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videopll.c revision 1.3.28.1 
      1 /*	$NetBSD: videopll.c,v 1.3.28.1 2021/08/09 00:30:08 thorpej 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 very 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 1.3.28.1 2021/08/09 00:30:08 thorpej 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 const struct device_compatible_entry compat_data[] = {
     70 	/* XXX a real "compatible" string would be nice... */
     71 	{ .compat = "aapl,valkyrie-videopll" },
     72 	DEVICE_COMPAT_EOL
     73 };
     74 
     75 static int
     76 videopll_match(device_t parent, cfdata_t cfdata, void *aux)
     77 {
     78 	struct i2c_attach_args *ia = aux;
     79 	int match_result;
     80 
     81 	if (iic_use_direct_match(ia, cfdata, compat_data, &match_result))
     82 		return match_result;
     83 
     84 	/* This driver is direct-config only. */
     85 
     86 	return 0;
     87 }
     88 
     89 static void
     90 videopll_attach(device_t parent, device_t self, void *aux)
     91 {
     92 	struct i2c_attach_args *ia = aux;
     93 	struct videopll_softc *sc = device_private(self);
     94 
     95 	sc->sc_dev = self;
     96 	sc->sc_tag = ia->ia_tag;
     97 	sc->sc_addr = ia->ia_addr;
     98 	aprint_normal(": Apple onboard video PLL\n");
     99 	glob = sc;
    100 }
    101 
    102 /*
    103  * pixel clock:
    104  * 3.9064MHz * 2^p2 * p1 / p0
    105  */
    106 int
    107 videopll_set_freq(int freq)
    108 {
    109 	struct videopll_softc *sc = glob;
    110 	int p0, p1, p2;
    111 	int freq_out, diff, diff_b = 100000000;
    112 	int b0 = 0, b1 = 0, b2 = 0, freq_b = 0;
    113 	uint8_t cmdbuf[4];
    114 
    115 	if (glob == NULL)
    116 		return EIO;
    117 	/*
    118 	 * XXX
    119 	 * The parameter ranges were taken from Linux' valkyriefb.c mode list.
    120 	 * We don't really know what exact parameters the PLL supports but
    121 	 * this should be enough for the modes we can actually support
    122 	 */
    123 	for (p2 = 2; p2 < 4; p2++) {
    124 		for (p1 = 27; p1 < 43; p1++) {
    125 			for (p0 = 11; p0 < 26; p0++) {
    126 				freq_out = (3906400 * (1 << p2) * p1) / (p0 * 1000);
    127 				diff = abs(freq - freq_out);
    128 				if (diff < diff_b) {
    129 					diff_b = diff;
    130 					b0 = p0;
    131 					b1 = p1;
    132 					b2 = p2;
    133 					freq_b = freq_out;
    134 				}
    135 			}
    136 		}
    137 	}
    138 	if (freq_b == 0)
    139 		return EINVAL;
    140 	DPRINTF("param: %d %d %d -> %d\n", b0, b1, b2, freq_b);
    141 	iic_acquire_bus(sc->sc_tag, 0);
    142 	cmdbuf[0] = 1;
    143 	cmdbuf[1] = b0;
    144 	iic_exec(sc->sc_tag, I2C_OP_WRITE,
    145 	    sc->sc_addr, cmdbuf, 2, NULL, 0, 0);
    146 	cmdbuf[0] = 2;
    147 	cmdbuf[1] = b1;
    148 	iic_exec(sc->sc_tag, I2C_OP_WRITE,
    149 	    sc->sc_addr, cmdbuf, 2, NULL, 0, 0);
    150 	cmdbuf[0] = 3;
    151 	cmdbuf[1] = b2;
    152 	iic_exec(sc->sc_tag, I2C_OP_WRITE,
    153 	    sc->sc_addr, cmdbuf, 2, NULL, 0, 0);
    154 	iic_release_bus(sc->sc_tag, 0);
    155 	return 0;
    156 }
    157 
    158 
    159 
    160