[PATCH 0/3] i2c: Relax requirement for I2C Device ID tables

[PATCH 0/3] i2c: Relax requirement for I2C Device ID tables

[Lee Jones]

Hi Wolfram,

After this patch-set, it should become possible to start stripping out
those unnecessary I2C Device ID tables that are currently lurking around,
mostly redundantly.  Firstly, we create a look-up function whose job it
is to match I2C device name to a Device Tree node.  Then we add some
extra protection in i2c_match_id(), so that we can call the function with
a NULL parameter. This in turn aids to the elegance of the final change
which relaxes the requirement of a populated .id_table.

Kind regards,
Lee

[PATCH 1/3] i2c: Provide 'device type' to 'OF device node' look-up

[Lee Jones]

We have a problem.  There are lots of I2C device ID tables scattered
around the kernel which are redundant in all Device Tree and/or ACPI
only supported device drivers.  After recent discussions it has become
apparent that the only thing blocking the complete removal of these
tables is the continued support of 'register an I2C device via sysfs'
functionality.  As the sysfs method doesn't know anything about Device
Tree or ACPI, we can not pass any nodes in.  This patch searches all
known Device Tree nodes and attempts to acquire a match from the
device name provided via sysfs.  It can not fail, but if found assigns
the matching of_node to i2c_board_info prior to registering.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/i2c/i2c-core.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 7c7f4b8..2e47641 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -64,6 +64,7 @@ static DEFINE_IDR(i2c_adapter_idr);
 
 static struct device_type i2c_client_type;
 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
+static struct device_node *of_i2c_type_to_node(char *type);
 
 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
 
@@ -863,6 +864,8 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 		return -EINVAL;
 	}
 
+	info.of_node = of_i2c_type_to_node(info.type);
+
 	client = i2c_new_device(adap, &info);
 	if (!client)
 		return -EINVAL;
@@ -1088,8 +1091,36 @@ struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
 	return i2c_verify_adapter(dev);
 }
 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
+
+static struct device_node *of_i2c_type_to_node(char *type)
+{
+	struct device_node *np;
+	const char *compatible, *name;
+	int len;
+
+	if (!type)
+		return NULL;
+
+	for_each_of_allnodes(np) {
+		compatible = of_get_property(np, "compatible", &len);
+		if (!compatible)
+			continue;
+
+		name = strchr(compatible, ',');
+		if (!name)
+			name = compatible;
+		else
+			name++;
+
+		if (!strncmp(name, type, len - (name - compatible)))
+			return np;
+	}
+
+	return NULL;
+}
 #else
 static void of_i2c_register_devices(struct i2c_adapter *adap) { }
+static struct device_node *of_i2c_type_to_node(char *type) { return NULL; }
 #endif /* CONFIG_OF */
 
 /* ACPI support code */
-- 
1.8.3.2

[PATCH 1/3] i2c: Provide 'device type' to 'OF device node' look-up

[Lee Jones]

> We have a problem.  There are lots of I2C device ID tables scattered
> around the kernel which are redundant in all Device Tree and/or ACPI
> only supported device drivers.  After recent discussions it has become
> apparent that the only thing blocking the complete removal of these
> tables is the continued support of 'register an I2C device via sysfs'
> functionality.  As the sysfs method doesn't know anything about Device
> Tree or ACPI, we can not pass any nodes in.  This patch searches all
> known Device Tree nodes and attempts to acquire a match from the
> device name provided via sysfs.  It can not fail, but if found assigns
> the matching of_node to i2c_board_info prior to registering.
> 
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---
>  drivers/i2c/i2c-core.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)

[...]

