i2c: move of helpers into the core

[Added Jerry as he found out a problem when acpi_i2c is being build as a
module, this should solve it as well.]

On Tue, Aug 20, 2013 at 01:25:27AM +0200, Rafael J. Wysocki wrote:
> On Monday, August 19, 2013 04:56:19 PM Stephen Warren wrote:
> > On 08/19/2013 05:04 PM, Rafael J. Wysocki wrote:
> > > On Monday, August 19, 2013 03:19:18 PM Wolfram Sang wrote:
> > >> I2C of helpers used to live in of_i2c.c but experience (from SPI) shows
> > >> that it is much cleaner to have this in the core. This also removes a
> > >> circular dependency between the helpers and the core, and so we can
> > >> finally register child nodes in the core instead of doing this manually
> > >> in each driver. So, fix the drivers and documentation, too.
> > > 
> > > Perhaps we should do the analogous for ACPI then?

Here is the ACPI version based on the current patch from Wolfram (there is
a compile error because of missing dummy implementation of
of_i2c_register_devices())

From: Mika Westerberg <mika.westerberg@linux.intel.com>
Subject: [PATCH] i2c: move ACPI helpers into the core

This follows what has already been done for the DeviceTree helpers. Move
the ACPI helpers from drivers/acpi/acpi_i2c.c to the I2C core and update
documentation accordingly.

This also solves a problem reported by Jerry Snitselaar that we can't build
the ACPI I2C helpers as a module.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 Documentation/acpi/enumeration.txt          |  15 +---
 drivers/acpi/Kconfig                        |   6 --
 drivers/acpi/Makefile                       |   1 -
 drivers/acpi/acpi_i2c.c                     | 103 ----------------------------
 drivers/i2c/busses/i2c-designware-platdrv.c |   1 -
 drivers/i2c/i2c-core.c                      |  91 ++++++++++++++++++++++++
 include/linux/i2c.h                         |   6 --
 7 files changed, 94 insertions(+), 129 deletions(-)
 delete mode 100644 drivers/acpi/acpi_i2c.c

On Tuesday, August 20, 2013 12:28:13 PM Mika Westerberg wrote:
> [Added Jerry as he found out a problem when acpi_i2c is being build as a
> module, this should solve it as well.]
> 
> On Tue, Aug 20, 2013 at 01:25:27AM +0200, Rafael J. Wysocki wrote:
> > On Monday, August 19, 2013 04:56:19 PM Stephen Warren wrote:
> > > On 08/19/2013 05:04 PM, Rafael J. Wysocki wrote:
> > > > On Monday, August 19, 2013 03:19:18 PM Wolfram Sang wrote:
> > > >> I2C of helpers used to live in of_i2c.c but experience (from SPI) shows
> > > >> that it is much cleaner to have this in the core. This also removes a
> > > >> circular dependency between the helpers and the core, and so we can
> > > >> finally register child nodes in the core instead of doing this manually
> > > >> in each driver. So, fix the drivers and documentation, too.
> > > > 
> > > > Perhaps we should do the analogous for ACPI then?
> 
> Here is the ACPI version based on the current patch from Wolfram (there is
> a compile error because of missing dummy implementation of
> of_i2c_register_devices())
> 
> From: Mika Westerberg <mika.westerberg@linux.intel.com>
> Subject: [PATCH] i2c: move ACPI helpers into the core
> 
> This follows what has already been done for the DeviceTree helpers. Move
> the ACPI helpers from drivers/acpi/acpi_i2c.c to the I2C core and update
> documentation accordingly.
> 
> This also solves a problem reported by Jerry Snitselaar that we can't build
> the ACPI I2C helpers as a module.
> 
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

