diff mbox series

[V6,4/7] OF: properties: Implement get_match_data() callback

Message ID 1512493493-6464-5-git-send-email-okaya@codeaurora.org
State Not Applicable, archived
Headers show
Series dmaengine: qcom_hidma: add support for bugfixed HW | expand

Commit Message

Sinan Kaya Dec. 5, 2017, 5:04 p.m. UTC
Now that we have a get_match_data() callback as part of the firmware node,
implement the OF specific piece for it.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/of/property.c | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

Rob Herring Dec. 5, 2017, 9:21 p.m. UTC | #1
On Tue, Dec 5, 2017 at 11:04 AM, Sinan Kaya <okaya@codeaurora.org> wrote:
> Now that we have a get_match_data() callback as part of the firmware node,
> implement the OF specific piece for it.
>
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
>  drivers/of/property.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/drivers/of/property.c b/drivers/of/property.c
> index 264c355..9964169 100644
> --- a/drivers/of/property.c
> +++ b/drivers/of/property.c
> @@ -981,6 +981,12 @@ static int of_fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,
>         return 0;
>  }
>
> +void *of_fwnode_get_match_data(const struct fwnode_handle *fwnode,

Should be static. With that, for patches 3 and 4:

Reviewed-by: Rob Herring <robh@kernel.org>

> +                              struct device *dev)
> +{
> +       return (void *)of_device_get_match_data(dev);
> +}
> +
>  const struct fwnode_operations of_fwnode_ops = {
>         .get = of_fwnode_get,
>         .put = of_fwnode_put,
> @@ -996,5 +1002,6 @@ static int of_fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,
>         .graph_get_remote_endpoint = of_fwnode_graph_get_remote_endpoint,
>         .graph_get_port_parent = of_fwnode_graph_get_port_parent,
>         .graph_parse_endpoint = of_fwnode_graph_parse_endpoint,
> +       .get_match_data = of_fwnode_get_match_data,
>  };
>  EXPORT_SYMBOL_GPL(of_fwnode_ops);
> --
> 1.9.1
>
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Sakari Ailus Dec. 7, 2017, 12:38 p.m. UTC | #2
Hi Sinan,

On Tue, Dec 05, 2017 at 12:04:49PM -0500, Sinan Kaya wrote:
> Now that we have a get_match_data() callback as part of the firmware node,
> implement the OF specific piece for it.
> 
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
>  drivers/of/property.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/of/property.c b/drivers/of/property.c
> index 264c355..9964169 100644
> --- a/drivers/of/property.c
> +++ b/drivers/of/property.c
> @@ -981,6 +981,12 @@ static int of_fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,
>  	return 0;
>  }
>  
> +void *of_fwnode_get_match_data(const struct fwnode_handle *fwnode,
> +			       struct device *dev)

static, as Rob mentioned.

> +{
> +	return (void *)of_device_get_match_data(dev);
> +}
> +
>  const struct fwnode_operations of_fwnode_ops = {
>  	.get = of_fwnode_get,
>  	.put = of_fwnode_put,
> @@ -996,5 +1002,6 @@ static int of_fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,
>  	.graph_get_remote_endpoint = of_fwnode_graph_get_remote_endpoint,
>  	.graph_get_port_parent = of_fwnode_graph_get_port_parent,
>  	.graph_parse_endpoint = of_fwnode_graph_parse_endpoint,
> +	.get_match_data = of_fwnode_get_match_data,

Please arrange right after device_is_available, the same applies to the
ACPI equivalent (5th patch).

>  };
>  EXPORT_SYMBOL_GPL(of_fwnode_ops);

With the above changes plus the ones in my comments on 3rd patch, on
patches 3--5:

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Lothar Waßmann Dec. 7, 2017, 1:10 p.m. UTC | #3
Hi,

On Tue,  5 Dec 2017 12:04:49 -0500 Sinan Kaya wrote:
> Now that we have a get_match_data() callback as part of the firmware node,
> implement the OF specific piece for it.
> 
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
>  drivers/of/property.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/of/property.c b/drivers/of/property.c
> index 264c355..9964169 100644
> --- a/drivers/of/property.c
> +++ b/drivers/of/property.c
> @@ -981,6 +981,12 @@ static int of_fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,
>  	return 0;
>  }
>  
> +void *of_fwnode_get_match_data(const struct fwnode_handle *fwnode,
> +			       struct device *dev)
Shouldn't this be 'const void *of_fwnode_get_match_data'



Lothar Waßmann
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Sinan Kaya Dec. 7, 2017, 2:45 p.m. UTC | #4
On 12/7/2017 8:10 AM, Lothar Waßmann wrote:
>> +void *of_fwnode_get_match_data(const struct fwnode_handle *fwnode,
>> +			       struct device *dev)
> Shouldn't this be 'const void *of_fwnode_get_match_data

OF keeps the driver data as a (const void*) internally. ACPI keeps the
driver data as kernel_ulong_t in struct acpi_device_id.

