drivers/video/fbdev/aty/radeon_backlight.c

Source file repositories/reference/linux-study-clean/drivers/video/fbdev/aty/radeon_backlight.c

File Facts

System
Linux kernel
Corpus path
drivers/video/fbdev/aty/radeon_backlight.c
Extension
.c
Size
5852 bytes
Lines
209
Domain
Driver Families
Bucket
drivers/video
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct radeon_bl_privdata {
	struct radeonfb_info *rinfo;
	uint8_t negative;
};

static int radeon_bl_get_level_brightness(struct radeon_bl_privdata *pdata,
		int level)
{
	int rlevel;

	/* Get and convert the value */
	/* No locking of bl_curve since we read a single value */
	rlevel = pdata->rinfo->info->bl_curve[level] *
		 FB_BACKLIGHT_MAX / MAX_RADEON_LEVEL;

	if (rlevel < 0)
		rlevel = 0;
	else if (rlevel > MAX_RADEON_LEVEL)
		rlevel = MAX_RADEON_LEVEL;

	if (pdata->negative)
		rlevel = MAX_RADEON_LEVEL - rlevel;

	return rlevel;
}

static int radeon_bl_update_status(struct backlight_device *bd)
{
	struct radeon_bl_privdata *pdata = bl_get_data(bd);
	struct radeonfb_info *rinfo = pdata->rinfo;
	u32 lvds_gen_cntl, tmpPixclksCntl;
	int level;

	if (rinfo->mon1_type != MT_LCD)
		return 0;

	/* We turn off the LCD completely instead of just dimming the
	 * backlight. This provides some greater power saving and the display
	 * is useless without backlight anyway.
	 */
	level = backlight_get_brightness(bd);

	timer_delete_sync(&rinfo->lvds_timer);
	radeon_engine_idle();

	lvds_gen_cntl = INREG(LVDS_GEN_CNTL);
	if (level > 0) {
		lvds_gen_cntl &= ~LVDS_DISPLAY_DIS;
		if (!(lvds_gen_cntl & LVDS_BLON) || !(lvds_gen_cntl & LVDS_ON)) {
			lvds_gen_cntl |= (rinfo->init_state.lvds_gen_cntl & LVDS_DIGON);
			lvds_gen_cntl |= LVDS_BLON | LVDS_EN;
			OUTREG(LVDS_GEN_CNTL, lvds_gen_cntl);
			lvds_gen_cntl &= ~LVDS_BL_MOD_LEVEL_MASK;
			lvds_gen_cntl |=
				(radeon_bl_get_level_brightness(pdata, level) <<
				 LVDS_BL_MOD_LEVEL_SHIFT);
			lvds_gen_cntl |= LVDS_ON;
			lvds_gen_cntl |= (rinfo->init_state.lvds_gen_cntl & LVDS_BL_MOD_EN);
			rinfo->pending_lvds_gen_cntl = lvds_gen_cntl;
			mod_timer(&rinfo->lvds_timer,
				  jiffies + msecs_to_jiffies(rinfo->panel_info.pwr_delay));
		} else {
			lvds_gen_cntl &= ~LVDS_BL_MOD_LEVEL_MASK;
			lvds_gen_cntl |=
				(radeon_bl_get_level_brightness(pdata, level) <<
				 LVDS_BL_MOD_LEVEL_SHIFT);
			OUTREG(LVDS_GEN_CNTL, lvds_gen_cntl);
		}
		rinfo->init_state.lvds_gen_cntl &= ~LVDS_STATE_MASK;
		rinfo->init_state.lvds_gen_cntl |= rinfo->pending_lvds_gen_cntl
			& LVDS_STATE_MASK;
	} else {
		/* Asic bug, when turning off LVDS_ON, we have to make sure
		   RADEON_PIXCLK_LVDS_ALWAYS_ON bit is off
		*/
		tmpPixclksCntl = INPLL(PIXCLKS_CNTL);
		if (rinfo->is_mobility || rinfo->is_IGP)
			OUTPLLP(PIXCLKS_CNTL, 0, ~PIXCLK_LVDS_ALWAYS_ONb);
		lvds_gen_cntl &= ~(LVDS_BL_MOD_LEVEL_MASK | LVDS_BL_MOD_EN);
		lvds_gen_cntl |= (radeon_bl_get_level_brightness(pdata, 0) <<
				  LVDS_BL_MOD_LEVEL_SHIFT);
		lvds_gen_cntl |= LVDS_DISPLAY_DIS;
		OUTREG(LVDS_GEN_CNTL, lvds_gen_cntl);
		udelay(100);
		lvds_gen_cntl &= ~(LVDS_ON | LVDS_EN);
		OUTREG(LVDS_GEN_CNTL, lvds_gen_cntl);
		lvds_gen_cntl &= ~(LVDS_DIGON);
		rinfo->pending_lvds_gen_cntl = lvds_gen_cntl;
		mod_timer(&rinfo->lvds_timer,
			  jiffies + msecs_to_jiffies(rinfo->panel_info.pwr_delay));

Annotation

Implementation Notes