Re: [PATCHv2 1/2] media: rc: Introduce RX51 IR transmitter driver

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On Fri, Aug 10, 2012 at 01:16:36PM +0300, Timo Kokkonen wrote:
> This is the driver for the IR transmitter diode found on the Nokia
> N900 (also known as RX51) device. The driver is mostly the same as
> found in the original 2.6.28 based kernel that comes with the device.
> 
> The following modifications have been made compared to the original
> driver version:
> 
> - Adopt to the changes that has happen in the kernel during the past
>   five years, such as the change in the include paths
> 
> - The OMAP DM-timers require much more care nowadays. The timers need
>   to be enabled and disabled or otherwise many actions fail. Timers
>   must not be freed without first stopping them or otherwise the timer
>   cannot be requested again.
> 
> The code has been tested with sending IR codes with N900 device
> running Debian userland. The device receiving the codes was Anysee
> DVB-C USB receiver.
> 
> Signed-off-by: Timo Kokkonen <timo.t.kokkonen@xxxxxx>
> ---
>  drivers/media/rc/Kconfig   |   10 +
>  drivers/media/rc/Makefile  |    1 +
>  drivers/media/rc/ir-rx51.c |  496 ++++++++++++++++++++++++++++++++++++++++++++
>  include/media/ir-rx51.h    |   10 +
>  4 files changed, 517 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/media/rc/ir-rx51.c
>  create mode 100644 include/media/ir-rx51.h
> 
> diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig
> index 5180390..ab35d2e 100644
> --- a/drivers/media/rc/Kconfig
> +++ b/drivers/media/rc/Kconfig
> @@ -270,6 +270,16 @@ config IR_IGUANA
>  	   To compile this driver as a module, choose M here: the module will
>  	   be called iguanair.
>  
> +config IR_RX51
> +	tristate "Nokia N900 IR transmitter diode
> +	depends on MACH_NOKIA_RX51 && OMAP_DM_TIMER
> +	---help---
> +	   Say Y or M here if you want to enable support for the IR
> +	   transmitter diode built in the Nokia N900 (RX51) device.
> +
> +	   The driver uses omap DM timers for gereating the carrier
> +	   wave and pulses.
> +
>  config RC_LOOPBACK
>  	tristate "Remote Control Loopback Driver"
>  	depends on RC_CORE
> diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile
> index f871d19..d384f30 100644
> --- a/drivers/media/rc/Makefile
> +++ b/drivers/media/rc/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_IR_FINTEK) += fintek-cir.o
>  obj-$(CONFIG_IR_NUVOTON) += nuvoton-cir.o
>  obj-$(CONFIG_IR_ENE) += ene_ir.o
>  obj-$(CONFIG_IR_REDRAT3) += redrat3.o
> +obj-$(CONFIG_IR_RX51) += ir-rx51.o
>  obj-$(CONFIG_IR_STREAMZAP) += streamzap.o
>  obj-$(CONFIG_IR_WINBOND_CIR) += winbond-cir.o
>  obj-$(CONFIG_RC_LOOPBACK) += rc-loopback.o
> diff --git a/drivers/media/rc/ir-rx51.c b/drivers/media/rc/ir-rx51.c
> new file mode 100644
> index 0000000..9487dd3
> --- /dev/null
> +++ b/drivers/media/rc/ir-rx51.c
> @@ -0,0 +1,496 @@
> +/*
> + *  Copyright (C) 2008 Nokia Corporation
> + *
> + *  Based on lirc_serial.c
> + *
> + *  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
> + *  (at your option) any later version.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with this program; if not, write to the Free Software
> + *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/uaccess.h>
> +#include <linux/platform_device.h>
> +#include <linux/sched.h>
> +#include <linux/wait.h>