> ---
>  Documentation/acpi/enumeration.txt          |  15 +---
>  drivers/acpi/Kconfig                        |   6 --
>  drivers/acpi/Makefile                       |   1 -
>  drivers/acpi/acpi_i2c.c                     | 103 ----------------------------
>  drivers/i2c/busses/i2c-designware-platdrv.c |   1 -
>  drivers/i2c/i2c-core.c                      |  91 ++++++++++++++++++++++++
>  include/linux/i2c.h                         |   6 --
>  7 files changed, 94 insertions(+), 129 deletions(-)
>  delete mode 100644 drivers/acpi/acpi_i2c.c
> 
> diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt
> index 958266e..d977778 100644
> --- a/Documentation/acpi/enumeration.txt
> +++ b/Documentation/acpi/enumeration.txt
> @@ -228,18 +228,9 @@ ACPI handle like:
>  I2C serial bus support
>  ~~~~~~~~~~~~~~~~~~~~~~
>  The slaves behind I2C bus controller only need to add the ACPI IDs like
> -with the platform and SPI drivers. However the I2C bus controller driver
> -needs to call acpi_i2c_register_devices() after it has added the adapter.
> -
> -An I2C bus (controller) driver does:
> -
> -	...
> -	ret = i2c_add_numbered_adapter(adapter);
> -	if (ret)
> -		/* handle error */
> -
> -	/* Enumerate the slave devices behind this bus via ACPI */
> -	acpi_i2c_register_devices(adapter);
> +with the platform and SPI drivers. The I2C core automatically enumerates
> +any slave devices behind the controller device once the adapter is
> +registered.
>  
>  Below is an example of how to add ACPI support to the existing mpu3050
>  input driver:
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 100bd72..4e0162f 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -180,12 +180,6 @@ config ACPI_DOCK
>  	  This driver supports ACPI-controlled docking stations and removable
>  	  drive bays such as the IBM Ultrabay and the Dell Module Bay.
>  
> -config ACPI_I2C
> -	def_tristate I2C
> -	depends on I2C
> -	help
> -	  ACPI I2C enumeration support.
> -
>  config ACPI_PROCESSOR
>  	tristate "Processor"
>  	select THERMAL
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 81dbeb8..cdaf68b 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -73,7 +73,6 @@ obj-$(CONFIG_ACPI_HED)		+= hed.o
>  obj-$(CONFIG_ACPI_EC_DEBUGFS)	+= ec_sys.o
>  obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
>  obj-$(CONFIG_ACPI_BGRT)		+= bgrt.o
> -obj-$(CONFIG_ACPI_I2C)		+= acpi_i2c.o
>  
>  # processor has its own "processor." module_param namespace
>  processor-y			:= processor_driver.o processor_throttling.o
> diff --git a/drivers/acpi/acpi_i2c.c b/drivers/acpi/acpi_i2c.c
> deleted file mode 100644
> index a82c762..0000000
> --- a/drivers/acpi/acpi_i2c.c
> +++ /dev/null
> @@ -1,103 +0,0 @@
> -/*
> - * ACPI I2C enumeration support
> - *
> - * Copyright (C) 2012, Intel Corporation
> - * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
> - *
> - * This program is free software; you can redistribute it and/or modify
> - * it under the terms of the GNU General Public License version 2 as
> - * published by the Free Software Foundation.
> - */
> -
> -#include <linux/acpi.h>
> -#include <linux/device.h>
> -#include <linux/export.h>
> -#include <linux/i2c.h>
> -#include <linux/ioport.h>
> -
> -ACPI_MODULE_NAME("i2c");
> -
> -static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
> -{
> -	struct i2c_board_info *info = data;
> -
> -	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
> -		struct acpi_resource_i2c_serialbus *sb;
> -
> -		sb = &ares->data.i2c_serial_bus;
> -		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
> -			info->addr = sb->slave_address;
> -			if (sb->access_mode == ACPI_I2C_10BIT_MODE)
> -				info->flags |= I2C_CLIENT_TEN;
> -		}
> -	} else if (info->irq < 0) {
> -		struct resource r;
> -
> -		if (acpi_dev_resource_interrupt(ares, 0, &r))
> -			info->irq = r.start;
> -	}
> -
> -	/* Tell the ACPI core to skip this resource */
> -	return 1;
> -}
> -
> -static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
> -				       void *data, void **return_value)
> -{
> -	struct i2c_adapter *adapter = data;
> -	struct list_head resource_list;
> -	struct i2c_board_info info;
> -	struct acpi_device *adev;
> -	int ret;
> -
> -	if (acpi_bus_get_device(handle, &adev))
> -		return AE_OK;
> -	if (acpi_bus_get_status(adev) || !adev->status.present)
> -		return AE_OK;
> -
> -	memset(&info, 0, sizeof(info));
> -	info.acpi_node.handle = handle;
> -	info.irq = -1;
> -
> -	INIT_LIST_HEAD(&resource_list);
> -	ret = acpi_dev_get_resources(adev, &resource_list,
> -				     acpi_i2c_add_resource, &info);
> -	acpi_dev_free_resource_list(&resource_list);
> -
> -	if (ret < 0 || !info.addr)
> -		return AE_OK;
> -
> -	strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
> -	if (!i2c_new_device(adapter, &info)) {
> -		dev_err(&adapter->dev,
> -			"failed to add I2C device %s from ACPI\n",
> -			dev_name(&adev->dev));
> -	}
> -
> -	return AE_OK;
> -}
> -
> -/**
> - * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
> - * @adapter: pointer to adapter
> - *
> - * Enumerate all I2C slave devices behind this adapter by walking the ACPI
> - * namespace. When a device is found it will be added to the Linux device
> - * model and bound to the corresponding ACPI handle.
> - */
> -void acpi_i2c_register_devices(struct i2c_adapter *adapter)
> -{
> -	acpi_handle handle;
> -	acpi_status status;
> -
> -	handle = ACPI_HANDLE(adapter->dev.parent);
> -	if (!handle)
> -		return;
> -
> -	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
> -				     acpi_i2c_add_device, NULL,
> -				     adapter, NULL);
> -	if (ACPI_FAILURE(status))
> -		dev_warn(&adapter->dev, "failed to enumerate I2C slaves\n");
> -}
> -EXPORT_SYMBOL_GPL(acpi_i2c_register_devices);
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> index 27ea436..1240fd6 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -171,7 +171,6 @@ static int dw_i2c_probe(struct platform_device *pdev)
>  		dev_err(&pdev->dev, "failure adding adapter\n");
>  		return r;
>  	}
> -	acpi_i2c_register_devices(adap);
>  
>  	pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
>  	pm_runtime_use_autosuspend(&pdev->dev);
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 321b7ca..cc80432 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -1056,6 +1056,96 @@ struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
>  EXPORT_SYMBOL(of_find_i2c_device_by_node);
>  #endif /* CONFIG_OF */
>  
> +/* ACPI support code */
> +
> +#ifdef CONFIG_ACPI
> +static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
> +{
> +	struct i2c_board_info *info = data;
> +
> +	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
> +		struct acpi_resource_i2c_serialbus *sb;
> +
> +		sb = &ares->data.i2c_serial_bus;
> +		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
> +			info->addr = sb->slave_address;
> +			if (sb->access_mode == ACPI_I2C_10BIT_MODE)
> +				info->flags |= I2C_CLIENT_TEN;
> +		}
> +	} else if (info->irq < 0) {
> +		struct resource r;
> +
> +		if (acpi_dev_resource_interrupt(ares, 0, &r))
> +			info->irq = r.start;
> +	}
> +
> +	/* Tell the ACPI core to skip this resource */
> +	return 1;
> +}
> +
> +static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
> +				       void *data, void **return_value)
> +{
> +	struct i2c_adapter *adapter = data;
> +	struct list_head resource_list;
> +	struct i2c_board_info info;
> +	struct acpi_device *adev;
> +	int ret;
> +
> +	if (acpi_bus_get_device(handle, &adev))
> +		return AE_OK;
> +	if (acpi_bus_get_status(adev) || !adev->status.present)
> +		return AE_OK;
> +
> +	memset(&info, 0, sizeof(info));
> +	info.acpi_node.handle = handle;
> +	info.irq = -1;
> +
> +	INIT_LIST_HEAD(&resource_list);
> +	ret = acpi_dev_get_resources(adev, &resource_list,
> +				     acpi_i2c_add_resource, &info);
> +	acpi_dev_free_resource_list(&resource_list);
> +
> +	if (ret < 0 || !info.addr)
> +		return AE_OK;
> +
> +	strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
> +	if (!i2c_new_device(adapter, &info)) {
> +		dev_err(&adapter->dev,
> +			"failed to add I2C device %s from ACPI\n",
> +			dev_name(&adev->dev));
> +	}
> +
> +	return AE_OK;
> +}
> +
> +/**
> + * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
> + * @adapter: pointer to adapter
> + *
> + * Enumerate all I2C slave devices behind this adapter by walking the ACPI
> + * namespace. When a device is found it will be added to the Linux device
> + * model and bound to the corresponding ACPI handle.
> + */
> +static void acpi_i2c_register_devices(struct i2c_adapter *adapter)
> +{
> +	acpi_handle handle;
> +	acpi_status status;
> +
> +	handle = ACPI_HANDLE(adapter->dev.parent);
> +	if (!handle)
> +		return;
> +
> +	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
> +				     acpi_i2c_add_device, NULL,
> +				     adapter, NULL);
> +	if (ACPI_FAILURE(status))
> +		dev_warn(&adapter->dev, "failed to enumerate I2C slaves\n");
> +}
> +#else
> +static inline void acpi_i2c_register_devices(struct i2c_adapter *adapter) {}
> +#endif /* CONFIG_ACPI */
> +
>  static int i2c_do_add_adapter(struct i2c_driver *driver,
>  			      struct i2c_adapter *adap)
>  {
> @@ -1161,6 +1251,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
>  exit_recovery:
>  	/* create pre-declared device nodes */
>  	of_i2c_register_devices(adap);
> +	acpi_i2c_register_devices(adap);
>  
>  	if (adap->nr < __i2c_first_dynamic_bus_num)
>  		i2c_scan_static_board_info(adap);
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index 2189189..7670d99 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -562,10 +562,4 @@ static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node
>  }
>  #endif /* CONFIG_OF */
>  
> -#if IS_ENABLED(CONFIG_ACPI_I2C)
> -extern void acpi_i2c_register_devices(struct i2c_adapter *adap);
> -#else
> -static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) {}
> -#endif
> -
>  #endif /* _LINUX_I2C_H */
>

