Messages in this thread Patch in this message | | | From | Lee Jones <> | Subject | [PATCH 2/6] drivers/base: add bus for System-on-Chip devices | Date | Mon, 17 Oct 2011 12:52:54 +0100 |
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Traditionally, any System-on-Chip based platform creates a flat list of platform_devices directly under /sys/devices/platform.
In order to give these some better structure, this introduces a new bus type for soc_devices that are registered with the new soc_device_register() function. All devices that are on the same chip should then be registered as child devices of the soc device.
The soc bus also exports a few standardised device attributes which allow user space to query the specific type of soc.
Signed-off-by: Lee Jones <lee.jones@linaro.org> --- drivers/base/Kconfig | 3 + drivers/base/Makefile | 1 + drivers/base/soc.c | 115 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/sys_soc.h | 38 +++++++++++++++ 4 files changed, 157 insertions(+), 0 deletions(-) create mode 100644 drivers/base/soc.c create mode 100644 include/linux/sys_soc.h
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index 21cf46f..707aeaf 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -172,6 +172,9 @@ config SYS_HYPERVISOR bool default n +config SOC_BUS + bool + source "drivers/base/regmap/Kconfig" endmenu diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 99a375a..6b84b36 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -18,6 +18,7 @@ obj-$(CONFIG_MODULES) += module.o endif obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o obj-$(CONFIG_REGMAP) += regmap/ +obj-$(CONFIG_SOC_BUS) += soc.o ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG diff --git a/drivers/base/soc.c b/drivers/base/soc.c new file mode 100644 index 0000000..1578e4e --- /dev/null +++ b/drivers/base/soc.c @@ -0,0 +1,115 @@ +/* + * Copyright (C) ST-Ericsson SA 2011 + * + * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson. + * License terms: GNU General Public License (GPL), version 2 + */ + +#include <linux/sysfs.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/stat.h> +#include <linux/slab.h> +#include <linux/sys_soc.h> +#include <linux/err.h> + +static ssize_t soc_info_get(struct device *dev, + struct device_attribute *attr, + char *buf); + +static DEVICE_ATTR(machine, S_IRUGO, soc_info_get, NULL); +static DEVICE_ATTR(family, S_IRUGO, soc_info_get, NULL); +static DEVICE_ATTR(soc_id, S_IRUGO, soc_info_get, NULL); +static DEVICE_ATTR(revision, S_IRUGO, soc_info_get, NULL); + +static ssize_t soc_info_get(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct soc_device *soc_dev = + container_of(dev, struct soc_device, dev); + + if (attr == &dev_attr_machine) + return sprintf(buf, "%s\n", soc_dev->attr->machine); + if (attr == &dev_attr_family) + return sprintf(buf, "%s\n", soc_dev->attr->family); + if (attr == &dev_attr_revision) + return sprintf(buf, "%s\n", soc_dev->attr->revision); + if (attr == &dev_attr_soc_id) + return sprintf(buf, "%s\n", soc_dev->attr->soc_id); + + return -EINVAL; + +} + +struct bus_type soc_bus_type = { + .name = "soc", +}; + +static int __init soc_bus_register(void) +{ + return bus_register(&soc_bus_type); +} +core_initcall(soc_bus_register); + +struct attribute *soc_attr[] = { + &dev_attr_machine.attr, + &dev_attr_family.attr, + &dev_attr_soc_id.attr, + &dev_attr_revision.attr, + NULL, +}; + +struct attribute_group soc_attr_group = { + .attrs = soc_attr, +}; + +struct device *soc_device_register(struct soc_device_attribute *soc_dev_attr) +{ + struct soc_device *soc_dev; + static atomic_t soc_device_num = ATOMIC_INIT(0); + int ret; + + soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL); + if (!soc_dev) + return ERR_PTR(-ENOMEM); + + soc_dev->attr = soc_dev_attr; + soc_dev->dev.bus = &soc_bus_type; + + dev_set_name(&soc_dev->dev, "soc%d", + atomic_inc_return(&soc_device_num) - 1); + + ret = device_register(&soc_dev->dev); + if (ret) + goto out1; + + ret = sysfs_create_group(&soc_dev->dev.kobj, &soc_attr_group); + if (ret) + goto out2; + + return &soc_dev->dev; + +out2: + device_unregister(&soc_dev->dev); +out1: + kfree(soc_dev); + kfree(soc_dev->attr); + return ERR_PTR(ret); +} + +void soc_device_unregister(struct device *dev) +{ + struct soc_device *soc_dev = + container_of(dev, struct soc_device, dev); + + sysfs_remove_group(&dev->kobj, &soc_attr_group); + + if (device_is_registered(dev)) + device_unregister(dev); + + bus_unregister(&soc_bus_type); + + kfree(soc_dev->attr); + kfree(soc_dev); +} diff --git a/include/linux/sys_soc.h b/include/linux/sys_soc.h new file mode 100644 index 0000000..2485a0f2 --- /dev/null +++ b/include/linux/sys_soc.h @@ -0,0 +1,38 @@ +/* + * Copyright (C) ST-Ericsson SA 2011 + * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson. + * License terms: GNU General Public License (GPL), version 2 + */ +#ifndef __SOC_BUS_H +#define __SOC_BUS_H + +#include <linux/kobject.h> +#include <linux/device.h> +#include <linux/platform_device.h> + +struct soc_device_attribute { + const char *machine; + const char *family; + const char *revision; + const char *soc_id; +}; + +struct soc_device { + struct device dev; + struct soc_device_attribute *attr; +}; + +/** + * soc_device_register - register SoC as a device + * @soc_plat_dev_attr: Attributes passed from platform to be attributed to a SoC + */ +struct device *soc_device_register( + struct soc_device_attribute *soc_plat_dev_attr); + +/** + * soc_device_unregister - unregister SoC device + * @dev: SoC device to be unregistered + */ +void soc_device_unregister(struct device *dev); + +#endif /* __SOC_BUS_H */ -- 1.7.5.4
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