[PATCH v5 6/6] i2c: npcm: Enable slave in eob interrupt

Tyrone Ting posted 6 patches 1 month, 4 weeks ago
There is a newer version of this series
[PATCH v5 6/6] i2c: npcm: Enable slave in eob interrupt
Posted by Tyrone Ting 1 month, 4 weeks ago
From: Charles Boyer <Charles.Boyer@fii-usa.com>

Nuvoton slave enable was in user space API call master_xfer, so it is
subject to delays from the OS scheduler. If the BMC is not enabled for
slave mode in time for master to send response, then it will NAK the
address match. Then the PLDM request timeout occurs.

If the slave enable is moved to the EOB interrupt service routine, then
the BMC can be ready in slave mode by the time it needs to receive a
response.

Signed-off-by: Charles Boyer <Charles.Boyer@fii-usa.com>
Signed-off-by: Vivekanand Veeracholan <vveerach@google.com>
Signed-off-by: Tyrone Ting <kfting@nuvoton.com>
Reviewed-by: Tali Perry <tali.perry1@gmail.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 2ed69e92edf6..90a6e6842c6b 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -1925,6 +1925,12 @@ static int npcm_i2c_int_master_handler(struct npcm_i2c *bus)
 	    (FIELD_GET(NPCM_I2CCST3_EO_BUSY,
 		       ioread8(bus->reg + NPCM_I2CCST3)))) {
 		npcm_i2c_irq_handle_eob(bus);
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+		/* reenable slave if it was enabled */
+		if (bus->slave)
+			iowrite8((bus->slave->addr & 0x7F) | NPCM_I2CADDR_SAEN,
+				 bus->reg + NPCM_I2CADDR1);
+#endif
 		return 0;
 	}
 
-- 
2.34.1