linux-kernel - [PATCH v2 1/9] pinctrl: pinconf-generic: Add property "skew-delay-direction"

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Message-ID: <20250905135547.934729-2-antonio.borneo@foss.st.com>
Date: Fri, 5 Sep 2025 15:55:39 +0200
From: Antonio Borneo <antonio.borneo@...s.st.com>
To: Linus Walleij <linus.walleij@...aro.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue
	<alexandre.torgue@...s.st.com>,
        Bartosz Golaszewski <brgl@...ev.pl>, <linux-gpio@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>
CC: Antonio Borneo <antonio.borneo@...s.st.com>,
        Christophe Roullier
	<christophe.roullier@...s.st.com>,
        Fabien Dessenne
	<fabien.dessenne@...s.st.com>,
        Valentin Caron <valentin.caron@...s.st.com>
Subject: [PATCH v2 1/9] pinctrl: pinconf-generic: Add property "skew-delay-direction"

Add the property "skew-delay-direction" to the generic parameters
used for parsing DT files. This allows to specify the direction
(either input, output or both) on which the existing property
"skew-delay" applies.
For backward compatibility, set default to 0, equivalent to "both
input and output directions".
This enables drivers that use the generic pin configuration to get
the value passed through this new property.

Signed-off-by: Antonio Borneo <antonio.borneo@...s.st.com>
---
 drivers/pinctrl/pinconf-generic.c       | 2 ++
 include/linux/pinctrl/pinconf-generic.h | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/pinctrl/pinconf-generic.c b/drivers/pinctrl/pinconf-generic.c
index d67838afb0857..d2713fce0ab0f 100644
--- a/drivers/pinctrl/pinconf-generic.c
+++ b/drivers/pinctrl/pinconf-generic.c
@@ -54,6 +54,7 @@ static const struct pin_config_item conf_items[] = {
 	PCONFDUMP(PIN_CONFIG_SLEEP_HARDWARE_STATE, "sleep hardware state", NULL, false),
 	PCONFDUMP(PIN_CONFIG_SLEW_RATE, "slew rate", NULL, true),
 	PCONFDUMP(PIN_CONFIG_SKEW_DELAY, "skew delay", NULL, true),
+	PCONFDUMP(PIN_CONFIG_SKEW_DELAY_DIRECTION, "skew delay direction", NULL, true),
 };
 
 static void pinconf_generic_dump_one(struct pinctrl_dev *pctldev,
@@ -190,6 +191,7 @@ static const struct pinconf_generic_params dt_params[] = {
 	{ "sleep-hardware-state", PIN_CONFIG_SLEEP_HARDWARE_STATE, 0 },
 	{ "slew-rate", PIN_CONFIG_SLEW_RATE, 0 },
 	{ "skew-delay", PIN_CONFIG_SKEW_DELAY, 0 },
+	{ "skew-delay-direction", PIN_CONFIG_SKEW_DELAY_DIRECTION, 0 },
 };
 
 /**
diff --git a/include/linux/pinctrl/pinconf-generic.h b/include/linux/pinctrl/pinconf-generic.h
index 1bcf071b860eb..7e49d4e60b9fb 100644
--- a/include/linux/pinctrl/pinconf-generic.h
+++ b/include/linux/pinctrl/pinconf-generic.h
@@ -108,6 +108,11 @@ struct pinctrl_map;
  *	or latch delay (on outputs) this parameter (in a custom format)
  *	specifies the clock skew or latch delay. It typically controls how
  *	many double inverters are put in front of the line.
+ * @PIN_CONFIG_SKEW_DELAY_DIRECTION: this will configure the direction of the
+ *	skew rate or latch delay. If not present or it's 0, latch delay (on
+ *	outputs) and/or skew rate (on inputs) is applied. If it's 1, then only
+ *	latch delay on outputs is applied. If it's 2, then only skew rate on
+ *	inputs is applied.
  * @PIN_CONFIG_SLEEP_HARDWARE_STATE: indicate this is sleep related state.
  * @PIN_CONFIG_SLEW_RATE: if the pin can select slew rate, the argument to
  *	this parameter (on a custom format) tells the driver which alternative
@@ -143,6 +148,7 @@ enum pin_config_param {
 	PIN_CONFIG_PERSIST_STATE,
 	PIN_CONFIG_POWER_SOURCE,
 	PIN_CONFIG_SKEW_DELAY,
+	PIN_CONFIG_SKEW_DELAY_DIRECTION,
 	PIN_CONFIG_SLEEP_HARDWARE_STATE,
 	PIN_CONFIG_SLEW_RATE,
 	PIN_CONFIG_END = 0x7F,
-- 
2.34.1