num_chipselect and number of Slaves

Hello,

Nothing serious, just a minor point to bring to your notice.

I came across a minor but confusing discrepancy in the documentation of SPI-API while writing a SPI controller driver.

include/linux/spi/spi.h defines num_chipselect as:- @num_chipselect: chipselects are used to distinguish individual SPI slaves, and are numbered from __zero-to-num_chipselects__.

Whereas drivers/spi/spi.c take them from [0, num_chipselect-1]

Perhaps thats why a couple of drivers fell for it.

drivers/spi/atmel_spi.c writes:-
"if (spi->chip_select > spi->master->num_chipselect)"
instead of
if (spi->chip_select >= spi->master->num_chipselect)

drivers/spi/spi_bfin5xx.c writes:-

    "(chip->chip_select_num <= spi->master->num_chipselect)"
instead of 
    (chip->chip_select_num < spi->master->num_chipselect)

Those concerned might like to make appropriate changes in the logic and documentation.

It's embarrassing to release a patch for such a trivial thing, or shud i? :)

Regards,
Jassi

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