Fix bug in unprepare() which causes the function's return value to be
that of the last mipi "enter sleep mode" command.

Update driver to use the "multi" variant of MIPI functions in order to
facilitate improved error handling and remove the panel's dependency on
deprecated MIPI functions.

Use the new mipi_dsi_dual macro to reduce code duplication.

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
Tested-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
Signed-off-by: Brigham Campbell <me@brighamcampbell.com>
---
 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c | 196 ++++++------------
 1 file changed, 59 insertions(+), 137 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c b/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
index 5f897e143758..83656bb4b0b2 100644
--- a/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
+++ b/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
@@ -81,25 +81,25 @@ static int jdi_panel_disable(struct drm_panel *panel)
 static int jdi_panel_unprepare(struct drm_panel *panel)
 {
 	struct jdi_panel *jdi = to_panel_jdi(panel);
-	int ret;
 
-	ret = mipi_dsi_dcs_set_display_off(jdi->link1);
-	if (ret < 0)
-		dev_err(panel->dev, "failed to set display off: %d\n", ret);
+	/*
+	 * One context per panel since we'll continue trying to shut down the
+	 * other panel even if one isn't responding.
+	 */
+	struct mipi_dsi_multi_context dsi_ctx1 = { .dsi = jdi->link1 };
+	struct mipi_dsi_multi_context dsi_ctx2 = { .dsi = jdi->link2 };
 
-	ret = mipi_dsi_dcs_set_display_off(jdi->link2);
-	if (ret < 0)
-		dev_err(panel->dev, "failed to set display off: %d\n", ret);
+	mipi_dsi_dcs_set_display_off_multi(&dsi_ctx1);
+	mipi_dsi_dcs_set_display_off_multi(&dsi_ctx2);
 
 	/* Specified by JDI @ 50ms, subject to change */
 	msleep(50);
 
-	ret = mipi_dsi_dcs_enter_sleep_mode(jdi->link1);
-	if (ret < 0)
-		dev_err(panel->dev, "failed to enter sleep mode: %d\n", ret);
-	ret = mipi_dsi_dcs_enter_sleep_mode(jdi->link2);
-	if (ret < 0)
-		dev_err(panel->dev, "failed to enter sleep mode: %d\n", ret);
+	/* Doesn't hurt to try sleep mode even if display off fails */
+	dsi_ctx1.accum_err = 0;
+	dsi_ctx2.accum_err = 0;
+	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx1);
+	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx2);
 
 	/* Specified by JDI @ 150ms, subject to change */
 	msleep(150);
@@ -123,72 +123,46 @@ static int jdi_panel_unprepare(struct drm_panel *panel)
 	/* Specified by JDI @ 20ms, subject to change */
 	msleep(20);
 
-	return ret;
-}
-
-static int jdi_setup_symmetrical_split(struct mipi_dsi_device *left,
-				       struct mipi_dsi_device *right,
-				       const struct drm_display_mode *mode)
-{
-	int err;
-
-	err = mipi_dsi_dcs_set_column_address(left, 0, mode->hdisplay / 2 - 1);
-	if (err < 0) {
-		dev_err(&left->dev, "failed to set column address: %d\n", err);
-		return err;
-	}
-
-	err = mipi_dsi_dcs_set_column_address(right, 0, mode->hdisplay / 2 - 1);
-	if (err < 0) {
-		dev_err(&right->dev, "failed to set column address: %d\n", err);
-		return err;
-	}
-
-	err = mipi_dsi_dcs_set_page_address(left, 0, mode->vdisplay - 1);
-	if (err < 0) {
-		dev_err(&left->dev, "failed to set page address: %d\n", err);
-		return err;
-	}
-
-	err = mipi_dsi_dcs_set_page_address(right, 0, mode->vdisplay - 1);
-	if (err < 0) {
-		dev_err(&right->dev, "failed to set page address: %d\n", err);
-		return err;
-	}
-
 	return 0;
 }
 
