--- /dev/null
+/* $OpenBSD: mpfiic.c,v 1.1 2022/02/16 13:07:36 visa Exp $ */
+
+/*
+ * Copyright (c) 2022 Visa Hankala
+ *
+ * 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.
+ */
+
+/*
+ * Driver for PolarFire SoC MSS I2C controller.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/malloc.h>
+
+#include <machine/bus.h>
+#include <machine/fdt.h>
+
+#define _I2C_PRIVATE
+#include <dev/i2c/i2cvar.h>
+
+#include <dev/ofw/fdt.h>
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/ofw_clock.h>
+#include <dev/ofw/ofw_misc.h>
+
+#define I2C_CTRL 0x0000
+#define I2C_CTRL_CR2 (1 << 7)
+#define I2C_CTRL_ENS1 (1 << 6)
+#define I2C_CTRL_STA (1 << 5)
+#define I2C_CTRL_STO (1 << 4)
+#define I2C_CTRL_SI (1 << 3)
+#define I2C_CTRL_AA (1 << 2)
+#define I2C_CTRL_CR1 (1 << 1)
+#define I2C_CTRL_CR0 (1 << 0)
+#define I2C_STATUS 0x0004
+#define I2C_DATA 0x0008
+#define I2C_SLAVE0ADR 0x000c
+#define I2C_SMBUS 0x0010
+#define I2C_FREQ 0x0014
+#define I2C_GLITCHREG 0x0018
+#define I2C_SLAVE1ADR 0x001c
+
+#define I2C_STATUS_START 0x08
+#define I2C_STATUS_RESTART 0x10
+#define I2C_STATUS_SLAW_ACK 0x18
+#define I2C_STATUS_DATAW_ACK 0x28
+#define I2C_STATUS_LOSTARB 0x38
+#define I2C_STATUS_SLAR_ACK 0x40
+#define I2C_STATUS_DATAR_ACK 0x50
+#define I2C_STATUS_DATAR_NACK 0x58
+#define I2C_STATUS_IDLE 0xf8
+
+struct mpfiic_softc {
+ struct device sc_dev;
+ bus_space_tag_t sc_iot;
+ bus_space_handle_t sc_ioh;
+ int sc_node;
+
+ struct i2c_bus sc_i2c_bus;
+ struct i2c_controller sc_i2c_tag;
+ struct rwlock sc_i2c_lock;
+
+ uint32_t sc_bus_freq; /* in Hz */
+ uint8_t sc_ctrl;
+ uint8_t sc_start_sent;
+};
+
+#define HREAD4(sc, reg) \
+ (bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
+#define HWRITE4(sc, reg, val) \
+ bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
+
+int mpfiic_match(struct device *, void *, void*);
+void mpfiic_attach(struct device *, struct device *, void *);
+
+int mpfiic_i2c_acquire_bus(void *, int);
+void mpfiic_i2c_release_bus(void *, int);
+int mpfiic_i2c_send_start(void *, int);
+int mpfiic_i2c_send_stop(void *, int);
+int mpfiic_i2c_initiate_xfer(void *, i2c_addr_t, int);
+int mpfiic_i2c_read_byte(void *, uint8_t *, int);
+int mpfiic_i2c_write_byte(void *, uint8_t, int);
+void mpfiic_i2c_scan(struct device *, struct i2cbus_attach_args *, void *);
+
+int mpfiic_wait(struct mpfiic_softc *, uint8_t);
+
+const struct cfattach mpfiic_ca = {
+ sizeof(struct mpfiic_softc), mpfiic_match, mpfiic_attach
+};
+
+struct cfdriver mpfiic_cd = {
+ NULL, "mpfiic", DV_DULL
+};
+
+static struct {
+ uint32_t div;
+ uint32_t cr;
+} mpfiic_clk_divs[] = {
+#ifdef notused
+ /* BCLK */
+ { 8, I2C_CTRL_CR2 | I2C_CTRL_CR1 | I2C_CTRL_CR0 },
+#endif
+ /* PCLK */
+ { 60, I2C_CTRL_CR2 | I2C_CTRL_CR1 },
+ { 120, I2C_CTRL_CR2 | I2C_CTRL_CR0 },
+ { 160, I2C_CTRL_CR1 | I2C_CTRL_CR0 },
+ { 192, I2C_CTRL_CR1 },
+ { 224, I2C_CTRL_CR0 },
+ { 256, 0 },
+ { 960, I2C_CTRL_CR2 },
+};
+
+int
+mpfiic_match(struct device *parent, void *match, void *aux)
+{
+ struct fdt_attach_args *faa = aux;
+
+ if (faa->fa_nreg < 1)
+ return 0;
