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drm/panel: waveshare: Add automatic panel recognition for DSI panels #7553

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47827d7
drm/panel: waveshare: Add automatic panel recognition support
EngineerWill Aug 13, 2026
42e7f15
ARM: dts: overlays: waveshare-dsi: Add auto_rec panel option
EngineerWill Aug 13, 2026
63338cb
Merge pull request #3 from EngineerWill/waveshare-dsi
EngineerWill Aug 13, 2026
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2 changes: 2 additions & 0 deletions arch/arm/boot/dts/overlays/README
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Original file line number Diff line number Diff line change
Expand Up @@ -6069,6 +6069,8 @@ Params: 2_8_inch 2.8" 480x640
11_9_inch 11.9" 320x1480
13_3_inch_4lane 13.3" 1920x1080 4lane
13_3_inch_2lane 13.3" 1920x1080 2lane
auto_rec Automatic panel recognition (1200x1920 or
1920x1200 at 30fps/60fps)
i2c1 Use i2c-1 with jumper wires from GPIOs 2&3
disable_touch Disable the touch controller
rotation Set the panel orientation property
Expand Down
3 changes: 3 additions & 0 deletions arch/arm/boot/dts/overlays/vc4-kms-dsi-waveshare-panel-overlay.dts
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Original file line number Diff line number Diff line change
Expand Up @@ -136,6 +136,9 @@
7_0_inchH = <&panel>, "compatible=waveshare,7.0inch-h-panel",
<&touch>, "touchscreen-swapped-x-y?",
<&touch>, "touchscreen-inverted-x?";
auto_rec = <&panel>, "compatible=waveshare,automatic-recognition-panel",
<&touch>, "touchscreen-swapped-x-y?",
<&touch>, "touchscreen-inverted-x?";
i2c1 = <&i2c_frag>, "target:0=",<&i2c1>,
<0>, "-3-4+5";
disable_touch = <&touch>, "status=disabled";
Expand Down
147 changes: 141 additions & 6 deletions drivers/gpu/drm/panel/panel-waveshare-dsi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,7 @@ struct ws_panel {
struct i2c_client *i2c;
const struct drm_display_mode *mode;
enum drm_panel_orientation orientation;
int lanes;
};

struct ws_panel_data {
Expand Down Expand Up @@ -345,6 +346,63 @@ static const struct ws_panel_data ws_panel_7_0_h_data = {
.mode_flags = MIPI_DSI_MODE_VIDEO_HSE | MIPI_DSI_MODE_VIDEO | MIPI_DSI_CLOCK_NON_CONTINUOUS,
};

/* 10.1inch DSI LCD (E)
* https://www.waveshare.com/10.1inch-dsi-lcd-e.htm
*/
static const struct drm_display_mode ws_panel_1200x1920_60fps_mode = {
.clock = 166666,
.hdisplay = 1200,
.hsync_start = 1200 + 28,
.hsync_end = 1200 + 28 + 10,
.htotal = 1200 + 28 + 10 + 30,
.vdisplay = 1920,
.vsync_start = 1920 + 238,
.vsync_end = 1920 + 238 + 4,
.vtotal = 1920 + 238 + 4 + 28,
};

static const struct drm_display_mode ws_panel_1200x1920_30fps_mode = {
.clock = 83333,
.hdisplay = 1200,
.hsync_start = 1200 + 28,
.hsync_end = 1200 + 28 + 10,
.htotal = 1200 + 28 + 10 + 30,
.vdisplay = 1920,
.vsync_start = 1920 + 238,
.vsync_end = 1920 + 238 + 4,
.vtotal = 1920 + 238 + 4 + 28,
};

static const struct drm_display_mode ws_panel_1920x1200_60fps_mode = {
.clock = 166666,
.hdisplay = 1920,
.hsync_start = 1920 + 238,
.hsync_end = 1920 + 238 + 4,
.htotal = 1920 + 238 + 4 + 28,
.vdisplay = 1200,
.vsync_start = 1200 + 28,
.vsync_end = 1200 + 28 + 10,
.vtotal = 1200 + 28 + 10 + 30,
};

static const struct drm_display_mode ws_panel_1920x1200_30fps_mode = {
.clock = 83333,
.hdisplay = 1920,
.hsync_start = 1920 + 238,
.hsync_end = 1920 + 238 + 4,
.htotal = 1920 + 238 + 4 + 28,
.vdisplay = 1200,
.vsync_start = 1200 + 28,
.vsync_end = 1200 + 28 + 10,
.vtotal = 1200 + 28 + 10 + 30,
};

static const struct ws_panel_data ws_panel_automatic_data = {
.mode = NULL,
.lanes = 0,
.mode_flags = MIPI_DSI_MODE_VIDEO_HSE | MIPI_DSI_MODE_VIDEO | MIPI_DSI_CLOCK_NON_CONTINUOUS,
};

