i2c: designware: do not hold SCL low when I2C_DYNAMIC_TAR_UPDATE is not set

When the Tx FIFO is empty and the last command has no STOP bit
set, the master holds SCL low. If I2C_DYNAMIC_TAR_UPDATE is not
set, BIT(13) MST_ON_HOLD of IC_RAW_INTR_STAT is not enabled,
causing the __i2c_dw_disable() timeout. This is quite similar to
commit 2409205 ("i2c: designware: fix __i2c_dw_disable() in
case master is holding SCL low"). Also check BIT(7)
MST_HOLD_TX_FIFO_EMPTY in IC_STATUS, which is available when
IC_STAT_FOR_CLK_STRETCH is set.

Fixes: 2409205 ("i2c: designware: fix __i2c_dw_disable() in case master is holding SCL low")
Co-developed-by: Xiaowu Ding <[email protected]>
Signed-off-by: Xiaowu Ding <[email protected]>
Co-developed-by: Angus Chen <[email protected]>
Signed-off-by: Angus Chen <[email protected]>
Signed-off-by: Liu Peibao <[email protected]>
Acked-by: Jarkko Nikula <[email protected]>
Signed-off-by: Andi Shyti <[email protected]>

Author: Liu Peibao

drivers/i2c/busses/i2c-designware-common.c

@@ -524,17 +524,19 @@ int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev)
 void __i2c_dw_disable(struct dw_i2c_dev *dev)
 {
 	struct i2c_timings *t = &dev->timings;
-	unsigned int raw_intr_stats;
+	unsigned int raw_intr_stats, ic_stats;
 	unsigned int enable;
 	int timeout = 100;
 	bool abort_needed;
 	unsigned int status;
 	int ret;
 
 	regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &raw_intr_stats);
+	regmap_read(dev->map, DW_IC_STATUS, &ic_stats);
 	regmap_read(dev->map, DW_IC_ENABLE, &enable);
 
-	abort_needed = raw_intr_stats & DW_IC_INTR_MST_ON_HOLD;
+	abort_needed = (raw_intr_stats & DW_IC_INTR_MST_ON_HOLD) ||
+			(ic_stats & DW_IC_STATUS_MASTER_HOLD_TX_FIFO_EMPTY);
 	if (abort_needed) {
 		if (!(enable & DW_IC_ENABLE_ENABLE)) {
 			regmap_write(dev->map, DW_IC_ENABLE, DW_IC_ENABLE_ENABLE);

drivers/i2c/busses/i2c-designware-core.h

@@ -116,6 +116,7 @@
 #define DW_IC_STATUS_RFNE			BIT(3)
 #define DW_IC_STATUS_MASTER_ACTIVITY		BIT(5)
 #define DW_IC_STATUS_SLAVE_ACTIVITY		BIT(6)
+#define DW_IC_STATUS_MASTER_HOLD_TX_FIFO_EMPTY	BIT(7)
 
 #define DW_IC_SDA_HOLD_RX_SHIFT			16
 #define DW_IC_SDA_HOLD_RX_MASK			GENMASK(23, 16)