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* [PATCH] pci: dwc: add a check for resetting gpio
@ 2018-12-26  2:22 ` Kangjie Lu
  0 siblings, 0 replies; 4+ messages in thread
From: Kangjie Lu @ 2018-12-26  2:22 UTC (permalink / raw)
  To: kjlu
  Cc: pakki001, Jingoo Han, Lorenzo Pieralisi, Bjorn Helgaas,
	Kukjin Kim, Krzysztof Kozlowski, linux-pci, linux-arm-kernel,
	linux-samsung-soc, linux-kernel

devm_gpio_request_one() could fail. The fix checks its status and issues
an error if it fails.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
 drivers/pci/controller/dwc/pci-exynos.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-exynos.c b/drivers/pci/controller/dwc/pci-exynos.c
index cee5f2f590e2..e3a045e215d2 100644
--- a/drivers/pci/controller/dwc/pci-exynos.c
+++ b/drivers/pci/controller/dwc/pci-exynos.c
@@ -226,9 +226,12 @@ static void exynos_pcie_assert_reset(struct exynos_pcie *ep)
 	struct dw_pcie *pci = ep->pci;
 	struct device *dev = pci->dev;
 
-	if (ep->reset_gpio >= 0)
-		devm_gpio_request_one(dev, ep->reset_gpio,
-				GPIOF_OUT_INIT_HIGH, "RESET");
+	if (ep->reset_gpio >= 0) {
+		if (devm_gpio_request_one(dev, ep->reset_gpio,
+				GPIOF_OUT_INIT_HIGH, "RESET"))
+			dev_err(dev, "Failed requesting reset gpio %d\n",
+					ep->reset_gpio);
+	}
 }
 
 static int exynos_pcie_establish_link(struct exynos_pcie *ep)
-- 
2.17.2 (Apple Git-113)


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* [PATCH] pci: dwc: add a check for resetting gpio
@ 2018-12-26  2:22 ` Kangjie Lu
  0 siblings, 0 replies; 4+ messages in thread
From: Kangjie Lu @ 2018-12-26  2:22 UTC (permalink / raw)
  To: kjlu
  Cc: Lorenzo Pieralisi, Jingoo Han, linux-pci, linux-kernel,
	Krzysztof Kozlowski, linux-samsung-soc, Kukjin Kim, pakki001,
	Bjorn Helgaas, linux-arm-kernel

devm_gpio_request_one() could fail. The fix checks its status and issues
an error if it fails.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
 drivers/pci/controller/dwc/pci-exynos.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-exynos.c b/drivers/pci/controller/dwc/pci-exynos.c
index cee5f2f590e2..e3a045e215d2 100644
--- a/drivers/pci/controller/dwc/pci-exynos.c
+++ b/drivers/pci/controller/dwc/pci-exynos.c
@@ -226,9 +226,12 @@ static void exynos_pcie_assert_reset(struct exynos_pcie *ep)
 	struct dw_pcie *pci = ep->pci;
 	struct device *dev = pci->dev;
 
-	if (ep->reset_gpio >= 0)
-		devm_gpio_request_one(dev, ep->reset_gpio,
-				GPIOF_OUT_INIT_HIGH, "RESET");
+	if (ep->reset_gpio >= 0) {
+		if (devm_gpio_request_one(dev, ep->reset_gpio,
+				GPIOF_OUT_INIT_HIGH, "RESET"))
+			dev_err(dev, "Failed requesting reset gpio %d\n",
+					ep->reset_gpio);
+	}
 }
 
 static int exynos_pcie_establish_link(struct exynos_pcie *ep)
-- 
2.17.2 (Apple Git-113)


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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: [PATCH] pci: dwc: add a check for resetting gpio
  2018-12-26  2:22 ` Kangjie Lu
@ 2018-12-31 20:40   ` Bjorn Helgaas
  -1 siblings, 0 replies; 4+ messages in thread
From: Bjorn Helgaas @ 2018-12-31 20:40 UTC (permalink / raw)
  To: Kangjie Lu
  Cc: Lorenzo Pieralisi, Jingoo Han, linux-pci, linux-kernel,
	Krzysztof Kozlowski, linux-samsung-soc, Kukjin Kim, pakki001,
	linux-arm-kernel

Hi Kangjie,

Thanks for the patch.

