BCM270X_DT: mz61581: Set txbuflen to 32k

Because of the spi dma mapping/engine overhead with spi-bcm2835, txbuflen has to be increased from 4096 to 32768 to maximize throughput (11MB/s at 128MHz). Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
raspberrypi · Sep 14, 2015 · 5893b0b · 5893b0b
1 parent 2a8c002
commit 5893b0b
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diff --git a/arch/arm/boot/dts/overlays/README b/arch/arm/boot/dts/overlays/README
@@ -368,6 +368,8 @@ Params: speed                    Display SPI bus speed
 
         fps                      Delay between frame updates
 
+        txbuflen                 Transmit buffer length (default 32768)
+
         debug                    Debug output level {0-7}
 
         xohms                    Touchpanel sensitivity (X-plate resistance)

diff --git a/arch/arm/boot/dts/overlays/mz61581-overlay.dts b/arch/arm/boot/dts/overlays/mz61581-overlay.dts
@@ -57,6 +57,7 @@
 				bgr;
 				fps = <30>;
 				buswidth = <8>;
+				txbuflen = <32768>;
 
 				reset-gpios = <&gpio 15 0>;
 				dc-gpios = <&gpio 25 0>;
@@ -103,6 +104,7 @@
 		speed =   <&mz61581>, "spi-max-frequency:0";
 		rotate =  <&mz61581>, "rotate:0";
 		fps =     <&mz61581>, "fps:0";
+		txbuflen = <&mz61581>, "txbuflen:0";
 		debug =   <&mz61581>, "debug:0";
 		xohms =   <&mz61581_ts>,"ti,x-plate-ohms;0";
 	};