1/*	$NetBSD: videopll.c,v 1.4 2023/12/20 15:29:04 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 1.4 2023/12/20 15:29:04 thorpej Exp $");
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/kernel.h>
41#include <sys/device.h>
42
43#include <dev/ofw/openfirm.h>
44#include <dev/i2c/i2cvar.h>
45#include <arch/macppc/dev/videopllvar.h>
46
47#include "opt_videopll.h"
48#ifdef VIDEOPLL_DEBUG
49#define DPRINTF printf
50#else
51#define DPRINTF while (0) printf
52#endif
53
54struct videopll_softc {
55	device_t sc_dev;
56	i2c_tag_t sc_tag;
57	int sc_addr;
58};
59
60static int  videopll_match(device_t, cfdata_t, void *);
61static void videopll_attach(device_t, device_t, void *);
62
63CFATTACH_DECL_NEW(videopll, sizeof(struct videopll_softc),
64	videopll_match, videopll_attach, NULL, NULL);
65
66static void *glob = NULL;
67
68static int
69videopll_match(device_t parent, cfdata_t cfdata, void *aux)
70{
71	struct i2c_attach_args *ia = aux;
72	int match_result;
73
74	if (iic_use_direct_match(ia, cfdata, NULL, &match_result))
75		return match_result;
76
77	/* This driver is direct-config only. */
78
79	return 0;
80}
81
82static void
83videopll_attach(device_t parent, device_t self, void *aux)
84{
85	struct i2c_attach_args *ia = aux;
86	struct videopll_softc *sc = device_private(self);
87
88	sc->sc_dev = self;
89	sc->sc_tag = ia->ia_tag;
90	sc->sc_addr = ia->ia_addr;
91	aprint_normal(": Apple onboard video PLL\n");
92	glob = sc;
93}
94
95/*
96 * pixel clock:
97 * 3.9064MHz * 2^p2 * p1 / p0
98 */
99int
100videopll_set_freq(int freq)
101{
102	struct videopll_softc *sc = glob;
103	int p0, p1, p2;
104	int freq_out, diff, diff_b = 100000000;
105	int b0 = 0, b1 = 0, b2 = 0, freq_b = 0;
106	uint8_t cmdbuf[4];
107
108	if (glob == NULL)
109		return EIO;
110	/*
111	 * XXX
112	 * The parameter ranges were taken from Linux' valkyriefb.c mode list.
113	 * We don't really know what exact parameters the PLL supports but
114	 * this should be enough for the modes we can actually support
115	 */
116	for (p2 = 2; p2 < 4; p2++) {
117		for (p1 = 27; p1 < 43; p1++) {
118			for (p0 = 11; p0 < 26; p0++) {
119				freq_out = (3906400 * (1 << p2) * p1) / (p0 * 1000);
120				diff = abs(freq - freq_out);
121				if (diff < diff_b) {
122					diff_b = diff;
123					b0 = p0;
124					b1 = p1;
125					b2 = p2;
126					freq_b = freq_out;
127				}
128			}
129		}
130	}
131	if (freq_b == 0)
132		return EINVAL;
133	DPRINTF("param: %d %d %d -> %d\n", b0, b1, b2, freq_b);
134	iic_acquire_bus(sc->sc_tag, 0);
135	cmdbuf[0] = 1;
136	cmdbuf[1] = b0;
137	iic_exec(sc->sc_tag, I2C_OP_WRITE,
138	    sc->sc_addr, cmdbuf, 2, NULL, 0, 0);
139	cmdbuf[0] = 2;
140	cmdbuf[1] = b1;
141	iic_exec(sc->sc_tag, I2C_OP_WRITE,
142	    sc->sc_addr, cmdbuf, 2, NULL, 0, 0);
143	cmdbuf[0] = 3;
144	cmdbuf[1] = b2;
145	iic_exec(sc->sc_tag, I2C_OP_WRITE,
146	    sc->sc_addr, cmdbuf, 2, NULL, 0, 0);
147	iic_release_bus(sc->sc_tag, 0);
148	return 0;
149}
150
151
152
153