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Commit b6e49138 authored by Fabian Godehardt's avatar Fabian Godehardt Committed by Linus Torvalds
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imx: serial: add IrDA support to serial driver 



Using the iMX serial driver with an IrDA device
needs extra peripheral settings and specific
timing depending on the transmitter circuitry used.

Signed-off-by: default avatarFabian Godehardt <fg@emlix.com>
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 534fca06

arch/arm/plat-mxc/include/mach/imx-uart.h

+5 −0
Original line number Diff line number Diff line
@@ -20,11 +20,16 @@ 
#define ASMARM_ARCH_UART_H



#define IMXUART_HAVE_RTSCTS (1<<0)

#define IMXUART_IRDA        (1<<1)



struct imxuart_platform_data {

	int (*init)(struct platform_device *pdev);

	int (*exit)(struct platform_device *pdev);

	unsigned int flags;

	void (*irda_enable)(int enable);

	unsigned int irda_inv_rx:1;

	unsigned int irda_inv_tx:1;

	unsigned short transceiver_delay;

};



#endif

drivers/serial/imx.c

+176 −19
Original line number Diff line number Diff line
@@ -8,6 +8,9 @@ 
 *  Author: Sascha Hauer <sascha@saschahauer.de>

 *  Copyright (C) 2004 Pengutronix

 *

 *  Copyright (C) 2009 emlix GmbH

 *  Author: Fabian Godehardt (added IrDA support for iMX)

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or
@@ -41,6 +44,7 @@ 
#include <linux/serial_core.h>

#include <linux/serial.h>

#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/rational.h>



#include <asm/io.h>
@@ -149,6 +153,7 @@ 
#define  UCR4_DREN  	 (1<<0)  /* Recv data ready interrupt enable */

#define  UFCR_RXTL_SHF   0       /* Receiver trigger level shift */

#define  UFCR_RFDIV      (7<<7)  /* Reference freq divider mask */

#define  UFCR_RFDIV_REG(x)	(((x) < 7 ? 6 - (x) : 6) << 7)

#define  UFCR_TXTL_SHF   10      /* Transmitter trigger level shift */

#define  USR1_PARITYERR  (1<<15) /* Parity error interrupt flag */

#define  USR1_RTSS  	 (1<<14) /* RTS pin status */
@@ -213,9 +218,19 @@ struct imx_port { 
	unsigned int		old_status;

	int			txirq,rxirq,rtsirq;

	unsigned int		have_rtscts:1;

	unsigned int		use_irda:1;

	unsigned int		irda_inv_rx:1;

	unsigned int		irda_inv_tx:1;

	unsigned short		trcv_delay; /* transceiver delay */

	struct clk		*clk;

};



#ifdef CONFIG_IRDA

#define USE_IRDA(sport)	((sport)->use_irda)

#else

#define USE_IRDA(sport)	(0)

#endif



/*

 * Handle any change of modem status signal since we were last called.

 */
@@ -269,6 +284,48 @@ static void imx_stop_tx(struct uart_port *port) 
	struct imx_port *sport = (struct imx_port *)port;

	unsigned long temp;



	if (USE_IRDA(sport)) {

		/* half duplex - wait for end of transmission */

		int n = 256;

		while ((--n > 0) &&

		      !(readl(sport->port.membase + USR2) & USR2_TXDC)) {

			udelay(5);

			barrier();

		}

		/*

		 * irda transceiver - wait a bit more to avoid

		 * cutoff, hardware dependent

		 */

		udelay(sport->trcv_delay);



		/*

		 * half duplex - reactivate receive mode,

		 * flush receive pipe echo crap

		 */

		if (readl(sport->port.membase + USR2) & USR2_TXDC) {

			temp = readl(sport->port.membase + UCR1);

			temp &= ~(UCR1_TXMPTYEN | UCR1_TRDYEN);

			writel(temp, sport->port.membase + UCR1);



			temp = readl(sport->port.membase + UCR4);

			temp &= ~(UCR4_TCEN);

			writel(temp, sport->port.membase + UCR4);



			while (readl(sport->port.membase + URXD0) &

			       URXD_CHARRDY)

				barrier();



			temp = readl(sport->port.membase + UCR1);

			temp |= UCR1_RRDYEN;

			writel(temp, sport->port.membase + UCR1);



			temp = readl(sport->port.membase + UCR4);

			temp |= UCR4_DREN;

			writel(temp, sport->port.membase + UCR4);

		}

		return;

	}



	temp = readl(sport->port.membase + UCR1);

	writel(temp & ~UCR1_TXMPTYEN, sport->port.membase + UCR1);

}
@@ -324,9 +381,30 @@ static void imx_start_tx(struct uart_port *port) 
	struct imx_port *sport = (struct imx_port *)port;

	unsigned long temp;



	if (USE_IRDA(sport)) {

		/* half duplex in IrDA mode; have to disable receive mode */

		temp = readl(sport->port.membase + UCR4);

		temp &= ~(UCR4_DREN);

		writel(temp, sport->port.membase + UCR4);



		temp = readl(sport->port.membase + UCR1);

		temp &= ~(UCR1_RRDYEN);

		writel(temp, sport->port.membase + UCR1);

	}



	temp = readl(sport->port.membase + UCR1);

	writel(temp | UCR1_TXMPTYEN, sport->port.membase + UCR1);



	if (USE_IRDA(sport)) {

		temp = readl(sport->port.membase + UCR1);

		temp |= UCR1_TRDYEN;

		writel(temp, sport->port.membase + UCR1);



		temp = readl(sport->port.membase + UCR4);

		temp |= UCR4_TCEN;

		writel(temp, sport->port.membase + UCR4);

	}



	if (readl(sport->port.membase + UTS) & UTS_TXEMPTY)

		imx_transmit_buffer(sport);

}
@@ -536,12 +614,7 @@ static int imx_setup_ufcr(struct imx_port *sport, unsigned int mode) 
	if(!ufcr_rfdiv)

		ufcr_rfdiv = 1;



	if(ufcr_rfdiv >= 7)

		ufcr_rfdiv = 6;

	else

		ufcr_rfdiv = 6 - ufcr_rfdiv;



	val |= UFCR_RFDIV & (ufcr_rfdiv << 7);

	val |= UFCR_RFDIV_REG(ufcr_rfdiv);



	writel(val, sport->port.membase + UFCR);
@@ -560,8 +633,24 @@ static int imx_startup(struct uart_port *port) 
	 * requesting IRQs

	 */

	temp = readl(sport->port.membase + UCR4);



	if (USE_IRDA(sport))

		temp |= UCR4_IRSC;



	writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);



	if (USE_IRDA(sport)) {

		/* reset fifo's and state machines */

		int i = 100;

		temp = readl(sport->port.membase + UCR2);

		temp &= ~UCR2_SRST;

		writel(temp, sport->port.membase + UCR2);

		while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) &&

		    (--i > 0)) {

			udelay(1);

		}

	}



	/*

	 * Allocate the IRQ(s) i.MX1 has three interrupts whereas later

	 * chips only have one interrupt.
@@ -577,12 +666,16 @@ static int imx_startup(struct uart_port *port) 
		if (retval)

			goto error_out2;



		/* do not use RTS IRQ on IrDA */

		if (!USE_IRDA(sport)) {

			retval = request_irq(sport->rtsirq, imx_rtsint,

				     (sport->rtsirq < MAX_INTERNAL_IRQ) ? 0 :

			       IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,

				       IRQF_TRIGGER_FALLING |

				       IRQF_TRIGGER_RISING,

					DRIVER_NAME, sport);

			if (retval)

				goto error_out3;

		}

	} else {

		retval = request_irq(sport->port.irq, imx_int, 0,

				DRIVER_NAME, sport);
@@ -599,18 +692,49 @@ static int imx_startup(struct uart_port *port) 


	temp = readl(sport->port.membase + UCR1);

	temp |= UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN;



	if (USE_IRDA(sport)) {

		temp |= UCR1_IREN;

		temp &= ~(UCR1_RTSDEN);

	}



	writel(temp, sport->port.membase + UCR1);



	temp = readl(sport->port.membase + UCR2);

	temp |= (UCR2_RXEN | UCR2_TXEN);

	writel(temp, sport->port.membase + UCR2);



	if (USE_IRDA(sport)) {

		/* clear RX-FIFO */

		int i = 64;

		while ((--i > 0) &&

			(readl(sport->port.membase + URXD0) & URXD_CHARRDY)) {

			barrier();

