From: Michael Hennerich <[email protected]>
This driver supports the non-volatile digital potentiometers via I2C:
AD5258, AD5259, AD5251, AD5252, AD5253, AD5254, and AD5255
It provides a sysfs interface to each device for reading/writing.
Signed-off-by: Michael Hennerich <[email protected]>
Signed-off-by: Chris Verges <[email protected]>
Signed-off-by: Mike Frysinger <[email protected]>
---
drivers/misc/Kconfig | 11 +
drivers/misc/Makefile | 1 +
drivers/misc/ad525x_dpot.c | 666 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 678 insertions(+), 0 deletions(-)
create mode 100644 drivers/misc/ad525x_dpot.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index df1f86b..32c8978 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -246,6 +246,17 @@ config EP93XX_PWM
To compile this driver as a module, choose M here: the module will
be called ep93xx_pwm.
+config AD525X_DPOT
+ tristate "Analog Devices AD525x Digital Potentiometers"
+ depends on I2C && SYSFS
+ help
+ If you say yes here, you get support for the Analog Devices
+ AD5258, AD5259, AD5251, AD5252, AD5253, AD5254 and AD5255
+ digital potentiometer chips.
+
+ This driver can also be built as a module. If so, the module
+ will be called ad525x_dpot.
+
source "drivers/misc/c2port/Kconfig"
source "drivers/misc/eeprom/Kconfig"
source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index f982d2e..6c67c00 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_SGI_GRU) += sgi-gru/
obj-$(CONFIG_HP_ILO) += hpilo.o
obj-$(CONFIG_ISL29003) += isl29003.o
obj-$(CONFIG_EP93XX_PWM) += ep93xx_pwm.o
+obj-$(CONFIG_AD525X_DPOT) += ad525x_dpot.o
obj-$(CONFIG_C2PORT) += c2port/
obj-y += eeprom/
obj-y += cb710/
diff --git a/drivers/misc/ad525x_dpot.c b/drivers/misc/ad525x_dpot.c
new file mode 100644
index 0000000..e1d82cd
--- /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 <[email protected]>
+ *
+ * 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
+ *
+ * History:
+ *
+ * derived from ad5258.c
+ * Copyright (c) 2009 Cyber Switching, Inc.
+ * Author: Chris Verges <[email protected]>
+ *
+ * derived from ad5252.c
+ * Copyright (c) 2006 Michael Hennerich <[email protected]>
+ *
+ * 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 <[email protected]>, "
+ "Michael Hennerich <[email protected]>, ");
+MODULE_DESCRIPTION("AD5258/9 digital potentiometer driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRIVER_VERSION);
--
1.6.5.rc1
On Thu, 17 Sep 2009 00:22:37 -0400
Mike Frysinger <[email protected]> wrote:
> This driver supports the non-volatile digital potentiometers via I2C:
> AD5258, AD5259, AD5251, AD5252, AD5253, AD5254, and AD5255
>
> It provides a sysfs interface to each device for reading/writing.
This sysfs interface is by far the most important aspect of this
driver. For both its users and for its reviewers.
Yet you tell us nothing about it! Not in code comments, not in the
changelog, not in supporting documentation.
So some poor idiot (ie: me) is left having to scratch his way through
the implementation trying to work out what the propoed userspace
interface is supposed to look like.
Then I come across something this:
+ if (reg & AD525X_REG_TOL)
+ return sprintf(buf, "0x%04x\n", value & 0xFFFF);
+ else
+ return sprintf(buf, "%u\n", value & data->rdac_mask);
which makes me suspect that the proposed userspace interface is quite
poor.
Patch not applied! Not even close.
On Tue, Sep 29, 2009 at 18:39, Andrew Morton wrote:
> On Thu, 17 Sep 2009 00:22:37 -0400 Mike Frysinger wrote:
>> This driver supports the non-volatile digital potentiometers via I2C:
>> AD5258, AD5259, AD5251, AD5252, AD5253, AD5254, and AD5255
>>
>> It provides a sysfs interface to each device for reading/writing.
>
> This sysfs interface is by far the most important aspect of this
> driver. For both its users and for its reviewers.
