1/*	$NetBSD: nslu2_iic.c,v 1.12 2021/08/07 16:18:50 thorpej Exp $	*/
2
3/*-
4 * Copyright (c) 2006 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Steve C. Woodford.
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/param.h>
33#include <sys/systm.h>
34#include <sys/kernel.h>
35#include <sys/device.h>
36#include <sys/mutex.h>
37#include <sys/bus.h>
38
39#include <dev/i2c/i2cvar.h>
40#include <dev/i2c/i2c_bitbang.h>
41
42#include <arm/xscale/ixp425reg.h>
43#include <arm/xscale/ixp425var.h>
44
45#include <evbarm/nslu2/nslu2reg.h>
46
47struct slugiic_softc {
48	struct i2c_controller sc_ic;
49	struct i2c_bitbang_ops sc_ibo;
50	uint32_t sc_dirout;
51};
52
53static int
54slugiic_send_start(void *arg, int flags)
55{
56	struct slugiic_softc *sc = arg;
57
58	return (i2c_bitbang_send_start(sc, flags, &sc->sc_ibo));
59}
60
61static int
62slugiic_send_stop(void *arg, int flags)
63{
64	struct slugiic_softc *sc = arg;
65
66	return (i2c_bitbang_send_stop(sc, flags, &sc->sc_ibo));
67}
68
69static int
70slugiic_initiate_xfer(void *arg, i2c_addr_t addr, int flags)
71{
72	struct slugiic_softc *sc = arg;
73
74	return (i2c_bitbang_initiate_xfer(sc, addr, flags, &sc->sc_ibo));
75}
76
77static int
78slugiic_read_byte(void *arg, uint8_t *vp, int flags)
79{
80	struct slugiic_softc *sc = arg;
81
82	return (i2c_bitbang_read_byte(sc, vp, flags, &sc->sc_ibo));
83}
84
85static int
86slugiic_write_byte(void *arg, uint8_t v, int flags)
87{
88	struct slugiic_softc *sc = arg;
89
90	return (i2c_bitbang_write_byte(sc, v, flags, &sc->sc_ibo));
91}
92
93static void
94slugiic_set_dir(void *arg, uint32_t bits)
95{
96	struct slugiic_softc *sc = arg;
97	uint32_t reg;
98	int s;
99
100	if (sc->sc_dirout == bits)
101		return;
102
103	s = splhigh();
104
105	sc->sc_dirout = bits;
106
107	if (sc->sc_dirout) {
108		/* SDA is output; enable SDA output if SDA OUTR is low */
109		reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR);
110		if ((reg & GPIO_I2C_SDA_BIT) == 0) {
111			reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
112			reg &= ~GPIO_I2C_SDA_BIT;
113			GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg);
114		}
115	} else {
116		/* SDA is input; disable SDA output */
117		reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
118		reg |= GPIO_I2C_SDA_BIT;
119		GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg);
120	}
121
122	splx(s);
123}
124
125static void
126slugiic_set_bits(void *arg, uint32_t bits)
127{
128	struct slugiic_softc *sc = arg;
129	uint32_t oer, outr;
130	int s;
131
132	s = splhigh();
133
134	/*
135	 * Enable SCL output if the SCL line is to be driven low.
136	 * Enable SDA output if the SDA line is to be driven low and
137	 * SDA direction is output.
138	 * Otherwise switch them to input even if directions are output
139	 * so that we can emulate open collector output with the pullup
140	 * resistors.
141	 * If lines are to be set to high, disable OER first then set OUTR.
142	 * If lines are to be set to low, set OUTR first then enable OER.
143	 */
144	oer = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
145	if ((bits & GPIO_I2C_SCL_BIT) != 0)
146		oer |= GPIO_I2C_SCL_BIT;
147	if ((bits & GPIO_I2C_SDA_BIT) != 0)
148		oer |= GPIO_I2C_SDA_BIT;
149	GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer);
150
151	outr = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR);
152	outr &= ~(GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT);
153	GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, outr | bits);
154
155	if ((bits & GPIO_I2C_SCL_BIT) == 0)
156		oer &= ~GPIO_I2C_SCL_BIT;
157	if ((bits & GPIO_I2C_SDA_BIT) == 0 && sc->sc_dirout)
158		oer &= ~GPIO_I2C_SDA_BIT;
159	GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer);
160
161	splx(s);
162}
163
164static uint32_t
165slugiic_read_bits(void *arg)
166{
167	uint32_t reg;
168
169	reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPINR);
170	return (reg & (GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT));
171}
172
173static void
174slugiic_deferred_attach(device_t self)
175{
176	struct slugiic_softc *sc = device_private(self);
177	struct i2cbus_attach_args iba;
178	uint32_t reg;
179
180	reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR);
181	reg |= GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT;
182	GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, reg);
183
184	reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
185	reg &= ~GPIO_I2C_SCL_BIT;
186	reg |= GPIO_I2C_SDA_BIT;
187	GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg);
188
189	memset(&iba, 0, sizeof(iba));
190	iba.iba_tag = &sc->sc_ic;
191	config_found(self, &iba, iicbus_print, CFARGS_NONE);
192}
193
194static int
195slugiic_match(device_t parent, cfdata_t cf, void *aux)
196{
197
198	return (1);
199}
200
201static void
202slugiic_attach(device_t parent, device_t self, void *aux)
203{
204	struct slugiic_softc *sc = device_private(self);
205
206	aprint_naive("\n");
207	aprint_normal(": I2C bus\n");
208
209	iic_tag_init(&sc->sc_ic);
210	sc->sc_ic.ic_cookie = sc;
211	sc->sc_ic.ic_send_start = slugiic_send_start;
212	sc->sc_ic.ic_send_stop = slugiic_send_stop;
213	sc->sc_ic.ic_initiate_xfer = slugiic_initiate_xfer;
214	sc->sc_ic.ic_read_byte = slugiic_read_byte;
215	sc->sc_ic.ic_write_byte = slugiic_write_byte;
216
217	sc->sc_ibo.ibo_set_dir = slugiic_set_dir;
218	sc->sc_ibo.ibo_set_bits = slugiic_set_bits;
219	sc->sc_ibo.ibo_read_bits = slugiic_read_bits;
220	sc->sc_ibo.ibo_bits[I2C_BIT_SDA] = GPIO_I2C_SDA_BIT;
221	sc->sc_ibo.ibo_bits[I2C_BIT_SCL] = GPIO_I2C_SCL_BIT;
222	sc->sc_ibo.ibo_bits[I2C_BIT_OUTPUT] = 1;
223	sc->sc_ibo.ibo_bits[I2C_BIT_INPUT] = 0;
224
225	sc->sc_dirout = 0;
226
227	/*
228	 * Defer until ixp425_softc has been initialised
229	 */
230	config_interrupts(self, slugiic_deferred_attach);
231}
232
233CFATTACH_DECL_NEW(slugiic, sizeof(struct slugiic_softc),
234    slugiic_match, slugiic_attach, NULL, NULL);
235