This is a note to let you know that I've just added the patch titled
serial: sc16is7xx: fix broken port 0 uart init
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
serial-sc16is7xx-fix-broken-port-0-uart-init.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2861ed4d6e6d1a2c9de9bf5b0abd996c2dc673d0 Mon Sep 17 00:00:00 2001
From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
Date: Mon, 7 Aug 2023 17:45:51 -0400
Subject: serial: sc16is7xx: fix broken port 0 uart init
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
commit 2861ed4d6e6d1a2c9de9bf5b0abd996c2dc673d0 upstream.
The sc16is7xx_config_rs485() function is called only for the second
port (index 1, channel B), causing initialization problems for the
first port.
For the sc16is7xx driver, port->membase and port->mapbase are not set,
and their default values are 0. And we set port->iobase to the device
index. This means that when the first device is registered using the
uart_add_one_port() function, the following values will be in the port
structure:
port->membase = 0
port->mapbase = 0
port->iobase = 0
Therefore, the function uart_configure_port() in serial_core.c will
exit early because of the following check:
/*
* If there isn't a port here, don't do anything further.
*/
if (!port->iobase && !port->mapbase && !port->membase)
return;
Typically, I2C and SPI drivers do not set port->membase and
port->mapbase.
The max310x driver sets port->membase to ~0 (all ones). By
implementing the same change in this driver, uart_configure_port() is
now correctly executed for all ports.
Fixes: dfeae619d781 ("serial: sc16is7xx")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Reviewed-by: Lech Perczak <lech.perczak@xxxxxxxxxxxxxxx>
Tested-by: Lech Perczak <lech.perczak@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230807214556.540627-2-hugo@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/sc16is7xx.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1436,6 +1436,12 @@ static int sc16is7xx_probe(struct device
s->p[i].port.fifosize = SC16IS7XX_FIFO_SIZE;
s->p[i].port.flags = UPF_FIXED_TYPE | UPF_LOW_LATENCY;
s->p[i].port.iobase = i;
+ /*
+ * Use all ones as membase to make sure uart_configure_port() in
+ * serial_core.c does not abort for SPI/I2C devices where the
+ * membase address is not applicable.
+ */
+ s->p[i].port.membase = (void __iomem *)~0;
s->p[i].port.iotype = UPIO_PORT;
s->p[i].port.uartclk = freq;
s->p[i].port.rs485_config = sc16is7xx_config_rs485;
Patches currently in stable-queue which might be from hvilleneuve@xxxxxxxxxxxx are
queue-6.4/serial-sc16is7xx-fix-broken-port-0-uart-init.patch
queue-6.4/serial-sc16is7xx-fix-bug-when-first-setting-gpio-direction.patch
queue-6.4/dt-bindings-sc16is7xx-add-property-to-change-gpio-function.patch
