- Calculate the I2C baud rate to keep them <100 kHz under different TCLK
frequencies. The maximum freqency is 100 kHz according to the datasheet. - Add child device probing support based on the device tree. It now tries to find i2c-address property in the tree and attach the device with given slave address to iicbus.
This commit is contained in:
parent
f8e8af9cf2
commit
8bfdf49b97
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=239508
@ -47,6 +47,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/module.h>
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#include <sys/resource.h>
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#include <machine/_inttypes.h>
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#include <machine/bus.h>
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#include <machine/resource.h>
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@ -57,12 +58,17 @@ __FBSDID("$FreeBSD$");
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#include <dev/iicbus/iiconf.h>
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#include <dev/iicbus/iicbus.h>
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#include <dev/fdt/fdt_common.h>
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#include <dev/ofw/ofw_bus.h>
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#include <dev/ofw/ofw_bus_subr.h>
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#include <arm/mv/mvreg.h>
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#include <arm/mv/mvvar.h>
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#include "iicbus_if.h"
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#define MV_TWSI_NAME "twsi"
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#define IICBUS_DEVNAME "iicbus"
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#define TWSI_SLAVE_ADDR 0x00
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#define TWSI_EXT_SLAVE_ADDR 0x10
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@ -86,10 +92,10 @@ __FBSDID("$FreeBSD$");
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#define TWSI_STATUS_DATA_RD_NOACK 0x58
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#define TWSI_BAUD_RATE 0x0c
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#define TWSI_BAUD_RATE_94DOT3 0x53 /* N=3, M=10 */
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#define TWSI_BAUD_RATE_74DOT1 0x6b /* N=3, M=13 */
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#define TWSI_BAUD_RATE_51DOT8 0x4c /* N=4, M=9 */
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#define TWSI_BAUD_RATE_99DOT7 0x66 /* N=6, M=12 */
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#define TWSI_BAUD_RATE_PARAM(M,N) ((((M) << 3) | ((N) & 0x7)) & 0x7f)
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#define TWSI_BAUD_RATE_RAW(C,M,N) ((C)/((10*(M+1))<<(N+1)))
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#define TWSI_BAUD_RATE_SLOW 50000 /* 50kHz */
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#define TWSI_BAUD_RATE_FAST 100000 /* 100kHz */
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#define TWSI_SOFT_RESET 0x1c
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@ -109,6 +115,13 @@ struct mv_twsi_softc {
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device_t iicbus;
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};
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static struct mv_twsi_baud_rate {
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uint32_t raw;
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int param;
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int m;
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int n;
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} baud_rate[IIC_FASTEST + 1];
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static int mv_twsi_probe(device_t);
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static int mv_twsi_attach(device_t);
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static int mv_twsi_detach(device_t);
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@ -299,13 +312,49 @@ mv_twsi_probe(device_t dev)
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return (BUS_PROBE_DEFAULT);
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}
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#define ABSSUB(a,b) (((a) > (b)) ? (a) - (b) : (b) - (a))
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static void
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mv_twsi_cal_baud_rate(const uint32_t target, struct mv_twsi_baud_rate *rate)
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{
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uint32_t clk, cur, diff, diff0;
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int m, n, m0, n0;
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/* Calculate baud rate. */
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m0 = n0 = 4; /* Default values on reset */
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diff0 = 0xffffffff;
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clk = get_tclk();
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for (n = 0; n < 8; n++) {
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for (m = 0; m < 16; m++) {
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cur = TWSI_BAUD_RATE_RAW(clk,m,n);
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diff = ABSSUB(target, cur);
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if (diff < diff0) {
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m0 = m;
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n0 = n;
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diff0 = diff;
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}
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}
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}
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rate->raw = TWSI_BAUD_RATE_RAW(clk, m0, n0);
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rate->param = TWSI_BAUD_RATE_PARAM(m0, n0);
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rate->m = m0;
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rate->n = n0;
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}
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static int
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mv_twsi_attach(device_t dev)
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{
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struct mv_twsi_softc *sc;
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phandle_t child, iicbusnode;
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device_t childdev;
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struct iicbus_ivar *devi;
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char dname[32]; /* 32 is taken from struct u_device */
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uint32_t paddr;
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int len, error;
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sc = device_get_softc(dev);
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sc->dev = dev;
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bzero(baud_rate, sizeof(baud_rate));
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mtx_init(&sc->mutex, device_get_nameunit(dev), MV_TWSI_NAME, MTX_DEF);
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@ -316,14 +365,76 @@ mv_twsi_attach(device_t dev)
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return (ENXIO);
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}
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sc->iicbus = device_add_child(dev, "iicbus", -1);
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mv_twsi_cal_baud_rate(TWSI_BAUD_RATE_SLOW, &baud_rate[IIC_SLOW]);
