diff options
author | David Woodhouse <David.Woodhouse@intel.com> | 2012-10-09 15:03:21 +0100 |
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committer | David Woodhouse <David.Woodhouse@intel.com> | 2012-10-09 15:04:25 +0100 |
commit | ffe315012510165ce82e4dd4767f0a5dba9edbf7 (patch) | |
tree | f601cd980af9d0ced5ca9aedecef4fa0d2ca0e15 /Documentation/smsc_ece1099.txt | |
parent | e2d3a35ee427aaba99b6c68a56609ce276c51270 (diff) | |
parent | 4a8e43feeac7996b8de2d5b2823e316917493df4 (diff) |
Merge tag 'disintegrate-mtd-20121009' of git://git.infradead.org/users/dhowells/linux-headers
UAPI Disintegration 2012-10-09
Conflicts:
MAINTAINERS
arch/arm/configs/bcmring_defconfig
arch/arm/mach-imx/clk-imx51-imx53.c
drivers/mtd/nand/Kconfig
drivers/mtd/nand/bcm_umi_nand.c
drivers/mtd/nand/nand_bcm_umi.h
drivers/mtd/nand/orion_nand.c
Diffstat (limited to 'Documentation/smsc_ece1099.txt')
-rw-r--r-- | Documentation/smsc_ece1099.txt | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/Documentation/smsc_ece1099.txt b/Documentation/smsc_ece1099.txt new file mode 100644 index 00000000000..6b492e82b43 --- /dev/null +++ b/Documentation/smsc_ece1099.txt @@ -0,0 +1,56 @@ +What is smsc-ece1099? +---------------------- + +The ECE1099 is a 40-Pin 3.3V Keyboard Scan Expansion +or GPIO Expansion device. The device supports a keyboard +scan matrix of 23x8. The device is connected to a Master +via the SMSC BC-Link interface or via the SMBus. +Keypad scan Input(KSI) and Keypad Scan Output(KSO) signals +are multiplexed with GPIOs. + +Interrupt generation +-------------------- + +Interrupts can be generated by an edge detection on a GPIO +pin or an edge detection on one of the bus interface pins. +Interrupts can also be detected on the keyboard scan interface. +The bus interrupt pin (BC_INT# or SMBUS_INT#) is asserted if +any bit in one of the Interrupt Status registers is 1 and +the corresponding Interrupt Mask bit is also 1. + +In order for software to determine which device is the source +of an interrupt, it should first read the Group Interrupt Status Register +to determine which Status register group is a source for the interrupt. +Software should read both the Status register and the associated Mask register, +then AND the two values together. Bits that are 1 in the result of the AND +are active interrupts. Software clears an interrupt by writing a 1 to the +corresponding bit in the Status register. + +Communication Protocol +---------------------- + +- SMbus slave Interface + The host processor communicates with the ECE1099 device + through a series of read/write registers via the SMBus + interface. SMBus is a serial communication protocol between + a computer host and its peripheral devices. The SMBus data + rate is 10KHz minimum to 400 KHz maximum + +- Slave Bus Interface + The ECE1099 device SMBus implementation is a subset of the + SMBus interface to the host. The device is a slave-only SMBus device. + The implementation in the device is a subset of SMBus since it + only supports four protocols. + + The Write Byte, Read Byte, Send Byte, and Receive Byte protocols are the + only valid SMBus protocols for the device. + +- BC-LinkTM Interface + The BC-Link is a proprietary bus that allows communication + between a Master device and a Companion device. The Master + device uses this serial bus to read and write registers + located on the Companion device. The bus comprises three signals, + BC_CLK, BC_DAT and BC_INT#. The Master device always provides the + clock, BC_CLK, and the Companion device is the source for an + independent asynchronous interrupt signal, BC_INT#. The ECE1099 + supports BC-Link speeds up to 24MHz. |