diff options
Diffstat (limited to 'drivers/misc/ad525x_dpot.c')
-rw-r--r-- | drivers/misc/ad525x_dpot.c | 666 |
1 files changed, 666 insertions, 0 deletions
diff --git a/drivers/misc/ad525x_dpot.c b/drivers/misc/ad525x_dpot.c new file mode 100644 index 00000000000..30a59f2bacd --- /dev/null +++ b/drivers/misc/ad525x_dpot.c @@ -0,0 +1,666 @@ +/* + * ad525x_dpot: Driver for the Analog Devices AD525x digital potentiometers + * Copyright (c) 2009 Analog Devices, Inc. + * Author: Michael Hennerich <hennerich@blackfin.uclinux.org> + * + * DEVID #Wipers #Positions Resistor Options (kOhm) + * AD5258 1 64 1, 10, 50, 100 + * AD5259 1 256 5, 10, 50, 100 + * AD5251 2 64 1, 10, 50, 100 + * AD5252 2 256 1, 10, 50, 100 + * AD5255 3 512 25, 250 + * AD5253 4 64 1, 10, 50, 100 + * AD5254 4 256 1, 10, 50, 100 + * + * See Documentation/misc-devices/ad525x_dpot.txt for more info. + * + * derived from ad5258.c + * Copyright (c) 2009 Cyber Switching, Inc. + * Author: Chris Verges <chrisv@cyberswitching.com> + * + * derived from ad5252.c + * Copyright (c) 2006 Michael Hennerich <hennerich@blackfin.uclinux.org> + * + * Licensed under the GPL-2 or later. + */ + +#include <linux/module.h> +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/i2c.h> +#include <linux/delay.h> + +#define DRIVER_NAME "ad525x_dpot" +#define DRIVER_VERSION "0.1" + +enum dpot_devid { + AD5258_ID, + AD5259_ID, + AD5251_ID, + AD5252_ID, + AD5253_ID, + AD5254_ID, + AD5255_ID, +}; + +#define AD5258_MAX_POSITION 64 +#define AD5259_MAX_POSITION 256 +#define AD5251_MAX_POSITION 64 +#define AD5252_MAX_POSITION 256 +#define AD5253_MAX_POSITION 64 +#define AD5254_MAX_POSITION 256 +#define AD5255_MAX_POSITION 512 + +#define AD525X_RDAC0 0 +#define AD525X_RDAC1 1 +#define AD525X_RDAC2 2 +#define AD525X_RDAC3 3 + +#define AD525X_REG_TOL 0x18 +#define AD525X_TOL_RDAC0 (AD525X_REG_TOL | AD525X_RDAC0) +#define AD525X_TOL_RDAC1 (AD525X_REG_TOL | AD525X_RDAC1) +#define AD525X_TOL_RDAC2 (AD525X_REG_TOL | AD525X_RDAC2) +#define AD525X_TOL_RDAC3 (AD525X_REG_TOL | AD525X_RDAC3) + +/* RDAC-to-EEPROM Interface Commands */ +#define AD525X_I2C_RDAC (0x00 << 5) +#define AD525X_I2C_EEPROM (0x01 << 5) +#define AD525X_I2C_CMD (0x80) + +#define AD525X_DEC_ALL_6DB (AD525X_I2C_CMD | (0x4 << 3)) +#define AD525X_INC_ALL_6DB (AD525X_I2C_CMD | (0x9 << 3)) +#define AD525X_DEC_ALL (AD525X_I2C_CMD | (0x6 << 3)) +#define AD525X_INC_ALL (AD525X_I2C_CMD | (0xB << 3)) + +static s32 ad525x_read(struct i2c_client *client, u8 reg); +static s32 ad525x_write(struct i2c_client *client, u8 reg, u8 value); + +/* + * Client data (each client gets its own) + */ + +struct dpot_data { + struct mutex update_lock; + unsigned rdac_mask; + unsigned max_pos; + unsigned devid; +}; + +/* sysfs functions */ + +static ssize_t sysfs_show_reg(struct device *dev, + struct device_attribute *attr, char *buf, u32 reg) +{ + struct i2c_client *client = to_i2c_client(dev); + struct dpot_data *data = i2c_get_clientdata(client); + s32 value; + + mutex_lock(&data->update_lock); + value = ad525x_read(client, reg); + mutex_unlock(&data->update_lock); + + if (value < 0) + return -EINVAL; + /* + * Let someone else deal with converting this ... + * the tolerance is a two-byte value where the MSB + * is a sign + integer value, and the LSB is a + * decimal value. See page 18 of the AD5258 + * datasheet (Rev. A) for more details. + */ + + if (reg & AD525X_REG_TOL) + return sprintf(buf, "0x%04x\n", value & 0xFFFF); + else + return sprintf(buf, "%u\n", value & data->rdac_mask); +} + +static ssize_t sysfs_set_reg(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count, u32 reg) +{ + struct i2c_client *client = to_i2c_client(dev); + struct dpot_data *data = i2c_get_clientdata(client); + unsigned long value; + int err; + + err = strict_strtoul(buf, 10, &value); + if (err) + return err; + + if (value > data->rdac_mask) + value = data->rdac_mask; + + mutex_lock(&data->update_lock); + ad525x_write(client, reg, value); + if (reg & AD525X_I2C_EEPROM) + msleep(26); /* Sleep while the EEPROM updates */ + mutex_unlock(&data->update_lock); + + return count; +} + +static ssize_t sysfs_do_cmd(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count, u32 reg) +{ + struct i2c_client *client = to_i2c_client(dev); + struct dpot_data *data = i2c_get_clientdata(client); + + mutex_lock(&data->update_lock); + ad525x_write(client, reg, 