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Subject[PATCH v2] ARM: dts: rockchip: Use interpolated brightness tables for veyron
Date
Use interpolated brightness tables (added by commit 573fe6d1c25
("backlight: pwm_bl: Linear interpolation between
brightness-levels") for veyron, instead of specifying every single
step. Some devices/panels have intervals that are smaller than
the specified 'num-interpolated-steps', the driver interprets
these intervals as a single step.

Another option would be to switch to a perceptual brightness curve
(CIE 1931), with the caveat that it would change the behavior of
the backlight. Also the concept of a minimum brightness level is
currently not supported for CIE 1931 curves.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---

Changes in v2:
- added 0 as first step for devices/panels that require a minimum
PWM duty cycle
- increased 'num-interpolated-steps' values by one, it's not the
number of steps between levels, but that number +1

arch/arm/boot/dts/rk3288-veyron-edp.dtsi | 35 ++--------------------
arch/arm/boot/dts/rk3288-veyron-jaq.dts | 35 ++--------------------
arch/arm/boot/dts/rk3288-veyron-minnie.dts | 35 ++--------------------
arch/arm/boot/dts/rk3288-veyron-tiger.dts | 35 ++--------------------
4 files changed, 8 insertions(+), 132 deletions(-)

diff --git a/arch/arm/boot/dts/rk3288-veyron-edp.dtsi b/arch/arm/boot/dts/rk3288-veyron-edp.dtsi
index b12e061c5f7f..300a7e32c978 100644
--- a/arch/arm/boot/dts/rk3288-veyron-edp.dtsi
+++ b/arch/arm/boot/dts/rk3288-veyron-edp.dtsi
@@ -41,39 +41,8 @@

backlight: backlight {
compatible = "pwm-backlight";
- brightness-levels = <
- 0 1 2 3 4 5 6 7
- 8 9 10 11 12 13 14 15
- 16 17 18 19 20 21 22 23
- 24 25 26 27 28 29 30 31
- 32 33 34 35 36 37 38 39
- 40 41 42 43 44 45 46 47
- 48 49 50 51 52 53 54 55
- 56 57 58 59 60 61 62 63
- 64 65 66 67 68 69 70 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 99 100 101 102 103
- 104 105 106 107 108 109 110 111
- 112 113 114 115 116 117 118 119
- 120 121 122 123 124 125 126 127
- 128 129 130 131 132 133 134 135
- 136 137 138 139 140 141 142 143
- 144 145 146 147 148 149 150 151
- 152 153 154 155 156 157 158 159
- 160 161 162 163 164 165 166 167
- 168 169 170 171 172 173 174 175
- 176 177 178 179 180 181 182 183
- 184 185 186 187 188 189 190 191
- 192 193 194 195 196 197 198 199
- 200 201 202 203 204 205 206 207
- 208 209 210 211 212 213 214 215
- 216 217 218 219 220 221 222 223
- 224 225 226 227 228 229 230 231
- 232 233 234 235 236 237 238 239
- 240 241 242 243 244 245 246 247
- 248 249 250 251 252 253 254 255>;
+ brightness-levels = <0 255>;
+ num-interpolated-steps = <255>;
default-brightness-level = <128>;
enable-gpios = <&gpio7 RK_PA2 GPIO_ACTIVE_HIGH>;
pinctrl-names = "default";
diff --git a/arch/arm/boot/dts/rk3288-veyron-jaq.dts b/arch/arm/boot/dts/rk3288-veyron-jaq.dts
index 80386203e85b..a4966e505a2f 100644
--- a/arch/arm/boot/dts/rk3288-veyron-jaq.dts
+++ b/arch/arm/boot/dts/rk3288-veyron-jaq.dts
@@ -20,39 +20,8 @@

&backlight {
/* Jaq panel PWM must be >= 3%, so start non-zero brightness at 8 */
- brightness-levels = <
- 0
- 8 9 10 11 12 13 14 15
- 16 17 18 19 20 21 22 23
- 24 25 26 27 28 29 30 31
- 32 33 34 35 36 37 38 39
- 40 41 42 43 44 45 46 47
- 48 49 50 51 52 53 54 55
- 56 57 58 59 60 61 62 63
- 64 65 66 67 68 69 70 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 99 100 101 102 103
- 104 105 106 107 108 109 110 111
- 112 113 114 115 116 117 118 119
- 120 121 122 123 124 125 126 127
- 128 129 130 131 132 133 134 135
- 136 137 138 139 140 141 142 143
- 144 145 146 147 148 149 150 151
- 152 153 154 155 156 157 158 159
- 160 161 162 163 164 165 166 167
- 168 169 170 171 172 173 174 175
- 176 177 178 179 180 181 182 183
- 184 185 186 187 188 189 190 191
- 192 193 194 195 196 197 198 199
- 200 201 202 203 204 205 206 207
- 208 209 210 211 212 213 214 215
- 216 217 218 219 220 221 222 223
- 224 225 226 227 228 229 230 231
- 232 233 234 235 236 237 238 239
- 240 241 242 243 244 245 246 247
- 248 249 250 251 252 253 254 255>;
+ brightness-levels = <0 8 255>;
+ num-interpolated-steps = <247>;
};

&rk808 {
diff --git a/arch/arm/boot/dts/rk3288-veyron-minnie.dts b/arch/arm/boot/dts/rk3288-veyron-minnie.dts
index 55955b082501..c833716dbe48 100644
--- a/arch/arm/boot/dts/rk3288-veyron-minnie.dts
+++ b/arch/arm/boot/dts/rk3288-veyron-minnie.dts
@@ -38,39 +38,8 @@

&backlight {
/* Minnie panel PWM must be >= 1%, so start non-zero brightness at 3 */
- brightness-levels = <
- 0 3 4 5 6 7
- 8 9 10 11 12 13 14 15
- 16 17 18 19 20 21 22 23
- 24 25 26 27 28 29 30 31
- 32 33 34 35 36 37 38 39
- 40 41 42 43 44 45 46 47
- 48 49 50 51 52 53 54 55
- 56 57 58 59 60 61 62 63
- 64 65 66 67 68 69 70 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 99 100 101 102 103
- 104 105 106 107 108 109 110 111
- 112 113 114 115 116 117 118 119
- 120 121 122 123 124 125 126 127
- 128 129 130 131 132 133 134 135
- 136 137 138 139 140 141 142 143
- 144 145 146 147 148 149 150 151
- 152 153 154 155 156 157 158 159
- 160 161 162 163 164 165 166 167
- 168 169 170 171 172 173 174 175
- 176 177 178 179 180 181 182 183
- 184 185 186 187 188 189 190 191
- 192 193 194 195 196 197 198 199
- 200 201 202 203 204 205 206 207
- 208 209 210 211 212 213 214 215
- 216 217 218 219 220 221 222 223
- 224 225 226 227 228 229 230 231
- 232 233 234 235 236 237 238 239
- 240 241 242 243 244 245 246 247
- 248 249 250 251 252 253 254 255>;
+ brightness-levels = <0 3 255>;
+ num-interpolated-steps = <252>;
};

&i2c_tunnel {
diff --git a/arch/arm/boot/dts/rk3288-veyron-tiger.dts b/arch/arm/boot/dts/rk3288-veyron-tiger.dts
index 27557203ae33..bebb230e592f 100644
--- a/arch/arm/boot/dts/rk3288-veyron-tiger.dts
+++ b/arch/arm/boot/dts/rk3288-veyron-tiger.dts
@@ -23,39 +23,8 @@

&backlight {
/* Tiger panel PWM must be >= 1%, so start non-zero brightness at 3 */
- brightness-levels = <
- 0 3 4 5 6 7
- 8 9 10 11 12 13 14 15
- 16 17 18 19 20 21 22 23
- 24 25 26 27 28 29 30 31
- 32 33 34 35 36 37 38 39
- 40 41 42 43 44 45 46 47
- 48 49 50 51 52 53 54 55
- 56 57 58 59 60 61 62 63
- 64 65 66 67 68 69 70 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 99 100 101 102 103
- 104 105 106 107 108 109 110 111
- 112 113 114 115 116 117 118 119
- 120 121 122 123 124 125 126 127
- 128 129 130 131 132 133 134 135
- 136 137 138 139 140 141 142 143
- 144 145 146 147 148 149 150 151
- 152 153 154 155 156 157 158 159
- 160 161 162 163 164 165 166 167
- 168 169 170 171 172 173 174 175
- 176 177 178 179 180 181 182 183
- 184 185 186 187 188 189 190 191
- 192 193 194 195 196 197 198 199
- 200 201 202 203 204 205 206 207
- 208 209 210 211 212 213 214 215
- 216 217 218 219 220 221 222 223
- 224 225 226 227 228 229 230 231
- 232 233 234 235 236 237 238 239
- 240 241 242 243 244 245 246 247
- 248 249 250 251 252 253 254 255>;
+ brightness-levels = <0 3 255>;
+ num-interpolated-steps = <252>;
};

&backlight_regulator {
--
2.23.0.444.g18eeb5a265-goog
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