From f0d83679a8d471dc8b646919f70595d6fe8c9606 Mon Sep 17 00:00:00 2001
From: Sebastian Heutling <heutling@who-ing.de>
Date: Wed, 29 Jul 2009 15:04:05 -0700
Subject: [PATCH] eeprom/at25: bugfix "not ready" timeout after write
Under certain circumstances msleep(1) within the loop, which waits for the
EEPROM to be finished, might take longer than the timeout. On the next
loop the status register might now return to be ready and therefore the
loop finishes. The following check now tests if a timeout occurred and if
so returns an error although the device reported it was ready.
This fix replaces testing the occurrence of the timeout by testing the
"not ready" bit in the status register.
Signed-off-by: Sebastian Heutling <heutling@who-ing.de>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/misc/eeprom/at25.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c
index b34cb5f79eea..2e535a0ccd5e 100644
--- a/drivers/misc/eeprom/at25.c
+++ b/drivers/misc/eeprom/at25.c
@@ -173,6 +173,7 @@ at25_ee_write(struct at25_data *at25, const char *buf, loff_t off,
unsigned segment;
unsigned offset = (unsigned) off;
u8 *cp = bounce + 1;
+ int sr;
*cp = AT25_WREN;
status = spi_write(at25->spi, cp, 1);
@@ -214,7 +215,6 @@ at25_ee_write(struct at25_data *at25, const char *buf, loff_t off,
timeout = jiffies + msecs_to_jiffies(EE_TIMEOUT);
retries = 0;
do {
- int sr;
sr = spi_w8r8(at25->spi, AT25_RDSR);
if (sr < 0 || (sr & AT25_SR_nRDY)) {
@@ -228,7 +228,7 @@ at25_ee_write(struct at25_data *at25, const char *buf, loff_t off,
break;
} while (retries++ < 3 || time_before_eq(jiffies, timeout));
- if (time_after(jiffies, timeout)) {
+ if ((sr < 0) || (sr & AT25_SR_nRDY)) {
dev_err(&at25->spi->dev,
"write %d bytes offset %d, "
"timeout after %u msecs\n",