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jbus-i2c.c revision 1.4
      1 /*	$NetBSD: jbus-i2c.c,v 1.4 2019/12/22 23:23:31 thorpej Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2018 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
     18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     19  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
     20  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     22  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     24  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
     25  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: jbus-i2c.c,v 1.4 2019/12/22 23:23:31 thorpej Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/device.h>
     34 #include <sys/errno.h>
     35 
     36 #include <sys/bus.h>
     37 #include <machine/autoconf.h>
     38 
     39 #include <dev/i2c/i2cvar.h>
     40 #include <dev/i2c/i2c_bitbang.h>
     41 
     42 #include <machine/openfirm.h>
     43 
     44 #ifdef JBUSI2C_DEBUG
     45 #define DPRINTF printf
     46 #else
     47 #define DPRINTF if (0) printf
     48 #endif
     49 
     50 /* I2C glue */
     51 static int jbusi2c_i2c_send_start(void *, int);
     52 static int jbusi2c_i2c_send_stop(void *, int);
     53 static int jbusi2c_i2c_initiate_xfer(void *, i2c_addr_t, int);
     54 static int jbusi2c_i2c_read_byte(void *, uint8_t *, int);
     55 static int jbusi2c_i2c_write_byte(void *, uint8_t, int);
     56 
     57 /* I2C bitbang glue */
     58 static void jbusi2c_i2cbb_set_bits(void *, uint32_t);
     59 static void jbusi2c_i2cbb_set_dir(void *, uint32_t);
     60 static uint32_t jbusi2c_i2cbb_read(void *);
     61 
     62 static const struct i2c_bitbang_ops jbusi2c_i2cbb_ops = {
     63 	jbusi2c_i2cbb_set_bits,
     64 	jbusi2c_i2cbb_set_dir,
     65 	jbusi2c_i2cbb_read,
     66 	{
     67 		2,	/* bit 1 is data */
     68 		1,	/* bit 0 is clock */
     69 		3,	/* direction register for both out */
     70 		1	/* data in, clock out */
     71 	}
     72 };
     73 
     74 static	int	jbusi2c_match(device_t, cfdata_t, void *);
     75 static	void	jbusi2c_attach(device_t, device_t, void *);
     76 
     77 struct jbusi2c_softc {
     78 	device_t sc_dev;
     79 	struct i2c_controller sc_i2c;
     80 	bus_space_tag_t sc_bustag;
     81 	bus_space_handle_t sc_regh;
     82 	int sc_node;
     83 };
     84 
     85 static void jbusi2c_setup_i2c(struct jbusi2c_softc *);
     86 
     87 CFATTACH_DECL_NEW(jbusi2c, sizeof(struct jbusi2c_softc),
     88     jbusi2c_match, jbusi2c_attach, NULL, NULL);
     89 
     90 /* schizo GPIO registers */
     91 #define DATA	0
     92 #define DIR	8
     93 
     94 int
     95 jbusi2c_match(device_t parent, cfdata_t match, void *aux)
     96 {
     97 	struct mainbus_attach_args *ma = aux;
     98 	char *str;
     99 
    100 	if (strcmp(ma->ma_name, "i2c") != 0)
    101 		return (0);
    102 
    103 	str = prom_getpropstring(ma->ma_node, "compatible");
    104 	if (strcmp(str, "jbus-i2c") == 0)
    105 		return (1);
    106 
    107 	return (0);
    108 }
    109 
    110 void
    111 jbusi2c_attach(device_t parent, device_t self, void *aux)
    112 {
    113 	struct jbusi2c_softc *sc = device_private(self);
    114 	struct mainbus_attach_args *ma = aux;
    115 
    116 	aprint_normal(": addr %" PRIx64 "\n", ma->ma_reg[0].ur_paddr);
    117 
    118 	sc->sc_dev = self;
    119 	sc->sc_node = ma->ma_node;
    120 	sc->sc_bustag = ma->ma_bustag;
    121 
    122 	if (bus_space_map(sc->sc_bustag, ma->ma_reg[0].ur_paddr, 16, 0,
    123 	    &sc->sc_regh)) {
    124 		aprint_error(": failed to map registers\n");
    125 		return;
    126 	}
    127 
    128 	jbusi2c_setup_i2c(sc);
    129 }
    130 
    131 
    132 
    133 static void
    134 jbusi2c_setup_i2c(struct jbusi2c_softc *sc)
    135 {
    136 	struct i2cbus_attach_args iba;
    137 	prop_array_t cfg;
    138 	prop_dictionary_t dev;