I tried to find the middle ground here by converting output to void*
but not keeping const.
Lothar Waßmann Dec. 7, 2017, 3:20 p.m. UTC | #5
Hi,

On Thu, 7 Dec 2017 09:45:31 -0500 Sinan Kaya wrote:
> On 12/7/2017 8:10 AM, Lothar Waßmann wrote:
> >> +void *of_fwnode_get_match_data(const struct fwnode_handle *fwnode,
> >> +			       struct device *dev)
> > Shouldn't this be 'const void *of_fwnode_get_match_data
> 
> OF keeps the driver data as a (const void*) internally. ACPI keeps the
> driver data as kernel_ulong_t in struct acpi_device_id.
> 
> I tried to find the middle ground here by converting output to void*
> but not keeping const.
> 
It should be no problem to cast a (const void *) to an unsigned long
data type (without const qualifier).


Lothar Waßmann
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Sinan Kaya Dec. 7, 2017, 5:50 p.m. UTC | #6
On 12/7/2017 10:20 AM, Lothar Waßmann wrote:
> Hi,
> 
> On Thu, 7 Dec 2017 09:45:31 -0500 Sinan Kaya wrote:
>> On 12/7/2017 8:10 AM, Lothar Waßmann wrote:
>>>> +void *of_fwnode_get_match_data(const struct fwnode_handle *fwnode,
>>>> +			       struct device *dev)
>>> Shouldn't this be 'const void *of_fwnode_get_match_data
>>
>> OF keeps the driver data as a (const void*) internally. ACPI keeps the
>> driver data as kernel_ulong_t in struct acpi_device_id.
>>
>> I tried to find the middle ground here by converting output to void*
>> but not keeping const.
>>
> It should be no problem to cast a (const void *) to an unsigned long
> data type (without const qualifier).
> 

It is the other way around. If I change this API to return a a (const void*),
the device_get_match_data() function need to return a (const void *).

While implementing the ACPI piece, I have to convert an unsigned long to
(const void *) in ACPI code so that the APIs are compatible.

> 
> Lothar Waßmann
>
Lothar Waßmann Dec. 8, 2017, 8:09 a.m. UTC | #7
Hi,

On Thu, 7 Dec 2017 12:50:50 -0500 Sinan Kaya wrote:
> On 12/7/2017 10:20 AM, Lothar Waßmann wrote:
> > Hi,
> > 
> > On Thu, 7 Dec 2017 09:45:31 -0500 Sinan Kaya wrote:
> >> On 12/7/2017 8:10 AM, Lothar Waßmann wrote:
> >>>> +void *of_fwnode_get_match_data(const struct fwnode_handle *fwnode,
> >>>> +			       struct device *dev)
> >>> Shouldn't this be 'const void *of_fwnode_get_match_data
> >>
> >> OF keeps the driver data as a (const void*) internally. ACPI keeps the
> >> driver data as kernel_ulong_t in struct acpi_device_id.
> >>
> >> I tried to find the middle ground here by converting output to void*
> >> but not keeping const.
> >>
> > It should be no problem to cast a (const void *) to an unsigned long
> > data type (without const qualifier).
> > 
> 
> It is the other way around. If I change this API to return a a (const void*),
> the device_get_match_data() function need to return a (const void *).
> 
> While implementing the ACPI piece, I have to convert an unsigned long to
> (const void *) in ACPI code so that the APIs are compatible.
> 
That's true, but I don't see any problem with that. Your
device_get_match_data() is merely a wrapper around of_device_get_match_data()
which returns a const pointer. I see no reason to change this to a
non-const pointer by the wrapper function.