> +static struct device_node *of_i2c_type_to_node(char *type)
> +{
> +	struct device_node *np;
> +	const char *compatible, *name;
> +	int len;
> +
> +	if (!type)
> +		return NULL;
> +
> +	for_each_of_allnodes(np) {
> +		compatible = of_get_property(np, "compatible", &len);
> +		if (!compatible)
> +			continue;
> +
> +		name = strchr(compatible, ',');
> +		if (!name)
> +			name = compatible;
> +		else
> +			name++;
> +
> +		if (!strncmp(name, type, len - (name - compatible)))
> +			return np;
> +	}
> +
> +	return NULL;
> +}

Ah, this _might_ not work if there are more than one devices of the
same type.  I guess I need to check the 'reg' property too.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

[PATCH 1/3] i2c: Provide 'device type' to 'OF device node' look-up

[Grant Likely]

On Mon,  2 Jun 2014 14:41:01 +0100, Lee Jones <lee.jones@linaro.org> wrote:
> We have a problem.  There are lots of I2C device ID tables scattered
> around the kernel which are redundant in all Device Tree and/or ACPI
> only supported device drivers.  After recent discussions it has become
> apparent that the only thing blocking the complete removal of these
> tables is the continued support of 'register an I2C device via sysfs'
> functionality.  As the sysfs method doesn't know anything about Device
> Tree or ACPI, we can not pass any nodes in.  This patch searches all
> known Device Tree nodes and attempts to acquire a match from the
> device name provided via sysfs.  It can not fail, but if found assigns
> the matching of_node to i2c_board_info prior to registering.

Ummm... blech!  :-)

It shouldn't actually be necessary to have a node when instantiating an
i2c_device... in fact, there /shouldn't/ be a node if the device is
getting instantiated by had via sysfs. If there was a node, then I would
expect a device to have been created at the same time.

I think panto's overlays solve the problem where a node actually is
required to instantiate the device by actually adding a node and letting
the i2c subsystem create the associated device automatically.

g.

> 
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---
>  drivers/i2c/i2c-core.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 7c7f4b8..2e47641 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -64,6 +64,7 @@ static DEFINE_IDR(i2c_adapter_idr);
>  
>  static struct device_type i2c_client_type;
>  static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
> +static struct device_node *of_i2c_type_to_node(char *type);
>  
>  static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
>  
> @@ -863,6 +864,8 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
>  		return -EINVAL;
>  	}
>  
> +	info.of_node = of_i2c_type_to_node(info.type);
> +
>  	client = i2c_new_device(adap, &info);
>  	if (!client)
>  		return -EINVAL;
> @@ -1088,8 +1091,36 @@ struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
>  	return i2c_verify_adapter(dev);
>  }
>  EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
> +
> +static struct device_node *of_i2c_type_to_node(char *type)
> +{
> +	struct device_node *np;
> +	const char *compatible, *name;
> +	int len;
> +
> +	if (!type)
> +		return NULL;
> +
> +	for_each_of_allnodes(np) {
> +		compatible = of_get_property(np, "compatible", &len);
> +		if (!compatible)
> +			continue;
> +
> +		name = strchr(compatible, ',');
> +		if (!name)
> +			name = compatible;
> +		else
> +			name++;
> +
> +		if (!strncmp(name, type, len - (name - compatible)))
> +			return np;
> +	}
> +
> +	return NULL;
> +}
>  #else
>  static void of_i2c_register_devices(struct i2c_adapter *adap) { }
> +static struct device_node *of_i2c_type_to_node(char *type) { return NULL; }
>  #endif /* CONFIG_OF */
>  
>  /* ACPI support code */
> -- 
> 1.8.3.2
> 

[PATCH 1/3] i2c: Provide 'device type' to 'OF device node' look-up

[Lee Jones]

> > We have a problem.  There are lots of I2C device ID tables scattered
> > around the kernel which are redundant in all Device Tree and/or ACPI
> > only supported device drivers.  After recent discussions it has become
> > apparent that the only thing blocking the complete removal of these
> > tables is the continued support of 'register an I2C device via sysfs'
> > functionality.  As the sysfs method doesn't know anything about Device
> > Tree or ACPI, we can not pass any nodes in.  This patch searches all
> > known Device Tree nodes and attempts to acquire a match from the
> > device name provided via sysfs.  It can not fail, but if found assigns
> > the matching of_node to i2c_board_info prior to registering.
> 
> Ummm... blech!  :-)
> 
> It shouldn't actually be necessary to have a node when instantiating an
> i2c_device... in fact, there /shouldn't/ be a node if the device is
> getting instantiated by had via sysfs. If there was a node, then I would
> expect a device to have been created at the same time.

