Re: [PATCH 8/8] imx: serial: add IrDA support to serial driver

From: Oskar Schirmer
Date: Wed Jun 10 2009 - 03:01:21 EST

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On Tue, Jun 09, 2009 at 20:10:38 +0200, Sascha Hauer wrote:
> Hi Oskar,
>
> Some comments inline.
>
> On Tue, Jun 09, 2009 at 03:46:51PM +0200, Oskar Schirmer wrote:
> > From: Fabian Godehardt <fg@xxxxxxxxx>
> >
> > 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: Fabian Godehardt <fg@xxxxxxxxx>
> > Signed-off-by: Oskar Schirmer <os@xxxxxxxxx>
> > ---
> > arch/arm/mach-imx/include/mach/imx-uart.h | 4 +
> > drivers/serial/imx.c | 207 ++++++++++++++++++++++++++---
> > 2 files changed, 192 insertions(+), 19 deletions(-)
> >
> > diff --git a/arch/arm/mach-imx/include/mach/imx-uart.h b/arch/arm/mach-imx/include/mach/imx-uart.h
> > index d54eb1d..01ea268 100644
> > --- a/arch/arm/mach-imx/include/mach/imx-uart.h
> > +++ b/arch/arm/mach-imx/include/mach/imx-uart.h
> > @@ -2,11 +2,15 @@
> > #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);
> > void (*exit)(struct platform_device *pdev);
> > unsigned int flags;
> > +#ifdef CONFIG_IRDA
> > + void (*irda_enable)(int enable);
> > +#endif
>
> I think you shouldn't ifdef this field. Otherwise platform code needs
> exactly this ifdef aswell.

Right. I'll change that.

> > };
> >
> > #endif
> > diff --git a/drivers/serial/imx.c b/drivers/serial/imx.c
> > index 11f93e2..305b6bf 100644
> > --- a/drivers/serial/imx.c
> > +++ b/drivers/serial/imx.c
> > @@ -8,6 +8,9 @@
> > * Author: Sascha Hauer <sascha@xxxxxxxxxxxxxx>
> > * 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 +218,21 @@ struct imx_port {
> > unsigned int old_status;
> > int txirq,rxirq,rtsirq;
> > unsigned int have_rtscts:1;
> > +#ifdef CONFIG_IRDA
> > + unsigned int use_irda:1;
> > + unsigned int irda_inv_rx:1;
> > + unsigned int irda_inv_tx:1;
> > + int trcv_delay; /* transceiver delay */
> > +#endif
>
> You can't use USE_IRDA() several times in your patch because you ifdef
> these fields. Given the fact that these only add 4 bytes to struct
> imx_port you could remove the ifdef here and use USE_IRDA()
> consistently.

Ok.

> Do you need these fields anyway? Their values are hardcoded in the
> driver and can't be overridden by platform code.

We used to set them via sysfs, but we thought the patch for that
is not generically reusable. I'll see if I add the default settings
to platform data, so they wont be hardcoded but can be adjusted
to the hardware used as needed.

Oskar

>
> Sascha
>
> > 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 +286,50 @@ static void imx_stop_tx(struct uart_port *port)
> > struct imx_port *sport = (struct imx_port *)port;
> > unsigned long temp;
> >
> > +#ifdef CONFIG_IRDA
> > + if (sport->use_irda) {
> > + /* 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;
> > + }
> > +#endif
> > +
> > temp = readl(sport->port.membase + UCR1);
> > writel(temp & ~UCR1_TXMPTYEN, sport->port.membase + UCR1);
> > }
> > @@ -324,9 +385,30 @@ 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 +618,7 @@ 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 +637,24 @@ 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 +670,16 @@ static int imx_startup(struct uart_port *port)
> > if (retval)
> > goto error_out2;
> >
> > - retval = request_irq(sport->rtsirq, imx_rtsint,
> > - (sport->rtsirq < MAX_INTERNAL_IRQ) ? 0 :
> > - IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
> > - DRIVER_NAME, sport);
> > - if (retval)
> > - goto error_out3;
> > + /* 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,
> > + DRIVER_NAME, sport);
> > + if (retval)
> > + goto error_out3;
> > + }
> > } else {
> > retval = request_irq(sport->port.irq, imx_int, 0,
> > DRIVER_NAME, sport);
> > @@ -599,18 +696,51 @@ 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
> >
> > +#ifdef CONFIG_IRDA
> > + if (sport->use_irda) {
> > + 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);
> > + }
> > +#endif
> > +
> > /*
> > * Enable modem status interrupts
> > */
> > @@ -618,6 +748,15 @@ static int imx_startup(struct uart_port *port)
> > imx_enable_ms(&sport->port);
> > spin_unlock_irqrestore(&sport->port.lock,flags);
> >
> > +#ifdef CONFIG_IRDA
> > + if (sport->use_irda) {
> > + struct imxuart_platform_data *pdata;
> > + pdata = sport->port.dev->platform_data;
> > + if (pdata->irda_enable)
> > + pdata->irda_enable(1);
> > + }
> > +#endif
> > +
> > return 0;
> >
> > error_out3:
> > @@ -639,6 +778,15 @@ static void imx_shutdown(struct uart_port *port)
> > temp &= ~(UCR2_TXEN);
> > writel(temp, sport->port.membase + UCR2);
> >
> > +#ifdef CONFIG_IRDA
> > + if (sport->use_irda) {
> > + struct imxuart_platform_data *pdata;
> > + pdata = sport->port.dev->platform_data;
> > + if (pdata->irda_enable)
> > + pdata->irda_enable(0);
> > + }
> > +#endif
> > +
> > /*
> > * Stop our timer.
> > */
> > @@ -648,7 +796,8 @@ static void imx_shutdown(struct uart_port *port)
> > * Free the interrupts
> > */
> > if (sport->txirq > 0) {
> > - free_irq(sport->rtsirq, sport);
> > + if (!USE_IRDA(sport))
> > + free_irq(sport->rtsirq, sport);
> > free_irq(sport->txirq, sport);
> > free_irq(sport->rxirq, sport);
> > } else
> > @@ -660,6 +809,9 @@ 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 +920,19 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
> > sport->port.membase + UCR2);
> > old_txrxen &= (UCR2_TXEN | UCR2_RXEN);
> >
> > - div = sport->port.uartclk / (baud * 16);
> > - if (div > 7)
> > - div = 7;
> > - if (!div)
> > + 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 +941,7 @@ 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);
> > @@ -1139,6 +1298,16 @@ 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)) {
> > + /* set defaults */
> > + sport->irda_inv_rx = 0;
> > + sport->irda_inv_tx = 0;
> > + sport->trcv_delay = 50;
> > + sport->use_irda = 1;
> > + }
> > +#endif
> > +
> > if (pdata->init) {
> > ret = pdata->init(pdev);
> > if (ret)
> > --
> > 1.5.3.7
> >
> >
>
> --
> Pengutronix e.K. | |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
> Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
>

--
oskar schirmer, emlix gmbh, http://www.emlix.com
fon +49 551 30664-0, fax -11, bahnhofsallee 1b, 37081 gÃttingen, germany
geschÃftsfÃhrung: dr. uwe kracke, dr. cord seele, ust-idnr.: de 205 198 055
sitz der gesellschaft: gÃttingen, amtsgericht gÃttingen hr b 3160

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Next message: Stefani Seibold: "[patch 2/2] procfs: provide stack information for threads V0.8"
Previous message: Stephen Rothwell: "Re: linux-next: kbuild tree build warning"
In reply to: Sascha Hauer: "Re: [PATCH 8/8] imx: serial: add IrDA support to serial driver"
Next in thread: Sascha Hauer: "Re: [PATCH 6/8] lib: isolate rational fractions helper function"
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