--- /dev/null
+/* $OpenBSD: dwiic_fdt.c,v 1.1 2023/08/29 12:09:40 kettenis Exp $ */
+/*
+ * Copyright (c) 2023 Patrick Wildt <patrick@blueri.se>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/device.h>
+#include <sys/kernel.h>
+#include <sys/systm.h>
+
+#include <machine/bus.h>
+#include <machine/fdt.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/ofw_clock.h>
+#include <dev/ofw/ofw_pinctrl.h>
+#include <dev/ofw/fdt.h>
+
+#include <dev/ic/dwiicvar.h>
+
+static inline uint32_t
+round_closest(uint64_t num, uint64_t den)
+{
+ return (num + (den / 2)) / den;
+}
+
+struct dwiic_fdt_softc {
+ struct dwiic_softc sc_sc;
+ int sc_node;
+};
+
+int dwiic_fdt_match(struct device *, void *, void *);
+void dwiic_fdt_attach(struct device *, struct device *, void *);
+
+const struct cfattach dwiic_fdt_ca = {
+ sizeof(struct dwiic_fdt_softc), dwiic_fdt_match, dwiic_fdt_attach
+};
+
+void dwiic_fdt_bus_scan(struct device *, struct i2cbus_attach_args *,
+ void *);
+
+int
+dwiic_fdt_match(struct device *parent, void *match, void *aux)
+{
+ struct fdt_attach_args *faa = aux;
+
+ return OF_is_compatible(faa->fa_node, "snps,designware-i2c");
+}
+
+void
+dwiic_fdt_attach(struct device *parent, struct device *self, void *aux)
+{
+ struct dwiic_fdt_softc *fsc = (struct dwiic_fdt_softc *)self;
+ struct dwiic_softc *sc = &fsc->sc_sc;
+ struct fdt_attach_args *faa = aux;
+ struct i2cbus_attach_args iba;
+ uint32_t sda_hold, sda_fall, scl_fall;
+ uint64_t freq;
+
+ if (faa->fa_nreg < 1)
+ return;
+
+ sc->sc_iot = faa->fa_iot;
+ fsc->sc_node = faa->fa_node;
+ if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
+ faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
+ printf(": can't map registers\n");
+ return;
+ }
+
+ pinctrl_byname(faa->fa_node, "default");
+ reset_deassert_all(faa->fa_node);
+ clock_enable(faa->fa_node, NULL);
+
+ freq = clock_get_frequency(faa->fa_node, NULL);
+ sda_hold = OF_getpropint(faa->fa_node, "i2c-sda-hold-time-ns", 300);
+ sda_fall = OF_getpropint(faa->fa_node, "i2c-sda-falling-time-ns", 300);
+ scl_fall = OF_getpropint(faa->fa_node, "i2c-scl-falling-time-ns", 300);
+
+ sc->sda_hold_time = round_closest(freq * sda_hold, 1000000000);
+
+ /* Standard-mode: tHIGH = 4.0 us; tLOW = 4.7 us */
+ sc->ss_hcnt = round_closest(freq * (4000 + sda_fall), 1000000000) - 3;
+ sc->ss_lcnt = round_closest(freq * (4700 + scl_fall), 1000000000) - 1;
+ /* Fast-mode: tHIGH = 0.6 us; tLOW = 1.3 us */
+ sc->fs_hcnt = round_closest(freq * (600 + sda_fall), 1000000000) - 3;
+ sc->fs_lcnt = round_closest(freq * (1300 + scl_fall), 1000000000) - 1;
+
+ if (dwiic_init(sc)) {
+ printf(": can't initialize\n");
+ bus_space_unmap(sc->sc_iot, sc->sc_ioh, faa->fa_reg[0].size);
+ return;
+ }
+
+ /* leave the controller disabled */
+ dwiic_write(sc, DW_IC_INTR_MASK, 0);
+ dwiic_enable(sc, 0);
+ dwiic_read(sc, DW_IC_CLR_INTR);
+
+ sc->sc_ih = fdt_intr_establish(faa->fa_node, IPL_BIO,
+ dwiic_intr, sc, sc->sc_dev.dv_xname);
+
+ printf("\n");
+
+ rw_init(&sc->sc_i2c_lock, "dwiic");
+
+ sc->sc_i2c_tag.ic_cookie = sc;
+ sc->sc_i2c_tag.ic_acquire_bus = dwiic_i2c_acquire_bus;
+ sc->sc_i2c_tag.ic_release_bus = dwiic_i2c_release_bus;
+ sc->sc_i2c_tag.ic_exec = dwiic_i2c_exec;
+
+ bzero(&iba, sizeof iba);
+ iba.iba_name = "iic";
+ iba.iba_tag = &sc->sc_i2c_tag;
+ iba.iba_bus_scan = dwiic_fdt_bus_scan;
+ iba.iba_bus_scan_arg = &fsc->sc_node;
+ config_found(&sc->sc_dev, &iba, iicbus_print);
+}
+
+void
+dwiic_fdt_bus_scan(struct device *self, struct i2cbus_attach_args *iba,
+ void *aux)
+{
+ int iba_node = *(int *)aux;
+ extern int iic_print(void *, const char *);
+ struct i2c_attach_args ia;
+ char name[32], status[32];
+ uint32_t reg[1];
+ int node;
+
+ for (node = OF_child(iba_node); node; node = OF_peer(node)) {
+ memset(name, 0, sizeof(name));
+ memset(status, 0, sizeof(status));
+ memset(reg, 0, sizeof(reg));
+
+ if (OF_getprop(node, "compatible", name, sizeof(name)) == -1)
+ continue;
+ if (name[0] == '\0')
+ continue;
+
+ if (OF_getprop(node, "status", status, sizeof(status)) > 0 &&
+ strcmp(status, "disabled") == 0)
+ continue;
+
+ if (OF_getprop(node, "reg", ®, sizeof(reg)) != sizeof(reg))
+ continue;
+
+ memset(&ia, 0, sizeof(ia));
+ ia.ia_tag = iba->iba_tag;
+ ia.ia_addr = bemtoh32(®[0]);
+ ia.ia_name = name;
+ ia.ia_cookie = &node;
+
+ config_found(self, &ia, iic_print);
+ }
+}
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