[PATCH v2 0/3] Fix deferred probing in the I2C bus drivers

[PATCH v2 0/3] Fix deferred probing in the I2C bus drivers

[Sergey Shtylyov]

Here are 2 patches against the 'i2c/for-current' branch of Wolfram's 'linux.git' repo.
The affected drivers call platform_get_irq() but override its result in case of error
which prevents the deferred probing from working.

I've dropped the patch fixing the i2c-pca-platform driver as I considered a fallback
to polling better than (not guaranteed to work) deferred probing...

[1/2] i2c: iop3xx: fix deferred probing
[2/2] i2c: synquacer: fix deferred probing

Re: [PATCH v2 0/3] Fix deferred probing in the I2C bus drivers

[Sergey Shtylyov]

The subject should've had v3, not v2, sorry!

[PATCH v3 1/2] i2c: iop3xx: fix deferred probing

[Sergey Shtylyov]

When adding the code to handle platform_get_irq*() errors in the commit
489447380a29 ("[PATCH] handle errors returned by platform_get_irq*()"),
the actual error code was enforced to be -ENXIO in the driver for some
strange reason.  This didn't matter much until the deferred probing was
introduced -- which requires an actual error code to be propagated
upstream from the failure site.

While fixing this, also stop overriding the errors from request_irq() to
-EIO (done since the pre-git era).

Fixes: 489447380a29 ("[PATCH] handle errors returned by platform_get_irq*()")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>

---
Changed in version 2:
- refreshed the patch.

Changed in version 2:
- added an article and a space to the patch description;
- updated domain in the OMP email addresses.

 drivers/i2c/busses/i2c-iop3xx.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

Index: linux/drivers/i2c/busses/i2c-iop3xx.c
===================================================================
--- linux.orig/drivers/i2c/busses/i2c-iop3xx.c
+++ linux/drivers/i2c/busses/i2c-iop3xx.c
@@ -467,16 +467,14 @@ iop3xx_i2c_probe(struct platform_device
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
-		ret = -ENXIO;
+		ret = irq;
 		goto unmap;
 	}
 	ret = request_irq(irq, iop3xx_i2c_irq_handler, 0,
 				pdev->name, adapter_data);
 
-	if (ret) {
-		ret = -EIO;
+	if (ret)
 		goto unmap;
-	}
 
 	memcpy(new_adapter->name, pdev->name, strlen(pdev->name));
 	new_adapter->owner = THIS_MODULE;

[PATCH v2 2/2] i2c: synquacer: fix deferred probing

[Sergey Shtylyov]

The driver overrides the error codes returned by platform_get_irq() to
-ENODEV, so if it returns -EPROBE_DEFER, the driver will fail the probe
permanently instead of the deferred probing. Switch to propagating the
error codes upstream...

Fixes: 0d676a6c4390 ("i2c: add support for Socionext SynQuacer I2C controller")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omprussia.ru>

---
 drivers/i2c/busses/i2c-synquacer.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux/drivers/i2c/busses/i2c-synquacer.c
===================================================================
--- linux.orig/drivers/i2c/busses/i2c-synquacer.c
+++ linux/drivers/i2c/busses/i2c-synquacer.c
@@ -578,7 +578,7 @@ static int synquacer_i2c_probe(struct pl
 
 	i2c->irq = platform_get_irq(pdev, 0);
 	if (i2c->irq < 0)
-		return -ENODEV;
+		return i2c->irq;
 
 	ret = devm_request_irq(&pdev->dev, i2c->irq, synquacer_i2c_isr,
 			       0, dev_name(&pdev->dev), i2c);

Re: [PATCH v2 2/2] i2c: synquacer: fix deferred probing

[Ard Biesheuvel]

On Thu, 12 Aug 2021 at 22:39, Sergey Shtylyov <s.shtylyov@omp.ru> wrote:
>
> The driver overrides the error codes returned by platform_get_irq() to
> -ENODEV, so if it returns -EPROBE_DEFER, the driver will fail the probe
> permanently instead of the deferred probing. Switch to propagating the
> error codes upstream...
>
> Fixes: 0d676a6c4390 ("i2c: add support for Socionext SynQuacer I2C controller")
> Signed-off-by: Sergey Shtylyov <s.shtylyov@omprussia.ru>

Acked-by: Ard Biesheuvel <ardb@kernel.org>

>
> ---
>  drivers/i2c/busses/i2c-synquacer.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux/drivers/i2c/busses/i2c-synquacer.c
> ===================================================================
> --- linux.orig/drivers/i2c/busses/i2c-synquacer.c
> +++ linux/drivers/i2c/busses/i2c-synquacer.c
> @@ -578,7 +578,7 @@ static int synquacer_i2c_probe(struct pl
>
>         i2c->irq = platform_get_irq(pdev, 0);
>         if (i2c->irq < 0)
> -               return -ENODEV;
> +               return i2c->irq;
>
>         ret = devm_request_irq(&pdev->dev, i2c->irq, synquacer_i2c_isr,
>                                0, dev_name(&pdev->dev), i2c);

Re: [PATCH v2 2/2] i2c: synquacer: fix deferred probing

[Wolfram Sang]

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On Thu, Aug 12, 2021 at 11:39:11PM +0300, Sergey Shtylyov wrote:
> The driver overrides the error codes returned by platform_get_irq() to
> -ENODEV, so if it returns -EPROBE_DEFER, the driver will fail the probe
> permanently instead of the deferred probing. Switch to propagating the
> error codes upstream...
> 
> Fixes: 0d676a6c4390 ("i2c: add support for Socionext SynQuacer I2C controller")
> Signed-off-by: Sergey Shtylyov <s.shtylyov@omprussia.ru>
> 

Applied to for-next, thanks!


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Re: [PATCH v3 1/2] i2c: iop3xx: fix deferred probing

[Wolfram Sang]

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On Thu, Aug 12, 2021 at 11:35:09PM +0300, Sergey Shtylyov wrote:
> When adding the code to handle platform_get_irq*() errors in the commit
> 489447380a29 ("[PATCH] handle errors returned by platform_get_irq*()"),
> the actual error code was enforced to be -ENXIO in the driver for some
> strange reason.  This didn't matter much until the deferred probing was
> introduced -- which requires an actual error code to be propagated
> upstream from the failure site.
> 
> While fixing this, also stop overriding the errors from request_irq() to
> -EIO (done since the pre-git era).
> 
> Fixes: 489447380a29 ("[PATCH] handle errors returned by platform_get_irq*()")
> Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
> 

Applied to for-next, thanks!


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