clk: qcom: mdss: remove recalculation of vco rate for 10nm pll

In continuous splash use cases, the display is enabled in
the boot-loader. During display kernel probe, to enable clocks,
the rate is calculated by reading the hardware registers before
the corresponding software rate is set. At times when these rates
are nearly equal, the call for set rate never happens. This can
cause abnormal behavior. In this change during hand-off we don't
recalculate the clock rate to ensure the software programs the clock
registers accordingly.

Change-Id: Ibe512067a134856c4f4364f57a80d50214e88397
Signed-off-by: Ritesh Kumar <[email protected]>

pll/dsi_pll_10nm.c

@@ -1189,13 +1189,6 @@ static unsigned long vco_10nm_recalc_rate(struct clk_hw *hw,
 	struct dsi_pll_vco_clk *vco = to_vco_clk_hw(hw);
 	struct mdss_pll_resources *pll = vco->priv;
 	int rc;
-	u64 ref_clk = vco->ref_clk_rate;
-	u64 vco_rate;
-	u64 multiplier;
-	u32 frac;
-	u32 dec;
-	u32 outdiv;
-	u64 pll_freq, tmp64;
 
 	if (!vco->priv)
 		pr_err("vco priv is null\n");
@@ -1206,12 +1199,10 @@ static unsigned long vco_10nm_recalc_rate(struct clk_hw *hw,
 	}
 
 	/*
-	 * Calculate the vco rate from HW registers only for handoff cases.
-	 * For other cases where a vco_10nm_set_rate() has already been
-	 * called, just return the rate that was set earlier. This is due
-	 * to the fact that recalculating VCO rate requires us to read the
-	 * correct value of the pll_out_div divider clock, which is only set
-	 * afterwards.
+	 * In the case when vco arte is set, the recalculation function should
+	 * return the current rate as to avoid trying to set the vco rate
+	 * again. However durng handoff, recalculation should set the flag
+	 * according to the status of PLL.
 	 */
 	if (pll->vco_current_rate != 0) {
 		pr_debug("returning vco rate = %lld\n", pll->vco_current_rate);
@@ -1228,40 +1219,10 @@ static unsigned long vco_10nm_recalc_rate(struct clk_hw *hw,
 	if (!dsi_pll_10nm_lock_status(pll))
 		pll->handoff_resources = true;
 
-	dec = MDSS_PLL_REG_R(pll->pll_base, PLL_DECIMAL_DIV_START_1);
-	dec &= 0xFF;
-
-	frac = MDSS_PLL_REG_R(pll->pll_base, PLL_FRAC_DIV_START_LOW_1);
-	frac |= ((MDSS_PLL_REG_R(pll->pll_base, PLL_FRAC_DIV_START_MID_1) &
-		  0xFF) <<
-		8);
-	frac |= ((MDSS_PLL_REG_R(pll->pll_base, PLL_FRAC_DIV_START_HIGH_1) &
-		  0x3) <<
-		16);
-
-	/* OUTDIV_1:0 field is (log(outdiv, 2)) */
-	outdiv = MDSS_PLL_REG_R(pll->pll_base, PLL_PLL_OUTDIV_RATE);
-	outdiv &= 0x3;
-	outdiv = 1 << outdiv;
-
-	/*
-	 * TODO:
-	 *	1. Assumes prescaler is disabled
-	 *	2. Multiplier is 2^18. it should be 2^(num_of_frac_bits)
-	 **/
-	multiplier = 1 << 18;
-	pll_freq = dec * (ref_clk * 2);
-	tmp64 = (ref_clk * 2 * frac);
-	pll_freq += div_u64(tmp64, multiplier);
-
-	vco_rate = div_u64(pll_freq, outdiv);
-
-	pr_debug("dec=0x%x, frac=0x%x, outdiv=%d, vco=%llu\n",
-		 dec, frac, outdiv, vco_rate);
 
 	(void)mdss_pll_resource_enable(pll, false);
 
-	return (unsigned long)vco_rate;
+	return rc;
 }
 
 static int pixel_clk_get_div(void *context, unsigned int reg, unsigned int *div)