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 2/4] dt-bindings: mmc: spacemit,sdhci: Add tx delay property
Date: Wed, 02 Sep 2026 07:03:13 +0000 [thread overview]
Message-ID: <20260902-07-k3-sdhci-dts-v1-2-4e7909cf4233@kernel.org> (raw)
In-Reply-To: <20260902-07-k3-sdhci-dts-v1-0-4e7909cf4233@kernel.org>
From: Long Wan <long.wan@linux.spacemit.com>
Introduce a vendor specific property to configure the step count of TX
delay line which should be applied before RX tuning, compensating for
board level trace differences. The TX delay line result comes from test
out of real board which vary from different hardware layout.
Signed-off-by: Long Wan <long.wan@linux.spacemit.com>
Signed-off-by: Yixun Lan <dlan@kernel.org>
---
Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
index f35bf7ce08dd..3399a2d076dc 100644
--- a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
+++ b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
@@ -63,6 +63,16 @@ properties:
pinctrl-1:
description: Optional pinctrl state for 1.8V UHS operation with "uhs" name
+ spacemit,tx-delay:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 0
+ maximum: 255
+ description:
+ TX delay line setting applied before RX tuning, compensating for
+ board level trace differences. This is a delay line step count with
+ no fixed time-per-step conversion; determined empirically per board
+ specific, used on SD/SDIO hosts.
+
required:
- compatible
- reg
--
2.55.0
next prev parent reply other threads:[~2026-09-02 7:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-02 7:03 [PATCH 0/4] mmc: spacemit: Introduce two DT properties Yixun Lan
2026-09-02 7:03 ` [PATCH 1/4] dt-bindings: mmc: spacemit-sdhci: Add clock-frequency property Yixun Lan
2026-09-02 7:11 ` sashiko-bot
2026-09-02 9:08 ` Yixun Lan
2026-09-02 7:03 ` Yixun Lan [this message]
2026-09-02 7:03 ` [PATCH 3/4] mmc: sdhci-of-k1: Set clock-frequency of io clock Yixun Lan
2026-09-02 7:14 ` sashiko-bot
2026-09-02 7:03 ` [PATCH 4/4] mmc: sdhci-of-k1: Add TX tuning parameter Yixun Lan
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