BB-LCD-ADAFRUIT-18-SPI1: add pwm backlight on P9.14 #75
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Add defintion for PWM backlight control on Adafruit 1.8" TFT LCD. Connect lite pin on lcd to P9.14. Turn on backlight on by setting bl_power to 0 (FB_BLANK_UNBLACK): echo 0 > /sys/devices/platform/backlight_pwm/backlight/backlight_pwm/bl_power That value is specified in: https://www.kernel.org/doc/Documentation/ABI/stable/sysfs-class-backlight What: /sys/class/backlight/<backlight>/bl_power Date: April 2005 KernelVersion: 2.6.12 Contact: Richard Purdie <rpurdie@rpsys.net> Description: Control BACKLIGHT power, values are FB_BLANK_* from fb.h - FB_BLANK_UNBLANK (0) : power on. - FB_BLANK_POWERDOWN (4) : power off Thanks to @notro for the suggestion in PR #68 comment: #68 (comment) Signed-off-by: Drew Fustini <drew@pdp7.com>
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@RobertCNelson @dlech please let me know if you notice any issues with this PR to enable PWM backlight for Adafruit 1.8" LCD |
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Add definition for PWM backlight control on Adafruit 1.8" TFT LCD.
Instructions:
bl_powerto0(FB_BLANK_UNBLACK) per comment by @notro in PR Add overlay for Adafruit 1.8" TFT LCD on SPI1 with tinydrm st7735r #68:NOTE:
FB_BLANK_UNBLACKis specified in sysfs-class-backlight