add ad5293 drivers include

1. no-os initilization
2. calibration, wiper r/w ,hard/soft reset and other operation
3. daisy-chain multiple chip support

Signed-off-by: Mize <[email protected]>

doc/sphinx/source/drivers/ad5293.rst

@@ -0,0 +1 @@
+.. include:: ../../../../drivers/potentiometer/ad5293/README.rst

doc/sphinx/source/drivers_doc.rst

@@ -104,3 +104,10 @@ POWER MANAGEMENT
    drivers/lt8722
    drivers/ltp8800
    drivers/max42500
+
+POTENTIOMETER
+================
+.. toctree::
+   :maxdepth: 1
+
+   drivers/ad5293

drivers/potentiometer/ad5293/README.rst

@@ -0,0 +1,260 @@
+====================
+AD5293 no-OS driver
+====================
+
+Supported Devices
+------------------
+
+`ad5293 <https://www.analog.com/en/products/ad5293.html>`_
+
+Overview
+---------
+The AD5293 is a single-channel, 1024-position digital potentiometer with 
+a <1% end-to-end resistor tolerance error. The AD5293 performs the same 
+electronic adjustment function as a mechanical potentiometer with enhanced 
+resolution, solid state reliability, and superior low temperature coefficient 
+performance. This device is capable of operating at high voltages and supporting 
+both dual-supply operation at ±10.5 V to ±15 V and single-supply operation at 21 V to 30 V.
+(in this documentation, the terms digital potentiometer and RDAC are used interchangeably)
+
+The AD5293 contains a serial interface (SYNC, SCLK, DIN, and
+SDO) that is compatible with SPI standards, as well as most DSPs.
+The device allows data to be written to every register via the SPI.
+
+Applications
+------------
+- Mechanical potentiometer replacement
+- Instrumentation: gain and offset adjustment
+- Programmable voltage-to-current conversion
+- Programmable filters, delays, and time constants
+- Programmable power supply
+- Low resolution DAC replacements
+- Sensor calibration
+
+Device Configuration
+--------------------
+
+Multiple Chips Use
+^^^^^^^^^^^^^^^^^^
+Multiple chips could be used in application, daisy chaining topology can 
+minimizes the number of port pins required from the controlling IC. For 
+this driver, if more than 1 chip are used, daisy-chain topology is required. 
+All RESET pins are required to connect together.
+
+Device Operation
+----------------
+
+Write Operation
+^^^^^^^^^^^^^^^
+In order to write to the RDAC calibration mode, you will need to
+call the **ad5293_update_cali** to update calibration on specific 
+chip struct, then call the **ad5293_write_cali** to perform a write performance.
+
+In order to write to the RDAC wiper value, you will need to
+call the **ad5293_update_wiper** to update wiper value on specific 
+chip struct, then call the **ad5293_write_cali** to perform a write performance.
+**RDAC register write protect register** is only unlocked in **ad5293_write_cali**
+to pervent undesired wiper write.
+
+Each write perform will write all chips, for multiple chips application, 
+update all relevant data before perform write.
+
+Read Operation
+^^^^^^^^^^^^^^
+In order to read the RDAC calibration mode, you will need to
+call the **ad5293_read_reg_cali**, calibration mode will be updated 
+to chip struct.
+
+In order to read the RDAC wiper value, you will need to
+call the **ad5293_read_reg_wiper**, wiper value will be updated 
+to chip struct.
+
+Reset
+^^^^^
+In order to read the RDAC chips, you will need to
+call the **ad5293_hard_reset** to implement hardware reset 
+with a low-to-high transition of the hardware RESET pin,
+or call the **ad5293_soft_reset** to implement software reset 
+through SPI interface. After reset, RDAC registers are loaded 
+with midscale, the control registers are restored with default bits.
+
+Minimize The SDO Power Dissipation
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+The SDO pin contains an open-drain N-channel FET that requires a pull-up 
+resistor if this pin is used. This pin could be place in by calling **ad5293_sdo_setfloat** 
+high impedence to minimize power dissipation. ( User should be careful with this operation, 
+SPI comminications integrity may be affected)
+
+Get Data
+^^^^^^^^
+In order to get the RDAC calibration mode or wiper value from chips struct, 
+you will need to call the **ad5293_get_cali** or **ad5293_get_wiper**, which
+returns data of specified chip.
+
+Shutdown
+^^^^^^^^
+RDAC can be placed in a special state in which Terminal A is open-circuited 
+and Wiper W is connected to Terminal B, this is shutdown mode. Contents in 
+RDAC are not changed and all command through SPI are supported in this mode.
+In order to RDAC to shut down mode, call **ad5293_shutdown** and input parameter
+from enmu type **shutdown_t**.
+
+Driver Initialization
+---------------------
+In order to be able to use the device, you will have to provide the support for
