On Tue, Jun 23, 2026 at 04:39:05PM +0200, Raag Jadav wrote:
> On Mon, Jun 22, 2026 at 01:47:59PM +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.
>
> ...
>
> > static int xe_i2c_read(void *context, unsigned int reg, unsigned int *val)
> > {
> > struct xe_i2c *i2c = context;
> >
> > - *val = xe_mmio_read32(i2c->mmio, XE_REG(reg + I2C_MEM_SPACE_OFFSET));
> > + switch (reg) {
>
> Curious, should I expect DW_IC_INTR_MASK case here which skips the MMIO?
Probable not. We have the ACCESS_POLLING flag set, so the
i2c-designware will only write 0 to that register. Check
__i2c_dw_write_intr_mask().
Thanks,
--
heikki
