From: Javier Martinez Canillas Date: Sat, 21 Jan 2023 19:09:30 +0000 (+0100) Subject: drm/ssd130x: Silence a `dubious: x & !y` warning X-Git-Tag: v6.6.17~3937^2~23^2~849 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=51affef35bb39f186aef7eeeb4a7f9ceccd3e65e;p=platform%2Fkernel%2Flinux-rpi.git 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 Signed-off-by: Javier Martinez Canillas Reviewed-by: Thomas Zimmermann Link: https://patchwork.freedesktop.org/patch/msgid/20230121190930.2804224-1-javierm@redhat.com --- diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c index c3bf3a1..b16330a 100644 --- a/drivers/gpu/drm/solomon/ssd130x.c +++ b/drivers/gpu/drm/solomon/ssd130x.c @@ -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)