drivers: magnetometer: admt4000: Add driver documentation for ADMT4000

Adding driver RST documentation for ADMT4000

Author: Lcompo

doc/sphinx/source/drivers/admt4000.rst

@@ -0,0 +1 @@
+.. include:: ../../../../drivers/magnetometer/admt4000/README.rst

doc/sphinx/source/drivers_doc.rst

@@ -122,4 +122,11 @@ POTENTIOMETER
 .. toctree::
    :maxdepth: 1
 
-   drivers/ad5293
+   drivers/ad5293
+
+MAGNETOMETER
+================
+.. toctree::
+   :maxdepth: 1
+
+   drivers/admt4000

drivers/magnetometer/admt4000/README.rst

@@ -0,0 +1,139 @@
+ADP5055 no-OS driver
+====================
+
+Supported Devices
+-----------------
+
+`ADMT4000 <https://www.analog.com/en/products/admt4000.html>`_
+
+Overview
+--------
+
+TThe ADMT4000 is a magnetic turn count sensor capable 
+of recording the number of rotations of a magnetic 
+system even while the device is powered down. 
+On power-up, the device can be interrogated to report the 
+absolute position of the system. The absolute position 
+is reported through a serial-peripheral interface (SPI). 
+The ADMT4000 counts up to 46-turns of an external 
+magnetic field, which increments the absolute position 
+in the clockwise (CW) direction. 
+The device includes three magnetic sensors, a giant 
+magneto resistance (GMR) turn count sensor, which is 
+used to count the number of rotations on the system, a 
+GMR quadrant detecting sensor, and an anisotropic 
+magnetoresistance (AMR) angle sensor. The AMR angle 
+sensor is used in combination with a GMR quadrant 
+detecting sensor to determine the absolute position of 
+the system within 360°. Combining the GMR turn count 
+sensor output with the AMR angle sensor output 
+enables the device to report the position of the system 
+with a high degree of angular accuracy. 
+
+Applications
+------------
+*  Rotation count detection and storage without 
+power 
+* Contactless absolute position measurement 
+* Brushless DC motor control and positioning 
+* Actuator control and positioning 
+
+ADMT4000 Device Configuration
+----------------------------
+
+Driver Initialization
+---------------------
+
+In order to be able to use the device, you will have to provide the support
+for the communication protocol (SPI).
+
+Status Configuration
+--------------------
+
+Register values of the device can be read using **admt4000_read** API. 
+Additionally the register values can be written using **admt4000_write** API.
+
+
+ADMT4000 Driver Initialization Example
+-------------------------------------
+
+.. code-block:: bash
+    struct admt4000_desc *admt4000_desc;
+    const struct no_os_spi_init_param admt_spi_ip = {
+        .device_id = SPI_DEVICE_ID,
+        .max_speed_hz = SPI_BAUDRATE,
+        .chip_select = SPI_CS,
+        .mode = NO_OS_SPI_MODE_0,
+        .bit_order = NO_OS_SPI_BIT_ORDER_MSB_FIRST,
+        .platform_ops = SPI_OPS,
+        .extra = SPI_EXTRA,
+    };
+    struct admt4000_init_param admt4000_ip = {
+        .spi_init = admt_spi_ip,
+        .gpio_coil_rs = gpio_coil_rs_ip,
+        .gpio_gpio0_busy = gpio_gpio0_busy_ip,
+        .gpio_shdn_n = gpio_shdn_n_ip,
+        .dev_vdd = ADMT4000_3P3V,
+    };
+	ret = admt4000_init(&admt4000_desc, admt4000_ip);
+	if (ret)
+		goto exit;
+
+
+
+ADMT4000 no-OS IIO support
+-------------------------
+The ADMT4000 IIO driver comes on top of the ADMT4000 driver and offers support
+for interfacing IIO clients through libiio.
+
+ADMT4000 IIO Device Configuration
+--------------------------------
+Attributes
+-----------
+
+* ``page - sets and reads the page of the register map to be accessed``
+* ``sequencer_mode - to``
+* ``angle_filt - toggles the filter for the angle sensor``
+* ``conversion_mode - toggles and reads the conversion mode``
+* ``h8_ctrl - toggles the H8 control``
+* ``sdp_gpio0_busy - gets the status of the GPIO0 busy pin``
+* ``sdp_coil_rs - sets the coil for GMR reset``
+
+ADMT4000 IIO Driver Initialization Example
+-----------------------------------------
+
+.. code-block:: bash
+    int ret;
+
+    struct admt4000_iio_dev *admt4000_iio_desc;
+
+    struct admt4000_iio_dev_init_param admt4000_iio_ip = {
+        .admt4000_dev_init = &admt_ip,
+    };
+
+    struct iio_app_desc *app;
+    struct iio_app_init_param app_init_param = { 0 };
+
+    ret = admt4000_iio_init(&admt4000_iio_desc, &admt4000_iio_ip);
+    if (ret)
+        goto exit;
+
+    struct iio_app_device iio_devices[] = {
+        {
+            .name = "admt4000",
+            .dev = admt4000_iio_desc,
+            .dev_descriptor = admt4000_iio_desc->iio_dev,
+        },
+    };
+
+    app_init_param.devices = iio_devices;
+    app_init_param.nb_devices = NO_OS_ARRAY_SIZE(iio_devices);
+    app_init_param.uart_init_params = uart_ip;
+
+    ret = iio_app_init(&app, app_init_param);
+    if (ret)
+        goto iio_admt4000_remove;
+
+    ret = iio_app_run(app);
+
+    iio_app_remove(app);