From: Ryo Kataoka <ryo.kataoka.wt@xxxxxxxxxxx>
Even if R-Car I2C received NACK, after that it might receive ACK
by HW auto restart. In case of that, driver would continue process.
If R-Car I2C didn't receive ACK, the driver would detect timeout
and would report NACK as -ENXIO.
Signed-off-by: Ryo Kataoka <ryo.kataoka.wt@xxxxxxxxxxx>
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@xxxxxxxxx>
---
This patch is based on i2c/for-next branch of Wolfram Sang's linux tree.
drivers/i2c/busses/i2c-rcar.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 71a6e07..dde8abf 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -455,14 +455,20 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
if (msr & MNR) {
/* go to stop phase */
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
- rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP);
rcar_i2c_flags_set(priv, ID_NACK);
goto out;
}
/* Stop */
if (msr & MST) {
- rcar_i2c_flags_set(priv, ID_DONE);
+ if (rcar_i2c_flags_has(priv, ID_NACK)) {
+ /* don't set ID_DONE for expecting ACK
+ after auto-restart by HW */
+ rcar_i2c_write(priv, ICMSR, ~MST);
+ } else {
+ rcar_i2c_flags_set(priv, ID_DONE);
+ rcar_i2c_write(priv, ICMSR, 0);
+ }
goto out;
}
@@ -536,15 +542,14 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
rcar_i2c_flags_has(priv, ID_DONE),
5 * HZ);
if (!timeout) {
+ if (rcar_i2c_flags_has(priv, ID_NACK)) {
+ ret = -ENXIO;
+ break;
+ }
ret = -ETIMEDOUT;
break;
}
- if (rcar_i2c_flags_has(priv, ID_NACK)) {
- ret = -ENXIO;
- break;
- }
-
if (rcar_i2c_flags_has(priv, ID_ARBLOST)) {
ret = -EAGAIN;
break;
--
1.9.1
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