Re: [PATCH v2 01/12] drivers: base: Unified device connection lookup
On 02/25/2018 07:24 AM, Hans de Goede wrote: > From: Heikki Krogerus > > Several frameworks - clk, gpio, phy, pmw, etc. - maintain > lookup tables for describing connections and provide custom > API for handling them. This introduces a single generic > lookup table and API for the connections. > > The motivation for this commit is centralizing the > connection lookup, but the goal is to ultimately extract the > connection descriptions also from firmware by using the > fwnode_graph_* functions and other mechanisms that are > available. > > Signed-off-by: Heikki Krogerus > Reviewed-by: Hans de Goede > Signed-off-by: Hans de Goede > --- > Changes in v2: > -Add a (struct devcon) cast to the DEVCON() macro > --- > Documentation/driver-api/device_connection.rst | 43 > drivers/base/Makefile | 3 +- > drivers/base/devcon.c | 139 > + > include/linux/connection.h | 33 ++ > 4 files changed, 217 insertions(+), 1 deletion(-) > create mode 100644 Documentation/driver-api/device_connection.rst > create mode 100644 drivers/base/devcon.c > create mode 100644 include/linux/connection.h > > diff --git a/Documentation/driver-api/device_connection.rst > b/Documentation/driver-api/device_connection.rst > new file mode 100644 > index ..d52604448356 > --- /dev/null > +++ b/Documentation/driver-api/device_connection.rst > @@ -0,0 +1,43 @@ > +== > +Device connections > +== > + > +Introduction > + > + > +Devices have often connections to other devices that are out side of the > direct Devices often have connections are outside of > +child/parent relationship. A serial or network communication controller, > which > +could be a PCI device, may need to be able to get a reference to its PHY > +component, which could be attached to for example the I2C bus. Some device could be attached for example to the I2C bus. > +drivers need to be able to control the clocks or the GPIOs for their devices, > +and so on. > + > +Device connections are generic descriptions of any type of connection between > +two separate devices. > + > +Device connections alone do not create a dependency between the two devices. > +They are only descriptions which are not tied to either of devices directly. of the devices directly. > +A dependency between the two devices exists only if one of the two endpoint > +devices requests a reference to the other. The descriptions themselves can be > +defined in firmware (not yet supported) or they can be build-in. built-in. > + > +Usage > +- > + > +Device connections should exist before device ``->probe`` callback is called > for > +either endpoint devices in the description. If the connections are defined in device > +firmware, this is not a problem. It should be considered if the connection > +descriptions are "build-in", and need to be added separately. "built-in", > + > +The connection description consist of the names of the two devices with the consists > +connection, i.e. the endpoints, and unique identifier for the connection > which > +is needed if there are multiple connections between the two devices. > + > +After a descriptions exist, the devices in it can request reference to the > other description exists, > +endpoint device, or they can request the description itself. > + > +API > +--- > + > +.. kernel-doc:: drivers/base/devcon.c > + : functions: __device_find_connection device_find_connection > add_device_connection remove_device_connection > diff --git a/drivers/base/devcon.c b/drivers/base/devcon.c > new file mode 100644 > index ..6f9e4f7280a5 > --- /dev/null > +++ b/drivers/base/devcon.c > @@ -0,0 +1,139 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/** > + * Device connections > + * > + * Copyright (C) 2018 Intel Corporation > + * Author: Heikki Krogerus > + */ > + > +#include > +#include > + > +static DEFINE_MUTEX(devcon_lock); > +static LIST_HEAD(devcon_list); > + > +/** > + * __device_find_connection - 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 an other another > + * device. @match will be used to convert the connection description to data > the > + * caller is expecting to be returned. > + */ > +void *__device_find_connection(struct device *dev, const char *con_id, > +void *data, >
[PATCH v2 01/12] drivers: base: Unified device connection lookup
From: Heikki Krogerus Several frameworks - clk, gpio, phy, pmw, etc. - maintain lookup tables for describing connections and provide custom API for handling them. This introduces a single generic lookup table and API for the connections. The motivation for this commit is centralizing the connection lookup, but the goal is to ultimately extract the connection descriptions also from firmware by using the fwnode_graph_* functions and other mechanisms that are available. Signed-off-by: Heikki Krogerus Reviewed-by: Hans de Goede Signed-off-by: Hans de Goede --- Changes in v2: -Add a (struct devcon) cast to the DEVCON() macro --- Documentation/driver-api/device_connection.rst | 43 drivers/base/Makefile | 3 +- drivers/base/devcon.c | 139 + include/linux/connection.h | 33 ++ 4 files changed, 217 insertions(+), 1 deletion(-) create mode 100644 Documentation/driver-api/device_connection.rst create mode 100644 drivers/base/devcon.c create mode 100644 include/linux/connection.h diff --git a/Documentation/driver-api/device_connection.rst b/Documentation/driver-api/device_connection.rst new file mode 100644 index ..d52604448356 --- /dev/null +++ b/Documentation/driver-api/device_connection.rst @@ -0,0 +1,43 @@ +== +Device connections +== + +Introduction + + +Devices have often connections to other devices that are out side of the direct +child/parent relationship. A serial or network communication controller, which +could be a PCI device, may need to be able to get a reference to its PHY +component, which could be attached to for example the I2C bus. Some device +drivers need to be able to control the clocks or the GPIOs for their devices, +and so on. + +Device connections are generic descriptions of any type of connection between +two separate devices. + +Device connections alone do not create a dependency between the two devices. +They are only descriptions which are not tied to either of devices directly. +A dependency between the two devices exists only if one of the two endpoint +devices requests a reference to the other. The descriptions themselves can be +defined in firmware (not yet supported) or they can be build-in. + +Usage +- + +Device connections should exist before device ``->probe`` callback is called for +either endpoint devices in the description. If the connections are defined in +firmware, this is not a problem. It should be considered if the connection +descriptions are "build-in", and need to be added separately. + +The connection description consist of the names of the two devices with the +connection, i.e. the endpoints, and unique identifier for the connection which +is needed if there are multiple connections between the two devices. + +After a descriptions exist, the devices in it can request reference to the other +endpoint device, or they can request the description itself. + +API +--- + +.. kernel-doc:: drivers/base/devcon.c + : functions: __device_find_connection device_find_connection add_device_connection remove_device_connection 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 ..6f9e4f7280a5 --- /dev/null +++ b/drivers/base/devcon.c @@ -0,0 +1,139 @@ +// SPDX-License-Identifier: GPL-2.0 +/** + * Device connections + * + * Copyright (C) 2018 Intel Corporation + * Author: Heikki Krogerus + */ + +#include +#include + +static DEFINE_MUTEX(devcon_lock); +static LIST_HEAD(devcon_list); + +/** + * __device_find_connection - 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 an other + * device. @match will be used to convert the connection description to data the + * caller is expecting to be returned. + */ +void *__device_find_connection(struct device *dev, const char *con_id, + void *data, + void *(*match)(struct devcon *con, int e
