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

Hi,

On Mon, Mar 2, 2026 at 7:55 PM Chintan Patel <chintanlike@gmail.com> wrote:
>
> -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");

nit: IMO It would have been OK to keep the local "ret" variable here,
but I won't insist. That would have allowed you to keep printing the
error code, which is nice. It's OK to have "ret" as a local variable
even if you aren't returning it...


>  }
>
>  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);

Probably also need a `dsi_ctx.accum_err = 0;` here? Old code still
sent the "display off" command even if nt36672a_send_cmds() returned
an error I think?


> +       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);

I think this one should still be a regular msleep(60), right? Prior
code still did msleep(60) even if mipi_dsi_dcs_enter_sleep_mode()
returned an error, so you probably still should too.


> -       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;

I didn't notice before, but I guess this is a minor change. Previously
nt36672a_panel_unprepare() would ignore all errors (other than
printing) except it would return the final error return from the
regulator_bulk_disable() call. Now it will also ignore the error from
the regulator_bulk_disable().

IMO this is fine, but since it's a slight change in functionality it
could be noted in the commit message. Something like:

This patch is intended to functionally be a no-op, though there is one
slight change. Previously a failure in regulator_bulk_disable() would
have caused nt36672a_panel_unprepare() to return an error. Now it
won't. No other errors in nt36672a_panel_unprepare() were propagated,
so this makes things consistent.

Hi Doug,

Thanks for the detailed review — this is very helpful.

Good catch on a few of these.

> 
> On Mon, Mar 2, 2026 at 7:55 PM Chintan Patel <chintanlike@gmail.com> wrote:
>>
>> -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");
> 
> nit: IMO It would have been OK to keep the local "ret" variable here,
> but I won't insist. That would have allowed you to keep printing the
> error code, which is nice. It's OK to have "ret" as a local variable
> even if you aren't returning it...
> 

I’ll restore the local ret variable in nt36672a_panel_power_off() so we 
continue printing the regulator error code even though the function now 
returns void.


>>   }
>>
>>   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);
> 
> Probably also need a `dsi_ctx.accum_err = 0;` here? Old code still
> sent the "display off" command even if nt36672a_send_cmds() returned
> an error I think?
> 

You’re right about needing to reset dsi_ctx.accum_err before calling 
mipi_dsi_dcs_set_display_off_multi(). The old code would still send the 
display-off command even if nt36672a_send_cmds() failed, so I’ll add the 
reset there to preserve the original behavior.

>> +       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);
> 
> I think this one should still be a regular msleep(60), right? Prior
> code still did msleep(60) even if mipi_dsi_dcs_enter_sleep_mode()
> returned an error, so you probably still should too.
> 

Agreed on keeping the msleep(60) as a regular sleep. Since the old code 
always slept regardless of DSI errors, using mipi_dsi_msleep() there 
would subtly change the power-down timing semantics.
>> -       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;
> 
> I didn't notice before, but I guess this is a minor change. Previously
> nt36672a_panel_unprepare() would ignore all errors (other than
> printing) except it would return the final error return from the
> regulator_bulk_disable() call. Now it will also ignore the error from
> the regulator_bulk_disable().
> 
> IMO this is fine, but since it's a slight change in functionality it
> could be noted in the commit message. Something like:
> 
> This patch is intended to functionally be a no-op, though there is one
> slight change. Previously a failure in regulator_bulk_disable() would
> have caused nt36672a_panel_unprepare() to return an error. Now it
> won't. No other errors in nt36672a_panel_unprepare() were propagated,
> so this makes things consistent.


I’ll also note in the commit message that nt36672a_panel_unprepare() no 
longer propagates the regulator error, since previously that was the 
only error returned and all others were ignored.

I’ll send a v3 shortly incorporating these adjustments.

Thanks again for the careful review.

-Chintan