>
> Yet you tell us nothing about it! Not in code comments, not in the
> changelog, not in supporting documentation.
>
> So some poor idiot (ie: me) is left having to scratch his way through
> the implementation trying to work out what the propoed userspace
> interface is supposed to look like.
i'll have to get a description from some people
> + if (reg & AD525X_REG_TOL)
> + return sprintf(buf, "0x%04x\n", value & 0xFFFF);
> + else
> + return sprintf(buf, "%u\n", value & data->rdac_mask);
>
> which makes me suspect that the proposed userspace interface is quite
> poor.
not really. the proposed interface was discussed with a few different
people (devs and end users) and reviewed for use across multiple parts
rather than just slapping together a raw interface onto it. if you
actually read the datasheet as indicated in the comment you snipped,
you'll see that the value isnt formatted for trivial conversion. if
the math can easily be done in the kernel, then that's one thing, but
it doesnt look like it to me.
this field is a read-only percentage programmed into the part by the
factory. it can be interpreted by:
MSB: 0 = +
Next 7 MSB: 001 1100 = 28
8 LSB: 0000 1111 = 15 * 2^-8 = 0.06
Tolerance = 28.06%
Rounded Tolerance = 28.1% and therefore
RAB_ACTUAL = 12.810 kΩ
seems to me that this requires floating point support
-mike
On Tue, 29 Sep 2009 21:14:37 -0400 Mike Frysinger <[email protected]> wrote:
> > + __ __ __ if (reg & AD525X_REG_TOL)
> > + __ __ __ __ __ __ __ return sprintf(buf, "0x%04x\n", value & 0xFFFF);
> > + __ __ __ else
> > + __ __ __ __ __ __ __ return sprintf(buf, "%u\n", value & data->rdac_mask);
> >
> > which makes me suspect that the proposed userspace interface is quite
> > poor.
>
> not really.
Think so. We have a sysfs file which under some circumstances will
return a decimal number and which under others will return a hex
number. So userspace is supposed to look for the leading 0x to work
out how to interpret that number?
Or something. Whatever. Perhaps it all makes sense when one has seen
the overall description.
On Tue, Sep 29, 2009 at 21:27, Andrew Morton wrote:
> On Tue, 29 Sep 2009 21:14:37 -0400 Mike Frysinger wrote:
>> > + __ __ __ if (reg & AD525X_REG_TOL)
>> > + __ __ __ __ __ __ __ return sprintf(buf, "0x%04x\n", value & 0xFFFF);
>> > + __ __ __ else
>> > + __ __ __ __ __ __ __ return sprintf(buf, "%u\n", value & data->rdac_mask);
>> >
>> > which makes me suspect that the proposed userspace interface is quite
>> > poor.
>>
>> not really.
>
> Think so. We have a sysfs file which under some circumstances will
> return a decimal number and which under others will return a hex
> number. So userspace is supposed to look for the leading 0x to work
> out how to interpret that number?
>
> Or something. Whatever. Perhaps it all makes sense when one has seen
> the overall description.
no, you're looking at one common function which is called by different
sysfs files. no point in copying & pasting the same code over and
over. all of the rdac files display as a hex file while all the
non-rdac files display as a decimal.
-mike
From: Michael Hennerich <[email protected]>
This driver supports the non-volatile digital potentiometers via I2C:
AD5258, AD5259, AD5251, AD5252, AD5253, AD5254, and AD5255
It provides a sysfs interface to each device for reading/writing which
is documented in Documentation/misc-devices/ad525x_dpot.txt.
