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litesom:devicetree:lcd [2017/02/14 21:00]
filug [Backlight]
litesom:devicetree:lcd [2021/05/10 13:40] (current)
kateryna.kozakova
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-====== i.MX6UL and LCD display ======+====== liteSOM and LCD display ====== 
 + 
 +<well> 
 +{{:github-mark-32px.png?nolink |}} 
 + 
 +Example available on [[https://github.com/grinn-pub/examples|GitHub]]. 
 +Check [[https://github.com/grinn-pub/examples/blob/master/configs/grinn_liteboard_lcd_res_defconfig|liteboard LCD + touchscreen]]. 
 +</well>
  
 <columns 100% 50% - -> <columns 100% 50% - ->
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   * ''PWM'' - <tooltip title="to control LCD display backlight">Pulse Width Modulation</tooltip>.   * ''PWM'' - <tooltip title="to control LCD display backlight">Pulse Width Modulation</tooltip>.
  
-Below you can see how to configure [[litesom:liteboard]] to support [[emv:lcd]] module.+Below you can see how to configure [[litesom:liteboard]] to support [[devices:lcd]] module.
  
-<alert type="info">Complete example for [[litesom:liteboard]] and [[emv:lcd]] you can find on our [[https://github.com/grinn-pub/examples|GitHub examples repository]].</alert>+<alert type="info">Complete example for [[litesom:liteboard]] and [[devices:lcd]] you can find on our [[https://github.com/grinn-pub/examples|GitHub examples repository]].</alert>
  
 On [[evm:lcd]] we are using [[https://riverdi.com/product/rvt7-0a800480tnwr00/|RVT7.0A800480TNWR00]] TFT display produced by [[https://riverdi.com/|Riverdi]]. Below you can find short details about this device: On [[evm:lcd]] we are using [[https://riverdi.com/product/rvt7-0a800480tnwr00/|RVT7.0A800480TNWR00]] TFT display produced by [[https://riverdi.com/|Riverdi]]. Below you can find short details about this device:
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 } }
 </uml> </uml>
-<newcolumn> 
- 
-On [[litesom:liteboard]] you can find dedicated LCD backlight boot converter (see [[http://www.ti.com/product/TPS61042|TPS61042]]) controlled by [[:litesom]] via ''PWM2 output'' pin. 
  
-{{ :litesom:devicetree:litesom_backlight_driver.png?500 |}} 
- 
-Backlight can be controlled directly via ''PWM driver'' but additional ''PWM backlight driver'' will <tooltip title="from software point of view">simplify</tooltip> backlight configuration. 
-</columns> 
- 
-<columns 100% 45% - -> 
 <code> <code>
 / { / {
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 </code> </code>
 <newcolumn> <newcolumn>
 +
 +On [[litesom:liteboard]] you can find dedicated LCD backlight boot converter (see [[https://www.ti.com/product/TPS61042|TPS61042]]) controlled by [[:litesom]] via ''PWM2 output'' pin.
 +
 +{{ :litesom:devicetree:litesom_backlight_driver.png?500 |}}
 +
 +Backlight can be controlled directly via ''PWM driver'' but additional ''PWM backlight driver'' will <tooltip title="from software point of view">simplify</tooltip> backlight configuration.
 +
 +Node ''backlight'' is documented in [[https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt|pwm-backlight.txt]] file.
 +
 +Backlight configured as presented here will:
 +
 +  * generate PWM with 200Hz frequency (period 5000000 ns),  
 +  * use ''PWM2'' peripheral as backlight controller,
 +  * define eight allowed backlight levels: 0%, 2%, 3%, 6%, 13%, 25%, 50%, 100%,
 +  * use 50% as default backlight level.
 +
 +Node ''pinctrl_pwm2'' is information for ''IOMUX controller'' how to configure ''PWM2'' output. On [[litesom:liteboard]] we are using ''GPIO1__IO09''.
 +
 +{{ :litesom:devicetree:litesom_backlight.png?400 |}}
 +
 +Node ''pwm2'' is configured as documented in [[https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/pwm/pwm.txt|pwm.txt]].
 </columns> </columns>
 +
 +
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  • Last modified: 2017/02/14 21:00
  • by filug