[PATCH v5 0/4] drm: Fix bug in panel driver, update MIPI support macros

[PATCH v5 0/4] drm: Fix bug in panel driver, update MIPI support macros

[Brigham Campbell]

This series removes the unintuitive mipi_dsi_generic_write_seq() macro
and related mipi_dsi_generic_write_chatty() method from the drm
subsystem. This is in accordance with a TODO item from Douglas Anderson
in the drm subsystem documentation. Tejas Vipin (among others) has
largely spearheaded this effort up until now, converting MIPI panel
drivers one at a time.

The second patch of the series removes the last remaining references to
mipi_dsi_generic_write_seq() in the jdi-lpm102a188a driver and updates
the driver to use the undeprecated _multi variants of MIPI functions. It
fixes a bug in the driver's unprepare function and cleans up duplicated
code using the new mipi_dsi_dual macro introduced in the first patch.

changes to v5:
 - Rework mipi_dsi_dual to explicitly not support passing macros into
   _func and add "dual" variants of the generic and dcs write macros.
 - Make jdi-lpm102a188a use the new
   mipi_dsi_dual_generic_write_seq_multi macro.
 - Make local struct variable in jdi-lpm102a188a conform to reverse
   christmas tree order.

changes to v4:
 - Fix whitespace (I forgot to run checkpatch. Thanks for your patience
   as I familiarize myself with the kernel development process)
 - Initialize mipi_dsi_multi_context struct

changes to v3:
 - Define new mipi_dsi_dual macro in drm_mipi_dsi.h to reduce code
   duplication.
 - Fix bug in lpm102a188a panel driver's unprepare function which causes
   it to return a nonsensical value.
 - Make lpm102a188a panel driver's unprepare function send "display off"
   and "enter sleep mode" commands to both serial interfaces regardless
   of whether an error occurred when sending the last command.

changes to v2:
 - Remove all usages of deprecated MIPI functions from jdi-lpm102a188a
   driver instead of just mipi_dsi_generic_write_seq().
 - Update TODO item in drm documentation instead of removing it
   entirely.

Brigham Campbell (4):
  drm: Create mipi_dsi_dual* macros
  drm/panel: jdi-lpm102a188a: Fix bug and clean up driver
  drm: Remove unused MIPI write seq and chatty functions
  drm: docs: Update task from drm TODO list

 Documentation/gpu/todo.rst                    |  22 +-
 drivers/gpu/drm/drm_mipi_dsi.c                |  82 +++++---
 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c | 196 ++++++------------
 include/drm/drm_mipi_dsi.h                    | 112 ++++++++--
 4 files changed, 210 insertions(+), 202 deletions(-)

v4: https://lore.kernel.org/all/20250717164053.284969-1-me@brighamcampbell.com/
v3: https://lore.kernel.org/all/20250717065757.246122-1-me@brighamcampbell.com/
v2: https://lore.kernel.org/all/20250708073901.90027-1-me@brighamcampbell.com/
v1: https://lore.kernel.org/all/20250707075659.75810-1-me@brighamcampbell.com/

base-commit: ca2a6abdaee43808034cdb218428d2ed85fd3db8

May you all have a wonderful weekend. I'll be riding my motorcycle up
Logan Canyon.
-- 
2.50.1

[PATCH v5 1/4] drm: Create mipi_dsi_dual* macros

[Brigham Campbell]

Create mipi_dsi_dual, mipi_dsi_dual_dcs_write_seq_multi, and
mipi_dsi_dual_generic_write_seq_multi macros for panels which are driven
by two parallel serial interfaces. This allows for the reduction of code
duplication in drivers for these panels.

Signed-off-by: Brigham Campbell <me@brighamcampbell.com>
---

mipi_dsi_dual_dcs_write_seq_multi goes unused by jdi-lpm102a188a. It's
included in this patch for completeness and in anticipation of its use
in other drivers in the future.

 drivers/gpu/drm/drm_mipi_dsi.c | 48 ++++++++++++++++++
 include/drm/drm_mipi_dsi.h     | 89 ++++++++++++++++++++++++++++++++++
 2 files changed, 137 insertions(+)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index a00d76443128..4a7ca1261105 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -827,6 +827,30 @@ void mipi_dsi_generic_write_multi(struct mipi_dsi_multi_context *ctx,
 }
 EXPORT_SYMBOL(mipi_dsi_generic_write_multi);
 