> +
> +#include <plat/dmtimer.h>
> +#include <plat/clock.h>
> +#include <plat/omap-pm.h>
> +
> +#include <media/lirc.h>
> +#include <media/lirc_dev.h>
> +#include <media/ir-rx51.h>
> +
> +#define LIRC_RX51_DRIVER_FEATURES (LIRC_CAN_SET_SEND_DUTY_CYCLE |	\
> +				   LIRC_CAN_SET_SEND_CARRIER |		\
> +				   LIRC_CAN_SEND_PULSE)
> +
> +#define DRIVER_NAME "lirc_rx51"
> +
> +#define WBUF_LEN 256
> +
> +#define TIMER_MAX_VALUE 0xffffffff
> +
> +struct lirc_rx51 {
> +	struct omap_dm_timer *pwm_timer;
> +	struct omap_dm_timer *pulse_timer;
> +	struct device	     *dev;
> +	struct lirc_rx51_platform_data *pdata;
> +	wait_queue_head_t     wqueue;
> +
> +	unsigned long	fclk_khz;
> +	unsigned int	freq;		/* carrier frequency */
> +	unsigned int	duty_cycle;	/* carrier duty cycle */
> +	unsigned int	irq_num;
> +	unsigned int	match;
> +	int		wbuf[WBUF_LEN];
> +	int		wbuf_index;
> +	unsigned long	device_is_open;
> +	unsigned int	pwm_timer_num;
> +};
> +
> +static void lirc_rx51_on(struct lirc_rx51 *lirc_rx51)
> +{
> +	omap_dm_timer_set_pwm(lirc_rx51->pwm_timer, 0, 1,
> +			      OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE);
> +}
> +
> +static void lirc_rx51_off(struct lirc_rx51 *lirc_rx51)
> +{
> +	omap_dm_timer_set_pwm(lirc_rx51->pwm_timer, 0, 1,
> +			      OMAP_TIMER_TRIGGER_NONE);
> +}
> +
> +static int init_timing_params(struct lirc_rx51 *lirc_rx51)
> +{
> +	u32 load, match;
> +
> +	load = -(lirc_rx51->fclk_khz * 1000 / lirc_rx51->freq);
> +	match = -(lirc_rx51->duty_cycle * -load / 100);
> +	omap_dm_timer_set_load(lirc_rx51->pwm_timer, 1, load);
> +	omap_dm_timer_set_match(lirc_rx51->pwm_timer, 1, match);
> +	omap_dm_timer_write_counter(lirc_rx51->pwm_timer, TIMER_MAX_VALUE - 2);
> +	omap_dm_timer_start(lirc_rx51->pwm_timer);
> +	omap_dm_timer_set_int_enable(lirc_rx51->pulse_timer, 0);
> +	omap_dm_timer_start(lirc_rx51->pulse_timer);
> +
> +	lirc_rx51->match = 0;
> +
> +	return 0;
> +}
> +
> +#define tics_after(a, b) ((long)(b) - (long)(a) < 0)
> +
> +static int pulse_timer_set_timeout(struct lirc_rx51 *lirc_rx51, int usec)
> +{
> +	int counter;
> +
> +	BUG_ON(usec < 0);
> +
> +	if (lirc_rx51->match == 0)
> +		counter = omap_dm_timer_read_counter(lirc_rx51->pulse_timer);
> +	else
> +		counter = lirc_rx51->match;
> +
> +	counter += (u32)(lirc_rx51->fclk_khz * usec / (1000));
> +	omap_dm_timer_set_match(lirc_rx51->pulse_timer, 1, counter);
> +	omap_dm_timer_set_int_enable(lirc_rx51->pulse_timer,
> +				     OMAP_TIMER_INT_MATCH);
> +	if (tics_after(omap_dm_timer_read_counter(lirc_rx51->pulse_timer),
> +		       counter)) {
> +		return 1;
> +	}
> +	return 0;
> +}
> +
> +static irqreturn_t lirc_rx51_interrupt_handler(int irq, void *ptr)
> +{
> +	unsigned int retval;
> +	struct lirc_rx51 *lirc_rx51 = ptr;
> +
> +	retval = omap_dm_timer_read_status(lirc_rx51->pulse_timer);
> +	if (!retval)
> +		return IRQ_NONE;
> +
> +	if ((retval & ~OMAP_TIMER_INT_MATCH))
> +		dev_err_ratelimited(lirc_rx51->dev,
> +				": Unexpected interrupt source: %x\n", retval);
> +
> +	omap_dm_timer_write_status(lirc_rx51->pulse_timer, 7);
> +	if (lirc_rx51->wbuf_index < 0) {
> +		dev_err_ratelimited(lirc_rx51->dev,
> +				": BUG wbuf_index has value of %i\n",
> +				lirc_rx51->wbuf_index);
> +		goto end;
> +	}
> +
> +	/*
> +	 * If we happen to hit an odd latency spike, loop through the
> +	 * pulses until we catch up.
