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Commit 622ecb30 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab
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V4L/DVB (8625): saa7134: Add NEC prococol IR decoding capability 

This patch adds the capability of decoding NEC protocol, received via GPIO18 line.
This GPIO port can trigger saa7134 IRQ.

A future improvement would be to make it a little more generic to work also
with GPIO16 line.

A pure IRQ code didn't work, since some delays were introduced on the tests we
did.

A possible approach would be to use polling at a rate of 2.5 ms or less. If a
new code were taken, a code similar to nec_task() could be used. However, this
would add an extra overhead to kernel, and will consume more power.

Due to that, we took an hybrid approach: an IRQ upper half to trigger when a
new key is received and a bottom half to convert pulse-distance into a keycode.

The bottom half is polling based, to improve performance. During the bottom
half proccess, GPIO18 IRQ line is disabled, preventing IRQ reentrancy and
improving performance a little bit.

Thanks to Sistema Fenix (http://www.sistemafenix.com.br/

) for sponsoring this
development.

Signed-off-by: default avatarGilberto <gilberto@sistemafenix.com.br>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent d56dc612

drivers/media/video/saa7134/saa7134-input.c

+134 −6
Original line number Diff line number Diff line
@@ -62,8 +62,11 @@ MODULE_PARM_DESC(disable_other_ir, "disable full codes of " 
#define i2cdprintk(fmt, arg...)    if (ir_debug) \

	printk(KERN_DEBUG "%s/ir: " fmt, ir->c.name , ## arg)



/** rc5 functions */

/* Helper functions for RC5 and NEC decoding at GPIO16 or GPIO18 */

static int saa7134_rc5_irq(struct saa7134_dev *dev);

static int saa7134_nec_irq(struct saa7134_dev *dev);

static void nec_task(unsigned long data);

static void saa7134_nec_timer(unsigned long data);



/* -------------------- GPIO generic keycode builder -------------------- */
@@ -280,7 +283,9 @@ void saa7134_input_irq(struct saa7134_dev *dev) 
{

	struct card_ir *ir = dev->remote;



	if (!ir->polling && !ir->rc5_gpio) {

	if (ir->nec_gpio) {

		saa7134_nec_irq(dev);

	} else if (!ir->polling && !ir->rc5_gpio) {

		build_key(dev);

	} else if (ir->rc5_gpio) {

		saa7134_rc5_irq(dev);
@@ -316,6 +321,10 @@ void saa7134_ir_start(struct saa7134_dev *dev, struct card_ir *ir) 
		ir->addr = 0x17;

		ir->rc5_key_timeout = ir_rc5_key_timeout;

		ir->rc5_remote_gap = ir_rc5_remote_gap;

	} else if (ir->nec_gpio) {

		setup_timer(&ir->timer_keyup, saa7134_nec_timer,

			    (unsigned long)dev);

		tasklet_init(&ir->tlet, nec_task, (unsigned long)dev);

	}

}
@@ -335,6 +344,7 @@ int saa7134_input_init1(struct saa7134_dev *dev) 
	u32 mask_keyup   = 0;

	int polling      = 0;

	int rc5_gpio	 = 0;

	int nec_gpio	 = 0;

	int ir_type      = IR_TYPE_OTHER;

	int err;
@@ -533,6 +543,7 @@ int saa7134_input_init1(struct saa7134_dev *dev) 
	ir->mask_keyup   = mask_keyup;

	ir->polling      = polling;

	ir->rc5_gpio	 = rc5_gpio;

	ir->nec_gpio	 = nec_gpio;



	/* init input device */

	snprintf(ir->name, sizeof(ir->name), "saa7134 IR (%s)",
@@ -675,8 +686,125 @@ static int saa7134_rc5_irq(struct saa7134_dev *dev) 
	return 1;

}



/* ----------------------------------------------------------------------

 * Local variables:

 * c-basic-offset: 8

 * End:



/* On NEC protocol, One has 2.25 ms, and zero has 1.125 ms

   The first pulse (start) has 9 + 4.5 ms

 */



static void saa7134_nec_timer(unsigned long data)

{

	struct saa7134_dev *dev = (struct saa7134_dev *) data;

	struct card_ir *ir = dev->remote;



	dprintk("Cancel key repeat\n");



	ir_input_nokey(ir->dev, &ir->ir);

}



static void nec_task(unsigned long data)