    139 	prop_data_t data;
    140 	prop_dictionary_t dict = device_properties(sc->sc_dev);
    141 	int devs, regs[2], addr;
    142 	char name[64], compat[256];
    143 
    144 	iic_tag_init(&sc->sc_i2c);
    145 	sc->sc_i2c.ic_cookie = sc;
    146 	sc->sc_i2c.ic_send_start = jbusi2c_i2c_send_start;
    147 	sc->sc_i2c.ic_send_stop = jbusi2c_i2c_send_stop;
    148 	sc->sc_i2c.ic_initiate_xfer = jbusi2c_i2c_initiate_xfer;
    149 	sc->sc_i2c.ic_read_byte = jbusi2c_i2c_read_byte;
    150 	sc->sc_i2c.ic_write_byte = jbusi2c_i2c_write_byte;
    151 
    152 	/* round up i2c devices */
    153 	devs = OF_child(sc->sc_node);
    154 	cfg = prop_array_create();
    155 	prop_dictionary_set(dict, "i2c-child-devices", cfg);
    156 	prop_object_release(cfg);
    157 	while (devs != 0) {
    158 		if (OF_getprop(devs, "name", name, 256) <= 0)
    159 			goto skip;
    160 		memset(compat, 0, sizeof(compat));
    161 		if (OF_getprop(devs, "compatible",
    162 		    compat, 255) <= 0)
    163 			goto skip;
    164 		if (OF_getprop(devs, "reg", regs, 8) <= 0)
    165 			goto skip;
    166 		if (regs[0] != 0) goto skip;
    167 		addr = (regs[1] & 0xff) >> 1;
    168 		DPRINTF("-> %s@%d,%x\n", name, regs[0], addr);
    169 		dev = prop_dictionary_create();
    170 		prop_dictionary_set_cstring(dev, "name", name);
    171 		data = prop_data_create_data(compat, strlen(compat)+1);
    172 		prop_dictionary_set(dev, "compatible", data);
    173 		prop_object_release(data);
    174 		prop_dictionary_set_uint32(dev, "addr", addr);
    175 		prop_dictionary_set_uint64(dev, "cookie", devs);
    176 		prop_array_add(cfg, dev);
    177 		prop_object_release(dev);
    178 	skip:
    179 		devs = OF_peer(devs);
    180 	}
    181 	memset(&iba, 0, sizeof(iba));
    182 	iba.iba_tag = &sc->sc_i2c;
    183 	config_found_ia(sc->sc_dev, "i2cbus", &iba,
    184 	    iicbus_print);
    185 }
    186 
    187 static inline void
    188 jbusi2c_write(struct jbusi2c_softc *sc, int reg, uint64_t bits)
    189 {
    190 	bus_space_write_8(sc->sc_bustag, sc->sc_regh, reg, bits);
    191 }
    192 
    193 static inline uint64_t
    194 jbusi2c_read(struct jbusi2c_softc *sc, int reg)
    195 {
    196 	return bus_space_read_8(sc->sc_bustag, sc->sc_regh, reg);
    197 }
    198 
    199 /* I2C bitbanging */
    200 static void
    201 jbusi2c_i2cbb_set_bits(void *cookie, uint32_t bits)
    202 {
    203 	struct jbusi2c_softc *sc = cookie;
    204 
    205 	jbusi2c_write(sc, DATA, bits);
    206 }
    207 
    208 static void
    209 jbusi2c_i2cbb_set_dir(void *cookie, uint32_t dir)
    210 {
    211 	struct jbusi2c_softc *sc = cookie;
    212 
    213 	jbusi2c_write(sc, DIR, dir);
    214 }
    215 
    216 static uint32_t
    217 jbusi2c_i2cbb_read(void *cookie)
    218 {
    219 	struct jbusi2c_softc *sc = cookie;
    220 
    221 	return jbusi2c_read(sc, DATA);
    222 }
    223 
    224 /* higher level I2C stuff */
    225 static int
    226 jbusi2c_i2c_send_start(void *cookie, int flags)
    227 {
    228 
    229 	return i2c_bitbang_send_start(cookie, flags, &jbusi2c_i2cbb_ops);
    230 }
    231 
    232 static int
    233 jbusi2c_i2c_send_stop(void *cookie, int flags)
    234 {
    235 
    236 	return i2c_bitbang_send_stop(cookie, flags, &jbusi2c_i2cbb_ops);
    237 }
    238 
    239 static int
    240 jbusi2c_i2c_initiate_xfer(void *cookie, i2c_addr_t addr, int flags)
    241 {
    242 
    243 	return i2c_bitbang_initiate_xfer(cookie, addr, flags,
    244 	    &jbusi2c_i2cbb_ops);
    245 }
    246 
    247 static int
    248 jbusi2c_i2c_read_byte(void *cookie, uint8_t *valp, int flags)
    249 {
    250 
    251 	return i2c_bitbang_read_byte(cookie, valp, flags, &jbusi2c_i2cbb_ops);
    252 }
    253 
    254 static int
    255 jbusi2c_i2c_write_byte(void *cookie, uint8_t val, int flags)
    256 {
    257 
    258 	return i2c_bitbang_write_byte(cookie, val, flags, &jbusi2c_i2cbb_ops);
    259 }
    260