diff options
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/Makefile | 3 | ||||
| -rw-r--r-- | drivers/base/devcon.c | 136 |
2 files changed, 138 insertions, 1 deletions
diff --git a/drivers/base/Makefile b/drivers/base/Makefile index e32a52490051..12a7f64d35a9 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -5,7 +5,8 @@ obj-y := component.o core.o bus.o dd.o syscore.o \ driver.o class.o platform.o \ cpu.o firmware.o init.o map.o devres.o \ attribute_container.o transport_class.o \ - topology.o container.o property.o cacheinfo.o + topology.o container.o property.o cacheinfo.o \ + devcon.o obj-$(CONFIG_DEVTMPFS) += devtmpfs.o obj-$(CONFIG_DMA_CMA) += dma-contiguous.o obj-y += power/ diff --git a/drivers/base/devcon.c b/drivers/base/devcon.c new file mode 100644 index 000000000000..d427e806cd73 --- /dev/null +++ b/drivers/base/devcon.c @@ -0,0 +1,136 @@ +// SPDX-License-Identifier: GPL-2.0 +/** + * Device connections + * + * Copyright (C) 2018 Intel Corporation + * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com> + */ + +#include <linux/device.h> + +static DEFINE_MUTEX(devcon_lock); +static LIST_HEAD(devcon_list); + +/** + * device_connection_find_match - Find physical connection to a device + * @dev: Device with the connection + * @con_id: Identifier for the connection + * @data: Data for the match function + * @match: Function to check and convert the connection description + * + * Find a connection with unique identifier @con_id between @dev and another + * device. @match will be used to convert the connection description to data the + * caller is expecting to be returned. + */ +void *device_connection_find_match(struct device *dev, const char *con_id, + void *data, + void *(*match)(struct device_connection *con, + int ep, void *data)) +{ + const char *devname = dev_name(dev); + struct device_connection *con; + void *ret = NULL; + int ep; + + if (!match) + return NULL; + + mutex_lock(&devcon_lock); + + list_for_each_entry(con, &devcon_list, list) { + ep = match_string(con->endpoint, 2, devname); + if (ep < 0) + continue; + + if (con_id && strcmp(con->id, con_id)) + continue; + + ret = match(con, !ep, data); + if (ret) + break; + } + + mutex_unlock(&devcon_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(device_connection_find_match); + +extern struct bus_type platform_bus_type; +extern struct bus_type pci_bus_type; +extern struct bus_type i2c_bus_type; +extern struct bus_type spi_bus_type; + +static struct bus_type *generic_match_buses[] = { + &platform_bus_type, +#ifdef CONFIG_PCI + &pci_bus_type, +#endif +#ifdef CONFIG_I2C + &i2c_bus_type, +#endif +#ifdef CONFIG_SPI_MASTER + &spi_bus_type, +#endif + NULL, +}; + +/* This tries to find the device from the most common bus types by name. */ +static void *generic_match(struct device_connection *con, int ep, void *data) +{ + struct bus_type *bus; + struct device *dev; + + for (bus = generic_match_buses[0]; bus; bus++) { + dev = bus_find_device_by_name(bus, NULL, con->endpoint[ep]); + if (dev) + return dev; + } + + /* + * We only get called if a connection was found, tell the caller to + * wait for the other device to show up. + */ + return ERR_PTR(-EPROBE_DEFER); +} + +/** + * device_connection_find - Find two devices connected together + * @dev: Device with the connection + * @con_id: Identifier for the connection + * + * Find a connection with unique identifier @con_id between @dev and + * another device. On success returns handle to the device that is connected + * to @dev, with the reference count for the found device incremented. Returns + * NULL if no matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a + * connection was found but the other device has not been enumerated yet. + */ +struct device *device_connection_find(struct device *dev, const char *con_id) +{ + return device_connection_find_match(dev, con_id, NULL, generic_match); +} +EXPORT_SYMBOL_GPL(device_connection_find); + +/** + * device_connection_add - Register a connection description + * @con: The connection description to be registered + */ +void device_connection_add(struct device_connection *con) +{ + mutex_lock(&devcon_lock); + list_add_tail(&con->list, &devcon_list); + mutex_unlock(&devcon_lock); +} +EXPORT_SYMBOL_GPL(device_connection_add); + +/** + * device_connections_remove - Unregister connection description + * @con: The connection description to be unregistered + */ +void device_connection_remove(struct device_connection *con) +{ + mutex_lock(&devcon_lock); + list_del(&con->list); + mutex_unlock(&devcon_lock); +} +EXPORT_SYMBOL_GPL(device_connection_remove); |