On 8/13/25 9:34 AM, Tomi Valkeinen wrote:
Hi,
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 b3e57217ae63..cefa7e92b5b8 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
@@ -80,10 +80,7 @@
* 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 BIT(8)
Looks fine, but do you know what the TXSETR register does? It also has
LANECNT, but I don't see the driver touching that register at all.
TXSETR:LANECNT default value is 3 (4 lanes), which matches with the old
hardcoded behavior for PPISETR... So I wonder if that register should
also be set?
Ah, never mind, I now saw the patch 3 =). But should it be before patch
2? Hmm, I guess that ordering is no better. Should they be combined into
"support 1,2,3 datalanes" patch?
I think each patch fixes slighly different issue, even if the issues are
related. I tried to keep the issue description in each patch commit
message for posterity. I can squash them if you think that's better, I
don't mind either way.
I was thinking about this the user's or backporting point of view.
Neither of the commits (clearly) say that they add support for 1/2/3
lane modes.
The 1/2/3 lane mode was already implemented in the driver, except it was
broken.
You say they "fix", but they're not quite fixes either. The
patch 3 could be considered a fix, but at the moment it just writes the
default value to the register, so no point in marking it as a fix to be
backported.
3/4 does write the DSI lane count into TXSETR , not the default value.
So... I don't have a strong opinion, but I think a single patch that
adds support to 1, 2,3 lanes makes most sense.
Lemme send a single patch with Fixes tag then. The combined patch does
not look too great though.
