On Wed, Apr 06, 2022 at 08:30:31AM -0700, Tim Harvey wrote: > On Wed, Apr 6, 2022 at 5:27 AM Tom Rini <[email protected]> wrote: > > > > On Wed, Mar 02, 2022 at 06:01:08PM -0800, Tim Harvey wrote: > > > > > A gpio-hog can be specified as output-low, output-high, or input where > > > output-low means 'de-asserted' and 'output-high' means asserted vs > > > voltage levels. > > > > > > When a hog is probed gpio_request_tail() calls dm_gpio_set_dir_flags() > > > which ends up setting the GPIO as an output with a driven 'de-asserted' > > > value prior to setting the desired value the hog was configured for. > > > While I'm not sure it makes sense to set the output level while simply > > > 'requesting' a GPIO the result of this is that if the hog is configured > > > for output-high the request call sets it first as output low before > > > gpio_hog_probe() sets it to the configured value causing the gpio to > > > 'glitch' which may be undesired for certain applications. > > > > > > Fix this by setting the GPIOD_IS_OUT_ACTIVE flag for hogs configured as > > > output-high. > > > > > > This was tested with the following hogs: > > > > > > /* active-high output-low (de-asserted) GPIO should drive 0 */ > > > gpio1 { > > > gpio-hog; > > > output-low; > > > gpios = <1 GPIO_ACTIVE_HIGH>; > > > line-name = "gpio1"; > > > }; > > > > > > /* active-high output-high (asserted) GPIO should drive 1 */ > > > /* before patch this would first drive 0 then 1 */ > > > gpio2 { > > > gpio-hog; > > > output-high; > > > gpios = <2 GPIO_ACTIVE_HIGH>; > > > line-name = "gpio2"; > > > }; > > > > > > /* active-low output-low (de-asserted) GPIO should drive 1 */ > > > gpio3 { > > > gpio-hog; > > > output-low; > > > gpios = <3 GPIO_ACTIVE_LOW>; > > > line-name = "gpio3#"; > > > }; > > > > > > /* active-low output-high (asserted) GPIO should drive 0 */ > > > /* before patch this would first drive 0 then 1 */ > > > gpio4 { > > > gpio-hog; > > > output-high; > > > gpios = <4 GPIO_ACTIVE_LOW>; > > > line-name = "gpio4#"; > > > }; > > > > > > Cc: Sean Anderson <[email protected]> > > > Signed-off-by: Tim Harvey <[email protected]> > > > > This breaks the ut_dm_dm_test_gpio test which I guess needs to be > > updated. > > > > Tom, > > That's kind of funny I suppose because the behavior is clearly wrong. > > Is fixing the test something that needs to be done for the patch to be > applied, or needs to be done by me? I'm not familiar with the test > framework or how to execute it.
For running the tests, please see: https://u-boot.readthedocs.io/en/latest/develop/testing.html and you're going to need to take a look at test/dm/gpio.c as where to fix what. And yes, a v2 that addresses the test as well is what I need. Thanks! -- Tom
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