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i2c: uniphier-f: fix misdetection of incomplete STOP condition

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Currently, the status register FI2C_SR is checked immediately after
a STOP condition is issued in case of the deferred STOP condition.
It takes typically 5-10 usec until the corresponding bits in the
register are set, so the error check for "stop condition was not
completed" is very likely to be false positive.

Add wait code to relax the status register check.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Masahiro Yamada 2016-09-23 22:34:41 +09:00 committed by Wolfram Sang
parent 6212e1d6ed
commit fcbd4bddb3
1 changed files with 10 additions and 4 deletions
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14
drivers/i2c/busses/i2c-uniphier-f.c
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@ -14,6 +14,7 @@
#include <linux/clk.h>
#include <linux/i2c.h>
#include <linux/iopoll.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
@ -348,14 +349,19 @@ static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
dev_dbg(&adap->dev, "complete\n");
if (unlikely(priv->flags & UNIPHIER_FI2C_DEFER_STOP_COMP)) {
u32 status = readl(priv->membase + UNIPHIER_FI2C_SR);
u32 status;
int ret;
if (!(status & UNIPHIER_FI2C_SR_STS) ||
status & UNIPHIER_FI2C_SR_BB) {
ret = readl_poll_timeout(priv->membase + UNIPHIER_FI2C_SR,
status,
(status & UNIPHIER_FI2C_SR_STS) &&
!(status & UNIPHIER_FI2C_SR_BB),
1, 20);
if (ret) {
dev_err(&adap->dev,
"stop condition was not completed.\n");
uniphier_fi2c_recover(priv);
return -EBUSY;
return ret;
}
}