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fdt_pwm.c revision 1.1.2.2 
      1 /* $NetBSD: fdt_pwm.c,v 1.1.2.2 2018/05/21 04:36:05 pgoyette Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2018 Jared 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_pwm.c,v 1.1.2.2 2018/05/21 04:36:05 pgoyette 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_pwm_controller {
     40 	device_t pc_dev;
     41 	int pc_phandle;
     42 	const struct fdtbus_pwm_controller_func *pc_funcs;
     43 
     44 	struct fdtbus_pwm_controller *pc_next;
     45 };
     46 
     47 static struct fdtbus_pwm_controller *fdtbus_pc = NULL;
     48 
     49 int
     50 fdtbus_register_pwm_controller(device_t dev, int phandle,
     51     const struct fdtbus_pwm_controller_func *funcs)
     52 {
     53 	struct fdtbus_pwm_controller *pc;
     54 
     55 	pc = kmem_alloc(sizeof(*pc), KM_SLEEP);
     56 	pc->pc_dev = dev;
     57 	pc->pc_phandle = phandle;
     58 	pc->pc_funcs = funcs;
     59 
     60 	pc->pc_next = fdtbus_pc;
     61 	fdtbus_pc = pc;
     62 
     63 	return 0;
     64 }
     65 
     66 static struct fdtbus_pwm_controller *
     67 fdtbus_get_pwm_controller(int phandle)
     68 {
     69 	struct fdtbus_pwm_controller *pc;
     70 
     71 	for (pc = fdtbus_pc; pc; pc = pc->pc_next) {
     72 		if (pc->pc_phandle == phandle) {
     73 			return pc;
     74 		}
     75 	}
     76 
     77 	return NULL;
     78 }
     79 
     80 pwm_tag_t
     81 fdtbus_pwm_acquire(int phandle, const char *prop)
     82 {
     83 	return fdtbus_pwm_acquire_index(phandle, prop, 0);
     84 }
     85 
     86 pwm_tag_t
     87 fdtbus_pwm_acquire_index(int phandle, const char *prop, int index)
     88 {
     89 	struct fdtbus_pwm_controller *pc;
     90 	const uint32_t *pwms, *p;
     91 	u_int n, pwm_cells;
     92 	int len, resid;
     93 
     94 	pwms = fdtbus_get_prop(phandle, prop, &len);
     95 	if (pwms == NULL)
     96 		return NULL;
     97 
     98 	p = pwms;
     99 	for (n = 0, resid = len; resid > 0; n++) {
    100 		const int pc_phandle =
    101 		    fdtbus_get_phandle_from_native(be32toh(p[0]));
    102 		if (of_getprop_uint32(pc_phandle, "#pwm-cells", &pwm_cells))
    103 			break;
    104 		if (n == index) {
    105 			pc = fdtbus_get_pwm_controller(pc_phandle);
    106 			if (pc == NULL)
    107 				return NULL;
    108 			return pc->pc_funcs->get_tag(pc->pc_dev,
    109 			    &p[0], (pwm_cells + 1) * 4);
    110 		}
    111 		resid -= (pwm_cells + 1) * 4;
    112 		p += pwm_cells + 1;
    113 	}
    114 
    115 	return NULL;
    116 }
    117