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@gmail.com 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@gmail.com Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/1587067917-1400-1-git-send-email-amittomer25@gmail... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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; }