-static int jdi_write_dcdc_registers(struct jdi_panel *jdi)
+static void jdi_setup_symmetrical_split(struct mipi_dsi_multi_context *dsi_ctx,
+					struct mipi_dsi_device *left,
+					struct mipi_dsi_device *right,
+					const struct drm_display_mode *mode)
+{
+	mipi_dsi_dual(mipi_dsi_dcs_set_column_address_multi,
+		      dsi_ctx, left, right,
+		      0, mode->hdisplay / 2 - 1);
+	mipi_dsi_dual(mipi_dsi_dcs_set_page_address_multi,
+		      dsi_ctx, left, right,
+		      0, mode->vdisplay - 1);
+}
+
+static void jdi_write_dcdc_registers(struct mipi_dsi_multi_context *dsi_ctx,
+				     struct jdi_panel *jdi)
 {
 	/* Clear the manufacturer command access protection */
-	mipi_dsi_generic_write_seq(jdi->link1, MCS_CMD_ACS_PROT,
-				   MCS_CMD_ACS_PROT_OFF);
-	mipi_dsi_generic_write_seq(jdi->link2, MCS_CMD_ACS_PROT,
-				   MCS_CMD_ACS_PROT_OFF);
+	mipi_dsi_dual_generic_write_seq_multi(dsi_ctx, jdi->link1, jdi->link2,
+					      MCS_CMD_ACS_PROT,
+					      MCS_CMD_ACS_PROT_OFF);
 	/*
-	 * Change the VGH/VGL divide rations to move the noise generated by the
+	 * Change the VGH/VGL divide ratios to move the noise generated by the
 	 * TCONN. This should hopefully avoid interaction with the backlight
 	 * controller.
 	 */
-	mipi_dsi_generic_write_seq(jdi->link1, MCS_PWR_CTRL_FUNC,
-				   MCS_PWR_CTRL_PARAM1_VGH_330_DIV |
-				   MCS_PWR_CTRL_PARAM1_DEFAULT,
-				   MCS_PWR_CTRL_PARAM2_VGL_410_DIV |
-				   MCS_PWR_CTRL_PARAM2_DEFAULT);
-
-	mipi_dsi_generic_write_seq(jdi->link2, MCS_PWR_CTRL_FUNC,
-				   MCS_PWR_CTRL_PARAM1_VGH_330_DIV |
-				   MCS_PWR_CTRL_PARAM1_DEFAULT,
-				   MCS_PWR_CTRL_PARAM2_VGL_410_DIV |
-				   MCS_PWR_CTRL_PARAM2_DEFAULT);
-
-	return 0;
+	mipi_dsi_dual_generic_write_seq_multi(dsi_ctx, jdi->link1, jdi->link2,
+					      MCS_PWR_CTRL_FUNC,
+					      MCS_PWR_CTRL_PARAM1_VGH_330_DIV |
+					      MCS_PWR_CTRL_PARAM1_DEFAULT,
+					      MCS_PWR_CTRL_PARAM2_VGL_410_DIV |
+					      MCS_PWR_CTRL_PARAM2_DEFAULT);
 }
 
 static int jdi_panel_prepare(struct drm_panel *panel)
 {
 	struct jdi_panel *jdi = to_panel_jdi(panel);
+	struct mipi_dsi_multi_context dsi_ctx = {};
 	int err;
 
 	/* Disable backlight to avoid showing random pixels
@@ -231,88 +205,36 @@ static int jdi_panel_prepare(struct drm_panel *panel)
 	 * put in place to communicate the configuration back to the DSI host
 	 * controller.
 	 */
-	err = jdi_setup_symmetrical_split(jdi->link1, jdi->link2,
-					  jdi->mode);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to set up symmetrical split: %d\n",
-			err);
-		goto poweroff;
-	}
+	jdi_setup_symmetrical_split(&dsi_ctx, jdi->link1, jdi->link2,
+				    jdi->mode);
 
-	err = mipi_dsi_dcs_set_tear_scanline(jdi->link1,
-					     jdi->mode->vdisplay - 16);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to set tear scanline: %d\n", err);
-		goto poweroff;
-	}
+	mipi_dsi_dual(mipi_dsi_dcs_set_tear_scanline_multi,
+		      &dsi_ctx, jdi->link1, jdi->link2,
+		      jdi->mode->vdisplay - 16);
 
-	err = mipi_dsi_dcs_set_tear_scanline(jdi->link2,
-					     jdi->mode->vdisplay - 16);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to set tear scanline: %d\n", err);
-		goto poweroff;
-	}
+	mipi_dsi_dual(mipi_dsi_dcs_set_tear_on_multi,
+		      &dsi_ctx, jdi->link1, jdi->link2,
+		      MIPI_DSI_DCS_TEAR_MODE_VBLANK);
 
