* [PATCH v2 1/3] gpio: Add GPIO delay driver
2026-02-03 7:52 [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria Michal Simek
@ 2026-02-03 7:52 ` Michal Simek
2026-02-03 7:52 ` [PATCH v2 2/3] xilinx: Enable GPIO delay driver on Kria platforms Michal Simek
` (3 subsequent siblings)
4 siblings, 0 replies; 10+ messages in thread
From: Michal Simek @ 2026-02-03 7:52 UTC (permalink / raw)
To: u-boot, git
Cc: Arturs Artamonovs, Eoin Dickson, Greg Malysa, Ian Roberts,
J. Neuschäfer, Nathan Barrett-Morrison, Neil Armstrong,
Oliver Gaskell, Philip Molloy, Rasmus Villemoes, Tanmay Kathpalia,
Tom Rini, Utsav Agarwal, Vasileios Bimpikas
Add a GPIO controller driver that provides configurable delays when
setting GPIO output values. This is useful for hardware that requires
specific timing delays during power sequencing or GPIO state changes.
The driver wraps underlying GPIO controllers and adds programmable
ramp-up and ramp-down delays specified in microseconds through the
device tree. Each GPIO can have independent delay timings.
Device tree binding matches Linux.
Signed-off-by: Michal Simek <michal.simek@amd.com>
---
Changes in v2:
- Check return value from dm_gpio_set_value()
- Do not use GPIOD_IS_OUT when requesting gpio
drivers/gpio/Kconfig | 8 +++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-delay.c | 139 ++++++++++++++++++++++++++++++++++++++
3 files changed, 148 insertions(+)
create mode 100644 drivers/gpio/gpio-delay.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 60c5c54688e6..f69919abc05b 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1,3 +1,11 @@
+config GPIO_DELAY
+ bool "GPIO delay driver"
+ depends on DM_GPIO
+ help
+ Enable the GPIO delay driver.
+ This driver allows wrapping another GPIO controller and inserting
+ ramp-up/ramp-down delays on output changes, as described in the
+ Linux gpio-delay binding.
#
# GPIO infrastructure and drivers
#
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 910478c0c7a9..fec258f59f52 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_ATMEL_PIO4) += atmel_pio4.o
obj-$(CONFIG_BCM6345_GPIO) += bcm6345_gpio.o
obj-$(CONFIG_CORTINA_GPIO) += cortina_gpio.o
obj-$(CONFIG_FXL6408_GPIO) += gpio-fxl6408.o
+obj-$(CONFIG_GPIO_DELAY) += gpio-delay.o
obj-$(CONFIG_INTEL_GPIO) += intel_gpio.o
obj-$(CONFIG_INTEL_ICH6_GPIO) += intel_ich6_gpio.o
obj-$(CONFIG_INTEL_BROADWELL_GPIO) += intel_broadwell_gpio.o
diff --git a/drivers/gpio/gpio-delay.c b/drivers/gpio/gpio-delay.c
new file mode 100644
index 000000000000..9105deecc4f3
--- /dev/null
+++ b/drivers/gpio/gpio-delay.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025 - 2026, Advanced Micro Devices, Inc.
