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    SubjectRe: [PATCH v2 3/3] i2c / ACPI: add ACPI enumeration support
    Date
    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@linux.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@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/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@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.
    > + */
    > +
    > +#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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