[PATCH v2 0/3] drivers: Add the helper function devm_platform_get_and_ioremap_resource_byname()

[PATCH v2 0/3] drivers: Add the helper function devm_platform_get_and_ioremap_resource_byname()

[Cai Huoqing]

Since provide the helper function devm_platform_ioremap_resource_byname()
which is wrap platform_get_resource_byname() and devm_ioremap_resource().
But sometimes, many drivers still need to use the resource variables obtained
by platform_get_resource(). In these case, provide this helper function
devm_platform_get_and_ioremap_resource_byname().

devm_platform_get_and_ioremap_resource_byname will be used:
 .../platform/sti/c8sectpfe/c8sectpfe-core.c   |  7 ++---
 drivers/pci/controller/pcie-mediatek-gen3.c   |  5 +---


Cai Huoqing (3):
  driver core: platform: Add the helper function
    devm_platform_get_and_ioremap_resource_byname()
  media: sti/c8sectpfe: Make use of the helper function
    devm_platform_get_and_ioremap_resource_byname()
  PCI: mediatek-gen3: Make use of the helper function
    devm_platform_get_and_ioremap_resource_byname()

 drivers/base/platform.c                       | 30 ++++++++++++++++---
 .../platform/sti/c8sectpfe/c8sectpfe-core.c   |  7 ++---
 drivers/pci/controller/pcie-mediatek-gen3.c   |  5 +---
 include/linux/platform_device.h               |  3 ++
 4 files changed, 32 insertions(+), 13 deletions(-)

-- 
2.25.1

[PATCH v2 1/3] driver core: platform: Add the helper function devm_platform_get_and_ioremap_resource_byname()

[Cai Huoqing]

Since provide the helper function devm_platform_ioremap_resource_byname()
which is wrap platform_get_resource_byname() and devm_ioremap_resource().
But sometimes, many drivers still need to use the resource variables
obtained by platform_get_resource(). In these cases, provide this helper
function devm_platform_get_and_ioremap_resource_byname().

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
---
v1->v2: Resend this patch as part of a patch series that uses
	the new function. 

 drivers/base/platform.c         | 30 ++++++++++++++++++++++++++----
 include/linux/platform_device.h |  3 +++
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 652531f67135..34bb581338d9 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -124,6 +124,31 @@ void __iomem *devm_platform_ioremap_resource(struct platform_device *pdev,
 }
 EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource);
 
+/**
+ * devm_platform_get_and_ioremap_resource_byname - call devm_ioremap_resource() for a
+ *						   platform device and get resource
+ *
+ * @pdev: platform device to use both for memory resource lookup as well as
+ *        resource management
+ * @name: name of the resource
+ * @res: optional output parameter to store a pointer to the obtained resource.
+ *
+ * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code
+ * on failure.
+ */
+void __iomem *
+devm_platform_get_and_ioremap_resource_byname(struct platform_device *pdev,
+					      const char *name, struct resource **res)
+{
+	struct resource *r;
+
+	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
+	if (res)
+		*res = r;
+	return devm_ioremap_resource(&pdev->dev, r);
+}
+EXPORT_SYMBOL_GPL(devm_platform_get_and_ioremap_resource_byname);
+
 /**
  * devm_platform_ioremap_resource_byname - call devm_ioremap_resource for
  *					   a platform device, retrieve the
@@ -140,10 +165,7 @@ void __iomem *
 devm_platform_ioremap_resource_byname(struct platform_device *pdev,
 				      const char *name)
 {
-	struct resource *res;
-
-	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
-	return devm_ioremap_resource(&pdev->dev, res);
+	return devm_platform_get_and_ioremap_resource_byname(pdev, name, NULL);
 }
 EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource_byname);
 #endif /* CONFIG_HAS_IOMEM */
diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index 7c96f169d274..50eb1a5b503a 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -66,6 +66,9 @@ extern void __iomem *
 devm_platform_ioremap_resource(struct platform_device *pdev,
 			       unsigned int index);
 extern void __iomem *
+devm_platform_get_and_ioremap_resource_byname(struct platform_device *pdev,
+					      const char *name, struct resource **res);
+extern void __iomem *
 devm_platform_ioremap_resource_byname(struct platform_device *pdev,
 				      const char *name);
 extern int platform_get_irq(struct platform_device *, unsigned int);
-- 
2.25.1

[PATCH v2 2/3] media: sti/c8sectpfe: Make use of the helper function devm_platform_get_and_ioremap_resource_byname()

[Cai Huoqing]

Use the devm_platform_get_and_ioremap_resource_byname() helper
instead of calling platform_get_resource_byname() and
devm_ioremap_resource() separately.

