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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
| commit | cf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch) | |
| tree | 757a3d280760c654767631cab5ad8af2d86d1848 /Documentation/fb/internals.rst | |
| download | linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.tar.gz linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.zip | |
Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij:
"Core changes:
- Use the non-blocking mux_state_try_select() in the generic MUX pin
control back-end
- Free pin maps on pinctrl_generic_to_map() failure in the core
helpers
New hardware pin control:
- Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC
(this is for the low power audio, LPASS = Low Power Audio SubSystem
portions)
- Upboard support on top of the Intel pin controller
- Apple T6030 and T6031 support (just compatible strings)
- Samsung Exynos 8855 SoC
- Mediatek MT6858 SoC
- Rockchip RK3308B and RV1106 SoCs
- Airoha EN7523 and AN7563 SoCs
Improvements:
- Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable
- Qualcomm improvements on top of the Qualcomm PDC (power domain
controller) irqchip improvements from tglx:s tree
- Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups
- The NPCM8xx driver has been put into shape fixing many pin and
group definitions
- Some non-urgent Tegra 264 pin assignments are fixed up
- Some non-urgent fixups to Airoha AN7581 and AN7583 registers and
pin assignments, missing features etc"
* tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits)
dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema
pinctrl: meson: sync some modify from A4
pinctrl: meson: a4: Add input enable pin configuration
pinctrl: realtek: rtd1625: remove unused group name spdif_sel
pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13
dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema
Revert "Merge branch 'ib-rsk7204' into devel"
pinctrl: rockchip: Add RV1106 pinctrl support
dt-bindings: pinctrl: rockchip: Add RV1106 compatible
pinctrl: rockchip: Decode drive strength in the get function
pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable
pinctrl: airoha: add support of an7563 SoC
dt-bindings: pinctrl: airoha: add support of an7563 pin controller
pinctrl: airoha: try to find chip scu node by phandle first
pinctrl: airoha: add support of en7523 SoC
dt-bindings: pinctrl: airoha: add support of en7523 pin controller
pinctrl: airoha: an7583: add support for olt pinmux
pinctrl: airoha: an7583: add support for pon_alt pinmux
pinctrl: airoha: an7583: add support for npu_uart pinmux
dt-bindings: pinctrl: airoha: an7583: add missed features
...
Diffstat (limited to 'Documentation/fb/internals.rst')
| -rw-r--r-- | Documentation/fb/internals.rst | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/Documentation/fb/internals.rst b/Documentation/fb/internals.rst new file mode 100644 index 000000000..696b50aa7 --- /dev/null +++ b/Documentation/fb/internals.rst @@ -0,0 +1,86 @@ +============================= +Frame Buffer device internals +============================= + +This is a first start for some documentation about frame buffer device +internals. + +Authors: + +- Geert Uytterhoeven <geert@linux-m68k.org>, 21 July 1998 +- James Simmons <jsimmons@user.sf.net>, Nov 26 2002 + +-------------------------------------------------------------------------------- + +Structures used by the frame buffer device API +============================================== + +The following structures play a role in the game of frame buffer devices. They +are defined in <linux/fb.h>. + +1. Outside the kernel (user space) + + - struct fb_fix_screeninfo + + Device independent unchangeable information about a frame buffer device and + a specific video mode. This can be obtained using the FBIOGET_FSCREENINFO + ioctl. + + - struct fb_var_screeninfo + + Device independent changeable information about a frame buffer device and a + specific video mode. This can be obtained using the FBIOGET_VSCREENINFO + ioctl, and updated with the FBIOPUT_VSCREENINFO ioctl. If you want to pan + the screen only, you can use the FBIOPAN_DISPLAY ioctl. + + - struct fb_cmap + + Device independent colormap information. You can get and set the colormap + using the FBIOGETCMAP and FBIOPUTCMAP ioctls. + + +2. Inside the kernel + + - struct fb_info + + Generic information, API and low level information about a specific frame + buffer device instance (slot number, board address, ...). + + - struct `par` + + Device dependent information that uniquely defines the video mode for this + particular piece of hardware. + + +Visuals used by the frame buffer device API +=========================================== + + +Monochrome (FB_VISUAL_MONO01 and FB_VISUAL_MONO10) +-------------------------------------------------- +Each pixel is either black or white. + + +Pseudo color (FB_VISUAL_PSEUDOCOLOR and FB_VISUAL_STATIC_PSEUDOCOLOR) +--------------------------------------------------------------------- +The whole pixel value is fed through a programmable lookup table that has one +color (including red, green, and blue intensities) for each possible pixel +value, and that color is displayed. + + +True color (FB_VISUAL_TRUECOLOR) +-------------------------------- +The pixel value is broken up into red, green, and blue fields. + + +Direct color (FB_VISUAL_DIRECTCOLOR) +------------------------------------ +The pixel value is broken up into red, green, and blue fields, each of which +are looked up in separate red, green, and blue lookup tables. + + +Grayscale displays +------------------ +Grayscale and static grayscale are special variants of pseudo color and static +pseudo color, where the red, green and blue components are always equal to +each other. |
