On Mon, May 24, 2021 at 2:41 PM Sander Vanheule <sander@xxxxxxxxxxxxx> wrote: > On Mon, 2021-05-24 at 10:53 +0300, Andy Shevchenko wrote: > > On Mon, May 24, 2021 at 4:11 AM Andrew Lunn <andrew@xxxxxxx> wrote: ... > > > > Changes since v2: > > > > - MDIO regmap support was merged, so patch is dropped here > > > > > > Do you have any idea how this will get merged. It sounds like one of > > > the Maintainers will need a stable branch of regmap. > > > > This is not a problem if Mark provides an immutable branch to pull from. > > Mark has a tag (regmap-mdio) for this patch: > https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git/tag/?h=regmap-mdio Also works but you have to provide this information in the cover letter. ... > > > > - Introduce GPIO regmap quirks to set output direction first > > > > > > I thought you had determined it was possible to set output before > > > direction? > > > > Same thoughts when I saw an updated version of that patch. My > > anticipation was to not see it at all. > > The two devices I've been trying to test the behaviour on are: > * Netgear GS110TPP: has an RTL8231 with three LEDs, each driven via a pin > configured as (active-low) GPIO. The LEDs are easy for a quick visual check. > * Zyxel GS1900-8: RTL8231 used for the front panel button, and an active-low > GPIO used to hard reset the main SoC (an RTL8380). I've modified this board > to change some of the strapping pin values, but testing with the jumpers and > pull-up/down resistors is a bit more tedious. > > On the Netgear, I tested the following with and without the quirk: > > # Set as OUT-LOW twice, to avoid the quirk. Always turns the LED on > gpioset 1 32=0; gpioset 1 32=0 > # Get value to change to input, turns the LED off (high impedance) > # Will return 1 due to (weak) internal pull-up > gpioget 1 32 > # Set as OUT-HIGH, should result in LED off > # When the quirk is disabled, the LED turns on (i.e. old OUT-LOW value) > # When the quirk is enabled, the LED remains off (i.e. correct OUT-HIGH value) > gpioset 1 32=1 > > Now, what's confusing (to me) is that the inverse doesn't depend on the quirk: > > # Set as OUT-HIGH twice > gpioset 1 32=1; gpioset 1 32=1 > # Change to high-Z > gpioget 1 32 > # Set to OUT-LOW, always results in LED on, with or without quirk > gpioset 1 32=0 > > Any idea why this would be (or appear) broken on the former case, but not on the > latter? GPIO tools for the shell are context-less. Can you reproduce this with the legacy sysfs interface? > I was trying to reproduce this behaviour on the Zyxel, but using the strapping > pins that are also used to configure the device's address. So perhaps the pull- > ups/-downs were confusing the results. Using a separate pin on the Zyxel's > RTL8231, I've now been able to confirm the same behaviour as on the Netgear, > including capturing the resulting glitch (with my simple logic analyser) when > enabling the quirk in the first test case. > > I hope this explains why I've still included the quirk in this revision. If not, > please let me know what isn't clear. Do you possess a schematic of either of the devices and a link to the RTL datasheet (Btw, if it's publicly available, or you have a link that will ask for necessary sign-in it would be nice to include the link to it as a Datasheet: tag)? -- With Best Regards, Andy Shevchenko
