[PATCH v2 net-next 0/2] nfc: s3fwrn5: Change I2C interrupt trigger to EDGE_RISING

From: Bongsu Jeon <bongsu.jeon@samsung.com>

For stable Samsung's I2C interrupt handling, I changed the interrupt 
trigger from IRQ_TYPE_LEVEL_HIGH to IRQ_TYPE_EDGE_RISING and removed 
the hard coded interrupt trigger type in the i2c module for the flexible 
control.

1/2 is the changed dt binding for the edge rising trigger.
2/2 is to remove the hard coded interrupt trigger type in the i2c module.

ChangeLog:
 v2:
  2/2
   - remove the hard coded interrupt trigger type.

Bongsu Jeon (2):
  dt-bindings: net: nfc: s3fwrn5: Change I2C interrupt trigger to
    EDGE_RISING
  nfc: s3fwrn5: Remove hard coded interrupt trigger type from the i2c
    module

 .../devicetree/bindings/net/nfc/samsung,s3fwrn5.yaml      | 2 +-
 drivers/nfc/s3fwrn5/i2c.c                                 | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

-- 
2.17.1

From: Bongsu Jeon <bongsu.jeon@samsung.com>

Change interrupt trigger from IRQ_TYPE_LEVEL_HIGH to IRQ_TYPE_EDGE_RISING
 for stable NFC I2C interrupt handling.
Samsung's NFC Firmware sends an i2c frame as below.
1. NFC Firmware sets the GPIO(interrupt pin) high when there is an i2c
 frame to send.
2. If the CPU's I2C master has received the i2c frame, NFC F/W sets the
GPIO low.
NFC driver's i2c interrupt handler would be called in the abnormal case
as the NFC FW task of number 2 is delayed because of other high priority
tasks.
In that case, NFC driver will try to receive the i2c frame but there isn't
 any i2c frame to send in NFC.
It would cause an I2C communication problem. This case would hardly happen.
But, I changed the interrupt as a defense code.
If Driver uses the TRIGGER_RISING instead of the LEVEL trigger,
there would be no problem even if the NFC FW task is delayed.

Signed-off-by: Bongsu Jeon <bongsu.jeon@samsung.com>
---
 Documentation/devicetree/bindings/net/nfc/samsung,s3fwrn5.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/net/nfc/samsung,s3fwrn5.yaml b/Documentation/devicetree/bindings/net/nfc/samsung,s3fwrn5.yaml
index ca3904bf90e0..477066e2b821 100644
--- a/Documentation/devicetree/bindings/net/nfc/samsung,s3fwrn5.yaml
+++ b/Documentation/devicetree/bindings/net/nfc/samsung,s3fwrn5.yaml

@@ -76,7 +76,7 @@ examples:
             reg = <0x27>;
 
             interrupt-parent = <&gpa1>;
-            interrupts = <3 IRQ_TYPE_LEVEL_HIGH>;
+            interrupts = <3 IRQ_TYPE_EDGE_RISING>;
 
             en-gpios = <&gpf1 4 GPIO_ACTIVE_HIGH>;
             wake-gpios = <&gpj0 2 GPIO_ACTIVE_HIGH>;

-- 
2.17.1

From: Bongsu Jeon <bongsu.jeon@samsung.com>

For the flexible control of interrupt trigger type, remove the hard coded
interrupt trigger type in the i2c module. The trigger type will be loaded
 from a dts.

Signed-off-by: Bongsu Jeon <bongsu.jeon@samsung.com>
---
 drivers/nfc/s3fwrn5/i2c.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/nfc/s3fwrn5/i2c.c b/drivers/nfc/s3fwrn5/i2c.c
index e1bdde105f24..42f1f610ac2c 100644
--- a/drivers/nfc/s3fwrn5/i2c.c
+++ b/drivers/nfc/s3fwrn5/i2c.c

@@ -179,6 +179,8 @@ static int s3fwrn5_i2c_probe(struct i2c_client *client,
 				  const struct i2c_device_id *id)
 {
 	struct s3fwrn5_i2c_phy *phy;
+	struct irq_data *irq_data;
+	unsigned long irqflags;
 	int ret;
 
 	phy = devm_kzalloc(&client->dev, sizeof(*phy), GFP_KERNEL);

@@ -212,8 +214,11 @@ static int s3fwrn5_i2c_probe(struct i2c_client *client,
 	if (ret < 0)
 		return ret;
 
+	irq_data = irq_get_irq_data(client->irq);
+	irqflags = irqd_get_trigger_type(irq_data) | IRQF_ONESHOT;
+
 	ret = devm_request_threaded_irq(&client->dev, phy->i2c_dev->irq, NULL,
-		s3fwrn5_i2c_irq_thread_fn, IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+		s3fwrn5_i2c_irq_thread_fn, irqflags,
 		S3FWRN5_I2C_DRIVER_NAME, phy);
 	if (ret)
 		s3fwrn5_remove(phy->common.ndev);

-- 
2.17.1

From: Bongsu Jeon <redacted>
Date: Tue,  8 Dec 2020 23:10:10 +0900

From: Bongsu Jeon <bongsu.jeon@samsung.com>

For stable Samsung's I2C interrupt handling, I changed the interrupt 
trigger from IRQ_TYPE_LEVEL_HIGH to IRQ_TYPE_EDGE_RISING and removed 
the hard coded interrupt trigger type in the i2c module for the flexible 
control.

1/2 is the changed dt binding for the edge rising trigger.
2/2 is to remove the hard coded interrupt trigger type in the i2c module.

ChangeLog:
 v2:
  2/2
   - remove the hard coded interrupt trigger type.

Series applied, thanks.

On Tue, Dec 08, 2020 at 11:10:12PM +0900, Bongsu Jeon wrote:

This patch is wrong and should not be applied. David, please give few
days to review the patches. :)

The irqd_get_trigger_type is not necessary.

I'll send follow ups to correct this.

Best regards,
Krzysztof

+
 	ret = devm_request_threaded_irq(&client->dev, phy->i2c_dev->irq, NULL,
-		s3fwrn5_i2c_irq_thread_fn, IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+		s3fwrn5_i2c_irq_thread_fn, irqflags,
 		S3FWRN5_I2C_DRIVER_NAME, phy);
 	if (ret)
 		s3fwrn5_remove(phy->common.ndev);
-- 
2.17.1