of: i2c: Export single device registration method

Dynamically inserting i2c client device nodes requires the use
of a single device registration method. Rework and export it.

Don't be put off by the weird patch format, it's a simple move
of the operations applied on each device to a function.

Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>
---
 drivers/i2c/i2c-core.c | 99 +++++++++++++++++++++++++++-----------------------
 include/linux/i2c.h    | 10 +++++
 2 files changed, 64 insertions(+), 45 deletions(-)

Hi!

On 05/11/13 18:57, ext Pantelis Antoniou wrote:
> Dynamically inserting i2c client device nodes requires the use
> of a single device registration method. Rework and export it.
> 
> Don't be put off by the weird patch format, it's a simple move
> of the operations applied on each device to a function.
> 
> Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>

We use the "same" patch since kernel 3.10.0, so:
Acked-by: Alexander Sverdlin <alexander.sverdlin@nsn.com>
Tested-by: Alexander Sverdlin <alexander.sverdlin@nsn.com>

> ---
>  drivers/i2c/i2c-core.c | 99 +++++++++++++++++++++++++++-----------------------
>  include/linux/i2c.h    | 10 +++++
>  2 files changed, 64 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 3be58f8..9be6803 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -49,6 +49,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/acpi.h>
>  #include <asm/uaccess.h>
> +#include <linux/err.h>
>  
>  #include "i2c-core.h"
>  
> @@ -963,63 +964,71 @@ static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
>  /* OF support code */
>  
>  #if IS_ENABLED(CONFIG_OF)
> -static void of_i2c_register_devices(struct i2c_adapter *adap)
> +struct i2c_client *
> +of_i2c_register_device(struct i2c_adapter *adap,
> +		struct device_node *node)
>  {
> -	void *result;
> -	struct device_node *node;
> +	struct i2c_client *result;
> +	struct i2c_board_info info = {};
> +	struct dev_archdata dev_ad = {};
> +	const __be32 *addr;
> +	int len;
>  
> -	/* Only register child devices if the adapter has a node pointer set */
> -	if (!adap->dev.of_node)
> -		return;
> +	dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
>  
> -	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
> +	if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
> +		dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
> +			node->full_name);
> +		return ERR_PTR(-EINVAL);
> +	}
>  
> -	for_each_available_child_of_node(adap->dev.of_node, node) {
> -		struct i2c_board_info info = {};
> -		struct dev_archdata dev_ad = {};
> -		const __be32 *addr;
> -		int len;
> +	addr = of_get_property(node, "reg", &len);
> +	if (!addr || (len < sizeof(int))) {
> +		dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
> +			node->full_name);
> +		return ERR_PTR(-EINVAL);
> +	}
>  
> -		dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
> +	info.addr = be32_to_cpup(addr);
> +	if (info.addr > (1 << 10) - 1) {
> +		dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
> +			info.addr, node->full_name);
> +		return ERR_PTR(-EINVAL);
> +	}
>  
> -		if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
> -			dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
> -				node->full_name);
> -			continue;
> -		}
> +	info.irq = irq_of_parse_and_map(node, 0);
> +	info.of_node = of_node_get(node);
> +	info.archdata = &dev_ad;
>  
> -		addr = of_get_property(node, "reg", &len);
> -		if (!addr || (len < sizeof(int))) {
> -			dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
> -				node->full_name);
> -			continue;
> -		}
> +	if (of_get_property(node, "wakeup-source", NULL))
> +		info.flags |= I2C_CLIENT_WAKE;
>  
> -		info.addr = be32_to_cpup(addr);
> -		if (info.addr > (1 << 10) - 1) {
> -			dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
> -				info.addr, node->full_name);
> -			continue;
> -		}
> +	request_module("%s%s", I2C_MODULE_PREFIX, info.type);
>  
> -		info.irq = irq_of_parse_and_map(node, 0);
> -		info.of_node = of_node_get(node);
> -		info.archdata = &dev_ad;
> +	result = i2c_new_device(adap, &info);
> +	if (result == NULL) {
> +		dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
> +			node->full_name);
> +		of_node_put(node);
> +		irq_dispose_mapping(info.irq);
> +		return ERR_PTR(-EINVAL);
> +	}
> +	return result;
> +}
> +EXPORT_SYMBOL(of_i2c_register_device);
>  
> -		if (of_get_property(node, "wakeup-source", NULL))
> -			info.flags |= I2C_CLIENT_WAKE;
> +static void of_i2c_register_devices(struct i2c_adapter *adap)
> +{
> +	struct device_node *node;
>  
> -		request_module("%s%s", I2C_MODULE_PREFIX, info.type);
> +	/* Only register child devices if the adapter has a node pointer set */
> +	if (!adap->dev.of_node)
> +		return;
>  
> -		result = i2c_new_device(adap, &info);
> -		if (result == NULL) {
> -			dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
> -				node->full_name);
> -			of_node_put(node);
> -			irq_dispose_mapping(info.irq);
> -			continue;
> -		}
> -	}
> +	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
> +
> +	for_each_available_child_of_node(adap->dev.of_node, node)
> +		of_i2c_register_device(adap, node);
>  }
>  
>  static int of_dev_node_match(struct device *dev, void *data)
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index 2ab11dc..10bcf86 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -545,6 +545,9 @@ static inline int i2c_adapter_id(struct i2c_adapter *adap)
>  #endif /* I2C */
>  
>  #if IS_ENABLED(CONFIG_OF)
> +struct i2c_client *
> +of_i2c_register_device(struct i2c_adapter *adap, struct device_node *node);
> +
>  /* must call put_device() when done with returned i2c_client device */
>  extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
>  
> @@ -553,6 +556,13 @@ extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
>  
>  #else
>  
> +static inline struct i2c_client *
> +of_i2c_register_device(struct i2c_adapter *adap,
> +		struct device_node *node)
> +{
> +	return ERR_PTR(-ENODEV);
> +}
> +
>  static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
>  {
>  	return NULL;
>

On Tue, Nov 05, 2013 at 07:57:20PM +0200, Pantelis Antoniou wrote:
> Dynamically inserting i2c client device nodes requires the use
> of a single device registration method. Rework and export it.
> 
> Don't be put off by the weird patch format, it's a simple move
> of the operations applied on each device to a function.
> 
> Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>

Are there public patches somewhere showing the use case of this patch?

Hi Wolfram,

On Jan 13, 2014, at 2:17 PM, Wolfram Sang wrote:

> On Tue, Nov 05, 2013 at 07:57:20PM +0200, Pantelis Antoniou wrote:
>> Dynamically inserting i2c client device nodes requires the use
>> of a single device registration method. Rework and export it.
>> 
>> Don't be put off by the weird patch format, it's a simple move
>> of the operations applied on each device to a function.
>> 
>> Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>
> 
> Are there public patches somewhere showing the use case of this patch?
> 

Of course.

> https://github.com/pantoniou/linux-beagle-track-mainline/blob/merge-min-20131105/drivers/of/overlay.c#L454

This is the how i2c DT overlays work, and is the method that the beaglebone releases work with i2c devices.

I am in the process of updating the patchset, but this part of the patch is unaffected.

Regards

-- Pantelis

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