Re: [PATCH] leds: ti-lmu-common: Fix coccinelle issue in TI LMU

From: Dan Murphy
Date: Tue Aug 27 2019 - 09:37:22 EST


On 8/26/19 2:34 PM, Jacek Anaszewski wrote:

On 8/26/19 4:53 PM, Dan Murphy wrote:

On 8/24/19 10:18 AM, Jacek Anaszewski wrote:
Hi Dan,

Thank you for the patch.

On 8/23/19 9:55 PM, Dan Murphy wrote:
Fix the coccinelle issues found in the TI LMU common code

drivers/leds/leds-ti-lmu-common.c:97:20-29: WARNING: Unsigned
expression compared with zero: ramp_down < 0
drivers/leds/leds-ti-lmu-common.c:97:5-12: WARNING: Unsigned
expression compared with zero: ramp_up < 0
Wouldn't it make more sense to remove those pointless checks?
Clearly a correct index of an array cannot be negative.
Looking at the code I would make more int -> unsigned int conversions:

- ramp_table should be unsigned int
- ti_lmu_common_convert_ramp_to_index should return unsigned int

Yeah I was going to just remove the code but when I was writing the
original code my intent was

to extend the ramp call to allow other TI LMU driver to pass in the
device specific ramp table.

But since I don't currently have any devices on my plate that require
that I can just remove the code as well
You don't need to remove, just do the conversions I proposed.
Unless it introduces some other problems I am currently not aware of.

Well just converting those two would/did not fix the issue.

But actually there is only 1 possibility that could happen if the convert function returns -EINVAL

So the check should be

if (ramp_up == -EINVAL || ramp_down == -EINVAL)

Because ramp_up/down should never be less then zero otherwise.