+ *
+ * Michal Simek <michal.simek@amd.com>
+ */
+
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <dm/devres.h>
+#include <asm/gpio.h>
+#include <linux/delay.h>
+
+struct gpio_delay_desc {
+ struct gpio_desc real_gpio;
+ u32 ramp_up_us;
+ u32 ramp_down_us;
+};
+
+struct gpio_delay_priv {
+ struct gpio_delay_desc *descs;
+};
+
+static int gpio_delay_direction_input(struct udevice *dev, unsigned int offset)
+{
+ return -ENOSYS;
+}
+
+static int gpio_delay_get_value(struct udevice *dev, unsigned int offset)
+{
+ return -ENOSYS;
+}
+
+static int gpio_delay_set_value(struct udevice *dev, unsigned int offset,
+ int value)
+{
+ struct gpio_delay_priv *priv = dev_get_priv(dev);
+ struct gpio_delay_desc *desc = &priv->descs[offset];
+ u32 wait;
+ int ret;
+
+ dev_dbg(dev, "gpio %d set to %d\n", offset, value);
+
+ ret = dm_gpio_set_value(&desc->real_gpio, value);
+ if (ret) {
+ dev_err(dev, "Failed to set gpio %d, value %d\n", offset, value);
+ return ret;
+ }
+
+ if (value)
+ wait = desc->ramp_up_us;
+ else
+ wait = desc->ramp_down_us;
+
+ udelay(wait);
+
+ dev_dbg(dev, "waited for %d us\n", wait);
+
+ return 0;
+}
+
+static int gpio_delay_direction_output(struct udevice *dev, unsigned int offset,
+ int value)
+{
+ return gpio_delay_set_value(dev, offset, value);
+}
+
+static int gpio_delay_xlate(struct udevice *dev, struct gpio_desc *desc,
+ struct ofnode_phandle_args *args)
+{
+ struct gpio_delay_priv *priv = dev_get_priv(dev);
+
+ if (args->args_count < 3)
+ return -EINVAL;
+
+ if (args->args[0] >= 32)
+ return -EINVAL;
+
+ struct gpio_delay_desc *d = &priv->descs[args->args[0]];
+
+ d->ramp_up_us = args->args[1];
+ d->ramp_down_us = args->args[2];
+
+ dev_dbg(dev, "pin: %d, ramp_up_us: %d, ramp_down_us: %d\n",
+ args->args[0], d->ramp_up_us, d->ramp_down_us);
+
+ return 0;
+}
+
+static const struct dm_gpio_ops gpio_delay_ops = {
+ .direction_output = gpio_delay_direction_output,
+ .direction_input = gpio_delay_direction_input,
+ .get_value = gpio_delay_get_value,
+ .set_value = gpio_delay_set_value,
+ .xlate = gpio_delay_xlate,
+};
+
+static int gpio_delay_probe(struct udevice *dev)
+{
+ struct gpio_delay_priv *priv = dev_get_priv(dev);
+ struct gpio_delay_desc *d;
+ ofnode node = dev_ofnode(dev);
+ int i = 0, ret, ngpio;
+
+ ngpio = gpio_get_list_count(dev, "gpios");
+ if (ngpio < 0)
+ return ngpio;
+
+ dev_dbg(dev, "gpios: %d\n", ngpio);
+
+ priv->descs = devm_kmalloc_array(dev, ngpio, sizeof(*d), GFP_KERNEL);
+ if (!priv->descs)
+ return -ENOMEM;
+
+ /* Request all GPIOs described in the controller node */
+ for (i = 0; i < ngpio; i++) {
+ d = &priv->descs[i];
+ ret = gpio_request_by_name_nodev(node, "gpios", i,
+ &d->real_gpio, 0);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct udevice_id gpio_delay_ids[] = {
+ { .compatible = "gpio-delay" },
+ { }
+};
+
+U_BOOT_DRIVER(gpio_delay) = {
+ .name = "gpio-delay",
+ .id = UCLASS_GPIO,
+ .of_match = gpio_delay_ids,
+ .ops = &gpio_delay_ops,
+ .priv_auto = sizeof(struct gpio_delay_priv),
+ .probe = gpio_delay_probe,
+};
--
2.43.0
^ permalink raw reply related [flat|nested] 10+ messages in thread* [PATCH v2 2/3] xilinx: Enable GPIO delay driver on Kria platforms
2026-02-03 7:52 [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria Michal Simek
2026-02-03 7:52 ` [PATCH v2 1/3] gpio: Add GPIO delay driver Michal Simek
@ 2026-02-03 7:52 ` Michal Simek
2026-02-03 7:52 ` [PATCH v2 3/3] arm64: zynqmp: Wire gpio-delay driver for USB hub reset Michal Simek
` (2 subsequent siblings)
4 siblings, 0 replies; 10+ messages in thread
From: Michal Simek @ 2026-02-03 7:52 UTC (permalink / raw)
To: u-boot, git
Cc: Anshul Dalal, Fabio Estevam, Ilias Apalodimas, Marek Vasut,
Simon Glass, Tom Rini
GPIO delay driver is necessary to use to extend delay times for USB hubs
available on the Kria platforms.
