Re: [PATCH v4 3/3] drm/xe/i2c: Keep the i2c controller always enabled

[Heikki Krogerus]

On Wed, Jul 15, 2026 at 08:33:31AM +0200, Raag Jadav wrote:
> > +/* See "Disabling DW_apb_i2c" in the DesignWare DW_abp_i2c databook. */
> > +static void xe_i2c_disable(struct xe_i2c *i2c)
> > +{
> > +	int timeout = 100;
> > +	u32 status;
> > +
> > +	xe_mmio_rmw32(i2c->mmio, I2C_REG(DW_IC_ENABLE), 1, 0);
> 
> Can we use DW_IC_ENABLE_* defines?
> 
> > +	do {
> > +		status = xe_mmio_read32(i2c->mmio, I2C_REG(DW_IC_ENABLE_STATUS));
> > +		if (!(status & 1))
> 
> Ditto for DW_IC_STATUS_*.
> 
> > +			return;
> > +		/* Can't sleep here. */
> > +		udelay(25);
> > +	} while (timeout--);
> > +
> > +	dev_warn(&i2c->adapter->dev, "timeout in disabling adapter\n");
> > +}
> 
> ...
> 
> > @@ -230,7 +260,28 @@ static int xe_i2c_write(void *context, unsigned int reg, unsigned int val)
> >  {
> >  	struct xe_i2c *i2c = context;
> >  
> > -	xe_mmio_write32(i2c->mmio, XE_REG(reg + I2C_MEM_SPACE_OFFSET), val);
> > +	switch (reg) {
> > +	case DW_IC_CON:
> > +	case DW_IC_TAR:
> > +	case DW_IC_SAR:
> > +		/* Disable the controller. */
> > +		xe_i2c_disable(i2c);
> > +
> > +		/* Write the register. */
> > +		xe_mmio_write32(i2c->mmio, I2C_REG(reg), val);
> > +
> > +		/* Enable the controller. */
> > +		xe_mmio_rmw32(i2c->mmio, I2C_REG(DW_IC_ENABLE), 0, 1);
> 
> Ditto.

Yes to all three. I'll fix these.

Thanks,

-- 
heikki