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Date:      Sun, 14 Feb 2016 23:51:13 +0000 (UTC)
From:      Andrew Turner <andrew@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r295622 - in head/sys: arm/mv conf dev/iicbus/twsi
Message-ID:  <201602142351.u1ENpDap044812@repo.freebsd.org>

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Author: andrew
Date: Sun Feb 14 23:51:13 2016
New Revision: 295622
URL: https://svnweb.freebsd.org/changeset/base/295622

Log:
  Move the twsi driver source to be under iicbus. It is in a separate
  directory as it is expected multiple attachments will be added for the SoC
  families that use this hardware.
  
  Sponsored by:	ABT Systems Ltd

Added:
  head/sys/dev/iicbus/twsi/
  head/sys/dev/iicbus/twsi/twsi.c
     - copied unchanged from r295621, head/sys/arm/mv/twsi.c
Deleted:
  head/sys/arm/mv/twsi.c
Modified:
  head/sys/arm/mv/files.mv
  head/sys/conf/files.arm

Modified: head/sys/arm/mv/files.mv
==============================================================================
--- head/sys/arm/mv/files.mv	Sun Feb 14 23:42:07 2016	(r295621)
+++ head/sys/arm/mv/files.mv	Sun Feb 14 23:51:13 2016	(r295622)
@@ -19,7 +19,6 @@ arm/mv/mv_machdep.c		standard
 arm/mv/mv_pci.c			optional	pci
 arm/mv/mv_ts.c			standard
 arm/mv/timer.c			standard
-arm/mv/twsi.c			optional	twsi
 
 dev/cesa/cesa.c			optional	cesa
 dev/mge/if_mge.c		optional	mge

Modified: head/sys/conf/files.arm
==============================================================================
--- head/sys/conf/files.arm	Sun Feb 14 23:42:07 2016	(r295621)
+++ head/sys/conf/files.arm	Sun Feb 14 23:51:13 2016	(r295622)
@@ -101,6 +101,7 @@ dev/fb/fb.c			optional	sc
 dev/fdt/fdt_arm_platform.c	optional	platform fdt
 dev/hwpmc/hwpmc_arm.c		optional	hwpmc
 dev/hwpmc/hwpmc_armv7.c		optional	hwpmc armv6
+dev/iicbus/twsi/twsi.c		optional	twsi
 dev/psci/psci.c			optional	psci
 dev/psci/psci_arm.S		optional	psci
 dev/syscons/scgfbrndr.c		optional	sc

Copied: head/sys/dev/iicbus/twsi/twsi.c (from r295621, head/sys/arm/mv/twsi.c)
==============================================================================
--- /dev/null	00:00:00 1970	(empty, because file is newly added)
+++ head/sys/dev/iicbus/twsi/twsi.c	Sun Feb 14 23:51:13 2016	(r295622, copy of r295621, head/sys/arm/mv/twsi.c)
@@ -0,0 +1,644 @@
+/*-
+ * Copyright (C) 2008 MARVELL INTERNATIONAL LTD.
+ * All rights reserved.
+ *
+ * Developed by Semihalf.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of MARVELL nor the names of contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Driver for the TWSI (aka I2C, aka IIC) bus controller found on Marvell
+ * SoCs. Supports master operation only, and works in polling mode.
+ *
+ * Calls to DELAY() are needed per Application Note AN-179 "TWSI Software
+ * Guidelines for Discovery(TM), Horizon (TM) and Feroceon(TM) Devices".
