]> www.infradead.org Git - users/jedix/linux-maple.git/commit
arm64: dts: ti: k3-am62-verdin: Add Ivy carrier board
authorJoão Paulo Gonçalves <joao.goncalves@toradex.com>
Tue, 24 Sep 2024 12:00:44 +0000 (14:00 +0200)
committerVignesh Raghavendra <vigneshr@ti.com>
Sun, 3 Nov 2024 05:59:57 +0000 (11:29 +0530)
commit881f5e9d808243d27830b3ed294e2e8abda05e62
tree8b31568340af99aeb3a74e02917196d045de097a
parent25c8a5bebd652ad26d99701c9b2e979d7a1c11b4
arm64: dts: ti: k3-am62-verdin: Add Ivy carrier board

Add Toradex Verdin Ivy carrier board support. One notable feature of Ivy
is the analog inputs. These inputs are multiplexed, allowing the same
input to measure either voltage or current. For current measurements,
a GPIO switch enables or disables the shunt resistor. This process is
automatically managed by the Linux kernel using the IIO and MUX
subsystems. Voltage measurement is always enabled, but the voltage
measured by the ADC is scaled by a cascade voltage divider. In the
device tree, the equivalent gain of the voltage divider is used, which
can be calculated as follows:

   ------------
   +          |
     .-.
  R1=30K     | |
     | |
     '-'
      |-------------------
Analog Input (AIN)    |           |
     .-.        .-.
      R2=10K | |         R3=30K | |
     | |        | |
     '-'        '-'
      |           |
      |           |--------
      |         .-.      +
      |    R4=10K | |
      |         | |      ADC Input (Channels 0 and 1)
      |         '-'
   -          |           |       -
   -----------|           |--------
     ===        ===
     GND        GND

Vin  = Analog Input (AIN)
Vout = ADC Input
Rth  = Thevenin Equiv. Resistance
Vth  = Thevenin Equiv. Voltage
RL   = Load Resistor

R1 = 30K, R2 = 10K, R3 = 30K, R4 = 10K
RL = R4 = 10K

Rth  = (R1 // R2) + R3 = 37500 Ohms
Vth  = (Vin * R2) / (R1 + R2) = Vin/4;
Vout = (Vth * RL)/ (Rth + RL) = Vth/4.75 = Vin/19
Gain = Vout/Vin = 1/19

https://www.toradex.com/products/carrier-board/ivy-carrier-board

Signed-off-by: João Paulo Gonçalves <joao.goncalves@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20240924120044.130913-4-francesco@dolcini.it
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
arch/arm64/boot/dts/ti/Makefile
arch/arm64/boot/dts/ti/k3-am62-verdin-ivy.dtsi [new file with mode: 0644]
arch/arm64/boot/dts/ti/k3-am625-verdin-nonwifi-ivy.dts [new file with mode: 0644]
arch/arm64/boot/dts/ti/k3-am625-verdin-wifi-ivy.dts [new file with mode: 0644]