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From: Mike Looijmans <mike.looijmans@topic.nl>
To: linux-usb@vger.kernel.org
Cc: Mike Looijmans <mike.looijmans@topic.nl>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Michal Simek <michal.simek@amd.com>,
	Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH] usb: dwc3: xilinx: Prevent spike in reset signal
Date: Fri, 14 Mar 2025 16:56:07 +0100	[thread overview]
Message-ID: <20250314155706.31058-1-mike.looijmans@topic.nl> (raw)
In-Reply-To: 1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.323aeebd-1577-4c21-85a6-ff9262fb6cb7@emailsignatures365.codetwo.com

Set the gpio to "high" on acquisition, instead of acquiring it in low
state and then immediately setting it high again. This prevents a
short "spike" on the reset signal.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
---

 drivers/usb/dwc3/dwc3-xilinx.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-xilinx.c b/drivers/usb/dwc3/dwc3-xilinx.c
index a33a42ba0249..a159a511483b 100644
--- a/drivers/usb/dwc3/dwc3-xilinx.c
+++ b/drivers/usb/dwc3/dwc3-xilinx.c
@@ -207,7 +207,7 @@ static int dwc3_xlnx_init_zynqmp(struct dwc3_xlnx *priv_data)
 
 skip_usb3_phy:
 	/* ulpi reset via gpio-modepin or gpio-framework driver */
-	reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(reset_gpio)) {
 		return dev_err_probe(dev, PTR_ERR(reset_gpio),
 				     "Failed to request reset GPIO\n");
@@ -215,7 +215,6 @@ static int dwc3_xlnx_init_zynqmp(struct dwc3_xlnx *priv_data)
 
 	if (reset_gpio) {
 		/* Toggle ulpi to reset the phy. */
-		gpiod_set_value_cansleep(reset_gpio, 1);
 		usleep_range(5000, 10000);
 		gpiod_set_value_cansleep(reset_gpio, 0);
 		usleep_range(5000, 10000);
-- 
2.43.0


Met vriendelijke groet / kind regards,

Mike Looijmans
System Expert


TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands

T: +31 (0) 499 33 69 69
E: mike.looijmans@topic.nl
W: www.topic.nl

Please consider the environment before printing this e-mail

       reply	other threads:[~2025-03-14 15:57 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.323aeebd-1577-4c21-85a6-ff9262fb6cb7@emailsignatures365.codetwo.com>
2025-03-14 15:56 ` Mike Looijmans [this message]
2025-03-14 21:14   ` [PATCH] usb: dwc3: xilinx: Prevent spike in reset signal Thinh Nguyen
2025-03-17  6:21     ` Mike Looijmans
2025-03-18  0:12       ` Thinh Nguyen
2025-03-18  6:21         ` Mike Looijmans
2025-03-18  7:36           ` Michal Simek
2025-03-21 21:24           ` Thinh Nguyen

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