ath79: GL-AR750S: Add I2C Support

The GL-AR750S has an internal header for I2C.

Provide DTS definitions for the i2c-gpio driver.

The I2C drivers; kmod-i2c-core, kmod-i2c-gpio
consume ~20 kB of flash and can be loaded as modules,

Default clock measured ~11.2 ms period, ~89 kHz

The board has well-labeled (unpopulated) headers for serial and I2C
along the front edge of the board (the edge with the LEDs). Looking
from the top, rear of the unit (behind Ethernet jacks)

  -------------------------------------------
       5G_LED        2G_LED      PWR_LED

                 O O O O O O O

                 3 S S G T R G
                 V C D N X X N
                 3 L A D     D

Signed-off-by: Jeff Kletsky <git-commits@allycomm.com>

diff --git a/target/linux/ath79/dts/qca9563_glinet_gl-ar750s.dts b/target/linux/ath79/dts/qca9563_glinet_gl-ar750s.dts
index 24198e80436d003adbc6dd698a24ee642474163d..4f65b2d2e2923e630af743110be23e88349518ba 100644 (file)
--- a/target/linux/ath79/dts/qca9563_glinet_gl-ar750s.dts
+++ b/target/linux/ath79/dts/qca9563_glinet_gl-ar750s.dts
@@ -63,6 +63,13 @@
                };
        };
 
+       i2c: i2c {
+               compatible = "i2c-gpio";
+
+               sda-gpios = <&gpio  5 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
+               scl-gpios = <&gpio 21 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
+       };
+
        usb_vbus: regulator-usb-vbus {
                compatible = "regulator-fixed";