[PATCH] ARM: dts: imx53: add support for Ka-Ro TX53 modules

On Fri, Dec 13, 2013 at 10:54:17AM +0100, Lothar Wa?mann wrote:

quoted

quoted

+		compatible = "pwm-backlight";
+		pwms = <&pwm2 0 500000>;
+		power-supply = <&reg_3v3>;
+		brightness-levels = <
+			100 99 98 97 96 95 94 93 92 91
+			 90 89 88 87 86 85 84 83 82 81
+			 80 79 78 77 76 75 74 73 72 71
+			 70 69 68 67 66 65 64 63 62 61
+			 60 59 58 57 56 55 54 53 52 51
+			 50 49 48 47 46 45 44 43 42 41
+			 40 39 38 37 36 35 34 33 32 31
+			 30 29 28 27 26 25 24 23 22 21
+			 20 19 18 17 16 15 14 13 12 11
+			 10  9  8  7  6  5  4  3  2  1
+			  0

Why is it so unique to start with 100 and end with 0?  Does it even
work?  Here is what I read from bindings doc.

Yes, it works. The backlight control of the displays we typically use
is active low. This is a poor man's way to get an inverted PWM output!
(And one in which the number written to the sysfs file corresponds to
the actual duty cycle of the PWM output)

I think Linux pwm driver should be improved for this case rather than
manipulate device tree in a way that violate the defined bindings.

Shawn