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i2c: designware: slave should do WRITE_REQUESTED before WRITE_RECEIVED

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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.wu@vatics.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
This commit is contained in:
Michael Wu 2020-10-30 16:04:20 +08:00 committed by Wolfram Sang
parent 66b92313e2
commit 3b5f7f10ff
1 changed files with 17 additions and 26 deletions
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43
drivers/i2c/busses/i2c-designware-slave.c
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@ -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;
regmap_read(dev->map, DW_IC_CLR_RD_REQ, &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);
}
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);
}