Sometimes we would get the following flow when doing an i2cset:
0x1 STATUS SLAVE_ACTIVITY=0x1 : RAW_INTR_STAT=0x514 : INTR_STAT=0x4
I2C_SLAVE_WRITE_RECEIVED
0x1 STATUS SLAVE_ACTIVITY=0x0 : RAW_INTR_STAT=0x714 : INTR_STAT=0x204
I2C_SLAVE_WRITE_REQUESTED
I2C_SLAVE_WRITE_RECEIVED
Documentation/i2c/slave-interface.rst says that I2C_SLAVE_WRITE_REQUESTED,
which is mandatory, should be sent while the data did not arrive yet. It
means in a write-request I2C_SLAVE_WRITE_REQUESTED should be reported
before any I2C_SLAVE_WRITE_RECEIVED.
By the way, I2C_SLAVE_STOP didn't be reported in the above case because
DW_IC_INTR_STAT was not 0x200.
dev->status can be used to record the current state, especially Designware
I2C controller has no interrupts to identify a write-request. This patch
makes not only I2C_SLAVE_WRITE_REQUESTED been reported first when
IC_INTR_RX_FULL is rising and dev->status isn't STATUS_WRITE_IN_PROGRESS
but also I2C_SLAVE_STOP been reported when a STOP condition is received.
Signed-off-by: Michael Wu <michael...@vatics.com>
---
drivers/i2c/busses/i2c-designware-slave.c | 45 +++++++++--------------
1 file changed, 18 insertions(+), 27 deletions(-)
diff --git a/drivers/i2c/busses/i2c-designware-slave.c
b/drivers/i2c/busses/i2c-designware-slave.c
index 13de01a0f75f..0d15f4c1e9f7 100644
--- a/drivers/i2c/busses/i2c-designware-slave.c
+++ b/drivers/i2c/busses/i2c-designware-slave.c
@@ -172,26 +172,25 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev
*dev)
"%#x STATUS SLAVE_ACTIVITY=%#x : RAW_INTR_STAT=%#x :
INTR_STAT=%#x\n",
enabled, slave_activity, raw_stat, stat);
- if ((stat & DW_IC_INTR_RX_FULL) && (stat & DW_IC_INTR_STOP_DET))
- i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED, &val);
+ if (stat & DW_IC_INTR_RX_FULL) {
+ if (dev->status != STATUS_WRITE_IN_PROGRESS) {
+ dev->status = STATUS_WRITE_IN_PROGRESS;
+ i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED,
+ &val);
+ }
+
+ regmap_read(dev->map, DW_IC_DATA_CMD, &tmp);
+ val = tmp;
+ if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED,
+ &val))
+ dev_vdbg(dev->dev, "Byte %X acked!", val);
+ }
if (stat & DW_IC_INTR_RD_REQ) {
if (slave_activity) {
- if (stat & DW_IC_INTR_RX_FULL) {
- regmap_read(dev->map, DW_IC_DATA_CMD, &tmp);
- val = tmp;
-
- if (!i2c_slave_event(dev->slave,
- I2C_SLAVE_WRITE_RECEIVED,
- &val)) {
- dev_vdbg(dev->dev, "Byte %X acked!",
- val);
- }
- regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);
- } else {
- regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);
- regmap_read(dev->map, DW_IC_CLR_RX_UNDER, &tmp);
- }
+ regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);
+
+ dev->status = STATUS_READ_IN_PROGRESS;
if (!i2c_slave_event(dev->slave,
I2C_SLAVE_READ_REQUESTED,
&val))
@@ -203,18 +202,10 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev
*dev)
if (!i2c_slave_event(dev->slave, I2C_SLAVE_READ_PROCESSED,
&val))
regmap_read(dev->map, DW_IC_CLR_RX_DONE, &tmp);
-
- i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
- return 1;
}
- if (stat & DW_IC_INTR_RX_FULL) {
- regmap_read(dev->map, DW_IC_DATA_CMD, &tmp);
- val = tmp;
- if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED,
- &val))
- dev_vdbg(dev->dev, "Byte %X acked!", val);
- } else {
+ if (stat & DW_IC_INTR_STOP_DET) {
+ dev->status = STATUS_IDLE;
i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
}
--
2.17.1
