Re: [PATCH v4 3/3] ARM: dts: sun7i: Add support for the Ainol AW1 tablet

Maxime Ripard
2018-05-11T14:36:47Z

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On Tue, May 08, 2018 at 12:04:13AM +0200, Paul Kocialkowski wrote:
> +++ b/arch/arm/boot/dts/sun7i-a20-ainol-aw1.dts
> @@ -0,0 +1,297 @@
> +/*
> + * SPDX-License-Identifier: (GPL-2.0+ OR MIT)

This really should be the first line, and with a C++ style comment, as
in:

// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
/*
* Copyright (C) ...

See Documentation/process/license-rules.rst

> + backlight: backlight {
> + compatible = "pwm-backlight";
> + pwms = <&pwm 0 50000 PWM_POLARITY_INVERTED>;
> + brightness-levels = < 0 1 1 1 1 2 2 2
> + 2 3 3 3 3 4 4 4
> + 5 5 5 6 6 6 7 7
> + 8 8 8 9 9 9 10 10
> + 10 11 11 12 12 12 13 13
> + 14 14 14 15 15 16 16 17
> + 17 17 18 18 19 19 20 20
> + 21 21 21 22 22 23 23 24
> + 24 25 25 26 26 27 27 28
> + 28 29 30 30 31 31 32 32
> + 33 33 34 35 35 36 36 37
> + 38 38 39 39 40 41 41 42
> + 43 43 44 44 45 46 47 47
> + 48 49 49 50 51 51 52 53
> + 54 54 55 56 57 57 58 59
> + 60 61 61 62 63 64 65 65
> + 66 67 68 69 70 71 71 72
> + 73 74 75 76 77 78 79 80
> + 81 82 83 84 85 86 87 88
> + 89 90 91 92 93 94 95 96
> + 97 98 99 101 102 103 104 105
> + 106 108 109 110 111 112 114 115
> + 116 117 119 120 121 123 124 125
> + 127 128 129 131 132 133 135 136
> + 138 139 141 142 144 145 147 148
> + 150 151 153 154 156 157 159 161
> + 162 164 166 167 169 171 173 174
> + 176 178 180 181 183 185 187 189
> + 191 192 194 196 198 200 202 204
> + 206 208 210 212 214 216 219 221
> + 223 225 227 229 232 234 236 238
> + 241 242 244 246 248 250 253 255>;

You kind of overdid it here :)

What I meant to say before was that if you have 10 elements (and you
really should have something in that magnitude) each step should
increase the perceived brightness by 10%.

In this particular case, I really think having something close to <0 4
8 16 32 64 128 255> would be enough.

And in general, that kind of odd looking table without any more
context is just screaming for a comment :)

Maxime

--
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering