[PATCH v2] drm/panel: novatek-nt36672a: Convert to mipi_dsi_*_multi() helpers

[PATCH v2] drm/panel: novatek-nt36672a: Convert to mipi_dsi_*_multi() helpers

[Chintan Patel]

Convert the driver to use the non-deprecated mipi_dsi_*_multi() helpers and
mipi_dsi_msleep().

Switch DCS command sequences to the multi context API and
accumulate errors via struct mipi_dsi_multi_context. Replace
open-coded error handling with the multi helpers and convert
nt36672a_send_cmds() and power sequencing accordingly.

Signed-off-by: Chintan Patel <chintanlike@gmail.com>
---
Changes in v2:
- Address alignment feedback from Doug.
- Restore original power-down ordering.
- Drop return value from nt36672a_panel_power_off().
- Consolidate error handling around dsi_ctx.accum_err.

 .../gpu/drm/panel/panel-novatek-nt36672a.c    | 98 ++++++-------------
 1 file changed, 30 insertions(+), 68 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-novatek-nt36672a.c b/drivers/gpu/drm/panel/panel-novatek-nt36672a.c
index 29e1f6aea480..3ebdc3048b26 100644
--- a/drivers/gpu/drm/panel/panel-novatek-nt36672a.c
+++ b/drivers/gpu/drm/panel/panel-novatek-nt36672a.c
@@ -79,70 +79,53 @@ static inline struct nt36672a_panel *to_nt36672a_panel(struct drm_panel *panel)
 	return container_of(panel, struct nt36672a_panel, base);
 }
 
-static int nt36672a_send_cmds(struct drm_panel *panel, const struct nt36672a_panel_cmd *cmds,
-			      int num)
+static void nt36672a_send_cmds(struct mipi_dsi_multi_context *dsi_ctx,
+			       const struct nt36672a_panel_cmd *cmds, int num)
 {
-	struct nt36672a_panel *pinfo = to_nt36672a_panel(panel);
 	unsigned int i;
-	int err;
 
 	for (i = 0; i < num; i++) {
 		const struct nt36672a_panel_cmd *cmd = &cmds[i];
 
-		err = mipi_dsi_dcs_write(pinfo->link, cmd->data[0], cmd->data + 1, 1);
-
-		if (err < 0)
-			return err;
+		/* cmd->data[0] is the DCS command, cmd->data[1] is the parameter */
+		mipi_dsi_dcs_write_buffer_multi(dsi_ctx, cmd->data, sizeof(cmd->data));
 	}
-
-	return 0;
 }
 
-static int nt36672a_panel_power_off(struct drm_panel *panel)
+static void nt36672a_panel_power_off(struct drm_panel *panel)
 {
 	struct nt36672a_panel *pinfo = to_nt36672a_panel(panel);
-	int ret = 0;
 
 	gpiod_set_value(pinfo->reset_gpio, 1);
 
-	ret = regulator_bulk_disable(ARRAY_SIZE(pinfo->supplies), pinfo->supplies);
-	if (ret)
-		dev_err(panel->dev, "regulator_bulk_disable failed %d\n", ret);
-
-	return ret;
+	if (regulator_bulk_disable(ARRAY_SIZE(pinfo->supplies), pinfo->supplies) < 0)
+		dev_err(panel->dev, "regulator_bulk_disable failed\n");
 }
 
 static int nt36672a_panel_unprepare(struct drm_panel *panel)
 {
 	struct nt36672a_panel *pinfo = to_nt36672a_panel(panel);
-	int ret;
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = pinfo->link };
 
 	/* send off cmds */
-	ret = nt36672a_send_cmds(panel, pinfo->desc->off_cmds,
-				 pinfo->desc->num_off_cmds);
+	nt36672a_send_cmds(&dsi_ctx, pinfo->desc->off_cmds,
+			   pinfo->desc->num_off_cmds);
 
-	if (ret < 0)
-		dev_err(panel->dev, "failed to send DCS off cmds: %d\n", ret);
-
-	ret = mipi_dsi_dcs_set_display_off(pinfo->link);
-	if (ret < 0)
-		dev_err(panel->dev, "set_display_off cmd failed ret = %d\n", ret);
+	mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
+	/* Reset error to continue power-down even if display off failed */
+	dsi_ctx.accum_err = 0;
 
