Re: [PATCH] OMAP: Add keypad driver

On Fri, Jan 08, 2016 at 02:41:00AM +0100, Janusz Krzysztofik wrote:

On Thu, 7 Jan 2016 15:22:28 Dmitry Torokhov wrote:

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On Thu, Jan 07, 2016 at 12:13:17PM -0800, Tony Lindgren wrote:

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* Dmitry Torokhov [off-list ref] [160107 10:54]:

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On Thu, Jan 7, 2016 at 1:37 AM, Dan Carpenter 

[off-list ref] wrote:

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...

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   157                          key = 

keycodes[MATRIX_SCAN_CODE(row, col, row_shift)];

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   158                          if (key < 0) {
                                    ^^^^^^^
Never true.  Not sure what was intended.

It looks like this check was broken by
da1f026b532ce944d74461497dc6d8c16456466e (Keyboard: omap-keypad: 

use

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matrix_keypad.h). Previously the driver would expect a list of 

known

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keys and would scan it and return -1 if key was not found. Now we 

have

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2 options:

1. Simply remove the check
2. Change the condition to "if (key == KEY_RESERVED)"

I do not really have preference. Tony?

Sounds like the check is not needed if it has not been used for
past five years, so my preference is option #1 then.

OK, how about the below then?

--
Dmitry


Input: omap-keypad - remove dead check

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Commit da1f026b532ce944d74461497dc6d8c16456466e ("Keyboard:
omap-keypad: use matrix_keypad.h") switched the driver to use matrix
keypad infrastructure, which made array of keycodes to be unsigned
short, and caused the test for negativity never trigger. This leads
to the following> 
static checker warning:
        drivers/input/keyboard/omap-keypad.c:158 omap_kp_tasklet()
        warn: 'keycodes[]' is never negative.

Given that we did not care about this check for a few years already
let's simply remove it.

Reported-by: Dan Carpenter <redacted>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---

 drivers/input/keyboard/omap-keypad.c |    8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/input/keyboard/omap-keypad.c

b/drivers/input/keyboard/omap-keypad.c index 75ad666..e0d72c8 100644

--- a/drivers/input/keyboard/omap-keypad.c
+++ b/drivers/input/keyboard/omap-keypad.c

@@ -155,14 +155,6 @@ static void omap_kp_tasklet(unsigned long data) 
                               "pressed" : "released");  
 #else  
                        key = keycodes[MATRIX_SCAN_CODE(row, col, 

row_shift)]; 

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-                       if (key < 0) {
-                               printk(KERN_WARNING
-                                     "omap-keypad: Spurious key event 

%d-%d\n",

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-                                      col, row);
-                               /* We scan again after a couple of 

seconds */

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-                               spurious = 1;

Hi,

That code was written before I played with it so I'm not really sure 
about its purpose, but it looks to me like something intended as a 
debouncer.

Since that was the only place where the spurious variable could be 
modified, I think we should also remove the now unreachable code that 
manipulates delay based on spurious value several lines below, as well 
as declaration and initialization of spurious at the beginning of 
omap_kp_tasklet().

Yeah, now that I look at it this driver needs some love. The probing is
racy, remove is incomplete, etc.

Do any of you guys have hardware that uses it?

Thanks.

-- 
Dmitry