You're right.  I realised that about 10 mins after I sent the patch!

> I think panto's overlays solve the problem where a node actually is
> required to instantiate the device by actually adding a node and letting
> the i2c subsystem create the associated device automatically.

This looks like it's exactly what I need.  Pulling the code now.

> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > ---
> >  drivers/i2c/i2c-core.c | 31 +++++++++++++++++++++++++++++++
> >  1 file changed, 31 insertions(+)
> > 
> > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> > index 7c7f4b8..2e47641 100644
> > --- a/drivers/i2c/i2c-core.c
> > +++ b/drivers/i2c/i2c-core.c
> > @@ -64,6 +64,7 @@ static DEFINE_IDR(i2c_adapter_idr);
> >  
> >  static struct device_type i2c_client_type;
> >  static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
> > +static struct device_node *of_i2c_type_to_node(char *type);
> >  
> >  static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
> >  
> > @@ -863,6 +864,8 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
> >  		return -EINVAL;
> >  	}
> >  
> > +	info.of_node = of_i2c_type_to_node(info.type);
> > +
> >  	client = i2c_new_device(adap, &info);
> >  	if (!client)
> >  		return -EINVAL;
> > @@ -1088,8 +1091,36 @@ struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
> >  	return i2c_verify_adapter(dev);
> >  }
> >  EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
> > +
> > +static struct device_node *of_i2c_type_to_node(char *type)
> > +{
> > +	struct device_node *np;
> > +	const char *compatible, *name;
> > +	int len;
> > +
> > +	if (!type)
> > +		return NULL;
> > +
> > +	for_each_of_allnodes(np) {
> > +		compatible = of_get_property(np, "compatible", &len);
> > +		if (!compatible)
> > +			continue;
> > +
> > +		name = strchr(compatible, ',');
> > +		if (!name)
> > +			name = compatible;
> > +		else
> > +			name++;
> > +
> > +		if (!strncmp(name, type, len - (name - compatible)))
> > +			return np;
> > +	}
> > +
> > +	return NULL;
> > +}
> >  #else
> >  static void of_i2c_register_devices(struct i2c_adapter *adap) { }
> > +static struct device_node *of_i2c_type_to_node(char *type) { return NULL; }
> >  #endif /* CONFIG_OF */
> >  
> >  /* ACPI support code */
> 

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

[PATCH 2/3] i2c: Add pointer dereference protection to i2c_match_id()

[Lee Jones]

Here we're providing dereference protection for i2c_match_id(), which
saves us having to do it each time it's called.  We're also stripping
out the (now) needless check in i2c_device_match().  This patch paves
the way for other, similar code trimming.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/i2c/i2c-core.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 2e47641..d0c7180 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -83,6 +83,9 @@ void i2c_transfer_trace_unreg(void)
 static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
 						const struct i2c_client *client)
 {
+	if (!id)
+		return NULL;
+
 	while (id->name[0]) {
 		if (strcmp(client->name, id->name) == 0)
 			return id;
@@ -108,9 +111,10 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
 		return 1;
 
 	driver = to_i2c_driver(drv);
-	/* match on an id table if there is one */
-	if (driver->id_table)
-		return i2c_match_id(driver->id_table, client) != NULL;
+
+	/* Finally an I2C match */
+	if (i2c_match_id(driver->id_table, client))
+		return 1;
 
 	return 0;
 }
-- 
1.8.3.2

[PATCH 2/3] i2c: Add pointer dereference protection to i2c_match_id()

[Grant Likely]

On Mon,  2 Jun 2014 14:41:02 +0100, Lee Jones <lee.jones@linaro.org> wrote:
> Here we're providing dereference protection for i2c_match_id(), which
> saves us having to do it each time it's called.  We're also stripping
> out the (now) needless check in i2c_device_match().  This patch paves
> the way for other, similar code trimming.
> 
> Signed-off-by: Lee Jones <lee.jones@linaro.org>

Seems reasonable.