 	/* 120ms delay required here as per DCS spec */
 	msleep(120);
 
-	ret = mipi_dsi_dcs_enter_sleep_mode(pinfo->link);
-	if (ret < 0)
-		dev_err(panel->dev, "enter_sleep cmd failed ret = %d\n", ret);
+	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx);
 
 	/* 0x3C = 60ms delay */
-	msleep(60);
+	mipi_dsi_msleep(&dsi_ctx, 60);
 
-	ret = nt36672a_panel_power_off(panel);
-	if (ret < 0)
-		dev_err(panel->dev, "power_off failed ret = %d\n", ret);
+	nt36672a_panel_power_off(panel);
 
-	return ret;
+	return 0;
 }
 
 static int nt36672a_panel_power_on(struct nt36672a_panel *pinfo)
@@ -170,52 +153,31 @@ static int nt36672a_panel_power_on(struct nt36672a_panel *pinfo)
 static int nt36672a_panel_prepare(struct drm_panel *panel)
 {
 	struct nt36672a_panel *pinfo = to_nt36672a_panel(panel);
-	int err;
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = pinfo->link };
 
-	err = nt36672a_panel_power_on(pinfo);
-	if (err < 0)
-		goto poweroff;
+	dsi_ctx.accum_err = nt36672a_panel_power_on(pinfo);
 
 	/* send first part of init cmds */
-	err = nt36672a_send_cmds(panel, pinfo->desc->on_cmds_1,
-				 pinfo->desc->num_on_cmds_1);
+	nt36672a_send_cmds(&dsi_ctx, pinfo->desc->on_cmds_1,
+			   pinfo->desc->num_on_cmds_1);
 
-	if (err < 0) {
-		dev_err(panel->dev, "failed to send DCS Init 1st Code: %d\n", err);
-		goto poweroff;
-	}
-
-	err = mipi_dsi_dcs_exit_sleep_mode(pinfo->link);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
-		goto poweroff;
-	}
+	mipi_dsi_dcs_exit_sleep_mode_multi(&dsi_ctx);
 
 	/* 0x46 = 70 ms delay */
-	msleep(70);
+	mipi_dsi_msleep(&dsi_ctx, 70);
 
-	err = mipi_dsi_dcs_set_display_on(pinfo->link);
-	if (err < 0) {
-		dev_err(panel->dev, "failed to Set Display ON: %d\n", err);
-		goto poweroff;
-	}
+	mipi_dsi_dcs_set_display_on_multi(&dsi_ctx);
 
 	/* Send rest of the init cmds */
-	err = nt36672a_send_cmds(panel, pinfo->desc->on_cmds_2,
-				 pinfo->desc->num_on_cmds_2);
+	nt36672a_send_cmds(&dsi_ctx, pinfo->desc->on_cmds_2,
+			   pinfo->desc->num_on_cmds_2);
 
-	if (err < 0) {
-		dev_err(panel->dev, "failed to send DCS Init 2nd Code: %d\n", err);
-		goto poweroff;
-	}
+	mipi_dsi_msleep(&dsi_ctx, 120);
 
-	msleep(120);
+	if (dsi_ctx.accum_err < 0)
+		gpiod_set_value(pinfo->reset_gpio, 0);
 
-	return 0;
-
-poweroff:
-	gpiod_set_value(pinfo->reset_gpio, 0);
-	return err;
+	return dsi_ctx.accum_err;
 }
 
 static int nt36672a_panel_get_modes(struct drm_panel *panel,
-- 
2.43.0

Claude review: drm/panel: novatek-nt36672a: Convert to mipi_dsi_*_multi() helpers

[Claude Code Review Bot]

Overall Series Review

Subject: drm/panel: novatek-nt36672a: Convert to mipi_dsi_*_multi() helpers
Author: Chintan Patel <chintanlike@gmail.com>
Patches: 1
Reviewed: 2026-03-04T07:58:46.804279

---

This is a single-patch conversion of the `panel-novatek-nt36672a` driver from the deprecated `mipi_dsi_dcs_*()` API to the `mipi_dsi_*_multi()` helpers with `struct mipi_dsi_multi_context`. The conversion is largely correct and well-structured for a v2 submission. However, there is one behavioral change in the unprepare error path that silently drops a DSI command when an earlier step fails, which changes the original "always try everything during power-down" behavior.

