On Tue, Aug 25, 2020 at 02:47:51PM -0500, Eddie James wrote:

On 8/25/20 1:38 AM, Joel Stanley wrote:

quoted

On Thu, 20 Aug 2020 at 16:12, Eddie James [off-list ref] wrote:

quoted

Mask the IRQ status to only the bits that the driver checks. This
prevents excessive driver warnings when operating in slave mode
when additional bits are set that the driver doesn't handle.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
  drivers/i2c/busses/i2c-aspeed.c | 1 +
  1 file changed, 1 insertion(+)

diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index 31268074c422..abf40f2af8b4 100644
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c

@@ -604,6 +604,7 @@ static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
         writel(irq_received & ~ASPEED_I2CD_INTR_RX_DONE,
                bus->base + ASPEED_I2C_INTR_STS_REG);
         readl(bus->base + ASPEED_I2C_INTR_STS_REG);
+       irq_received &= 0xf000ffff;
         irq_remaining = irq_received;

This would defeat the check for irq_remaining. I don't think we want to do this.

Can you explain why these bits are being set in slave mode?

No, I don't have any documentation for the bits that are masked off here, so
I don't know why they would get set.

The check for irq_remaining is still useful for detecting that the driver
state machine might be out of sync with what the master is doing.

I have a similar patch in my local tree, and the reason being: AST2600
I2C Controller may set I2CD10[25:24] to report Current Slave Parking
Status (defined in new register I2CS24) even though the new register
mode is off. The 2 bits can be ignored in legacy mode, and Ryan from
ASPEED could confirm it.


Cheers,

Tao