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <sys/resource.h>
+
+#include <machine/_inttypes.h>
+#include <machine/bus.h>
+#include <machine/resource.h>
+
+#include <sys/rman.h>
+
+#include <sys/lock.h>
+#include <sys/mutex.h>
+
+#include <dev/iicbus/iiconf.h>
+#include <dev/iicbus/iicbus.h>
+#include <dev/fdt/fdt_common.h>
+#include <dev/ofw/ofw_bus.h>
+#include <dev/ofw/ofw_bus_subr.h>
+
+#include <arm/mv/mvvar.h>
+
+#include "iicbus_if.h"
+
+#define MV_TWSI_NAME		"twsi"
+#define	IICBUS_DEVNAME		"iicbus"
+
+#define TWSI_SLAVE_ADDR		0x00
+#define TWSI_EXT_SLAVE_ADDR	0x10
+#define TWSI_DATA		0x04
+
+#define TWSI_CONTROL		0x08
+#define TWSI_CONTROL_ACK	(1 << 2)
+#define TWSI_CONTROL_IFLG	(1 << 3)
+#define TWSI_CONTROL_STOP	(1 << 4)
+#define TWSI_CONTROL_START	(1 << 5)
+#define TWSI_CONTROL_TWSIEN	(1 << 6)
+#define TWSI_CONTROL_INTEN	(1 << 7)
+
+#define TWSI_STATUS			0x0c
+#define TWSI_STATUS_START		0x08
+#define TWSI_STATUS_RPTD_START		0x10
+#define TWSI_STATUS_ADDR_W_ACK		0x18
+#define TWSI_STATUS_DATA_WR_ACK		0x28
+#define TWSI_STATUS_ADDR_R_ACK		0x40
+#define TWSI_STATUS_DATA_RD_ACK		0x50
+#define TWSI_STATUS_DATA_RD_NOACK	0x58
+
+#define TWSI_BAUD_RATE		0x0c
+#define	TWSI_BAUD_RATE_PARAM(M,N)	((((M) << 3) | ((N) & 0x7)) & 0x7f)
+#define	TWSI_BAUD_RATE_RAW(C,M,N)	((C)/((10*(M+1))<<(N+1)))
+#define	TWSI_BAUD_RATE_SLOW		50000	/* 50kHz */
+#define	TWSI_BAUD_RATE_FAST		100000	/* 100kHz */
+
+#define TWSI_SOFT_RESET		0x1c
+
+#define TWSI_DEBUG
+#undef TWSI_DEBUG
+
+#ifdef  TWSI_DEBUG
+#define debugf(fmt, args...) do { printf("%s(): ", __func__); printf(fmt,##args); } while (0)
+#else
+#define debugf(fmt, args...)
+#endif
+
+struct mv_twsi_softc {
+	device_t	dev;
+	struct resource	*res[1];	/* SYS_RES_MEMORY */
+	struct mtx	mutex;
+	device_t	iicbus;
+};
+
+static struct mv_twsi_baud_rate {
+	uint32_t	raw;
+	int		param;
+	int		m;
+	int		n;
+} baud_rate[IIC_FASTEST + 1];
+
+static int mv_twsi_probe(device_t);
+static int mv_twsi_attach(device_t);
+static int mv_twsi_detach(device_t);
+
+static int mv_twsi_reset(device_t dev, u_char speed, u_char addr,
+    u_char *oldaddr);
+static int mv_twsi_repeated_start(device_t dev, u_char slave, int timeout);
+static int mv_twsi_start(device_t dev, u_char slave, int timeout);
+static int mv_twsi_stop(device_t dev);
+static int mv_twsi_read(device_t dev, char *buf, int len, int *read, int last,
+    int delay);
+static int mv_twsi_write(device_t dev, const char *buf, int len, int *sent,
+    int timeout);
+
+static struct resource_spec res_spec[] = {
+	{ SYS_RES_MEMORY, 0, RF_ACTIVE },
+	{ -1, 0 }
+};
+
+static struct ofw_compat_data compat_data[] = {
+	{ "mrvl,twsi",			true },
+	{ "marvell,mv64xxx-i2c",	true },
+	{ NULL,				false }
+};
+
+static device_method_t mv_twsi_methods[] = {
+	/* device interface */
+	DEVMETHOD(device_probe,		mv_twsi_probe),
+	DEVMETHOD(device_attach,	mv_twsi_attach),
