[PATCH] i2c: rcar: slave: only send STOP event when we have been addressed

[PATCH] i2c: rcar: slave: only send STOP event when we have been addressed

[Wolfram Sang]

When the SSR interrupt is activated, it will detect every STOP condition
on the bus, not only the ones after we have been addressed. So, enable
this interrupt only after we have been addressed, and disable it
otherwise.

Fixes: de20d1857dd6 ("i2c: rcar: add slave support")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/i2c/busses/i2c-rcar.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index a45c4bf1ec01..c2921e1d8c4c 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -583,13 +583,14 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
 			rcar_i2c_write(priv, ICSIER, SDR | SSR | SAR);
 		}
 
-		rcar_i2c_write(priv, ICSSR, ~SAR & 0xff);
+		/* Clear SSR, too, because of old STOPs to other clients than us */
+		rcar_i2c_write(priv, ICSSR, ~(SAR | SSR) & 0xff);
 	}
 
 	/* master sent stop */
 	if (ssr_filtered & SSR) {
 		i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value);
-		rcar_i2c_write(priv, ICSIER, SAR | SSR);
+		rcar_i2c_write(priv, ICSIER, SAR);
 		rcar_i2c_write(priv, ICSSR, ~SSR & 0xff);
 	}
 
@@ -853,7 +854,7 @@ static int rcar_reg_slave(struct i2c_client *slave)
 	priv->slave = slave;
 	rcar_i2c_write(priv, ICSAR, slave->addr);
 	rcar_i2c_write(priv, ICSSR, 0);
-	rcar_i2c_write(priv, ICSIER, SAR | SSR);
+	rcar_i2c_write(priv, ICSIER, SAR);
 	rcar_i2c_write(priv, ICSCR, SIE | SDBS);
 
 	return 0;
-- 
2.20.1

Re: [PATCH] i2c: rcar: slave: only send STOP event when we have been addressed

[Wolfram Sang]

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On Mon, Jun 29, 2020 at 05:38:07PM +0200, Wolfram Sang wrote:
> When the SSR interrupt is activated, it will detect every STOP condition
> on the bus, not only the ones after we have been addressed. So, enable
> this interrupt only after we have been addressed, and disable it
> otherwise.
> 
> Fixes: de20d1857dd6 ("i2c: rcar: add slave support")
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Applied to for-next, thanks!


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