+/**
+ * mipi_dsi_dual_generic_write_multi() - mipi_dsi_generic_write_multi() for
+ * two dsi channels, one after the other
+ * @dsi1: First dsi channel to write buffer to
+ * @dsi2: Second dsi channel to write buffer to
+ * @ctx: Context for multiple DSI transactions
+ * @payload: Buffer containing the payload
+ * @size: Size of payload buffer
+ *
+ * A wrapper around mipi_dsi_generic_write_multi() that allows the user to
+ * conveniently write to two dsi channels, one after the other.
+ */
+void mpi_dsi_dual_generic_write_multi(struct mipi_dsi_device *dsi1,
+				      struct mipi_dsi_device *dsi2,
+				      struct mipi_dsi_multi_context *ctx,
+				      const void *payload, size_t size)
+{
+	ctx->dsi = dsi1;
+	mipi_dsi_generic_write_multi(ctx, data, len);
+	ctx->dsi = dsi2;
+	mipi_dsi_generic_write_multi(ctx, data, len);
+}
+EXPORT_SYMBOL(mipi_dsi_dual_generic_write_multi);
+
 /**
  * mipi_dsi_generic_read() - receive data using a generic read packet
  * @dsi: DSI peripheral device
@@ -1006,6 +1030,30 @@ void mipi_dsi_dcs_write_buffer_multi(struct mipi_dsi_multi_context *ctx,
 }
 EXPORT_SYMBOL(mipi_dsi_dcs_write_buffer_multi);
 
+/**
+ * mipi_dsi_dual_dcs_write_buffer_multi - mipi_dsi_dcs_write_buffer_multi() for
+ * two dsi channels, one after the other
+ * @dsi1: First dsi channel to write buffer to
+ * @dsi2: Second dsi channel to write buffer to
+ * @ctx: Context for multiple DSI transactions
+ * @data: Buffer containing data to be transmitted
+ * @len: Size of transmission buffer
+ *
+ * A wrapper around mipi_dsi_dcs_write_buffer_multi() that allows the user to
+ * conveniently write to two dsi channels, one after the other.
+ */
+void mipi_dsi_dual_dcs_write_buffer_multi(struct mipi_dsi_device *dsi1,
+					  struct mipi_dsi_device *dsi2,
+					  struct mipi_dsi_multi_context *ctx,
+					  const void *data, size_t len)
+{
+	ctx->dsi = dsi1;
+	mipi_dsi_dcs_write_buffer_multi(ctx, data, len);
+	ctx->dsi = dsi2;
+	mipi_dsi_dcs_write_buffer_multi(ctx, data, len);
+}
+EXPORT_SYMBOL(mipi_dsi_dual_dcs_write_buffer_multi);
+
 /**
  * mipi_dsi_dcs_write() - send DCS write command
  * @dsi: DSI peripheral device
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 369b0d8830c3..ffdfcb57cbd4 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -289,6 +289,10 @@ int mipi_dsi_generic_write_chatty(struct mipi_dsi_device *dsi,
 				  const void *payload, size_t size);
 void mipi_dsi_generic_write_multi(struct mipi_dsi_multi_context *ctx,
 				  const void *payload, size_t size);
+void mipi_dsi_dual_generic_write_multi(struct mipi_dsi_device *dsi1,
+				       struct mipi_dsi_device *dsi2,
+				       struct mipi_dsi_multi_context *ctx,
+				       const void *payload, size_t size);
 ssize_t mipi_dsi_generic_read(struct mipi_dsi_device *dsi, const void *params,
 			      size_t num_params, void *data, size_t size);
 u32 drm_mipi_dsi_get_input_bus_fmt(enum mipi_dsi_pixel_format dsi_format);
@@ -329,6 +333,10 @@ int mipi_dsi_dcs_write_buffer_chatty(struct mipi_dsi_device *dsi,
 				     const void *data, size_t len);
 void mipi_dsi_dcs_write_buffer_multi(struct mipi_dsi_multi_context *ctx,
 				     const void *data, size_t len);
+void mipi_dsi_dual_dcs_write_buffer_multi(struct mipi_dsi_device *dsi1,
+					  struct mipi_dsi_device *dsi2,
+					  struct mipi_dsi_multi_context *ctx,
+					  const void *data, size_t len);
 ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, u8 cmd,
 			   const void *data, size_t len);
 ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data,
@@ -431,6 +439,87 @@ void mipi_dsi_dcs_set_tear_off_multi(struct mipi_dsi_multi_context *ctx);
 		mipi_dsi_dcs_write_buffer_multi(ctx, d, ARRAY_SIZE(d)); \
 	} while (0)
 
