[1/1] i2c: ocores: fix polling mode workaround on FU540-C000 SoC

Message ID 1602006796-273724-2-git-send-email-sagar.kadam@sifive.com
State New
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Series
  • fix i2c polling mode workaround for FU540-C000 SoC
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Commit Message

Sagar Shrikant Kadam Oct. 6, 2020, 5:53 p.m.
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@sifive.com>
---
 drivers/i2c/busses/i2c-ocores.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

Comments

Peter Korsgaard Oct. 7, 2020, 11:40 a.m. | #1
>>>>> "Sagar" == Sagar Shrikant Kadam <sagar.kadam@sifive.com> 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@sifive.com>
 > ---
 >  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.

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.

Other than that, it looks OK to me.
Sagar Kadam Oct. 8, 2020, 1:53 p.m. | #2
Hello Peter,

> -----Original Message-----

> From: Peter Korsgaard <jacmet@gmail.com> On Behalf Of Peter Korsgaard

> Sent: Wednesday, October 7, 2020 5:10 PM

> To: Sagar Kadam <sagar.kadam@openfive.com>

> Cc: linux-kernel@vger.kernel.org; linux-riscv@lists.infradead.org; linux-

> i2c@vger.kernel.org; andrew@lunn.ch; Paul Walmsley ( Sifive)

> <paul.walmsley@sifive.com>; palmer@dabbelt.com;

> aou@eecs.berkeley.edu

> Subject: Re: [PATCH 1/1] i2c: ocores: fix polling mode workaround on FU540-

> C000 SoC

> 

> [External Email] Do not click links or attachments unless you recognize the

> sender and know the content is safe

> 

> >>>>> "Sagar" == Sagar Shrikant Kadam <sagar.kadam@sifive.com> 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@sifive.com>

>  > ---

>  >  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
Peter Korsgaard Oct. 8, 2020, 4:05 p.m. | #3
>>>>> "Sagar" == Sagar Kadam <sagar.kadam@openfive.com> writes:


 > Hello Peter,

 >> 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.


Yes, that sounds sensible. Thanks.

-- 
Bye, Peter Korsgaard

Patch

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) {
 		ocores_algorithm.master_xfer = ocores_xfer_polling;
-
-		/*
-		 * Set in OCORES_FLAG_BROKEN_IRQ to enable workaround for
-		 * FU540-C000 SoC in polling mode.
-		 */
-		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;
 	} else {
 		if (irq < 0)
 			return irq;