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

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

[Michael Wu]

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 <michael.wu@vatics.com>
---

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

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

[Jarkko Nikula]

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