+/**
+ * mipi_dsi_dual - send the same MIPI DSI command to two interfaces
+ *
+ * This macro will send the specified MIPI DSI command twice, once per each of
+ * the two interfaces supplied. This is useful for reducing duplication of code
+ * in panel drivers which use two parallel serial interfaces.
+ *
+ * WARNING: This macro reuses the _func argument and the optional trailing
+ * arguments twice each, which may cause unintended side effects. For example,
+ * adding the postfix increment ++ operator to one of the arguments to be
+ * passed to _func will cause the variable to be incremented twice instead of
+ * once and the variable will be its original value + 1 when sent to _dsi2.
+ *
+ * @_func: MIPI DSI function or macro to pass context and arguments into
+ * @_dsi1: First DSI interface to act as recipient of the MIPI DSI command
+ * @_dsi2: Second DSI interface to act as recipient of the MIPI DSI command
+ * @_ctx: Context for multiple DSI transactions
+ * @...: Arguments to pass to MIPI DSI function or macro
+ */
+#define mipi_dsi_dual(_func, _dsi1, _dsi2, _ctx, ...)		 \
+	do {							 \
+		struct mipi_dsi_multi_context *_ctxcpy = (_ctx); \
+		(_ctxcpy)->dsi = (_dsi1);			 \
+		(_func)((_ctxcpy), ##__VA_ARGS__);		 \
+		(_ctxcpy)->dsi = (_dsi2);			 \
+		(_func)((_ctxcpy), ##__VA_ARGS__);		 \
+	} while (0)
+
+/**
+ * mipi_dsi_dual_generic_write_seq_multi - transmit data using a generic write
+ * packet to two dsi interfaces, one after the other
+ *
+ * This macro will send the specified generic packet twice, once per each of
+ * the two interfaces supplied. This is useful for reducing duplication of code
+ * in panel drivers which use two parallel serial interfaces.
+ *
+ * Note that if an error occurs while transmitting the packet to the first DSI
+ * interface, the packet will not be sent to the second DSI interface.
+ *
+ * This macro will print errors for you and error handling is optimized for
+ * callers that call this multiple times in a row.
+ *
+ * @_dsi1: First DSI interface to act as recipient of packet
+ * @_dsi2: Second DSI interface to act as recipient of packet
+ * @_ctx: Context for multiple DSI transactions
+ * @_seq: buffer containing the payload
+ */
+#define mipi_dsi_dual_generic_write_seq_multi(_dsi1, _dsi2, _ctx, _seq...)	\
+	do {									\
+		static const u8 d[] = { _seq };					\
+		mipi_dsi_dual_generic_write_multi(_dsi1, _dsi2, _ctx, d,	\
+							 ARRAY_SIZE(d));	\
+	} while (0)
+
+/**
+ * mipi_dsi_dual_dcs_write_seq_multi - transmit a DCS command with payload to
+ * two dsi interfaces, one after the other
+ *
+ * This macro will send the specified DCS command with payload twice, once per
+ * each of the two interfaces supplied. This is useful for reducing duplication
+ * of code in panel drivers which use two parallel serial interfaces.
+ *
+ * Note that if an error occurs while transmitting the payload to the first DSI
+ * interface, the payload will not be sent to the second DSI interface.
+ *
+ * This macro will print errors for you and error handling is optimized for
+ * callers that call this multiple times in a row.
+ *
+ * @_dsi1: First DSI interface to act as recipient of packet
+ * @_dsi2: Second DSI interface to act as recipient of packet
+ * @_ctx: Context for multiple DSI transactions
+ * @_cmd: Command
+ * @_seq: buffer containing the payload
+ */
+#define mipi_dsi_dual_dcs_write_seq_multi(_dsi1, _dsi2, _ctx, _cmd, _seq)   \
+	do {								    \
+		static const u8 d[] = { _cmd, _seq };			    \
+		mipi_dsi_dual_dcs_write_buffer_multi(_dsi1, _dsi2, _ctx, d, \
+						     ARRAY_SIZE(d));	    \
+	} while (0)
+
 /**
  * struct mipi_dsi_driver - DSI driver
  * @driver: device driver model driver
-- 
2.50.1

[PATCH v5 2/4] drm/panel: jdi-lpm102a188a: Fix bug and clean up driver

[Brigham Campbell]

