2020-10-22 08:33:21

by Michael Wu

Subject: [PATCH v2] i2c: designware: call i2c_dw_read_clear_intrbits_slave() once

If some bits were cleared by i2c_dw_read_clear_intrbits_slave() in
i2c_dw_isr_slave() and not handled immediately, those cleared bits would
not be shown again by later i2c_dw_read_clear_intrbits_slave(). They
therefore were forgotten to be handled.

i2c_dw_read_clear_intrbits_slave() should be called once in an ISR and take
its returned state for all later handlings.

Signed-off-by: Michael Wu <[email protected]>
---

Changes in v2:
- revert moving I2C_SLAVE_WRITE_REQUESTED reporting

drivers/i2c/busses/i2c-designware-slave.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
index 44974b53a626..8eced99b7aeb 100644
--- a/drivers/i2c/busses/i2c-designware-slave.c
+++ b/drivers/i2c/busses/i2c-designware-slave.c
@@ -159,7 +159,6 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
u32 raw_stat, stat, enabled, tmp;
u8 val = 0, slave_activity;

- regmap_read(dev->map, DW_IC_INTR_STAT, &stat);
regmap_read(dev->map, DW_IC_ENABLE, &enabled);
regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &raw_stat);
regmap_read(dev->map, DW_IC_STATUS, &tmp);
@@ -168,6 +167,7 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
if (!enabled || !(raw_stat & ~DW_IC_INTR_ACTIVITY) || !dev->slave)
return 0;

+ stat = i2c_dw_read_clear_intrbits_slave(dev);
dev_dbg(dev->dev,
"%#x STATUS SLAVE_ACTIVITY=%#x : RAW_INTR_STAT=%#x : INTR_STAT=%#x\n",
enabled, slave_activity, raw_stat, stat);
@@ -188,11 +188,9 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
val);
}
regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);
- stat = i2c_dw_read_clear_intrbits_slave(dev);
} else {
regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);
regmap_read(dev->map, DW_IC_CLR_RX_UNDER, &tmp);
- stat = i2c_dw_read_clear_intrbits_slave(dev);
}
if (!i2c_slave_event(dev->slave,
I2C_SLAVE_READ_REQUESTED,
@@ -207,7 +205,6 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
regmap_read(dev->map, DW_IC_CLR_RX_DONE, &tmp);

i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
- stat = i2c_dw_read_clear_intrbits_slave(dev);
return 1;
}

@@ -217,10 +214,8 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED,
&val))
dev_vdbg(dev->dev, "Byte %X acked!", val);
- } else {
+ } else
i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
- stat = i2c_dw_read_clear_intrbits_slave(dev);
- }

return 1;
}
@@ -230,7 +225,6 @@ static irqreturn_t i2c_dw_isr_slave(int this_irq, void *dev_id)
struct dw_i2c_dev *dev = dev_id;
int ret;

- i2c_dw_read_clear_intrbits_slave(dev);
ret = i2c_dw_irq_handler_slave(dev);
if (ret > 0)
complete(&dev->cmd_complete);
--
2.17.1

2020-10-22 17:31:10

by Jarkko Nikula

Subject: Re: [PATCH v2] i2c: designware: call i2c_dw_read_clear_intrbits_slave() once

Hi

On 10/22/20 8:46 AM, Michael Wu wrote:
> @@ -217,10 +214,8 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
> if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED,
> &val))
> dev_vdbg(dev->dev, "Byte %X acked!", val);
> - } else {
> + } else
> i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
> - stat = i2c_dw_read_clear_intrbits_slave(dev);
> - }
>
Minor nit. Please don't remove braces here since the upper part of if
statement has them.

From Documentation/process/coding-style.rst:
"
This does not apply if only one branch of a conditional statement is a
single
statement; in the latter case use braces in both branches:

.. code-block:: c

if (condition) {
do_this();
do_that();
} else {
otherwise();
}
"

Otherwise looks good to me.

Jarkko