On Tue, Aug 20, 2013 at 12:28:13PM +0300, Mika Westerberg wrote:
> [Added Jerry as he found out a problem when acpi_i2c is being build as a
> module, this should solve it as well.]
> 
> On Tue, Aug 20, 2013 at 01:25:27AM +0200, Rafael J. Wysocki wrote:
> > On Monday, August 19, 2013 04:56:19 PM Stephen Warren wrote:
> > > On 08/19/2013 05:04 PM, Rafael J. Wysocki wrote:
> > > > On Monday, August 19, 2013 03:19:18 PM Wolfram Sang wrote:
> > > >> I2C of helpers used to live in of_i2c.c but experience (from SPI) shows
> > > >> that it is much cleaner to have this in the core. This also removes a
> > > >> circular dependency between the helpers and the core, and so we can
> > > >> finally register child nodes in the core instead of doing this manually
> > > >> in each driver. So, fix the drivers and documentation, too.
> > > > 
> > > > Perhaps we should do the analogous for ACPI then?
> 
> Here is the ACPI version based on the current patch from Wolfram (there is
> a compile error because of missing dummy implementation of
> of_i2c_register_devices())
> 
> From: Mika Westerberg <mika.westerberg@linux.intel.com>
> Subject: [PATCH] i2c: move ACPI helpers into the core
> 
> This follows what has already been done for the DeviceTree helpers. Move
> the ACPI helpers from drivers/acpi/acpi_i2c.c to the I2C core and update
> documentation accordingly.
> 
> This also solves a problem reported by Jerry Snitselaar that we can't build
> the ACPI I2C helpers as a module.
> 
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Nice, one thing, though:

>  	/* create pre-declared device nodes */
>  	of_i2c_register_devices(adap);
> +	acpi_i2c_register_devices(adap);

I prefer the if (IS_ENABLED()) solution and will use this in my V2 as
well.

On Tue, Aug 20, 2013 at 04:30:43PM +0200, Wolfram Sang wrote:
> On Tue, Aug 20, 2013 at 12:28:13PM +0300, Mika Westerberg wrote:
> > [Added Jerry as he found out a problem when acpi_i2c is being build as a
> > module, this should solve it as well.]
> > 
> > On Tue, Aug 20, 2013 at 01:25:27AM +0200, Rafael J. Wysocki wrote:
> > > On Monday, August 19, 2013 04:56:19 PM Stephen Warren wrote:
> > > > On 08/19/2013 05:04 PM, Rafael J. Wysocki wrote:
> > > > > On Monday, August 19, 2013 03:19:18 PM Wolfram Sang wrote:
> > > > >> I2C of helpers used to live in of_i2c.c but experience (from SPI) shows
> > > > >> that it is much cleaner to have this in the core. This also removes a
> > > > >> circular dependency between the helpers and the core, and so we can
> > > > >> finally register child nodes in the core instead of doing this manually
> > > > >> in each driver. So, fix the drivers and documentation, too.
> > > > > 
> > > > > Perhaps we should do the analogous for ACPI then?
> > 
> > Here is the ACPI version based on the current patch from Wolfram (there is
> > a compile error because of missing dummy implementation of
> > of_i2c_register_devices())
> > 
> > From: Mika Westerberg <mika.westerberg@linux.intel.com>
> > Subject: [PATCH] i2c: move ACPI helpers into the core
> > 
> > This follows what has already been done for the DeviceTree helpers. Move
> > the ACPI helpers from drivers/acpi/acpi_i2c.c to the I2C core and update
> > documentation accordingly.
> > 
> > This also solves a problem reported by Jerry Snitselaar that we can't build
> > the ACPI I2C helpers as a module.
> > 
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> 
> Nice, one thing, though:
> 
> >  	/* create pre-declared device nodes */
> >  	of_i2c_register_devices(adap);
> > +	acpi_i2c_register_devices(adap);
> 
> I prefer the if (IS_ENABLED()) solution and will use this in my V2 as
> well.

For the ACPI part we need to have the dummy stub because CONFIG_ACPI is
needed in order to be able to call the ACPI APIs -- there are still
functions that are only available when CONFIG_ACPI is enabled.
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