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..243483a58c45 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,
+		      left, right, dsi_ctx,
+		      0, mode->hdisplay / 2 - 1);
+	mipi_dsi_dual(mipi_dsi_dcs_set_page_address_multi,
+		      left, right, dsi_ctx,
+		      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(jdi->link1, jdi->link2, dsi_ctx,
+					      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(jdi->link1, jdi->link2, dsi_ctx,
+					      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,
+		      jdi->link1, jdi->link2, &dsi_ctx,
+		      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,
+		      jdi->link1, jdi->link2, &dsi_ctx,
+		      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,
+		      jdi->link1, jdi->link2, &dsi_ctx,
+		      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,
+		      jdi->link1, jdi->link2, &dsi_ctx);
 
-	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,
+		      jdi->link1, jdi->link2, &dsi_ctx);
 
-	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

[PATCH v5 3/4] drm: Remove unused MIPI write seq and chatty functions

[Brigham Campbell]

Remove the deprecated mipi_dsi_generic_write_seq() and
mipi_dsi_generic_write_chatty() functions now that they are no longer
used.

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Brigham Campbell <me@brighamcampbell.com>
---
 drivers/gpu/drm/drm_mipi_dsi.c | 34 +++-------------------------------
 include/drm/drm_mipi_dsi.h     | 23 -----------------------
 2 files changed, 3 insertions(+), 54 deletions(-)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index 4a7ca1261105..dff00d725236 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -772,41 +772,13 @@ ssize_t mipi_dsi_generic_write(struct mipi_dsi_device *dsi, const void *payload,
 EXPORT_SYMBOL(mipi_dsi_generic_write);
 
 /**
- * mipi_dsi_generic_write_chatty() - mipi_dsi_generic_write() w/ an error log
- * @dsi: DSI peripheral device
- * @payload: buffer containing the payload
- * @size: size of payload buffer
- *
- * Like mipi_dsi_generic_write() but includes a dev_err()
- * call for you and returns 0 upon success, not the number of bytes sent.
- *
- * Return: 0 on success or a negative error code on failure.
- */
-int mipi_dsi_generic_write_chatty(struct mipi_dsi_device *dsi,
-				  const void *payload, size_t size)
-{
-	struct device *dev = &dsi->dev;
-	ssize_t ret;
-
-	ret = mipi_dsi_generic_write(dsi, payload, size);
-	if (ret < 0) {
-		dev_err(dev, "sending generic data %*ph failed: %zd\n",
-			(int)size, payload, ret);
-		return ret;
-	}
-
-	return 0;
-}
-EXPORT_SYMBOL(mipi_dsi_generic_write_chatty);
-
-/**
- * mipi_dsi_generic_write_multi() - mipi_dsi_generic_write_chatty() w/ accum_err
+ * mipi_dsi_generic_write_multi() - mipi_dsi_generic_write() w/ accum_err
  * @ctx: Context for multiple DSI transactions
  * @payload: buffer containing the payload
  * @size: size of payload buffer
  *
- * Like mipi_dsi_generic_write_chatty() but deals with errors in a way that
- * makes it convenient to make several calls in a row.
+ * A wrapper around mipi_dsi_generic_write() that deals with errors in a way
+ * that makes it convenient to make several calls in a row.
  */
 void mipi_dsi_generic_write_multi(struct mipi_dsi_multi_context *ctx,
 				  const void *payload, size_t size)
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index ffdfcb57cbd4..528b5979ab8b 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -285,8 +285,6 @@ void mipi_dsi_picture_parameter_set_multi(struct mipi_dsi_multi_context *ctx,
 
 ssize_t mipi_dsi_generic_write(struct mipi_dsi_device *dsi, const void *payload,
 			       size_t size);
-int mipi_dsi_generic_write_chatty(struct mipi_dsi_device *dsi,
-				  const void *payload, size_t size);
 void mipi_dsi_generic_write_multi(struct mipi_dsi_multi_context *ctx,
 				  const void *payload, size_t size);
 void mipi_dsi_dual_generic_write_multi(struct mipi_dsi_device *dsi1,
@@ -387,27 +385,6 @@ void mipi_dsi_dcs_set_tear_scanline_multi(struct mipi_dsi_multi_context *ctx,
 					  u16 scanline);
 void mipi_dsi_dcs_set_tear_off_multi(struct mipi_dsi_multi_context *ctx);
 
