Re: [PATCH 06/11] media: rc: img-ir: add NEC decoder module

[Mauro Carvalho Chehab <m.chehab@samsung.com>]

Em Fri, 13 Dec 2013 15:12:54 +0000
James Hogan <james.hogan@imgtec.com> escreveu:

> Add an img-ir module for decoding the NEC and extended NEC infrared
> protocols.
> 
> Signed-off-by: James Hogan <james.hogan@imgtec.com>
> Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
> Cc: linux-media@vger.kernel.org
> ---
>  drivers/media/rc/img-ir/Kconfig      |   7 ++
>  drivers/media/rc/img-ir/Makefile     |   1 +
>  drivers/media/rc/img-ir/img-ir-nec.c | 149 +++++++++++++++++++++++++++++++++++
>  3 files changed, 157 insertions(+)
>  create mode 100644 drivers/media/rc/img-ir/img-ir-nec.c
> 
> diff --git a/drivers/media/rc/img-ir/Kconfig b/drivers/media/rc/img-ir/Kconfig
> index 60eaba6a0843..44d00227c6c4 100644
> --- a/drivers/media/rc/img-ir/Kconfig
> +++ b/drivers/media/rc/img-ir/Kconfig
> @@ -24,3 +24,10 @@ config IR_IMG_HW
>  	   signals in hardware. This is more reliable, consumes less processing
>  	   power since only a single interrupt is received for each scancode,
>  	   and allows an IR scancode to be used as a wake event.
> +
> +config IR_IMG_NEC
> +	tristate "NEC protocol support"
> +	depends on IR_IMG && IR_IMG_HW
> +	help
> +	   Say Y or M here to enable support for the NEC and extended NEC
> +	   protocols in the ImgTec infrared decoder block.
> diff --git a/drivers/media/rc/img-ir/Makefile b/drivers/media/rc/img-ir/Makefile
> index 4ef86edec873..f3052878f092 100644
> --- a/drivers/media/rc/img-ir/Makefile
> +++ b/drivers/media/rc/img-ir/Makefile
> @@ -4,3 +4,4 @@ img-ir-$(CONFIG_IR_IMG_HW)	+= img-ir-hw.o
>  img-ir-objs			:= $(img-ir-y)
>  
>  obj-$(CONFIG_IR_IMG)		+= img-ir.o
> +obj-$(CONFIG_IR_IMG_NEC)	+= img-ir-nec.o
> diff --git a/drivers/media/rc/img-ir/img-ir-nec.c b/drivers/media/rc/img-ir/img-ir-nec.c
> new file mode 100644
> index 000000000000..ba376caafaf2
> --- /dev/null
> +++ b/drivers/media/rc/img-ir/img-ir-nec.c
> @@ -0,0 +1,149 @@
> +/*
> + * ImgTec IR Decoder setup for NEC protocol.
> + *
> + * Copyright 2010-2013 Imagination Technologies Ltd.
> + */
> +
> +#include <linux/module.h>
> +
> +#include "img-ir-hw.h"
> +
> +/* Convert NEC data to a scancode */
> +static int img_ir_nec_scancode(int len, u64 raw, u64 protocols)
> +{
> +	unsigned int addr, addr_inv, data, data_inv;
> +	int scancode;
> +	/* a repeat code has no data */
> +	if (!len)
> +		return IMG_IR_REPEATCODE;
> +	if (len != 32)
> +		return IMG_IR_ERR_INVALID;
> +	addr     = (raw >>  0) & 0xff;
> +	addr_inv = (raw >>  8) & 0xff;
> +	data     = (raw >> 16) & 0xff;
> +	data_inv = (raw >> 24) & 0xff;
> +	/* Validate data */
> +	if ((data_inv ^ data) != 0xff)
> +		return IMG_IR_ERR_INVALID;
> +
> +	if ((addr_inv ^ addr) != 0xff) {
> +		/* Extended NEC */
> +		scancode = addr     << 16 |
> +			   addr_inv <<  8 |
> +			   data;
> +	} else {
> +		/* Normal NEC */
> +		scancode = addr << 8 |
> +			   data;
> +	}

There are some types of NEC extended that uses the full 32 bits as
scancodes. Those are used at least on Apple and TiVo remote controllers.

