Messages in this thread | | | From | Andy Shevchenko <> | Date | Mon, 24 Jul 2017 14:14:48 +0300 | Subject | Re: [PATCH] spi: pxa2xx: Only claim CS GPIOs when the slave device is created |
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On Mon, Jul 24, 2017 at 2:06 PM, Jan Kiszka <jan.kiszka@web.de> wrote: > On 2017-07-24 13:02, Andy Shevchenko wrote: >> On Mon, Jul 24, 2017 at 1:53 PM, Jan Kiszka <jan.kiszka@web.de> wrote: >>> On 2017-07-24 12:44, Andy Shevchenko wrote: >>>> +Cc: Mika >>>> >>>> On Sat, Jul 8, 2017 at 11:41 AM, Jan Kiszka <jan.kiszka@web.de> wrote: >>>>> From: Jan Kiszka <jan.kiszka@siemens.com> >>>>> >>>>> Avoid hogging chip select GPIOs just because they are listed for the >>>>> master. They might be mulitplexed and, if no slave device is attached, >>>>> used for different purposes. Moreover, this strategy avoids having to >>>>> allocate a cs_gpiods structure. >>>>> >>>>> Tested on the IOT2000 where the second SPI bus is connected to an >>>>> Arduino-compatible connector and multiplexed between SPI, GPIO and PWM >>>>> usage. >> >>>> This breaks all systems which are using _DSD. >>> >>> Err, can you elaborate? Worked fine here with _DSD on the IOT2000. >> >> Sure, the setup() function can be called several times for the same >> chip (as written in the comment inside the function). >> Definitely your code doesn't follow this, since gpiod_get_index() is >> returning -EBUSY when called 2+ time, that's what I got on all my >> tests. > > Ah, multiple devices on the same controller - I only had one.
Nope, one. Since we are talking about recurrent call to gpiod_get_index() with the same index.
-- With Best Regards, Andy Shevchenko
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