> +	 */
> +	do {
> +		if (lirc_rx51->wbuf_index >= WBUF_LEN)
> +			goto end;
> +		if (lirc_rx51->wbuf[lirc_rx51->wbuf_index] == -1)
> +			goto end;
> +
> +		if (lirc_rx51->wbuf_index % 2)
> +			lirc_rx51_off(lirc_rx51);
> +		else
> +			lirc_rx51_on(lirc_rx51);
> +
> +		retval = pulse_timer_set_timeout(lirc_rx51,
> +					lirc_rx51->wbuf[lirc_rx51->wbuf_index]);
> +		lirc_rx51->wbuf_index++;
> +
> +	} while (retval);
> +
> +	return IRQ_HANDLED;
> +end:
> +	/* Stop TX here */
> +	lirc_rx51_off(lirc_rx51);
> +	lirc_rx51->wbuf_index = -1;
> +	omap_dm_timer_stop(lirc_rx51->pwm_timer);
> +	omap_dm_timer_stop(lirc_rx51->pulse_timer);
> +	omap_dm_timer_set_int_enable(lirc_rx51->pulse_timer, 0);
> +	wake_up_interruptible(&lirc_rx51->wqueue);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int lirc_rx51_init_port(struct lirc_rx51 *lirc_rx51)
> +{
> +	struct clk *clk_fclk;
> +	int retval, pwm_timer = lirc_rx51->pwm_timer_num;
> +
> +	lirc_rx51->pwm_timer = omap_dm_timer_request_specific(pwm_timer);
> +	if (lirc_rx51->pwm_timer == NULL) {
> +		dev_err(lirc_rx51->dev, ": Error requesting GPT%d timer\n",
> +			pwm_timer);
> +		return -EBUSY;
> +	}
> +
> +	lirc_rx51->pulse_timer = omap_dm_timer_request();
> +	if (lirc_rx51->pulse_timer == NULL) {
> +		dev_err(lirc_rx51->dev, ": Error requesting pulse timer\n");
> +		retval = -EBUSY;
> +		goto err1;
> +	}
> +
> +	omap_dm_timer_set_source(lirc_rx51->pwm_timer, OMAP_TIMER_SRC_SYS_CLK);
> +	omap_dm_timer_set_source(lirc_rx51->pulse_timer,
> +				OMAP_TIMER_SRC_SYS_CLK);
> +
> +	omap_dm_timer_enable(lirc_rx51->pwm_timer);
> +	omap_dm_timer_enable(lirc_rx51->pulse_timer);
> +
> +	lirc_rx51->irq_num = omap_dm_timer_get_irq(lirc_rx51->pulse_timer);
> +	retval = request_irq(lirc_rx51->irq_num, lirc_rx51_interrupt_handler,
> +			     IRQF_DISABLED | IRQF_SHARED,
> +			     "lirc_pulse_timer", lirc_rx51);
> +	if (retval) {
> +		dev_err(lirc_rx51->dev, ": Failed to request interrupt line\n");
> +		goto err2;
> +	}
> +
> +	clk_fclk = omap_dm_timer_get_fclk(lirc_rx51->pwm_timer);
> +	lirc_rx51->fclk_khz = clk_fclk->rate / 1000;
> +
> +	return 0;
> +
> +err2:
> +	omap_dm_timer_free(lirc_rx51->pulse_timer);
> +err1:
> +	omap_dm_timer_free(lirc_rx51->pwm_timer);
> +
> +	return retval;
> +}
> +
> +static int lirc_rx51_free_port(struct lirc_rx51 *lirc_rx51)
> +{
> +	omap_dm_timer_set_int_enable(lirc_rx51->pulse_timer, 0);
> +	free_irq(lirc_rx51->irq_num, lirc_rx51);
> +	lirc_rx51_off(lirc_rx51);
> +	omap_dm_timer_disable(lirc_rx51->pwm_timer);
> +	omap_dm_timer_disable(lirc_rx51->pulse_timer);
> +	omap_dm_timer_free(lirc_rx51->pwm_timer);
> +	omap_dm_timer_free(lirc_rx51->pulse_timer);
> +	lirc_rx51->wbuf_index = -1;
> +
> +	return 0;
> +}
> +
> +static ssize_t lirc_rx51_write(struct file *file, const char *buf,
> +			  size_t n, loff_t *ppos)
> +{
> +	int count, i;
> +	struct lirc_rx51 *lirc_rx51 = file->private_data;
> +
> +	if (n % sizeof(int))
> +		return -EINVAL;
> +
> +	count = n / sizeof(int);
> +	if ((count > WBUF_LEN) || (count % 2 == 0))
> +		return -EINVAL;
> +
> +	/* Wait any pending transfers to finish */
> +	wait_event_interruptible(lirc_rx51->wqueue, lirc_rx51->wbuf_index < 0);

If a signal arrives then this could return ERESTARTSYS and the condition
might not have evaluated to true.

> +
> +	if (copy_from_user(lirc_rx51->wbuf, buf, n))
> +		return -EFAULT;
> +
> +	/* Sanity check the input pulses */
> +	for (i = 0; i < count; i++)
> +		if (lirc_rx51->wbuf[i] < 0)
> +			return -EINVAL;
> +
> +	init_timing_params(lirc_rx51);
> +	if (count < WBUF_LEN)
> +		lirc_rx51->wbuf[count] = -1; /* Insert termination mark */
> +
> +	/*
> +	 * Adjust latency requirements so the device doesn't go in too
> +	 * deep sleep states
> +	 */
> +	lirc_rx51->pdata->set_max_mpu_wakeup_lat(lirc_rx51->dev, 50);
> +
> +	lirc_rx51_on(lirc_rx51);
> +	lirc_rx51->wbuf_index = 1;
> +	pulse_timer_set_timeout(lirc_rx51, lirc_rx51->wbuf[0]);
> +
> +	/*
> +	 * Don't return back to the userspace until the transfer has
> +	 * finished
> +	 */
> +	wait_event_interruptible(lirc_rx51->wqueue, lirc_rx51->wbuf_index < 0);

same here.

BTW so the semantics for lirc write() are that they complete when the 
data has been transmitted. This doesn't play well with signals, polling 
or non-blocking I/O. Is this deliberate or historical?

I guess a lirc write() handler should ignore signals completely.