{

	struct saa7134_dev *dev = (struct saa7134_dev *) data;

	struct card_ir *ir;

	struct timeval tv;

	int count, pulse, oldpulse, gap;

	u32 ircode = 0, not_code = 0;

	int ngap = 0;



	if (!data) {

		printk(KERN_ERR "saa713x/ir: Can't recover dev struct\n");

		/* GPIO will be kept disabled */

		return;

	}



	ir = dev->remote;



	/* rising SAA7134_GPIO_GPRESCAN reads the status */

	saa_clearb(SAA7134_GPIO_GPMODE3, SAA7134_GPIO_GPRESCAN);

	saa_setb(SAA7134_GPIO_GPMODE3, SAA7134_GPIO_GPRESCAN);



	oldpulse = saa_readl(SAA7134_GPIO_GPSTATUS0 >> 2) & ir->mask_keydown;

	pulse = oldpulse;



	do_gettimeofday(&tv);

	ir->base_time = tv;



	/* Decode NEC pulsecode. This code can take up to 76.5 ms to run.

	   Unfortunately, using IRQ to decode pulse didn't work, since it uses

	   a pulse train of 38KHz. This means one pulse on each 52 us

	 */

	do {

		/* Wait until the end of pulse/space or 5 ms */

		for (count = 0; count < 500; count++)  {

			udelay(10);

			/* rising SAA7134_GPIO_GPRESCAN reads the status */

			saa_clearb(SAA7134_GPIO_GPMODE3, SAA7134_GPIO_GPRESCAN);

			saa_setb(SAA7134_GPIO_GPMODE3, SAA7134_GPIO_GPRESCAN);

			pulse = saa_readl(SAA7134_GPIO_GPSTATUS0 >> 2)

				& ir->mask_keydown;

			if (pulse != oldpulse)

				break;

		}



		do_gettimeofday(&tv);

		gap = 1000000 * (tv.tv_sec - ir->base_time.tv_sec) +

				tv.tv_usec - ir->base_time.tv_usec;



		if (!pulse) {

			/* Bit 0 has 560 us, while bit 1 has 1120 us.

			   Do something only if bit == 1

			 */

			if (ngap && (gap > 560 + 280)) {

				unsigned int shift = ngap - 1;



				/* Address first, then command */

				if (shift < 8) {

					shift += 8;

					ircode |= 1 << shift;

				} else if (shift < 16) {

					not_code |= 1 << shift;

				} else if (shift < 24) {

					shift -= 16;

					ircode |= 1 << shift;

				} else {

					shift -= 24;

					not_code |= 1 << shift;

				}

			}

			ngap++;

		}





		ir->base_time = tv;



		/* TIMEOUT - Long pulse */

		if (gap >= 5000)

			break;

		oldpulse = pulse;

	} while (ngap < 32);



	if (ngap == 32) {

		/* FIXME: should check if not_code == ~ircode */

		ir->code = ir_extract_bits(ircode, ir->mask_keycode);



		dprintk("scancode = 0x%02x (code = 0x%02x, notcode= 0x%02x)\n",

			 ir->code, ircode, not_code);



		ir_input_keydown(ir->dev, &ir->ir, ir->code, ir->code);

	} else

		dprintk("Repeat last key\n");



	/* Keep repeating the last key */

	mod_timer(&ir->timer_keyup, jiffies + msecs_to_jiffies(150));



	saa_setl(SAA7134_IRQ2, SAA7134_IRQ2_INTE_GPIO18);

}



static int saa7134_nec_irq(struct saa7134_dev *dev)

{

	struct card_ir *ir = dev->remote;



	saa_clearl(SAA7134_IRQ2, SAA7134_IRQ2_INTE_GPIO18);

	tasklet_schedule(&ir->tlet);



	return 1;

}

include/media/ir-common.h

+5 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 


#include <linux/input.h>

#include <linux/workqueue.h>

#include <linux/interrupt.h>



#define IR_TYPE_RC5     1

#define IR_TYPE_PD      2 /* Pulse distance encoded IR */
@@ -85,6 +86,10 @@ struct card_ir { 
	u32 code;			/* raw code under construction */

	struct timeval base_time;	/* time of last seen code */

	int active;			/* building raw code */



	/* NEC decoding */

	u32			nec_gpio;

	struct tasklet_struct   tlet;

};



void ir_input_init(struct input_dev *dev, struct ir_input_state *ir,