iio: max5487: Add support for Maxim digital potentiometers (9a47894f) · Commits · e / devices / android_kernel_teracube_emerald

drivers/iio/potentiometer/Kconfig

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	@@ -15,6 +15,17 @@ config DS1803
	To compile this driver as a module, choose M here: the		To compile this driver as a module, choose M here: the
	module will be called ds1803.		module will be called ds1803.

			config MAX5487
			tristate "Maxim MAX5487/MAX5488/MAX5489 Digital Potentiometer driver"
			depends on SPI
			help
			Say yes here to build support for the Maxim
			MAX5487, MAX5488, MAX5489 digital potentiometer
			chips.

			To compile this driver as a module, choose M here: the
			module will be called max5487.

	config MCP4131		config MCP4131
	tristate "Microchip MCP413X/414X/415X/416X/423X/424X/425X/426X Digital Potentiometer driver"		tristate "Microchip MCP413X/414X/415X/416X/423X/424X/425X/426X Digital Potentiometer driver"
	depends on SPI		depends on SPI

drivers/iio/potentiometer/Makefile

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	@@ -4,6 +4,7 @@

	# When adding new entries keep the list in alphabetical order		# When adding new entries keep the list in alphabetical order
	obj-$(CONFIG_DS1803) += ds1803.o		obj-$(CONFIG_DS1803) += ds1803.o
			obj-$(CONFIG_MAX5487) += max5487.o
	obj-$(CONFIG_MCP4131) += mcp4131.o		obj-$(CONFIG_MCP4131) += mcp4131.o
	obj-$(CONFIG_MCP4531) += mcp4531.o		obj-$(CONFIG_MCP4531) += mcp4531.o
	obj-$(CONFIG_TPL0102) += tpl0102.o		obj-$(CONFIG_TPL0102) += tpl0102.o

drivers/iio/potentiometer/max5487.c

0 → 100644

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			/*
			* max5487.c - Support for MAX5487, MAX5488, MAX5489 digital potentiometers
			*
			* Copyright (C) 2016 Cristina-Gabriela Moraru <cristina.moraru09@gmail.com>
			*
			* This program is free software; you can redistribute it and/or modify
			* it under the terms of the GNU General Public License version 2 as
			* published by the Free Software Foundation.
			*
			*/
			#include <linux/module.h>
			#include <linux/spi/spi.h>
			#include <linux/acpi.h>

			#include <linux/iio/sysfs.h>
			#include <linux/iio/iio.h>

			#define MAX5487_WRITE_WIPER_A (0x01 << 8)
			#define MAX5487_WRITE_WIPER_B (0x02 << 8)

			/* copy both wiper regs to NV regs */
			#define MAX5487_COPY_AB_TO_NV (0x23 << 8)
			/* copy both NV regs to wiper regs */
			#define MAX5487_COPY_NV_TO_AB (0x33 << 8)

			#define MAX5487_MAX_POS 255

			struct max5487_data {
			struct spi_device *spi;
			int kohms;
			};

			#define MAX5487_CHANNEL(ch, addr) { \
			.type = IIO_RESISTANCE, \
			.indexed = 1, \
			.output = 1, \
			.channel = ch, \
			.address = addr, \
			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
			.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
			}

			static const struct iio_chan_spec max5487_channels[] = {
			MAX5487_CHANNEL(0, MAX5487_WRITE_WIPER_A),
			MAX5487_CHANNEL(1, MAX5487_WRITE_WIPER_B),
			};

			static int max5487_write_cmd(struct spi_device *spi, u16 cmd)
			{
			return spi_write(spi, (const void *) &cmd, sizeof(u16));
			}

			static int max5487_read_raw(struct iio_dev *indio_dev,
			struct iio_chan_spec const *chan,
			int val, int val2, long mask)
			{
			struct max5487_data *data = iio_priv(indio_dev);

			if (mask != IIO_CHAN_INFO_SCALE)
			return -EINVAL;

			val = 1000 data->kohms;
			*val2 = MAX5487_MAX_POS;

			return IIO_VAL_FRACTIONAL;
			}

			static int max5487_write_raw(struct iio_dev *indio_dev,
			struct iio_chan_spec const *chan,
			int val, int val2, long mask)
			{
			struct max5487_data *data = iio_priv(indio_dev);

			if (mask != IIO_CHAN_INFO_RAW)
			return -EINVAL;

			if (val < 0 \|\| val > MAX5487_MAX_POS)
			return -EINVAL;

			return max5487_write_cmd(data->spi, chan->address \| val);
			}

			static const struct iio_info max5487_info = {
			.read_raw = max5487_read_raw,
			.write_raw = max5487_write_raw,
			.driver_module = THIS_MODULE,
			};

			static int max5487_spi_probe(struct spi_device *spi)
			{
			struct iio_dev *indio_dev;
			struct max5487_data *data;
			const struct spi_device_id *id = spi_get_device_id(spi);
			int ret;

			indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
			if (!indio_dev)
			return -ENOMEM;

			dev_set_drvdata(&spi->dev, indio_dev);
			data = iio_priv(indio_dev);

			data->spi = spi;
			data->kohms = id->driver_data;

			indio_dev->info = &max5487_info;
			indio_dev->name = id->name;
			indio_dev->dev.parent = &spi->dev;
			indio_dev->modes = INDIO_DIRECT_MODE;
			indio_dev->channels = max5487_channels;
			indio_dev->num_channels = ARRAY_SIZE(max5487_channels);

			/* restore both wiper regs from NV regs */
			ret = max5487_write_cmd(data->spi, MAX5487_COPY_NV_TO_AB);
			if (ret < 0)
			return ret;

			return iio_device_register(indio_dev);
			}

			static int max5487_spi_remove(struct spi_device *spi)
			{
			struct iio_dev *indio_dev = dev_get_drvdata(&spi->dev);

			iio_device_unregister(indio_dev);

			/* save both wiper regs to NV regs */
			return max5487_write_cmd(spi, MAX5487_COPY_AB_TO_NV);
			}

			static const struct spi_device_id max5487_id[] = {
			{ "MAX5487", 10 },
			{ "MAX5488", 50 },
			{ "MAX5489", 100 },
			{ }
			};
			MODULE_DEVICE_TABLE(spi, max5487_id);

			static const struct acpi_device_id max5487_acpi_match[] = {
			{ "MAX5487", 10 },
			{ "MAX5488", 50 },
			{ "MAX5489", 100 },
			{ },
			};
			MODULE_DEVICE_TABLE(acpi, max5487_acpi_match);

			static struct spi_driver max5487_driver = {
			.driver = {
			.name = "max5487",
			.owner = THIS_MODULE,
			.acpi_match_table = ACPI_PTR(max5487_acpi_match),
			},
			.id_table = max5487_id,
			.probe = max5487_spi_probe,
			.remove = max5487_spi_remove
			};
			module_spi_driver(max5487_driver);

			MODULE_AUTHOR("Cristina-Gabriela Moraru <cristina.moraru09@gmail.com>");
			MODULE_DESCRIPTION("max5487 SPI driver");
			MODULE_LICENSE("GPL v2");