Acked-by: Grant Likely <grant.likely@linaro.org>

> ---
>  drivers/i2c/i2c-core.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 2e47641..d0c7180 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -83,6 +83,9 @@ void i2c_transfer_trace_unreg(void)
>  static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
>  						const struct i2c_client *client)
>  {
> +	if (!id)
> +		return NULL;
> +
>  	while (id->name[0]) {
>  		if (strcmp(client->name, id->name) == 0)
>  			return id;
> @@ -108,9 +111,10 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
>  		return 1;
>  
>  	driver = to_i2c_driver(drv);
> -	/* match on an id table if there is one */
> -	if (driver->id_table)
> -		return i2c_match_id(driver->id_table, client) != NULL;
> +
> +	/* Finally an I2C match */
> +	if (i2c_match_id(driver->id_table, client))
> +		return 1;
>  
>  	return 0;
>  }
> -- 
> 1.8.3.2
> 

[PATCH 3/3] i2c: Make I2C ID tables non-mandatory for DT'ed and/or ACPI'ed devices

[Lee Jones]

Currently the I2C framework insists on devices supplying an I2C ID
table.  Many of the devices which do so unnecessarily adding quite a
few wasted lines to kernel code.  This patch allows drivers a means
to 'not' supply the aforementioned table and match on either DT
and/or ACPI match tables instead.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/i2c/i2c-core.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index d0c7180..811b78f 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -271,7 +271,18 @@ static int i2c_device_probe(struct device *dev)
 		return 0;
 
 	driver = to_i2c_driver(dev->driver);
-	if (!driver->probe || !driver->id_table)
+	if (!driver->probe)
+		return -EINVAL;
+
+	/*
+	 * An I2C ID table is not madatory, if and only if, a suitable Device
+	 * Tree and/or ACPI match table entry is supplied for the probing
+	 * device.
+	 *
+	 * TODO: Provide 'device type' to 'ACPI node' call and match here.
+	 */
+	if (!driver->id_table &&
+	    !of_match_device(dev->driver->of_match_table, dev))
 		return -ENODEV;
 
 	if (!device_can_wakeup(&client->dev))
-- 
1.8.3.2

[PATCH 3/3] i2c: Make I2C ID tables non-mandatory for DT'ed and/or ACPI'ed devices

[One Thousand Gnomes]

On Mon,  2 Jun 2014 14:41:03 +0100
Lee Jones <lee.jones@linaro.org> wrote:

> Currently the I2C framework insists on devices supplying an I2C ID
> table.  Many of the devices which do so unnecessarily adding quite a
> few wasted lines to kernel code.  This patch allows drivers a means
> to 'not' supply the aforementioned table and match on either DT
> and/or ACPI match tables instead.
> 
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---
>  drivers/i2c/i2c-core.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index d0c7180..811b78f 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -271,7 +271,18 @@ static int i2c_device_probe(struct device *dev)
>  		return 0;
>  
>  	driver = to_i2c_driver(dev->driver);
> -	if (!driver->probe || !driver->id_table)
> +	if (!driver->probe)
> +		return -EINVAL;
> +
> +	/*
> +	 * An I2C ID table is not madatory, if and only if, a suitable Device

typo "madatory"..

> +	 * Tree and/or ACPI match table entry is supplied for the probing
> +	 * device.
> +	 *
> +	 * TODO: Provide 'device type' to 'ACPI node' call and match here.
> +	 */
> +	if (!driver->id_table &&
> +	    !of_match_device(dev->driver->of_match_table, dev))
>  		return -ENODEV;
>  

Looks sensible to me other than that.

