--- /dev/null
+/* $OpenBSD: iicmux.c,v 1.1 2021/11/21 11:02:21 kettenis Exp $ */
+/*
+ * Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * 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/systm.h>
+#include <sys/malloc.h>
+#include <sys/device.h>
+
+#include <machine/bus.h>
+#include <machine/fdt.h>
+
+#define _I2C_PRIVATE
+#include <dev/i2c/i2cvar.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/ofw_misc.h>
+#include <dev/ofw/ofw_pinctrl.h>
+
+#define IICMUX_MAX_CHANNELS 4
+
+struct iicmux_bus {
+ struct iicmux_softc *pb_sc;
+ int pb_node;
+ int pb_channel;
+ struct i2c_controller pb_ic;
+ struct i2c_bus pb_ib;
+ struct device *pb_iic;
+};
+
+struct iicmux_softc {
+ struct device sc_dev;
+ i2c_tag_t sc_tag;
+
+ int sc_node;
+ int sc_channel;
+ int sc_nchannel;
+ struct iicmux_bus sc_bus[IICMUX_MAX_CHANNELS];
+ const char *sc_busnames[IICMUX_MAX_CHANNELS];
+ struct rwlock sc_lock;
+
+ int sc_enable;
+};
+
+int iicmux_match(struct device *, void *, void *);
+void iicmux_attach(struct device *, struct device *, void *);
+
+struct cfattach iicmux_ca = {
+ sizeof(struct iicmux_softc), iicmux_match, iicmux_attach
+};
+
+struct cfdriver iicmux_cd = {
+ NULL, "iicmux", DV_DULL
+};
+
+int iicmux_acquire_bus(void *, int);
+void iicmux_release_bus(void *, int);
+int iicmux_exec(void *, i2c_op_t, i2c_addr_t, const void *, size_t,
+ void *, size_t, int);
+void iicmux_bus_scan(struct device *, struct i2cbus_attach_args *, void *);
+
+int
+iicmux_match(struct device *parent, void *match, void *aux)
+{
+ struct fdt_attach_args *faa = aux;
+
+ return OF_is_compatible(faa->fa_node, "i2c-mux-pinctrl");
+}
+
+void
+iicmux_attach(struct device *parent, struct device *self, void *aux)
+{
+ struct iicmux_softc *sc = (struct iicmux_softc *)self;
+ struct fdt_attach_args *faa = aux;
+ int node = faa->fa_node;
+ uint32_t phandle;
+ char *names;
+ char *name;
+ char *end;
+ int len;
+
+ sc->sc_channel = -1; /* unknown */
+ rw_init(&sc->sc_lock, sc->sc_dev.dv_xname);
+
+ phandle = OF_getpropint(node, "i2c-parent", 0);
+ sc->sc_tag = i2c_byphandle(phandle);
+ if (sc->sc_tag == NULL) {
+ printf(": can't find parent bus\n");
+ return;
+ }
+
+ len = OF_getproplen(node, "pinctrl-names");
+ if (len <= 0) {
+ printf(": no channels\n");
+ return;
+ }
+
+ names = malloc(len, M_DEVBUF, M_WAITOK);
+ OF_getprop(node, "pinctrl-names", names, len);
+ end = names + len;
+ name = names;
+ while (name < end) {
+ if (strcmp(name, "idle") == 0)
+ break;
+
+ if (sc->sc_nchannel >= IICMUX_MAX_CHANNELS) {
+ printf(": too many channels\n");
+ free(names, M_DEVBUF, len);
+ return;
+ }
+
+ sc->sc_busnames[sc->sc_nchannel] = name;
+ name += strlen(name) + 1;
+ sc->sc_nchannel++;
+ }
+
+ printf("\n");
+
+ sc->sc_node = node;
+ for (node = OF_child(node); node; node = OF_peer(node)) {
+ struct i2cbus_attach_args iba;
+ struct iicmux_bus *pb;
+ uint32_t channel;
+
