Thread (2 messages) 2 messages, 2 authors, 2017-02-28

Re: [PATCH] serial: 8250_dw: Honor clk_round_rate errors in dw8250_set_termios

From: Andy Shevchenko <hidden>
Date: 2017-02-28 14:03:43
Also in: lkml

On Tue, Feb 28, 2017 at 5:17 AM, Heiko Stuebner [off-list ref] wrote:
clk_round_rate returns a signed long and may possibly return errors
in it, for example if there is no possible rate.

Till now dw8250_set_termios ignored any error, the signednes and would
just use the value as input to clk_set_rate. This of course falls apart
if there is an actual error, so check for errors and only try to set
a rate if the value is actually valid.
FWIW:
Reviewed-by: Andy Shevchenko <redacted>
quoted hunk ↗ jump to hunk
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
 drivers/tty/serial/8250/8250_dw.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 6ee55a2d47bb..223ac234ddb2 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -257,7 +257,7 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
 {
        unsigned int baud = tty_termios_baud_rate(termios);
        struct dw8250_data *d = p->private_data;
-       unsigned int rate;
+       long rate;
        int ret;

        if (IS_ERR(d->clk) || !old)
@@ -265,7 +265,10 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,

        clk_disable_unprepare(d->clk);
        rate = clk_round_rate(d->clk, baud * 16);
-       ret = clk_set_rate(d->clk, rate);
+       if (rate < 0)
+               ret = rate;
+       else
+               ret = clk_set_rate(d->clk, rate);
        clk_prepare_enable(d->clk);

        if (!ret)
--
2.11.0


-- 
With Best Regards,
Andy Shevchenko
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