[PATCH] i2c-designware: add OF binding support

[PATCH] i2c-designware: add OF binding support

[Rob Herring]

From: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>

Add of_match_table and DT style i2c registration to designware i2c
driver.

Signed-off-by: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
Cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
Cc: Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>
Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
---
 Documentation/devicetree/bindings/i2c/dw-i2c.txt |   23 ++++++++++++++++++++++
 drivers/i2c/busses/i2c-designware.c              |   13 ++++++++++++
 2 files changed, 36 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/i2c/dw-i2c.txt

diff --git a/Documentation/devicetree/bindings/i2c/dw-i2c.txt b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
new file mode 100644
index 0000000..cbcb404
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
@@ -0,0 +1,23 @@
+* Synopsys DesignWare I2C
+
+Required properties :
+
+ - compatible : should be "snps,designware-i2c"
+ - reg : Offset and length of the register set for the device
+ - interrupts : <IRQ> where IRQ is the interrupt number.
+
+Recommended properties :
+
+ - clock-frequency : desired I2C bus clock frequency in Hz.
+
+Example :
+
+	i2c@f0000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "snps,designware-i2c";
+		reg = <0xf0000 0x1000>;
+		interrupts = <11>;
+		clock-frequency = <400000>;
+	};
+
diff --git a/drivers/i2c/busses/i2c-designware.c b/drivers/i2c/busses/i2c-designware.c
index b7a51c4..2911a49 100644
--- a/drivers/i2c/busses/i2c-designware.c
+++ b/drivers/i2c/busses/i2c-designware.c
@@ -37,6 +37,7 @@
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/slab.h>
+#include <linux/of_i2c.h>
 
 /*
  * Registers offset
@@ -770,12 +771,17 @@ static int __devinit dw_i2c_probe(struct platform_device *pdev)
 	adap->algo = &i2c_dw_algo;
 	adap->dev.parent = &pdev->dev;
 
+#ifdef CONFIG_OF
+	r = i2c_add_adapter(adap);
+#else
 	adap->nr = pdev->id;
 	r = i2c_add_numbered_adapter(adap);
+#endif
 	if (r) {
 		dev_err(&pdev->dev, "failure adding adapter\n");
 		goto err_free_irq;
 	}
+	of_i2c_register_devices(adap);
 
 	return 0;
 
@@ -819,6 +825,12 @@ static int __devexit dw_i2c_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct of_device_id dw_i2c_of_match[] = {
+	{ .compatible = "snps,designware-i2c", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
+
 /* work with hotplug and coldplug */
 MODULE_ALIAS("platform:i2c_designware");
 
@@ -827,6 +839,7 @@ static struct platform_driver dw_i2c_driver = {
 	.driver		= {
 		.name	= "i2c_designware",
 		.owner	= THIS_MODULE,
+		.of_match_table = dw_i2c_of_match,
 	},
 };
 
-- 
1.7.4.1

Re: [PATCH] i2c-designware: add OF binding support

[Grant Likely]

On Wed, Aug 3, 2011 at 9:04 PM, Rob Herring <robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> From: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
>
> Add of_match_table and DT style i2c registration to designware i2c
> driver.
>
> Signed-off-by: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
> Cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
> Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
> Cc: Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>
> Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> ---
>  Documentation/devicetree/bindings/i2c/dw-i2c.txt |   23 ++++++++++++++++++++++
>  drivers/i2c/busses/i2c-designware.c              |   13 ++++++++++++
>  2 files changed, 36 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/i2c/dw-i2c.txt
>
> diff --git a/Documentation/devicetree/bindings/i2c/dw-i2c.txt b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
> new file mode 100644
> index 0000000..cbcb404
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
> @@ -0,0 +1,23 @@
> +* Synopsys DesignWare I2C
> +
> +Required properties :
> +
> + - compatible : should be "snps,designware-i2c"
> + - reg : Offset and length of the register set for the device
> + - interrupts : <IRQ> where IRQ is the interrupt number.
> +
> +Recommended properties :
> +
> + - clock-frequency : desired I2C bus clock frequency in Hz.
> +
> +Example :
> +
> +       i2c@f0000 {
> +               #address-cells = <1>;
> +               #size-cells = <0>;
> +               compatible = "snps,designware-i2c";
> +               reg = <0xf0000 0x1000>;
> +               interrupts = <11>;
> +               clock-frequency = <400000>;
> +       };
> +
> diff --git a/drivers/i2c/busses/i2c-designware.c b/drivers/i2c/busses/i2c-designware.c
> index b7a51c4..2911a49 100644
> --- a/drivers/i2c/busses/i2c-designware.c
> +++ b/drivers/i2c/busses/i2c-designware.c
> @@ -37,6 +37,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/io.h>
>  #include <linux/slab.h>
> +#include <linux/of_i2c.h>
>
>  /*
>  * Registers offset
> @@ -770,12 +771,17 @@ static int __devinit dw_i2c_probe(struct platform_device *pdev)
>        adap->algo = &i2c_dw_algo;
>        adap->dev.parent = &pdev->dev;
>
> +#ifdef CONFIG_OF
> +       r = i2c_add_adapter(adap);
> +#else
>        adap->nr = pdev->id;
>        r = i2c_add_numbered_adapter(adap);
> +#endif