+	DEVMETHOD(device_detach,	mv_twsi_detach),
+
+	/* iicbus interface */
+	DEVMETHOD(iicbus_callback, iicbus_null_callback),
+	DEVMETHOD(iicbus_repeated_start, mv_twsi_repeated_start),
+	DEVMETHOD(iicbus_start,		mv_twsi_start),
+	DEVMETHOD(iicbus_stop,		mv_twsi_stop),
+	DEVMETHOD(iicbus_write,		mv_twsi_write),
+	DEVMETHOD(iicbus_read,		mv_twsi_read),
+	DEVMETHOD(iicbus_reset,		mv_twsi_reset),
+	DEVMETHOD(iicbus_transfer,	iicbus_transfer_gen),
+	{ 0, 0 }
+};
+
+static devclass_t mv_twsi_devclass;
+
+static driver_t mv_twsi_driver = {
+	MV_TWSI_NAME,
+	mv_twsi_methods,
+	sizeof(struct mv_twsi_softc),
+};
+
+DRIVER_MODULE(twsi, simplebus, mv_twsi_driver, mv_twsi_devclass, 0, 0);
+DRIVER_MODULE(iicbus, twsi, iicbus_driver, iicbus_devclass, 0, 0);
+MODULE_DEPEND(twsi, iicbus, 1, 1, 1);
+
+static __inline uint32_t
+TWSI_READ(struct mv_twsi_softc *sc, bus_size_t off)
+{
+
+	return (bus_read_4(sc->res[0], off));
+}
+
+static __inline void
+TWSI_WRITE(struct mv_twsi_softc *sc, bus_size_t off, uint32_t val)
+{
+
+	bus_write_4(sc->res[0], off, val);
+}
+
+static __inline void
+twsi_control_clear(struct mv_twsi_softc *sc, uint32_t mask)
+{
+	uint32_t val;
+
+	val = TWSI_READ(sc, TWSI_CONTROL);
+	val &= ~mask;
+	TWSI_WRITE(sc, TWSI_CONTROL, val);
+}
+
+static __inline void
+twsi_control_set(struct mv_twsi_softc *sc, uint32_t mask)
+{
+	uint32_t val;
+
+	val = TWSI_READ(sc, TWSI_CONTROL);
+	val |= mask;
+	TWSI_WRITE(sc, TWSI_CONTROL, val);
+}
+
+static __inline void
+twsi_clear_iflg(struct mv_twsi_softc *sc)
+{
+
+	DELAY(1000);
+	twsi_control_clear(sc, TWSI_CONTROL_IFLG);
+	DELAY(1000);
+}
+
+
+/*
+ * timeout given in us
+ * returns
+ *   0 on sucessfull mask change
+ *   non-zero on timeout
+ */
+static int
+twsi_poll_ctrl(struct mv_twsi_softc *sc, int timeout, uint32_t mask)
+{
+
+	timeout /= 10;
+	while (!(TWSI_READ(sc, TWSI_CONTROL) & mask)) {
+		DELAY(10);
+		if (--timeout < 0)
+			return (timeout);
+	}
+	return (0);
+}
+
+
+/*
+ * 'timeout' is given in us. Note also that timeout handling is not exact --
+ * twsi_locked_start() total wait can be more than 2 x timeout
+ * (twsi_poll_ctrl() is called twice). 'mask' can be either TWSI_STATUS_START
+ * or TWSI_STATUS_RPTD_START
+ */
+static int
+twsi_locked_start(device_t dev, struct mv_twsi_softc *sc, int32_t mask,
+    u_char slave, int timeout)
+{
+	int read_access, iflg_set = 0;
+	uint32_t status;
+
+	mtx_assert(&sc->mutex, MA_OWNED);
+
+	if (mask == TWSI_STATUS_RPTD_START)
+		/* read IFLG to know if it should be cleared later; from NBSD */
+		iflg_set = TWSI_READ(sc, TWSI_CONTROL) & TWSI_CONTROL_IFLG;
+
+	twsi_control_set(sc, TWSI_CONTROL_START);
+
+	if (mask == TWSI_STATUS_RPTD_START && iflg_set) {
+		debugf("IFLG set, clearing\n");
+		twsi_clear_iflg(sc);
+	}
+
+	/*
+	 * Without this delay we timeout checking IFLG if the timeout is 0.
+	 * NBSD driver always waits here too.
