Hello Peter,
> -----Original Message-----
> From: Peter Korsgaard <jacmet@xxxxxxxxx> On Behalf Of Peter Korsgaard
> Sent: Wednesday, October 7, 2020 5:10 PM
> To: Sagar Kadam <sagar.kadam@xxxxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-riscv@xxxxxxxxxxxxxxxxxxx; linux-
> i2c@xxxxxxxxxxxxxxx; andrew@xxxxxxx; Paul Walmsley ( Sifive)
> <paul.walmsley@xxxxxxxxxx>; palmer@xxxxxxxxxxx;
> aou@xxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH 1/1] i2c: ocores: fix polling mode workaround on FU540-
> C000 SoC
>
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>
> >>>>> "Sagar" == Sagar Shrikant Kadam <sagar.kadam@xxxxxxxxxx> writes:
>
> > The FU540-C000 has a broken IRQ and support was added earlier
> > so that it will operate in polling mode, but seems to work only
> > in case interrupts property is missing from the i2c0 dt-node.
> > This should not be the case and the driver should handle polling
> > mode with the interrupt property present in i2c0 node of the
> > device tree.
> > So check if it's the FU540-C000 soc and enable polling mode master
> > xfers, as the IRQ for this chip is broken.
>
> > Fixes commit c45d4ba86731 ("i2c: ocores: add polling mode workaround
> > for Sifive FU540-C000 SoC")
>
> > Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@xxxxxxxxxx>
> > ---
> > drivers/i2c/busses/i2c-ocores.c | 22 +++++++++++++---------
> > 1 file changed, 13 insertions(+), 9 deletions(-)
>
> > diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-
> ocores.c
> > index f5fc75b..4405244 100644
> > --- a/drivers/i2c/busses/i2c-ocores.c
> > +++ b/drivers/i2c/busses/i2c-ocores.c
> > @@ -686,17 +686,21 @@ static int ocores_i2c_probe(struct
> platform_device *pdev)
>
> > init_waitqueue_head(&i2c->wait);
>
> > + /*
> > + * Set OCORES_FLAG_BROKEN_IRQ to enable workaround for
> > + * FU540-C000 SoC in polling mode.
> > + * Since the SoC does have interrupt it's dt has the interrupt
> > + * defined but it should be bypassed in driver as this SoC has
> > + * a broken IRQ, hence update the master_xfer to use polling
> > + * transfers.
> > + */
> > + match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
> > + if (match && (long)match->data == TYPE_SIFIVE_REV0)
> > + i2c->flags |= OCORES_FLAG_BROKEN_IRQ;
> > +
> > irq = platform_get_irq(pdev, 0);
> > - if (irq == -ENXIO) {
> > + if (i2c->flags == OCORES_FLAG_BROKEN_IRQ || irq == -ENXIO) {
>
> NIT: flags is a bitmask, so i2c->flags & OCORES_FLAG_BROKEN_IRQ would be
> better, even if there currently doesn't exist any other flags.
>
Thanks for your suggestions. I will apply the bitmask, this will be better.
> TYPE_SIFIVE_REV0 is also set for two compatibles:
>
> {
> .compatible = "sifive,fu540-c000-i2c",
> .data = (void *)TYPE_SIFIVE_REV0,
> },
> {
> .compatible = "sifive,i2c0",
> .data = (void *)TYPE_SIFIVE_REV0,
> },
>
> Are both affected by this issue? if not, we will need to extend the code
> to handle them differently.
>
No, this issue is present in FU540-C000 SoC i.e SoC- specific, and so I can check
for the soc-compatible string as follows:
- match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
- if (match && (long)match->data == TYPE_SIFIVE_REV0)
+ if (of_device_is_compatible(pdev->dev.of_node,
+ "sifive,fu540-c000-i2c"))
Please let me know if this is okay.
Thanks & BR,
Sagar
> Other than that, it looks OK to me.
>
> --
> Bye, Peter Korsgaard
