diff options
Diffstat (limited to 'drivers/i2c/designware_i2c.c')
| -rw-r--r-- | drivers/i2c/designware_i2c.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c index e60fd0a4190..c68ff6420b2 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; } } |