Add implementation for Maxim MAX5487, MAX5488, MAX5489 digital potentiometers. Datasheet: http://datasheets.maximintegrated.com/en/ds/MAX5487-MAX5489.pdf Signed-off-by: Cristina Moraru <cristina.moraru09@xxxxxxxxx> CC: Daniel Baluta <daniel.baluta@xxxxxxxxx> --- Changes since v1: Fix spacing Eliminate max5487_cfg struct Add kohms as driver data drivers/iio/potentiometer/Kconfig | 11 +++ drivers/iio/potentiometer/Makefile | 1 + drivers/iio/potentiometer/max5487.c | 169 ++++++++++++++++++++++++++++++++++++ 3 files changed, 181 insertions(+) create mode 100644 drivers/iio/potentiometer/max5487.c diff --git a/drivers/iio/potentiometer/Kconfig b/drivers/iio/potentiometer/Kconfig index fd75db7..242c62d 100644 --- a/drivers/iio/potentiometer/Kconfig +++ b/drivers/iio/potentiometer/Kconfig @@ -5,6 +5,17 @@ menu "Digital potentiometers" +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 potentiomenter + chips. + + To compile this driver as a module, choose M here: the + module will be called max5487. + config MCP4531 tristate "Microchip MCP45xx/MCP46xx Digital Potentiometer driver" depends on I2C diff --git a/drivers/iio/potentiometer/Makefile b/drivers/iio/potentiometer/Makefile index 8afe492..bc2dfd8 100644 --- a/drivers/iio/potentiometer/Makefile +++ b/drivers/iio/potentiometer/Makefile @@ -3,4 +3,5 @@ # # When adding new entries keep the list in alphabetical order +obj-$(CONFIG_MAX5487) += max5487.o obj-$(CONFIG_MCP4531) += mcp4531.o diff --git a/drivers/iio/potentiometer/max5487.c b/drivers/iio/potentiometer/max5487.c new file mode 100644 index 0000000..fa455b8 --- /dev/null +++ b/drivers/iio/potentiometer/max5487.c @@ -0,0 +1,169 @@ +/* + * max5487.c - Support for MAX5487, MAX5488, MAX5489 digital potentiometers + * + * Copyright (C) Cristina-Gabriela Moraru <cristina.moraru09@xxxxxxxxx> + * + * 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/regmap.h> + +#include <linux/iio/sysfs.h> +#include <linux/iio/iio.h> + +#define MAX5487_DRV_NAME "max5487" + +#define MAX5487_WRITE_WIPER_A 0x01 +#define MAX5487_WRITE_WIPER_B 0x02 + +/* copy both wiper regs to NV regs */ +#define MAX5487_COPY_AB_TO_NV 0x23 +/* copy both NV regs to wiper regs */ +#define MAX5487_COPY_NV_TO_AB 0x33 + +#define MAX5487_MAX_POS 255 + +struct max5487_data { + struct regmap *regmap; + 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_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); + + switch (mask) { + case IIO_CHAN_INFO_RAW: + if (val < 0 || val > MAX5487_MAX_POS) + return -EINVAL; + return regmap_write(data->regmap, chan->address, val); + default: + return -EINVAL; + } + return -EINVAL; +} + +static const struct iio_info max5487_info = { + .read_raw = &max5487_read_raw, + .write_raw = &max5487_write_raw, + .driver_module = THIS_MODULE, +}; + +static const struct regmap_config max5487_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + + .max_register = MAX5487_COPY_NV_TO_AB, +}; + +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->regmap = devm_regmap_init_spi(spi, &max5487_regmap_config); + if (IS_ERR(data->regmap)) + return PTR_ERR(data->regmap); + + 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 = regmap_write(data->regmap, MAX5487_COPY_NV_TO_AB, 0); + if (ret < 0) + return ret; + + return devm_iio_device_register(&spi->dev, indio_dev); +} + +static int max5487_spi_remove(struct spi_device *spi) +{ + struct iio_dev *indio_dev = dev_get_drvdata(&spi->dev); + struct max5487_data *data = iio_priv(indio_dev); + + /* save both wiper regs to NV regs */ + return regmap_write(data->regmap, MAX5487_COPY_AB_TO_NV, 0); +} + +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_DRV_NAME, + .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@xxxxxxxxx>"); +MODULE_DESCRIPTION("max5487 SPI driver"); +MODULE_LICENSE("GPL v2"); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
