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From: "Manjunathappa, Prakash" <prakash.pm@ti.com>
To: <linux-fbdev@vger.kernel.org>
CC: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>,
	<davinci-linux-open-source@linux.davincidsp.com>,
	"Manjunathappa, Prakash" <prakash.pm@ti.com>
Subject: [PATCH] video: da8xx-fb: allow frame to complete before disabling
	LCDC
Date: Fri, 20 Jul 2012 21:21:56 +0530
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Wait for active frame transfer to complete before disabling LCDC.
At the same this wait is not be required when there are sync and
underflow errors.

Signed-off-by: Manjunathappa, Prakash <prakash.pm@ti.com>
---
 drivers/video/da8xx-fb.c |   58 ++++++++++++++++++++++++++++++++++++---------
 1 files changed, 46 insertions(+), 12 deletions(-)

diff --git a/drivers/video/da8xx-fb.c b/drivers/video/da8xx-fb.c
index 4440292..c178592 100644
--- a/drivers/video/da8xx-fb.c
+++ b/drivers/video/da8xx-fb.c
@@ -31,6 +31,7 @@
 #include <linux/cpufreq.h>
 #include <linux/console.h>
 #include <linux/slab.h>
+#include <linux/delay.h>
 #include <video/da8xx-fb.h>
 #include <asm/div64.h>
 
@@ -45,6 +46,7 @@
 #define LCD_PL_LOAD_DONE		BIT(6)
 #define LCD_FIFO_UNDERFLOW		BIT(5)
 #define LCD_SYNC_LOST			BIT(2)
+#define LCD_FRAME_DONE			BIT(0)
 
 /* LCD DMA Control Register */
 #define LCD_DMA_BURST_SIZE(x)		((x) << 4)
@@ -129,6 +131,8 @@
 #define RIGHT_MARGIN	64
 #define UPPER_MARGIN	32
 #define LOWER_MARGIN	32
+#define WAIT_FOR_FRAME_DONE	true
+#define NO_WAIT_FOR_FRAME_DONE	false
 
 static resource_size_t da8xx_fb_reg_base;
 static struct resource *lcdc_regs;
@@ -280,13 +284,39 @@ static inline void lcd_enable_raster(void)
 }
 
 /* Disable the Raster Engine of the LCD Controller */
-static inline void lcd_disable_raster(void)
+static inline void lcd_disable_raster(bool wait_for_frame_done)
 {
 	u32 reg;
+	u32 loop_cnt = 0;
+	u32 stat;
+	u32 i = 0;
+
+	/* 50 milli seconds should be sufficient for a frame to complete */
+	if (wait_for_frame_done)
+		loop_cnt = 50;
 
 	reg = lcdc_read(LCD_RASTER_CTRL_REG);
 	if (reg & LCD_RASTER_ENABLE)
 		lcdc_write(reg & ~LCD_RASTER_ENABLE, LCD_RASTER_CTRL_REG);
+
+	/* Wait for the current frame to complete */
+	do {
+		if (lcd_revision == LCD_VERSION_1)
+			stat = lcdc_read(LCD_STAT_REG);
+		else
+			stat = lcdc_read(LCD_RAW_STAT_REG);
+		mdelay(1);
+	} while (!(stat & LCD_FRAME_DONE) && (i++ < loop_cnt));
+
+	if (lcd_revision == LCD_VERSION_1)
+		lcdc_write(stat, LCD_STAT_REG);
+	else
+		lcdc_write(stat, LCD_MASKED_STAT_REG);
+
+	if ((loop_cnt != 0) && (i >= loop_cnt)) {
+		pr_err("LCD Controller timed out\n");
+		return;
+	}
 }
 
 static void lcd_blit(int load_mode, struct da8xx_fb_par *par)
@@ -663,7 +693,7 @@ static int fb_setcolreg(unsigned regno, unsigned red, unsigned green,
 static void lcd_reset(struct da8xx_fb_par *par)
 {
 	/* Disable the Raster if previously Enabled */
-	lcd_disable_raster();
+	lcd_disable_raster(NO_WAIT_FOR_FRAME_DONE);
 
 	/* DMA has to be disabled */
 	lcdc_write(0, LCD_DMA_CTRL_REG);
@@ -760,7 +790,8 @@ static irqreturn_t lcdc_irq_handler_rev02(int irq, void *arg)
 	u32 reg_int;
 
 	if ((stat & LCD_SYNC_LOST) && (stat & LCD_FIFO_UNDERFLOW)) {
-		lcd_disable_raster();
+		pr_err("LCDC sync lost or underflow error occured\n");
+		lcd_disable_raster(NO_WAIT_FOR_FRAME_DONE);
 		lcdc_write(stat, LCD_MASKED_STAT_REG);
 		lcd_enable_raster();
 	} else if (stat & LCD_PL_LOAD_DONE) {
@@ -770,7 +801,7 @@ static irqreturn_t lcdc_irq_handler_rev02(int irq, void *arg)
 		 * interrupt via the following write to the status register. If
 		 * this is done after then one gets multiple PL done interrupts.
 		 */
-		lcd_disable_raster();
+		lcd_disable_raster(NO_WAIT_FOR_FRAME_DONE);
 
 		lcdc_write(stat, LCD_MASKED_STAT_REG);
 
@@ -815,7 +846,8 @@ static irqreturn_t lcdc_irq_handler_rev01(int irq, void *arg)
 	u32 reg_ras;
 
 	if ((stat & LCD_SYNC_LOST) && (stat & LCD_FIFO_UNDERFLOW)) {
-		lcd_disable_raster();
+		pr_err("LCDC sync lost or underflow error occured\n");
+		lcd_disable_raster(NO_WAIT_FOR_FRAME_DONE);
 		lcdc_write(stat, LCD_STAT_REG);
 		lcd_enable_raster();
 	} else if (stat & LCD_PL_LOAD_DONE) {
@@ -825,7 +857,7 @@ static irqreturn_t lcdc_irq_handler_rev01(int irq, void *arg)
 		 * interrupt via the following write to the status register. If
 		 * this is done after then one gets multiple PL done interrupts.
 		 */
-		lcd_disable_raster();
+		lcd_disable_raster(NO_WAIT_FOR_FRAME_DONE);
 
 		lcdc_write(stat, LCD_STAT_REG);
 
@@ -945,7 +977,7 @@ static int lcd_da8xx_cpufreq_transition(struct notifier_block *nb,
 	if (val == CPUFREQ_POSTCHANGE) {
 		if (par->lcd_fck_rate != clk_get_rate(par->lcdc_clk)) {
 			par->lcd_fck_rate = clk_get_rate(par->lcdc_clk);
-			lcd_disable_raster();
+			lcd_disable_raster(WAIT_FOR_FRAME_DONE);
 			lcd_calc_clk_divider(par);
 			lcd_enable_raster();
 		}
@@ -982,7 +1014,7 @@ static int __devexit fb_remove(struct platform_device *dev)
 		if (par->panel_power_ctrl)
 			par->panel_power_ctrl(0);
 
-		lcd_disable_raster();
+		lcd_disable_raster(WAIT_FOR_FRAME_DONE);
 		lcdc_write(0, LCD_RASTER_CTRL_REG);
 
 		/* disable DMA  */
@@ -1095,7 +1127,7 @@ static int cfb_blank(int blank, struct fb_info *info)
 		if (par->panel_power_ctrl)
 			par->panel_power_ctrl(0);
 
-		lcd_disable_raster();
+		lcd_disable_raster(WAIT_FOR_FRAME_DONE);
 		break;
 	default:
 		ret = -EINVAL;
@@ -1435,7 +1467,7 @@ static int fb_suspend(struct platform_device *dev, pm_message_t state)
 		par->panel_power_ctrl(0);
 
 	fb_set_suspend(info, 1);
-	lcd_disable_raster();
+	lcd_disable_raster(WAIT_FOR_FRAME_DONE);
 	clk_disable(par->lcdc_clk);
 	console_unlock();
 
@@ -1447,11 +1479,13 @@ static int fb_resume(struct platform_device *dev)
 	struct da8xx_fb_par *par = info->par;
 
 	console_lock();
-	if (par->panel_power_ctrl)
-		par->panel_power_ctrl(1);
 
 	clk_enable(par->lcdc_clk);
+	usleep_range(1000, 2000);
 	lcd_enable_raster();
+	if (par->panel_power_ctrl)
+		par->panel_power_ctrl(1);
+
 	fb_set_suspend(info, 0);
 	console_unlock();