Quoting Dmitry Torokhov (2021-06-02 21:33:41) > On Wed, Jun 02, 2021 at 06:33:49PM -0700, Stephen Boyd wrote: > > Quoting Dmitry Torokhov (2021-06-02 18:18:17) > > > > > > I do not think keeping counter balanced would be important here, as we > > > are shutting down, and upon reboot everything will be reinitialized from > > > scratch. Also, we are lucky in that there is just a handful of I2C > > > drivers defining shutdown() methods. > > > > > > > Please don't make me shave this yak. > > > > > > I'm afraid someone has to... I'm adding Wolfram to CC to get his take on > > > this. > > > > > > > I suppose another option would be to introduce some common function that > > i2c drivers can use for their shutdown op, like i2c_generic_shutdown() > > that would disable the irq? I would guess that it isn't a great idea to > > blanket disable the irq in case some i2c driver wants to do something > > that may require that irq to come in once more during shutdown to signal > > that things are off or something like that. > > > > Would having this common function that this driver opts into work for > > you? > > Opting in in this fashion will still require changes in the majority > of drivers (any I2C touchscreen or touchpad may be touched while system > is being shut down, so all of them will need to have interrupt freed or > disabled, or they may initiate I2C transfer). How about something like > this; Yes, this approach should work. I assume a device that doesn't have a shutdown function will be happy to let the i2c core disable the irq for it so it looks low risk. Will you send a proper patch to Wolfram or would you like me to wrap it up and resend? > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c > index 38107c0c318c..c835e7bb71de 100644 > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -603,9 +603,12 @@ static void i2c_device_shutdown(struct device *dev) > > if (!client || !dev->driver) > return; > + > driver = to_i2c_driver(dev->driver); > if (driver->shutdown) > driver->shutdown(client); > + else if (client->irq > 0) > + disable_irq(client->irq); > } > > static void i2c_client_dev_release(struct device *dev) >
