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      1 /*	$NetBSD: gpiic_opb.c,v 1.13 2025/09/15 13:23:02 thorpej Exp $	*/
      2 
      3 /*
      4  * Copyright 2002, 2003 Wasabi Systems, Inc.
      5  * All rights reserved.
      6  *
      7  * Written by Steve C. Woodford for Wasabi Systems, Inc.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. All advertising materials mentioning features or use of this software
     18  *    must display the following acknowledgement:
     19  *      This product includes software developed for the NetBSD Project by
     20  *      Wasabi Systems, Inc.
     21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
     22  *    or promote products derived from this software without specific prior
     23  *    written permission.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
     26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
     29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     35  * POSSIBILITY OF SUCH DAMAGE.
     36  */
     37 
     38 #include "locators.h"
     39 
     40 #include <sys/param.h>
     41 #include <sys/systm.h>
     42 #include <sys/device.h>
     43 #include <sys/errno.h>
     44 #include <sys/mutex.h>
     45 #include <sys/cpu.h>
     46 
     47 #include <dev/i2c/i2cvar.h>
     48 #include <dev/i2c/i2c_bitbang.h>
     49 
     50 #include <powerpc/ibm4xx/cpu.h>
     51 #include <powerpc/ibm4xx/dev/opbvar.h>
     52 #include <powerpc/ibm4xx/dev/gpiicreg.h>
     53 
     54 struct gpiic_softc {
     55 	device_t sc_dev;
     56 	bus_space_tag_t sc_bust;
     57 	bus_space_handle_t sc_bush;
     58 	uint8_t sc_txen;
     59 	uint8_t sc_tx;
     60 	struct i2c_controller sc_i2c;
     61 	struct i2c_bitbang_ops sc_bops;
     62 };
     63 
     64 static int	gpiic_match(device_t, cfdata_t, void *);
     65 static void	gpiic_attach(device_t, device_t, void *);
     66 
     67 CFATTACH_DECL_NEW(gpiic, sizeof(struct gpiic_softc),
     68     gpiic_match, gpiic_attach, NULL, NULL);
     69 
     70 static int	gpiic_send_start(void *, int);
     71 static int	gpiic_send_stop(void *, int);
     72 static int	gpiic_initiate_xfer(void *, i2c_addr_t, int);
     73 static int	gpiic_read_byte(void *, uint8_t *, int);
     74 static int	gpiic_write_byte(void *, uint8_t, int);
     75 static void	gpiic_set_dir(void *, uint32_t);
     76 static void	gpiic_set_bits(void *, uint32_t);
     77 static uint32_t	gpiic_read_bits(void *);
     78 
     79 static int
     80 gpiic_match(device_t parent, cfdata_t cf, void *args)
     81 {
     82 	struct opb_attach_args * const oaa = args;
     83 
     84 	if (strcmp(oaa->opb_name, cf->cf_name) != 0)
     85 		return 0;
     86 
     87 	return (1);
     88 }
     89 
     90 static void
     91 gpiic_attach(device_t parent, device_t self, void *args)
     92 {
     93 	struct gpiic_softc * const sc = device_private(self);
     94 	struct opb_attach_args * const oaa = args;
     95 
     96 	aprint_naive(": IIC controller\n");
     97 	aprint_normal(": On-Chip IIC controller\n");
     98 
     99 	sc->sc_dev = self;
    100 	sc->sc_bust = oaa->opb_bt;
    101 
    102 	bus_space_map(sc->sc_bust, oaa->opb_addr, IIC_NREG, 0, &sc->sc_bush);
    103 
    104 	sc->sc_txen = 0;
    105 	sc->sc_tx = IIC_DIRECTCNTL_SCC | IIC_DIRECTCNTL_SDAC;
    106 	iic_tag_init(&sc->sc_i2c);
    107 	sc->sc_i2c.ic_cookie = sc;
    108 	sc->sc_i2c.ic_send_start = gpiic_send_start;
    109 	sc->sc_i2c.ic_send_stop = gpiic_send_stop;
    110 	sc->sc_i2c.ic_initiate_xfer = gpiic_initiate_xfer;
    111 	sc->sc_i2c.ic_read_byte = gpiic_read_byte;
    112 	sc->sc_i2c.ic_write_byte = gpiic_write_byte;
    113 
    114 	sc->sc_bops.ibo_set_dir = gpiic_set_dir;
    115 	sc->sc_bops.ibo_set_bits = gpiic_set_bits;
    116 	sc->sc_bops.ibo_read_bits = gpiic_read_bits;
    117 	sc->sc_bops.ibo_bits[I2C_BIT_SDA] = IIC_DIRECTCNTL_SDAC;
    118 	sc->sc_bops.ibo_bits[I2C_BIT_SCL] = IIC_DIRECTCNTL_SCC;
    119 	sc->sc_bops.ibo_bits[I2C_BIT_OUTPUT] = 1;
    120 	sc->sc_bops.ibo_bits[I2C_BIT_INPUT] = 0;
    121 
    122 	/*
    123 	 * Put the controller into Soft Reset. This allows us to
    124 	 * manually bit-bang the I2C clock/data lines.