Unnecessary.  i2c_add_numbered_adapter will dynamically assign a bus
number now if nr is -1.

Otherwise, the patch looks good.  You can add the following after
removing the above hunk.  Besides, the way this is changed with an
#ifdef will break non-dt users in the same kernel.  You know better
than to do that!  :-)

Acked-by: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org> (after fixing above problem)

g.

Re: [PATCH] i2c-designware: add OF binding support

[Ben Dooks]

On Wed, Aug 03, 2011 at 03:04:23PM -0500, Rob Herring wrote:
> From: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
> 
> Add of_match_table and DT style i2c registration to designware i2c
> driver.
> 
> Signed-off-by: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
> Cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
> Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
> Cc: Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>
> Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> ---
>  Documentation/devicetree/bindings/i2c/dw-i2c.txt |   23 ++++++++++++++++++++++
>  drivers/i2c/busses/i2c-designware.c              |   13 ++++++++++++
>  2 files changed, 36 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/i2c/dw-i2c.txt
> 
> diff --git a/Documentation/devicetree/bindings/i2c/dw-i2c.txt b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
> new file mode 100644
> index 0000000..cbcb404
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
> @@ -0,0 +1,23 @@
> +* Synopsys DesignWare I2C
> +
> +Required properties :
> +
> + - compatible : should be "snps,designware-i2c"
> + - reg : Offset and length of the register set for the device
> + - interrupts : <IRQ> where IRQ is the interrupt number.
> +
> +Recommended properties :
> +
> + - clock-frequency : desired I2C bus clock frequency in Hz.
> +
> +Example :
> +
> +	i2c@f0000 {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		compatible = "snps,designware-i2c";
> +		reg = <0xf0000 0x1000>;
> +		interrupts = <11>;
> +		clock-frequency = <400000>;
> +	};
> +

looks good to me.

> diff --git a/drivers/i2c/busses/i2c-designware.c b/drivers/i2c/busses/i2c-designware.c
> index b7a51c4..2911a49 100644
> --- a/drivers/i2c/busses/i2c-designware.c
> +++ b/drivers/i2c/busses/i2c-designware.c
> @@ -37,6 +37,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/io.h>
>  #include <linux/slab.h>
> +#include <linux/of_i2c.h>
>  
>  /*
>   * Registers offset
> @@ -770,12 +771,17 @@ static int __devinit dw_i2c_probe(struct platform_device *pdev)
>  	adap->algo = &i2c_dw_algo;
>  	adap->dev.parent = &pdev->dev;
>  
> +#ifdef CONFIG_OF
> +	r = i2c_add_adapter(adap);
> +#else
>  	adap->nr = pdev->id;
>  	r = i2c_add_numbered_adapter(adap);
> +#endif

I would say that doing the #ifdef CONFIG_OF is dangerous here when we
are in a mixed OF/platform enviromnent as we're depending on compile
time selection.

I'm also wondering whether we have an of helper macro which takes
a pdev and gives you an adapter number either given on pdev->id or
-1 for the case when we're using the OF bindings.

It might be worth talking to Grant about setting pdev->id to -1 if we
are using an OF device.

>  	if (r) {
>  		dev_err(&pdev->dev, "failure adding adapter\n");
>  		goto err_free_irq;
>  	}
> +	of_i2c_register_devices(adap);

If we did that, we could add a of_i2c_register_adapter() call which
would take the platform device and then do the of_i2c_register_devices()
and do these steps.

