Patch "i2c: designware: call i2c_dw_read_clear_intrbits_slave() once" has been added to the 5.9-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    i2c: designware: call i2c_dw_read_clear_intrbits_slave() once

to the 5.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     i2c-designware-call-i2c_dw_read_clear_intrbits_slave.patch
and it can be found in the queue-5.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit ee2c868f29ea65c901b0e0e7caa1fcc9e7bf8d1f
Author: Michael Wu <michael.wu@xxxxxxxxxx>
Date:   Fri Oct 30 16:04:19 2020 +0800

    i2c: designware: call i2c_dw_read_clear_intrbits_slave() once
    
    [ Upstream commit 66b92313e2ca9208b5f3ebf5d86e9a818299d8fa ]
    
    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@xxxxxxxxxx>
    Acked-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>
    Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
index 44974b53a6268..13de01a0f75f0 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;
 	}
 
@@ -219,7 +216,6 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
 			dev_vdbg(dev->dev, "Byte %X acked!", val);
 	} else {
 		i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
-		stat = i2c_dw_read_clear_intrbits_slave(dev);
 	}
 
 	return 1;
@@ -230,7 +226,6 @@ 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);