From: Matthew Howell <matthew.howell@sealevel.com>
To: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: "linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
Darren Beeson <darren.beeson@sealevel.com>,
Jeff Baldwin <jeff.baldwin@sealevel.com>,
Ryan Wenglarz <ryan.wenglarz@sealevel.com>
Subject: [PATCH V1] serial: exar: Preserve FCTR[5] bit in pci_xr17v35x_setup()
Date: Wed, 21 Feb 2024 21:06:49 +0000 [thread overview]
Message-ID: <5dd9f8b0c1dc154c73fb883cb948768ae68d1ccb.camel@sealevel.com> (raw)
Allows the use of the EN485 hardware pin by preserving the value of
FCTR[5] in pci_xr17v35x_setup().
Per the XR17V35X datasheet, the EN485 hardware pin works by setting
FCTR[5] when the pin is active. pci_xr17v35x_setup() prevented the use
of EN485 because it overwrote the FCTR register.
Signed-off-by: Matthew Howell <matthew.howell@sealevel.com>
---
diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
index 23366f868..97711606f 100644
--- a/drivers/tty/serial/8250/8250_exar.c
+++ b/drivers/tty/serial/8250/8250_exar.c
@@ -596,6 +596,7 @@ pci_xr17v35x_setup(struct exar8250 *priv, struct pci_dev *pcidev,
unsigned int baud = 7812500;
u8 __iomem *p;
int ret;
+ u8 en485mask;
port->port.uartclk = baud * 16;
port->port.rs485_config = platform->rs485_config;
@@ -618,7 +619,8 @@ pci_xr17v35x_setup(struct exar8250 *priv, struct pci_dev *pcidev,
p = port->port.membase;
writeb(0x00, p + UART_EXAR_8XMODE);
- writeb(UART_FCTR_EXAR_TRGD, p + UART_EXAR_FCTR);
+ en485mask = readb(p + UART_EXAR_FCTR) & UART_FCTR_EXAR_485;
+ writeb(UART_FCTR_EXAR_TRGD | en485mask, p + UART_EXAR_FCTR);
writeb(128, p + UART_EXAR_TXTRG);
writeb(128, p + UART_EXAR_RXTRG);
next reply other threads:[~2024-02-21 21:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-21 21:06 Matthew Howell [this message]
2024-02-21 21:16 ` [PATCH V2] serial: exar: Preserve FCTR[5] bit in pci_xr17v35x_setup() Matthew Howell
2024-02-21 22:58 ` andy.shevchenko
2024-04-09 13:01 ` Matthew Howell
2024-04-08 13:11 ` Matthew Howell
2024-04-08 14:56 ` gregkh
2024-04-09 12:33 ` Matthew Howell
2024-04-08 16:48 ` Ilpo Järvinen
2024-04-08 17:25 ` Ilpo Järvinen
2024-04-08 20:27 ` Matthew Howell
2024-04-10 13:49 ` Ilpo Järvinen
2024-04-10 16:20 ` Matthew Howell
2024-04-11 8:27 ` Ilpo Järvinen
2024-04-11 17:01 ` Matthew Howell
2024-04-11 20:44 ` Matthew Howell
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