+the communication protocol (SPI) as mentioned above.
+
+Device Struct Description
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: C
+
+        struct ad5293_dev {
+        /* SPI */
+        struct no_os_spi_desc	*spi_desc;
+        /* GPIO */
+        struct no_os_gpio_desc	*gpio_reset;
+        /* number of chips */
+        uint16_t chip_num;
+        /* pointer of chip struct  */
+        struct ad5293_chip_info* chip; //point to chip 0
+    };
+
+ad5293_dev
+    overall device information holder, multiple chips are regards as one device
+no_os_spi_desc
+    no-os lib definded spi device instance handler
+no_os_gpio_desc
+    no-os lib definded gpio instance handler for reset pin
+chip_num
+    number of chips 
+ad5293_chip_info
+    pointer to allocated memory for **ad5293_chip_info** structs, total amount 
+    is chip_num*sizeof(ad5293_chip_info), different chip information is accessed 
+    by different pointer offset(array operation) 
+
+Driver Initialization Example
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+An initialization and test example on stm32 could be
+
+.. code-block:: C
+
+    #define RESET_PORT 0     //PORT A
+    #define RESET_PIN  11
+    #define RDAC_CS_PORT 1   //PORT B
+    #define RDAC_CS_PIN  12
+
+    //function
+    uint32_t get_spi2_clock(void);
+
+    //adi device pointer define
+    struct ad5293_dev* pad5293_dev;
+
+    uint32_t get_spi2_clock(void)
+    {
+        return LL_RCC_GetSPIClockFreq(LL_RCC_SPI123_CLKSOURCE);
+    }
+
+    void rdac_init(void)
+    {
+        int32_t ret = 0;
+        struct ad5293_init_param rdac_init;
+
+        //start timer 5 as delay counter
+        delay_init();
+
+        struct no_os_gpio_init_param RESET_init;
+        struct stm32_gpio_init_param RESET_init_stm;
+
+        RESET_init.port = RESET_PORT;
+        RESET_init.number = RESET_PIN;
+        RESET_init.pull = NO_OS_PULL_NONE;
+        RESET_init.platform_ops = & stm32_gpio_ops;
+        RESET_init.extra = (void*) & RESET_init_stm;
+        RESET_init_stm.mode = GPIO_MODE_OUTPUT_PP;
+        RESET_init_stm.speed = GPIO_SPEED_FREQ_HIGH;
+        RESET_init_stm.alternate = 0;
+
+        rdac_init.gpio_reset = & RESET_init;
+        //spi GPIO init struct preparation
+        struct stm32_spi_init_param stm32_spi_init;
+
+        stm32_spi_init.chip_select_port = RDAC_CS_PORT;   //GPIO CS PORT
+        stm32_spi_init.get_input_clock = & get_spi2_clock;
+        stm32_spi_init.alternate = 0;
+        
+        rdac_init.spi_init.extra = (void*) & stm32_spi_init;
+        rdac_init.spi_init.platform_ops = & stm32_spi_ops;
+        
+        rdac_init.spi_init.device_id = 2;    //spi device 1
+        rdac_init.spi_init.max_speed_hz = 200 * 1000;  //3mHz
+        rdac_init.spi_init.chip_select = RDAC_CS_PIN;     //GPIO CS PIN
+        rdac_init.spi_init.mode = NO_OS_SPI_MODE_1;
+        rdac_init.spi_init.bit_order = NO_OS_SPI_BIT_ORDER_MSB_FIRST;
+        
+        rdac_init.spi_init.platform_delays.cs_delay_first = 0;        //delay before transfer
+        rdac_init.spi_init.platform_delays.cs_delay_last = 0;         //delay after transfer
+
+        rdac_init.chip_num = 6;
+
+        ret = ad5293_init( & pad5293_dev, & rdac_init);
+        if(ret)
+            printf("rdac init error. \r\n");
+
+    }
+
+    void rdac_test(void)
+    {
+        int i, cali_val[pad5293_dev->chip_num];
+        int16_t wp_value[pad5293_dev->chip_num];
+
+
+        ad5293_hard_reset(pad5293_dev);
+
+        no_os_mdelay(1);
+
+        for(i = 0;i < pad5293_dev->chip_num;i++)
+        {
+            ad5293_update_cali(pad5293_dev, CALI_NORMAL, i);
+            ad5293_update_wiper(pad5293_dev, 768, i);
+        }
+
+        ad5293_write_cali(pad5293_dev);
+        ad5293_write_wiper(pad5293_dev);
+
+        ad5293_read_reg_cali(pad5293_dev);
+        ad5293_read_reg_wiper(pad5293_dev);
+
+        no_os_mdelay(1);
+
+        for(i = 0;i < pad5293_dev->chip_num;i++)
+        {
+            cali_val[i] = ad5293_get_cali(pad5293_dev, i);
+            wp_value[i] = ad5293_get_wiper(pad5293_dev, i);
+        }
+
+        ad5293_shutdown(pad5293_dev, SHUTDOWN);
+
+        no_os_mdelay(1);
+
+        ad5293_shutdown(pad5293_dev, NORMAL);
+
+        no_os_mdelay(1);
+
+        ad5293_soft_reset(pad5293_dev);
+
+        no_os_mdelay(1);
+
+        for(i = 0;i < pad5293_dev->chip_num;i++)
+        {
+            ad5293_update_cali(pad5293_dev, CALI_NORMAL, i);
+            ad5293_update_wiper(pad5293_dev, 256, i);
+        }
+
+        ad5293_write_cali(pad5293_dev);
+        ad5293_write_wiper(pad5293_dev);
+
+        ad5293_read_reg_cali(pad5293_dev);
+        ad5293_read_reg_wiper(pad5293_dev);
+
+        no_os_mdelay(1);
+    }