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-rw-r--r--drivers/i2c/designware_i2c.c23
1 files changed, 17 insertions, 6 deletions
diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c
index e60fd0a..c68ff64 100644
--- a/drivers/i2c/designware_i2c.c
+++ b/drivers/i2c/designware_i2c.c
@@ -249,6 +249,7 @@ static int __dw_i2c_read(struct i2c_regs *i2c_base, u8 dev, uint addr,
int alen, u8 *buffer, int len)
{
unsigned long start_time_rx;
+ unsigned int active = 0;
#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
/*
@@ -274,18 +275,28 @@ static int __dw_i2c_read(struct i2c_regs *i2c_base, u8 dev, uint addr,
start_time_rx = get_timer(0);
while (len) {
- if (len == 1)
- writel(IC_CMD | IC_STOP, &i2c_base->ic_cmd_data);
- else
- writel(IC_CMD, &i2c_base->ic_cmd_data);
+ if (!active) {
+ /*
+ * Avoid writing to ic_cmd_data multiple times
+ * in case this loop spins too quickly and the
+ * ic_status RFNE bit isn't set after the first
+ * write. Subsequent writes to ic_cmd_data can
+ * trigger spurious i2c transfer.
+ */
+ if (len == 1)
+ writel(IC_CMD | IC_STOP, &i2c_base->ic_cmd_data);
+ else
+ writel(IC_CMD, &i2c_base->ic_cmd_data);
+ active = 1;
+ }
if (readl(&i2c_base->ic_status) & IC_STATUS_RFNE) {
*buffer++ = (uchar)readl(&i2c_base->ic_cmd_data);
len--;
start_time_rx = get_timer(0);
-
+ active = 0;
} else if (get_timer(start_time_rx) > I2C_BYTE_TO) {
- return 1;
+ return 1;
}
}