Signed-off-by: Michal Simek <michal.simek@amd.com>
---
(no changes since v1)
configs/xilinx_zynqmp_kria_defconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/configs/xilinx_zynqmp_kria_defconfig b/configs/xilinx_zynqmp_kria_defconfig
index 8ad05e371892..1e0728fa4f3f 100644
--- a/configs/xilinx_zynqmp_kria_defconfig
+++ b/configs/xilinx_zynqmp_kria_defconfig
@@ -136,6 +136,7 @@ CONFIG_XILINX_DPDMA=y
CONFIG_ARM_FFA_TRANSPORT=y
CONFIG_FPGA_XILINX=y
CONFIG_FPGA_ZYNQMPPL=y
+CONFIG_GPIO_DELAY=y
CONFIG_GPIO_HOG=y
CONFIG_XILINX_GPIO=y
CONFIG_DM_PCA953X=y
--
2.43.0
^ permalink raw reply related [flat|nested] 10+ messages in thread* [PATCH v2 3/3] arm64: zynqmp: Wire gpio-delay driver for USB hub reset
2026-02-03 7:52 [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria Michal Simek
2026-02-03 7:52 ` [PATCH v2 1/3] gpio: Add GPIO delay driver Michal Simek
2026-02-03 7:52 ` [PATCH v2 2/3] xilinx: Enable GPIO delay driver on Kria platforms Michal Simek
@ 2026-02-03 7:52 ` Michal Simek
2026-02-03 11:39 ` [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria Marek Vasut
2026-02-12 11:33 ` Michal Simek
4 siblings, 0 replies; 10+ messages in thread
From: Michal Simek @ 2026-02-03 7:52 UTC (permalink / raw)
To: u-boot, git
Cc: Radhey Shyam Pandey, Nithish Kumar Naroju, Rohit Visavalia,
Tom Rini
USB hub requires longer delay to get out of the reset to work properly
that's why use gpio-delay to ensure enough waiting time.
Signed-off-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
---
Changes in v2:
- fix commit message
arch/arm/dts/zynqmp-sck-kd-g-revA.dtso | 13 ++++++++++---
arch/arm/dts/zynqmp-sck-kr-g-revA.dtso | 16 ++++++++++++----
arch/arm/dts/zynqmp-sck-kr-g-revB.dtso | 16 ++++++++++++----
arch/arm/dts/zynqmp-sck-kv-g-revA.dtso | 13 ++++++++++---
arch/arm/dts/zynqmp-sck-kv-g-revB.dtso | 11 +++++++++--
5 files changed, 53 insertions(+), 16 deletions(-)
diff --git a/arch/arm/dts/zynqmp-sck-kd-g-revA.dtso b/arch/arm/dts/zynqmp-sck-kd-g-revA.dtso
index 832dc5ab2458..8342479b108a 100644
--- a/arch/arm/dts/zynqmp-sck-kd-g-revA.dtso
+++ b/arch/arm/dts/zynqmp-sck-kd-g-revA.dtso
@@ -3,7 +3,7 @@
* dts file for KD240 revA Carrier Card
*
* Copyright (C) 2021 - 2022, Xilinx, Inc.
- * Copyright (C) 2022 - 2023, Advanced Micro Devices, Inc.
+ * Copyright (C) 2022 - 2026, Advanced Micro Devices, Inc.
