From 8ae12a0d85987dc138f8c944cb78a92bf466cea0 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Sun, 8 Jan 2006 13:34:19 -0800 Subject: [PATCH] spi: simple SPI framework This is the core of a small SPI framework, implementing the model of a queue of messages which complete asynchronously (with thin synchronous wrappers on top). - It's still less than 2KB of ".text" (ARM). If there's got to be a mid-layer for something so simple, that's the right size budget. :) - The guts use board-specific SPI device tables to build the driver model tree. (Hardware probing is rarely an option.) - This version of Kconfig includes no drivers. At this writing there are two known master controller drivers (PXA/SSP, OMAP MicroWire) and three protocol drivers (CS8415a, ADS7846, DataFlash) with LKML mentions of other drivers in development. - No userspace API. There are several implementations to compare. Implement them like any other driver, and bind them with sysfs. The changes from last version posted to LKML (on 11-Nov-2005) are minor, and include: - One bugfix (removes a FIXME), with the visible effect of making device names be "spiB.C" where B is the bus number and C is the chipselect. - The "caller provides DMA mappings" mechanism now has kerneldoc, for DMA drivers that want to be fancy. - Hey, the framework init can be subsys_init. Even though board init logic fires earlier, at arch_init ... since the framework init is for driver support, and the board init support uses static init. - Various additional spec/doc clarifications based on discussions with other folk. It adds a brief "thank you" at the end, for folk who've helped nudge this framework into existence. As I've said before, I think that "protocol tweaking" is the main support that this driver framework will need to evolve. From: Mark Underwood Update the SPI framework to remove a potential priority inversion case by reverting to kmalloc if the pre-allocated DMA-safe buffer isn't available. Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- drivers/spi/Kconfig | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 drivers/spi/Kconfig (limited to 'drivers/spi/Kconfig') diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig new file mode 100644 index 000000000000..d3105104a297 --- /dev/null +++ b/drivers/spi/Kconfig @@ -0,0 +1,76 @@ +# +# SPI driver configuration +# +# NOTE: the reason this doesn't show SPI slave support is mostly that +# nobody's needed a slave side API yet. The master-role API is not +# fully appropriate there, so it'd need some thought to do well. +# +menu "SPI support" + +config SPI + bool "SPI support" + help + The "Serial Peripheral Interface" is a low level synchronous + protocol. Chips that support SPI can have data transfer rates + up to several tens of Mbit/sec. Chips are addressed with a + controller and a chipselect. Most SPI slaves don't support + dynamic device discovery; some are even write-only or read-only. + + SPI is widely used by microcontollers to talk with sensors, + eeprom and flash memory, codecs and various other controller + chips, analog to digital (and d-to-a) converters, and more. + MMC and SD cards can be accessed using SPI protocol; and for + DataFlash cards used in MMC sockets, SPI must always be used. + + SPI is one of a family of similar protocols using a four wire + interface (select, clock, data in, data out) including Microwire + (half duplex), SSP, SSI, and PSP. This driver framework should + work with most such devices and controllers. + +config SPI_DEBUG + boolean "Debug support for SPI drivers" + depends on SPI && DEBUG_KERNEL + help + Say "yes" to enable debug messaging (like dev_dbg and pr_debug), + sysfs, and debugfs support in SPI controller and protocol drivers. + +# +# MASTER side ... talking to discrete SPI slave chips including microcontrollers +# + +config SPI_MASTER +# boolean "SPI Master Support" + boolean + default SPI + help + If your system has an master-capable SPI controller (which + provides the clock and chipselect), you can enable that + controller and the protocol drivers for the SPI slave chips + that are connected. + +comment "SPI Master Controller Drivers" + depends on SPI_MASTER + + +# +# Add new SPI master controllers in alphabetical order above this line +# + + +# +# There are lots of SPI device types, with sensors and memory +# being probably the most widely used ones. +# +comment "SPI Protocol Masters" + depends on SPI_MASTER + + +# +# Add new SPI protocol masters in alphabetical order above this line +# + + +# (slave support would go here) + +endmenu # "SPI support" + -- cgit v1.2.3