---
Generated by Claude Code Patch Reviewer

Claude review: drm/panel: novatek-nt36672a: Convert to mipi_dsi_*_multi() helpers

[Claude Code Review Bot]

Patch Review

**nt36672a_send_cmds conversion** - The switch from `mipi_dsi_dcs_write(pinfo->link, cmd->data[0], cmd->data + 1, 1)` to `mipi_dsi_dcs_write_buffer_multi(dsi_ctx, cmd->data, sizeof(cmd->data))` is semantically equivalent. Good.

**Behavioral change in unprepare error path** - This is the main concern. In the new code at lines 111-116:

```c
nt36672a_send_cmds(&dsi_ctx, pinfo->desc->off_cmds,
		   pinfo->desc->num_off_cmds);

mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
/* Reset error to continue power-down even if display off failed */
dsi_ctx.accum_err = 0;
```

If `nt36672a_send_cmds()` fails (setting `accum_err`), then `mipi_dsi_dcs_set_display_off_multi()` will be a no-op because all `_multi` helpers bail out early when `accum_err != 0`. The `accum_err = 0` reset comes *after* `set_display_off_multi`, so it doesn't help. In the original code, `set_display_off` was always attempted independently regardless of whether off_cmds succeeded. For a power-down path, you generally want to try everything. The reset should be moved *before* `set_display_off_multi`:

```c
nt36672a_send_cmds(&dsi_ctx, pinfo->desc->off_cmds,
		   pinfo->desc->num_off_cmds);

/* Reset error to continue power-down even if off cmds failed */
dsi_ctx.accum_err = 0;

mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
```

Or alternatively, reset `accum_err` both before `set_display_off_multi` and after it, to also handle its failure.

**120ms sleep uses plain `msleep()` instead of `mipi_dsi_msleep()`** (line 119) - This is actually correct behavior here, since the 120ms delay must always occur unconditionally during power-down regardless of prior errors. Good.

**nt36672a_panel_prepare error path** - The pattern of seeding `accum_err` from `nt36672a_panel_power_on()` at line 158 is a good use of the multi context:

```c
dsi_ctx.accum_err = nt36672a_panel_power_on(pinfo);
```

The error cleanup at lines 177-178 preserves the original behavior:

```c
if (dsi_ctx.accum_err < 0)
    gpiod_set_value(pinfo->reset_gpio, 0);
```

Note: the original `poweroff:` label also set the GPIO to 0, which appears to be a pre-existing issue (this de-asserts reset rather than re-asserting it, so it's effectively a no-op after a successful `power_on`). Not introduced by this patch.

**Lost error context** - The original code had specific `dev_err` messages like `"failed to send DCS off cmds: %d"` and `"set_display_off cmd failed ret = %d"`. These are all removed. While the low-level `_multi` helpers do log transport-level errors, the higher-level context (which operation was being attempted) is lost. This is typical for multi conversions and generally accepted, but worth noting.

**nt36672a_panel_power_off** - Dropping the error code from the log message (line 101-102):

```c
if (regulator_bulk_disable(ARRAY_SIZE(pinfo->supplies), pinfo->supplies) < 0)
    dev_err(panel->dev, "regulator_bulk_disable failed\n");
```

Minor nit: the original included `%d` with the error code, which can be useful for debugging. Consider preserving it:
```c
int ret = regulator_bulk_disable(...);
if (ret)
    dev_err(panel->dev, "regulator_bulk_disable failed %d\n", ret);
```

**Summary**: The conversion is mostly correct. The one issue that should be fixed before merging is the `accum_err` reset placement in `nt36672a_panel_unprepare()`, which causes `set_display_off` to be skipped when `send_cmds` fails. Move the reset before `set_display_off_multi()` to preserve the original always-try-everything power-down behavior.

---
Generated by Claude Code Patch Reviewer