[PATCH v2 1/1] fb i.MX23/28: Add the reset control of LCD

[PATCH v2 1/1] fb i.MX23/28: Add the reset control of LCD

[Gregory CLEMENT]

Video controller of STM allow to control the reset bit of an external
LCD controller. When reset_lcd is set, CTRL1_RESET bit is used to
enable and disable LCD.
Handle USE_LCD_RESET as a flag in imx_fb_platformdata.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
---
 arch/arm/mach-mxs/include/mach/fb.h |    3 +++
 drivers/video/stm.c                 |   11 +++++++++++
 2 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-mxs/include/mach/fb.h b/arch/arm/mach-mxs/include/mach/fb.h
index 2b61dee..2b6825f 100644
--- a/arch/arm/mach-mxs/include/mach/fb.h
+++ b/arch/arm/mach-mxs/include/mach/fb.h
@@ -31,6 +31,8 @@
 /** swap RGB to BGR */
 #define FB_SYNC_SWAP_RGB	(1 << 31)
 
+#define USE_LCD_RESET		1
+
 struct imx_fb_platformdata {
 	struct fb_videomode *mode_list;
 	unsigned mode_cnt;
@@ -42,6 +44,7 @@ struct imx_fb_platformdata {
 	void *fixed_screen;	/**< if != NULL use this as framebuffer memory */
 	unsigned fixed_screen_size; /**< framebuffer memory size for fixed_screen */
 
+	unsigned flags;
 	void (*enable)(int enable); /**< hook to enable backlight */
 };
 
diff --git a/drivers/video/stm.c b/drivers/video/stm.c
index 205cad1..ee2f026 100644
--- a/drivers/video/stm.c
+++ b/drivers/video/stm.c
@@ -48,6 +48,7 @@
 # define CTRL1_FIFO_CLEAR (1 << 21)
 # define SET_BYTE_PACKAGING(x) (((x) & 0xf) << 16)
 # define GET_BYTE_PACKAGING(x) (((x) >> 16) & 0xf)
+# define CTRL1_RESET (1 << 0)
 
 #ifdef CONFIG_ARCH_IMX28
 # define HW_LCDIF_CTRL2 0x20
@@ -253,6 +254,11 @@ static void stmfb_enable_controller(struct fb_info *fb_info)
 
 	/* stop FIFO reset */
 	writel(CTRL1_FIFO_CLEAR, fbi->base + HW_LCDIF_CTRL1 + BIT_CLR);
+
+	/* enable LCD using LCD_RESET signal*/
+	if (fbi->pdata->flags & USE_LCD_RESET)
+		writel(CTRL1_RESET,  fbi->base + HW_LCDIF_CTRL1 + BIT_SET);
+
 	/* start the engine right now */
 	writel(CTRL_RUN, fbi->base + HW_LCDIF_CTRL + BIT_SET);
 
@@ -266,6 +272,11 @@ static void stmfb_disable_controller(struct fb_info *fb_info)
 	unsigned loop;
 	uint32_t reg;
 
+
+	/* disable LCD using LCD_RESET signal*/
+	if (fbi->pdata->flags & USE_LCD_RESET)
+		writel(CTRL1_RESET,  fbi->base + HW_LCDIF_CTRL1 + BIT_CLR);
+
 	if (fbi->pdata->enable)
 		fbi->pdata->enable(0);
 
-- 
1.7.0.4



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