Re: [PATCH] i2c: spacemit: fix detect issue

Aurelien Jarno
2025-11-06T05:34:37Z

Hi,

On 2025-11-06 09:05, Troy Mitchell wrote:
> On Wed, Nov 05, 2025 at 11:44:00PM +0100, Aurelien Jarno wrote:
> > Hi,
> >
> > On 2025-11-03 15:06, Troy Mitchell wrote:
> [...]
> > > if (i2c->status & (SPACEMIT_SR_BED | SPACEMIT_SR_ALD)) {
> > > spacemit_i2c_reset(i2c);
> > > - return -EAGAIN;
> > > + if (i2c->status & SPACEMIT_SR_ALD)
> > > + return -EAGAIN;
> > > }
> >
> > This makes the resulting code, while correct, complex to understand as
> > it is now two really different errors, as you explained well in the
> > commit message.
> >
> > I therefore suggest to organize the code as:
> >
> > /* Arbitration Loss Detected */
> > if (i2c->status & SPACEMIT_SR_ALD) {
> > spacemit_i2c_reset(i2c);
> > return -EAGAIN;
> > }
> >
> > /* Bus Error No ACK/NAK */
> > if (i2c->status & SPACEMIT_SR_BED) {
> > spacemit_i2c_reset(i2c);
> > }
> Thanks. I'll fix it in the next version.
> >
> >
> > > return i2c->status & SPACEMIT_SR_ACKNAK ? -ENXIO : -EIO;
> > > @@ -491,6 +492,8 @@ static int spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg *msgs, in
> > >
> > > spacemit_i2c_init(i2c);
> > >
> > > + spacemit_i2c_clear_int_status(i2c, SPACEMIT_I2C_INT_STATUS_MASK);
> > > +
> >
> > This sounds good to start the transfer with a clean interrupt state. I
> > just wonder if it should be moved to spacemit_i2c_init(), ie where the
> > corresponding interrupts are enabled.
> Uh, We can move it actually. But is it essentail?

For me ensuring that the interrupt status is in a clean state after
enabling the interrupt is part of the initialization. Furthermore if
spacemit_i2c_init() has to be called from another place, it's very
likely that it's also needed to get interrupt status in a clean state.

Regards
Aurelien

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Aurelien Jarno GPG: 4096R/1DDD8C9B
aurelien@aurel32.net http://aurel32.net