    148 
    149 	gc->gc_funcs->write(gc->gc_dev, gp->gp_priv, val, false);
    150 }
    151 
    152 int
    153 fdtbus_gpio_read_raw(struct fdtbus_gpio_pin *gp)
    154 {
    155 	struct fdtbus_gpio_controller *gc = gp->gp_gc;
    156 
    157 	return gc->gc_funcs->read(gc->gc_dev, gp->gp_priv, true);
    158 }
    159 
    160 void
    161 fdtbus_gpio_write_raw(struct fdtbus_gpio_pin *gp, int val)
    162 {
    163 	struct fdtbus_gpio_controller *gc = gp->gp_gc;
    164 
    165 	gc->gc_funcs->write(gc->gc_dev, gp->gp_priv, val, true);
    166 }
    167