Documentation/devicetree/bindings/leds/leds-aat1290.txt

   1 * Skyworks Solutions, Inc. AAT1290 Current Regulator for Flash LEDs
   2
   3 The device is controlled through two pins: FL_EN and EN_SET. The pins when,
   4 asserted high, enable flash strobe and movie mode (max 1/2 of flash current)
   5 respectively. In order to add a capability of selecting the strobe signal source
   6 (e.g. CPU or camera sensor) there is an additional switch required, independent
   7 of the flash chip. The switch is controlled with pin control.
   8
   9 Required properties:
  10
  11 - compatible : Must be "skyworks,aat1290".
  12 - flen-gpios : Must be device tree identifier of the flash device FL_EN pin.
  13 - enset-gpios : Must be device tree identifier of the flash device EN_SET pin.
  14
  15 Optional properties:
  16 - pinctrl-names : Must contain entries: "default", "host", "isp". Entries
  17                 "default" and "host" must refer to the same pin configuration
  18                 node, which sets the host as a strobe signal provider. Entry
  19                 "isp" must refer to the pin configuration node, which sets the
  20                 ISP as a strobe signal provider.
  21
  22 A discrete LED element connected to the device must be represented by a child
  23 node - see Documentation/devicetree/bindings/leds/common.txt.
  24
  25 Required properties of the LED child node:
  26 - led-max-microamp : see Documentation/devicetree/bindings/leds/common.txt
  27 - flash-max-microamp : see Documentation/devicetree/bindings/leds/common.txt
  28                        Maximum flash LED supply current can be calculated using
  29                        following formula: I = 1A * 162kohm / Rset.
  30 - flash-max-timeout-us : see Documentation/devicetree/bindings/leds/common.txt
  31                          Maximum flash timeout can be calculated using following
  32                          formula: T = 8.82 * 10^9 * Ct.
  33
  34 Optional properties of the LED child node:
  35 - label : see Documentation/devicetree/bindings/leds/common.txt
  36
  37 Example (by Ct = 220nF, Rset = 160kohm and exynos4412-trats2 board with
  38 a switch that allows for routing strobe signal either from the host or from
  39 the camera sensor):
  40
  41 #include "exynos4412.dtsi"
  42
  43 aat1290 {
  44         compatible = "skyworks,aat1290";
  45         flen-gpios = <&gpj1 1 GPIO_ACTIVE_HIGH>;
  46         enset-gpios = <&gpj1 2 GPIO_ACTIVE_HIGH>;
  47
  48         pinctrl-names = "default", "host", "isp";
  49         pinctrl-0 = <&camera_flash_host>;
  50         pinctrl-1 = <&camera_flash_host>;
  51         pinctrl-2 = <&camera_flash_isp>;
  52
  53         camera_flash: flash-led {
  54                 label = "aat1290-flash";
  55                 led-max-microamp = <520833>;
  56                 flash-max-microamp = <1012500>;
  57                 flash-max-timeout-us = <1940000>;
  58         };
  59 };
  60
  61 &pinctrl_0 {
  62         camera_flash_host: camera-flash-host {
  63                 samsung,pins = "gpj1-0";
  64                 samsung,pin-function = <1>;
  65                 samsung,pin-val = <0>;
  66         };
  67
  68         camera_flash_isp: camera-flash-isp {
  69                 samsung,pins = "gpj1-0";
  70                 samsung,pin-function = <1>;
  71                 samsung,pin-val = <1>;
  72         };
  73 };