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koreader/frontend/device/sysfs_light.lua
NiLuJe 9c8e55b3e5
Kobo: Yet another attempt at working around the hangs on the latest NXP boards (#10771)
* Notification: Drop the fencing from #10083; it never actually helped, and had subtle side-effects we could do without.
* VirtualKeyBoard: Flash on close, otherwise, some of the fast refresh glitches may be burned into the working buffer until a flash. Making sure we flash ourselves prevent it from sticking around on the page ;).
* util: Move `writeToSysfs` to base (i.e., `ffi/util`), as we need it there (and it actually makes more sense there anyway ;p).
* Bump base for https://github.com/koreader/koreader-base/pull/1645, which is where the actual workaround (hopefully) lives.

Re #8414, #9806, #10558
2023-08-01 23:53:10 +02:00

135 lines
4.3 KiB
Lua

-- Generic frontlight SysFS interface.
-- This also supports the natural light, which consists of additional
-- red and green light LEDs.
local dbg = require("dbg")
local ffiUtil = require("ffi/util")
local SysfsLight = {
frontlight_white = nil,
frontlight_red = nil,
frontlight_green = nil,
frontlight_mixer = nil,
frontlight_ioctl = nil,
nl_min = nil,
nl_max = nil,
nl_inverted = nil,
current_brightness = 0,
current_warmth = 0,
white_gain = 25,
red_gain = 24,
green_gain = 24,
white_offset = -25,
red_offset = 0,
green_offset = -65,
exponent = 0.25,
}
function SysfsLight:new(o)
o = o or {}
setmetatable(o, self)
self.__index = self
if o.init then o:init() end
return o
end
function SysfsLight:setBrightness(brightness)
self:setNaturalBrightness(brightness, nil)
end
dbg:guard(SysfsLight, 'setBrightness',
function(self, brightness)
assert(brightness >= 0 and brightness <= 100,
"Wrong brightness value given!")
end)
function SysfsLight:setWarmth(warmth)
self:setNaturalBrightness(nil, warmth)
end
dbg:guard(SysfsLight, 'setWarmth',
function(self, warmth)
assert(warmth >= 0 and warmth <= 100,
"Wrong warmth value given!")
end)
--- @note: warmth is already in the *native* scale!
function SysfsLight:setNaturalBrightness(brightness, warmth)
local set_brightness = true
local set_warmth = true
if not brightness then
set_brightness = false
brightness = self.current_brightness
end
if not warmth then
set_warmth = false
warmth = self.current_warmth
end
-- Newer devices use a mixer instead of writting values per color.
if self.frontlight_mixer then
if set_brightness then
-- Prefer the ioctl, as it's much lower latency.
if self.frontlight_ioctl then
self.frontlight_ioctl:setBrightness(brightness)
else
ffiUtil.writeToSysfs(brightness, self.frontlight_white)
end
end
-- The mixer might be using inverted values... (cold is nl_max, warm is nl_min)
if set_warmth then
if self.nl_inverted then
ffiUtil.writeToSysfs(self.nl_max - warmth, self.frontlight_mixer)
else
ffiUtil.writeToSysfs(warmth, self.frontlight_mixer)
end
end
else
local red = 0
local green = 0
local white = 0
if brightness > 0 then
-- On Nickel, the values for white/red/green are roughly linearly dependent
-- on the 4th root of brightness and warmth.
white = math.min(self.white_gain * (brightness * (100 - warmth))^self.exponent + self.white_offset, 255)
end
if warmth > 0 then
local brightness_warmth_exp = (brightness * warmth)^self.exponent
red = math.min(self.red_gain * brightness_warmth_exp + self.red_offset, 255)
green = math.min(self.green_gain * brightness_warmth_exp + self.green_offset, 255)
end
white = math.max(white, 0)
red = math.max(red, 0)
green = math.max(green, 0)
self:_set_light_value(self.frontlight_white, math.floor(white))
self:_set_light_value(self.frontlight_green, math.floor(green))
self:_set_light_value(self.frontlight_red, math.floor(red))
end
self.current_brightness = brightness
self.current_warmth = warmth
end
dbg:guard(SysfsLight, 'setNaturalBrightness',
function(self, brightness, warmth)
assert(brightness == nil or (brightness >= 0 and brightness <= 100),
"Wrong brightness value given!")
assert(warmth == nil or (warmth >= 0 and warmth <= 100),
"Wrong warmth value given!")
end)
function SysfsLight:_set_light_value(sysfs_directory, value)
if not sysfs_directory then return end
-- bl_power is '31' when the light is turned on, '0' otherwise.
if (value > 0) then
ffiUtil.writeToSysfs(31, sysfs_directory .. "/bl_power")
else
ffiUtil.writeToSysfs(0, sysfs_directory .. "/bl_power")
end
ffiUtil.writeToSysfs(value, sysfs_directory .. "/brightness")
end
return SysfsLight