-	err = mipi_dsi_dcs_set_tear_on(jdi->link1,
-				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to set tear on: %d\n", err);
-		goto poweroff;
-	}
+	mipi_dsi_dual(mipi_dsi_dcs_set_pixel_format_multi,
+		      &dsi_ctx, jdi->link1, jdi->link2,
+		      MIPI_DCS_PIXEL_FMT_24BIT);
 
-	err = mipi_dsi_dcs_set_tear_on(jdi->link2,
-				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to set tear on: %d\n", err);
-		goto poweroff;
-	}
+	mipi_dsi_dual(mipi_dsi_dcs_exit_sleep_mode_multi,
+		      &dsi_ctx, jdi->link1, jdi->link2);
 
-	err = mipi_dsi_dcs_set_pixel_format(jdi->link1, MIPI_DCS_PIXEL_FMT_24BIT);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to set pixel format: %d\n", err);
-		goto poweroff;
-	}
-
-	err = mipi_dsi_dcs_set_pixel_format(jdi->link2, MIPI_DCS_PIXEL_FMT_24BIT);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to set pixel format: %d\n", err);
-		goto poweroff;
-	}
-
-	err = mipi_dsi_dcs_exit_sleep_mode(jdi->link1);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
-		goto poweroff;
-	}
-
-	err = mipi_dsi_dcs_exit_sleep_mode(jdi->link2);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
-		goto poweroff;
-	}
-
-	err = jdi_write_dcdc_registers(jdi);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to write dcdc registers: %d\n", err);
-		goto poweroff;
-	}
+	jdi_write_dcdc_registers(&dsi_ctx, jdi);
 	/*
-	 * We need to wait 150ms between mipi_dsi_dcs_exit_sleep_mode() and
-	 * mipi_dsi_dcs_set_display_on().
+	 * We need to wait 150ms between mipi_dsi_dcs_exit_sleep_mode_multi()
+	 * and mipi_dsi_dcs_set_display_on_multi().
 	 */
-	msleep(150);
+	mipi_dsi_msleep(&dsi_ctx, 150);
 
-	err = mipi_dsi_dcs_set_display_on(jdi->link1);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to set display on: %d\n", err);
-		goto poweroff;
-	}
+	mipi_dsi_dual(mipi_dsi_dcs_set_display_on_multi,
+		      &dsi_ctx, jdi->link1, jdi->link2);
 
-	err = mipi_dsi_dcs_set_display_on(jdi->link2);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to set display on: %d\n", err);
+	if (dsi_ctx.accum_err < 0)
 		goto poweroff;
-	}
 
 	jdi->link1->mode_flags &= ~MIPI_DSI_MODE_LPM;
 	jdi->link2->mode_flags &= ~MIPI_DSI_MODE_LPM;
-- 
2.50.1

Hi,

On Mon, Jul 21, 2025 at 6:53 PM Brigham Campbell <me@brighamcampbell.com> wrote:
>
> Fix bug in unprepare() which causes the function's return value to be
> that of the last mipi "enter sleep mode" command.
>
> Update driver to use the "multi" variant of MIPI functions in order to
> facilitate improved error handling and remove the panel's dependency on
> deprecated MIPI functions.
>
> Use the new mipi_dsi_dual macro to reduce code duplication.
>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> Reviewed-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
> Tested-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
> Signed-off-by: Brigham Campbell <me@brighamcampbell.com>
> ---
>  drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c | 196 ++++++------------
>  1 file changed, 59 insertions(+), 137 deletions(-)

Just for fun, I ran bloat-o-meter to compare before and after.

add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-217 (-217)
Function                                     old     new   delta
jdi_write_dcdc_registers.d                    10       5      -5
jdi_panel_unprepare                          312     260     -52
jdi_panel_prepare                           1020     860    -160
Total: Before=4908, After=4691, chg -4.42%

...not as big of a savings, but that's not too surprising in this case
since we don't have the whole pile of "seq" functions. Still the point
was making the driver cleaner and the space savings is just an extra
bonus!

-Doug