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mv_twsi_cal_baud_rate(TWSI_BAUD_RATE_FAST, &baud_rate[IIC_FAST]);
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if (bootverbose)
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device_printf(dev, "calculated baud rates are:\n"
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" %" PRIu32 " kHz (M=%d, N=%d) for slow,\n"
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" %" PRIu32 " kHz (M=%d, N=%d) for fast.\n",
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baud_rate[IIC_SLOW].raw / 1000,
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baud_rate[IIC_SLOW].m,
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baud_rate[IIC_SLOW].n,
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baud_rate[IIC_FAST].raw / 1000,
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baud_rate[IIC_FAST].m,
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baud_rate[IIC_FAST].n);
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sc->iicbus = device_add_child(dev, IICBUS_DEVNAME, -1);
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if (sc->iicbus == NULL) {
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device_printf(dev, "could not add iicbus child\n");
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mv_twsi_detach(dev);
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return (ENXIO);
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}
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/* Attach iicbus. */
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bus_generic_attach(dev);
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iicbusnode = 0;
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/* Find iicbus as the child devices in the device tree. */
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for (child = OF_child(ofw_bus_get_node(dev)); child != 0;
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child = OF_peer(child)) {
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len = OF_getproplen(child, "model");
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if (len <= 0 || len > sizeof(dname) - 1)
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continue;
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error = OF_getprop(child, "model", &dname, len);
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dname[len + 1] = '\0';
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if (error == -1)
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continue;
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len = strlen(dname);
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if (len == strlen(IICBUS_DEVNAME) &&
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strncasecmp(dname, IICBUS_DEVNAME, len) == 0) {
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iicbusnode = child;
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break;
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}
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}
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if (iicbusnode == 0)
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goto attach_end;
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/* Attach child devices onto iicbus. */
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for (child = OF_child(iicbusnode); child != 0; child = OF_peer(child)) {
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/* Get slave address. */
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error = OF_getprop(child, "i2c-address", &paddr, sizeof(paddr));
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if (error == -1)
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error = OF_getprop(child, "reg", &paddr, sizeof(paddr));
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if (error == -1)
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continue;
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/* Get device driver name. */
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len = OF_getproplen(child, "model");
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if (len <= 0 || len > sizeof(dname) - 1)
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continue;
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OF_getprop(child, "model", &dname, len);
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dname[len + 1] = '\0';
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if (bootverbose)
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device_printf(dev, "adding a device %s at %d.\n",
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dname, fdt32_to_cpu(paddr));
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childdev = BUS_ADD_CHILD(sc->iicbus, 0, dname, -1);
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devi = IICBUS_IVAR(childdev);
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devi->addr = fdt32_to_cpu(paddr);
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}
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attach_end:
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bus_generic_attach(sc->iicbus);
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return (0);
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}
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@ -355,28 +466,26 @@ static int
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mv_twsi_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
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{
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struct mv_twsi_softc *sc;
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uint32_t baud_rate;
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uint32_t param;
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sc = device_get_softc(dev);
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switch (speed) {
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case IIC_SLOW:
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baud_rate = TWSI_BAUD_RATE_51DOT8;
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break;
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case IIC_FAST:
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baud_rate = TWSI_BAUD_RATE_51DOT8;
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param = baud_rate[speed].param;
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break;
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case IIC_UNKNOWN:
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case IIC_FASTEST:
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case IIC_UNKNOWN:
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default:
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baud_rate = TWSI_BAUD_RATE_99DOT7;
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param = baud_rate[IIC_FAST].param;
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break;
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}
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mtx_lock(&sc->mutex);
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TWSI_WRITE(sc, TWSI_SOFT_RESET, 0x0);
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DELAY(2000);
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TWSI_WRITE(sc, TWSI_BAUD_RATE, baud_rate);
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TWSI_WRITE(sc, TWSI_BAUD_RATE, param);
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TWSI_WRITE(sc, TWSI_CONTROL, TWSI_CONTROL_TWSIEN | TWSI_CONTROL_ACK);
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DELAY(1000);
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mtx_unlock(&sc->mutex);
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