-/**
- * mipi_dsi_generic_write_seq - transmit data using a generic write packet
- *
- * This macro will print errors for you and will RETURN FROM THE CALLING
- * FUNCTION (yes this is non-intuitive) upon error.
- *
- * Because of the non-intuitive return behavior, THIS MACRO IS DEPRECATED.
- * Please replace calls of it with mipi_dsi_generic_write_seq_multi().
- *
- * @dsi: DSI peripheral device
- * @seq: buffer containing the payload
- */
-#define mipi_dsi_generic_write_seq(dsi, seq...)                                \
-	do {                                                                   \
-		static const u8 d[] = { seq };                                 \
-		int ret;                                                       \
-		ret = mipi_dsi_generic_write_chatty(dsi, d, ARRAY_SIZE(d));    \
-		if (ret < 0)                                                   \
-			return ret;                                            \
-	} while (0)
-
 /**
  * mipi_dsi_generic_write_seq_multi - transmit data using a generic write packet
  *
-- 
2.50.1

[PATCH v5 4/4] drm: docs: Update task from drm TODO list

[Brigham Campbell]

Update TODO item from drm documentation to contain more applicable
information regarding the removal of deprecated MIPI DSI functions and
no longer reference functions which have already been removed from the
kernel.

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Brigham Campbell <me@brighamcampbell.com>
---
 Documentation/gpu/todo.rst | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index be8637da3fe9..92db80793bba 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -497,19 +497,19 @@ Contact: Douglas Anderson <dianders@chromium.org>
 
 Level: Intermediate
 
-Transition away from using mipi_dsi_*_write_seq()
--------------------------------------------------
+Transition away from using deprecated MIPI DSI functions
+--------------------------------------------------------
 
-The macros mipi_dsi_generic_write_seq() and mipi_dsi_dcs_write_seq() are
-non-intuitive because, if there are errors, they return out of the *caller's*
-function. We should move all callers to use mipi_dsi_generic_write_seq_multi()
-and mipi_dsi_dcs_write_seq_multi() macros instead.
+There are many functions defined in ``drm_mipi_dsi.c`` which have been
+deprecated. Each deprecated function was deprecated in favor of its `multi`
+variant (e.g. `mipi_dsi_generic_write()` and `mipi_dsi_generic_write_multi()`).
+The `multi` variant of a function includes improved error handling and logic
+which makes it more convenient to make several calls in a row, as most MIPI
+drivers do.
 
-Once all callers are transitioned, the macros and the functions that they call,
-mipi_dsi_generic_write_chatty() and mipi_dsi_dcs_write_buffer_chatty(), can
-probably be removed. Alternatively, if people feel like the _multi() variants
-are overkill for some use cases, we could keep the mipi_dsi_*_write_seq()
-variants but change them not to return out of the caller.
+Drivers should be updated to use undeprecated functions. Once all usages of the
+deprecated MIPI DSI functions have been removed, their definitions may be
+removed from ``drm_mipi_dsi.c``.
 
 Contact: Douglas Anderson <dianders@chromium.org>
 
-- 
2.50.1

Re: [PATCH v5 1/4] drm: Create mipi_dsi_dual* macros

[Dmitry Baryshkov]

On Sat, Jul 19, 2025 at 02:26:35AM -0600, Brigham Campbell wrote:
> Create mipi_dsi_dual, mipi_dsi_dual_dcs_write_seq_multi, and
> mipi_dsi_dual_generic_write_seq_multi macros for panels which are driven
> by two parallel serial interfaces. This allows for the reduction of code
> duplication in drivers for these panels.
> 
> Signed-off-by: Brigham Campbell <me@brighamcampbell.com>
> ---
> 
> mipi_dsi_dual_dcs_write_seq_multi goes unused by jdi-lpm102a188a. It's
> included in this patch for completeness and in anticipation of its use
> in other drivers in the future.
> 
>  drivers/gpu/drm/drm_mipi_dsi.c | 48 ++++++++++++++++++
>  include/drm/drm_mipi_dsi.h     | 89 ++++++++++++++++++++++++++++++++++
>  2 files changed, 137 insertions(+)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>


-- 
With best wishes
Dmitry

Re: [PATCH v5 1/4] drm: Create mipi_dsi_dual* macros

[Doug Anderson]

Hi,

On Sat, Jul 19, 2025 at 1:27 AM Brigham Campbell <me@brighamcampbell.com> wrote:
>
> @@ -827,6 +827,30 @@ void mipi_dsi_generic_write_multi(struct mipi_dsi_multi_context *ctx,
>  }
>  EXPORT_SYMBOL(mipi_dsi_generic_write_multi);
>
> +/**
> + * mipi_dsi_dual_generic_write_multi() - mipi_dsi_generic_write_multi() for
> + * two dsi channels, one after the other
> + * @dsi1: First dsi channel to write buffer to
> + * @dsi2: Second dsi channel to write buffer to
> + * @ctx: Context for multiple DSI transactions
> + * @payload: Buffer containing the payload
> + * @size: Size of payload buffer
> + *
> + * A wrapper around mipi_dsi_generic_write_multi() that allows the user to
> + * conveniently write to two dsi channels, one after the other.
> + */
> +void mpi_dsi_dual_generic_write_multi(struct mipi_dsi_device *dsi1,

