[PATCH v5 4/6] i2c: npcm: Modify the client address assignment
From: Tyrone Ting
Date: Tue Oct 01 2024 - 02:30:59 EST
From: Tyrone Ting <kfting@xxxxxxxxxxx>
Store the client address earlier since it might get called in
the i2c_recover_bus() logic flow at the early stage of
npcm_i2c_master_xfer().
Signed-off-by: Tyrone Ting <kfting@xxxxxxxxxxx>
Reviewed-by: Tali Perry <tali.perry1@xxxxxxxxx>
---
drivers/i2c/busses/i2c-npcm7xx.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 03d6c8702ecf..0ee77e1fbc08 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2155,6 +2155,19 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
} while (time_is_after_jiffies(time_left) && bus_busy);
+ /*
+ * Previously, the address was stored w/o left-shift by one bit and
+ * with that shift in the following call to npcm_i2c_master_start_xmit().
+ *
+ * Since there are cases that the i2c_recover_bus() gets called at the
+ * early stage of npcm_i2c_master_xfer(), the address is stored with
+ * the shift and used in the i2c_recover_bus().
+ *
+ * The address is stored from bit 1 to bit 7 in the register for
+ * sending the i2c address later so it's left-shifted by 1 bit.
+ */
+ bus->dest_addr = slave_addr << 1;
+
/*
* Check the BER (bus error) state, when ber_state is true, it means that the module
* detects the bus error which is caused by some factor like that the electricity
@@ -2172,7 +2185,6 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
}
npcm_i2c_init_params(bus);
- bus->dest_addr = slave_addr;
bus->msgs = msgs;
bus->msgs_num = num;
bus->cmd_err = 0;
--
2.34.1