iio: max5487: Add support for Maxim digital potentiometers (9a47894f) · Commits · 戴 / test

drivers/iio/potentiometer/Kconfig

+11 −0

Original line number	Diff line number	Diff line
		@@ -15,6 +15,17 @@ config DS1803
		To compile this driver as a module, choose M here: the
		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
		tristate "Microchip MCP413X/414X/415X/416X/423X/424X/425X/426X Digital Potentiometer driver"
		depends on SPI

drivers/iio/potentiometer/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -4,6 +4,7 @@

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

drivers/iio/potentiometer/max5487.c

0 → 100644

+161 −0

Original line number	Diff line number	Diff line
		/*
		* 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");

Admin message