+ return OF_is_compatible(faa->fa_node, "microchip,mpfs-i2c");
+}
+
+void
+mpfiic_attach(struct device *parent, struct device *self, void *aux)
+{
+ struct i2cbus_attach_args iba;
+ struct fdt_attach_args *faa = aux;
+ struct mpfiic_softc *sc = (struct mpfiic_softc *)self;
+ uint32_t i, bus_freq, clock_freq;
+
+ sc->sc_node = faa->fa_node;
+ sc->sc_iot = faa->fa_iot;
+
+ clock_freq = clock_get_frequency(sc->sc_node, NULL);
+ bus_freq = OF_getpropint(sc->sc_node, "clock-frequency", 100000);
+
+ /* Determine clock divider, assumes PCLK. */
+ for (i = 0; i < nitems(mpfiic_clk_divs) - 1; i++) {
+ if (clock_freq / mpfiic_clk_divs[i].div <= bus_freq)
+ break;
+ }
+ sc->sc_bus_freq = clock_freq / mpfiic_clk_divs[i].div;
+ sc->sc_ctrl = mpfiic_clk_divs[i].cr | I2C_CTRL_ENS1;
+
+ if (sc->sc_bus_freq == 0) {
+ printf(": invalid bus frequency\n");
+ return;
+ }
+
+ if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr, faa->fa_reg[0].size,
+ 0, &sc->sc_ioh) != 0) {
+ printf(": can't map registers\n");
+ return;
+ }
+
+ clock_enable_all(sc->sc_node);
+
+ /* Initialize the device. */
+ HWRITE4(sc, I2C_CTRL, sc->sc_ctrl);
+ HWRITE4(sc, I2C_CTRL, 0);
+
+ /* Disable slave address comparison. */
+ HWRITE4(sc, I2C_SLAVE0ADR, 0);
+ HWRITE4(sc, I2C_SLAVE1ADR, 0);
+
+ /* Disable SMBus logic, operate in standard I2C mode. */
+ HWRITE4(sc, I2C_SMBUS, 0);
+
+ printf("\n");
+
+ rw_init(&sc->sc_i2c_lock, "iiclk");
+ sc->sc_i2c_tag.ic_cookie = sc;
+ sc->sc_i2c_tag.ic_acquire_bus = mpfiic_i2c_acquire_bus;
+ sc->sc_i2c_tag.ic_release_bus = mpfiic_i2c_release_bus;
+ sc->sc_i2c_tag.ic_send_start = mpfiic_i2c_send_start;
+ sc->sc_i2c_tag.ic_send_stop = mpfiic_i2c_send_stop;
+ sc->sc_i2c_tag.ic_initiate_xfer = mpfiic_i2c_initiate_xfer;
+ sc->sc_i2c_tag.ic_read_byte = mpfiic_i2c_read_byte;
+ sc->sc_i2c_tag.ic_write_byte = mpfiic_i2c_write_byte;
+
+ memset(&iba, 0, sizeof(iba));
+ iba.iba_name = "iic";
+ iba.iba_tag = &sc->sc_i2c_tag;
+ iba.iba_bus_scan = mpfiic_i2c_scan;
+ iba.iba_bus_scan_arg = &sc->sc_node;
+ config_found(self, &iba, iicbus_print);
+
+ sc->sc_i2c_bus.ib_node = faa->fa_node;
+ sc->sc_i2c_bus.ib_ic = &sc->sc_i2c_tag;
+ i2c_register(&sc->sc_i2c_bus);
+}
+
+int
+mpfiic_i2c_acquire_bus(void *arg, int flags)
+{
+ struct mpfiic_softc *sc = arg;
+
+ if (cold || (flags & I2C_F_POLL))
+ return 0;
+
+ return rw_enter(&sc->sc_i2c_lock, RW_WRITE | RW_INTR);
+}
+
+void
+mpfiic_i2c_release_bus(void *arg, int flags)
+{
+ struct mpfiic_softc *sc = arg;
+
+ if (cold || (flags & I2C_F_POLL))
+ return;
+
+ rw_exit(&sc->sc_i2c_lock);
+}
+
+int
+mpfiic_i2c_send_start(void *cookie, int flags)
+{
+ struct mpfiic_softc *sc = cookie;
+ int error;
+ uint8_t nstatus;
+
+ HWRITE4(sc, I2C_CTRL, sc->sc_ctrl | I2C_CTRL_STA);
+
+ if (sc->sc_start_sent)
+ nstatus = I2C_STATUS_RESTART;
+ else
+ nstatus = I2C_STATUS_START;
+ error = mpfiic_wait(sc, nstatus);
+ if (error != 0)
+ return error;
+
+ sc->sc_start_sent = 1;
+
+ return 0;
+}
+
+int
+mpfiic_i2c_send_stop(void *cookie, int flags)
+{
+ struct mpfiic_softc *sc = cookie;
+
+ sc->sc_start_sent = 0;
+