+ channel = OF_getpropint(node, "reg", -1);
+ if (channel >= sc->sc_nchannel)
+ continue;
+
+ pb = &sc->sc_bus[channel];
+ pb->pb_sc = sc;
+ pb->pb_node = node;
+ pb->pb_channel = channel;
+ pb->pb_ic.ic_cookie = pb;
+ pb->pb_ic.ic_acquire_bus = iicmux_acquire_bus;
+ pb->pb_ic.ic_release_bus = iicmux_release_bus;
+ pb->pb_ic.ic_exec = iicmux_exec;
+
+ /* Configure the child busses. */
+ memset(&iba, 0, sizeof(iba));
+ iba.iba_name = "iic";
+ iba.iba_tag = &pb->pb_ic;
+ iba.iba_bus_scan = iicmux_bus_scan;
+ iba.iba_bus_scan_arg = &pb->pb_node;
+
+ config_found(&sc->sc_dev, &iba, iicbus_print);
+
+ pb->pb_ib.ib_node = node;
+ pb->pb_ib.ib_ic = &pb->pb_ic;
+ i2c_register(&pb->pb_ib);
+ }
+}
+
+int
+iicmux_set_channel(struct iicmux_softc *sc, int channel, int flags)
+{
+ int error;
+
+ if (channel < -1 || channel >= sc->sc_nchannel)
+ return ENXIO;
+
+ if (sc->sc_channel == channel)
+ return 0;
+
+ error = pinctrl_byname(sc->sc_node, sc->sc_busnames[channel]);
+ if (error == 0)
+ sc->sc_channel = channel;
+
+ return error ? EIO : 0;
+}
+
+int
+iicmux_acquire_bus(void *cookie, int flags)
+{
+ struct iicmux_bus *pb = cookie;
+ struct iicmux_softc *sc = pb->pb_sc;
+ int rwflags = RW_WRITE;
+ int error;
+
+ if (flags & I2C_F_POLL)
+ rwflags |= RW_NOSLEEP;
+
+ error = rw_enter(&sc->sc_lock, rwflags);
+ if (error)
+ return error;
+
+ /* Acquire parent bus. */
+ error = iic_acquire_bus(sc->sc_tag, flags);
+ if (error) {
+ rw_exit_write(&sc->sc_lock);
+ return error;
+ }
+
+ error = iicmux_set_channel(sc, pb->pb_channel, flags);
+ if (error) {
+ iic_release_bus(sc->sc_tag, flags);
+ rw_exit_write(&sc->sc_lock);
+ return error;
+ }
+
+ return 0;
+}
+
+void
+iicmux_release_bus(void *cookie, int flags)
+{
+ struct iicmux_bus *pb = cookie;
+ struct iicmux_softc *sc = pb->pb_sc;
+
+ if (pinctrl_byname(sc->sc_node, "idle") == 0)
+ sc->sc_channel = -1;
+
+ /* Release parent bus. */
+ iic_release_bus(sc->sc_tag, flags);
+ rw_exit_write(&sc->sc_lock);
+}
+
+int
+iicmux_exec(void *cookie, i2c_op_t op, i2c_addr_t addr, const void *cmd,
+ size_t cmdlen, void *buf, size_t buflen, int flags)
+{
+ struct iicmux_bus *pb = cookie;
+ struct iicmux_softc *sc = pb->pb_sc;
+
+ rw_assert_wrlock(&sc->sc_lock);
+
+ /* Issue the transaction on the parent bus. */
+ return iic_exec(sc->sc_tag, op, addr, cmd, cmdlen, buf, buflen, flags);
+}
+
+void
+iicmux_bus_scan(struct device *self, struct i2cbus_attach_args *iba, void *arg)
+{
+ int iba_node = *(int *)arg;
+ struct i2c_attach_args ia;
+ char name[32];
+ uint32_t reg[1];
+ int node;
+
+ for (node = OF_child(iba_node); node; node = OF_peer(node)) {
+ memset(name, 0, sizeof(name));
+ memset(reg, 0, sizeof(reg));
+
+ if (OF_getprop(node, "compatible", name, sizeof(name)) == -1)
+ continue;
+ if (name[0] == '\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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