On Wed, 31 Jul 2019 16:07:05 +0200 Martin Kaiser <martin@xxxxxxxxx> wrote: > Add a driver for the Maxim Integrated MAX5432-MAX5435 family of digital > potentiometers. > > These potentiometers are connected via I2C and have 32 wiper > positions. > > Supported functionality > - set the volatile wiper position > - read the potentiometer scale > > Datasheet: > https://datasheets.maximintegrated.com/en/ds/MAX5432-MAX5435.pdf > > Signed-off-by: Martin Kaiser <martin@xxxxxxxxx> Looks good. Applied to the togreg branch of iio.git and pushed out as testing for the autobuilders to play with it. Thanks, Jonathan > --- > changes in v4 > - fix the dt bindings > - replace ic20 with i2c > - document the reg property > - add additionalProperties and required > > changes in v3 > - split dt bindings and driver code into separate patches > - use yaml format for dt bindings > - fix formatting of parameter lists > > changes in v2 > - use MAX5432_ prefix for all defines > - fix indentation > - convert void * to unsigned long, not to u32 > (warning from kbuild test robot) > > drivers/iio/potentiometer/Kconfig | 11 +++ > drivers/iio/potentiometer/Makefile | 1 + > drivers/iio/potentiometer/max5432.c | 135 ++++++++++++++++++++++++++++++++++++ > 3 files changed, 147 insertions(+) > create mode 100644 drivers/iio/potentiometer/max5432.c > > diff --git a/drivers/iio/potentiometer/Kconfig b/drivers/iio/potentiometer/Kconfig > index ebc7c72a5e36..4cac0173db8b 100644 > --- a/drivers/iio/potentiometer/Kconfig > +++ b/drivers/iio/potentiometer/Kconfig > @@ -26,6 +26,17 @@ config DS1803 > To compile this driver as a module, choose M here: the > module will be called ds1803. > > +config MAX5432 > + tristate "Maxim MAX5432-MAX5435 Digital Potentiometer driver" > + depends on I2C > + help > + Say yes here to build support for the Maxim > + MAX5432, MAX5433, MAX5434 and MAX5435 digital > + potentiometer chips. > + > + To compile this driver as a module, choose M here: the > + module will be called max5432. > + > config MAX5481 > tristate "Maxim MAX5481-MAX5484 Digital Potentiometer driver" > depends on SPI > diff --git a/drivers/iio/potentiometer/Makefile b/drivers/iio/potentiometer/Makefile > index 8ff55138cf12..091adf3cdd0b 100644 > --- a/drivers/iio/potentiometer/Makefile > +++ b/drivers/iio/potentiometer/Makefile > @@ -6,6 +6,7 @@ > # When adding new entries keep the list in alphabetical order > obj-$(CONFIG_AD5272) += ad5272.o > obj-$(CONFIG_DS1803) += ds1803.o > +obj-$(CONFIG_MAX5432) += max5432.o > obj-$(CONFIG_MAX5481) += max5481.o > obj-$(CONFIG_MAX5487) += max5487.o > obj-$(CONFIG_MCP4018) += mcp4018.o > diff --git a/drivers/iio/potentiometer/max5432.c b/drivers/iio/potentiometer/max5432.c > new file mode 100644 > index 000000000000..641b1821fdf6 > --- /dev/null > +++ b/drivers/iio/potentiometer/max5432.c > @@ -0,0 +1,135 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * Maxim Integrated MAX5432-MAX5435 digital potentiometer driver > + * Copyright (C) 2019 Martin Kaiser <martin@xxxxxxxxx> > + * > + * Datasheet: > + * https://datasheets.maximintegrated.com/en/ds/MAX5432-MAX5435.pdf > + */ > + > +#include <linux/i2c.h> > +#include <linux/iio/iio.h> > +#include <linux/limits.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/of_device.h> > + > +/* All chip variants have 32 wiper positions. */ > +#define MAX5432_MAX_POS 31 > + > +#define MAX5432_OHM_50K (50 * 1000) > +#define MAX5432_OHM_100K (100 * 1000) > + > +/* Update the volatile (currently active) setting. */ > +#define MAX5432_CMD_VREG 0x11 > + > +struct max5432_data { > + struct i2c_client *client; > + unsigned long ohm; > +}; > + > +static const struct iio_chan_spec max5432_channels[] = { > + { > + .type = IIO_RESISTANCE, > + .indexed = 1, > + .output = 1, > + .channel = 0, > + .address = MAX5432_CMD_VREG, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), > + } > +}; > + > +static int max5432_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + struct max5432_data *data = iio_priv(indio_dev); > + > + if (mask != IIO_CHAN_INFO_SCALE) > + return -EINVAL; > + > + if (unlikely(data->ohm > INT_MAX)) > + return -ERANGE; > + > + *val = data->ohm; > + *val2 = MAX5432_MAX_POS; > + > + return IIO_VAL_FRACTIONAL; > +} > + > +static int max5432_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + struct max5432_data *data = iio_priv(indio_dev); > + u8 data_byte; > + > + if (mask != IIO_CHAN_INFO_RAW) > + return -EINVAL; > + > + if (val < 0 || val > MAX5432_MAX_POS) > + return -EINVAL; > + > + if (val2 != 0) > + return -EINVAL; > + > + /* Wiper position is in bits D7-D3. (D2-D0 are don't care bits.) */ > + data_byte = val << 3; > + return i2c_smbus_write_byte_data(data->client, chan->address, > + data_byte); > +} > + > +static const struct iio_info max5432_info = { > + .read_raw = max5432_read_raw, > + .write_raw = max5432_write_raw, > +}; > + > +static int max5432_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct device *dev = &client->dev; > + struct iio_dev *indio_dev; > + struct max5432_data *data; > + > + indio_dev = devm_iio_device_alloc(dev, sizeof(struct max5432_data)); > + if (!indio_dev) > + return -ENOMEM; > + > + i2c_set_clientdata(client, indio_dev); > + > + data = iio_priv(indio_dev); > + data->client = client; > + data->ohm = (unsigned long)of_device_get_match_data(dev); > + > + indio_dev->dev.parent = dev; > + indio_dev->info = &max5432_info; > + indio_dev->channels = max5432_channels; > + indio_dev->num_channels = ARRAY_SIZE(max5432_channels); > + indio_dev->name = client->name; > + > + return devm_iio_device_register(dev, indio_dev); > +} > + > +static const struct of_device_id max5432_dt_ids[] = { > + { .compatible = "maxim,max5432", .data = (void *)MAX5432_OHM_50K }, > + { .compatible = "maxim,max5433", .data = (void *)MAX5432_OHM_100K }, > + { .compatible = "maxim,max5434", .data = (void *)MAX5432_OHM_50K }, > + { .compatible = "maxim,max5435", .data = (void *)MAX5432_OHM_100K }, > + { /* sentinel */ } > +}; > +MODULE_DEVICE_TABLE(of, max5432_dt_ids); > + > +static struct i2c_driver max5432_driver = { > + .driver = { > + .name = "max5432", > + .of_match_table = of_match_ptr(max5432_dt_ids), > + }, > + .probe = max5432_probe, > +}; > + > +module_i2c_driver(max5432_driver); > + > +MODULE_AUTHOR("Martin Kaiser <martin@xxxxxxxxx>"); > +MODULE_DESCRIPTION("max5432-max5435 digital potentiometers"); > +MODULE_LICENSE("GPL v2");
