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Commit ff12c729 authored by Padmanabhan Komanduru's avatar Padmanabhan Komanduru Committed by Gerrit - the friendly Code Review server
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clk: qcom: check for change in RCG configuration during set_rate 



For DSI byte clock RCG, check if there is a change in existing
settings before updating RCG configuration. This is needed to
avoid glitch on the display panel when there is a change in the
DSI byte clock frequency with display enabled.

Change-Id: I8ef0331cbb466b399cd12199b4d335ed44997dbc
Signed-off-by: default avatarPadmanabhan Komanduru <pkomandu@codeaurora.org>
parent 85141748

drivers/clk/qcom/clk-rcg2.c

+35 −0
Original line number Diff line number Diff line
@@ -336,6 +336,39 @@ static int clk_rcg2_determine_rate(struct clk_hw *hw, 
	return _freq_tbl_determine_rate(hw, rcg->freq_tbl, req);

}



static bool clk_rcg2_current_config(struct clk_rcg2 *rcg,

				    const struct freq_tbl *f)

{

	struct clk_hw *hw = &rcg->clkr.hw;

	u32 cfg, mask, new_cfg;

	int index;



	if (rcg->mnd_width) {

		mask = BIT(rcg->mnd_width) - 1;

		regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + M_REG, &cfg);

		if ((cfg & mask) != (f->m & mask))

			return false;



		regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + N_REG, &cfg);

		if ((cfg & mask) != (~(f->n - f->m) & mask))

			return false;

	}



	mask = (BIT(rcg->hid_width) - 1) | CFG_SRC_SEL_MASK;



	index = qcom_find_src_index(hw, rcg->parent_map, f->src);



	new_cfg = ((f->pre_div << CFG_SRC_DIV_SHIFT) |

		(rcg->parent_map[index].cfg << CFG_SRC_SEL_SHIFT)) & mask;



	regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG, &cfg);



	if (new_cfg != (cfg & mask))

		return false;



	return true;

}



static int clk_rcg2_configure(struct clk_rcg2 *rcg, const struct freq_tbl *f)

{

	u32 cfg, mask;
@@ -900,6 +933,8 @@ static int clk_byte2_set_rate(struct clk_hw *hw, unsigned long rate, 
	for (i = 0; i < num_parents; i++) {

		if (cfg == rcg->parent_map[i].cfg) {

			f.src = rcg->parent_map[i].src;

			if (clk_rcg2_current_config(rcg, &f))

				return 0;

			return clk_rcg2_configure(rcg, &f);

		}

	}