bdk: display: use spare reg to store dcs bl duty

And also remove backlight pwm restoring from coreboot hw deinit path.

bdk/display/di.c

@@ -33,10 +33,9 @@
 
 #include "di.inl"
 
-static u32  _panel_id_raw = 0;
-static u32  _panel_id      = 0;
-static u32  _dsi_bl        = -1;
 static bool _nx_aula      = false;
+static u32  _panel_id     = 0;
+static u32  _panel_id_raw = 0;
 
 static void _display_panel_and_hw_end(bool no_panel_deinit);
 
@@ -366,7 +365,7 @@ void display_init()
 	CLOCK(CLK_RST_CONTROLLER_CLK_ENB_L_SET) = BIT(CLK_L_DISP1);
 
 	CLOCK(CLK_RST_CONTROLLER_CLK_ENB_X_SET) = BIT(CLK_X_UART_FST_MIPI_CAL);
-	CLOCK(CLK_RST_CONTROLLER_CLK_SOURCE_UART_FST_MIPI_CAL) = CLK_SRC_DIV(6); // Set PLLP_OUT3 and div 6 (68MHz).
+	CLOCK(CLK_RST_CONTROLLER_CLK_SOURCE_UART_FST_MIPI_CAL) = CLK_SRC_DIV(6); // Set PLLP_OUT3 and div 6 (17MHz).
 
 	CLOCK(CLK_RST_CONTROLLER_CLK_ENB_W_SET) = BIT(CLK_W_DSIA_LP);
 	CLOCK(CLK_RST_CONTROLLER_CLK_SOURCE_DSIA_LP) = CLK_SRC_DIV(6);           // Set PLLP_OUT  and div 6 (68MHz).
@@ -491,7 +490,6 @@ void display_init()
 		DSI(_DSIREG(DSI_WR_DATA)) = 0x000051; // MIPI_DCS_SET_BRIGHTNESS 0000: 0%. FF07: 100%.
 		DSI(_DSIREG(DSI_TRIGGER)) = DSI_TRIGGER_HOST;
 		usleep(5000);
-		_dsi_bl = 0;
 		break;
 
 	case PANEL_JDI_XXX062M:
@@ -608,7 +606,7 @@ void display_backlight(bool enable)
 
 static void _display_dsi_backlight_brightness(u32 duty)
 {
-	if (_dsi_bl == duty)
+	if (DISPLAY_A(_DIREG(DC_DISP_BACKLIGHT_DUTY)) == duty)
 		return;
 
 	// Convert duty to candela.
@@ -621,7 +619,7 @@ static void _display_dsi_backlight_brightness(u32 duty)
 	if (!duty)
 		usleep(100000);
 
-	_dsi_bl = duty;
+	DISPLAY_A(_DIREG(DC_DISP_BACKLIGHT_DUTY)) = duty;
 }
 
 static void _display_pwm_backlight_brightness(u32 duty, u32 step_delay)
@@ -661,14 +659,6 @@ void display_backlight_brightness(u32 brightness, u32 step_delay)
 		_display_dsi_backlight_brightness(brightness);
 }
 
-u32 display_get_backlight_brightness()
-{
-	if (_panel_id != PANEL_SAM_AMS699VC01)
-		return ((PWM(PWM_CONTROLLER_PWM_CSR_0) >> 16) & 0xFF);
-	else
-		return _dsi_bl;
-}
-
 static void _display_panel_and_hw_end(bool no_panel_deinit)
 {
 	if (no_panel_deinit)

bdk/display/di.h

@@ -291,7 +291,6 @@
 #define  CURSOR_SIZE_128 (2 << 24)
 #define  CURSOR_SIZE_256 (3 << 24)
 #define DC_DISP_CURSOR_POSITION         0x440
-#define DC_DISP_BLEND_BACKGROUND_COLOR 0x4E4
 #define DC_DISP_CURSOR_START_ADDR_HI    0x4EC
 #define DC_DISP_CURSOR_START_ADDR_HI_NS 0x4ED
 #define DC_DISP_BLEND_CURSOR_CONTROL    0x4F1
@@ -309,6 +308,10 @@
 #define DC_DISP_SD_BL_CONTROL          0x4DC
 #define DC_DISP_BLEND_BACKGROUND_COLOR 0x4E4
 
+#define DC_DISP_DISPLAY_SPARE0         0x4F7 // Used by SW.
+#define DC_DISP_DISPLAY_SPARE1         0x4F8
+#define DC_DISP_BACKLIGHT_DUTY         DC_DISP_DISPLAY_SPARE1
+
 #define DC_WINC_COLOR_PALETTE 0x500
 #define  COLOR_PALETTE_IDX(off) (DC_WINC_COLOR_PALETTE + (off))
 #define  COLOR_PALETTE_RGB(rgb) (byte_swap_32(rgb) >> 8)
@@ -884,10 +887,9 @@ void display_dsi_vblank_write(u8 cmd, u32 len, void *data);
 /*! Show one single color on the display. */
 void display_color_screen(u32 color);
 
-/*! Switches screen backlight ON/OFF. */
+/*! Screen backlight ON/OFF or set via duty and fading. */
 void display_backlight(bool enable);
 void display_backlight_brightness(u32 brightness, u32 step_delay);
-u32  display_get_backlight_brightness();
 
 u32 *display_init_window_a_pitch();
 u32 *display_init_window_a_pitch_vic();

bdk/soc/hw_init.c

@@ -520,11 +520,9 @@ void hw_deinit(bool coreboot, u32 bl_magic)
 	switch (bl_magic)
 	{
 	case BL_MAGIC_CRBOOT_SLD:;
-		// Set pwm to 0%, switch to gpio mode and restore pwm duty.
+		// Set pwm to 0% and switch to gpio mode.
-		u32 brightness = display_get_backlight_brightness();
 		display_backlight_brightness(0, 1000);
 		gpio_config(GPIO_PORT_V, GPIO_PIN_0, GPIO_MODE_GPIO);
-		display_backlight_brightness(brightness, 0);
 		break;
 	case BL_MAGIC_L4TLDR_SLD:
 		// Do not disable display or backlight at all.