> +
> +	/* We can sleep again */
> +	lirc_rx51->pdata->set_max_mpu_wakeup_lat(lirc_rx51->dev, -1);
> +
> +	return n;
> +}
> +
> +static long lirc_rx51_ioctl(struct file *filep,
> +			unsigned int cmd, unsigned long arg)
> +{
> +	int result;
> +	unsigned long value;
> +	unsigned int ivalue;
> +	struct lirc_rx51 *lirc_rx51 = filep->private_data;
> +
> +	switch (cmd) {
> +	case LIRC_GET_SEND_MODE:
> +		result = put_user(LIRC_MODE_PULSE, (unsigned long *)arg);
> +		if (result)
> +			return result;
> +		break;
> +
> +	case LIRC_SET_SEND_MODE:
> +		result = get_user(value, (unsigned long *)arg);
> +		if (result)
> +			return result;
> +
> +		/* only LIRC_MODE_PULSE supported */
> +		if (value != LIRC_MODE_PULSE)
> +			return -ENOSYS;
> +		break;
> +
> +	case LIRC_GET_REC_MODE:
> +		result = put_user(0, (unsigned long *) arg);
> +		if (result)
> +			return result;
> +		break;
> +
> +	case LIRC_GET_LENGTH:
> +		return -ENOSYS;
> +		break;
> +
> +	case LIRC_SET_SEND_DUTY_CYCLE:
> +		result = get_user(ivalue, (unsigned int *) arg);
> +		if (result)
> +			return result;
> +
> +		if (ivalue <= 0 || ivalue > 100) {
> +			dev_err(lirc_rx51->dev, ": invalid duty cycle %d\n",
> +				ivalue);
> +			return -EINVAL;
> +		}
> +
> +		lirc_rx51->duty_cycle = ivalue;
> +		break;
> +
> +	case LIRC_SET_SEND_CARRIER:
> +		result = get_user(ivalue, (unsigned int *) arg);
> +		if (result)
> +			return result;
> +
> +		if (ivalue > 500000 || ivalue < 20000) {
> +			dev_err(lirc_rx51->dev, ": invalid carrier freq %d\n",
> +				ivalue);
> +			return -EINVAL;
> +		}
> +
> +		lirc_rx51->freq = ivalue;
> +		break;
> +
> +	case LIRC_GET_FEATURES:
> +		result = put_user(LIRC_RX51_DRIVER_FEATURES,
> +				  (unsigned long *) arg);
> +		if (result)
> +			return result;
> +		break;
> +
> +	default:
> +		return -ENOIOCTLCMD;
> +	}
> +
> +	return 0;
> +}
> +
> +static int lirc_rx51_open(struct inode *inode, struct file *file)
> +{
> +	struct lirc_rx51 *lirc_rx51 = lirc_get_pdata(file);
> +	BUG_ON(!lirc_rx51);
> +
> +	file->private_data = lirc_rx51;
> +
> +	if (test_and_set_bit(1, &lirc_rx51->device_is_open))
> +		return -EBUSY;
> +
> +	return lirc_rx51_init_port(lirc_rx51);
> +}
> +
> +static int lirc_rx51_release(struct inode *inode, struct file *file)
> +{
> +	struct lirc_rx51 *lirc_rx51 = file->private_data;
> +
> +	lirc_rx51_free_port(lirc_rx51);
> +
> +	clear_bit(1, &lirc_rx51->device_is_open);
> +
> +	return 0;
> +}
> +
> +static struct lirc_rx51 lirc_rx51 = {
> +	.freq		= 38000,
> +	.duty_cycle	= 50,
> +	.wbuf_index	= -1,
> +};
> +
> +static const struct file_operations lirc_fops = {
> +	.owner		= THIS_MODULE,
> +	.write		= lirc_rx51_write,
> +	.unlocked_ioctl	= lirc_rx51_ioctl,
> +	.read		= lirc_dev_fop_read,
> +	.poll		= lirc_dev_fop_poll,
> +	.open		= lirc_rx51_open,
> +	.release	= lirc_rx51_release,
> +};
> +
> +static struct lirc_driver lirc_rx51_driver = {
> +	.name		= DRIVER_NAME,
> +	.minor		= -1,
> +	.code_length	= 1,
> +	.data		= &lirc_rx51,
> +	.fops		= &lirc_fops,
> +	.owner		= THIS_MODULE,
> +};
> +
> +#ifdef CONFIG_PM
> +
> +static int lirc_rx51_suspend(struct platform_device *dev, pm_message_t state)
> +{
> +	/*
> +	 * In case the device is still open, do not suspend. Normally
> +	 * this should not be a problem as lircd only keeps the device
> +	 * open only for short periods of time. We also don't want to
> +	 * get involved with race conditions that might happen if we
> +	 * were in a middle of a transmit. Thus, we defer any suspend
> +	 * actions until transmit has completed.
