Add support for ltc7871

doc/sphinx/source/drivers/ltc7871.rst

@@ -0,0 +1 @@
+.. include:: ../../../../drivers/power/ltc7871/README.rst

doc/sphinx/source/drivers_doc.rst

@@ -102,6 +102,7 @@ POWER MANAGEMENT
    drivers/ltc2992
    drivers/ltc4162l
    drivers/ltc4296
+   drivers/ltc7871
    drivers/ltm4686
    drivers/lt7170
    drivers/lt7182s

doc/sphinx/source/projects/ltc7871.rst

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+.. include:: ../../../../projects/ltc7871/README.rst

doc/sphinx/source/projects_doc.rst

@@ -75,6 +75,7 @@ POWER MANAGEMENT
    projects/dc2703a
    projects/ltc4162l
    projects/ltc4296
+   projects/ltc7871
    projects/ltm4686
    projects/lt7170
    projects/lt7182s

drivers/power/ltc7871/README.rst

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+LTC7871 no-OS driver
+=====================
+
+Supported Devices
+-----------------
+
+`LTC7871 <https://www.analog.com/LTC7871>`_
+
+Overview
+--------
+
+The LTC7871 is a high performance bidirectional buck or boost switching 
+regulator controller that operates in either buck or boost mode on demand. 
+It regulates in buck mode from VHIGH-to-VLOW and boost mode from 
+VLOW-to-VHIGH depending on a control signal, making it ideal for 48V/12V 
+automotive dual battery systems. An accurate current programming loop 
+regulates the maximum current that can be delivered in either direction. 
+The LTC7871 allows both batteries to supply energy to the load simultaneously 
+by driving energy from either battery to the other.
+
+Its proprietary constant frequency current mode architecture enhances the 
+signal-to-noise ratio enabling low noise operation and provides excellent 
+current matching between phases. Additional features include an SPI-compliant 
+serial interface, discontinuous or continuous mode of operation, OV/UV 
+monitors, independent loop compensation for buck and boost operation, 
+accurate inductor current monitoring and overcurrent protection.
+
+The LTC7871 is available in a 64 pin 10mm × 10mm LWE package.
+
+Applications
+------------
+
+LTC7871
+--------
+
+* Automotive 48V/12V Dual Battery Systems
+* Backup Power Systems
+
+LTC7871 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).
+
+The first API to be called is **ltc7871_init**. Make sure that it returns 0,
+which means that the driver was initialized correctly.
+
+Reseting LT8491
+-----------------
+
+All write/read registers can be reset via **ltc7871_reset**. It writes 1 
+to the reset bit of chip_ctrl register which resets all registers.
+
+Monitoring Fault Condition
+-----------------------------
+
+Fault condition can be read and monitored via several registers.
+**ltc7871_get_mfr_fault** provides the unit'faults condition, **ltc7871_get_mfr_oc_fault** 
+provides unit's  overcurrent fault condition. **ltc7871_get_mfr_noc_fault**. 
+gives the unit's negative overcurrent condition.
+
+Monitoring Configuration of controller programmed by pins
+-----------------------------------------------------------
+
+Using **ltc7871_get_mfr_config1_setting** setcur pin, DRVcc and maximum 
+current sense can be monitored. **ltc7871_get_mfr_config1_setting** provide
+the modes of the device. It tells if the module is on burst mode, DCM,
+Hi-Z mode, spread spectrum mode and boost/buck mode operation.
+
+Managing communcation fault
+-----------------------------
+
+LTC7871 communication operates via SPI. Every transaction should 
+contain parity error checking byte to ensure fata inegrity.
+By using **ltc7871_clear_pec_fault** and **ltc7871_clear_pec_fault**,
+managing/ handling fault related to PEC can be handled.
+
+IDAC configuration
+---------------------
+
+There are three DAC registers that determines vlow and vhigh and setcur
+by controlling the current magnitude and direction. 
+
+To control these, this APIs can be used:
+**ltc7871_get_mfr_idac_vlow**/**ltc7871_set_mfr_idac_vlow**
+**ltc7871_get_mfr_idac_vhigh**/**ltc7871_set_mfr_idac_vhigh**