*
* Michal Simek <michal.simek@amd.com>
*/
@@ -43,6 +43,13 @@
#clock-cells = <0>;
clock-frequency = <25000000>;
};
+
+ slg_delay: enable-delay {
+ compatible = "gpio-delay";
+ #gpio-cells = <3>;
+ gpio-controller;
+ gpios = <&slg7xl45106 3 GPIO_ACTIVE_LOW>;
+ };
};
&can0 {
@@ -116,7 +123,7 @@
reg = <1>;
peer-hub = <&hub_3_0>;
i2c-bus = <&hub>;
- reset-gpios = <&slg7xl45106 3 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 0 10000 10000>;
};
/* 3.0 hub on port 2 */
@@ -125,7 +132,7 @@
reg = <2>;
peer-hub = <&hub_2_0>;
i2c-bus = <&hub>;
- reset-gpios = <&slg7xl45106 3 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 0 10000 10000>;
};
};
diff --git a/arch/arm/dts/zynqmp-sck-kr-g-revA.dtso b/arch/arm/dts/zynqmp-sck-kr-g-revA.dtso
index 532f6bf92bc5..db042ffb4f36 100644
--- a/arch/arm/dts/zynqmp-sck-kr-g-revA.dtso
+++ b/arch/arm/dts/zynqmp-sck-kr-g-revA.dtso
@@ -77,6 +77,14 @@
};
};
};
+
+ slg_delay: enable-delay {
+ compatible = "gpio-delay";
+ #gpio-cells = <3>;
+ gpio-controller;
+ gpios = <&slg7xl45106 3 GPIO_ACTIVE_LOW>,
+ <&slg7xl45106 4 GPIO_ACTIVE_LOW>;
+ };
};
&i2c1 { /* I2C_SCK C26/C27 - MIO from SOM */
@@ -187,7 +195,7 @@
reg = <1>;
peer-hub = <&hub_3_0>;
i2c-bus = <&hub_1>;
- reset-gpios = <&slg7xl45106 3 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 0 10000 10000>;
};
/* 3.0 hub on port 2 */
@@ -196,7 +204,7 @@
reg = <2>;
peer-hub = <&hub_2_0>;
i2c-bus = <&hub_1>;
- reset-gpios = <&slg7xl45106 3 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 0 10000 10000>;
};
};
@@ -224,7 +232,7 @@
reg = <1>;
peer-hub = <&hub1_3_0>;
i2c-bus = <&hub_2>;
- reset-gpios = <&slg7xl45106 4 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 1 10000 10000>;
};
/* 3.0 hub on port 2 */
@@ -233,7 +241,7 @@
reg = <2>;
peer-hub = <&hub1_2_0>;
i2c-bus = <&hub_2>;
- reset-gpios = <&slg7xl45106 4 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 1 10000 10000>;
};
};
diff --git a/arch/arm/dts/zynqmp-sck-kr-g-revB.dtso b/arch/arm/dts/zynqmp-sck-kr-g-revB.dtso
index 458d79e81192..e3567d0abfe0 100644
--- a/arch/arm/dts/zynqmp-sck-kr-g-revB.dtso
+++ b/arch/arm/dts/zynqmp-sck-kr-g-revB.dtso
@@ -78,6 +78,14 @@
};
};
};
+
+ slg_delay: enable-delay {
+ compatible = "gpio-delay";
+ #gpio-cells = <3>;
+ gpio-controller;
+ gpios = <&slg7xl45106 3 GPIO_ACTIVE_LOW>,
+ <&slg7xl45106 4 GPIO_ACTIVE_LOW>;
+ };
};
&i2c1 { /* I2C_SCK C26/C27 - MIO from SOM */
@@ -188,7 +196,7 @@
reg = <1>;
peer-hub = <&hub_3_0>;
i2c-bus = <&hub_1>;
- reset-gpios = <&slg7xl45106 3 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 0 10000 10000>;
};
/* 3.0 hub on port 2 */
@@ -197,7 +205,7 @@
reg = <2>;
peer-hub = <&hub_2_0>;
i2c-bus = <&hub_1>;
- reset-gpios = <&slg7xl45106 3 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 0 10000 10000>;
};
};
@@ -225,7 +233,7 @@
reg = <1>;
peer-hub = <&hub1_3_0>;
i2c-bus = <&hub_2>;
- reset-gpios = <&slg7xl45106 4 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 1 10000 10000>;
};
/* 3.0 hub on port 2 */
@@ -234,7 +242,7 @@
reg = <2>;
peer-hub = <&hub1_2_0>;
i2c-bus = <&hub_2>;
- reset-gpios = <&slg7xl45106 4 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 1 10000 10000>;
};
};
diff --git a/arch/arm/dts/zynqmp-sck-kv-g-revA.dtso b/arch/arm/dts/zynqmp-sck-kv-g-revA.dtso
index e7417af8ae01..f93c7460a552 100644
--- a/arch/arm/dts/zynqmp-sck-kv-g-revA.dtso
+++ b/arch/arm/dts/zynqmp-sck-kv-g-revA.dtso
@@ -3,7 +3,7 @@
* dts file for KV260 revA Carrier Card
*
* (C) Copyright 2020 - 2022, Xilinx, Inc.
