This is a note to let you know that I've just added the patch titled
tty: serial: owl: add "much needed" clk_prepare_enable()
to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From abf42d2f333b21bf8d33b2fbb8a85fa62037ac01 Mon Sep 17 00:00:00 2001
From: Amit Singh Tomar <amittomer25@xxxxxxxxx>
Date: Fri, 17 Apr 2020 01:41:57 +0530
Subject: tty: serial: owl: add "much needed" clk_prepare_enable()
commit 8ba92cf59335 ("arm64: dts: actions: s700: Add Clock Management Unit")
breaks the UART on Cubieboard7-lite (based on S700 SoC), This is due to the
fact that generic clk routine clk_disable_unused() disables the gate clks,
and that in turns disables OWL UART (but UART driver never enables it). To
prove this theory, Andre suggested to use "clk_ignore_unused" in kernel
commnd line and it worked (Kernel happily lands into RAMFS world :)).
This commit fix this up by adding clk_prepare_enable().
Fixes: 8ba92cf59335 ("arm64: dts: actions: s700: Add Clock Management Unit")
Signed-off-by: Amit Singh Tomar <amittomer25@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/1587067917-1400-1-git-send-email-amittomer25@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/owl-uart.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c
index 42c8cc93b603..c149f8c30007 100644
--- a/drivers/tty/serial/owl-uart.c
+++ b/drivers/tty/serial/owl-uart.c
@@ -680,6 +680,12 @@ static int owl_uart_probe(struct platform_device *pdev)
return PTR_ERR(owl_port->clk);
}
+ ret = clk_prepare_enable(owl_port->clk);
+ if (ret) {
+ dev_err(&pdev->dev, "could not enable clk\n");
+ return ret;
+ }
+
owl_port->port.dev = &pdev->dev;
owl_port->port.line = pdev->id;
owl_port->port.type = PORT_OWL;
@@ -712,6 +718,7 @@ static int owl_uart_remove(struct platform_device *pdev)
uart_remove_one_port(&owl_uart_driver, &owl_port->port);
owl_uart_ports[pdev->id] = NULL;
+ clk_disable_unprepare(owl_port->clk);
return 0;
}
--
2.26.2
