On Mon, 30 Sep 2024 18:24:44 +0200
neil.armstrong@xxxxxxxxxx wrote:
> On 30/09/2024 17:05, Hugo Villeneuve wrote:
> > On Mon, 30 Sep 2024 16:38:14 +0200
> > Neil Armstrong <neil.armstrong@xxxxxxxxxx> wrote:
> >
> >> Hi,
> >>
> >> On 27/09/2024 15:53, Hugo Villeneuve wrote:
> >>> From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
> >>>
> >>> In jadard_prepare() a reset pulse is generated with the following
> >>> statements (delays ommited for clarity):
> >>>
> >>> gpiod_set_value(jadard->reset, 1); --> Deassert reset
> >>> gpiod_set_value(jadard->reset, 0); --> Assert reset for 10ms
> >>> gpiod_set_value(jadard->reset, 1); --> Deassert reset
> >>>
> >>> However, specifying second argument of "0" to gpiod_set_value() means to
> >>> deassert the GPIO, and "1" means to assert it. If the reset signal is
> >>> defined as GPIO_ACTIVE_LOW in the DTS, the above statements will
> >>> incorrectly generate the reset pulse (inverted) and leave it asserted
> >>> (LOW) at the end of jadard_prepare().
> >>
> >> Did you check the polarity in DTS of _all_ users of this driver ?
> >
> > Hi Neil,
> > I confirmed that no in-tree DTS is referencing this driver. I did a
> > search of all the compatible strings defined in the
> > "jadard,jd9365da-h3.yaml" file. I also did the same on Debian code
> > search.
>
>
> OK then:
> Reviewed-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Hi Neil,
it seems this patch was never applied/picked-up?
Hugo.
>
> >
> > Hugo.
> >
> >
> >>
> >> Neil
> >>
> >>>
> >>> Fix reset behavior by inverting gpiod_set_value() second argument
> >>> in jadard_prepare(). Also modify second argument to devm_gpiod_get()
> >>> in jadard_dsi_probe() to assert the reset when probing.
> >>>
> >>> Do not modify it in jadard_unprepare() as it is already properly
> >>> asserted with "1", which seems to be the intended behavior.
> >>>
> >>> Fixes: 6b818c533dd8 ("drm: panel: Add Jadard JD9365DA-H3 DSI panel")
> >>> Cc: <stable@xxxxxxxxxxxxxxx>
> >>> Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
> >>> ---
> >>> drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c | 8 ++++----
> >>> 1 file changed, 4 insertions(+), 4 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c b/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
> >>> index 44897e5218a69..6fec99cf4d935 100644
> >>> --- a/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
> >>> +++ b/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
> >>> @@ -110,13 +110,13 @@ static int jadard_prepare(struct drm_panel *panel)
> >>> if (jadard->desc->lp11_to_reset_delay_ms)
> >>> msleep(jadard->desc->lp11_to_reset_delay_ms);
> >>>
> >>> - gpiod_set_value(jadard->reset, 1);
> >>> + gpiod_set_value(jadard->reset, 0);
> >>> msleep(5);
> >>>
> >>> - gpiod_set_value(jadard->reset, 0);
> >>> + gpiod_set_value(jadard->reset, 1);
> >>> msleep(10);
> >>>
> >>> - gpiod_set_value(jadard->reset, 1);
> >>> + gpiod_set_value(jadard->reset, 0);
> >>> msleep(130);
> >>>
> >>> ret = jadard->desc->init(jadard);
> >>> @@ -1131,7 +1131,7 @@ static int jadard_dsi_probe(struct mipi_dsi_device *dsi)
> >>> dsi->format = desc->format;
> >>> dsi->lanes = desc->lanes;
> >>>
> >>> - jadard->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> >>> + jadard->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> >>> if (IS_ERR(jadard->reset)) {
> >>> DRM_DEV_ERROR(&dsi->dev, "failed to get our reset GPIO\n");
> >>> return PTR_ERR(jadard->reset);
> >>>
> >>> base-commit: 18ba6034468e7949a9e2c2cf28e2e123b4fe7a50
> >>
> >>
> >
> >
>
>
--
Hugo Villeneuve
