Hi Tomas, On Fri, Apr 28, 2023 at 12:20:15PM +0200, Tomas Mudrunka wrote: > LM8333 uses gpio interrupt line which is triggered by falling edge. > When button is pressed before driver is loaded, > driver will miss the edge and never respond again. > To fix this we run the interrupt handler after registering IRQ > to clear the interrupt via i2c command. > > Signed-off-by: Tomas Mudrunka <tomas.mudrunka@xxxxxxxxx> > --- > drivers/input/keyboard/lm8333.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/input/keyboard/lm8333.c b/drivers/input/keyboard/lm8333.c > index 7457c3220..9a810ca00 100644 > --- a/drivers/input/keyboard/lm8333.c > +++ b/drivers/input/keyboard/lm8333.c > @@ -184,6 +184,8 @@ static int lm8333_probe(struct i2c_client *client) > if (err) > goto free_mem; > > + lm8333_irq_thread(client->irq, lm8333); Just to clarify, my stance is that this call should go _before_ the handler is registered. Your earlier statement that doing so would steal any pending status from the handler is correct; however, it is a moot point because the handler cannot do anything with that status until the input device has been registered anyway. Any events that come before then are off the table, and this is OK because user space isn't going to start consuming key events until well after this driver has probed anyway. The reason behind my assertion is that as a matter of best practice, you should not have two asynchronous threads that can in theory access the same register. You are correct that the handler would simply return IRQ_NONE in such a race, but it sets a bad precedent and opens room for bugs in case this driver is modified in the future. It also creates one unnecessary I2C read. This is why it is much more common to register the handler _after_ manually accessing read-to-clear registers; the register access remains synchronous. In case you feel I have misunderstood, please let me know. > + > err = input_register_device(input); > if (err) > goto free_irq; > -- > 2.40.0 Kind regards, Jeff LaBundy
