drm: panel: jd9365da-h3: fix reset signal polarity

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().

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@vger.kernel.org
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240927135306.857617-1-hugo@hugovil.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240927135306.857617-1-hugo@hugovil.com

diff --git a/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c b/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
index 45d09e6fa667fda925d2a1c67594af21b1982d5a..7d68a8acfe2ea45a913dff25eb5e9f0663503f08 100644 (file)
--- a/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
+++ b/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
@@ -109,13 +109,13 @@ 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);
@@ -1130,7 +1130,7 @@ 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);