[PATCH v2] drm/rcar-du: dsi: Fix 1/2/3 lane support

[PATCH v2] drm/rcar-du: dsi: Fix 1/2/3 lane support

[Marek Vasut]

Remove fixed PPI lane count setup. The R-Car DSI host is capable
of operating in 1..4 DSI lane mode. Remove the hard-coded 4-lane
configuration from PPI register settings and instead configure
the PPI lane count according to lane count information already
obtained by this driver instance.

Configure TXSETR register to match PPI lane count. The R-Car V4H
Reference Manual R19UH0186EJ0121 Rev.1.21 section 67.2.2.3 Tx Set
Register (TXSETR), field LANECNT description indicates that the
TXSETR register LANECNT bitfield lane count must be configured
such, that it matches lane count configuration in PPISETR register
DLEN bitfield. Make sure the LANECNT and DLEN bitfields are
configured to match.

Fixes: 155358310f01 ("drm: rcar-du: Add R-Car DSI driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: David Airlie <airlied@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-renesas-soc@vger.kernel.org
---
V2: - Split this out of a series, update commit message, combine from
      drm/rcar-du: dsi: Remove fixed PPI lane count setup
      drm/rcar-du: dsi: Configure TXSETR register to match PPI lane count
    - add Fixes tag, CC stable
---
 drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c      | 5 ++++-
 drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h | 8 ++++----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
index 1af4c73f7a88..952c3efb74da 100644
--- a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
@@ -576,7 +576,10 @@ static int rcar_mipi_dsi_startup(struct rcar_mipi_dsi *dsi,
 	udelay(10);
 	rcar_mipi_dsi_clr(dsi, CLOCKSET1, CLOCKSET1_UPDATEPLL);
 
-	ppisetr = PPISETR_DLEN_3 | PPISETR_CLEN;
+	rcar_mipi_dsi_clr(dsi, TXSETR, TXSETR_LANECNT_MASK);
+	rcar_mipi_dsi_set(dsi, TXSETR, dsi->lanes - 1);
+
+	ppisetr = ((BIT(dsi->lanes) - 1) & PPISETR_DLEN_MASK) | PPISETR_CLEN;
 	rcar_mipi_dsi_write(dsi, PPISETR, ppisetr);
 
 	rcar_mipi_dsi_set(dsi, PHYSETUP, PHYSETUP_SHUTDOWNZ);
diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h
index a6b276f1d6ee..a54c7eb4113b 100644
--- a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h
@@ -12,6 +12,9 @@
 #define LINKSR_LPBUSY			(1 << 1)
 #define LINKSR_HSBUSY			(1 << 0)
 
+#define TXSETR				0x100
+#define TXSETR_LANECNT_MASK		(0x3 << 0)
+
 /*
  * Video Mode Register
  */
@@ -80,10 +83,7 @@
  * PHY-Protocol Interface (PPI) Registers
  */
 #define PPISETR				0x700
-#define PPISETR_DLEN_0			(0x1 << 0)
-#define PPISETR_DLEN_1			(0x3 << 0)
-#define PPISETR_DLEN_2			(0x7 << 0)
-#define PPISETR_DLEN_3			(0xf << 0)
+#define PPISETR_DLEN_MASK		(0xf << 0)
 #define PPISETR_CLEN			(1 << 8)
 
 #define PPICLCR				0x710
-- 
2.47.2

Re: [PATCH v2] drm/rcar-du: dsi: Fix 1/2/3 lane support

[Tomi Valkeinen]

Hi,

On 14/08/2025 00:08, Marek Vasut wrote:
> Remove fixed PPI lane count setup. The R-Car DSI host is capable
> of operating in 1..4 DSI lane mode. Remove the hard-coded 4-lane
> configuration from PPI register settings and instead configure
> the PPI lane count according to lane count information already
> obtained by this driver instance.
> 
> Configure TXSETR register to match PPI lane count. The R-Car V4H
> Reference Manual R19UH0186EJ0121 Rev.1.21 section 67.2.2.3 Tx Set
> Register (TXSETR), field LANECNT description indicates that the
> TXSETR register LANECNT bitfield lane count must be configured
> such, that it matches lane count configuration in PPISETR register
> DLEN bitfield. Make sure the LANECNT and DLEN bitfields are
> configured to match.
> 
> Fixes: 155358310f01 ("drm: rcar-du: Add R-Car DSI driver")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> ---
> Cc: David Airlie <airlied@gmail.com>
> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Magnus Damm <magnus.damm@gmail.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Simona Vetter <simona@ffwll.ch>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-renesas-soc@vger.kernel.org
> ---
> V2: - Split this out of a series, update commit message, combine from
>       drm/rcar-du: dsi: Remove fixed PPI lane count setup
>       drm/rcar-du: dsi: Configure TXSETR register to match PPI lane count
>     - add Fixes tag, CC stable
> ---
>  drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c      | 5 ++++-
>  drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h | 8 ++++----
>  2 files changed, 8 insertions(+), 5 deletions(-)

Reviewed-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>

 Tomi

Re: [PATCH v2] drm/rcar-du: dsi: Fix 1/2/3 lane support

[Marek Vasut]