- * (C) Copyright 2022 - 2025, Advanced Micro Devices, Inc.
+ * (C) Copyright 2022 - 2026, Advanced Micro Devices, Inc.
*
* SD level shifter:
* "A" - A01 board un-modified (NXP)
@@ -78,6 +78,13 @@
};
};
};
+
+ slg_delay: enable-delay {
+ compatible = "gpio-delay";
+ #gpio-cells = <3>;
+ gpio-controller;
+ gpios = <&gpio 44 GPIO_ACTIVE_LOW>;
+ };
};
&i2c1 { /* I2C_SCK C23/C24 - MIO from SOM */
@@ -161,7 +168,7 @@
compatible = "usb424,2744";
reg = <1>;
peer-hub = <&hub_3_0>;
- reset-gpios = <&gpio 44 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 0 10000 10000>;
};
/* 3.0 hub on port 2 */
@@ -169,7 +176,7 @@
compatible = "usb424,5744";
reg = <2>;
peer-hub = <&hub_2_0>;
- reset-gpios = <&gpio 44 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 0 10000 10000>;
};
};
diff --git a/arch/arm/dts/zynqmp-sck-kv-g-revB.dtso b/arch/arm/dts/zynqmp-sck-kv-g-revB.dtso
index 7a05180e58b4..70de6933600e 100644
--- a/arch/arm/dts/zynqmp-sck-kv-g-revB.dtso
+++ b/arch/arm/dts/zynqmp-sck-kv-g-revB.dtso
@@ -74,6 +74,13 @@
};
};
};
+
+ slg_delay: enable-delay {
+ compatible = "gpio-delay";
+ #gpio-cells = <3>;
+ gpio-controller;
+ gpios = <&gpio 44 GPIO_ACTIVE_LOW>;
+ };
};
&i2c1 { /* I2C_SCK C23/C24 - MIO from SOM */
@@ -148,7 +155,7 @@
reg = <1>;
peer-hub = <&hub_3_0>;
i2c-bus = <&hub>;
- reset-gpios = <&gpio 44 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 0 10000 10000>;
};
/* 3.0 hub on port 2 */
@@ -157,7 +164,7 @@
reg = <2>;
peer-hub = <&hub_2_0>;
i2c-bus = <&hub>;
- reset-gpios = <&gpio 44 GPIO_ACTIVE_LOW>;
+ reset-gpios = <&slg_delay 0 10000 10000>;
};
};
--
2.43.0
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria
2026-02-03 7:52 [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria Michal Simek
` (2 preceding siblings ...)
