linux-kernel - Re: [PATCH] HID: appleir: add support for Apple ir devices

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Message-ID: <alpine.LNX.2.00.1304092155330.17280@pobox.suse.cz>
Date:	Tue, 9 Apr 2013 22:10:34 +0200 (CEST)
From:	Jiri Kosina <jkosina@...e.cz>
To:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
Cc:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Benjamin Tissoires <benjamin.tissoires@...il.com>,
	Bastien Nocera <hadess@...ess.net>,
	Fabien <fabien.andre@...il.com>, Jarod Wilson <jarod@...hat.com>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] HID: appleir: add support for Apple ir devices

On Mon, 8 Apr 2013, Benjamin Tissoires wrote:

> This driver was originally written by James McKenzie, updated by
> Greg Kroah-Hartman, further updated by Bastien Nocera, with suspend
> support added.
> I ported it to the HID subsystem, in order to simplify it a litle
> and allow lirc to use it through hiddev.
> 
> More recent versions of the IR receiver are also supported through
> a patch by Alex Karpenko. The patch also adds support for the 2nd
> and 5th generation of the controller, and the menu key on newer
> brushed metal remotes.
> 
> Tested-by: Fabien André <fabien.andre@...il.com>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>
> ---
> Hi guys,
> 
> this is the re-spin of Bastien's patch submitted last november.
> I ported it to use the hid subsystem, reducing the size of the driver
> to 355 lines instead of 527.

Thanks. Generally, I like the idea of appleir being on the hid bus.

Bastien, could you please provide your Ack (and most importantly also 
Tested-by?).

[ ... snip ... ]
> +static void dump_packet(struct appleir *appleir, char *msg, u8 *data, int len)
> +{
> +	appleir_dbg(appleir->hid,
> +		    "appleir: %s (%d bytes) %*ph (should be command %d)\n",
> +		    msg, len, len, data, (data[4] >> 1) & KEY_MASK);
> +}

Can't we just use HID debugfs interface for this kind of debugging output?

> +static int get_key(int data)
> +{
> +	/*
> +	 * The indexes of the keys are computed like this:
> +	 * 0x00 or 0x01 (        )	key:   0	-> KEY_RESERVED
> +	 * 0x02 or 0x03 (  menu  )	key:   1	-> KEY_MENU
> +	 * 0x04 or 0x05 (   >"   )	key:   2	-> KEY_PLAYPAUSE
> +	 * 0x06 or 0x07 (   >>   )	key:   3	-> KEY_FORWARD
> +	 * 0x08 or 0x09 (   <<   )	key:   4	-> KEY_BACK
> +	 * 0x0a or 0x0b (    +   )	key:   5	-> KEY_VOLUMEUP
> +	 * 0x0c or 0x0d (    -   )	key:   6	-> KEY_VOLUMEDOWN
> +	 * 0x0e or 0x0f (        )	key:   7	-> KEY_RESERVED
> +	 * 0x50 or 0x51 (        )	key:  -8	-> KEY_RESERVED
> +	 * 0x52 or 0x53 (        )	key:  -9	-> KEY_RESERVED
> +	 * 0x54 or 0x55 (        )	key: -10	-> KEY_RESERVED
> +	 * 0x56 or 0x57 (        )	key: -11	-> KEY_RESERVED
> +	 * 0x58 or 0x59 (        )	key: -12	-> KEY_RESERVED
> +	 * 0x5a or 0x5b (        )	key: -13	-> KEY_RESERVED
> +	 * 0x5c or 0x5d ( middle )	key: -14	-> KEY_ENTER
> +	 * 0x5e or 0x5f (   >"   )	key: -15	-> KEY_PLAYPAUSE
> +	 */
> +	int key = (data >> 1) & KEY_MASK;
> +
> +	if ((data & TWO_PACKETS_MASK))
> +		/* Part of a 2 packet-command */
> +		key = -key;

I think all the shuffling with negative indices would justify an 
explanatory comment; it's quite confusing on a first sight.

[ ... snip ... ]
> +static int appleir_raw_event(struct hid_device *hid, struct hid_report *report,
> +	 u8 *data, int len)
> +{
> +	struct appleir *appleir = hid_get_drvdata(hid);
> +	static const u8 keydown[] = { 0x25, 0x87, 0xee };
> +	static const u8 keyrepeat[] = { 0x26, };
> +	static const u8 flatbattery[] = { 0x25, 0x87, 0xe0 };
> +	unsigned long flags;
> +
> +	if (debug)
> +		dump_packet(appleir, "received", data, len);
> +
> +	if (len != 5)
> +		goto out;
> +
> +	if (!memcmp(data, keydown, sizeof(keydown))) {
> +		int index;
> +
> +		spin_lock_irqsave(&appleir->lock, flags);
> +		/* If we already have a key down, take it up before marking
> +		   this one down */

Could you please make this comment in-line with kernel comments coding 
style?

Thanks, Benjamin.

-- 
Jiri Kosina
SUSE Labs
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