> +	 */
> +	if (test_and_set_bit(1, &lirc_rx51.device_is_open))
> +		return -EAGAIN;
> +
> +	clear_bit(1, &lirc_rx51.device_is_open);
> +
> +	return 0;
> +}
> +
> +static int lirc_rx51_resume(struct platform_device *dev)
> +{
> +	return 0;
> +}
> +
> +#else
> +
> +#define lirc_rx51_suspend	NULL
> +#define lirc_rx51_resume	NULL
> +
> +#endif /* CONFIG_PM */
> +
> +static int __devinit lirc_rx51_probe(struct platform_device *dev)
> +{
> +	lirc_rx51_driver.features = LIRC_RX51_DRIVER_FEATURES;
> +	lirc_rx51.pdata = dev->dev.platform_data;
> +	lirc_rx51.pwm_timer_num = lirc_rx51.pdata->pwm_timer;
> +	lirc_rx51.dev = &dev->dev;
> +	lirc_rx51_driver.dev = &dev->dev;
> +	lirc_rx51_driver.minor = lirc_register_driver(&lirc_rx51_driver);
> +	init_waitqueue_head(&lirc_rx51.wqueue);
> +
> +	if (lirc_rx51_driver.minor < 0) {
> +		dev_err(lirc_rx51.dev, ": lirc_register_driver failed: %d\n",
> +		       lirc_rx51_driver.minor);
> +		return lirc_rx51_driver.minor;
> +	}
> +	dev_info(lirc_rx51.dev, "registration ok, minor: %d, pwm: %d\n",
> +		 lirc_rx51_driver.minor, lirc_rx51.pwm_timer_num);
> +
> +	return 0;
> +}
> +
> +static int __exit lirc_rx51_remove(struct platform_device *dev)
> +{
> +	return lirc_unregister_driver(lirc_rx51_driver.minor);
> +}
> +
> +struct platform_driver lirc_rx51_platform_driver = {
> +	.probe		= lirc_rx51_probe,
> +	.remove		= __exit_p(lirc_rx51_remove),
> +	.suspend	= lirc_rx51_suspend,
> +	.resume		= lirc_rx51_resume,
> +	.remove		= __exit_p(lirc_rx51_remove),

.remove is here twice.

> +	.driver		= {
> +		.name	= DRIVER_NAME,
> +		.owner	= THIS_MODULE,
> +	},
> +};
> +
> +static int __init lirc_rx51_init(void)
> +{
> +	return platform_driver_register(&lirc_rx51_platform_driver);
> +}
> +module_init(lirc_rx51_init);
> +
> +static void __exit lirc_rx51_exit(void)
> +{
> +	platform_driver_unregister(&lirc_rx51_platform_driver);
> +}
> +module_exit(lirc_rx51_exit);
> +
> +MODULE_DESCRIPTION("LIRC TX driver for Nokia RX51");
> +MODULE_AUTHOR("Nokia Corporation");
> +MODULE_LICENSE("GPL");
> diff --git a/include/media/ir-rx51.h b/include/media/ir-rx51.h
> new file mode 100644
> index 0000000..104aa89
> --- /dev/null
> +++ b/include/media/ir-rx51.h
> @@ -0,0 +1,10 @@
> +#ifndef _LIRC_RX51_H
> +#define _LIRC_RX51_H
> +
> +struct lirc_rx51_platform_data {
> +	int pwm_timer;
> +
> +	int(*set_max_mpu_wakeup_lat)(struct device *dev, long t);
> +};
> +
> +#endif
> -- 
> 1.7.8.6
> 
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