2026-02-03 7:52 ` [PATCH v2 3/3] arm64: zynqmp: Wire gpio-delay driver for USB hub reset Michal Simek
@ 2026-02-03 11:39 ` Marek Vasut
2026-02-03 15:32 ` Michal Simek
2026-02-12 11:33 ` Michal Simek
4 siblings, 1 reply; 10+ messages in thread
From: Marek Vasut @ 2026-02-03 11:39 UTC (permalink / raw)
To: Michal Simek, u-boot, git
Cc: Anshul Dalal, Arturs Artamonovs, Eoin Dickson, Fabio Estevam,
Greg Malysa, Ian Roberts, Ilias Apalodimas, J. Neuschäfer,
Marek Vasut, Nathan Barrett-Morrison, Neil Armstrong,
Nithish Kumar Naroju, Oliver Gaskell, Philip Molloy,
Radhey Shyam Pandey, Rasmus Villemoes, Rohit Visavalia,
Simon Glass, Tanmay Kathpalia, Tom Rini, Utsav Agarwal,
Vasileios Bimpikas
On 2/3/26 8:52 AM, Michal Simek wrote:
> Hi,
>
> we need to wait more time for getting USB hub out of reset to be able to do
> initialiation over i2c that's why use gpio-delay driver instead of changing
> waiting time in usb hub driver. Waiting time depends on gpio wiring on the
> board which is in some of our case going via SLG programmable device.
Can you not use some regulator or make the reset assert/deassert time
configurable via DT property ?
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria
2026-02-03 11:39 ` [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria Marek Vasut
@ 2026-02-03 15:32 ` Michal Simek
2026-02-03 16:38 ` Marek Vasut
0 siblings, 1 reply; 10+ messages in thread
From: Michal Simek @ 2026-02-03 15:32 UTC (permalink / raw)
To: Marek Vasut, u-boot, git
Cc: Anshul Dalal, Arturs Artamonovs, Eoin Dickson, Fabio Estevam,
Greg Malysa, Ian Roberts, Ilias Apalodimas, J. Neuschäfer,
Marek Vasut, Nathan Barrett-Morrison, Neil Armstrong,
Nithish Kumar Naroju, Oliver Gaskell, Philip Molloy,
Radhey Shyam Pandey, Rasmus Villemoes, Rohit Visavalia,
Simon Glass, Tanmay Kathpalia, Tom Rini, Utsav Agarwal,
Vasileios Bimpikas
On 2/3/26 12:39, Marek Vasut wrote:
> On 2/3/26 8:52 AM, Michal Simek wrote:
>> Hi,
>>
>> we need to wait more time for getting USB hub out of reset to be able to do
>> initialiation over i2c that's why use gpio-delay driver instead of changing
>> waiting time in usb hub driver. Waiting time depends on gpio wiring on the
>> board which is in some of our case going via SLG programmable device.
> Can you not use some regulator or make the reset assert/deassert time
> configurable via DT property ?
Sorry not following. delay is configurable via DT now - the patch 3/3 for example.
This avoid a need to change usb5744 driver to wait longer time which is what we
discussed in past.
M
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria
2026-02-03 15:32 ` Michal Simek
@ 2026-02-03 16:38 ` Marek Vasut
2026-02-03 16:57 ` Quentin Schulz
0 siblings, 1 reply; 10+ messages in thread
From: Marek Vasut @ 2026-02-03 16:38 UTC (permalink / raw)
To: Michal Simek, u-boot, git
Cc: Anshul Dalal, Arturs Artamonovs, Eoin Dickson, Fabio Estevam,
Greg Malysa, Ian Roberts, Ilias Apalodimas, J. Neuschäfer,
Nathan Barrett-Morrison, Neil Armstrong, Nithish Kumar Naroju,
Oliver Gaskell, Philip Molloy, Radhey Shyam Pandey,
Rasmus Villemoes, Rohit Visavalia, Simon Glass, Tanmay Kathpalia,
Tom Rini, Utsav Agarwal, Vasileios Bimpikas
On 2/3/26 4:32 PM, Michal Simek wrote:
>
>
> On 2/3/26 12:39, Marek Vasut wrote:
>> On 2/3/26 8:52 AM, Michal Simek wrote:
>>> Hi,
>>>
>>> we need to wait more time for getting USB hub out of reset to be able
>>> to do
>>> initialiation over i2c that's why use gpio-delay driver instead of
>>> changing
>>> waiting time in usb hub driver. Waiting time depends on gpio wiring
>>> on the
>>> board which is in some of our case going via SLG programmable device.
