diff mbox series

[v3,2/5] i2c:ocores: do not handle IRQ if IF is not set

Message ID 20190208161201.7860-3-federico.vaga@cern.ch
State Superseded
Headers show
Series [v3,1/5] i2c:ocores: stop transfer on timeout | expand

Commit Message

Federico Vaga Feb. 8, 2019, 4:11 p.m. UTC 
If the Interrupt Flag (IF) is not set, we should not handle the IRQ:
- the line can be shared with other devices
- it can be a spurious interrupt

To avoid reading twice the status register, the ocores_process() function
expects it to be read by the caller.

Signed-off-by: Federico Vaga <federico.vaga@cern.ch>
Acked-by: Peter Korsgaard <peter@korsgaard.com>
---
 drivers/i2c/busses/i2c-ocores.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

Comments

Andrew Lunn Feb. 8, 2019, 5 p.m. UTC | #1 
On Fri, Feb 08, 2019 at 05:11:58PM +0100, Federico Vaga wrote:
> If the Interrupt Flag (IF) is not set, we should not handle the IRQ:
> - the line can be shared with other devices
> - it can be a spurious interrupt
> 
> To avoid reading twice the status register, the ocores_process() function
> expects it to be read by the caller.
> 
> Signed-off-by: Federico Vaga <federico.vaga@cern.ch>
> Acked-by: Peter Korsgaard <peter@korsgaard.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
index aa85202..fcc2558 100644
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -143,10 +143,9 @@  static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
 	return i2c->getreg(i2c, reg);
 }
 
-static void ocores_process(struct ocores_i2c *i2c)
+static void ocores_process(struct ocores_i2c *i2c, u8 stat)
 {
 	struct i2c_msg *msg = i2c->msg;
-	u8 stat = oc_getreg(i2c, OCI2C_STATUS);
 	unsigned long flags;
 
 	/*
@@ -223,8 +222,12 @@  out:
 static irqreturn_t ocores_isr(int irq, void *dev_id)
 {
 	struct ocores_i2c *i2c = dev_id;
+	u8 stat = oc_getreg(i2c, OCI2C_STATUS);
+
+	if (!(stat & OCI2C_STAT_IF))
+		return IRQ_NONE;
 
-	ocores_process(i2c);
+	ocores_process(i2c, stat);
 
 	return IRQ_HANDLED;
 }