static struct ws_panel *panel_to_ts(struct drm_panel *panel)
{
return container_of(panel, struct ws_panel, base);
Expand All @@ -359,6 +417,68 @@ static void ws_panel_i2c_write(struct ws_panel *ts, u8 reg, u8 val)
dev_err(&ts->i2c->dev, "I2C write failed: %d\n", ret);
}

static int ws_panel_i2c_read(struct ws_panel *ts, u8 reg)
{
int ret;

ret = i2c_smbus_read_byte_data(ts->i2c, reg);
if (ret < 0)
dev_err(&ts->i2c->dev, "read reg 0x%02x failed %d\n", reg, ret);
return ret;
}

static int ws_panel_auto_detect(struct ws_panel *ts)
{
int screen_type;
int rotate;
int fps;

fps = ws_panel_i2c_read(ts, 0xd0);
if (fps < 0)
return fps;

rotate = ws_panel_i2c_read(ts, 0xd1);
if (rotate < 0)
return rotate;

screen_type = ws_panel_i2c_read(ts, 0xd3);
if (screen_type < 0)
return screen_type;

dev_info(&ts->i2c->dev,
"automatic panel detect screen_type=0x%x rotate=0x%x fps=0x%x\n",
screen_type, rotate, fps);

if (screen_type == 0x01) {
switch (rotate) {
case 0:
case 2:
dev_info(&ts->i2c->dev, "select 1200x1920 panel\n");
ts->mode = fps == 60 ?
&ws_panel_1200x1920_60fps_mode :
&ws_panel_1200x1920_30fps_mode;
break;
case 1:
case 3:
dev_info(&ts->i2c->dev, "select 1920x1200 panel\n");
ts->mode = fps == 60 ?
&ws_panel_1920x1200_60fps_mode :
&ws_panel_1920x1200_30fps_mode;
break;
default:
dev_err(&ts->i2c->dev, "unknown rotate value %d\n", rotate);
return -EINVAL;
}
if (fps == 60)
ts->lanes = 4;
else
ts->lanes = 2;
return 0;
}
dev_err(&ts->i2c->dev, "unsupported panel D3=0x%x\n", screen_type);
return -EINVAL;
}

static int ws_panel_disable(struct drm_panel *panel)
{
struct ws_panel *ts = panel_to_ts(panel);
Expand Down Expand Up @@ -492,13 +612,24 @@ static int ws_panel_probe(struct i2c_client *i2c)
if (!_ws_panel_data)
return -EINVAL;

ts->mode = _ws_panel_data->mode;
if (!ts->mode)
return -EINVAL;

ts->i2c = i2c;
i2c_set_clientdata(i2c, ts);
ts->lanes = _ws_panel_data->lanes;
/*
* automatic recognition panel
*/
if (of_device_is_compatible(dev->of_node, "waveshare,automatic-recognition-panel")) {

@6by9 6by9 Aug 17, 2026

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You could simplify this to if (!_ws_panel_data->mode)

ret = ws_panel_auto_detect(ts);
if (ret) {
dev_err(dev, "panel auto detect failed\n");
return ret;
}
} else {
ts->mode = _ws_panel_data->mode;
}

ts->i2c = i2c;
if (!ts->mode)
return -EINVAL;

ws_panel_i2c_write(ts, 0xc0, 0x01);
ws_panel_i2c_write(ts, 0xc2, 0x01);
Expand Down Expand Up @@ -556,7 +687,7 @@ static int ws_panel_probe(struct i2c_client *i2c)

ts->dsi->mode_flags = _ws_panel_data->mode_flags;
ts->dsi->format = MIPI_DSI_FMT_RGB888;
ts->dsi->lanes = _ws_panel_data->lanes;
ts->dsi->lanes = ts->lanes;

ret = devm_mipi_dsi_attach(dev, ts->dsi);

Expand All @@ -583,6 +714,7 @@ static void ws_panel_shutdown(struct i2c_client *i2c)
{
struct ws_panel *ts = i2c_get_clientdata(i2c);

ws_panel_i2c_write(ts, 0xd2, 0x5a);

@6by9 6by9 Aug 17, 2026

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This seems odd as nothing else ever writes register 0xd2.

Note that shutdown is not called on remove. Should the device get unbound and rebound, then it won't get this write (whatever it does).

ws_panel_disable(&ts->base);
}

Expand Down Expand Up @@ -635,6 +767,9 @@ static const struct of_device_id ws_panel_of_ids[] = {
}, {
.compatible = "waveshare,7.0inch-h-panel",
.data = &ws_panel_7_0_h_data,
}, {
.compatible = "waveshare,automatic-recognition-panel",
.data = &ws_panel_automatic_data,
}, {
/* sentinel */
}
Expand Down
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