serial: imx: add imx_poll_init()

For the console poll usage, .poll_init() will perform deeper hardware
initialization to ensure the serial port is always active.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Huang Shijie <b32955@freescale.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/imx.c

@@ -1455,6 +1455,41 @@ imx_verify_port(struct uart_port *port, struct serial_struct *ser)
 }
 
 #if defined(CONFIG_CONSOLE_POLL)
+
+static int imx_poll_init(struct uart_port *port)
+{
+	struct imx_port *sport = (struct imx_port *)port;
+	unsigned long flags;
+	unsigned long temp;
+	int retval;
+
+	retval = clk_prepare_enable(sport->clk_ipg);
+	if (retval)
+		return retval;
+	retval = clk_prepare_enable(sport->clk_per);
+	if (retval)
+		clk_disable_unprepare(sport->clk_ipg);
+
+	imx_setup_ufcr(sport, 0);
+
+	spin_lock_irqsave(&sport->port.lock, flags);
+
+	temp = readl(sport->port.membase + UCR1);
+	if (is_imx1_uart(sport))
+		temp |= IMX1_UCR1_UARTCLKEN;
+	temp |= UCR1_UARTEN | UCR1_RRDYEN;
+	temp &= ~(UCR1_TXMPTYEN | UCR1_RTSDEN);
+	writel(temp, sport->port.membase + UCR1);
+
+	temp = readl(sport->port.membase + UCR2);
+	temp |= UCR2_RXEN;
+	writel(temp, sport->port.membase + UCR2);
+
+	spin_unlock_irqrestore(&sport->port.lock, flags);
+
+	return 0;
+}
+
 static int imx_poll_get_char(struct uart_port *port)
 {
 	if (!(readl_relaxed(port->membase + USR2) & USR2_RDR))
@@ -1499,6 +1534,7 @@ static struct uart_ops imx_pops = {
 	.config_port	= imx_config_port,
 	.verify_port	= imx_verify_port,
 #if defined(CONFIG_CONSOLE_POLL)
+	.poll_init      = imx_poll_init,
 	.poll_get_char  = imx_poll_get_char,
 	.poll_put_char  = imx_poll_put_char,
 #endif