+	 */
+	DELAY(1000);
+
+	if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
+		debugf("timeout sending %sSTART condition\n",
+		    mask == TWSI_STATUS_START ? "" : "repeated ");
+		return (IIC_ETIMEOUT);
+	}
+
+	status = TWSI_READ(sc, TWSI_STATUS);
+	if (status != mask) {
+		debugf("wrong status (%02x) after sending %sSTART condition\n",
+		    status, mask == TWSI_STATUS_START ? "" : "repeated ");
+		return (IIC_ESTATUS);
+	}
+
+	TWSI_WRITE(sc, TWSI_DATA, slave);
+	DELAY(1000);
+	twsi_clear_iflg(sc);
+
+	if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
+		debugf("timeout sending slave address\n");
+		return (IIC_ETIMEOUT);
+	}
+	
+	read_access = (slave & 0x1) ? 1 : 0;
+	status = TWSI_READ(sc, TWSI_STATUS);
+	if (status != (read_access ?
+	    TWSI_STATUS_ADDR_R_ACK : TWSI_STATUS_ADDR_W_ACK)) {
+		debugf("no ACK (status: %02x) after sending slave address\n",
+		    status);
+		return (IIC_ENOACK);
+	}
+
+	return (IIC_NOERR);
+}
+
+static int
+mv_twsi_probe(device_t dev)
+{
+
+	if (!ofw_bus_status_okay(dev))
+		return (ENXIO);
+
+	if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data)
+		return (ENXIO);
+
+	device_set_desc(dev, "Marvell Integrated I2C Bus Controller");
+	return (BUS_PROBE_DEFAULT);
+}
+
+#define	ABSSUB(a,b)	(((a) > (b)) ? (a) - (b) : (b) - (a))
+static void
+mv_twsi_cal_baud_rate(const uint32_t target, struct mv_twsi_baud_rate *rate)
+{
+	uint32_t clk, cur, diff, diff0;
+	int m, n, m0, n0;
+
+	/* Calculate baud rate. */
+	m0 = n0 = 4;	/* Default values on reset */
+	diff0 = 0xffffffff;
+	clk = get_tclk();
+
+	for (n = 0; n < 8; n++) {
+		for (m = 0; m < 16; m++) {
+			cur = TWSI_BAUD_RATE_RAW(clk,m,n);
+			diff = ABSSUB(target, cur);
+			if (diff < diff0) {
+				m0 = m;
+				n0 = n;
+				diff0 = diff;
+			}
+		}
+	}
+	rate->raw = TWSI_BAUD_RATE_RAW(clk, m0, n0);
+	rate->param = TWSI_BAUD_RATE_PARAM(m0, n0);
+	rate->m = m0;
+	rate->n = n0;
+}
+
+static int
+mv_twsi_attach(device_t dev)
+{
+	struct mv_twsi_softc *sc;
+	phandle_t child, iicbusnode;
+	device_t childdev;
+	struct iicbus_ivar *devi;
+	char dname[32];	/* 32 is taken from struct u_device */
+	uint32_t paddr;
+	int len, error;
+
+	sc = device_get_softc(dev);
+	sc->dev = dev;
+	bzero(baud_rate, sizeof(baud_rate));
+
+	mtx_init(&sc->mutex, device_get_nameunit(dev), MV_TWSI_NAME, MTX_DEF);
+
+	/* Allocate IO resources */
+	if (bus_alloc_resources(dev, res_spec, sc->res)) {
+		device_printf(dev, "could not allocate resources\n");
+		mv_twsi_detach(dev);
+		return (ENXIO);
+	}
+
+	mv_twsi_cal_baud_rate(TWSI_BAUD_RATE_SLOW, &baud_rate[IIC_SLOW]);
+	mv_twsi_cal_baud_rate(TWSI_BAUD_RATE_FAST, &baud_rate[IIC_FAST]);
+	if (bootverbose)
+		device_printf(dev, "calculated baud rates are:\n"
+		    " %" PRIu32 " kHz (M=%d, N=%d) for slow,\n"
+		    " %" PRIu32 " kHz (M=%d, N=%d) for fast.\n",
+		    baud_rate[IIC_SLOW].raw / 1000,
