linux-kernel - [PATCH v5 2/3] serial: 8250_dw: Simplify the ref clock rate setting procedure

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Message-ID: <20200526181227.1889-3-Sergey.Semin@baikalelectronics.ru>
Date:   Tue, 26 May 2020 21:12:25 +0300
From:   Serge Semin <Sergey.Semin@...kalelectronics.ru>
To:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
CC:     Serge Semin <Sergey.Semin@...kalelectronics.ru>,
        Serge Semin <fancer.lancer@...il.com>,
        Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>,
        Arnd Bergmann <arnd@...db.de>,
        Maxime Ripard <mripard@...nel.org>,
        Will Deacon <will@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        <linux-mips@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-serial@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v5 2/3] serial: 8250_dw: Simplify the ref clock rate setting procedure

Really instead of twice checking the clk_round_rate() return value
we could do it once, and if it isn't error the clock rate can be changed.
By doing so we decrease a number of ret-value tests and remove a weird
goto-based construction implemented in the dw8250_set_termios() method.

Signed-off-by: Serge Semin <Sergey.Semin@...kalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Maxime Ripard <mripard@...nel.org>
Cc: Will Deacon <will@...nel.org>
Cc: Russell King <linux@...linux.org.uk>
Cc: linux-mips@...r.kernel.org
Cc: linux-arm-kernel@...ts.infradead.org

---

Changelog v3:
- This is a new patch.
---
 drivers/tty/serial/8250/8250_dw.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index aab3cccc6789..12866083731d 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -282,20 +282,13 @@ 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);
-	if (rate < 0)
-		ret = rate;
-	else if (rate == 0)
-		ret = -ENOENT;
-	else
+	if (rate > 0) {
 		ret = clk_set_rate(d->clk, rate);
+		if (!ret)
+			p->uartclk = rate;
+	}
 	clk_prepare_enable(d->clk);
 
-	if (ret)
-		goto out;
-
-	p->uartclk = rate;
-
-out:
 	p->status &= ~UPSTAT_AUTOCTS;
 	if (termios->c_cflag & CRTSCTS)
 		p->status |= UPSTAT_AUTOCTS;
-- 
2.26.2