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From: "Noralf Trønnes" <noralf@tronnes.org>
To: robh+dt@kernel.org, david@lechnology.com
Cc: devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-fbdev@vger.kernel.org, linux-staging@lists.linux.dev,
	dave.stevenson@raspberrypi.com, maxime@cerno.tech,
	"Noralf Trønnes" <noralf@tronnes.org>
Subject: [PATCH 3/6] dt-bindings: display: sitronix,st7735r: Remove spi-max-frequency limit
Date: Wed, 24 Nov 2021 16:07:54 +0100	[thread overview]
Message-ID: <20211124150757.17929-4-noralf@tronnes.org> (raw)
In-Reply-To: <20211124150757.17929-1-noralf@tronnes.org>

The datasheet lists the minimum Serial clock cycle (Write) as 66ns which is
15MHz. Mostly it can do much better than that and is in fact often run at
32MHz. With a clever driver that runs configuration commands at a low speed
and only the pixel data at the maximum speed the configuration can't be
messed up by transfer errors and the speed is only limited by the amount of
pixel glitches that one is able to tolerate.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
---
 .../devicetree/bindings/display/sitronix,st7735r.yaml         | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/sitronix,st7735r.yaml b/Documentation/devicetree/bindings/display/sitronix,st7735r.yaml
index f81d0d0d51fe..157b1a7b18f9 100644
--- a/Documentation/devicetree/bindings/display/sitronix,st7735r.yaml
+++ b/Documentation/devicetree/bindings/display/sitronix,st7735r.yaml
@@ -32,15 +32,13 @@ properties:
               - okaya,rh128128t
           - const: sitronix,st7715r
 
-  spi-max-frequency:
-    maximum: 32000000
-
   dc-gpios:
     maxItems: 1
     description: Display data/command selection (D/CX)
 
   backlight: true
   reg: true
+  spi-max-frequency: true
   reset-gpios: true
   rotation: true
 
-- 
2.33.0


  parent reply	other threads:[~2021-11-24 15:17 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-24 15:07 [PATCH 0/6] drm/tiny/st7735r: Match up with staging/fbtft driver Noralf Trønnes
2021-11-24 15:07 ` [PATCH 1/6] dt-bindings: display: sitronix,st7735r: Fix backlight in example Noralf Trønnes
2021-12-01 21:57   ` Rob Herring
2021-12-06  8:53   ` Geert Uytterhoeven
2021-12-06 15:18   ` David Lechner
2021-11-24 15:07 ` [PATCH 2/6] dt-bindings: display: sitronix,st7735r: Make reset-gpios optional Noralf Trønnes
2021-12-01 21:57   ` Rob Herring
2021-12-06 15:18   ` David Lechner
2021-11-24 15:07 ` Noralf Trønnes [this message]
2021-12-01 21:57   ` [PATCH 3/6] dt-bindings: display: sitronix,st7735r: Remove spi-max-frequency limit Rob Herring
2021-12-06 15:19   ` David Lechner
2021-12-06 16:02     ` Noralf Trønnes
2021-11-24 15:07 ` [PATCH 4/6] dt-bindings: display: sitronix,st7735r: Add initialization properties Noralf Trønnes
2021-12-01 22:08   ` Rob Herring
2021-11-24 15:07 ` [PATCH 5/6] drm/mipi-dbi: Add device property functions Noralf Trønnes
2021-11-24 15:07 ` [PATCH 6/6] drm: tiny: st7735r: Support DT initialization of controller Noralf Trønnes
2021-11-24 22:03 ` [PATCH 0/6] drm/tiny/st7735r: Match up with staging/fbtft driver David Lechner
2021-11-25 17:21   ` Noralf Trønnes
2021-11-29  9:39   ` Maxime Ripard
2021-11-30  8:13     ` Geert Uytterhoeven
2021-11-30  9:03       ` Maxime Ripard
2021-11-30 14:30     ` Noralf Trønnes
2021-12-01 14:52       ` Maxime Ripard
2021-12-06 15:26         ` David Lechner
2021-12-06 16:04           ` Noralf Trønnes
2022-03-09 10:37 ` Noralf Trønnes

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