>> Can you not use some regulator or make the reset assert/deassert time
>> configurable via DT property ?
>
> Sorry not following. delay is configurable via DT now - the patch 3/3
> for example.
3/3 never arrived in my mailbox, I think I was CCed only on 0 and 2 .
> This avoid a need to change usb5744 driver to wait longer time which is
> what we discussed in past.
If the delay is configurable via DT, why would the driver have to be
changed ?
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria
2026-02-03 16:38 ` Marek Vasut
@ 2026-02-03 16:57 ` Quentin Schulz
2026-02-03 20:42 ` Marek Vasut
0 siblings, 1 reply; 10+ messages in thread
From: Quentin Schulz @ 2026-02-03 16:57 UTC (permalink / raw)
To: Marek Vasut, Michal Simek, u-boot, git
Cc: Anshul Dalal, Arturs Artamonovs, Eoin Dickson, Fabio Estevam,
Greg Malysa, Ian Roberts, Ilias Apalodimas, J. Neuschäfer,
Nathan Barrett-Morrison, Neil Armstrong, Nithish Kumar Naroju,
Oliver Gaskell, Philip Molloy, Radhey Shyam Pandey,
Rasmus Villemoes, Rohit Visavalia, Simon Glass, Tanmay Kathpalia,
Tom Rini, Utsav Agarwal, Vasileios Bimpikas
Hi Marek,
On 2/3/26 5:38 PM, Marek Vasut wrote:
> On 2/3/26 4:32 PM, Michal Simek wrote:
>>
>>
>> On 2/3/26 12:39, Marek Vasut wrote:
>>> On 2/3/26 8:52 AM, Michal Simek wrote:
>>>> Hi,
>>>>
>>>> we need to wait more time for getting USB hub out of reset to be
>>>> able to do
>>>> initialiation over i2c that's why use gpio-delay driver instead of
>>>> changing
>>>> waiting time in usb hub driver. Waiting time depends on gpio wiring
>>>> on the
>>>> board which is in some of our case going via SLG programmable device.
>>> Can you not use some regulator or make the reset assert/deassert time
>>> configurable via DT property ?
>>
>> Sorry not following. delay is configurable via DT now - the patch 3/3
>> for example.
>
> 3/3 never arrived in my mailbox, I think I was CCed only on 0 and 2 .
>
>> This avoid a need to change usb5744 driver to wait longer time which
>> is what we discussed in past.
> If the delay is configurable via DT, why would the driver have to be
> changed ?
Delay is configurable via DT for the GPIO delay device. The delay is NOT
configurable via DT for the USB onboard hub device. Because of the
latter, the former is added as GPIO controller for adding delay to the
latter driver's reset line.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria
2026-02-03 16:57 ` Quentin Schulz
@ 2026-02-03 20:42 ` Marek Vasut
0 siblings, 0 replies; 10+ messages in thread
From: Marek Vasut @ 2026-02-03 20:42 UTC (permalink / raw)
To: Quentin Schulz, Michal Simek, u-boot, git
Cc: Anshul Dalal, Arturs Artamonovs, Eoin Dickson, Fabio Estevam,
Greg Malysa, Ian Roberts, Ilias Apalodimas, J. Neuschäfer,
Nathan Barrett-Morrison, Neil Armstrong, Nithish Kumar Naroju,
Oliver Gaskell, Philip Molloy, Radhey Shyam Pandey,
Rasmus Villemoes, Rohit Visavalia, Simon Glass, Tanmay Kathpalia,
Tom Rini, Utsav Agarwal, Vasileios Bimpikas
On 2/3/26 5:57 PM, Quentin Schulz wrote:
> Hi Marek,
>
> On 2/3/26 5:38 PM, Marek Vasut wrote:
>> On 2/3/26 4:32 PM, Michal Simek wrote:
>>>
>>>
>>> On 2/3/26 12:39, Marek Vasut wrote:
>>>> On 2/3/26 8:52 AM, Michal Simek wrote:
>>>>> Hi,
>>>>>
>>>>> we need to wait more time for getting USB hub out of reset to be
>>>>> able to do
>>>>> initialiation over i2c that's why use gpio-delay driver instead of
>>>>> changing
>>>>> waiting time in usb hub driver. Waiting time depends on gpio wiring
>>>>> on the
>>>>> board which is in some of our case going via SLG programmable device.
