Add helpers to convert between q4 fixed point and integer/fraction
values. Also add the format/argument macros required to printk q4 fixed
point variables. The q4 notation is based on the short variant described
by
https://en.wikipedia.org/wiki/Q_(number_format)
where only the number of fraction bits in the fixed point value are
defined, while the full size is deducted from the container type, that
is the size of int for these helpers. Using the fxp_ prefix, which makes
moving these helpers outside of drm to a more generic place easier, if
they prove to be useful.
These are needed by later patches dumping the Display Stream Compression
configuration in DRM core and in the i915 driver to replace the
corresponding bpp_x16 helpers defined locally in the driver.
v2: Use the more generic/descriptive fxp_q4 prefix instead of drm_x16.
(Jani)
Cc: Jani Nikula <[email protected]>
Acked-by: Jani Nikula <[email protected]>
Signed-off-by: Imre Deak <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Several DRM core and helper source files include drm_crtc_helper.h
without needing it or only to get its transitive include statements;
leading to unnecessary compile-time dependencies.
Directly include required headers and drop drm_crtc_helper.h where
possible. The header file, drm_fixed.h, includes <linux/kernel.h>
for lower_32_bits().
v2:
* include drm_crtc_helper.h in drm_crtc_helper.c (Sam)
Signed-off-by: Thomas Zimmermann <[email protected]>
Reviewed-by: Sam Ravnborg <[email protected]>
Acked-by: Jani Nikula <[email protected]>
Acked-by: Alex Deucher <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
drm_fixp_from_fraction allows us to create a fixed point directly
from a fraction, rather than creating fixed point values and dividing
later. This avoids overflow of our 64 bit value for large numbers.
drm_fixp2int_ceil allows us to return the ceiling of our fixed point
value.
[airlied: squash Jordan's fix]
32-bit-build-fix: Jordan Lazare <[email protected]>
Signed-off-by: Harry Wentland <[email protected]>
Cc: [email protected]
Reviewed-by: Alex Deucher <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>
Required for certain driver calculations. Code
was written by Christian König and ported to the
drm by me.
v2: fix 64 bit divides
v3: fix 64 bit for real (math64.h)
Signed-off-by: Alex Deucher <[email protected]>
This helper macro retrieves the fractional part of a fixed20_12 20.12
fixed-point number.
Signed-off-by: Robert Morell <[email protected]>
Signed-off-by: Olof Johansson <[email protected]>
Signed-off-by: Thierry Reding <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>
Jani Nikula