On Tue, Dec 25, 2018 at 08:22:36PM -0600, Kangjie Lu wrote:
> devm_gpio_request_one() could fail. The fix checks its status and issues
> an error if it fails.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
>  drivers/pci/controller/dwc/pci-exynos.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-exynos.c b/drivers/pci/controller/dwc/pci-exynos.c
> index cee5f2f590e2..e3a045e215d2 100644
> --- a/drivers/pci/controller/dwc/pci-exynos.c
> +++ b/drivers/pci/controller/dwc/pci-exynos.c
> @@ -226,9 +226,12 @@ static void exynos_pcie_assert_reset(struct exynos_pcie *ep)
>  	struct dw_pcie *pci = ep->pci;
>  	struct device *dev = pci->dev;
>  
> -	if (ep->reset_gpio >= 0)
> -		devm_gpio_request_one(dev, ep->reset_gpio,
> -				GPIOF_OUT_INIT_HIGH, "RESET");
> +	if (ep->reset_gpio >= 0) {
> +		if (devm_gpio_request_one(dev, ep->reset_gpio,
> +				GPIOF_OUT_INIT_HIGH, "RESET"))
> +			dev_err(dev, "Failed requesting reset gpio %d\n",
> +					ep->reset_gpio);
> +	}

Even before your patch, this code doesn't make sense to me.

devm_gpio_request_one() is a setup function and should be called in
the probe path.  The "assert_reset" path should do something like
gpio_set_value().  See other callers, e.g.,

  imx6_pcie_probe()
  histb_pcie_probe()
  mvebu_pcie_parse_port()

I'm skeptical that exynos_pcie_assert_reset() ever worked as intended,
so let's straighten that out before worrying about checking the return
code from devm_gpio_request_one().

The result should be two patches: (1) fix the devm_gpio_request_one()
usage, and (2) check the devm_gpio_request_one() return value.

>  }

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH] pci: dwc: add a check for resetting gpio
@ 2018-12-31 20:40   ` Bjorn Helgaas
  0 siblings, 0 replies; 4+ messages in thread
From: Bjorn Helgaas @ 2018-12-31 20:40 UTC (permalink / raw)
  To: Kangjie Lu
  Cc: linux-samsung-soc, Jingoo Han, pakki001, linux-kernel,
	Krzysztof Kozlowski, Lorenzo Pieralisi, Kukjin Kim, linux-pci,
	linux-arm-kernel

Hi Kangjie,

Thanks for the patch.

On Tue, Dec 25, 2018 at 08:22:36PM -0600, Kangjie Lu wrote:
> devm_gpio_request_one() could fail. The fix checks its status and issues
> an error if it fails.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
>  drivers/pci/controller/dwc/pci-exynos.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-exynos.c b/drivers/pci/controller/dwc/pci-exynos.c
> index cee5f2f590e2..e3a045e215d2 100644
> --- a/drivers/pci/controller/dwc/pci-exynos.c
> +++ b/drivers/pci/controller/dwc/pci-exynos.c
> @@ -226,9 +226,12 @@ static void exynos_pcie_assert_reset(struct exynos_pcie *ep)
>  	struct dw_pcie *pci = ep->pci;
>  	struct device *dev = pci->dev;
>  
> -	if (ep->reset_gpio >= 0)
> -		devm_gpio_request_one(dev, ep->reset_gpio,
> -				GPIOF_OUT_INIT_HIGH, "RESET");
> +	if (ep->reset_gpio >= 0) {
> +		if (devm_gpio_request_one(dev, ep->reset_gpio,
> +				GPIOF_OUT_INIT_HIGH, "RESET"))
> +			dev_err(dev, "Failed requesting reset gpio %d\n",
> +					ep->reset_gpio);
> +	}

Even before your patch, this code doesn't make sense to me.

devm_gpio_request_one() is a setup function and should be called in
the probe path.  The "assert_reset" path should do something like
gpio_set_value().  See other callers, e.g.,

  imx6_pcie_probe()
  histb_pcie_probe()
  mvebu_pcie_parse_port()

I'm skeptical that exynos_pcie_assert_reset() ever worked as intended,
so let's straighten that out before worrying about checking the return
code from devm_gpio_request_one().

The result should be two patches: (1) fix the devm_gpio_request_one()
usage, and (2) check the devm_gpio_request_one() return value.

>  }

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-12-31 20:40 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2018-12-26  2:22 [PATCH] pci: dwc: add a check for resetting gpio Kangjie Lu
2018-12-26  2:22 ` Kangjie Lu
2018-12-31 20:40 ` Bjorn Helgaas
2018-12-31 20:40   ` Bjorn Helgaas

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