drm/i915: Move abs_diff() to math.h

abs_diff() belongs to math.h.  Move it there.  This will allow others to
use it.

[andriy.shevchenko@linux.intel.com: add abs_diff() documentation]
Link: https://lkml.kernel.org/r/20230804050934.83223-1-andriy.shevchenko@linux.intel.com
[akpm@linux-foundation.org: fix comment, per Randy]
Link: https://lkml.kernel.org/r/20230803131918.53727-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org> # tty/serial
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> # gpu/ipu-v3
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
index 6b2d8a1..290e856 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
+++ b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
@@ -21,6 +21,7 @@
  * DEALINGS IN THE SOFTWARE.
  */
 
+#include <linux/math.h>
 #include <linux/string_helpers.h>
 
 #include "i915_reg.h"

diff --git a/drivers/gpu/drm/i915/display/intel_dpll_mgr.h b/drivers/gpu/drm/i915/display/intel_dpll_mgr.h
index ba62eb5..04e6810 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dpll_mgr.h
+++ b/drivers/gpu/drm/i915/display/intel_dpll_mgr.h
@@ -29,13 +29,6 @@
 
 #include "intel_wakeref.h"
 
-/*FIXME: Move this to a more appropriate place. */
-#define abs_diff(a, b) ({                      \
-       typeof(a) __a = (a);                    \
-       typeof(b) __b = (b);                    \
-       (void) (&__a == &__b);                  \
-       __a > __b ? (__a - __b) : (__b - __a); })
-
 enum tc_port;
 struct drm_i915_private;
 struct intel_atomic_state;

diff --git a/drivers/gpu/ipu-v3/ipu-image-convert.c b/drivers/gpu/ipu-v3/ipu-image-convert.c
index af16120..8413165 100644 (file)
--- a/drivers/gpu/ipu-v3/ipu-image-convert.c
+++ b/drivers/gpu/ipu-v3/ipu-image-convert.c
@@ -7,7 +7,10 @@
 
 #include <linux/interrupt.h>
 #include <linux/dma-mapping.h>
+#include <linux/math.h>
+
 #include <video/imx-ipu-image-convert.h>
+
 #include "ipu-prv.h"
 
 /*
@@ -543,7 +546,7 @@ static void find_best_seam(struct ipu_image_convert_ctx *ctx,
                unsigned int in_pos;
                unsigned int in_pos_aligned;
                unsigned int in_pos_rounded;
-               unsigned int abs_diff;
+               unsigned int diff;
 
                /*
                 * Tiles in the right row / bottom column may not be allowed to
@@ -575,15 +578,11 @@ static void find_best_seam(struct ipu_image_convert_ctx *ctx,
                    (in_edge - in_pos_rounded) % in_burst)
                        continue;
 
-               if (in_pos < in_pos_aligned)
-                       abs_diff = in_pos_aligned - in_pos;
-               else
-                       abs_diff = in_pos - in_pos_aligned;
-
-               if (abs_diff < min_diff) {
+               diff = abs_diff(in_pos, in_pos_aligned);
+               if (diff < min_diff) {
                        in_seam = in_pos_rounded;
                        out_seam = out_pos;
-                       min_diff = abs_diff;
+                       min_diff = diff;
                }
        }
 

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 82d35db..9be63a1 100644 (file)
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -222,16 +222,11 @@ static inline int calculate_baud_abs_diff(struct uart_port *port,
                                unsigned int baud, unsigned int mode)
 {
        unsigned int n = port->uartclk / (mode * baud);
-       int abs_diff;
 
        if (n == 0)
                n = 1;
 
-       abs_diff = baud - (port->uartclk / (mode * n));
-       if (abs_diff < 0)
-               abs_diff = -abs_diff;
-
-       return abs_diff;
+       return abs_diff(baud, port->uartclk / (mode * n));
 }
 
 /*

diff --git a/drivers/video/fbdev/core/svgalib.c b/drivers/video/fbdev/core/svgalib.c
index 9e01322..2cba158 100644 (file)
--- a/drivers/video/fbdev/core/svgalib.c
+++ b/drivers/video/fbdev/core/svgalib.c
@@ -14,6 +14,7 @@
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/fb.h>
+#include <linux/math.h>
 #include <linux/svga.h>
 #include <asm/types.h>
 #include <asm/io.h>
@@ -372,12 +373,6 @@ EXPORT_SYMBOL(svga_get_caps);
  *  F_VCO = (F_BASE * M) / N
  *  F_OUT = F_VCO / (2^R)
  */
-
-static inline u32 abs_diff(u32 a, u32 b)
-{
-       return (a > b) ? (a - b) : (b - a);
-}
-
 int svga_compute_pll(const struct svga_pll *pll, u32 f_wanted, u16 *m, u16 *n, u16 *r, int node)
 {
        u16 am, an, ar;

diff --git a/include/linux/math.h b/include/linux/math.h
index 2d38865..dd41527 100644 (file)
--- a/include/linux/math.h
+++ b/include/linux/math.h
@@ -156,6 +156,25 @@ __STRUCT_FRACT(u32)
        ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
 
 /**
+ * abs_diff - return absolute value of the difference between the arguments
+ * @a: the first argument
+ * @b: the second argument
+ *
+ * @a and @b have to be of the same type. With this restriction we compare
+ * signed to signed and unsigned to unsigned. The result is the subtraction
+ * the smaller of the two from the bigger, hence result is always a positive
+ * value.
+ *
+ * Return: an absolute value of the difference between the @a and @b.
+ */
+#define abs_diff(a, b) ({                      \
+       typeof(a) __a = (a);                    \
+       typeof(b) __b = (b);                    \
+       (void)(&__a == &__b);                   \
+       __a > __b ? (__a - __b) : (__b - __a);  \
+})
+
+/**
  * reciprocal_scale - "scale" a value into range [0, ep_ro)
  * @val: value
  * @ep_ro: right open interval endpoint