Re: [PATCH 2/2] media: rc: add driver for IR remote receiver on MT7623 SoC
From: Sean Wang <hidden>
Date: 2017-01-09 03:13:32
Also in:
linux-arm-kernel, linux-media, linux-mediatek, lkml
On Sun, 2017-01-08 at 21:16 +0000, Sean Young wrote:
Hi Sean, On Fri, Jan 06, 2017 at 03:31:25PM +0800, Sean Wang wrote:quoted
On Thu, 2017-01-05 at 17:12 +0000, Sean Young wrote:quoted
On Fri, Jan 06, 2017 at 12:06:24AM +0800, sean.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org wrote:quoted
+ /* Handle pulse and space until end of message */ + for (i = 0 ; i < MTK_CHKDATA_SZ ; i++) { + val = mtk_r32(ir, MTK_CHKDATA_REG(i)); + dev_dbg(ir->dev, "@reg%d=0x%08x\n", i, val); + + for (j = 0 ; j < 4 ; j++) { + wid = (val & (0xff << j * 8)) >> j * 8; + rawir.pulse = !rawir.pulse; + rawir.duration = wid * (MTK_IR_SAMPLE + 1); + ir_raw_event_store_with_filter(ir->rc, &rawir); + + if (MTK_IR_END(wid)) + goto end_msg; + } + }If I read this correctly, there is a maximum of 17 * 4 = 68 edges per IR message. The rc6 mce key 0 (scancode 0x800f0400) is 69 edges, so that won't work.Uh, this is related to hardware limitation. Maximum number hardware holds indeed is only 68 edges as you said :( For the case, I will try change the logic into that the whole message is dropped if no end of message is seen within 68 counts to avoid wasting CPU for decoding.I'm not sure it is worthwhile dropping the IR in that case. The processing is minimal and it might be possible that we have just enough IR to decode a scancode even if the trailing end of message is missing. Note that the call to ir_raw_event_set_idle() will generate an timeout IR event, so there will always be an end of message marker.
1) I agree with you :) The original logic I made already as you pointed out is sent incomplete IR message to let ir-raw try to decode as possible. 2) I had another question. I found multiple and same IR messages being received when using SONY remote controller. Should driver needs to report each message or only one of these to the upper layer ?
All I wanted to do was point out a limitation in case there is a workaround; if there is not then we might as well make do with the IR we do have.
I also will leave some words about limitation we had in the comments.
Thanks Sean
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