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Date: Fri, 16 Nov 2012 11:09:03 +0100
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Mika Westerberg <mika.westerberg@...ux.intel.com>,
khali@...ux-fr.org, ben-linux@...ff.org, w.sang@...gutronix.de
Cc: linux-kernel@...r.kernel.org, lenb@...nel.org,
rafael.j.wysocki@...el.com, broonie@...nsource.wolfsonmicro.com,
grant.likely@...retlab.ca, linus.walleij@...aro.org,
bhelgaas@...gle.com, mathias.nyman@...ux.intel.com,
linux-acpi@...r.kernel.org
Subject: Re: [PATCH v2 3/3] i2c / ACPI: add ACPI enumeration support
On Thursday, November 15, 2012 01:03:17 PM Mika Westerberg wrote:
> ACPI 5 introduced I2cSerialBus resource that makes it possible to enumerate
> and configure the I2C slave devices behind the I2C controller. This patch
> adds helper functions to support I2C slave enumeration.
>
> An ACPI enabled I2C controller driver only needs to call acpi_i2c_register_devices()
> in order to get its slave devices enumerated, created and bound to the
> corresponding ACPI handle.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Are there any objections against this patch or comments?
Worfram? Jean? Ben?
Rafael
> ---
> drivers/acpi/Kconfig | 6 ++
> drivers/acpi/Makefile | 1 +
> drivers/acpi/acpi_i2c.c | 212 ++++++++++++++++++++++++++++++++++++++++++++++
> drivers/i2c/i2c-core.c | 10 +++
> include/linux/acpi_i2c.h | 27 ++++++
> 5 files changed, 256 insertions(+)
> create mode 100644 drivers/acpi/acpi_i2c.c
> create mode 100644 include/linux/acpi_i2c.h
>
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 119d58d..0300bf6 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -181,6 +181,12 @@ 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 7289828..2a4502b 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -70,6 +70,7 @@ 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
> new file mode 100644
> index 0000000..5bf2dad
> --- /dev/null
> +++ b/drivers/acpi/acpi_i2c.c
> @@ -0,0 +1,212 @@
> +/*
> + * 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/err.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 acpi_resource_i2c_serialbus *sb;
> + struct i2c_board_info *info = data;
> +
> + if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
> + return 0;
> +
> + sb = &ares->data.i2c_serial_bus;
> + if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
> + return 0;
> +
> + info->addr = sb->slave_address;
> + if (sb->access_mode == ACPI_I2C_10BIT_MODE)
> + info->flags |= I2C_CLIENT_TEN;
> +
> + 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 resource_list_entry *rentry;
> + 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));
> +
> + INIT_LIST_HEAD(&resource_list);
> + ret = acpi_dev_get_resources(adev, &resource_list,
> + acpi_i2c_add_resource, &info);
> + if (ret < 0)
> + return AE_OK;
> +
> + list_for_each_entry(rentry, &resource_list, node) {
> + struct resource *r = &rentry->res;
> +
> + if (resource_type(r) == IORESOURCE_IRQ) {
> + info.irq = r->start;
> + break;
> + }
> + }
> +
> + acpi_dev_free_resource_list(&resource_list);
> +
> + if (!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 = adapter->dev.acpi_handle;
> + 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);
> +
> +struct acpi_i2c_find {
> + acpi_handle handle;
> + u16 addr;
> + bool found;
> +};
> +
> +static int acpi_i2c_find_child_address(struct acpi_resource *ares, void *data)
> +{
> + struct acpi_resource_i2c_serialbus *sb;
> + struct acpi_i2c_find *i2c_find = data;
> +
> + if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
> + return 1;
> +
> + sb = &ares->data.i2c_serial_bus;
> + if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
> + return 1;
> +
> + if (sb->slave_address == i2c_find->addr)
> + i2c_find->found = true;
> +
> + return 1;
> +}
> +