		}

	}



#if defined CONFIG_ARCH_MX2 || defined CONFIG_ARCH_MX3

	temp = readl(sport->port.membase + UCR3);

	temp |= UCR3_RXDMUXSEL;

	writel(temp, sport->port.membase + UCR3);

#endif



	if (USE_IRDA(sport)) {

		temp = readl(sport->port.membase + UCR4);

		if (sport->irda_inv_rx)

			temp |= UCR4_INVR;

		else

			temp &= ~(UCR4_INVR);

		writel(temp | UCR4_DREN, sport->port.membase + UCR4);



		temp = readl(sport->port.membase + UCR3);

		if (sport->irda_inv_tx)

			temp |= UCR3_INVT;

		else

			temp &= ~(UCR3_INVT);

		writel(temp, sport->port.membase + UCR3);

	}



	/*

	 * Enable modem status interrupts

	 */
@@ -618,6 +742,16 @@ static int imx_startup(struct uart_port *port) 
	imx_enable_ms(&sport->port);

	spin_unlock_irqrestore(&sport->port.lock,flags);



	if (USE_IRDA(sport)) {

		struct imxuart_platform_data *pdata;

		pdata = sport->port.dev->platform_data;

		sport->irda_inv_rx = pdata->irda_inv_rx;

		sport->irda_inv_tx = pdata->irda_inv_tx;

		sport->trcv_delay = pdata->transceiver_delay;

		if (pdata->irda_enable)

			pdata->irda_enable(1);

	}



	return 0;



error_out3:
@@ -639,6 +773,13 @@ static void imx_shutdown(struct uart_port *port) 
	temp &= ~(UCR2_TXEN);

	writel(temp, sport->port.membase + UCR2);



	if (USE_IRDA(sport)) {

		struct imxuart_platform_data *pdata;

		pdata = sport->port.dev->platform_data;

		if (pdata->irda_enable)

			pdata->irda_enable(0);

	}



	/*

	 * Stop our timer.

	 */
@@ -648,6 +789,7 @@ static void imx_shutdown(struct uart_port *port) 
	 * Free the interrupts

	 */

	if (sport->txirq > 0) {

		if (!USE_IRDA(sport))

			free_irq(sport->rtsirq, sport);

		free_irq(sport->txirq, sport);

		free_irq(sport->rxirq, sport);
@@ -660,6 +802,9 @@ static void imx_shutdown(struct uart_port *port) 


	temp = readl(sport->port.membase + UCR1);

	temp &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN);

	if (USE_IRDA(sport))

		temp &= ~(UCR1_IREN);



	writel(temp, sport->port.membase + UCR1);

}
@@ -768,11 +913,19 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios, 
			sport->port.membase + UCR2);

	old_txrxen &= (UCR2_TXEN | UCR2_RXEN);



	if (USE_IRDA(sport)) {

		/*

		 * use maximum available submodule frequency to

		 * avoid missing short pulses due to low sampling rate

		 */

		div = 1;

	} else {

		div = sport->port.uartclk / (baud * 16);

		if (div > 7)

			div = 7;

		if (!div)

			div = 1;

	}



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

		1 << 16, 1 << 16, &num, &denom);
@@ -781,8 +934,7 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios, 
	denom -= 1;



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

	ufcr = (ufcr & (~UFCR_RFDIV)) |

	    (div << 7);

	ufcr = (ufcr & (~UFCR_RFDIV)) | UFCR_RFDIV_REG(div);

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



	writel(num, sport->port.membase + UBIR);
@@ -1141,6 +1293,11 @@ static int serial_imx_probe(struct platform_device *pdev) 
	if (pdata && (pdata->flags & IMXUART_HAVE_RTSCTS))

		sport->have_rtscts = 1;



#ifdef CONFIG_IRDA

	if (pdata && (pdata->flags & IMXUART_IRDA))

		sport->use_irda = 1;

#endif



	if (pdata->init) {

		ret = pdata->init(pdev);

		if (ret)