On 8/14/25 7:54 AM, Tomi Valkeinen wrote:

Hello Tomi,

> On 14/08/2025 00:08, Marek Vasut wrote:
>> Remove fixed PPI lane count setup. The R-Car DSI host is capable
>> of operating in 1..4 DSI lane mode. Remove the hard-coded 4-lane
>> configuration from PPI register settings and instead configure
>> the PPI lane count according to lane count information already
>> obtained by this driver instance.
>>
>> Configure TXSETR register to match PPI lane count. The R-Car V4H
>> Reference Manual R19UH0186EJ0121 Rev.1.21 section 67.2.2.3 Tx Set
>> Register (TXSETR), field LANECNT description indicates that the
>> TXSETR register LANECNT bitfield lane count must be configured
>> such, that it matches lane count configuration in PPISETR register
>> DLEN bitfield. Make sure the LANECNT and DLEN bitfields are
>> configured to match.
>>
>> Fixes: 155358310f01 ("drm: rcar-du: Add R-Car DSI driver")
>> Cc: <stable@vger.kernel.org>
>> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
>> ---
>> Cc: David Airlie <airlied@gmail.com>
>> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
>> Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
>> Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
>> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>> Cc: Magnus Damm <magnus.damm@gmail.com>
>> Cc: Maxime Ripard <mripard@kernel.org>
>> Cc: Simona Vetter <simona@ffwll.ch>
>> Cc: Thomas Zimmermann <tzimmermann@suse.de>
>> Cc: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
>> Cc: dri-devel@lists.freedesktop.org
>> Cc: linux-renesas-soc@vger.kernel.org
>> ---
>> V2: - Split this out of a series, update commit message, combine from
>>        drm/rcar-du: dsi: Remove fixed PPI lane count setup
>>        drm/rcar-du: dsi: Configure TXSETR register to match PPI lane count
>>      - add Fixes tag, CC stable
>> ---
>>   drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c      | 5 ++++-
>>   drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h | 8 ++++----
>>   2 files changed, 8 insertions(+), 5 deletions(-)
> 
> Reviewed-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Would you like to pick this up via drm-misc , or shall I ?

Re: [PATCH v2] drm/rcar-du: dsi: Fix 1/2/3 lane support

[Tomi Valkeinen]

Hi,

On 31/08/2025 20:01, Marek Vasut wrote:
> On 8/14/25 7:54 AM, Tomi Valkeinen wrote:
> 
> Hello Tomi,
> 
>> On 14/08/2025 00:08, Marek Vasut wrote:
>>> Remove fixed PPI lane count setup. The R-Car DSI host is capable
>>> of operating in 1..4 DSI lane mode. Remove the hard-coded 4-lane
>>> configuration from PPI register settings and instead configure
>>> the PPI lane count according to lane count information already
>>> obtained by this driver instance.
>>>
>>> Configure TXSETR register to match PPI lane count. The R-Car V4H
>>> Reference Manual R19UH0186EJ0121 Rev.1.21 section 67.2.2.3 Tx Set
>>> Register (TXSETR), field LANECNT description indicates that the
>>> TXSETR register LANECNT bitfield lane count must be configured
>>> such, that it matches lane count configuration in PPISETR register
>>> DLEN bitfield. Make sure the LANECNT and DLEN bitfields are
>>> configured to match.
>>>
>>> Fixes: 155358310f01 ("drm: rcar-du: Add R-Car DSI driver")
>>> Cc: <stable@vger.kernel.org>
>>> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
>>> ---
>>> Cc: David Airlie <airlied@gmail.com>
>>> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
>>> Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
>>> Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
>>> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>>> Cc: Magnus Damm <magnus.damm@gmail.com>
>>> Cc: Maxime Ripard <mripard@kernel.org>
>>> Cc: Simona Vetter <simona@ffwll.ch>
>>> Cc: Thomas Zimmermann <tzimmermann@suse.de>
>>> Cc: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
>>> Cc: dri-devel@lists.freedesktop.org
>>> Cc: linux-renesas-soc@vger.kernel.org
>>> ---
>>> V2: - Split this out of a series, update commit message, combine from
>>>        drm/rcar-du: dsi: Remove fixed PPI lane count setup
>>>        drm/rcar-du: dsi: Configure TXSETR register to match PPI lane
>>> count
>>>      - add Fixes tag, CC stable
>>> ---
>>>   drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c      | 5 ++++-
>>>   drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h | 8 ++++----
>>>   2 files changed, 8 insertions(+), 5 deletions(-)
>>
>> Reviewed-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
> Would you like to pick this up via drm-misc , or shall I ?

I'll push to drm-misc. Thanks!

 Tomi

Re: [PATCH v2] drm/rcar-du: dsi: Fix 1/2/3 lane support

[Marek Vasut]

On 9/1/25 11:22 AM, Tomi Valkeinen wrote:

Hello Tomi,

>> Would you like to pick this up via drm-misc , or shall I ?
> 
> I'll push to drm-misc. Thanks!

Thank you

-- 
Best regards,
Marek Vasut