linux-kernel - Re: [PATCH] [media] ir-spi: Fix issues with lirc API

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Date:   Tue, 13 Jun 2017 12:57:43 +0900
From:   Andi Shyti <andi.shyti@...sung.com>
To:     Anton Blanchard <anton@...abs.org>
Cc:     mchehab@...nel.org, sean@...s.org, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [media] ir-spi: Fix issues with lirc API

Hi Anton,

On Sun, May 07, 2017 at 11:00:11AM +1000, Anton Blanchard wrote:
> From: Anton Blanchard <anton@...ba.org>
> 
> The ir-spi driver has 2 issues which prevents it from working with
> lirc:
> 
> 1. The ir-spi driver uses 16 bits of SPI data to create one cycle of
> the waveform. As such our SPI clock needs to be 16x faster than the
> carrier frequency.
> 
> The driver is inconsistent in how it currently handles this. It
> initializes it to the carrier frequency:
> 
> But the commit message has some example code which initialises it
> to 16x the carrier frequency:
> 
> 	val = 608000;
> 	ret = ioctl(fd, LIRC_SET_SEND_CARRIER, &val);
> 
> To maintain compatibility with lirc, always do the frequency adjustment
> in the driver.
> 
> 2. lirc presents pulses in microseconds, but the ir-spi driver treats
> them as cycles of the carrier. Similar to other lirc drivers, do the
> conversion with DIV_ROUND_CLOSEST().
> 
> Fixes: fe052da49201 ("[media] rc: add support for IR LEDs driven through SPI")
> Cc: stable@...r.kernel.org
> Signed-off-by: Anton Blanchard <anton@...ba.org>

Thanks for fixing it.

Reviewed-by: Andi Shyti <andi.shyti@...sung.com>

Andi