Home | History | Annotate | Line # | Download | only in pci
tsciic.c revision 1.3 
      1 /*	$NetBSD: tsciic.c,v 1.3 2021/04/24 23:36:23 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 1.3 2021/04/24 23:36:23 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 */
     48 static int tsciic_send_start(void *, int);
     49 static int tsciic_send_stop(void *, int);
     50 static int tsciic_initiate_xfer(void *, i2c_addr_t, int);
     51 static int tsciic_read_byte(void *, uint8_t *, int);
     52 static int tsciic_write_byte(void *, uint8_t, int);
     53 
     54 /* I2C bitbang glue */
     55 static void tsciicbb_set_bits(void *, uint32_t);
     56 static void tsciicbb_set_dir(void *, uint32_t);
     57 static uint32_t tsciicbb_read(void *);
     58 
     59 #define MPD_BIT_SDA 0x01
     60 #define MPD_BIT_SCL 0x02
     61 static 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 
     73 void
     74 tsciic_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, CFARG_EOL);
     91 }
     92 
     93 /* I2C bitbanging */
     94 static void
     95 tsciicbb_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 
    106 static void
    107 tsciicbb_set_dir(void *cookie, uint32_t dir)
    108 {
    109 	/* Nothing to do */
    110 }
    111 
    112 static uint32_t
    113 tsciicbb_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 */
    125 static int
    126 tsciic_send_start(void *cookie, int flags)
    127 {
    128 	return (i2c_bitbang_send_start(cookie, flags, &tsciicbb_ops));
    129 }
    130 
    131 static int
    132 tsciic_send_stop(void *cookie, int flags)
    133 {
    134 	return (i2c_bitbang_send_stop(cookie, flags, &tsciicbb_ops));
    135 }
    136 
    137 static int
    138 tsciic_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 
    144 static int
    145 tsciic_read_byte(void *cookie, uint8_t *valp, int flags)
    146 {
    147 	return (i2c_bitbang_read_byte(cookie, valp, flags, &tsciicbb_ops));
    148 }
    149 
    150 static int
    151 tsciic_write_byte(void *cookie, uint8_t val, int flags)
    152 {
    153 	return (i2c_bitbang_write_byte(cookie, val, flags, &tsciicbb_ops));
    154 }
    155