video:da8xx-fb: Disable and reset sequence on version2 of LCDC

Patch follows the disable and software reset sequence specified
in version2 to LCDC functional specification.
Without this flicker is observed on re-enabling the LCDC.

Signed-off-by: Manjunathappa, Prakash <prakash.pm@ti.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

diff --git a/drivers/video/da8xx-fb.c b/drivers/video/da8xx-fb.c
index 55f91d9ab00bd18bd01df877eab846a310595956..29577bf1f559070044ee2c9f50d300d86745f78e 100644 (file)
--- a/drivers/video/da8xx-fb.c
+++ b/drivers/video/da8xx-fb.c
@@ -116,6 +116,7 @@
 /* Clock registers available only on Version 2 */
 #define  LCD_CLK_ENABLE_REG                    0x6c
 #define  LCD_CLK_RESET_REG                     0x70
+#define  LCD_CLK_MAIN_RESET                    BIT(3)
 
 #define LCD_NUM_BUFFERS        2
 
@@ -244,6 +245,10 @@ static inline void lcd_enable_raster(void)
 {
        u32 reg;
 
+       /* Bring LCDC out of reset */
+       if (lcd_revision == LCD_VERSION_2)
+               lcdc_write(0, LCD_CLK_RESET_REG);
+
        reg = lcdc_read(LCD_RASTER_CTRL_REG);
        if (!(reg & LCD_RASTER_ENABLE))
                lcdc_write(reg | LCD_RASTER_ENABLE, LCD_RASTER_CTRL_REG);
@@ -257,6 +262,10 @@ static inline void lcd_disable_raster(void)
        reg = lcdc_read(LCD_RASTER_CTRL_REG);
        if (reg & LCD_RASTER_ENABLE)
                lcdc_write(reg & ~LCD_RASTER_ENABLE, LCD_RASTER_CTRL_REG);
+
+       if (lcd_revision == LCD_VERSION_2)
+               /* Write 1 to reset LCDC */
+               lcdc_write(LCD_CLK_MAIN_RESET, LCD_CLK_RESET_REG);
 }
 
 static void lcd_blit(int load_mode, struct da8xx_fb_par *par)
@@ -584,8 +593,12 @@ static void lcd_reset(struct da8xx_fb_par *par)
        lcdc_write(0, LCD_DMA_CTRL_REG);
        lcdc_write(0, LCD_RASTER_CTRL_REG);
 
-       if (lcd_revision == LCD_VERSION_2)
+       if (lcd_revision == LCD_VERSION_2) {
                lcdc_write(0, LCD_INT_ENABLE_SET_REG);
+               /* Write 1 to reset */
+               lcdc_write(LCD_CLK_MAIN_RESET, LCD_CLK_RESET_REG);
+               lcdc_write(0, LCD_CLK_RESET_REG);
+       }
 }
 
 static void lcd_calc_clk_divider(struct da8xx_fb_par *par)