linux-kernel - [PATCH 06/37] clk: renesas: rzg2l: wait for status bit of SD mux before continuing

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Message-Id: <20230912045157.177966-7-claudiu.beznea.uj@bp.renesas.com>
Date:   Tue, 12 Sep 2023 07:51:26 +0300
From:   Claudiu <claudiu.beznea@...on.dev>
To:     geert+renesas@...der.be, mturquette@...libre.com, sboyd@...nel.org,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        conor+dt@...nel.org, ulf.hansson@...aro.org,
        linus.walleij@...aro.org, gregkh@...uxfoundation.org,
        jirislaby@...nel.org, magnus.damm@...il.com,
        catalin.marinas@....com, will@...nel.org,
        prabhakar.mahadev-lad.rj@...renesas.com,
        biju.das.jz@...renesas.com, quic_bjorande@...cinc.com,
        arnd@...db.de, konrad.dybcio@...aro.org, neil.armstrong@...aro.org,
        nfraprado@...labora.com, rafal@...ecki.pl,
        wsa+renesas@...g-engineering.com
Cc:     linux-renesas-soc@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mmc@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-serial@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: [PATCH 06/37] clk: renesas: rzg2l: wait for status bit of SD mux before continuing

From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>

Hardware user manual of RZ/G2L (r01uh0914ej0130-rzg2l-rzg2lc.pdf,
chapter 7.4.7 Procedure for Switching Clocks by the Dynamic Switching
Frequency Selectors) specifies that we need to check CPG_PL2SDHI_DSEL for
SD clock switching status.

Fixes: eaff33646f4cb ("clk: renesas: rzg2l: Add SDHI clk mux support")
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
---
 drivers/clk/renesas/rzg2l-cpg.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c
index 47f488387f33..70d1c28ba088 100644
--- a/drivers/clk/renesas/rzg2l-cpg.c
+++ b/drivers/clk/renesas/rzg2l-cpg.c
@@ -188,7 +188,8 @@ static int rzg2l_cpg_sd_clk_mux_set_parent(struct clk_hw *hw, u8 index)
 	u32 off = GET_REG_OFFSET(hwdata->conf);
 	u32 shift = GET_SHIFT(hwdata->conf);
 	const u32 clk_src_266 = 2;
-	u32 bitmask;
+	u32 msk, val, bitmask;
+	int ret;
 
 	/*
 	 * As per the HW manual, we should not directly switch from 533 MHz to
@@ -203,9 +204,6 @@ static int rzg2l_cpg_sd_clk_mux_set_parent(struct clk_hw *hw, u8 index)
 	 */
 	bitmask = (GENMASK(GET_WIDTH(hwdata->conf) - 1, 0) << shift) << 16;
 	if (index != clk_src_266) {
-		u32 msk, val;
-		int ret;
-
 		writel(bitmask | ((clk_src_266 + 1) << shift), priv->base + off);
 
 		msk = off ? CPG_CLKSTATUS_SELSDHI1_STS : CPG_CLKSTATUS_SELSDHI0_STS;
@@ -221,7 +219,13 @@ static int rzg2l_cpg_sd_clk_mux_set_parent(struct clk_hw *hw, u8 index)
 
 	writel(bitmask | ((index + 1) << shift), priv->base + off);
 
-	return 0;
+	ret = readl_poll_timeout(priv->base + CPG_CLKSTATUS, val,
+				 !(val & msk), 100,
+				 CPG_SDHI_CLK_SWITCH_STATUS_TIMEOUT_US);
+	if (ret)
+		dev_err(priv->dev, "failed to switch clk source\n");
+
+	return ret;
 }
 
 static u8 rzg2l_cpg_sd_clk_mux_get_parent(struct clk_hw *hw)
-- 
2.39.2