BUG: above should be "mipi", not "mpi"


> +                                     struct mipi_dsi_device *dsi2,
> +                                     struct mipi_dsi_multi_context *ctx,
> +                                     const void *payload, size_t size)
> +{
> +       ctx->dsi = dsi1;
> +       mipi_dsi_generic_write_multi(ctx, data, len);

BUG: "data" and "len" are not valid local variables...


> @@ -431,6 +439,87 @@ void mipi_dsi_dcs_set_tear_off_multi(struct mipi_dsi_multi_context *ctx);
>                 mipi_dsi_dcs_write_buffer_multi(ctx, d, ARRAY_SIZE(d)); \
>         } while (0)
>
> +/**
> + * mipi_dsi_dual - send the same MIPI DSI command to two interfaces
> + *
> + * This macro will send the specified MIPI DSI command twice, once per each of
> + * the two interfaces supplied. This is useful for reducing duplication of code
> + * in panel drivers which use two parallel serial interfaces.
> + *
> + * WARNING: This macro reuses the _func argument and the optional trailing
> + * arguments twice each, which may cause unintended side effects. For example,
> + * adding the postfix increment ++ operator to one of the arguments to be
> + * passed to _func will cause the variable to be incremented twice instead of
> + * once and the variable will be its original value + 1 when sent to _dsi2.

It could be worth also pointing people to
mipi_dsi_dual_generic_write_seq_multi() and
mipi_dsi_dual_dcs_write_seq_multi() below?


> + *
> + * @_func: MIPI DSI function or macro to pass context and arguments into

nit: remove "or macro".


> + * @_dsi1: First DSI interface to act as recipient of the MIPI DSI command
> + * @_dsi2: Second DSI interface to act as recipient of the MIPI DSI command
> + * @_ctx: Context for multiple DSI transactions
> + * @...: Arguments to pass to MIPI DSI function or macro
> + */
> +#define mipi_dsi_dual(_func, _dsi1, _dsi2, _ctx, ...)           \
> +       do {                                                     \
> +               struct mipi_dsi_multi_context *_ctxcpy = (_ctx); \
> +               (_ctxcpy)->dsi = (_dsi1);                        \

nit: now that "_ctxcpy" is a local variable you no longer need the
extra parenthesis around it.


> +               (_func)((_ctxcpy), ##__VA_ARGS__);               \
> +               (_ctxcpy)->dsi = (_dsi2);                        \
> +               (_func)((_ctxcpy), ##__VA_ARGS__);               \
> +       } while (0)
> +
> +/**
> + * mipi_dsi_dual_generic_write_seq_multi - transmit data using a generic write
> + * packet to two dsi interfaces, one after the other
> + *
> + * This macro will send the specified generic packet twice, once per each of
> + * the two interfaces supplied. This is useful for reducing duplication of code
> + * in panel drivers which use two parallel serial interfaces.
> + *
> + * Note that if an error occurs while transmitting the packet to the first DSI
> + * interface, the packet will not be sent to the second DSI interface.
> + *
> + * This macro will print errors for you and error handling is optimized for
> + * callers that call this multiple times in a row.
> + *
> + * @_dsi1: First DSI interface to act as recipient of packet
> + * @_dsi2: Second DSI interface to act as recipient of packet
> + * @_ctx: Context for multiple DSI transactions
> + * @_seq: buffer containing the payload
> + */
> +#define mipi_dsi_dual_generic_write_seq_multi(_dsi1, _dsi2, _ctx, _seq...)     \
> +       do {                                                                    \
> +               static const u8 d[] = { _seq };                                 \
> +               mipi_dsi_dual_generic_write_multi(_dsi1, _dsi2, _ctx, d,        \
> +                                                        ARRAY_SIZE(d));        \

nit: the indentation of ARRAY_SIZE() is slightly off.


