i2c: rcar: in slave mode, clear NACK earlier

[ Upstream commit 914a7b3563b8fb92f976619bbd0fa3a4a708baae ]

Currently, a NACK in slave mode is set/cleared when SCL is held low by
the IP core right before the bit is about to be pushed out. This is too
late for clearing and then a NACK from the previous byte is still used
for the current one. Now, let's clear the NACK right after we detected
the STOP condition following the NACK.

Fixes: de20d1857dd6 ("i2c: rcar: add slave support")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index ddfb08a3e6c20590aadde5c042931163cda86469..00b3178c36a7a68dd776cee18f1a3b53ffc5fa58 100644 (file)
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -393,6 +393,7 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
        /* master sent stop */
        if (ssr_filtered & SSR) {
                i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value);
+               rcar_i2c_write(priv, ICSCR, SIE | SDBS); /* clear our NACK */
                rcar_i2c_write(priv, ICSIER, SAR);
                rcar_i2c_write(priv, ICSSR, ~SSR & 0xff);
        }