+ HWRITE4(sc, I2C_CTRL, sc->sc_ctrl | I2C_CTRL_STO);
+
+ /* Let a few bus clock cycles pass. */
+ delay(4 * 1000000 / sc->sc_bus_freq);
+
+ /* Disable the device. This resets the state machine. */
+ HWRITE4(sc, I2C_CTRL, 0);
+
+ return 0;
+}
+
+int
+mpfiic_i2c_initiate_xfer(void *cookie, i2c_addr_t addr, int flags)
+{
+ struct mpfiic_softc *sc = cookie;
+ int error;
+ uint8_t mode, nstatus;
+
+ if (addr >= 0x80)
+ return EINVAL;
+
+ error = mpfiic_i2c_send_start(sc, flags);
+ if (error != 0)
+ return error;
+
+ if (flags & I2C_F_READ) {
+ mode = 0x01;
+ nstatus = I2C_STATUS_SLAR_ACK;
+ } else {
+ mode = 0x00;
+ nstatus = I2C_STATUS_SLAW_ACK;
+ }
+
+ HWRITE4(sc, I2C_DATA, (addr << 1) | mode);
+ HWRITE4(sc, I2C_CTRL, sc->sc_ctrl);
+
+ return mpfiic_wait(sc, nstatus);
+}
+
+int
+mpfiic_i2c_read_byte(void *cookie, uint8_t *datap, int flags)
+{
+ struct mpfiic_softc *sc = cookie;
+ int error;
+ uint8_t ack = 0, nstatus;
+
+ if ((flags & I2C_F_LAST) == 0)
+ ack = I2C_CTRL_AA;
+ HWRITE4(sc, I2C_CTRL, sc->sc_ctrl | ack);
+
+ if (flags & I2C_F_LAST)
+ nstatus = I2C_STATUS_DATAR_NACK;
+ else
+ nstatus = I2C_STATUS_DATAR_ACK;
+ error = mpfiic_wait(sc, nstatus);
+ if (error != 0)
+ return error;
+
+ *datap = HREAD4(sc, I2C_DATA);
+
+ if (flags & I2C_F_STOP)
+ error = mpfiic_i2c_send_stop(sc, flags);
+
+ return error;
+}
+
+int
+mpfiic_i2c_write_byte(void *cookie, uint8_t data, int flags)
+{
+ struct mpfiic_softc *sc = cookie;
+ int error;
+
+ HWRITE4(sc, I2C_DATA, data);
+ HWRITE4(sc, I2C_CTRL, sc->sc_ctrl);
+
+ error = mpfiic_wait(sc, I2C_STATUS_DATAW_ACK);
+ if (error != 0)
+ return error;
+
+ if (flags & I2C_F_STOP)
+ error = mpfiic_i2c_send_stop(sc, flags);
+
+ return error;
+}
+
+void
+mpfiic_i2c_scan(struct device *self, struct i2cbus_attach_args *iba, void *arg)
+{
+ struct i2c_attach_args ia;
+ char status[32];
+ char *compat;
+ uint32_t reg[1];
+ int iba_node = *(int *)arg;
+ int len, node;
+
+ for (node = OF_child(iba_node); node != 0; node = OF_peer(node)) {
+ memset(status, 0, sizeof(status));
+ if (OF_getprop(node, "status", status, sizeof(status)) > 0 &&
+ strcmp(status, "disabled") == 0)
+ continue;
+
+ memset(reg, 0, sizeof(reg));
+ if (OF_getprop(node, "reg", ®, sizeof(reg)) != sizeof(reg))
+ continue;
+
+ len = OF_getproplen(node, "compatible");
+ if (len <= 0)
+ continue;
+
+ compat = malloc(len, M_TEMP, M_WAITOK);
+ OF_getprop(node, "compatible", compat, len);
+
+ memset(&ia, 0, sizeof(ia));
+ ia.ia_tag = iba->iba_tag;
+ ia.ia_addr = bemtoh32(®[0]);
+ ia.ia_name = compat;
+ ia.ia_namelen = len;
+ ia.ia_cookie = &node;
+ config_found(self, &ia, iic_print);
+
+ free(compat, M_TEMP, len);
+ }
+}
+
+int
+mpfiic_wait(struct mpfiic_softc *sc, uint8_t nstatus)
+{
+ int timeout;
+ uint8_t ctrl, status;
+
+ for (timeout = 100000; timeout > 0; timeout--) {
+ ctrl = HREAD4(sc, I2C_CTRL);
+ if (ctrl & I2C_CTRL_SI)
+ break;
+ delay(1);
+ }
+ if (timeout == 0)
+ return ETIMEDOUT;
+
+ status = HREAD4(sc, I2C_STATUS);
+ if (status != nstatus)
+ return EIO;
+
+ return 0;
+}
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