[PATCH v2 3/3] clk: meson: regmap: use the current divisor for read-only clocks

[Carlo Caione <ccaione@baylibre.com>]

None of the Meson clocks using clk_regmap_divider_ro_ops set
CLK_DIVIDER_READ_ONLY. Without that flag, the shared rounding callback
can choose a new divisor even though these ops cannot program it. The
clock core may then adjust child clocks using the wrong parent rate.

Make the read-only ops always round using the current hardware divisor.
Parent rate changes remain allowed with CLK_SET_RATE_PARENT.

Fixes: ea11dda9e091 ("clk: meson: add regmap clocks")
Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Carlo Caione <ccaione@baylibre.com>
---
 drivers/clk/meson/clk-regmap.c | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/clk/meson/clk-regmap.c b/drivers/clk/meson/clk-regmap.c
index 1ed56fe63cae..002e16865109 100644
--- a/drivers/clk/meson/clk-regmap.c
+++ b/drivers/clk/meson/clk-regmap.c
@@ -120,26 +120,34 @@ static unsigned long clk_regmap_div_recalc_rate(struct clk_hw *hw,
 				   div->width);
 }
 
-static int clk_regmap_div_determine_rate(struct clk_hw *hw,
-					 struct clk_rate_request *req)
+static int clk_regmap_div_ro_determine_rate(struct clk_hw *hw,
+					    struct clk_rate_request *req)
 {
 	struct clk_regmap *clk = to_clk_regmap(hw);
 	struct clk_regmap_div_data *div = clk_get_regmap_div_data(clk);
 	unsigned int val;
 	int ret;
 
-	/* if read only, just return current value */
-	if (div->flags & CLK_DIVIDER_READ_ONLY) {
-		ret = regmap_read(clk->map, div->offset, &val);
-		if (ret)
-			return ret;
+	ret = regmap_read(clk->map, div->offset, &val);
+	if (ret)
+		return ret;
 
-		val >>= div->shift;
-		val &= clk_div_mask(div->width);
+	val >>= div->shift;
+	val &= clk_div_mask(div->width);
 
-		return divider_ro_determine_rate(hw, req, div->table,
-						 div->width, div->flags, val);
-	}
+	return divider_ro_determine_rate(hw, req, div->table, div->width,
+					 div->flags, val);
+}
+
+static int clk_regmap_div_determine_rate(struct clk_hw *hw,
+					 struct clk_rate_request *req)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_div_data *div = clk_get_regmap_div_data(clk);
+
+	/* if read only, just return current value */
+	if (div->flags & CLK_DIVIDER_READ_ONLY)
+		return clk_regmap_div_ro_determine_rate(hw, req);
 
 	return divider_determine_rate(hw, req, div->table, div->width,
 				      div->flags);
@@ -176,7 +184,7 @@ EXPORT_SYMBOL_NS_GPL(clk_regmap_divider_ops, "CLK_MESON");
 const struct clk_ops clk_regmap_divider_ro_ops = {
 	.init = clk_regmap_init,
 	.recalc_rate = clk_regmap_div_recalc_rate,
-	.determine_rate = clk_regmap_div_determine_rate,
+	.determine_rate = clk_regmap_div_ro_determine_rate,
 };
 EXPORT_SYMBOL_NS_GPL(clk_regmap_divider_ro_ops, "CLK_MESON");
 

-- 
2.56.0


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