Hi Prakash, On 8/14/2012 6:53 PM, Manjunathappa, Prakash 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]> > --- > Applies on top of fbdev-next of Florian Tobias Schandinat's tree. > Since v2: > Optimized the lcd_disable_raster function. > Since v1: > Changed the commit message, also added link to hardware specification. > > drivers/video/da8xx-fb.c | 49 ++++++++++++++++++++++++++++++++++++--------- > 1 files changed, 39 insertions(+), 10 deletions(-) > > diff --git a/drivers/video/da8xx-fb.c b/drivers/video/da8xx-fb.c > index 7ae9d53..cb696ff 100644 > --- a/drivers/video/da8xx-fb.c > +++ b/drivers/video/da8xx-fb.c > @@ -48,6 +48,7 @@ > #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) > @@ -288,13 +289,41 @@ 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 stat_reg = LCD_STAT_REG; > + u32 loop_cnt = 0; > > 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) > + stat_reg = LCD_RAW_STAT_REG; > + > + if (wait_for_frame_done) { > + /* > + * 50 milli seconds should be sufficient for a frame to > + * complete > + */ > + loop_cnt = 50; > + while (!(lcdc_read(stat_reg) & LCD_FRAME_DONE)) { > + /* Handle timeout */ > + if (unlikely(0 == --loop_cnt)) { > + pr_err("LCD Controller timed out\n"); > + break; > + } > + mdelay(1); > + } > + }
The TRM you referenced in the patch description suggests waiting for frame done interrupt. Can we actually wait for the interrupt here instead of busy looping? Thanks, Sekhar _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