    125 	 */
    126 	bus_space_write_1(sc->sc_bust, sc->sc_bush, IIC_XTCNTLSS,
    127 	    IIC_XTCNTLSS_SRST);
    128 	delay(10);
    129 	bus_space_write_1(sc->sc_bust, sc->sc_bush, IIC_DIRECTCNTL,
    130 	    IIC_DIRECTCNTL_SCC | IIC_DIRECTCNTL_SDAC);
    131 
    132 	iicbus_attach(self, &sc->sc_i2c);
    133 }
    134 
    135 static int
    136 gpiic_send_start(void *arg, int flags)
    137 {
    138 	struct gpiic_softc * const sc = arg;
    139 
    140 	return (i2c_bitbang_send_start(sc, flags, &sc->sc_bops));
    141 }
    142 
    143 static int
    144 gpiic_send_stop(void *arg, int flags)
    145 {
    146 	struct gpiic_softc * const sc = arg;
    147 
    148 	return (i2c_bitbang_send_stop(sc, flags, &sc->sc_bops));
    149 }
    150 
    151 static int
    152 gpiic_initiate_xfer(void *arg, i2c_addr_t addr, int flags)
    153 {
    154 	struct gpiic_softc * const sc = arg;
    155 
    156 	return (i2c_bitbang_initiate_xfer(sc, addr, flags, &sc->sc_bops));
    157 }
    158 
    159 static int
    160 gpiic_read_byte(void *arg, uint8_t *vp, int flags)
    161 {
    162 	struct gpiic_softc * const sc = arg;
    163 
    164 	return (i2c_bitbang_read_byte(sc, vp, flags, &sc->sc_bops));
    165 }
    166 
    167 static int
    168 gpiic_write_byte(void *arg, uint8_t v, int flags)
    169 {
    170 	struct gpiic_softc * const sc = arg;
    171 
    172 	return (i2c_bitbang_write_byte(sc, v, flags, &sc->sc_bops));
    173 }
    174 
    175 static void
    176 gpiic_set_dir(void *arg, uint32_t bits)
    177 {
    178 	struct gpiic_softc * const sc = arg;
    179 	uint8_t tx, txen;
    180 
    181 	txen = (uint8_t)bits;
    182 	if (sc->sc_txen == txen)
    183 		return;
    184 
    185 	sc->sc_txen = txen;
    186 
    187 	tx = sc->sc_tx;
    188 	if (sc->sc_txen == 0)
    189 		tx |= IIC_DIRECTCNTL_SDAC;
    190 	bus_space_write_1(sc->sc_bust, sc->sc_bush, IIC_DIRECTCNTL, tx);
    191 }
    192 
    193 static void
    194 gpiic_set_bits(void *arg, uint32_t bits)
    195 {
    196 	struct gpiic_softc * const sc = arg;
    197 
    198 	sc->sc_tx = (uint8_t)bits;
    199 	if (sc->sc_txen == 0)
    200 		bits |= IIC_DIRECTCNTL_SDAC;
    201 
    202 	bus_space_write_1(sc->sc_bust, sc->sc_bush, IIC_DIRECTCNTL, bits);
    203 }
    204 
    205 static uint32_t
    206 gpiic_read_bits(void *arg)
    207 {
    208 	struct gpiic_softc * const sc = arg;
    209 	uint8_t rv;
    210 
    211 	rv = bus_space_read_1(sc->sc_bust, sc->sc_bush, IIC_DIRECTCNTL) << 2;
    212 	rv &= (IIC_DIRECTCNTL_SCC | IIC_DIRECTCNTL_SDAC);
    213 
    214 	return ((uint32_t)rv);
    215 }
    216