On Tue, Jul 24, 2012 at 9:39 AM, Manjunathappa, Prakash
<[email protected]> wrote:
>
> Wait for active frame transfer to complete after disabling LCDC.
> At the same this wait is not be required when there are sync and
> underflow errors.
> More information on disable and reset sequence can be found in
> section 13.4.6 of AM335x TRM @www.ti.com/am335x.
>
> Signed-off-by: Manjunathappa, Prakash <[email protected]>
> ---
> Patch applies on top of below patch under review:
> http://marc.info/?l=linux-fbdev&m=134280060828708&w=2
> "video: da8xx-fb: do clock reset of revision 2 LCDC before enabling"
> Since v1:
> Changed the commit message, also added link to hardware specification.
>
> drivers/video/da8xx-fb.c | 48
> ++++++++++++++++++++++++++++++++++++---------
> 1 files changed, 38 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/video/da8xx-fb.c b/drivers/video/da8xx-fb.c
> index a908dfd..0fb4d7d 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)
> @@ -279,13 +281,39 @@ 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));
Are you sure it should be do while? You call it from interrupt handler
too (sync lost handling). In that case mdelay() from interrupt
context..not a good idea I feel.
> +
> + 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;
return may not be necessary?
> + }
> }
>
> static void lcd_blit(int load_mode, struct da8xx_fb_par *par)
> @@ -626,7 +654,7 @@ 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(false);
>
> /* DMA has to be disabled */
> lcdc_write(0, LCD_DMA_CTRL_REG);
> @@ -724,7 +752,7 @@ static irqreturn_t lcdc_irq_handler_rev02(int irq,
> void *arg)
>
> if ((stat & LCD_SYNC_LOST) && (stat & LCD_FIFO_UNDERFLOW)) {
> pr_err("LCDC sync lost or underflow error occurred\n");
> - lcd_disable_raster();
> + lcd_disable_raster(false);
> lcdc_write(stat, LCD_MASKED_STAT_REG);
> lcd_enable_raster();
> } else if (stat & LCD_PL_LOAD_DONE) {
> @@ -734,7 +762,7 @@ 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(false);
>
> lcdc_write(stat, LCD_MASKED_STAT_REG);
>
> @@ -780,7 +808,7 @@ static irqreturn_t lcdc_irq_handler_rev01(int irq,
> void *arg)
>
> if ((stat & LCD_SYNC_LOST) && (stat & LCD_FIFO_UNDERFLOW)) {
> pr_err("LCDC sync lost or underflow error occurred\n");
> - lcd_disable_raster();
> + lcd_disable_raster(false);
> lcdc_write(stat, LCD_STAT_REG);
> lcd_enable_raster();
> } else if (stat & LCD_PL_LOAD_DONE) {
> @@ -790,7 +818,7 @@ 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(false);
>
> lcdc_write(stat, LCD_STAT_REG);
>
> @@ -887,7 +915,7 @@ 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(true);
> lcd_calc_clk_divider(par);
> lcd_enable_raster();
> }
> @@ -924,7 +952,7 @@ 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(true);
> lcdc_write(0, LCD_RASTER_CTRL_REG);
>
> /* disable DMA */
> @@ -1037,7 +1065,7 @@ 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(true);
> break;
> default:
> ret = -EINVAL;
> @@ -1377,7 +1405,7 @@ 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(true);
> clk_disable(par->lcdc_clk);
> console_unlock();
>
> --
> 1.7.1
>
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