Re: [PATCH] drm: panel: jd9365da-h3: fix reset signal polarity

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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>


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








[Index of Archives]     [Linux DRI Users]     [Linux Intel Graphics]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux