shell: configure Standard backlight intensity per board

Add BACKLIGHT_STANDARD_INTENSITY with a 1-100 range and a default of 50.
Set it to 25 in the shared Getafix board configuration and use it for
the Standard preset, which also supplies fresh-device brightness.

Keep Standard as the default mode and preserve saved preferences.
Battery Saver retains its Dim curve and other boards retain 50%.

Fixes FIRM-4392

Co-Authored-By: GPT-6 Astra <noreply@openai.com>
Signed-off-by: Joshua Jun <lets@throw.rocks>

Author: jplexer

boards/getafix/defconfig

@@ -74,6 +74,7 @@ CONFIG_RNG=y
 
 
 CONFIG_DYNAMIC_BACKLIGHT=y
+CONFIG_BACKLIGHT_STANDARD_INTENSITY=25
 CONFIG_ACCEL_SENSITIVITY=y
 CONFIG_APP_SCALING=y
 CONFIG_ORIENTATION_MANAGER=y

src/fw/Kconfig

@@ -18,6 +18,15 @@ config THEMING
     help
       Expose the highlight-color theming UI under Settings.
 
+config BACKLIGHT_STANDARD_INTENSITY
+    int "Standard backlight preset intensity (%)"
+    range 1 100
+    default 50
+    help
+      Logical brightness used by the Standard backlight preset and fresh
+      shell preferences. The light service scales it to the board hardware
+      maximum. Saved brightness preferences take precedence.
+
 config DYNAMIC_BACKLIGHT
     bool "Dynamic backlight"
     help

src/fw/shell/normal/prefs.c

@@ -76,7 +76,6 @@ static uint32_t s_backlight_timeout_ms = DEFAULT_BACKLIGHT_TIMEOUT_MS;
 #define BACKLIGHT_INTENSITY_MIN 1U
 #define BACKLIGHT_INTENSITY_MAX 100U
 #define BACKLIGHT_INTENSITY_MEDIUM 25U
-#define BACKLIGHT_INTENSITY_HIGH 50U
 #define BACKLIGHT_INTENSITY_DEFAULT BACKLIGHT_INTENSITY_MEDIUM
 static uint8_t s_backlight_intensity; // default set in shell_prefs_init()
 
@@ -142,7 +141,7 @@ static const BacklightPresetSettings s_backlight_preset_settings[] = {
 #ifdef CONFIG_DYNAMIC_BACKLIGHT
     .dynamic_mode = BacklightDynamicMode_Standard,
 #endif
-    .intensity = BACKLIGHT_INTENSITY_HIGH,
+    .intensity = CONFIG_BACKLIGHT_STANDARD_INTENSITY,
     .timeout_ms = DEFAULT_BACKLIGHT_TIMEOUT_MS,
     .motion_enabled = true,
     .touch_wake = BacklightTouchWake_DoubleTap,

tests/CMakeLists.txt

@@ -50,6 +50,7 @@ add_compile_options(${PBL_TEST_C_FLAGS})
 set(PBL_TEST_DEFINES
   "CLAR_FIXTURE_PATH=\"${PBL_BASE}/tests/fixtures/\""
   CONFIG_LOG=1
+  CONFIG_BACKLIGHT_STANDARD_INTENSITY=50
   CONFIG_KERNEL_NUM_PRIORITIES=5
   CONFIG_KERNEL_THREAD_TLS_SLOTS=2
   CONFIG_KERNEL_STACK_ALIGN=8