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Release 4.7 drivers/iio/potentiometer/mcp4531.c

/*
 * Industrial I/O driver for Microchip digital potentiometers
 * Copyright (c) 2015  Axentia Technologies AB
 * Author: Peter Rosin <peda@axentia.se>
 *
 * Datasheet: http://www.microchip.com/downloads/en/DeviceDoc/22096b.pdf
 *
 * DEVID        #Wipers #Positions      Resistor Opts (kOhm)    i2c address
 * mcp4531      1       129             5, 10, 50, 100          010111x
 * mcp4532      1       129             5, 10, 50, 100          01011xx
 * mcp4551      1       257             5, 10, 50, 100          010111x
 * mcp4552      1       257             5, 10, 50, 100          01011xx
 * mcp4631      2       129             5, 10, 50, 100          0101xxx
 * mcp4632      2       129             5, 10, 50, 100          01011xx
 * mcp4651      2       257             5, 10, 50, 100          0101xxx
 * mcp4652      2       257             5, 10, 50, 100          01011xx
 *
 * 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>


struct mcp4531_cfg {
	
int wipers;
	
int max_pos;
	
int kohms;
};


enum mcp4531_type {
	
MCP453x_502,
	
MCP453x_103,
	
MCP453x_503,
	
MCP453x_104,
	
MCP455x_502,
	
MCP455x_103,
	
MCP455x_503,
	
MCP455x_104,
	
MCP463x_502,
	
MCP463x_103,
	
MCP463x_503,
	
MCP463x_104,
	
MCP465x_502,
	
MCP465x_103,
	
MCP465x_503,
	
MCP465x_104,
};


static const struct mcp4531_cfg mcp4531_cfg[] = {
	[MCP453x_502] = { .wipers = 1, .max_pos = 128, .kohms =   5, },
	[MCP453x_103] = { .wipers = 1, .max_pos = 128, .kohms =  10, },
	[MCP453x_503] = { .wipers = 1, .max_pos = 128, .kohms =  50, },
	[MCP453x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, },
	[MCP455x_502] = { .wipers = 1, .max_pos = 256, .kohms =   5, },
	[MCP455x_103] = { .wipers = 1, .max_pos = 256, .kohms =  10, },
	[MCP455x_503] = { .wipers = 1, .max_pos = 256, .kohms =  50, },
	[MCP455x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, },
	[MCP463x_502] = { .wipers = 2, .max_pos = 128, .kohms =   5, },
	[MCP463x_103] = { .wipers = 2, .max_pos = 128, .kohms =  10, },
	[MCP463x_503] = { .wipers = 2, .max_pos = 128, .kohms =  50, },
	[MCP463x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, },
	[MCP465x_502] = { .wipers = 2, .max_pos = 256, .kohms =   5, },
	[MCP465x_103] = { .wipers = 2, .max_pos = 256, .kohms =  10, },
	[MCP465x_503] = { .wipers = 2, .max_pos = 256, .kohms =  50, },
	[MCP465x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, },
};


#define MCP4531_WRITE (0 << 2)

#define MCP4531_INCR  (1 << 2)

#define MCP4531_DECR  (2 << 2)

#define MCP4531_READ  (3 << 2)


#define MCP4531_WIPER_SHIFT (4)


struct mcp4531_data {
	
struct i2c_client *client;
	
const struct mcp4531_cfg *cfg;
};


#define MCP4531_CHANNEL(ch) {                                       \
        .type = IIO_RESISTANCE,                                 \
        .indexed = 1,                                           \
        .output = 1,                                            \
        .channel = (ch),                                        \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
}


static const struct iio_chan_spec mcp4531_channels[] = {
	MCP4531_CHANNEL(0),
	MCP4531_CHANNEL(1),
};


static int mcp4531_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct mcp4531_data *data = iio_priv(indio_dev); int address = chan->channel << MCP4531_WIPER_SHIFT; s32 ret; switch (mask) { case IIO_CHAN_INFO_RAW: ret = i2c_smbus_read_word_swapped(data->client, MCP4531_READ | address); if (ret < 0) return ret; *val = ret; return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: *val = 1000 * data->cfg->kohms; *val2 = data->cfg->max_pos; return IIO_VAL_FRACTIONAL; } return -EINVAL; }

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static int mcp4531_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask) { struct mcp4531_data *data = iio_priv(indio_dev); int address = chan->channel << MCP4531_WIPER_SHIFT; switch (mask) { case IIO_CHAN_INFO_RAW: if (val > data->cfg->max_pos || val < 0) return -EINVAL; break; default: return -EINVAL; } return i2c_smbus_write_byte_data(data->client, MCP4531_WRITE | address | (val >> 8), val & 0xff); }

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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; 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 -EOPNOTSUPP; } indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); if (!indio_dev) return -ENOMEM; data = iio_priv(indio_dev); i2c_set_clientdata(client, indio_dev); data->client = client; data->cfg = &mcp4531_cfg[id->driver_data]; indio_dev->dev.parent = dev; indio_dev->info = &mcp4531_info; indio_dev->channels = mcp4531_channels; indio_dev->num_channels = data->cfg->wipers; indio_dev->name = client->name; return devm_iio_device_register(dev, indio_dev); }

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static const struct i2c_device_id mcp4531_id[] = { { "mcp4531-502", MCP453x_502 }, { "mcp4531-103", MCP453x_103 }, { "mcp4531-503", MCP453x_503 }, { "mcp4531-104", MCP453x_104 }, { "mcp4532-502", MCP453x_502 }, { "mcp4532-103", MCP453x_103 }, { "mcp4532-503", MCP453x_503 }, { "mcp4532-104", MCP453x_104 }, { "mcp4551-502", MCP455x_502 }, { "mcp4551-103", MCP455x_103 }, { "mcp4551-503", MCP455x_503 }, { "mcp4551-104", MCP455x_104 }, { "mcp4552-502", MCP455x_502 }, { "mcp4552-103", MCP455x_103 }, { "mcp4552-503", MCP455x_503 }, { "mcp4552-104", MCP455x_104 }, { "mcp4631-502", MCP463x_502 }, { "mcp4631-103", MCP463x_103 }, { "mcp4631-503", MCP463x_503 }, { "mcp4631-104", MCP463x_104 }, { "mcp4632-502", MCP463x_502 }, { "mcp4632-103", MCP463x_103 }, { "mcp4632-503", MCP463x_503 }, { "mcp4632-104", MCP463x_104 }, { "mcp4651-502", MCP465x_502 }, { "mcp4651-103", MCP465x_103 }, { "mcp4651-503", MCP465x_503 }, { "mcp4651-104", MCP465x_104 }, { "mcp4652-502", MCP465x_502 }, { "mcp4652-103", MCP465x_103 }, { "mcp4652-503", MCP465x_503 }, { "mcp4652-104", MCP465x_104 }, {} }; MODULE_DEVICE_TABLE(i2c, mcp4531_id); static struct i2c_driver mcp4531_driver = { .driver = { .name = "mcp4531", }, .probe = mcp4531_probe, .id_table = mcp4531_id, }; module_i2c_driver(mcp4531_driver); MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); MODULE_DESCRIPTION("MCP4531 digital potentiometer"); MODULE_LICENSE("GPL");

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