linux-kernel - [PATCH v2 1/4] clk: qcom: clk-rcg2: Fail Duty-Cycle configuration if MND divider is not enabled.

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Date:   Sun, 12 Jun 2022 19:59:52 +0500
From:   Nikita Travkin <nikita@...n.ru>
To:     mturquette@...libre.com, sboyd@...nel.org, linus.walleij@...aro.org
Cc:     bjorn.andersson@...aro.org, agross@...nel.org, tdas@...eaurora.org,
        joonwoop@...eaurora.org, svarbanov@...sol.com,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        ~postmarketos/upstreaming@...ts.sr.ht,
        Nikita Travkin <nikita@...n.ru>
Subject: [PATCH v2 1/4] clk: qcom: clk-rcg2: Fail Duty-Cycle configuration if MND divider is not enabled.

In cases when MND is not enabled (e.g. when only Half Integer Divider is
used), setting D registers makes no effect.

Fail instead of making ineffective write.

Fixes: 7f891faf596e ("clk: qcom: clk-rcg2: Add support for duty-cycle for RCG")
Signed-off-by: Nikita Travkin <nikita@...n.ru>
---
 drivers/clk/qcom/clk-rcg2.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index 8e5dce09d162..2375e8122012 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -437,7 +437,7 @@ static int clk_rcg2_get_duty_cycle(struct clk_hw *hw, struct clk_duty *duty)
 static int clk_rcg2_set_duty_cycle(struct clk_hw *hw, struct clk_duty *duty)
 {
 	struct clk_rcg2 *rcg = to_clk_rcg2(hw);
-	u32 notn_m, n, m, d, not2d, mask, duty_per;
+	u32 notn_m, n, m, d, not2d, mask, duty_per, cfg;
 	int ret;
 
 	/* Duty-cycle cannot be modified for non-MND RCGs */
@@ -448,6 +448,11 @@ static int clk_rcg2_set_duty_cycle(struct clk_hw *hw, struct clk_duty *duty)
 
 	regmap_read(rcg->clkr.regmap, RCG_N_OFFSET(rcg), &notn_m);
 	regmap_read(rcg->clkr.regmap, RCG_M_OFFSET(rcg), &m);
+	regmap_read(rcg->clkr.regmap, RCG_CFG_OFFSET(rcg), &cfg);
+
+	/* Duty-cycle cannot be modified if MND divider is in bypass mode. */
+	if (!(cfg & CFG_MODE_MASK))
+		return -EINVAL;
 
 	n = (~(notn_m) + m) & mask;
 
-- 
2.35.3