> +       } while (0)
> +
> +/**
> + * mipi_dsi_dual_dcs_write_seq_multi - transmit a DCS command with payload to
> + * two dsi interfaces, one after the other
> + *
> + * This macro will send the specified DCS command with payload twice, once per
> + * each of the two interfaces supplied. This is useful for reducing duplication
> + * of code in panel drivers which use two parallel serial interfaces.
> + *
> + * Note that if an error occurs while transmitting the payload to the first DSI
> + * interface, the payload will not be sent to the second DSI interface.
> + *
> + * This macro will print errors for you and error handling is optimized for
> + * callers that call this multiple times in a row.
> + *
> + * @_dsi1: First DSI interface to act as recipient of packet
> + * @_dsi2: Second DSI interface to act as recipient of packet
> + * @_ctx: Context for multiple DSI transactions
> + * @_cmd: Command
> + * @_seq: buffer containing the payload
> + */
> +#define mipi_dsi_dual_dcs_write_seq_multi(_dsi1, _dsi2, _ctx, _cmd, _seq)   \

BUG: doesn't "_seq" need to be "_seq..." ?

BUG: You need to remove the definition of this macro from
`panel-novatek-nt36523.c` or else it won't compile anymore since the
name of your macro is the exact same as theirs and they include this
header file. It would be OK w/ me if you squashed that into the same
patch since otherwise rejiggering things would just be churn...

I guess we also chose different argument orders than they did (that's
probably my fault, sorry!). They had the "ctx" still first and this
patch consistently has "dsi1" and "dsi2" first. I don't think it
really matters, but we should be consistent which means either
adjusting your patch or theirs. It's probably worth confirming that
the novatek driver at least compiles before you submit v6.


-Doug

Re: [PATCH v5 1/4] drm: Create mipi_dsi_dual* macros

[Brigham Campbell]

On Mon Jul 21, 2025 at 10:30 AM MDT, Doug Anderson wrote:
>> +void mpi_dsi_dual_generic_write_multi(struct mipi_dsi_device *dsi1,
>
> BUG: above should be "mipi", not "mpi"
>
>> +                                     struct mipi_dsi_device *dsi2,
>> +                                     struct mipi_dsi_multi_context *ctx,
>> +                                     const void *payload, size_t size)
>> +{
>> +       ctx->dsi = dsi1;
>> +       mipi_dsi_generic_write_multi(ctx, data, len);
>
> BUG: "data" and "len" are not valid local variables...
>
>> + * mipi_dsi_dual - send the same MIPI DSI command to two interfaces
>
> It could be worth also pointing people to
> mipi_dsi_dual_generic_write_seq_multi() and
> mipi_dsi_dual_dcs_write_seq_multi() below?
>
>> + * @_func: MIPI DSI function or macro to pass context and arguments into
>
> nit: remove "or macro".
>
>> +               struct mipi_dsi_multi_context *_ctxcpy = (_ctx); \
>> +               (_ctxcpy)->dsi = (_dsi1);                        \
>
> nit: now that "_ctxcpy" is a local variable you no longer need the
> extra parenthesis around it.
>
>> +               mipi_dsi_dual_generic_write_multi(_dsi1, _dsi2, _ctx, d,        \
>> +                                                        ARRAY_SIZE(d));        \
>
> nit: the indentation of ARRAY_SIZE() is slightly off.
>
>> +#define mipi_dsi_dual_dcs_write_seq_multi(_dsi1, _dsi2, _ctx, _cmd, _seq)   \
>
> BUG: doesn't "_seq" need to be "_seq..." ?
>
> BUG: You need to remove the definition of this macro from
> `panel-novatek-nt36523.c` or else it won't compile anymore since the
> name of your macro is the exact same as theirs and they include this
> header file. It would be OK w/ me if you squashed that into the same
> patch since otherwise rejiggering things would just be churn...

Sorry to have sent out such a poor quality patch, Doug! I always compile
changed files and test my changes when I can, but I think I must have
compiled just the lpm102a188a panel C source file itself by mistake when
I sent out this series revision. From now on, I'll simply enable the
relevant kernel config options and rebuild the entire kernel.

I'll address each of these items in v6.

> I guess we also chose different argument orders than they did (that's
> probably my fault, sorry!). They had the "ctx" still first and this
> patch consistently has "dsi1" and "dsi2" first. I don't think it
> really matters, but we should be consistent which means either
> adjusting your patch or theirs. It's probably worth confirming that
> the novatek driver at least compiles before you submit v6.

No, this was my fault. You had suggested the correct order. When I
implemented the change, I preferred to put `ctx` after `dsi1` and `dsi2`
because that's what I had done when I implemented the mipi_dsi_dual
macro. I'll swap up the order, remove the function definition from the
novatek driver, and compile both lpm102a188a and the novatek driver
before sending out v6.

