mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-08-24 01:41:39 +00:00
Code Issues Releases Wiki Activity

spi: davinci: add additional comments

Browse source 
Add comments describing the platform data members
and per-chip-select SPI configuration structure.

Also, add some comments describing the what happens
during the driver probe.

Signed-off-by: Brian Niebuhr <bniebuhr@efjohnson.com>
Tested-By: Michael Williamson <michael.williamson@criticallink.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
This commit is contained in:
Brian Niebuhr 2010-10-06 18:32:40 +05:30 committed by Sekhar Nori
parent d8c174cdeb
commit 035540f6ea
2 changed files with 39 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

32
arch/arm/mach-davinci/include/mach/spi.h
View file

@ -26,6 +26,20 @@ enum {
SPI_VERSION_2, /* For DA8xx */
};
/**
* davinci_spi_platform_data - Platform data for SPI master device on DaVinci
*
* @version: version of the SPI IP. Different DaVinci devices have slightly
* varying versions of the same IP.
* @num_chipselect: number of chipselects supported by this SPI master
* @intr_line: interrupt line used to connect the SPI IP to the ARM interrupt
* controller withn the SoC. Possible values are 0 and 1.
* @chip_sel: list of GPIOs which can act as chip-selects for the SPI.
* SPI_INTERN_CS denotes internal SPI chip-select. Not necessary
* to populate if all chip-selects are internal.
* @cshold_bug: set this to true if the SPI controller on your chip requires
* a write to CSHOLD bit in between transfers (like in DM355).
*/
struct davinci_spi_platform_data {
u8 version;
u8 num_chipselect;
@ -34,6 +48,24 @@ struct davinci_spi_platform_data {
bool cshold_bug;
};
/**
* davinci_spi_config - Per-chip-select configuration for SPI slave devices
*
* @wdelay: amount of delay between transmissions. Measured in number of
* SPI module clocks.
* @odd_parity: polarity of parity flag at the end of transmit data stream.
* 0 - odd parity, 1 - even parity.
* @parity_enable: enable transmission of parity at end of each transmit
* data stream.
* @io_type: type of IO transfer. Choose between polled, interrupt and DMA.
* @timer_disable: disable chip-select timers (setup and hold)
* @c2tdelay: chip-select setup time. Measured in number of SPI module clocks.
* @t2cdelay: chip-select hold time. Measured in number of SPI module clocks.
* @t2edelay: transmit data finished to SPI ENAn pin inactive time. Measured
* in number of SPI clocks.
* @c2edelay: chip-select active to SPI ENAn signal active time. Measured in
* number of SPI clocks.
*/
struct davinci_spi_config {
u8 wdelay;
u8 odd_parity;

7
drivers/spi/davinci_spi.c
View file

@ -787,6 +787,13 @@ static int davinci_spi_request_dma(struct davinci_spi *davinci_spi)
/**
* davinci_spi_probe - probe function for SPI Master Controller
* @pdev: platform_device structure which contains plateform specific data
*
* According to Linux Device Model this function will be invoked by Linux
* with platform_device struct which contains the device specific info.
* This function will map the SPI controller's memory, register IRQ,
* Reset SPI controller and setting its registers to default value.
* It will invoke spi_bitbang_start to create work queue so that client driver
* can register transfer method to work queue.
*/
static int davinci_spi_probe(struct platform_device *pdev)
{