>  	return 0;
>  
> @@ -819,6 +825,12 @@ static int __devexit dw_i2c_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static const struct of_device_id dw_i2c_of_match[] = {
> +	{ .compatible = "snps,designware-i2c", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
> +
>  /* work with hotplug and coldplug */
>  MODULE_ALIAS("platform:i2c_designware");
>  
> @@ -827,6 +839,7 @@ static struct platform_driver dw_i2c_driver = {
>  	.driver		= {
>  		.name	= "i2c_designware",
>  		.owner	= THIS_MODULE,
> +		.of_match_table = dw_i2c_of_match,

If my patch for of_match_ptr() is accepted, it will be needed here
otherwise you will need to do something about remvoing the of table
above if not config of.

-- 
Ben Dooks, ben-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, http://www.fluff.org/ben/

Large Hadron Colada: A large Pina Colada that makes the universe disappear.

Re: [PATCH] i2c-designware: add OF binding support

[Rob Herring]

Ben,

On 08/04/2011 04:12 AM, Ben Dooks wrote:
> On Wed, Aug 03, 2011 at 03:04:23PM -0500, Rob Herring wrote:
>> From: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
>>
>> Add of_match_table and DT style i2c registration to designware i2c
>> driver.
>>
>> Signed-off-by: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
>> Cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
>> Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
>> Cc: Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>
>> Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>> ---
>>  Documentation/devicetree/bindings/i2c/dw-i2c.txt |   23 ++++++++++++++++++++++
>>  drivers/i2c/busses/i2c-designware.c              |   13 ++++++++++++
>>  2 files changed, 36 insertions(+), 0 deletions(-)
>>  create mode 100644 Documentation/devicetree/bindings/i2c/dw-i2c.txt
>>
>> diff --git a/Documentation/devicetree/bindings/i2c/dw-i2c.txt b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
>> new file mode 100644
>> index 0000000..cbcb404
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
>> @@ -0,0 +1,23 @@
>> +* Synopsys DesignWare I2C
>> +
>> +Required properties :
>> +
>> + - compatible : should be "snps,designware-i2c"
>> + - reg : Offset and length of the register set for the device
>> + - interrupts : <IRQ> where IRQ is the interrupt number.
>> +
>> +Recommended properties :
>> +
>> + - clock-frequency : desired I2C bus clock frequency in Hz.
>> +
>> +Example :
>> +
>> +	i2c@f0000 {
>> +		#address-cells = <1>;
>> +		#size-cells = <0>;
>> +		compatible = "snps,designware-i2c";
>> +		reg = <0xf0000 0x1000>;
>> +		interrupts = <11>;
>> +		clock-frequency = <400000>;
>> +	};
>> +
> 
> looks good to me.
> 
>> diff --git a/drivers/i2c/busses/i2c-designware.c b/drivers/i2c/busses/i2c-designware.c
>> index b7a51c4..2911a49 100644
>> --- a/drivers/i2c/busses/i2c-designware.c
>> +++ b/drivers/i2c/busses/i2c-designware.c
>> @@ -37,6 +37,7 @@
>>  #include <linux/platform_device.h>
>>  #include <linux/io.h>
>>  #include <linux/slab.h>
>> +#include <linux/of_i2c.h>
>>  
>>  /*
>>   * Registers offset
>> @@ -770,12 +771,17 @@ static int __devinit dw_i2c_probe(struct platform_device *pdev)
>>  	adap->algo = &i2c_dw_algo;
>>  	adap->dev.parent = &pdev->dev;
>>  
>> +#ifdef CONFIG_OF
>> +	r = i2c_add_adapter(adap);
>> +#else
>>  	adap->nr = pdev->id;
>>  	r = i2c_add_numbered_adapter(adap);
>> +#endif
> 
> I would say that doing the #ifdef CONFIG_OF is dangerous here when we
> are in a mixed OF/platform enviromnent as we're depending on compile
> time selection.
> 
> I'm also wondering whether we have an of helper macro which takes
> a pdev and gives you an adapter number either given on pdev->id or
> -1 for the case when we're using the OF bindings.
> 
> It might be worth talking to Grant about setting pdev->id to -1 if we
> are using an OF device.
> 

As Grant said, that's already done and this hunk is not needed.