> +static acpi_status acpi_i2c_find_child(acpi_handle handle, u32 level,
> + void *data, void **return_value)
> +{
> + struct acpi_i2c_find *i2c_find = data;
> + struct list_head resource_list;
> + 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;
> +
> + INIT_LIST_HEAD(&resource_list);
> + ret = acpi_dev_get_resources(adev, &resource_list,
> + acpi_i2c_find_child_address, i2c_find);
> + if (ret < 0)
> + return AE_OK;
> +
> + acpi_dev_free_resource_list(&resource_list);
> +
> + if (i2c_find->found) {
> + i2c_find->handle = handle;
> + return AE_CTRL_TERMINATE;
> + }
> + return AE_OK;
> +}
> +
> +static int acpi_i2c_find_device(struct device *dev, acpi_handle *handle)
> +{
> + struct acpi_i2c_find i2c_find;
> + struct i2c_adapter *adapter;
> + struct i2c_client *client;
> + acpi_handle parent;
> + acpi_status status;
> +
> + client = i2c_verify_client(dev);
> + if (!client)
> + return -ENODEV;
> +
> + adapter = client->adapter;
> + if (!adapter)
> + return -ENODEV;
> +
> + parent = adapter->dev.acpi_handle;
> + if (!parent)
> + return -ENODEV;
> +
> + memset(&i2c_find, 0, sizeof(i2c_find));
> + i2c_find.addr = client->addr;
> +
> + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, parent, 1,
> + acpi_i2c_find_child, NULL,
> + &i2c_find, NULL);
> + if (ACPI_FAILURE(status) || !i2c_find.handle)
> + return -ENODEV;
> +
> + *handle = i2c_find.handle;
> + return 0;
> +}
> +
> +static struct acpi_bus_type acpi_i2c_bus = {
> + .bus = &i2c_bus_type,
> + .find_device = acpi_i2c_find_device,
> +};
> +
> +void acpi_i2c_bus_register(void)
> +{
> + register_acpi_bus_type(&acpi_i2c_bus);
> +}
> +EXPORT_SYMBOL_GPL(acpi_i2c_bus_register);
> +
> +void acpi_i2c_bus_unregister(void)
> +{
> + unregister_acpi_bus_type(&acpi_i2c_bus);
> +}
> +EXPORT_SYMBOL_GPL(acpi_i2c_bus_unregister);
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index a7edf98..7385de2f 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -39,6 +39,8 @@
> #include <linux/irqflags.h>
> #include <linux/rwsem.h>
> #include <linux/pm_runtime.h>
> +#include <linux/acpi.h>
> +#include <linux/acpi_i2c.h>
> #include <asm/uaccess.h>
>
> #include "i2c-core.h"
> @@ -78,6 +80,10 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
> if (of_driver_match_device(dev, drv))
> return 1;
>
> + /* Then ACPI style match */
> + if (acpi_driver_match_device(dev, drv))
> + return 1;
> +
> driver = to_i2c_driver(drv);
> /* match on an id table if there is one */
> if (driver->id_table)
> @@ -1298,6 +1304,8 @@ static int __init i2c_init(void)
> retval = i2c_add_driver(&dummy_driver);
> if (retval)
> goto class_err;
> +
> + acpi_i2c_bus_register();
> return 0;
>
> class_err:
> @@ -1311,6 +1319,8 @@ bus_err:
>
> static void __exit i2c_exit(void)
> {
> + acpi_i2c_bus_unregister();
> +
> i2c_del_driver(&dummy_driver);
> #ifdef CONFIG_I2C_COMPAT
> class_compat_unregister(i2c_adapter_compat_class);
> diff --git a/include/linux/acpi_i2c.h b/include/linux/acpi_i2c.h
> new file mode 100644
> index 0000000..cf2233f
> --- /dev/null
> +++ b/include/linux/acpi_i2c.h
> @@ -0,0 +1,27 @@
> +/*
> + * 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.
> + */
> +
> +#ifndef LINUX_ACPI_I2C_H
> +#define LINUX_ACPI_I2C_H
> +
> +struct i2c_adapter;
> +
> +#if IS_ENABLED(CONFIG_ACPI_I2C)
> +extern void acpi_i2c_register_devices(struct i2c_adapter *adap);
> +extern void acpi_i2c_bus_register(void);
> +extern void acpi_i2c_bus_unregister(void);
> +#else
> +static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) {}
> +static inline void acpi_i2c_bus_register(void) {}
> +static inline void acpi_i2c_bus_unregister(void) {}
> +#endif /* IS_ENABLED(CONFIG_ACPI_I2C) */
> +
> +#endif /* LINUX_ACPI_I2C_H */
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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