From 534fca068ec8063ec8b67626b3eb34ba6ec86967 Mon Sep 17 00:00:00 2001 From: Oskar Schirmer Date: Thu, 11 Jun 2009 14:52:23 +0100 Subject: 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: Oskar Schirmer Signed-off-by: Alan Cox Signed-off-by: Linus Torvalds --- drivers/serial/Kconfig | 1 + drivers/serial/imx.c | 30 ++++++++++-------------------- 2 files changed, 11 insertions(+), 20 deletions(-) (limited to 'drivers/serial') diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index 3391ef0d761d..641e800ed693 100644 --- a/drivers/serial/Kconfig +++ b/drivers/serial/Kconfig @@ -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. diff --git a/drivers/serial/imx.c b/drivers/serial/imx.c index cbd4f3224643..0de81f71f884 100644 --- a/drivers/serial/imx.c +++ b/drivers/serial/imx.c @@ -41,6 +41,7 @@ #include #include #include +#include #include #include @@ -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; + num -= 1; + denom -= 1; 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 -- cgit v1.2.3