+		    baud_rate[IIC_SLOW].m,
+		    baud_rate[IIC_SLOW].n,
+		    baud_rate[IIC_FAST].raw / 1000,
+		    baud_rate[IIC_FAST].m,
+		    baud_rate[IIC_FAST].n);
+
+	sc->iicbus = device_add_child(dev, IICBUS_DEVNAME, -1);
+	if (sc->iicbus == NULL) {
+		device_printf(dev, "could not add iicbus child\n");
+		mv_twsi_detach(dev);
+		return (ENXIO);
+	}
+	/* Attach iicbus. */
+	bus_generic_attach(dev);
+
+	iicbusnode = 0;
+	/* Find iicbus as the child devices in the device tree. */
+	for (child = OF_child(ofw_bus_get_node(dev)); child != 0;
+	    child = OF_peer(child)) {
+		len = OF_getproplen(child, "model");
+		if (len <= 0 || len > sizeof(dname))
+			continue;
+		error = OF_getprop(child, "model", &dname, len);
+		if (error == -1)
+			continue;
+		len = strlen(dname);
+		if (len == strlen(IICBUS_DEVNAME) &&
+		    strncasecmp(dname, IICBUS_DEVNAME, len) == 0) {
+			iicbusnode = child;
+			break; 
+		}
+	}
+	if (iicbusnode == 0)
+		goto attach_end;
+
+	/* Attach child devices onto iicbus. */
+	for (child = OF_child(iicbusnode); child != 0; child = OF_peer(child)) {
+		/* Get slave address. */
+		error = OF_getprop(child, "i2c-address", &paddr, sizeof(paddr));
+		if (error == -1)
+			error = OF_getprop(child, "reg", &paddr, sizeof(paddr));
+		if (error == -1)
+			continue;
+
+		/* Get device driver name. */
+		len = OF_getproplen(child, "model");
+		if (len <= 0 || len > sizeof(dname))
+			continue;
+		OF_getprop(child, "model", &dname, len);
+
+		if (bootverbose)
+			device_printf(dev, "adding a device %s at %d.\n",
+			    dname, fdt32_to_cpu(paddr));
+		childdev = BUS_ADD_CHILD(sc->iicbus, 0, dname, -1);
+		devi = IICBUS_IVAR(childdev);
+		devi->addr = fdt32_to_cpu(paddr);
+	}
+
+attach_end:
+	bus_generic_attach(sc->iicbus);
+
+	return (0);
+}
+
+static int
+mv_twsi_detach(device_t dev)
+{
+	struct mv_twsi_softc *sc;
+	int rv;
+
+	sc = device_get_softc(dev);
+
+	if ((rv = bus_generic_detach(dev)) != 0)
+		return (rv);
+
+	if (sc->iicbus != NULL)
+		if ((rv = device_delete_child(dev, sc->iicbus)) != 0)
+			return (rv);
+
+	bus_release_resources(dev, res_spec, sc->res);
+
+	mtx_destroy(&sc->mutex);
+	return (0);
+}
+
+/*
+ * Only slave mode supported, disregard [old]addr
+ */
+static int
+mv_twsi_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
+{
+	struct mv_twsi_softc *sc;
+	uint32_t param;
+
+	sc = device_get_softc(dev);
+
+	switch (speed) {
+	case IIC_SLOW:
+	case IIC_FAST:
+		param = baud_rate[speed].param;
+		break;
+	case IIC_FASTEST:
+	case IIC_UNKNOWN:
+	default:
+		param = baud_rate[IIC_FAST].param;
+		break;
+	}
+
+	mtx_lock(&sc->mutex);
+	TWSI_WRITE(sc, TWSI_SOFT_RESET, 0x0);
+	DELAY(2000);
+	TWSI_WRITE(sc, TWSI_BAUD_RATE, param);
+	TWSI_WRITE(sc, TWSI_CONTROL, TWSI_CONTROL_TWSIEN | TWSI_CONTROL_ACK);
+	DELAY(1000);
+	mtx_unlock(&sc->mutex);
+
+	return (0);
+}
+
+/*
+ * timeout is given in us
+ */
+static int