>>>> Can you not use some regulator or make the reset assert/deassert
>>>> time configurable via DT property ?
>>>
>>> Sorry not following. delay is configurable via DT now - the patch 3/3
>>> for example.
>>
>> 3/3 never arrived in my mailbox, I think I was CCed only on 0 and 2 .
>>
>>> This avoid a need to change usb5744 driver to wait longer time which
>>> is what we discussed in past.
>> If the delay is configurable via DT, why would the driver have to be
>> changed ?
>
> Delay is configurable via DT for the GPIO delay device. The delay is NOT
> configurable via DT for the USB onboard hub device. Because of the
> latter, the former is added as GPIO controller for adding delay to the
> latter driver's reset line.
Oh, I see, thank you for the clarification.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria
2026-02-03 7:52 [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria Michal Simek
` (3 preceding siblings ...)
2026-02-03 11:39 ` [PATCH v2 0/3] gpio: Introduce gpio-delay driver and enable it on Kria Marek Vasut
@ 2026-02-12 11:33 ` Michal Simek
4 siblings, 0 replies; 10+ messages in thread
From: Michal Simek @ 2026-02-12 11:33 UTC (permalink / raw)
To: u-boot, git
Cc: Anshul Dalal, Arturs Artamonovs, Eoin Dickson, Fabio Estevam,
Greg Malysa, Ian Roberts, Ilias Apalodimas, J. Neuschäfer,
Marek Vasut, Nathan Barrett-Morrison, Neil Armstrong,
Nithish Kumar Naroju, Oliver Gaskell, Philip Molloy,
Radhey Shyam Pandey, Rasmus Villemoes, Rohit Visavalia,
Simon Glass, Tanmay Kathpalia, Tom Rini, Utsav Agarwal,
Vasileios Bimpikas
On 2/3/26 08:52, Michal Simek wrote:
> Hi,
>
> we need to wait more time for getting USB hub out of reset to be able to do
> initialiation over i2c that's why use gpio-delay driver instead of changing
> waiting time in usb hub driver. Waiting time depends on gpio wiring on the
> board which is in some of our case going via SLG programmable device.
>
> Thanks,
> Michal
>
> Changes in v2:
> - Check return value from dm_gpio_set_value()
> - Do not use GPIOD_IS_OUT when requesting gpio
> - fix commit message
>
> Michal Simek (3):
> gpio: Add GPIO delay driver
> xilinx: Enable GPIO delay driver on Kria platforms
> arm64: zynqmp: Wire gpio-delay driver for USB hub reset
>
> arch/arm/dts/zynqmp-sck-kd-g-revA.dtso | 13 ++-
> arch/arm/dts/zynqmp-sck-kr-g-revA.dtso | 16 ++-
> arch/arm/dts/zynqmp-sck-kr-g-revB.dtso | 16 ++-
> arch/arm/dts/zynqmp-sck-kv-g-revA.dtso | 13 ++-
> arch/arm/dts/zynqmp-sck-kv-g-revB.dtso | 11 +-
> configs/xilinx_zynqmp_kria_defconfig | 1 +
> drivers/gpio/Kconfig | 8 ++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-delay.c | 139 +++++++++++++++++++++++++
> 9 files changed, 202 insertions(+), 16 deletions(-)
> create mode 100644 drivers/gpio/gpio-delay.c
>
Applied.
M
^ permalink raw reply [flat|nested] 10+ messages in thread