> Add implementation for Maxim MAX5487, MAX5488, MAX5489 > digital potentiometers.
comments below > Datasheet: > http://datasheets.maximintegrated.com/en/ds/MAX5487-MAX5489.pdf > > Signed-off-by: Cristina Moraru <cristina.morar...@gmail.com> > CC: Daniel Baluta <daniel.bal...@intel.com> > --- > Changes since v2: > Change switch statement in max5487_write_raw > to if statement for consistency > Add blank line before return statement > Eliminate regmap support and use spi_write > Use iio_device_register instead of devm_ version > 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 | 162 > ++++++++++++++++++++++++++++++++++++ > 3 files changed, 174 insertions(+) > create mode 100644 drivers/iio/potentiometer/max5487.c > > diff --git a/drivers/iio/potentiometer/Kconfig > b/drivers/iio/potentiometer/Kconfig > index 6acb238..bb77b50 100644 > --- a/drivers/iio/potentiometer/Kconfig > +++ b/drivers/iio/potentiometer/Kconfig > @@ -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 potentiomenter spelling: 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 > diff --git a/drivers/iio/potentiometer/Makefile > b/drivers/iio/potentiometer/Makefile > index 6007faa..8adb58f 100644 > --- a/drivers/iio/potentiometer/Makefile > +++ b/drivers/iio/potentiometer/Makefile > @@ -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 > diff --git a/drivers/iio/potentiometer/max5487.c > b/drivers/iio/potentiometer/max5487.c > new file mode 100644 > index 0000000..d5c9089 > --- /dev/null > +++ b/drivers/iio/potentiometer/max5487.c > @@ -0,0 +1,162 @@ > +/* > + * max5487.c - Support for MAX5487, MAX5488, MAX5489 digital potentiometers > + * > + * Copyright (C) Cristina-Gabriela Moraru <cristina.morar...@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 > +#define MAX5487_REG_SIZE 16 > + > +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, int cmd) > +{ > + return spi_write(spi, (const void *) &cmd, MAX5487_REG_SIZE); _REG_SIZE is 16, sizeof(cmd) is likely 4 or 8?! maybe cmd should be u16? maybe REG_SIZE should indicate bytes, not bits? > +} > + > +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.morar...@gmail.com>"); > +MODULE_DESCRIPTION("max5487 SPI driver"); > +MODULE_LICENSE("GPL v2"); > -- Peter Meerwald-Stadler +43-664-2444418 (mobile)
