[PATCH 4.9 39/78] i2c: rcar: in slave mode, clear NACK earlier

Greg Kroah-Hartman
2020-09-01T15:16:32Z

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

[ 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>
---
drivers/i2c/busses/i2c-rcar.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 4231673435e7b..6be02da2ccc46 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -534,6 +534,7 @@ 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);
}
--
2.25.1