Re: [PATCH v6 3/3] drm/xe/i2c: Keep the i2c controller always enabled
Heikki Krogerus <[email protected]> Thu, 30 Jul 2026 13:03:43 +0200
| Newsgroups | org.freedesktop.lists.intel-xe,org.kernel.vger.linux-kernel,org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
On Wed, Jul 29, 2026 at 05:34:26PM +0200, Raag Jadav wrote:
> On Wed, Jul 22, 2026 at 03:35:54PM +0200, Heikki Krogerus wrote:
> > Some platforms make an assumption that the i2c controller's
> > enabled state indicates also the power state of the
> > controller. This can create a problem when the controller is
> > in disabled state, because the hardware may assume
> > incorrectly that it is then also in low-power state.
> >
> > To fix this, the controller is kept enabled by taking over
> > the IC_ENABLE register. The controller has to be disabled
> > when the configuration is updated and when the target
> > address or the slave address are assigned, so disabling it
> > when IC_CON, IC_TAR or IC_SAR registers are programmed, and
> > then re-enabling it again.
> >
> > Fixes: f0e53aadd702 ("drm/xe: Support for I2C attached MCUs")
> > Cc: [email protected]
> > Signed-off-by: Heikki Krogerus <[email protected]>
>
> I'll rely on Andy and Mika's disposition on this one.
Mika should be back from vacation.
--
heikki