[PATCH/RFC 6/6] spi: bcm2835: set gpio-cs to high state prior to any

Martin Sperl kernel at martin.sperl.org
Mon Mar 30 22:56:59 PDT 2015

> On 31.03.2015, at 05:35, Stephen Warren <swarren at wwwdotorg.org> wrote:
> I suspect the solution is simply not to have the pinctrl node set the CS
> pins to GPIO_OUT, but rather rely on gpio_request() ->
> bcm2835_gpio_request() -> bcm2835_pmx_gpio_set_direction() setting up
> the pinmux function for any GPIOs that are requested. Presumably, the CS
> GPIO for each chip is only requested when the DT node for the SPI device
> (not SPI controller device) has been parsed, so the correct GPIO CS
> value can be passed to gpio_request()/gpio_direction_output()?

I will investigate that and create a patch to spi_register_master that
does that for any GPIO-chipselect - this still leaves the question of
how to iterate over all the configured devices early to detect if they
hace cspol set and then setting it low instead of high.


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