>>  	if (r) {
>>  		dev_err(&pdev->dev, "failure adding adapter\n");
>>  		goto err_free_irq;
>>  	}
>> +	of_i2c_register_devices(adap);
> 
> If we did that, we could add a of_i2c_register_adapter() call which
> would take the platform device and then do the of_i2c_register_devices()
> and do these steps.
> 

Better yet, how about putting of_i2c_register_devices into
i2c_register_adapter? Everywhere that calls of_i2c_register_devices is
preceded by a call to i2c_add_numbered_adapter or i2c_add_adapter. It
seems logical to put it with i2c_scan_static_board_info. I'll prepare a
patch to add that and remove all the other callers unless you think
that's a bad idea.

>>  	return 0;
>>  
>> @@ -819,6 +825,12 @@ static int __devexit dw_i2c_remove(struct platform_device *pdev)
>>  	return 0;
>>  }
>>  
>> +static const struct of_device_id dw_i2c_of_match[] = {
>> +	{ .compatible = "snps,designware-i2c", },
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
>> +
>>  /* work with hotplug and coldplug */
>>  MODULE_ALIAS("platform:i2c_designware");
>>  
>> @@ -827,6 +839,7 @@ static struct platform_driver dw_i2c_driver = {
>>  	.driver		= {
>>  		.name	= "i2c_designware",
>>  		.owner	= THIS_MODULE,
>> +		.of_match_table = dw_i2c_of_match,
> 
> If my patch for of_match_ptr() is accepted, it will be needed here
> otherwise you will need to do something about remvoing the of table
> above if not config of.

There's really not much harm with having the table. If you match the
device in the non-DT way, the table is not used. Drivers should never
directly access the table either, but use the helpers to get their data.

Rob

Re: [PATCH] i2c-designware: add OF binding support

[Rob Herring]

On 08/04/2011 10:45 AM, Rob Herring wrote:
> Ben,
> 
> On 08/04/2011 04:12 AM, Ben Dooks wrote:
>> On Wed, Aug 03, 2011 at 03:04:23PM -0500, Rob Herring wrote:
>>> From: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
>>>
>>> Add of_match_table and DT style i2c registration to designware i2c
>>> driver.
>>>
>>> Signed-off-by: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
>>> Cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
>>> Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
>>> Cc: Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>
>>> Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>>> ---
>>>  Documentation/devicetree/bindings/i2c/dw-i2c.txt |   23 ++++++++++++++++++++++
>>>  drivers/i2c/busses/i2c-designware.c              |   13 ++++++++++++
>>>  2 files changed, 36 insertions(+), 0 deletions(-)
>>>  create mode 100644 Documentation/devicetree/bindings/i2c/dw-i2c.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/i2c/dw-i2c.txt b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
>>> new file mode 100644
>>> index 0000000..cbcb404
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
>>> @@ -0,0 +1,23 @@
>>> +* Synopsys DesignWare I2C
>>> +
>>> +Required properties :
>>> +
>>> + - compatible : should be "snps,designware-i2c"
>>> + - reg : Offset and length of the register set for the device
>>> + - interrupts : <IRQ> where IRQ is the interrupt number.
>>> +
>>> +Recommended properties :
>>> +
>>> + - clock-frequency : desired I2C bus clock frequency in Hz.
>>> +
>>> +Example :
>>> +
>>> +	i2c@f0000 {
>>> +		#address-cells = <1>;
>>> +		#size-cells = <0>;
>>> +		compatible = "snps,designware-i2c";
>>> +		reg = <0xf0000 0x1000>;
>>> +		interrupts = <11>;
>>> +		clock-frequency = <400000>;
>>> +	};
>>> +
>>
>> looks good to me.
>>
>>> diff --git a/drivers/i2c/busses/i2c-designware.c b/drivers/i2c/busses/i2c-designware.c
>>> index b7a51c4..2911a49 100644
>>> --- a/drivers/i2c/busses/i2c-designware.c
>>> +++ b/drivers/i2c/busses/i2c-designware.c
>>> @@ -37,6 +37,7 @@
>>>  #include <linux/platform_device.h>
>>>  #include <linux/io.h>
>>>  #include <linux/slab.h>
>>> +#include <linux/of_i2c.h>
>>>  
>>>  /*
>>>   * Registers offset
>>> @@ -770,12 +771,17 @@ static int __devinit dw_i2c_probe(struct platform_device *pdev)
>>>  	adap->algo = &i2c_dw_algo;
>>>  	adap->dev.parent = &pdev->dev;
>>>  
>>> +#ifdef CONFIG_OF
>>> +	r = i2c_add_adapter(adap);
>>> +#else
>>>  	adap->nr = pdev->id;
>>>  	r = i2c_add_numbered_adapter(adap);
>>> +#endif
>>
>> I would say that doing the #ifdef CONFIG_OF is dangerous here when we
>> are in a mixed OF/platform enviromnent as we're depending on compile
>> time selection.
>>
>> I'm also wondering whether we have an of helper macro which takes
>> a pdev and gives you an adapter number either given on pdev->id or
>> -1 for the case when we're using the OF bindings.
>>
>> It might be worth talking to Grant about setting pdev->id to -1 if we
>> are using an OF device.
>>
> 
> As Grant said, that's already done and this hunk is not needed.
> 
>>>  	if (r) {
>>>  		dev_err(&pdev->dev, "failure adding adapter\n");
>>>  		goto err_free_irq;
>>>  	}
>>> +	of_i2c_register_devices(adap);
>>
>> If we did that, we could add a of_i2c_register_adapter() call which
>> would take the platform device and then do the of_i2c_register_devices()
>> and do these steps.
>>
> 
> Better yet, how about putting of_i2c_register_devices into
> i2c_register_adapter? Everywhere that calls of_i2c_register_devices is
> preceded by a call to i2c_add_numbered_adapter or i2c_add_adapter. It
> seems logical to put it with i2c_scan_static_board_info. I'll prepare a
> patch to add that and remove all the other callers unless you think
> that's a bad idea.
> 