Signed-off-by: Michael Hennerich <[email protected]>
Signed-off-by: Chris Verges <[email protected]>
Signed-off-by: Mike Frysinger <[email protected]>
---
v2
- add some docs on sysfs interface
- sort kconfig/makefile list
Documentation/misc-devices/ad525x_dpot.txt | 57 +++
drivers/misc/Kconfig | 14 +
drivers/misc/Makefile | 1 +
drivers/misc/ad525x_dpot.c | 666 ++++++++++++++++++++++++++++
4 files changed, 738 insertions(+), 0 deletions(-)
create mode 100644 Documentation/misc-devices/ad525x_dpot.txt
create mode 100644 drivers/misc/ad525x_dpot.c
diff --git a/Documentation/misc-devices/ad525x_dpot.txt b/Documentation/misc-devices/ad525x_dpot.txt
new file mode 100644
index 0000000..0c9413b
--- /dev/null
+++ b/Documentation/misc-devices/ad525x_dpot.txt
@@ -0,0 +1,57 @@
+---------------------------------
+ AD525x Digital Potentiometers
+---------------------------------
+
+The ad525x_dpot driver exports a simple sysfs interface. This allows you to
+work with the immediate resistance settings as well as update the saved startup
+settings. Access to the factory programmed tolerance is also provided, but
+interpretation of this settings is required by the end application according to
+the specific part in use.
+
+---------
+ Files
+---------
+
+Each dpot device will have a set of eeprom, rdac, and tolerance files. How
+many depends on the actual part you have, as will the range of allowed values.
+
+The eeprom files are used to program the startup value of the device.
+
+The rdac files are used to program the immediate value of the device.
+
+The tolerance files are the read-only factory programmed tolerance settings
+and may vary greatly on a part-by-part basis. For exact interpretation of
+this field, please consult the datasheet for your part. This is presented
+as a hex file for easier parsing.
+
+-----------
+ Example
+-----------
+
+Locate the device in your sysfs tree. This is probably easiest by going into
+the common i2c directory and locating the device by the i2c slave address.
+
+ # ls /sys/bus/i2c/devices/
+ 0-0022 0-0027 0-002f
+
+So assuming the device in question is on the first i2c bus and has the slave
+address of 0x2f, we descend (unrelated sysfs entries have been trimmed).
+
+ # ls /sys/bus/i2c/devices/0-002f/
+ eeprom0 rdac0 tolerance0
+
+You can use simple reads/writes to access these files:
+
+ # cd /sys/bus/i2c/devices/0-002f/
+
+ # cat eeprom0
+ 0
+ # echo 10 > eeprom0
+ # cat eeprom0
+ 10
+
+ # cat rdac0
+ 5
+ # echo 3 > rdac0
+ # cat rdac0
+ 3
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index df1f86b..3e039d3 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -13,6 +13,20 @@ menuconfig MISC_DEVICES
if MISC_DEVICES
+config AD525X_DPOT
+ tristate "Analog Devices AD525x Digital Potentiometers"
+ depends on I2C && SYSFS
+ help
+ If you say yes here, you get support for the Analog Devices
+ AD5258, AD5259, AD5251, AD5252, AD5253, AD5254 and AD5255
+ digital potentiometer chips.
+
+ See Documentation/misc-devices/ad525x_dpot.txt for the
+ userspace interface.
+
+ This driver can also be built as a module. If so, the module
+ will be called ad525x_dpot.
+
config ATMEL_PWM
tristate "Atmel AT32/AT91 PWM support"
depends on AVR32 || ARCH_AT91SAM9263 || ARCH_AT91SAM9RL || ARCH_AT91CAP9
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index f982d2e..e0d4189 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -4,6 +4,7 @@
obj-$(CONFIG_IBM_ASM) += ibmasm/
obj-$(CONFIG_HDPU_FEATURES) += hdpuftrs/
+obj-$(CONFIG_AD525X_DPOT) += ad525x_dpot.o
obj-$(CONFIG_ATMEL_PWM) += atmel_pwm.o
obj-$(CONFIG_ATMEL_SSC) += atmel-ssc.o
obj-$(CONFIG_ATMEL_TCLIB) += atmel_tclib.o
diff --git a/drivers/misc/ad525x_dpot.c b/drivers/misc/ad525x_dpot.c
new file mode 100644
index 0000000..30a59f2
--- /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 <[email protected]>
+ *
+ * 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 <[email protected]>
+ *
+ * derived from ad5252.c
+ * Copyright (c) 2006 Michael Hennerich <[email protected]>
+ *
+ * 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 <[email protected]>, "
+ "Michael Hennerich <[email protected]>, ");
+MODULE_DESCRIPTION("AD5258/9 digital potentiometer driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRIVER_VERSION);
--
1.6.5.rc2