clk: qcom: clk-alpha-pll: Do not use random stack value for recalc rate

If regmap_read() fails, random stack value was used in calculating new
frequency in recalc_rate() callbacks.  Such failure is really not
expected as these are all MMIO reads, however code should be here
correct and bail out.  This also avoids possible warning on
uninitialized value.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250212-b4-clk-qcom-clean-v3-1-499f37444f5d@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Author: krzk

drivers/clk/qcom/clk-alpha-pll.c

@@ -709,14 +709,19 @@ clk_alpha_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
 	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
 	u32 alpha_width = pll_alpha_width(pll);
 
-	regmap_read(pll->clkr.regmap, PLL_L_VAL(pll), &l);
+	if (regmap_read(pll->clkr.regmap, PLL_L_VAL(pll), &l))
+		return 0;
+
+	if (regmap_read(pll->clkr.regmap, PLL_USER_CTL(pll), &ctl))
+		return 0;
 
-	regmap_read(pll->clkr.regmap, PLL_USER_CTL(pll), &ctl);
 	if (ctl & PLL_ALPHA_EN) {
-		regmap_read(pll->clkr.regmap, PLL_ALPHA_VAL(pll), &low);
+		if (regmap_read(pll->clkr.regmap, PLL_ALPHA_VAL(pll), &low))
+			return 0;
 		if (alpha_width > 32) {
-			regmap_read(pll->clkr.regmap, PLL_ALPHA_VAL_U(pll),
-				    &high);
+			if (regmap_read(pll->clkr.regmap, PLL_ALPHA_VAL_U(pll),
+					&high))
+				return 0;
 			a = (u64)high << 32 | low;
 		} else {
 			a = low & GENMASK(alpha_width - 1, 0);
@@ -942,8 +947,11 @@ alpha_pll_huayra_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
 	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
 	u32 l, alpha = 0, ctl, alpha_m, alpha_n;
 
-	regmap_read(pll->clkr.regmap, PLL_L_VAL(pll), &l);
-	regmap_read(pll->clkr.regmap, PLL_USER_CTL(pll), &ctl);
+	if (regmap_read(pll->clkr.regmap, PLL_L_VAL(pll), &l))
+		return 0;
+
+	if (regmap_read(pll->clkr.regmap, PLL_USER_CTL(pll), &ctl))
+		return 0;
 
 	if (ctl & PLL_ALPHA_EN) {
 		regmap_read(pll->clkr.regmap, PLL_ALPHA_VAL(pll), &alpha);
@@ -1137,8 +1145,11 @@ clk_trion_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
 	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
 	u32 l, frac, alpha_width = pll_alpha_width(pll);
 
-	regmap_read(pll->clkr.regmap, PLL_L_VAL(pll), &l);
-	regmap_read(pll->clkr.regmap, PLL_ALPHA_VAL(pll), &frac);
+	if (regmap_read(pll->clkr.regmap, PLL_L_VAL(pll), &l))
+		return 0;
+
+	if (regmap_read(pll->clkr.regmap, PLL_ALPHA_VAL(pll), &frac))
+		return 0;
 
 	return alpha_pll_calc_rate(parent_rate, l, frac, alpha_width);
 }
@@ -1196,7 +1207,8 @@ clk_alpha_pll_postdiv_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
 	struct clk_alpha_pll_postdiv *pll = to_clk_alpha_pll_postdiv(hw);
 	u32 ctl;
 
-	regmap_read(pll->clkr.regmap, PLL_USER_CTL(pll), &ctl);
+	if (regmap_read(pll->clkr.regmap, PLL_USER_CTL(pll), &ctl))
+		return 0;
 
 	ctl >>= PLL_POST_DIV_SHIFT;
 	ctl &= PLL_POST_DIV_MASK(pll);
@@ -1412,8 +1424,11 @@ static unsigned long alpha_pll_fabia_recalc_rate(struct clk_hw *hw,
 	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
 	u32 l, frac, alpha_width = pll_alpha_width(pll);
 
-	regmap_read(pll->clkr.regmap, PLL_L_VAL(pll), &l);
-	regmap_read(pll->clkr.regmap, PLL_FRAC(pll), &frac);
+	if (regmap_read(pll->clkr.regmap, PLL_L_VAL(pll), &l))
+		return 0;
+
+	if (regmap_read(pll->clkr.regmap, PLL_FRAC(pll), &frac))
+		return 0;
 
 	return alpha_pll_calc_rate(parent_rate, l, frac, alpha_width);
 }
@@ -1563,7 +1578,8 @@ clk_trion_pll_postdiv_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
 	struct regmap *regmap = pll->clkr.regmap;
 	u32 i, div = 1, val;
 
-	regmap_read(regmap, PLL_USER_CTL(pll), &val);
+	if (regmap_read(regmap, PLL_USER_CTL(pll), &val))
+		return 0;
 
 	val >>= pll->post_div_shift;
 	val &= PLL_POST_DIV_MASK(pll);
@@ -2484,9 +2500,12 @@ static unsigned long alpha_pll_lucid_evo_recalc_rate(struct clk_hw *hw,
 	struct regmap *regmap = pll->clkr.regmap;
 	u32 l, frac;
 
-	regmap_read(regmap, PLL_L_VAL(pll), &l);
+	if (regmap_read(regmap, PLL_L_VAL(pll), &l))
+		return 0;
 	l &= LUCID_EVO_PLL_L_VAL_MASK;
-	regmap_read(regmap, PLL_ALPHA_VAL(pll), &frac);
+
+	if (regmap_read(regmap, PLL_ALPHA_VAL(pll), &frac))
+		return 0;
 
 	return alpha_pll_calc_rate(parent_rate, l, frac, pll_alpha_width(pll));
 }
@@ -2699,7 +2718,8 @@ static unsigned long clk_rivian_evo_pll_recalc_rate(struct clk_hw *hw,
 	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
 	u32 l;
 
-	regmap_read(pll->clkr.regmap, PLL_L_VAL(pll), &l);
+	if (regmap_read(pll->clkr.regmap, PLL_L_VAL(pll), &l))
+		return 0;
 
 	return parent_rate * l;
 }