diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-21 10:32:00 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-21 10:32:00 -0700 |
commit | 5f0e685f316a1de6d3af8b23eaf46651faca32ab (patch) | |
tree | af1ed231b7fcfc65b146be59a0aee699aa9f6353 /Documentation | |
parent | f8974cb71310a05632aada76be6a27576d61e609 (diff) | |
parent | 87bf5ab82884c829366914aaa813cc8b07b9fe58 (diff) | |
download | linux-5f0e685f316a1de6d3af8b23eaf46651faca32ab.tar.bz2 |
Merge tag 'spi-for-linus' of git://git.secretlab.ca/git/linux-2.6
Pull SPI changes for v3.4 from Grant Likely:
"Mostly a bunch of new drivers and driver bug fixes; but this also
includes a few patches that create a core message queue infrastructure
for the spi subsystem instead of making each driver open code it."
* tag 'spi-for-linus' of git://git.secretlab.ca/git/linux-2.6: (34 commits)
spi/fsl-espi: Make sure pm is within 2..32
spi/fsl-espi: make the clock computation easier to read
spi: sh-hspi: modify write/read method
spi: sh-hspi: control spi clock more correctly
spi: sh-hspi: convert to using core message queue
spi: s3c64xx: Fix build
spi: s3c64xx: remove unnecessary callback msg->complete
spi: remove redundant variable assignment
spi: release lock on error path in spi_pump_messages()
spi: Compatibility with direction which is used in samsung DMA operation
spi-topcliff-pch: add recovery processing in case wait-event timeout
spi-topcliff-pch: supports a spi mode setup and bit order setup by IO control
spi-topcliff-pch: Fix issue for transmitting over 4KByte
spi-topcliff-pch: Modify pci-bus number dynamically to get DMA device info
spi/imx: simplify error handling to free gpios
spi: Convert to DEFINE_PCI_DEVICE_TABLE
spi: add Broadcom BCM63xx SPI controller driver
SPI: add CSR SiRFprimaII SPI controller driver
spi-topcliff-pch: fix -Wuninitialized warning
spi: Mark spi_register_board_info() __devinit
...
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/devicetree/bindings/spi/omap-spi.txt | 20 | ||||
-rw-r--r-- | Documentation/spi/spi-summary | 58 |
2 files changed, 66 insertions, 12 deletions
diff --git a/Documentation/devicetree/bindings/spi/omap-spi.txt b/Documentation/devicetree/bindings/spi/omap-spi.txt new file mode 100644 index 000000000000..81df374adbb9 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/omap-spi.txt @@ -0,0 +1,20 @@ +OMAP2+ McSPI device + +Required properties: +- compatible : + - "ti,omap2-spi" for OMAP2 & OMAP3. + - "ti,omap4-spi" for OMAP4+. +- ti,spi-num-cs : Number of chipselect supported by the instance. +- ti,hwmods: Name of the hwmod associated to the McSPI + + +Example: + +mcspi1: mcspi@1 { + #address-cells = <1>; + #size-cells = <0>; + compatible = "ti,omap4-mcspi"; + ti,hwmods = "mcspi1"; + ti,spi-num-cs = <4>; +}; + diff --git a/Documentation/spi/spi-summary b/Documentation/spi/spi-summary index 4884cb33845d..7312ec14dd89 100644 --- a/Documentation/spi/spi-summary +++ b/Documentation/spi/spi-summary @@ -1,7 +1,7 @@ Overview of Linux kernel SPI support ==================================== -21-May-2007 +02-Feb-2012 What is SPI? ------------ @@ -483,9 +483,9 @@ also initialize its own internal state. (See below about bus numbering and those methods.) After you initialize the spi_master, then use spi_register_master() to -publish it to the rest of the system. At that time, device nodes for -the controller and any predeclared spi devices will be made available, -and the driver model core will take care of binding them to drivers. +publish it to the rest of the system. At that time, device nodes for the +controller and any predeclared spi devices will be made available, and +the driver model core will take care of binding them to drivers. If you need to remove your SPI controller driver, spi_unregister_master() will reverse the effect of spi_register_master(). @@ -521,21 +521,53 @@ SPI MASTER METHODS ** When you code setup(), ASSUME that the controller ** is actively processing transfers for another device. - master->transfer(struct spi_device *spi, struct spi_message *message) - This must not sleep. Its responsibility is arrange that the - transfer happens and its complete() callback is issued. The two - will normally happen later, after other transfers complete, and - if the controller is idle it will need to be kickstarted. - master->cleanup(struct spi_device *spi) Your controller driver may use spi_device.controller_state to hold state it dynamically associates with that device. If you do that, be sure to provide the cleanup() method to free that state. + master->prepare_transfer_hardware(struct spi_master *master) + This will be called by the queue mechanism to signal to the driver + that a message is coming in soon, so the subsystem requests the + driver to prepare the transfer hardware by issuing this call. + This may sleep. + + master->unprepare_transfer_hardware(struct spi_master *master) + This will be called by the queue mechanism to signal to the driver + that there are no more messages pending in the queue and it may + relax the hardware (e.g. by power management calls). This may sleep. + + master->transfer_one_message(struct spi_master *master, + struct spi_message *mesg) + The subsystem calls the driver to transfer a single message while + queuing transfers that arrive in the meantime. When the driver is + finished with this message, it must call + spi_finalize_current_message() so the subsystem can issue the next + transfer. This may sleep. + + DEPRECATED METHODS + + master->transfer(struct spi_device *spi, struct spi_message *message) + This must not sleep. Its responsibility is arrange that the + transfer happens and its complete() callback is issued. The two + will normally happen later, after other transfers complete, and + if the controller is idle it will need to be kickstarted. This + method is not used on queued controllers and must be NULL if + transfer_one_message() and (un)prepare_transfer_hardware() are + implemented. + SPI MESSAGE QUEUE -The bulk of the driver will be managing the I/O queue fed by transfer(). +If you are happy with the standard queueing mechanism provided by the +SPI subsystem, just implement the queued methods specified above. Using +the message queue has the upside of centralizing a lot of code and +providing pure process-context execution of methods. The message queue +can also be elevated to realtime priority on high-priority SPI traffic. + +Unless the queueing mechanism in the SPI subsystem is selected, the bulk +of the driver will be managing the I/O queue fed by the now deprecated +function transfer(). That queue could be purely conceptual. For example, a driver used only for low-frequency sensor access might be fine using synchronous PIO. @@ -561,4 +593,6 @@ Stephen Street Mark Underwood Andrew Victor Vitaly Wool - +Grant Likely +Mark Brown +Linus Walleij |