Subject: imx uart: do not assume 16 MHz reference frequency From: Sascha Hauer We assumed a 16MHz reference frequency for the UART. While this is true for i.MX1 most of the time it is not true for MX27/MX31. This calculation has been taken from the freescale bsp code. Also, add handling for the ONEMS register which is present on newer versions of the chip. Signed-off-by: Sascha Hauer --- drivers/serial/imx.c | 32 ++++++++++++++++++++++---------- 1 file changed, 22 insertions(+), 10 deletions(-) Index: linux-2.6.26-rc6/drivers/serial/imx.c =================================================================== --- linux-2.6.26-rc6.orig/drivers/serial/imx.c +++ linux-2.6.26-rc6/drivers/serial/imx.c @@ -589,6 +589,7 @@ imx_set_termios(struct uart_port *port, 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; /* * If we don't support modem control lines, don't allow @@ -684,14 +685,25 @@ imx_set_termios(struct uart_port *port, sport->port.membase + UCR2); old_txrxen &= (UCR2_TXEN | UCR2_RXEN); - /* set the baud rate. We assume uartclk = 16 MHz - * - * baud * 16 UBIR - 1 - * --------- = -------- - * uartclk UBMR - 1 - */ - writel((baud / 100) - 1, sport->port.membase + UBIR); - writel(10000 - 1, sport->port.membase + UBMR); + div = sport->port.uartclk / ((baud * 16) + 1000); + if (div > 6) + div = 6; + + num = (baud / 100) - 1; + denom = (sport->port.uartclk / div / 1600) - 1; + if ((denom < 65536) && (sport->port.uartclk > 1600)) { + writel(num, sport->port.membase + UBIR); + writel(denom, sport->port.membase + UBMR); + } + + ufcr = readl(sport->port.membase + UFCR); + ufcr = (ufcr & (~UFCR_RFDIV)) | + ((6 - div) << 7); + writel(ufcr, sport->port.membase + UFCR); + +#ifdef ONEMS + writel(sport->port.uartclk / div / 1000, sport->port.membase + ONEMS); +#endif writel(old_ucr1, sport->port.membase + UCR1); @@ -812,7 +824,6 @@ static struct imx_port imx_ports[] = { .membase = (void *)IMX_UART1_BASE, .mapbase = 0x00206000, .irq = UART1_MINT_RX, - .uartclk = 16000000, .fifosize = 32, .flags = UPF_BOOT_AUTOCONF, .ops = &imx_pops, @@ -828,7 +839,6 @@ static struct imx_port imx_ports[] = { .membase = (void *)IMX_UART2_BASE, .mapbase = 0x00207000, .irq = UART2_MINT_RX, - .uartclk = 16000000, .fifosize = 32, .flags = UPF_BOOT_AUTOCONF, .ops = &imx_pops, @@ -858,6 +868,8 @@ static void __init imx_init_ports(void) init_timer(&imx_ports[i].timer); imx_ports[i].timer.function = imx_timeout; imx_ports[i].timer.data = (unsigned long)&imx_ports[i]; + + imx_ports[i].port.uartclk = imx_get_perclk1(); } }