>  	if (!device_can_wakeup(&client->dev))

[PATCH 3/3] i2c: Make I2C ID tables non-mandatory for DT'ed and/or ACPI'ed devices

[Lee Jones]

On Mon, 02 Jun 2014, One Thousand Gnomes wrote:

> On Mon,  2 Jun 2014 14:41:03 +0100
> Lee Jones <lee.jones@linaro.org> wrote:
> 
> > Currently the I2C framework insists on devices supplying an I2C ID
> > table.  Many of the devices which do so unnecessarily adding quite a
> > few wasted lines to kernel code.  This patch allows drivers a means
> > to 'not' supply the aforementioned table and match on either DT
> > and/or ACPI match tables instead.
> > 
> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > ---
> >  drivers/i2c/i2c-core.c | 13 ++++++++++++-
> >  1 file changed, 12 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> > index d0c7180..811b78f 100644
> > --- a/drivers/i2c/i2c-core.c
> > +++ b/drivers/i2c/i2c-core.c
> > @@ -271,7 +271,18 @@ static int i2c_device_probe(struct device *dev)
> >  		return 0;
> >  
> >  	driver = to_i2c_driver(dev->driver);
> > -	if (!driver->probe || !driver->id_table)
> > +	if (!driver->probe)
> > +		return -EINVAL;
> > +
> > +	/*
> > +	 * An I2C ID table is not madatory, if and only if, a suitable Device
> 
> typo "madatory"..
> 
> > +	 * Tree and/or ACPI match table entry is supplied for the probing
> > +	 * device.
> > +	 *
> > +	 * TODO: Provide 'device type' to 'ACPI node' call and match here.
> > +	 */
> > +	if (!driver->id_table &&
> > +	    !of_match_device(dev->driver->of_match_table, dev))
> >  		return -ENODEV;
> >  
> 
> Looks sensible to me other than that.

Can I add your Ack once the typo is fixed?

> >  	if (!device_can_wakeup(&client->dev))

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

[PATCH 3/3] i2c: Make I2C ID tables non-mandatory for DT'ed and/or ACPI'ed devices

[Grant Likely]

On Mon,  2 Jun 2014 14:41:03 +0100, Lee Jones <lee.jones@linaro.org> wrote:
> Currently the I2C framework insists on devices supplying an I2C ID
> table.  Many of the devices which do so unnecessarily adding quite a
> few wasted lines to kernel code.  This patch allows drivers a means
> to 'not' supply the aforementioned table and match on either DT
> and/or ACPI match tables instead.
> 
> Signed-off-by: Lee Jones <lee.jones@linaro.org>

Looks reasonable.

g.

> ---
>  drivers/i2c/i2c-core.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index d0c7180..811b78f 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -271,7 +271,18 @@ static int i2c_device_probe(struct device *dev)
>  		return 0;
>  
>  	driver = to_i2c_driver(dev->driver);
> -	if (!driver->probe || !driver->id_table)
> +	if (!driver->probe)
> +		return -EINVAL;
> +
> +	/*
> +	 * An I2C ID table is not madatory, if and only if, a suitable Device
> +	 * Tree and/or ACPI match table entry is supplied for the probing
> +	 * device.
> +	 *
> +	 * TODO: Provide 'device type' to 'ACPI node' call and match here.
> +	 */
> +	if (!driver->id_table &&
> +	    !of_match_device(dev->driver->of_match_table, dev))
>  		return -ENODEV;
>  
>  	if (!device_can_wakeup(&client->dev))
> -- 
> 1.8.3.2
> 

[PATCH 3/3] i2c: Make I2C ID tables non-mandatory for DT'ed and/or ACPI'ed devices

[Lee Jones]

On Mon, 02 Jun 2014, Grant Likely wrote:
> On Mon,  2 Jun 2014 14:41:03 +0100, Lee Jones <lee.jones@linaro.org> wrote:
> > Currently the I2C framework insists on devices supplying an I2C ID
> > table.  Many of the devices which do so unnecessarily adding quite a
> > few wasted lines to kernel code.  This patch allows drivers a means
> > to 'not' supply the aforementioned table and match on either DT
> > and/or ACPI match tables instead.
> > 
> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> 
> Looks reasonable.