0); + mutex_unlock(&data->update_lock); + + return count; +} + +/* ------------------------------------------------------------------------- */ + +static ssize_t show_rdac0(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, AD525X_I2C_RDAC | AD525X_RDAC0); +} + +static ssize_t set_rdac0(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_set_reg(dev, attr, buf, count, + AD525X_I2C_RDAC | AD525X_RDAC0); +} + +static DEVICE_ATTR(rdac0, S_IWUSR | S_IRUGO, show_rdac0, set_rdac0); + +static ssize_t show_eeprom0(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, AD525X_I2C_EEPROM | AD525X_RDAC0); +} + +static ssize_t set_eeprom0(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_set_reg(dev, attr, buf, count, + AD525X_I2C_EEPROM | AD525X_RDAC0); +} + +static DEVICE_ATTR(eeprom0, S_IWUSR | S_IRUGO, show_eeprom0, set_eeprom0); + +static ssize_t show_tolerance0(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, + AD525X_I2C_EEPROM | AD525X_TOL_RDAC0); +} + +static DEVICE_ATTR(tolerance0, S_IRUGO, show_tolerance0, NULL); + +/* ------------------------------------------------------------------------- */ + +static ssize_t show_rdac1(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, AD525X_I2C_RDAC | AD525X_RDAC1); +} + +static ssize_t set_rdac1(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_set_reg(dev, attr, buf, count, + AD525X_I2C_RDAC | AD525X_RDAC1); +} + +static DEVICE_ATTR(rdac1, S_IWUSR | S_IRUGO, show_rdac1, set_rdac1); + +static ssize_t show_eeprom1(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, AD525X_I2C_EEPROM | AD525X_RDAC1); +} + +static ssize_t set_eeprom1(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_set_reg(dev, attr, buf, count, + AD525X_I2C_EEPROM | AD525X_RDAC1); +} + +static DEVICE_ATTR(eeprom1, S_IWUSR | S_IRUGO, show_eeprom1, set_eeprom1); + +static ssize_t show_tolerance1(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, + AD525X_I2C_EEPROM | AD525X_TOL_RDAC1); +} + +static DEVICE_ATTR(tolerance1, S_IRUGO, show_tolerance1, NULL); + +/* ------------------------------------------------------------------------- */ + +static ssize_t show_rdac2(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, AD525X_I2C_RDAC | AD525X_RDAC2); +} + +static ssize_t set_rdac2(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_set_reg(dev, attr, buf, count, + AD525X_I2C_RDAC | AD525X_RDAC2); +} + +static DEVICE_ATTR(rdac2, S_IWUSR | S_IRUGO, show_rdac2, set_rdac2); + +static ssize_t show_eeprom2(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, AD525X_I2C_EEPROM | AD525X_RDAC2); +} + +static ssize_t set_eeprom2(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_set_reg(dev, attr, buf, count, + AD525X_I2C_EEPROM | AD525X_RDAC2); +} + +static DEVICE_ATTR(eeprom2, S_IWUSR | S_IRUGO, show_eeprom2, set_eeprom2); + +static ssize_t show_tolerance2(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, + AD525X_I2C_EEPROM | AD525X_TOL_RDAC2); +} + +static DEVICE_ATTR(tolerance2, S_IRUGO, show_tolerance2, NULL); + +/* ------------------------------------------------------------------------- */ + +static ssize_t show_rdac3(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, AD525X_I2C_RDAC | AD525X_RDAC3); +} + +static ssize_t set_rdac3(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_set_reg(dev, attr, buf, count, + AD525X_I2C_RDAC | AD525X_RDAC3); +} + +static DEVICE_ATTR(rdac3, S_IWUSR | S_IRUGO, show_rdac3, set_rdac3); + +static ssize_t show_eeprom3(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, AD525X_I2C_EEPROM | AD525X_RDAC3); +} + +static ssize_t set_eeprom3(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_set_reg(dev, attr, buf, count, + AD525X_I2C_EEPROM | AD525X_RDAC3); +} + +static DEVICE_ATTR(eeprom3, S_IWUSR | S_IRUGO, show_eeprom3, set_eeprom3); + +static ssize_t show_tolerance3(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_show_reg(dev, attr, buf, + AD525X_I2C_EEPROM | AD525X_TOL_RDAC3); +} + +static DEVICE_ATTR(tolerance3, S_IRUGO, show_tolerance3, NULL); + +static struct attribute *ad525x_attributes_wipers[4][4] = { + { + &dev_attr_rdac0.attr, + &dev_attr_eeprom0.attr, + &dev_attr_tolerance0.attr, + NULL + }, { + &dev_attr_rdac1.attr, + &dev_attr_eeprom1.attr, + &dev_attr_tolerance1.attr, + NULL + }, { + &dev_attr_rdac2.attr, + &dev_attr_eeprom2.attr, + &dev_attr_tolerance2.attr, + NULL + }, { + &dev_attr_rdac3.attr, + &dev_attr_eeprom3.attr, + &dev_attr_tolerance3.attr, + NULL + } +}; + +static const struct attribute_group ad525x_group_wipers[] = { + {.attrs = ad525x_attributes_wipers[AD525X_RDAC0]}, + {.attrs = ad525x_attributes_wipers[AD525X_RDAC1]}, + {.attrs = ad525x_attributes_wipers[AD525X_RDAC2]}, + {.attrs = ad525x_attributes_wipers[AD525X_RDAC3]}, +}; + +/* ------------------------------------------------------------------------- */ + +static ssize_t set_inc_all(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_do_cmd(dev, attr, buf, count, AD525X_INC_ALL); +} + +static DEVICE_ATTR(inc_all, S_IWUSR, NULL, set_inc_all); + +static ssize_t set_dec_all(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_do_cmd(dev, attr, buf, count, AD525X_DEC_ALL); +} + +static DEVICE_ATTR(dec_all, S_IWUSR, NULL, set_dec_all); + +static ssize_t set_inc_all_6db(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_do_cmd(dev, attr, buf, count, AD525X_INC_ALL_6DB); +} + +static DEVICE_ATTR(inc_all_6db, S_IWUSR, NULL, set_inc_all_6db); + +static ssize_t set_dec_all_6db(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return sysfs_do_cmd(dev, attr, buf, count, AD525X_DEC_ALL_6DB); +} + +static DEVICE_ATTR(dec_all_6db, S_IWUSR, NULL, set_dec_all_6db); + +static struct attribute *ad525x_attributes_commands[] = { + &dev_attr_inc_all.attr, + &dev_attr_dec_all.attr, + &dev_attr_inc_all_6db.attr, + &dev_attr_dec_all_6db.attr, + NULL +}; + +static const struct attribute_group ad525x_group_commands = { + .attrs = ad525x_attributes_commands, +}; + +/* ------------------------------------------------------------------------- */ + +/* i2c device functions */ + +/** + * ad525x_read - return the value contained in the specified register + * on the AD5258 device. + * @client: value returned from i2c_new_device() + * @reg: the register to read + * + * If the tolerance register is specified, 2 bytes are returned. + * Otherwise, 1 byte is returned. A negative value indicates an error + * occurred while reading the register. + */ +static s32 ad525x_read(struct i2c_client *client, u8 reg) +{ + struct dpot_data *data = i2c_get_clientdata(client); + + if ((reg & AD525X_REG_TOL) || (data->max_pos > 256)) + return i2c_smbus_read_word_data(client, (reg & 0xF8) | + ((reg & 0x7) << 1)); + else + return i2c_smbus_read_byte_data(client, reg); +} + +/** + * ad525x_write - store the given value in the specified register on + * the AD5258 device. + * @client: value returned from i2c_new_device() + * @reg: the register to write + * @value: the byte to store in the register + * + * For certain instructions that do not require a data byte, "NULL" + * should be specified for the "value" parameter. These instructions + * include NOP, RESTORE_FROM_EEPROM, and STORE_TO_EEPROM. + * + * A negative return value indicates an error occurred while reading + * the register. + */ +static s32 ad525x_write(struct i2c_client *client, u8 reg, u8 value) +{ + struct dpot_data *data = i2c_get_clientdata(client); + + /* Only write the instruction byte for certain commands */ + if (reg & AD525X_I2C_CMD) + return i2c_smbus_write_byte(client, reg); + + if (data->max_pos > 256) + return i2c_smbus_write_word_data(client, (reg & 0xF8) | + ((reg & 0x7) << 1), value); + else + /* All other registers require instruction + data bytes */ + return i2c_smbus_write_byte_data(client, reg, value); +} + +static int ad525x_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct device *dev = &client->dev; + struct dpot_data *data; + int err = 0; + + dev_dbg(dev, "%s\n", __func__); + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) { + dev_err(dev, "missing I2C functionality for this driver\n"); + goto exit; + } + + data = kzalloc(sizeof(struct dpot_data), GFP_KERNEL); + if (!data) { + err = -ENOMEM; + goto exit; + } + + i2c_set_clientdata(client, data); + mutex_init(&data->update_lock); + + switch (id->driver_data) { + case AD5258_ID: + data->max_pos = AD5258_MAX_POSITION; + err = sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC0]); + break; + case AD5259_ID: + data->max_pos = AD5259_MAX_POSITION; + err = sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC0]); + break; + case AD5251_ID: + data->max_pos = AD5251_MAX_POSITION; + err = sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC1]); + err |= sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC3]); + err |= sysfs_create_group(&dev->kobj, &ad525x_group_commands); + break; + case AD5252_ID: + data->max_pos = AD5252_MAX_POSITION; + err = sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC1]); + err |= sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC3]); + err |= sysfs_create_group(&dev->kobj, &ad525x_group_commands); + break; + case AD5253_ID: + data->max_pos = AD5253_MAX_POSITION; + err = sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC0]); + err |= sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC1]); + err |= sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC2]); + err |= sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC3]); + err |= sysfs_create_group(&dev->kobj, &ad525x_group_commands); + break; + case AD5254_ID: + data->max_pos = AD5254_MAX_POSITION; + err = sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC0]); + err |= sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC1]); + err |= sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC2]); + err |= sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC3]); + err |= sysfs_create_group(&dev->kobj, &ad525x_group_commands); + break; + case AD5255_ID: + data->max_pos = AD5255_MAX_POSITION; + err = sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC0]); + err |= sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC1]); + err |= sysfs_create_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC2]); + err |= sysfs_create_group(&dev->kobj, &ad525x_group_commands); + break; + default: + err = -ENODEV; + goto exit_free; + } + + if (err) { + dev_err(dev, "failed to register sysfs hooks\n"); + goto exit_free; + } + + data->devid = id->driver_data; + data->rdac_mask = data->max_pos - 1; + + dev_info(dev, "%s %d-Position Digital Potentiometer registered\n", + id->name, data->max_pos); + + return 0; + +exit_free: + kfree(data); + i2c_set_clientdata(client, NULL); +exit: + dev_err(dev, "failed to create client\n"); + return err; +} + +static int __devexit ad525x_remove(struct i2c_client *client) +{ + struct dpot_data *data = i2c_get_clientdata(client); + struct device *dev = &client->dev; + + switch (data->devid) { + case AD5258_ID: + case AD5259_ID: + sysfs_remove_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC0]); + break; + case AD5251_ID: + case AD5252_ID: + sysfs_remove_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC1]); + sysfs_remove_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC3]); + sysfs_remove_group(&dev->kobj, &ad525x_group_commands); + break; + case AD5253_ID: + case AD5254_ID: + sysfs_remove_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC0]); + sysfs_remove_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC1]); + sysfs_remove_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC2]); + sysfs_remove_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC3]); + sysfs_remove_group(&dev->kobj, &ad525x_group_commands); + break; + case AD5255_ID: + sysfs_remove_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC0]); + sysfs_remove_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC1]); + sysfs_remove_group(&dev->kobj, + &ad525x_group_wipers[AD525X_RDAC2]); + sysfs_remove_group(&dev->kobj, &ad525x_group_commands); + break; + } + + i2c_set_clientdata(client, NULL); + kfree(data); + + return 0; +} + +static const struct i2c_device_id ad525x_idtable[] = { + {"ad5258", AD5258_ID}, + {"ad5259", AD5259_ID}, + {"ad5251", AD5251_ID}, + {"ad5252", AD5252_ID}, + {"ad5253", AD5253_ID}, + {"ad5254", AD5254_ID}, + {"ad5255", AD5255_ID}, + {} +}; + +MODULE_DEVICE_TABLE(i2c, ad525x_idtable); + +static struct i2c_driver ad525x_driver = { + .driver = { + .owner = THIS_MODULE, + .name = DRIVER_NAME, + }, + .id_table = ad525x_idtable, + .probe = ad525x_probe, + .remove = __devexit_p(ad525x_remove), +}; + +static int __init ad525x_init(void) +{ + return i2c_add_driver(&ad525x_driver); +} + +module_init(ad525x_init); + +static void __exit ad525x_exit(void) +{ + i2c_del_driver(&ad525x_driver); +} + +module_exit(ad525x_exit); + +MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>, " + "Michael Hennerich <hennerich@blackfin.uclinux.org>, "); +MODULE_DESCRIPTION("AD5258/9 digital potentiometer driver"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(DRIVER_VERSION); |