linux-kernel - [PATCH] clk: si5341: fix reported clk

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Date:   Fri, 03 Dec 2021 14:12:07 +0000
From:   Adam Wujek <dev_public@...ek.eu>
To:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     Adam Wujek <dev_public@...ek.eu>, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] clk: si5341: fix reported clk_rate when output divider is 2

SI5341_OUT_CFG_RDIV_FORCE2 shall be checked first to distinguish whether
a divider for a given output is set to 2 (SI5341_OUT_CFG_RDIV_FORCE2
is set) or the output is disabled (SI5341_OUT_CFG_RDIV_FORCE2 not set,
SI5341_OUT_R_REG is set 0).
Before the change, divider set to 2 (SI5341_OUT_R_REG set to 0) was
interpreted as output is disabled.

Signed-off-by: Adam Wujek <dev_public@...ek.eu>
---
 drivers/clk/clk-si5341.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/clk/clk-si5341.c b/drivers/clk/clk-si5341.c
index b7641abe6747..15b1c90cafe5 100644
--- a/drivers/clk/clk-si5341.c
+++ b/drivers/clk/clk-si5341.c
@@ -798,6 +798,15 @@ static unsigned long si5341_output_clk_recalc_rate(struct clk_hw *hw,
 	u32 r_divider;
 	u8 r[3];

+	err = regmap_read(output->data->regmap,
+			SI5341_OUT_CONFIG(output), &val);
+	if (err < 0)
+		return err;
+
+	/* If SI5341_OUT_CFG_RDIV_FORCE2 is set, r_divider is 2 */
+	if (val & SI5341_OUT_CFG_RDIV_FORCE2)
+		return parent_rate / 2;
+
 	err = regmap_bulk_read(output->data->regmap,
 			SI5341_OUT_R_REG(output), r, 3);
 	if (err < 0)
@@ -814,13 +823,6 @@ static unsigned long si5341_output_clk_recalc_rate(struct clk_hw *hw,
 	r_divider += 1;
 	r_divider <<= 1;

-	err = regmap_read(output->data->regmap,
-			SI5341_OUT_CONFIG(output), &val);
-	if (err < 0)
-		return err;
-
-	if (val & SI5341_OUT_CFG_RDIV_FORCE2)
-		r_divider = 2;

 	return parent_rate / r_divider;
 }
--
2.25.1