Messages in this thread | | | Date | Thu, 30 Jun 2022 08:03:57 +0200 | Subject | Re: [PATCH] extcon: usbc-tusb320: make sure the state is initialized on probe | From | Peter Rosin <> |
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Hi!
2022-06-29 at 21:54, Chanwoo Choi wrote: > On 22. 6. 23. 20:21, Peter Rosin wrote: >> When the port is connected at boot, there is not necessarily >> an interrupt flagged in the interrupt status register, causing >> the IRQ handler to bail out early without reading the state when >> it is invoked directly from probe. >> >> Add a flag that overrides the interrupt status register and reads >> the state regardless during probe. >> >> Fixes: 06bc4ca115cd ("extcon: Add driver for TI TUSB320") >> Signed-off-by: Peter Rosin <peda@axentia.se> >> --- >> drivers/extcon/extcon-usbc-tusb320.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/extcon/extcon-usbc-tusb320.c b/drivers/extcon/extcon-usbc-tusb320.c >> index 6ba3d89b106d..bd3645ae0d52 100644 >> --- a/drivers/extcon/extcon-usbc-tusb320.c >> +++ b/drivers/extcon/extcon-usbc-tusb320.c >> @@ -55,6 +55,7 @@ struct tusb320_priv { >> struct extcon_dev *edev; >> struct tusb320_ops *ops; >> enum tusb320_attached_state state; >> + bool initialized; >> }; >> >> static const char * const tusb_attached_states[] = { >> @@ -195,7 +196,7 @@ static irqreturn_t tusb320_irq_handler(int irq, void *dev_id) >> return IRQ_NONE; >> } >> >> - if (!(reg & TUSB320_REG9_INTERRUPT_STATUS)) >> + if (priv->initialized && !(reg & TUSB320_REG9_INTERRUPT_STATUS)) >> return IRQ_NONE;
Do not return early if priv->initialized is false. Behave as before if priv->initialized is true.
>> >> state = (reg >> TUSB320_REG9_ATTACHED_STATE_SHIFT) & >> @@ -297,6 +298,8 @@ static int tusb320_extcon_probe(struct i2c_client *client, >> */ >> tusb320_irq_handler(client->irq, priv); >> >> + priv->initialized = true; >> + > > After initializing as 'priv->initialized = true', > tusb320_irq_handler() is not anymore detecting the external connector changes.
Have you tested the patch and observed the trouble you are reporting, or have you simply misread the patch?
> > If external connector is detached after finished kernel boot, > how to change the state of external connector by using extcon_set_state()? >
If you did test this and there actually is a problem, maybe there should be READ_ONCE in the irq handler when checking and WRITE_ONCE when assigning priv->initialized. But if that's really what's going on I'd be surprised when it's a variable that changes *once* before the interrupt has even been requested.
Cheers, Peter
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