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Date: Tue, 20 Aug 2013 14:31:15 +0200
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc: Wolfram Sang <wsa@...-dreams.de>,
Stephen Warren <swarren@...dotorg.org>,
linux-i2c@...r.kernel.org, linux-acpi@...r.kernel.org,
linux-kernel@...r.kernel.org,
Jerry Snitselaar <jerry.snitselaar@...cle.com>
Subject: Re: [PATCH] i2c: move of helpers into the core
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@...ux.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@...ux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.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@...ux.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 */
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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