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
---
v1->v2: Use devm_platform_get_and_ioremap_resource_byname()
	instead of devm_platform_ioremap_resource_byname().

 drivers/media/platform/sti/c8sectpfe/c8sectpfe-core.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/media/platform/sti/c8sectpfe/c8sectpfe-core.c b/drivers/media/platform/sti/c8sectpfe/c8sectpfe-core.c
index 02dc78bd7fab..8d57970c196c 100644
--- a/drivers/media/platform/sti/c8sectpfe/c8sectpfe-core.c
+++ b/drivers/media/platform/sti/c8sectpfe/c8sectpfe-core.c
@@ -676,14 +676,11 @@ static int c8sectpfe_probe(struct platform_device *pdev)
 
 	fei->dev = dev;
 
-	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "c8sectpfe");
-	fei->io = devm_ioremap_resource(dev, res);
+	fei->io = devm_platform_get_and_ioremap_resource_byname(pdev, "c8sectpfe", &res);
 	if (IS_ERR(fei->io))
 		return PTR_ERR(fei->io);
 
-	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
-					"c8sectpfe-ram");
-	fei->sram = devm_ioremap_resource(dev, res);
+	fei->sram = devm_platform_get_and_ioremap_resource_byname(pdev, "c8sectpfe-ram", &res);
 	if (IS_ERR(fei->sram))
 		return PTR_ERR(fei->sram);
 
-- 
2.25.1

[PATCH v2 3/3] PCI: mediatek-gen3: Make use of the helper function devm_platform_get_and_ioremap_resource_byname()

[Cai Huoqing]

Use the devm_platform_get_and_ioremap_resource_byname() helper
instead of calling platform_get_resource_byname() and
devm_ioremap_resource() separately.

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
---
v1->v2: Use devm_platform_get_and_ioremap_resource_byname()
	instead of devm_platform_ioremap_resource_byname().

 drivers/pci/controller/pcie-mediatek-gen3.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
index 17c59b0d6978..27009da62ec1 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -715,10 +715,7 @@ static int mtk_pcie_parse_port(struct mtk_pcie_port *port)
 	struct resource *regs;
 	int ret;
 
-	regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac");
-	if (!regs)
-		return -EINVAL;
-	port->base = devm_ioremap_resource(dev, regs);
+	port->base = devm_platform_get_and_ioremap_resource_byname(pdev, "pcie-mac", &regs);
 	if (IS_ERR(port->base)) {
 		dev_err(dev, "failed to map register base\n");
 		return PTR_ERR(port->base);
-- 
2.25.1

Re: [PATCH v2 1/3] driver core: platform: Add the helper function devm_platform_get_and_ioremap_resource_byname()

[Greg KH]

On Thu, Sep 02, 2021 at 02:37:00PM +0800, Cai Huoqing wrote:
> Since provide the helper function devm_platform_ioremap_resource_byname()
> which is wrap platform_get_resource_byname() and devm_ioremap_resource().
> But sometimes, many drivers still need to use the resource variables
> obtained by platform_get_resource(). In these cases, provide this helper
> function devm_platform_get_and_ioremap_resource_byname().
> 
> Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
> ---
> v1->v2: Resend this patch as part of a patch series that uses
> 	the new function. 
> 
>  drivers/base/platform.c         | 30 ++++++++++++++++++++++++++----
>  include/linux/platform_device.h |  3 +++
>  2 files changed, 29 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index 652531f67135..34bb581338d9 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -124,6 +124,31 @@ void __iomem *devm_platform_ioremap_resource(struct platform_device *pdev,
>  }
>  EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource);
>  
> +/**
> + * devm_platform_get_and_ioremap_resource_byname - call devm_ioremap_resource() for a
> + *						   platform device and get resource
> + *
> + * @pdev: platform device to use both for memory resource lookup as well as
> + *        resource management
> + * @name: name of the resource
> + * @res: optional output parameter to store a pointer to the obtained resource.
> + *
> + * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code
> + * on failure.
> + */
> +void __iomem *
> +devm_platform_get_and_ioremap_resource_byname(struct platform_device *pdev,
> +					      const char *name, struct resource **res)
> +{
> +	struct resource *r;
> +
> +	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
> +	if (res)
> +		*res = r;

You forgot to check the return value of this call :(

Which means you did not test this?  Why not?

But step back, _WHY_ is this needed at all?  How deep are we going to
get with the "devm_platform_get_and_do_this_and_that_and_that" type
functions here?

You show 2 users of this call, and they save what, 1-2 lines of code
here?

What is the real need for this?

thanks,

greg k-h

Re: [PATCH v2 1/3] driver core: platform: Add the helper function devm_platform_get_and_ioremap_resource_byname()

[Cai Huoqing]

