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Commit 534fca06 authored by Oskar Schirmer's avatar Oskar Schirmer Committed by Linus Torvalds
Browse files

imx: serial: use rational library function 



for calculation of numerator and denominator
used in baud rate setting, use generic library function
for optimum settings.

Signed-off-by: default avatarOskar Schirmer <os@emlix.com>
Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8759ef32

drivers/serial/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -833,6 +833,7 @@ config SERIAL_IMX 
	bool "IMX serial port support"

	depends on ARM && (ARCH_IMX || ARCH_MXC)

	select SERIAL_CORE

	select RATIONAL

	help

	  If you have a machine based on a Motorola IMX CPU you

	  can enable its onboard serial port by enabling this option.

drivers/serial/imx.c

+10 −20
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
#include <linux/serial_core.h>

#include <linux/serial.h>

#include <linux/clk.h>

#include <linux/rational.h>



#include <asm/io.h>

#include <asm/irq.h>
@@ -670,7 +671,8 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios, 
	unsigned long flags;

	unsigned int ucr2, old_ucr1, old_txrxen, baud, quot;

	unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;

	unsigned int div, num, denom, ufcr;

	unsigned int div, ufcr;

	unsigned long num, denom;



	/*

	 * If we don't support modem control lines, don't allow
@@ -772,32 +774,20 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios, 
	if (!div)

		div = 1;



	num = baud;

	denom = port->uartclk / div / 16;

	rational_best_approximation(16 * div * baud, sport->port.uartclk,

		1 << 16, 1 << 16, &num, &denom);



	/* shift num and denom right until they fit into 16 bits */

	while (num > 0x10000 || denom > 0x10000) {

		num >>= 1;

		denom >>= 1;

	}

	if (num > 0)

	num -= 1;

	if (denom > 0)

	denom -= 1;



	writel(num, sport->port.membase + UBIR);

	writel(denom, sport->port.membase + UBMR);



	if (div == 7)

		div = 6; /* 6 in RFDIV means divide by 7 */

	else

		div = 6 - div;



	ufcr = readl(sport->port.membase + UFCR);

	ufcr = (ufcr & (~UFCR_RFDIV)) |

	    (div << 7);

	writel(ufcr, sport->port.membase + UFCR);



	writel(num, sport->port.membase + UBIR);

	writel(denom, sport->port.membase + UBMR);



#ifdef ONEMS

	writel(sport->port.uartclk / div / 1000, sport->port.membase + ONEMS);

#endif