1 /* $OpenBSD: dwiic_fdt.c,v 1.2 2024/03/29 22:08:09 kettenis Exp $ */
2 /*
3 * Copyright (c) 2023 Patrick Wildt <patrick@blueri.se>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include <sys/param.h>
19 #include <sys/device.h>
20 #include <sys/kernel.h>
21 #include <sys/systm.h>
22
23 #include <machine/bus.h>
24 #include <machine/fdt.h>
25
26 #include <dev/ofw/openfirm.h>
27 #include <dev/ofw/ofw_clock.h>
28 #include <dev/ofw/ofw_pinctrl.h>
29 #include <dev/ofw/fdt.h>
30
31 #include <dev/ic/dwiicvar.h>
32
33 static inline uint32_t
round_closest(uint64_t num,uint64_t den)34 round_closest(uint64_t num, uint64_t den)
35 {
36 return (num + (den / 2)) / den;
37 }
38
39 struct dwiic_fdt_softc {
40 struct dwiic_softc sc_sc;
41 int sc_node;
42 };
43
44 int dwiic_fdt_match(struct device *, void *, void *);
45 void dwiic_fdt_attach(struct device *, struct device *, void *);
46
47 const struct cfattach dwiic_fdt_ca = {
48 sizeof(struct dwiic_fdt_softc), dwiic_fdt_match, dwiic_fdt_attach
49 };
50
51 void dwiic_fdt_calc_timings(struct dwiic_fdt_softc *);
52 void dwiic_fdt_bus_scan(struct device *, struct i2cbus_attach_args *,
53 void *);
54
55 int
dwiic_fdt_match(struct device * parent,void * match,void * aux)56 dwiic_fdt_match(struct device *parent, void *match, void *aux)
57 {
58 struct fdt_attach_args *faa = aux;
59
60 return OF_is_compatible(faa->fa_node, "snps,designware-i2c");
61 }
62
63 void
dwiic_fdt_attach(struct device * parent,struct device * self,void * aux)64 dwiic_fdt_attach(struct device *parent, struct device *self, void *aux)
65 {
66 struct dwiic_fdt_softc *fsc = (struct dwiic_fdt_softc *)self;
67 struct dwiic_softc *sc = &fsc->sc_sc;
68 struct fdt_attach_args *faa = aux;
69 struct i2cbus_attach_args iba;
70
71 if (faa->fa_nreg < 1)
72 return;
73
74 sc->sc_iot = faa->fa_iot;
75 fsc->sc_node = faa->fa_node;
76 if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
77 faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
78 printf(": can't map registers\n");
79 return;
80 }
81
82 pinctrl_byname(faa->fa_node, "default");
83 reset_deassert_all(faa->fa_node);
84 clock_enable(faa->fa_node, NULL);
85
86 dwiic_fdt_calc_timings(fsc);
87
88 if (dwiic_init(sc)) {
89 printf(": can't initialize\n");
90 bus_space_unmap(sc->sc_iot, sc->sc_ioh, faa->fa_reg[0].size);
91 return;
92 }
93
94 /* leave the controller disabled */
95 dwiic_write(sc, DW_IC_INTR_MASK, 0);
96 dwiic_enable(sc, 0);
97 dwiic_read(sc, DW_IC_CLR_INTR);
98
99 sc->sc_ih = fdt_intr_establish(faa->fa_node, IPL_BIO,
100 dwiic_intr, sc, sc->sc_dev.dv_xname);
101
102 printf("\n");
103
104 rw_init(&sc->sc_i2c_lock, "dwiic");
105
106 sc->sc_i2c_tag.ic_cookie = sc;
107 sc->sc_i2c_tag.ic_acquire_bus = dwiic_i2c_acquire_bus;
108 sc->sc_i2c_tag.ic_release_bus = dwiic_i2c_release_bus;
109 sc->sc_i2c_tag.ic_exec = dwiic_i2c_exec;
110
111 bzero(&iba, sizeof iba);
112 iba.iba_name = "iic";
113 iba.iba_tag = &sc->sc_i2c_tag;
114 iba.iba_bus_scan = dwiic_fdt_bus_scan;
115 iba.iba_bus_scan_arg = &fsc->sc_node;
116 config_found(&sc->sc_dev, &iba, iicbus_print);
117 }
118
119 void
dwiic_fdt_calc_timings(struct dwiic_fdt_softc * fsc)120 dwiic_fdt_calc_timings(struct dwiic_fdt_softc *fsc)
121 {
122 struct dwiic_softc *sc = &fsc->sc_sc;
123 uint32_t sda_hold, sda_fall, scl_fall;
124 uint64_t freq;
125
126 freq = clock_get_frequency(fsc->sc_node, NULL);
127 if (freq == 0)
128 return;
129
130 sda_hold = OF_getpropint(fsc->sc_node, "i2c-sda-hold-time-ns", 300);
131 sda_fall = OF_getpropint(fsc->sc_node, "i2c-sda-falling-time-ns", 300);
132 scl_fall = OF_getpropint(fsc->sc_node, "i2c-scl-falling-time-ns", 300);
133
134 sc->sda_hold_time = round_closest(freq * sda_hold, 1000000000);
135
136 /* Standard-mode: tHIGH = 4.0 us; tLOW = 4.7 us */
137 sc->ss_hcnt = round_closest(freq * (4000 + sda_fall), 1000000000) - 3;
138 sc->ss_lcnt = round_closest(freq * (4700 + scl_fall), 1000000000) - 1;
139 /* Fast-mode: tHIGH = 0.6 us; tLOW = 1.3 us */
140 sc->fs_hcnt = round_closest(freq * (600 + sda_fall), 1000000000) - 3;
141 sc->fs_lcnt = round_closest(freq * (1300 + scl_fall), 1000000000) - 1;
142 }
143
144 void
dwiic_fdt_bus_scan(struct device * self,struct i2cbus_attach_args * iba,void * aux)145 dwiic_fdt_bus_scan(struct device *self, struct i2cbus_attach_args *iba,
146 void *aux)
147 {
148 int iba_node = *(int *)aux;
149 extern int iic_print(void *, const char *);
150 struct i2c_attach_args ia;
151 char name[32], status[32];
152 uint32_t reg[1];
153 int node;
154
155 for (node = OF_child(iba_node); node; node = OF_peer(node)) {
156 memset(name, 0, sizeof(name));
157 memset(status, 0, sizeof(status));
158 memset(reg, 0, sizeof(reg));
159
160 if (OF_getprop(node, "compatible", name, sizeof(name)) == -1)
161 continue;
162 if (name[0] == '\0')
163 continue;
164
165 if (OF_getprop(node, "status", status, sizeof(status)) > 0 &&
166 strcmp(status, "disabled") == 0)
167 continue;
168
169 if (OF_getprop(node, "reg", ®, sizeof(reg)) != sizeof(reg))
170 continue;
171
172 memset(&ia, 0, sizeof(ia));
173 ia.ia_tag = iba->iba_tag;
174 ia.ia_addr = bemtoh32(®[0]);
175 ia.ia_name = name;
176 ia.ia_cookie = &node;
177
178 config_found(self, &ia, iic_print);
179 }
180 }
181