Merge: i2c: designware: add a new bit check for IC_CON control

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/7070

JIRA: https://issues.redhat.com/browse/RHEL-78660

i2c: designware: add a new bit check for IC_CON control

Signed-off-by: John Allen <johnalle@redhat.com>

Approved-by: Tony Camuso <tcamuso@redhat.com>
Approved-by: David Arcari <darcari@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Augusto Caringi <acaringi@redhat.com>

Author: caringi

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

@@ -37,6 +37,7 @@
 #define DW_IC_CON_STOP_DET_IFADDRESSED		BIT(7)
 #define DW_IC_CON_TX_EMPTY_CTRL			BIT(8)
 #define DW_IC_CON_RX_FIFO_FULL_HLD_CTRL		BIT(9)
+#define DW_IC_CON_BUS_CLEAR_CTRL		BIT(11)
 
 #define DW_IC_DATA_CMD_DAT			GENMASK(7, 0)
 

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

@@ -875,6 +875,7 @@ int i2c_dw_probe_master(struct dw_i2c_dev *dev)
 {
 	struct i2c_adapter *adap = &dev->adapter;
 	unsigned long irq_flags;
+	unsigned int ic_con;
 	int ret;
 
 	init_completion(&dev->cmd_complete);
@@ -895,6 +896,25 @@ int i2c_dw_probe_master(struct dw_i2c_dev *dev)
 	if (ret)
 		return ret;
 
+	/* Lock the bus for accessing DW_IC_CON */
+	ret = i2c_dw_acquire_lock(dev);
+	if (ret)
+		return ret;
+
+	/*
+	 * On AMD platforms BIOS advertises the bus clear feature
+	 * and enables the SCL/SDA stuck low. SMU FW does the
+	 * bus recovery process. Driver should not ignore this BIOS
+	 * advertisement of bus clear feature.
+	 */
+	ret = regmap_read(dev->map, DW_IC_CON, &ic_con);
+	i2c_dw_release_lock(dev);
+	if (ret)
+		return ret;
+
+	if (ic_con & DW_IC_CON_BUS_CLEAR_CTRL)
+		dev->master_cfg |= DW_IC_CON_BUS_CLEAR_CTRL;
+
 	ret = dev->init(dev);
 	if (ret)
 		return ret;