+mv_twsi_repeated_start(device_t dev, u_char slave, int timeout)
+{
+	struct mv_twsi_softc *sc;
+	int rv;
+
+	sc = device_get_softc(dev);
+
+	mtx_lock(&sc->mutex);
+	rv = twsi_locked_start(dev, sc, TWSI_STATUS_RPTD_START, slave,
+	    timeout);
+	mtx_unlock(&sc->mutex);
+
+	if (rv) {
+		mv_twsi_stop(dev);
+		return (rv);
+	} else
+		return (IIC_NOERR);
+}
+
+/*
+ * timeout is given in us
+ */
+static int
+mv_twsi_start(device_t dev, u_char slave, int timeout)
+{
+	struct mv_twsi_softc *sc;
+	int rv;
+
+	sc = device_get_softc(dev);
+
+	mtx_lock(&sc->mutex);
+	rv = twsi_locked_start(dev, sc, TWSI_STATUS_START, slave, timeout);
+	mtx_unlock(&sc->mutex);
+
+	if (rv) {
+		mv_twsi_stop(dev);
+		return (rv);
+	} else
+		return (IIC_NOERR);
+}
+
+static int
+mv_twsi_stop(device_t dev)
+{
+	struct mv_twsi_softc *sc;
+
+	sc = device_get_softc(dev);
+
+	mtx_lock(&sc->mutex);
+	twsi_control_set(sc, TWSI_CONTROL_STOP);
+	DELAY(1000);
+	twsi_clear_iflg(sc);
+	mtx_unlock(&sc->mutex);
+
+	return (IIC_NOERR);
+}
+
+static int
+mv_twsi_read(device_t dev, char *buf, int len, int *read, int last, int delay)
+{
+	struct mv_twsi_softc *sc;
+	uint32_t status;
+	int last_byte, rv;
+
+	sc = device_get_softc(dev);
+
+	mtx_lock(&sc->mutex);
+	*read = 0;
+	while (*read < len) {
+		/*
+		 * Check if we are reading last byte of the last buffer,
+		 * do not send ACK then, per I2C specs
+		 */
+		last_byte = ((*read == len - 1) && last) ? 1 : 0;
+		if (last_byte)
+			twsi_control_clear(sc, TWSI_CONTROL_ACK);
+		else
+			twsi_control_set(sc, TWSI_CONTROL_ACK);
+
+		DELAY (1000);
+		twsi_clear_iflg(sc);
+
+		if (twsi_poll_ctrl(sc, delay, TWSI_CONTROL_IFLG)) {
+			debugf("timeout reading data\n");
+			rv = IIC_ETIMEOUT;
+			goto out;
+		}
+
+		status = TWSI_READ(sc, TWSI_STATUS);
+		if (status != (last_byte ?
+		    TWSI_STATUS_DATA_RD_NOACK : TWSI_STATUS_DATA_RD_ACK)) {
+			debugf("wrong status (%02x) while reading\n", status);
+			rv = IIC_ESTATUS;
+			goto out;
+		}
+
+		*buf++ = TWSI_READ(sc, TWSI_DATA);
+		(*read)++;
+	}
+	rv = IIC_NOERR;
+out:
+	mtx_unlock(&sc->mutex);
+	return (rv);
+}
+
+static int
+mv_twsi_write(device_t dev, const char *buf, int len, int *sent, int timeout)
+{
+	struct mv_twsi_softc *sc;
+	uint32_t status;
+	int rv;
+
+	sc = device_get_softc(dev);
+
+	mtx_lock(&sc->mutex);
+	*sent = 0;
+	while (*sent < len) {
+		TWSI_WRITE(sc, TWSI_DATA, *buf++);
+
+		twsi_clear_iflg(sc);
+		if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
+			debugf("timeout writing data\n");
+			rv = IIC_ETIMEOUT;
+			goto out;
+		}
+
+		status = TWSI_READ(sc, TWSI_STATUS);
+		if (status != TWSI_STATUS_DATA_WR_ACK) {
+			debugf("wrong status (%02x) while writing\n", status);
+			rv = IIC_ESTATUS;
+			goto out;
+		}
+		(*sent)++;
+	}
+	rv = IIC_NOERR;
+out:
+	mtx_unlock(&sc->mutex);
+	return (rv);
+}



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