> Add support for Microchip digital potentiometers and rheostats > MCP4531, MCP4532, MCP4551, MCP4552 > MCP4631, MCP4632, MCP4651, MCP4652 > > These are either single (45xx) or dual (46xx) wipers with either > 129 (4x3x) or 257 (4x5x) steps, and configured either as > potentiometers (4xx1) or rheostats (4xx2). > > Datasheet: http://www.microchip.com/downloads/en/DeviceDoc/22096b.pdf
some comments below I find it useful to state the 7-bit i2c slave address somewhere, 0101xxx in this case > Signed-off-by: Peter Rosin <p...@axentia.se> > --- > MAINTAINERS | 6 ++ > drivers/iio/Kconfig | 1 + > drivers/iio/Makefile | 1 + > drivers/iio/potentiometer/Kconfig | 20 ++++ > drivers/iio/potentiometer/Makefile | 6 ++ > drivers/iio/potentiometer/mcp4531.c | 200 > +++++++++++++++++++++++++++++++++++ > 6 files changed, 234 insertions(+) > create mode 100644 drivers/iio/potentiometer/Kconfig > create mode 100644 drivers/iio/potentiometer/Makefile > create mode 100644 drivers/iio/potentiometer/mcp4531.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index b60e2b2369d2..27862156c7a7 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -6600,6 +6600,12 @@ W: http://linuxtv.org > S: Maintained > F: drivers/media/radio/radio-maxiradio* > > +MCP4531 MICROCHIP DIGITAL POTENTIOMETER DRIVER > +M: Peter Rosin <p...@axentia.se> > +L: linux-...@vger.kernel.org > +S: Maintained > +F: drivers/iio/potentiometer/mcp4531.c > + > MEDIA DRIVERS FOR RENESAS - VSP1 > M: Laurent Pinchart <laurent.pinch...@ideasonboard.com> > L: linux-me...@vger.kernel.org > diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig > index 4011effe4c05..7cc87f322655 100644 > --- a/drivers/iio/Kconfig > +++ b/drivers/iio/Kconfig > @@ -73,6 +73,7 @@ source "drivers/iio/orientation/Kconfig" > if IIO_TRIGGER > source "drivers/iio/trigger/Kconfig" > endif #IIO_TRIGGER > +source "drivers/iio/potentiometer/Kconfig" > source "drivers/iio/pressure/Kconfig" > source "drivers/iio/proximity/Kconfig" > source "drivers/iio/temperature/Kconfig" > diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile > index 698afc2d17ce..121c814e366b 100644 > --- a/drivers/iio/Makefile > +++ b/drivers/iio/Makefile > @@ -23,6 +23,7 @@ obj-y += imu/ > obj-y += light/ > obj-y += magnetometer/ > obj-y += orientation/ > +obj-y += potentiometer/ > obj-y += pressure/ > obj-y += proximity/ > obj-y += temperature/ > diff --git a/drivers/iio/potentiometer/Kconfig > b/drivers/iio/potentiometer/Kconfig > new file mode 100644 > index 000000000000..fd75db73e582 > --- /dev/null > +++ b/drivers/iio/potentiometer/Kconfig > @@ -0,0 +1,20 @@ > +# > +# Potentiometer drivers > +# > +# When adding new entries keep the list in alphabetical order > + > +menu "Digital potentiometers" > + > +config MCP4531 > + tristate "Microchip MCP45xx/MCP46xx Digital Potentiometer driver" > + depends on I2C > + help > + Say yes here to build support for the Microchip > + MCP4531, MCP4532, MCP4551, MCP4552, > + MCP4631, MCP4632, MCP4651, MCP4652 > + digital potentiomenter chips. > + > + To compile this driver as a module, choose M here: the > + module will be called mcp4531. > + > +endmenu > diff --git a/drivers/iio/potentiometer/Makefile > b/drivers/iio/potentiometer/Makefile > new file mode 100644 > index 000000000000..8afe49227012 > --- /dev/null > +++ b/drivers/iio/potentiometer/Makefile > @@ -0,0 +1,6 @@ > +# > +# Makefile for industrial I/O potentiometer drivers > +# > + > +# When adding new entries keep the list in alphabetical order > +obj-$(CONFIG_MCP4531) += mcp4531.o > diff --git a/drivers/iio/potentiometer/mcp4531.c > b/drivers/iio/potentiometer/mcp4531.c > new file mode 100644 > index 000000000000..11039b215080 > --- /dev/null > +++ b/drivers/iio/potentiometer/mcp4531.c > @@ -0,0 +1,200 @@ > +/* > + * Industrial I/O driver for Microchip digital potentiometers > + * Copyright (c) 2015 Axentia Technologies AB > + * Author: Peter Rosin <p...