+**ltc7871_get_mfr_idac_setcur**/**ltc7871_set_mfr_idac_setcur**
+
+Writing  on these DAC registers can also be restricted via 
+**ltc7871_is_write_protected**/**ltc7871_set_write_protect**
+
+
+LTC7871 Driver Initialization Example
+--------------------------------------
+
+.. code-block:: bash
+
+	struct ltc7871_device *dev;
+
+	struct no_os_uart_init_param ltc7871_uart_ip = {
+		.device_id = UART_DEVICE_ID,
+		.baud_rate = UART_BAUDRATE,
+		.size = NO_OS_UART_CS_8,
+		.platform_ops = UART_OPS,
+		.parity = NO_OS_UART_PAR_NO,
+		.stop = NO_OS_UART_STOP_1_BIT,
+		.extra = UART_EXTRA,
+	};
+
+	struct no_os_spi_init_param ltc7871_spi_ip = {
+		.device_id = SPI_DEVICE_ID,
+		.extra = SPI_EXTRA,
+		.max_speed_hz = SPI_BAUDRATE,
+		.platform_ops = SPI_OPS,
+		.chip_select = SPI_CS,
+		.bit_order = NO_OS_SPI_BIT_ORDER_MSB_FIRST,
+		.mode = NO_OS_SPI_MODE_0
+	};
+
+	struct no_os_gpio_init_param ltc7871_pwmen_ip = {
+		.port = GPIO_PWMEN_PORT_NUM,
+		.pull = NO_OS_PULL_NONE,
+		.number = GPIO_PWMEN_PIN_NUM,
+		.platform_ops = GPIO_OPS,
+		.extra = GPIO_EXTRA
+	};
+
+	struct ltc7871_init_param ltc7871_ip = {
+		.spi = &ltc7871_spi_ip,
+		.gpio_pwmen = &ltc7871_pwmen_ip,
+	};
+
+	ret = ltc7871_init(&ltc7871_dev, &ltc7871_ip);
+	if (ret)
+		goto error;
+
+LTC7871 no-OS IIO support
+--------------------------
+
+The LT8491 IIO driver comes on top of the LTC7871 driver and offers support
+for interfacing IIO clients through libiio.
+
+LTC7871 IIO Device Configuration
+---------------------------------
+
+Channel Attributes
+------------------
+
+Debug Attributes
+----------------
+
+The device has a total of 29 debug attributes:
+
+* ``vhigh_ov - The OVLOW pin is higher than 1.2V threshold.``
+* ``vhigh_uv - The OVHIGH pin is higher than 1.2V threshold``
+* ``drvcc_uv - The DRVCC pin is undervoltage``
+* ``v5_uv - The V5 pin is undervoltage``
+* ``vref_bad - The internal reference self-check fails``
+* ``over_temp - An over temperature fault has occurred``
+* ``OC_FAULT_[1-6] - Channel x overcurrent fault has occurred``
+* ``NOC_FAULT_[1-6] - Channel x negative overcurrent fault has occurred``
+* ``ss_done - The soft-start is finished.``
+* ``max_current - The maximum current programmed by the ILIM pin is reached.``
+* ``pgood - The regulated VLOW/VHIGH is within ±10% regulation windows``
+* ``sercur_warning - The SETCUR pin is programmed to be above 1.25V``
+* ``drvcc_set - DRVCC value``
+* ``ilim_set - maximum current sense threshold``
+* ``burst - The controller is in burst mode operation.``
+* ``dcm - The controller is in DCM.``
+* ``hiz - The controller is in Hi-Z mode.``
+* ``sprd - The controller is in spread spectrum mode.``
+* ``buck_boost - buc/boost mode operation``
+
+Global Attributes
+---------------------
+The device has a total of 8 debug attributes:
+
+* ``reset - reset al W/R registers.``
+* ``pec_fault - pec fault bit indicating communication error.``
+* ``write_protect - protects IDAC registers from write.``
+* ``idac_vlow - current DAC values for Vlow.``
+* ``idac_vhigh - current DAC values for Vhigh.``
+* ``idac_setcur - current DAC values for Vsetcur.``
+* ``freq_spread_range - frequency spread range.``
+* ``mod_freq - Modulation signal frequency.``
+
+LTC7871 IIO Driver Initialization Example
+------------------------------------------
+
+.. code-block:: bash
+
+	int ret;
+
+	struct ltc7871_iio_dev *ltc7871_iio_dev;
+	struct ltc7871_iio_dev_init_param ltc7871_iio_ip = {	
+		.ltc7871_init_param = &ltc7871_ip,
+	};
+
+	struct iio_app_desc *app;
+	struct iio_app_init_param app_init_param = { 0 };
+
+	ret = ltc7871_iio_init(&ltc7871_iio_dev, &ltc7871_iio_ip);
+	if (ret)
+		goto exit;
+
+	struct iio_app_device iio_devices[] = {
+		{
+			.name = "ltc7871",
+			.dev = ltc7871_iio_dev,
+			.dev_descriptor = ltc7871_iio_dev->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 = ltc7871_uart_ip;
+
+	ret = iio_app_init(&app, app_init_param);
+	if (ret)
+		goto remove_iio_ltc7871;
+
+	ret = iio_app_run(app);