Document activelow and chip in gpio

See also evcc commit d5a69db795a2 ("GPIO: Add support for active low").

Signed-off-by: Wojciech Porczyk <wojciech.porczyk@connectpoint.pl>

Author: woju

i18n/en/docusaurus-plugin-content-docs/current/devices/plugins.mdx

@@ -378,15 +378,19 @@ It is particularly suitable for Raspberry Pi and similar single-board computers.
 
 **Parameters**:
 
-| Parameter | Type   | Required | Description                              |
-| --------- | ------ | -------- | ---------------------------------------- |
-| function  | string | yes      | Mode: `read` (input) or `write` (output) |
-| pin       | int    | yes      | Pin number (BCM numbering, e.g. GPIO 17) |
+| Parameter | Type   | Required | Description                                                        |
+| --------- | ------ | -------- | ------------------------------------------------------------------ |
+| function  | string | yes      | Mode: `read` (input) or `write` (output)                           |
+| pin       | int    | yes      | Pin number (BCM numbering, e.g. GPIO 17)                           |
+| activelow | bool   | no       | If `true`, pin will be `true` when at 0 V and `false` at VCC. |
+| chip      | string | no       | GPIO device (default: `gpiochip0`)                                 |
 
 **How it works**:
 
-- **Reading** (`function: read`): Reads the state of a GPIO pin as a boolean value (`true` = HIGH, `false` = LOW)
-- **Writing** (`function: write`): Sets a GPIO pin to HIGH (`true`) or LOW (`false`)
+- **Reading** (`function: read`): Reads the state of a GPIO pin as a boolean
+  value (`true` = HIGH, `false` = LOW, and the other way around if `activelow` is set)
+- **Writing** (`function: write`): Sets a GPIO pin to HIGH (`true`) or LOW
+  (`false`), and vice-versa if `activelow`
 
 Pin numbering follows the BCM scheme (Broadcom numbers, not the physical pin position).
 For a Raspberry Pi pinout, see e.g. [pinout.xyz](https://pinout.xyz/).
@@ -408,7 +412,7 @@ pin: 27 # BCM pin number
 ```
 
 :::note
-This plugin only works on Linux systems with access to `/dev/gpiomem`.
+This plugin only works on Linux systems with access to `/dev/gpiochip0`.
 :::
 
 ### Go <Tag label="read" category="read" /> <Tag label="write" category="write" /> {#go}