> +	return scancode;
> +}
> +
> +/* Convert NEC scancode to NEC data filter */
> +static int img_ir_nec_filter(const struct img_ir_sc_filter *in,
> +			     struct img_ir_filter *out, u64 protocols)
> +{
> +	unsigned int addr, addr_inv, data, data_inv;
> +	unsigned int addr_m, addr_inv_m, data_m;
> +
> +	data     = in->data & 0xff;
> +	data_m   = in->mask & 0xff;
> +	data_inv = data ^ 0xff;
> +
> +	if (in->data & 0xff000000)
> +		return -EINVAL;
> +
> +	if (in->data & 0x00ff0000) {
> +		/* Extended NEC */
> +		addr       = (in->data >> 16) & 0xff;
> +		addr_m     = (in->mask >> 16) & 0xff;
> +		addr_inv   = (in->data >>  8) & 0xff;
> +		addr_inv_m = (in->mask >>  8) & 0xff;
> +	} else {
> +		/* Normal NEC */
> +		addr       = (in->data >>  8) & 0xff;
> +		addr_m     = (in->mask >>  8) & 0xff;
> +		addr_inv   = addr ^ 0xff;
> +		addr_inv_m = addr_m;
> +	}
> +
> +	out->data = data_inv << 24 |
> +		    data     << 16 |
> +		    addr_inv <<  8 |
> +		    addr;
> +	out->mask = data_m     << 24 |
> +		    data_m     << 16 |
> +		    addr_inv_m <<  8 |
> +		    addr_m;
> +	return 0;
> +}
> +
> +/*
> + * NEC decoder
> + * See also http://www.sbprojects.com/knowledge/ir/nec.php
> + *        http://wiki.altium.com/display/ADOH/NEC+Infrared+Transmission+Protocol
> + */
> +static struct img_ir_decoder img_ir_nec = {
> +	.type = RC_BIT_NEC,
> +	.control = {
> +		.decoden = 1,
> +		.code_type = IMG_IR_CODETYPE_PULSEDIST,
> +	},
> +	/* main timings */
> +	.unit = 562500, /* 562.5 us */
> +	.timings = {
> +		/* leader symbol */
> +		.ldr = {
> +			.pulse = { 16	/* 9ms */ },
> +			.space = { 8	/* 4.5ms */ },
> +		},
> +		/* 0 symbol */
> +		.s00 = {
> +			.pulse = { 1	/* 562.5 us */ },
> +			.space = { 1	/* 562.5 us */ },
> +		},
> +		/* 1 symbol */
> +		.s01 = {
> +			.pulse = { 1	/* 562.5 us */ },
> +			.space = { 3	/* 1687.5 us */ },
> +		},
> +		/* free time */
> +		.ft = {
> +			.minlen = 32,
> +			.maxlen = 32,
> +			.ft_min = 10,	/* 5.625 ms */
> +		},
> +	},
> +	/* repeat codes */
> +	.repeat = 108,			/* 108 ms */
> +	.rtimings = {
> +		/* leader symbol */
> +		.ldr = {
> +			.space = { 4	/* 2.25 ms */ },
> +		},
> +		/* free time */
> +		.ft = {
> +			.minlen = 0,	/* repeat code has no data */
> +			.maxlen = 0,
> +		},
> +	},
> +	/* scancode logic */
> +	.scancode = img_ir_nec_scancode,
> +	.filter = img_ir_nec_filter,
> +};
> +
> +static int __init img_ir_nec_init(void)
> +{
> +	return img_ir_register_decoder(&img_ir_nec);
> +}
> +module_init(img_ir_nec_init);
> +
> +static void __exit img_ir_nec_exit(void)
> +{
> +	img_ir_unregister_decoder(&img_ir_nec);
> +}
> +module_exit(img_ir_nec_exit);
> +
> +MODULE_AUTHOR("Imagination Technologies Ltd.");
> +MODULE_DESCRIPTION("ImgTec IR NEC protocol support");
> +MODULE_LICENSE("GPL");


-- 

Cheers,
Mauro