Lothar Waßmann
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Lothar Waßmann Dec. 8, 2017, 9:11 a.m. UTC | #8
Hi,

On Thu, 7 Dec 2017 12:50:50 -0500 Sinan Kaya wrote:
> On 12/7/2017 10:20 AM, Lothar Waßmann wrote:
> > Hi,
> > 
> > On Thu, 7 Dec 2017 09:45:31 -0500 Sinan Kaya wrote:
> >> On 12/7/2017 8:10 AM, Lothar Waßmann wrote:
> >>>> +void *of_fwnode_get_match_data(const struct fwnode_handle *fwnode,
> >>>> +			       struct device *dev)
> >>> Shouldn't this be 'const void *of_fwnode_get_match_data
> >>
> >> OF keeps the driver data as a (const void*) internally. ACPI keeps the
> >> driver data as kernel_ulong_t in struct acpi_device_id.
> >>
> >> I tried to find the middle ground here by converting output to void*
> >> but not keeping const.
> >>
> > It should be no problem to cast a (const void *) to an unsigned long
> > data type (without const qualifier).
> > 
> 
> It is the other way around. If I change this API to return a a (const void*),
> the device_get_match_data() function need to return a (const void *).
> 
> While implementing the ACPI piece, I have to convert an unsigned long to
> (const void *) in ACPI code so that the APIs are compatible.
> 
Just one more remark: Do you need write access to the data the pointer
returned by device_get_match_data() or of_fwnode_get_match_data()
points to?
If not, the return type of those functions should be 'const void *'.


Lothar Waßmann
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Sinan Kaya Dec. 8, 2017, 2:33 p.m. UTC | #9
On 12/8/2017 4:11 AM, Lothar Waßmann wrote:
>> While implementing the ACPI piece, I have to convert an unsigned long to
>> (const void *) in ACPI code so that the APIs are compatible.
>>
> Just one more remark: Do you need write access to the data the pointer
> returned by device_get_match_data() or of_fwnode_get_match_data()
> points to?
> If not, the return type of those functions should be 'const void *'.

Yes, the only reason driver is trying to obtain this data pointer is to modify
members of it. I did a quick test with your suggestion.

test.c: In function ‘main’:
test.c:15:2: error: assignment of member ‘m’ in read-only object
  t->m = 3;
  ^

struct test
{
        int m;
};

int main(void)
{
        const void *ptr;
        unsigned long l =4;
        const struct test *t;

        ptr = (const void *)l;

        t = ptr;
        t->m = 3;
}
Sinan Kaya Dec. 8, 2017, 2:40 p.m. UTC | #10
On 12/8/2017 9:33 AM, Sinan Kaya wrote:
> On 12/8/2017 4:11 AM, Lothar Waßmann wrote:
>>> While implementing the ACPI piece, I have to convert an unsigned long to
>>> (const void *) in ACPI code so that the APIs are compatible.
>>>
>> Just one more remark: Do you need write access to the data the pointer
>> returned by device_get_match_data() or of_fwnode_get_match_data()
>> points to?
>> If not, the return type of those functions should be 'const void *'.
> 
> Yes, the only reason driver is trying to obtain this data pointer is to modify
> members of it. I did a quick test with your suggestion.

I guess I should soften my statement here. I look at examples, they seem to be read.
Even for my HIDMA case:

static const struct of_device_id hidma_match[] = {
	{.compatible = "qcom,hidma-1.0",},
	{.compatible = "qcom,hidma-1.1", .data = (void *)(HIDMA_MSI_CAP),},
	{.compatible = "qcom,hidma-1.2",
	 .data = (void *)(HIDMA_MSI_CAP | HIDMA_IDENTITY_CAP),},
	{},
}; 

I can change the return type to (const void*) if Rob, Rafael and Sakari agrees.
I didn't really like converting a long to const void*. That's my personal opinion.

> 
> test.c: In function ‘main’:
> test.c:15:2: error: assignment of member ‘m’ in read-only object
>   t->m = 3;
>   ^
> 
> struct test
> {
>         int m;
> };
> 
> int main(void)
> {
>         const void *ptr;
>         unsigned long l =4;
>         const struct test *t;
> 
>         ptr = (const void *)l;
> 
>         t = ptr;
>         t->m = 3;
> }
> 
> 
>
diff mbox series

Patch

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 264c355..9964169 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -981,6 +981,12 @@  static int of_fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,
 	return 0;
 }
 
+void *of_fwnode_get_match_data(const struct fwnode_handle *fwnode,
+			       struct device *dev)
+{
+	return (void *)of_device_get_match_data(dev);
+}
+
 const struct fwnode_operations of_fwnode_ops = {
 	.get = of_fwnode_get,
 	.put = of_fwnode_put,
@@ -996,5 +1002,6 @@  static int of_fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,
 	.graph_get_remote_endpoint = of_fwnode_graph_get_remote_endpoint,
 	.graph_get_port_parent = of_fwnode_graph_get_port_parent,
 	.graph_parse_endpoint = of_fwnode_graph_parse_endpoint,
+	.get_match_data = of_fwnode_get_match_data,
 };
 EXPORT_SYMBOL_GPL(of_fwnode_ops);