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Message-Id: <20230725142343.1724130-10-hugo@hugovil.com>
Date: Tue, 25 Jul 2023 10:23:41 -0400
From: Hugo Villeneuve <hugo@...ovil.com>
To: gregkh@...uxfoundation.org, robh+dt@...nel.org,
krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
jirislaby@...nel.org, jringle@...dpoint.com,
isaac.true@...onical.com, jesse.sung@...onical.com,
l.perczak@...lintechnologies.com, tomasz.mon@...lingroup.com
Cc: linux-serial@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, hugo@...ovil.com,
linux-gpio@...r.kernel.org,
Hugo Villeneuve <hvilleneuve@...onoff.com>,
Lech Perczak <lech.perczak@...lingroup.com>
Subject: [PATCH v9 09/10] serial: sc16is7xx: add post reset delay
From: Hugo Villeneuve <hvilleneuve@...onoff.com>
Make sure we wait at least 3us before initiating communication with
the device after reset.
Signed-off-by: Hugo Villeneuve <hvilleneuve@...onoff.com>
Reviewed-by: Lech Perczak <lech.perczak@...lingroup.com>
Tested-by: Lech Perczak <lech.perczak@...lingroup.com>
---
drivers/tty/serial/sc16is7xx.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 49213be60baf..718e982e1efe 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1526,6 +1526,12 @@ static int sc16is7xx_probe(struct device *dev,
regmap_write(s->regmap, SC16IS7XX_IOCONTROL_REG << SC16IS7XX_REG_SHIFT,
SC16IS7XX_IOCONTROL_SRESET_BIT);
+ /*
+ * After reset, the host must wait at least 3us before initializing a
+ * communication with the device.
+ */
+ usleep_range(5, 10);
+
for (i = 0; i < devtype->nr_uart; ++i) {
s->p[i].line = i;
/* Initialize port data */
--
2.30.2
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