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videopll.c revision 1.1.6.2 
      1 /*	$NetBSD: videopll.c,v 1.1.6.2 2012/04/17 00:06:37 yamt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2012 Michael Lorenz
      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, BUT
     21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 /*
     29  * A driver for the iic-controlled PLLs used in early Apple onboard video
     30  * hardware. For now we support /valkyrie only but others use vary similar
     31  * schemes to program their pixel clock so adding support for those should
     32  * be simple enough.
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 __KERNEL_RCSID(0, "$NetBSD: videopll.c,v 1.1.6.2 2012/04/17 00:06:37 yamt Exp $");
     37 
     38 #include <sys/param.h>
     39 #include <sys/systm.h>
     40 #include <sys/kernel.h>
     41 #include <sys/device.h>
     42 #include <sys/malloc.h>
     43 
     44 #include <dev/ofw/openfirm.h>
     45 #include <dev/i2c/i2cvar.h>
     46 #include <arch/macppc/dev/videopllvar.h>
     47 
     48 #include "opt_videopll.h"
     49 #ifdef VIDEOPLL_DEBUG
     50 #define DPRINTF printf
     51 #else
     52 #define DPRINTF while (0) printf
     53 #endif
     54 
     55 struct videopll_softc {
     56 	device_t sc_dev;
     57 	i2c_tag_t sc_tag;
     58 	int sc_addr;
     59 };
     60 
     61 static int  videopll_match(device_t, cfdata_t, void *);
     62 static void videopll_attach(device_t, device_t, void *);
     63 
     64 CFATTACH_DECL_NEW(videopll, sizeof(struct videopll_softc),
     65 	videopll_match, videopll_attach, NULL, NULL);
     66 
     67 static void *glob = NULL;
     68 
     69 static int
     70 videopll_match(device_t parent, cfdata_t cfdata, void *aux)
     71 {
     72 	struct i2c_attach_args *ia = aux;
     73 	int node;
     74 
     75 	/* we support only /valkyrie so far */
     76 	node = OF_finddevice("/valkyrie");
     77 	if (node == -1)
     78 		return 0;
     79 	/* make sure we only attach to cuda's iic bus */
     80 	if (!device_is_a(device_parent(parent), "cuda"))
     81 		return 0;
     82 	if (ia->ia_addr == 0x50)
     83 		return 100;
     84 	return 0;
     85 }
     86 
     87 static void
     88 videopll_attach(device_t parent, device_t self, void *aux)
     89 {
     90 	struct i2c_attach_args *ia = aux;
     91 	struct videopll_softc *sc = device_private(self);
     92 
     93 	sc->sc_dev = self;
     94 	sc->sc_tag = ia->ia_tag;
     95 	sc->sc_addr = ia->ia_addr;
     96 	aprint_normal(": Apple onboard video PLL\n");
     97 	glob = sc;
     98 }
     99 
    100 /*
    101  * pixel clock:
    102  * 3.9064MHz * 2^p2 * p1 / p0
    103  */
    104 int
    105 videopll_set_freq(int freq)
    106 {
    107 	struct videopll_softc *sc = glob;
    108 	int p0, p1, p2;
    109 	int freq_out, diff, diff_b = 100000000;
    110 	int b0 = 0, b1 = 0, b2 = 0, freq_b = 0;
    111 	uint8_t cmdbuf[4];
    112 
    113 	if (glob == NULL)
    114 		return EIO;
    115 	/*
    116 	 * XXX
    117 	 * The parameter ranges were taken from Linux' valkyriefb.c mode list.
    118 	 * We don't really know what exact parameters the PLL supports but
    119 	 * this should be enough for the modes we can actually support
    120 	 */
    121 	for (p2 = 2; p2 < 4; p2++) {
    122 		for (p1 = 27; p1 < 43; p1++) {
    123 			for (p0 = 11; p0 < 26; p0++) {
    124 				freq_out = (3906400 * (1 << p2) * p1) / (p0 * 1000);
    125 				diff = abs(freq - freq_out);
    126 				if (diff < diff_b) {
    127 					diff_b = diff;
    128 					b0 = p0;
    129 					b1 = p1;
    130 					b2 = p2;
    131 					freq_b = freq_out;
    132 				}
    133 			}
    134 		}
    135 	}
    136 	if (freq_b == 0)
    137 		return EINVAL;
    138 	DPRINTF("param: %d %d %d -> %d\n", b0, b1, b2, freq_b);
    139 	iic_acquire_bus(sc->sc_tag, 0);
    140 	cmdbuf[0] = 1;
    141 	cmdbuf[1] = b0;
    142 	iic_exec(sc->sc_tag, I2C_OP_WRITE,
    143 	    sc->sc_addr, cmdbuf, 2, NULL, 0, 0);
    144 	cmdbuf[0] = 2;
    145 	cmdbuf[1] = b1;
    146 	iic_exec(sc->sc_tag, I2C_OP_WRITE,
    147 	    sc->sc_addr, cmdbuf, 2, NULL, 0, 0);
    148 	cmdbuf[0] = 3;
    149 	cmdbuf[1] = b2;
    150 	iic_exec(sc->sc_tag, I2C_OP_WRITE,
    151 	    sc->sc_addr, cmdbuf, 2, NULL, 0, 0);
    152 	iic_release_bus(sc->sc_tag, 0);
    153 	return 0;
    154 }
    155 
    156 
    157 
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