By the way, we can discuss this further when I've sent out v6, but the
novatek driver appears to pass a mipi_dsi_context struct into the
write_seq_multi macro directly instead of a mipi_dsi_context struct
pointer. We opted to use a pointer in this patch series so that it can
be passed to a function in order to reduce the compiled size of drivers.
For now, I'll plan to solve this by changing calls to write_seq_multi in
the novatek driver to pass a pointer. I hope that the churn that this
will cause in the novatek driver isn't unacceptable.

Thanks for your patience,
Brigham

Re: [PATCH v5 1/4] drm: Create mipi_dsi_dual* macros

[Doug Anderson]

Hi,

On Mon, Jul 21, 2025 at 5:43 PM Brigham Campbell <me@brighamcampbell.com> wrote:
>
> On Mon Jul 21, 2025 at 10:30 AM MDT, Doug Anderson wrote:
> >> +void mpi_dsi_dual_generic_write_multi(struct mipi_dsi_device *dsi1,
> >
> > BUG: above should be "mipi", not "mpi"
> >
> >> +                                     struct mipi_dsi_device *dsi2,
> >> +                                     struct mipi_dsi_multi_context *ctx,
> >> +                                     const void *payload, size_t size)
> >> +{
> >> +       ctx->dsi = dsi1;
> >> +       mipi_dsi_generic_write_multi(ctx, data, len);
> >
> > BUG: "data" and "len" are not valid local variables...
> >
> >> + * mipi_dsi_dual - send the same MIPI DSI command to two interfaces
> >
> > It could be worth also pointing people to
> > mipi_dsi_dual_generic_write_seq_multi() and
> > mipi_dsi_dual_dcs_write_seq_multi() below?
> >
> >> + * @_func: MIPI DSI function or macro to pass context and arguments into
> >
> > nit: remove "or macro".
> >
> >> +               struct mipi_dsi_multi_context *_ctxcpy = (_ctx); \
> >> +               (_ctxcpy)->dsi = (_dsi1);                        \
> >
> > nit: now that "_ctxcpy" is a local variable you no longer need the
> > extra parenthesis around it.
> >
> >> +               mipi_dsi_dual_generic_write_multi(_dsi1, _dsi2, _ctx, d,        \
> >> +                                                        ARRAY_SIZE(d));        \
> >
> > nit: the indentation of ARRAY_SIZE() is slightly off.
> >
> >> +#define mipi_dsi_dual_dcs_write_seq_multi(_dsi1, _dsi2, _ctx, _cmd, _seq)   \
> >
> > BUG: doesn't "_seq" need to be "_seq..." ?
> >
> > BUG: You need to remove the definition of this macro from
> > `panel-novatek-nt36523.c` or else it won't compile anymore since the
> > name of your macro is the exact same as theirs and they include this
> > header file. It would be OK w/ me if you squashed that into the same
> > patch since otherwise rejiggering things would just be churn...
>
> Sorry to have sent out such a poor quality patch, Doug! I always compile
> changed files and test my changes when I can, but I think I must have
> compiled just the lpm102a188a panel C source file itself by mistake when
> I sent out this series revision. From now on, I'll simply enable the
> relevant kernel config options and rebuild the entire kernel.
>
> I'll address each of these items in v6.

Don't worry too much about it. While it's good to make sure you test
your patches, everyone makes mistakes! :-)


> > I guess we also chose different argument orders than they did (that's
> > probably my fault, sorry!). They had the "ctx" still first and this
> > patch consistently has "dsi1" and "dsi2" first. I don't think it
> > really matters, but we should be consistent which means either
> > adjusting your patch or theirs. It's probably worth confirming that
> > the novatek driver at least compiles before you submit v6.
>
> No, this was my fault. You had suggested the correct order. When I
> implemented the change, I preferred to put `ctx` after `dsi1` and `dsi2`
> because that's what I had done when I implemented the mipi_dsi_dual
> macro. I'll swap up the order, remove the function definition from the
> novatek driver, and compile both lpm102a188a and the novatek driver
> before sending out v6.
>
> By the way, we can discuss this further when I've sent out v6, but the
> novatek driver appears to pass a mipi_dsi_context struct into the
> write_seq_multi macro directly instead of a mipi_dsi_context struct
> pointer. We opted to use a pointer in this patch series so that it can
> be passed to a function in order to reduce the compiled size of drivers.
> For now, I'll plan to solve this by changing calls to write_seq_multi in
> the novatek driver to pass a pointer. I hope that the churn that this
> will cause in the novatek driver isn't unacceptable.

Looks fine. It probably should have been a pointer in the novatek
driver to begin with, but when it was a macro it didn't really matter.

-Doug