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iicbb: Fix pause_sbt() arguments order

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It should make pause interval less strict.

While there, add cpu_spinwait() into a tight spin wait loop to burn
less power and let other SMT thread work more.

MFC after:	1 month
This commit is contained in:
Alexander Motin 2023-12-23 18:52:17 -05:00
parent 553ed8e38b
commit a74df3f96e
1 changed files with 3 additions and 1 deletions
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4
sys/dev/iicbus/iicbb.c
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@ -52,6 +52,7 @@
#include <sys/bus.h>
#include <sys/sysctl.h>
#include <sys/uio.h>
#include <machine/cpu.h>
#ifdef FDT
#include <dev/ofw/ofw_bus.h>
@ -254,11 +255,12 @@ iicbb_waitforscl(device_t dev)
do {
if (I2C_GETSCL(dev))
return (0);
cpu_spinwait();
now = sbinuptime();
} while (now < fast_timeout);
do {
I2C_DEBUG(printf("."));
pause_sbt("iicbb-scl-low", SBT_1MS, C_PREL(8), 0);
pause_sbt("iicbb-scl-low", SBT_1MS, 0, C_PREL(2));
if (I2C_GETSCL(dev))
return (0);
now = sbinuptime();