Nevermind. That would be undoing this commit:

    of/i2c: Fix module load order issue caused by of_i2c.c

    Commit 959e85f7, "i2c: add OF-style registration and binding" caused a
    module dependency loop where of_i2c.c calls functions in i2c-core, and
    i2c-core calls of_i2c_register_devices() in of_i2c.  This means that
    when i2c support is built as a module when CONFIG_OF is set, then
    neither i2c_core nor of_i2c are able to be loaded.

    This patch fixes the problem by moving the of_i2c_register_devices()
    calls back into the device drivers.  Device drivers already
    specifically request the core code to parse the device tree for
    devices anyway by setting the of_node pointer, so it isn't a big
    deal to also call the registration function.  The drivers just become
    slightly more verbose.

    Signed-off-by: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
    Signed-off-by: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>

Rob

>>>  	return 0;
>>>  
>>> @@ -819,6 +825,12 @@ static int __devexit dw_i2c_remove(struct platform_device *pdev)
>>>  	return 0;
>>>  }
>>>  
>>> +static const struct of_device_id dw_i2c_of_match[] = {
>>> +	{ .compatible = "snps,designware-i2c", },
>>> +	{},
>>> +};
>>> +MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
>>> +
>>>  /* work with hotplug and coldplug */
>>>  MODULE_ALIAS("platform:i2c_designware");
>>>  
>>> @@ -827,6 +839,7 @@ static struct platform_driver dw_i2c_driver = {
>>>  	.driver		= {
>>>  		.name	= "i2c_designware",
>>>  		.owner	= THIS_MODULE,
>>> +		.of_match_table = dw_i2c_of_match,
>>
>> If my patch for of_match_ptr() is accepted, it will be needed here
>> otherwise you will need to do something about remvoing the of table
>> above if not config of.
> 
> There's really not much harm with having the table. If you match the
> device in the non-DT way, the table is not used. Drivers should never
> directly access the table either, but use the helpers to get their data.
> 
> Rob
> 
> 

Re: [PATCH] i2c-designware: add OF binding support

[Grant Likely]

