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path: root/Documentation/spi/pxa2xx
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2007-04-21[ARM] 4304/1: removes the unnecessary bit number from CKENnn_XXXXEric Miao
This patch removes the unnecessary bit number from CKENnn_XXXX definitions for PXA, so that CKEN0_PWM0 --> CKEN_PWM0 CKEN1_PWM1 --> CKEN_PWM1 ... CKEN24_CAMERA --> CKEN_CAMERA The reasons for the change of these defitions are: 1. they do not scale - they are currently valid for pxa2xx, but definitely not valid for pxa3xx, e.g., pxa3xx has bit 3 for camera instead of bit 24 2. they are unnecessary - the peripheral name within the definition has already announced its usage, we don't need those bit numbers to know which peripheral we are going to enable/disable clock for 3. they are inconvenient - think about this: a driver programmer for pxa has to remember which bit in the CKEN register to turn on/off Another change in the patch is to make the definitions equal to its clock bit index, so that #define CKEN_CAMERA (24) instead of #define CKEN_CAMERA (1 << 24) this change, however, will add a run-time bit shift operation in pxa_set_cken(), but the benefit of this change is that it scales when bit index exceeds 32, e.g., pxa3xx has two registers CKENA and CKENB, totally 64 bit for this, suppose CAMERA clock enabling bit is CKENB:10, one can simply define CKEN_CAMERA to be (32 + 10) and so that pxa_set_cken() need minimum change to adapt to that. Signed-off-by: eric miao <eric.y.miao@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-10[PATCH] spi: stabilize PIO mode transfers on PXA2xx systemsStephen Street
Stabilize PIO mode transfers against a range of word sizes and FIFO thresholds and fixes word size setup/override issues. 1) 16 and 32 bit DMA/PIO transfers broken due to timing differences. 2) Potential for bad transfer counts due to transfer size assumptions. 3) Setup function broken is multiple ways. 4) Per transfer bit_per_word changes break DMA setup in pump_tranfers. 5) False positive timeout are not errors. 6) Changes in pxa2xx_spi_chip not effective in calls to setup. 7) Timeout scaling wrong for PXA255 NSSP. 8) Driver leaks memory while busy during unloading. Known issues: SPI_CS_HIGH and SPI_LSB_FIRST settings in struct spi_device are not handled. Testing: This patch has been test against the "random length, random bits/word, random data (verified on loopback) and stepped baud rate by octaves (3.6MHz to 115kHz)" test. It is robust in PIO mode, using any combination of tx and rx thresholds, and also in DMA mode (which internally computes the thresholds). Much thanks to Ned Forrester for exhaustive reviews, fixes and testing. The driver is substantially better for his efforts. Signed-off-by: Stephen Street <stephen@streetfiresound.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-03Documentation: remove duplicated wordsPaolo Ornati
Remove many duplicated words under Documentation/ and do other small cleanups. Examples: "and and" --> "and" "in in" --> "in" "the the" --> "the" "the the" --> "to the" ... Signed-off-by: Paolo Ornati <ornati@fastwebnet.it> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-05-16[PATCH] SPI: add PXA2xx SSP SPI DriverStephen Street
This driver turns a PXA2xx synchronous serial port (SSP) into a SPI master controller (see Documentation/spi/spi_summary). The driver has the following features: - Support for any PXA2xx SSP - SSP PIO and SSP DMA data transfers. - External and Internal (SSPFRM) chip selects. - Per slave device (chip) configuration. - Full suspend, freeze, resume support. Signed-off-by: Stephen Street <stephen@streetfiresound.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>