1/*	$NetBSD: tsciic.c,v 1.4 2021/08/07 16:18:41 thorpej Exp $	*/
2
3/*
4 * Copyright (c) 2013 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Julian Coleman.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33
34__KERNEL_RCSID(0, "$NetBSD: tsciic.c,v 1.4 2021/08/07 16:18:41 thorpej Exp $");
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/device.h>
39
40#include <alpha/pci/tsreg.h>
41#include <alpha/pci/tsvar.h>
42
43#include <dev/i2c/i2cvar.h>
44#include <dev/i2c/i2c_bitbang.h>
45#include <dev/i2c/ddcvar.h>
46
47/* I2C glue */
48static int tsciic_send_start(void *, int);
49static int tsciic_send_stop(void *, int);
50static int tsciic_initiate_xfer(void *, i2c_addr_t, int);
51static int tsciic_read_byte(void *, uint8_t *, int);
52static int tsciic_write_byte(void *, uint8_t, int);
53
54/* I2C bitbang glue */
55static void tsciicbb_set_bits(void *, uint32_t);
56static void tsciicbb_set_dir(void *, uint32_t);
57static uint32_t tsciicbb_read(void *);
58
59#define MPD_BIT_SDA 0x01
60#define MPD_BIT_SCL 0x02
61static const struct i2c_bitbang_ops tsciicbb_ops = {
62	tsciicbb_set_bits,
63	tsciicbb_set_dir,
64	tsciicbb_read,
65	{
66		MPD_BIT_SDA,
67		MPD_BIT_SCL,
68		0,
69		0
70	}
71};
72
73void
74tsciic_init(device_t self)
75{
76	struct tsciic_softc *sc = device_private(self);
77	struct i2cbus_attach_args iba;
78
79	iic_tag_init(&sc->sc_i2c);
80	sc->sc_i2c.ic_cookie = sc;
81	sc->sc_i2c.ic_send_start = tsciic_send_start;
82	sc->sc_i2c.ic_send_stop = tsciic_send_stop;
83	sc->sc_i2c.ic_initiate_xfer = tsciic_initiate_xfer;
84	sc->sc_i2c.ic_read_byte = tsciic_read_byte;
85	sc->sc_i2c.ic_write_byte = tsciic_write_byte;
86
87	memset(&iba, 0, sizeof(iba));
88	iba.iba_tag = &sc->sc_i2c;
89
90	config_found(self, &iba, iicbus_print, CFARGS_NONE);
91}
92
93/* I2C bitbanging */
94static void
95tsciicbb_set_bits(void *cookie, uint32_t bits)
96{
97	uint64_t val;
98
99	val = (bits & MPD_BIT_SDA ? MPD_DS : 0) |
100	    (bits & MPD_BIT_SCL ? MPD_CKS : 0);
101	alpha_mb();
102	STQP(TS_C_MPD) = val;
103	alpha_mb();
104}
105
106static void
107tsciicbb_set_dir(void *cookie, uint32_t dir)
108{
109	/* Nothing to do */
110}
111
112static uint32_t
113tsciicbb_read(void *cookie)
114{
115	uint64_t val;
116	uint32_t bits;
117
118	val = LDQP(TS_C_MPD);
119	bits = (val & MPD_DR ? MPD_BIT_SDA : 0) |
120	    (val & MPD_CKR ? MPD_BIT_SCL : 0);
121	return bits;
122}
123
124/* higher level I2C stuff */
125static int
126tsciic_send_start(void *cookie, int flags)
127{
128	return (i2c_bitbang_send_start(cookie, flags, &tsciicbb_ops));
129}
130
131static int
132tsciic_send_stop(void *cookie, int flags)
133{
134	return (i2c_bitbang_send_stop(cookie, flags, &tsciicbb_ops));
135}
136
137static int
138tsciic_initiate_xfer(void *cookie, i2c_addr_t addr, int flags)
139{
140	return (i2c_bitbang_initiate_xfer(cookie, addr, flags,
141	    &tsciicbb_ops));
142}
143
144static int
145tsciic_read_byte(void *cookie, uint8_t *valp, int flags)
146{
147	return (i2c_bitbang_read_byte(cookie, valp, flags, &tsciicbb_ops));
148}
149
150static int
151tsciic_write_byte(void *cookie, uint8_t val, int flags)
152{
153	return (i2c_bitbang_write_byte(cookie, val, flags, &tsciicbb_ops));
154}
155