Can I add your Ack?

> g.
> 
> > ---
> >  drivers/i2c/i2c-core.c | 13 ++++++++++++-
> >  1 file changed, 12 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> > index d0c7180..811b78f 100644
> > --- a/drivers/i2c/i2c-core.c
> > +++ b/drivers/i2c/i2c-core.c
> > @@ -271,7 +271,18 @@ static int i2c_device_probe(struct device *dev)
> >  		return 0;
> >  
> >  	driver = to_i2c_driver(dev->driver);
> > -	if (!driver->probe || !driver->id_table)
> > +	if (!driver->probe)
> > +		return -EINVAL;
> > +
> > +	/*
> > +	 * An I2C ID table is not madatory, if and only if, a suitable Device
> > +	 * Tree and/or ACPI match table entry is supplied for the probing
> > +	 * device.
> > +	 *
> > +	 * TODO: Provide 'device type' to 'ACPI node' call and match here.
> > +	 */
> > +	if (!driver->id_table &&
> > +	    !of_match_device(dev->driver->of_match_table, dev))
> >  		return -ENODEV;
> >  
> >  	if (!device_can_wakeup(&client->dev))
> 

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

[PATCH 3/3] i2c: Make I2C ID tables non-mandatory for DT'ed and/or ACPI'ed devices

[Grant Likely]

On Tue, 3 Jun 2014 09:11:09 +0100, Lee Jones <lee.jones@linaro.org> wrote:
> On Mon, 02 Jun 2014, Grant Likely wrote:
> > On Mon,  2 Jun 2014 14:41:03 +0100, Lee Jones <lee.jones@linaro.org> wrote:
> > > Currently the I2C framework insists on devices supplying an I2C ID
> > > table.  Many of the devices which do so unnecessarily adding quite a
> > > few wasted lines to kernel code.  This patch allows drivers a means
> > > to 'not' supply the aforementioned table and match on either DT
> > > and/or ACPI match tables instead.
> > > 
> > > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > 
> > Looks reasonable.
> 
> Can I add your Ack?

Acked-by: Grant Likely <grant.likely@linaro.org>

> 
> > g.
> > 
> > > ---
> > >  drivers/i2c/i2c-core.c | 13 ++++++++++++-
> > >  1 file changed, 12 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> > > index d0c7180..811b78f 100644
> > > --- a/drivers/i2c/i2c-core.c
> > > +++ b/drivers/i2c/i2c-core.c
> > > @@ -271,7 +271,18 @@ static int i2c_device_probe(struct device *dev)
> > >  		return 0;
> > >  
> > >  	driver = to_i2c_driver(dev->driver);
> > > -	if (!driver->probe || !driver->id_table)
> > > +	if (!driver->probe)
> > > +		return -EINVAL;
> > > +
> > > +	/*
> > > +	 * An I2C ID table is not madatory, if and only if, a suitable Device
> > > +	 * Tree and/or ACPI match table entry is supplied for the probing
> > > +	 * device.
> > > +	 *
> > > +	 * TODO: Provide 'device type' to 'ACPI node' call and match here.
> > > +	 */
> > > +	if (!driver->id_table &&
> > > +	    !of_match_device(dev->driver->of_match_table, dev))
> > >  		return -ENODEV;
> > >  
> > >  	if (!device_can_wakeup(&client->dev))
> > 
> 
> -- 
> Lee Jones
> Linaro STMicroelectronics Landing Team Lead
> Linaro.org ??? Open source software for ARM SoCs
> Follow Linaro: Facebook | Twitter | Blog