drm/ssd130x: Silence a `dubious: x & !y` warning

The sparse tool complains with the following warning:

$ make M=drivers/gpu/drm/solomon/ C=2
  CC [M]  drivers/gpu/drm/solomon/ssd130x.o
  CHECK   drivers/gpu/drm/solomon/ssd130x.c
drivers/gpu/drm/solomon/ssd130x.c:363:21: warning: dubious: x & !y

This seems to be a false positive in my opinion but still we can silence
the tool while making the code easier to read. Let's also add a comment,
to explain why the "com_seq" logical not is used rather than its value.

Reported-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230121190930.2804224-1-javierm@redhat.com
This commit is contained in:
Javier Martinez Canillas 2023-01-21 20:09:30 +01:00
parent 998101f2a7
commit 51affef35b
No known key found for this signature in database
GPG Key ID: C751E590D63F3D69
1 changed files with 9 additions and 2 deletions

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@ -81,7 +81,7 @@
#define SSD130X_SET_PRECHARGE_PERIOD2_MASK GENMASK(7, 4)
#define SSD130X_SET_PRECHARGE_PERIOD2_SET(val) FIELD_PREP(SSD130X_SET_PRECHARGE_PERIOD2_MASK, (val))
#define SSD130X_SET_COM_PINS_CONFIG1_MASK GENMASK(4, 4)
#define SSD130X_SET_COM_PINS_CONFIG1_SET(val) FIELD_PREP(SSD130X_SET_COM_PINS_CONFIG1_MASK, !(val))
#define SSD130X_SET_COM_PINS_CONFIG1_SET(val) FIELD_PREP(SSD130X_SET_COM_PINS_CONFIG1_MASK, (val))
#define SSD130X_SET_COM_PINS_CONFIG2_MASK GENMASK(5, 5)
#define SSD130X_SET_COM_PINS_CONFIG2_SET(val) FIELD_PREP(SSD130X_SET_COM_PINS_CONFIG2_MASK, (val))
@ -298,6 +298,7 @@ static void ssd130x_power_off(struct ssd130x_device *ssd130x)
static int ssd130x_init(struct ssd130x_device *ssd130x)
{
u32 precharge, dclk, com_invdir, compins, chargepump, seg_remap;
bool scan_mode;
int ret;
/* Set initial contrast */
@ -360,7 +361,13 @@ static int ssd130x_init(struct ssd130x_device *ssd130x)
/* Set COM pins configuration */
compins = BIT(1);
compins |= (SSD130X_SET_COM_PINS_CONFIG1_SET(ssd130x->com_seq) |
/*
* The COM scan mode field values are the inverse of the boolean DT
* property "solomon,com-seq". The value 0b means scan from COM0 to
* COM[N - 1] while 1b means scan from COM[N - 1] to COM0.
*/
scan_mode = !ssd130x->com_seq;
compins |= (SSD130X_SET_COM_PINS_CONFIG1_SET(scan_mode) |
SSD130X_SET_COM_PINS_CONFIG2_SET(ssd130x->com_lrremap));
ret = ssd130x_write_cmd(ssd130x, 2, SSD130X_SET_COM_PINS_CONFIG, compins);
if (ret < 0)