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From: Mike Looijmans <mike.looijmans@topic.nl>
To: lars@metafoo.de
Cc: Peter.Chen@freescale.com, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Mike Looijmans <mike.looijmans@topic.nl>
Subject: [PATCH 1/2] usb: chipidea: Reduce ULPI PHY reset pulse to datasheet spec of 1us
Date: Fri, 26 Jun 2015 15:47:03 +0200	[thread overview]
Message-ID: <1435326424-18748-1-git-send-email-mike.looijmans@topic.nl> (raw)

The datasheet for the 334x PHY mentions that a reset can be performed:
"... by bringing the pin low for a minimum of 1 microsecond and
then high."
A delay of 5ms to implement that seems overly long, so reduce it to
just 1us.
As for the delay after reset, the datasheet only mentioned that the
chip will assert the DIR output. 1ms seems like a safe time to wait
for that to happen, so no change there.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
---
 drivers/usb/chipidea/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index e970863..c865abe 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -664,7 +664,7 @@ static int ci_hdrc_create_ulpi_phy(struct device *dev, struct ci_hdrc *ci)
 			dev_err(dev, "Failed to request ULPI reset gpio: %d\n", ret);
 			return ret;
 		}
-		msleep(5);
+		udelay(1);
 		gpio_set_value_cansleep(reset_gpio, 1);
 		msleep(1);
 	}
-- 
1.9.1


             reply	other threads:[~2015-06-26 13:47 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-26 13:47 Mike Looijmans [this message]
2015-06-26 13:47 ` [PATCH 2/2] usb: chipidea: Wait 50 ms before reading ID bit Mike Looijmans
2015-06-30  2:11   ` Peter Chen
2015-06-30  2:06 ` [PATCH 1/2] usb: chipidea: Reduce ULPI PHY reset pulse to datasheet spec of 1us Peter Chen
2015-07-02  9:39   ` David Laight
2015-07-06 12:54     ` Mike Looijmans

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