[PATCH 4/4] mmc: sdhci-of-k1: Add TX tuning parameter

From: Yixun Lan <dlan@kernel.org>
To: Ulf Hansson <ulfh@kernel.org>, Rob Herring <robh@kernel.org>,
	 Krzysztof Kozlowski <krzk+dt@kernel.org>,
	 Conor Dooley <conor+dt@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>
Cc: Long Wan <long.wan@linux.spacemit.com>,
	linux-mmc@vger.kernel.org,  devicetree@vger.kernel.org,
	linux-riscv@lists.infradead.org,  spacemit@lists.linux.dev,
	linux-kernel@vger.kernel.org,  Yixun Lan <dlan@kernel.org>
Subject: [PATCH 4/4] mmc: sdhci-of-k1: Add TX tuning parameter
Date: Wed, 02 Sep 2026 07:03:15 +0000	[thread overview]
Message-ID: <20260902-07-k3-sdhci-dts-v1-4-4e7909cf4233@kernel.org> (raw)
In-Reply-To: <20260902-07-k3-sdhci-dts-v1-0-4e7909cf4233@kernel.org>

From: Long Wan <long.wan@linux.spacemit.com>

Instead of setting the TX delay code via hardcoded parameter, configuring
it via device tree property, which make it able to adapt according to
board specific tuning requirement.

Signed-off-by: Long Wan <long.wan@linux.spacemit.com>
Signed-off-by: Yixun Lan <dlan@kernel.org>
---
 drivers/mmc/host/sdhci-of-k1.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
index e6ab40c9a555..6cab06332747 100644
--- a/drivers/mmc/host/sdhci-of-k1.c
+++ b/drivers/mmc/host/sdhci-of-k1.c
@@ -97,6 +97,7 @@ struct spacemit_sdhci_host {
 	struct pinctrl *pinctrl;
 	struct pinctrl_state *pinctrl_default;
 	struct pinctrl_state *pinctrl_uhs;
+	u8 tx_delaycode;
 };
 
 /* All helper functions will update clr/set while preserve rest bits */
@@ -263,6 +264,7 @@ static int spacemit_sdhci_execute_tuning(struct sdhci_host *host, u32 opcode)
 	int max_pass_len = 0, max_pass_start = 0;
 	struct mmc_host *mmc = host->mmc;
 	struct mmc_ios ios = mmc->ios;
+	struct spacemit_sdhci_host *sdhst = sdhci_pltfm_priv(sdhci_priv(host));
 	u8 final_delay;
 	int ret = 0;
 	int i;
@@ -279,11 +281,11 @@ static int spacemit_sdhci_execute_tuning(struct sdhci_host *host, u32 opcode)
 
 	if (mmc->caps2 & MMC_CAP2_NO_MMC) {
 		spacemit_sdhci_set_tx_dline_reg(host, SPACEMIT_TX_TUNING_DLINE_REG);
-		spacemit_sdhci_set_tx_delay(host, SPACEMIT_TX_TUNING_DELAYCODE);
+		spacemit_sdhci_set_tx_delay(host, sdhst->tx_delaycode);
 		spacemit_sdhci_tx_tuning_prepare(host);
 
 		dev_dbg(mmc_dev(host->mmc), "TX tuning: dline_reg=%d, delaycode=%d\n",
-			SPACEMIT_TX_TUNING_DLINE_REG, SPACEMIT_TX_TUNING_DELAYCODE);
+			SPACEMIT_TX_TUNING_DLINE_REG, sdhst->tx_delaycode);
 	}
 
 	spacemit_sdhci_prepare_tuning(host);
@@ -496,6 +498,23 @@ static inline void spacemit_sdhci_get_pins(struct device *dev,
 		sdhst->pinctrl_default, sdhst->pinctrl_uhs);
 }
 
+static void spacemit_sdhci_get_tuning_params(struct device *dev,
+					     struct sdhci_pltfm_host *pltfm_host)
+{
+	struct spacemit_sdhci_host *sdhst = sdhci_pltfm_priv(pltfm_host);
+	u32 val;
+
+	sdhst->tx_delaycode = SPACEMIT_TX_TUNING_DELAYCODE;
+
+	/* Override from DT property */
+	if (!device_property_read_u32(dev, "spacemit,tx-delay", &val)) {
+		if (val <= U8_MAX)
+			sdhst->tx_delaycode = val;
+		else
+			dev_warn(dev, "ignoring invalid tx delay: %u\n", val);
+	}
+}
+
 static const struct sdhci_ops spacemit_sdhci_ops = {
 	.get_max_clock		= spacemit_sdhci_clk_get_max_clock,
 	.reset			= spacemit_sdhci_reset,
@@ -571,6 +590,8 @@ static int spacemit_sdhci_probe(struct platform_device *pdev)
 
 	spacemit_sdhci_get_pins(dev, pltfm_host);
 
+	spacemit_sdhci_get_tuning_params(dev, pltfm_host);
+
 	host->mmc_host_ops.start_signal_voltage_switch = spacemit_sdhci_start_signal_voltage_switch;
 
 	ret = spacemit_sdhci_get_clocks(dev, pltfm_host);

-- 
2.55.0


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