On 02 Sep 21 08:52:45, Greg KH wrote:
> On Thu, Sep 02, 2021 at 02:37:00PM +0800, Cai Huoqing wrote:
> > Since provide the helper function devm_platform_ioremap_resource_byname()
> > which is wrap platform_get_resource_byname() and devm_ioremap_resource().
> > But sometimes, many drivers still need to use the resource variables
> > obtained by platform_get_resource(). In these cases, provide this helper
> > function devm_platform_get_and_ioremap_resource_byname().
> > 
> > Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
> > ---
> > v1->v2: Resend this patch as part of a patch series that uses
> > 	the new function. 
> > 
> >  drivers/base/platform.c         | 30 ++++++++++++++++++++++++++----
> >  include/linux/platform_device.h |  3 +++
> >  2 files changed, 29 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> > index 652531f67135..34bb581338d9 100644
> > --- a/drivers/base/platform.c
> > +++ b/drivers/base/platform.c
> > @@ -124,6 +124,31 @@ void __iomem *devm_platform_ioremap_resource(struct platform_device *pdev,
> >  }
> >  EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource);
> >  
> > +/**
> > + * devm_platform_get_and_ioremap_resource_byname - call devm_ioremap_resource() for a
> > + *						   platform device and get resource
> > + *
> > + * @pdev: platform device to use both for memory resource lookup as well as
> > + *        resource management
> > + * @name: name of the resource
> > + * @res: optional output parameter to store a pointer to the obtained resource.
> > + *
> > + * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code
> > + * on failure.
> > + */
> > +void __iomem *
> > +devm_platform_get_and_ioremap_resource_byname(struct platform_device *pdev,
> > +					      const char *name, struct resource **res)
> > +{
> > +	struct resource *r;
> > +
> > +	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
> > +	if (res)
> > +		*res = r;
> 
> You forgot to check the return value of this call :(
devm_ioremap_resource wiil check it and print error message, here:
./lib/devres.c:136:__devm_ioremap_resource(

	if (!res || resource_type(res) != IORESOURCE_MEM) {
		dev_err(dev, "invalid resource\n");
		return IOMEM_ERR_PTR(-EINVAL);
> 
> Which means you did not test this?  Why not?
> 
> But step back, _WHY_ is this needed at all?  How deep are we going to
> get with the "devm_platform_get_and_do_this_and_that_and_that" type
> functions here?
  the function name seems too long, how can I rename it:)
> 
> You show 2 users of this call, and they save what, 1-2 lines of code
> here?
> 
> What is the real need for this?
> 
> thanks,
> 
> greg k-h
many thanks for your feedback.

Cai

Re: [PATCH v2 1/3] driver core: platform: Add the helper function devm_platform_get_and_ioremap_resource_byname()

[Greg KH]

On Thu, Sep 02, 2021 at 04:05:39PM +0800, Cai Huoqing wrote:
> On 02 Sep 21 08:52:45, Greg KH wrote:
> > On Thu, Sep 02, 2021 at 02:37:00PM +0800, Cai Huoqing wrote:
> > > Since provide the helper function devm_platform_ioremap_resource_byname()
> > > which is wrap platform_get_resource_byname() and devm_ioremap_resource().
> > > But sometimes, many drivers still need to use the resource variables
> > > obtained by platform_get_resource(). In these cases, provide this helper
> > > function devm_platform_get_and_ioremap_resource_byname().
> > > 
> > > Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
> > > ---
> > > v1->v2: Resend this patch as part of a patch series that uses
> > > 	the new function. 
> > > 
> > >  drivers/base/platform.c         | 30 ++++++++++++++++++++++++++----
> > >  include/linux/platform_device.h |  3 +++
> > >  2 files changed, 29 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> > > index 652531f67135..34bb581338d9 100644
> > > --- a/drivers/base/platform.c
> > > +++ b/drivers/base/platform.c
> > > @@ -124,6 +124,31 @@ void __iomem *devm_platform_ioremap_resource(struct platform_device *pdev,
> > >  }
> > >  EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource);
> > >  
> > > +/**
> > > + * devm_platform_get_and_ioremap_resource_byname - call devm_ioremap_resource() for a
> > > + *						   platform device and get resource
> > > + *
> > > + * @pdev: platform device to use both for memory resource lookup as well as
> > > + *        resource management
> > > + * @name: name of the resource
> > > + * @res: optional output parameter to store a pointer to the obtained resource.
> > > + *
> > > + * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code
> > > + * on failure.
> > > + */
> > > +void __iomem *
> > > +devm_platform_get_and_ioremap_resource_byname(struct platform_device *pdev,
> > > +					      const char *name, struct resource **res)
> > > +{
> > > +	struct resource *r;
> > > +
> > > +	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
> > > +	if (res)
> > > +		*res = r;
> > 
> > You forgot to check the return value of this call :(
> devm_ioremap_resource wiil check it and print error message, here:
> ./lib/devres.c:136:__devm_ioremap_resource(
> 
> 	if (!res || resource_type(res) != IORESOURCE_MEM) {
> 		dev_err(dev, "invalid resource\n");
> 		return IOMEM_ERR_PTR(-EINVAL);

And then you move on and use the resource :(

Please properly test your code.

> > Which means you did not test this?  Why not?
> > 
> > But step back, _WHY_ is this needed at all?  How deep are we going to
> > get with the "devm_platform_get_and_do_this_and_that_and_that" type
> > functions here?
>   the function name seems too long, how can I rename it:)

You have not shown a requirement that this new function is needed at
all.

Why are you making this change?  Why do you want to do this?  What is it
helping out with?

thanks,

greg k-h