@axentia.se> > + * > + * Datasheet: http://www.microchip.com/downloads/en/DeviceDoc/22096b.pdf > + * > + * DEVID #Wipers #Positions Resistor Options (kOhm) > + * mcp4531 1 129 5, 10, 50, 100 > + * mcp4532 1 129 5, 10, 50, 100 > + * mcp4551 1 257 5, 10, 50, 100 > + * mcp4552 1 257 5, 10, 50, 100 > + * mcp4631 2 129 5, 10, 50, 100 > + * mcp4632 2 129 5, 10, 50, 100 > + * mcp4651 2 257 5, 10, 50, 100 > + * mcp4652 2 257 5, 10, 50, 100 > + * > + * 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/i2c.h> > +#include <linux/err.h> > + > +#include <linux/iio/iio.h> > + drop extra newline > + > +#define MCP4531_CONF(wipers, max_pos, uid) \ > + ((((wipers) & 0xf) << 10) | \ > + (((max_pos) & 0xf) << 6) | \ > + ((uid) & 0x3f)) > + > +#define MCP4531_UID(conf) ((conf) & 0x3f) > +#define MCP4531_MAX_POS(conf) (((conf) >> 6) & 0xf) > +#define MCP4531_WIPERS(conf) (((conf) >> 10) & 0xf) > + > +enum mcp4531_devid { > + MCP4531_ID = MCP4531_CONF(1, 7, 0), > + MCP4532_ID = MCP4531_CONF(1, 7, 1), > + MCP4551_ID = MCP4531_CONF(1, 8, 2), > + MCP4552_ID = MCP4531_CONF(1, 8, 3), > + MCP4631_ID = MCP4531_CONF(2, 7, 4), > + MCP4632_ID = MCP4531_CONF(2, 7, 5), > + MCP4651_ID = MCP4531_CONF(2, 8, 6), > + MCP4652_ID = MCP4531_CONF(2, 8, 7), > +}; > + > +struct mcp4531_data { > + struct i2c_client *client; > + unsigned int max_pos; > + unsigned long devid; > +}; > + > +static const struct iio_chan_spec mcp4531_channels[] = { > + { could use a MACRO to deduplicate common channel parameters > + .type = IIO_RESISTANCE, > + .indexed = 1, > + .output = 1, > + .channel = 0, > + .address = 0 << 4, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), > + }, { > + .type = IIO_RESISTANCE, > + .indexed = 1, > + .output = 1, > + .channel = 1, > + .address = 1 << 4, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), > + } > +}; > + > +static int mcp4531_get_value(struct iio_dev *indio_dev, > + int address, int *val) > +{ > + struct mcp4531_data *data = iio_priv(indio_dev); > + s32 value; ret is arguably a more commonly used name > + > + value = i2c_smbus_read_word_data(data->client, address | 0xc); extra space before address what is 0xc? use a #define maybe > + if (value < 0) > + return value; > + *val = ((value >> 8) & 0xff) | ((value & 0xff) << 8); use i2c_smbus_read_word_swapped(), the chip uses MSB first; no need to shuffle bytes for endianness > + return 0; > +} > + > +static int mcp4531_set_value(struct iio_dev *indio_dev, > + int address, int val) > +{ > + struct mcp4531_data *data = iio_priv(indio_dev); > + > + if (val >= data->max_pos || val < 0) > + return -EINVAL; > + > + return i2c_smbus_write_byte_data(data->client, > + address | (val >> 8), > + val & 0xff); > +} > + > +static int mcp4531_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + int err; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + err = mcp4531_get_value(indio_dev, chan->address, val); > + if (err < 0) > + return err; > + return IIO_VAL_INT; > + } > + > + return -EINVAL; > +} > + > +static int mcp4531_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + return mcp4531_set_value(indio_dev, chan->address, val); > + } > + > + return -EINVAL; > +} > + > +static const struct iio_info mcp4531_info = { > + .read_raw = mcp4531_read_raw, > + .write_raw = mcp4531_write_raw, > + .driver_module = THIS_MODULE, > +}; > + > +static int mcp4531_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct device *dev = &client->dev; > + unsigned long devid = id->driver_data; > + struct mcp4531_data *data; > + struct iio_dev *indio_dev; > + > + if (!i2c_check_functionality(client->adapter, > + I2C_FUNC_SMBUS_WORD_DATA)) { > + dev_err(dev, "SMBUS Word Data not supported\n"); > + return -EIO; > + } > + > + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); > + if (!indio_dev) > + return -ENOMEM; > + data = iio_priv(indio_dev); > + i2c_set_clientdata(client, indio_dev); > + data->client = client; > + data->devid = devid; > + > + data->max_pos = (1 << MCP4531_MAX_POS(devid)) + 1; > + > + indio_dev->dev.parent = dev; > + indio_dev->info = &mcp4531_info; > + indio_dev->channels = mcp4531_channels; > + indio_dev->num_channels = MCP4531_WIPERS(devid); > + indio_dev->name = client->name; > + > + return iio_device_register(indio_dev); use devm_ ... > +} > + > +static int mcp4531_remove(struct i2c_client *client) > +{ ... and drop _remove() > + iio_device_unregister(i2c_get_clientdata(client)); > + return 0; > +} > + > +static const struct i2c_device_id mcp4531_id[] = { > + { "mcp4531", MCP4531_ID }, > + { "mcp4532", MCP4532_ID }, > + { "mcp4551", MCP4551_ID }, > + { "mcp4552", MCP4552_ID }, > + { "mcp4631", MCP4631_ID }, > + { "mcp4632", MCP4632_ID }, > + { "mcp4651", MCP4651_ID }, > + { "mcp4652", MCP4652_ID }, > + {} > +}; > +MODULE_DEVICE_TABLE(i2c, mcp4531_id); > + > +static struct i2c_driver mcp4531_driver = { > + .driver = { > + .name = "mcp4531", > + }, > + .probe = mcp4531_probe, > + .remove = mcp4531_remove, > + .id_table = mcp4531_id, > +}; > + > +module_i2c_driver(mcp4531_driver); > + > +MODULE_AUTHOR("Peter Rosin <p...@axentia.se>"); > +MODULE_DESCRIPTION("MCP4531 digital potentiometer"); > +MODULE_LICENSE("GPL"); > -- Peter Meerwald +43-664-2444418 (mobile) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