On Thu, Aug 4, 2011 at 10:52 PM, Rob Herring <robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On 08/04/2011 10:45 AM, Rob Herring wrote:
>> Ben,
>>
>> On 08/04/2011 04:12 AM, Ben Dooks wrote:
>>> On Wed, Aug 03, 2011 at 03:04:23PM -0500, Rob Herring wrote:
>>>> From: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
>>>>
>>>> Add of_match_table and DT style i2c registration to designware i2c
>>>> driver.
>>>>
>>>> Signed-off-by: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
>>>> Cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
>>>> Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
>>>> Cc: Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>
>>>> Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>>>> ---
>>>>  Documentation/devicetree/bindings/i2c/dw-i2c.txt |   23 ++++++++++++++++++++++
>>>>  drivers/i2c/busses/i2c-designware.c              |   13 ++++++++++++
>>>>  2 files changed, 36 insertions(+), 0 deletions(-)
>>>>  create mode 100644 Documentation/devicetree/bindings/i2c/dw-i2c.txt
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/i2c/dw-i2c.txt b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
>>>> new file mode 100644
>>>> index 0000000..cbcb404
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/i2c/dw-i2c.txt
>>>> @@ -0,0 +1,23 @@
>>>> +* Synopsys DesignWare I2C
>>>> +
>>>> +Required properties :
>>>> +
>>>> + - compatible : should be "snps,designware-i2c"
>>>> + - reg : Offset and length of the register set for the device
>>>> + - interrupts : <IRQ> where IRQ is the interrupt number.
>>>> +
>>>> +Recommended properties :
>>>> +
>>>> + - clock-frequency : desired I2C bus clock frequency in Hz.
>>>> +
>>>> +Example :
>>>> +
>>>> +   i2c@f0000 {
>>>> +           #address-cells = <1>;
>>>> +           #size-cells = <0>;
>>>> +           compatible = "snps,designware-i2c";
>>>> +           reg = <0xf0000 0x1000>;
>>>> +           interrupts = <11>;
>>>> +           clock-frequency = <400000>;
>>>> +   };
>>>> +
>>>
>>> looks good to me.
>>>
>>>> diff --git a/drivers/i2c/busses/i2c-designware.c b/drivers/i2c/busses/i2c-designware.c
>>>> index b7a51c4..2911a49 100644
>>>> --- a/drivers/i2c/busses/i2c-designware.c
>>>> +++ b/drivers/i2c/busses/i2c-designware.c
>>>> @@ -37,6 +37,7 @@
>>>>  #include <linux/platform_device.h>
>>>>  #include <linux/io.h>
>>>>  #include <linux/slab.h>
>>>> +#include <linux/of_i2c.h>
>>>>
>>>>  /*
>>>>   * Registers offset
>>>> @@ -770,12 +771,17 @@ static int __devinit dw_i2c_probe(struct platform_device *pdev)
>>>>     adap->algo = &i2c_dw_algo;
>>>>     adap->dev.parent = &pdev->dev;
>>>>
>>>> +#ifdef CONFIG_OF
>>>> +   r = i2c_add_adapter(adap);
>>>> +#else
>>>>     adap->nr = pdev->id;
>>>>     r = i2c_add_numbered_adapter(adap);
>>>> +#endif
>>>
>>> I would say that doing the #ifdef CONFIG_OF is dangerous here when we
>>> are in a mixed OF/platform enviromnent as we're depending on compile
>>> time selection.
>>>
>>> I'm also wondering whether we have an of helper macro which takes
>>> a pdev and gives you an adapter number either given on pdev->id or
>>> -1 for the case when we're using the OF bindings.
>>>
>>> It might be worth talking to Grant about setting pdev->id to -1 if we
>>> are using an OF device.
>>>
>>
>> As Grant said, that's already done and this hunk is not needed.
>>
>>>>     if (r) {
>>>>             dev_err(&pdev->dev, "failure adding adapter\n");
>>>>             goto err_free_irq;
>>>>     }
>>>> +   of_i2c_register_devices(adap);
>>>
>>> If we did that, we could add a of_i2c_register_adapter() call which
>>> would take the platform device and then do the of_i2c_register_devices()
>>> and do these steps.
>>>
>>
>> Better yet, how about putting of_i2c_register_devices into
>> i2c_register_adapter? Everywhere that calls of_i2c_register_devices is
>> preceded by a call to i2c_add_numbered_adapter or i2c_add_adapter. It
>> seems logical to put it with i2c_scan_static_board_info. I'll prepare a
>> patch to add that and remove all the other callers unless you think
>> that's a bad idea.
>>
>
> Nevermind. That would be undoing this commit:
>
>    of/i2c: Fix module load order issue caused by of_i2c.c

The other alternative would be to move the i2c dt parsing code into
drivers/i2c.  I'm already planning to do that for spi and gpio dt
parsing code.

g.