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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 <os@emlix.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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8759ef32d9
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534fca068e
2 changed files with 11 additions and 20 deletions
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@ -833,6 +833,7 @@ config SERIAL_IMX
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bool "IMX serial port support"
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depends on ARM && (ARCH_IMX || ARCH_MXC)
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select SERIAL_CORE
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select RATIONAL
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help
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If you have a machine based on a Motorola IMX CPU you
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can enable its onboard serial port by enabling this option.
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@ -41,6 +41,7 @@
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#include <linux/serial_core.h>
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#include <linux/serial.h>
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#include <linux/clk.h>
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#include <linux/rational.h>
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#include <asm/io.h>
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#include <asm/irq.h>
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@ -670,7 +671,8 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
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unsigned long flags;
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unsigned int ucr2, old_ucr1, old_txrxen, baud, quot;
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unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
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unsigned int div, num, denom, ufcr;
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unsigned int div, ufcr;
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unsigned long num, denom;
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/*
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* If we don't support modem control lines, don't allow
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@ -772,32 +774,20 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
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if (!div)
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div = 1;
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num = baud;
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denom = port->uartclk / div / 16;
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rational_best_approximation(16 * div * baud, sport->port.uartclk,
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1 << 16, 1 << 16, &num, &denom);
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/* shift num and denom right until they fit into 16 bits */
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while (num > 0x10000 || denom > 0x10000) {
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num >>= 1;
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denom >>= 1;
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}
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if (num > 0)
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num -= 1;
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if (denom > 0)
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denom -= 1;
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writel(num, sport->port.membase + UBIR);
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writel(denom, sport->port.membase + UBMR);
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if (div == 7)
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div = 6; /* 6 in RFDIV means divide by 7 */
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else
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div = 6 - div;
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num -= 1;
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denom -= 1;
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ufcr = readl(sport->port.membase + UFCR);
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ufcr = (ufcr & (~UFCR_RFDIV)) |
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(div << 7);
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writel(ufcr, sport->port.membase + UFCR);
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writel(num, sport->port.membase + UBIR);
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writel(denom, sport->port.membase + UBMR);
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#ifdef ONEMS
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writel(sport->port.uartclk / div / 1000, sport->port.membase + ONEMS);
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#endif
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