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path: root/drivers/iio/potentiometer/ds1803.c
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-rw-r--r--drivers/iio/potentiometer/ds1803.c263
1 files changed, 263 insertions, 0 deletions
diff --git a/drivers/iio/potentiometer/ds1803.c b/drivers/iio/potentiometer/ds1803.c
new file mode 100644
index 000000000..5c212ed7a
--- /dev/null
+++ b/drivers/iio/potentiometer/ds1803.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Maxim Integrated DS1803 and similar digital potentiometer driver
+ * Copyright (c) 2016 Slawomir Stepien
+ * Copyright (c) 2022 Jagath Jog J
+ *
+ * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS1803.pdf
+ * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3502.pdf
+ *
+ * DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address
+ * ds1803 2 256 10, 50, 100 0101xxx
+ * ds3502 1 128 10 01010xx
+ */
+
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+
+#define DS1803_WIPER_0 0xA9
+#define DS1803_WIPER_1 0xAA
+#define DS3502_WR_IVR 0x00
+
+enum ds1803_type {
+ DS1803_010,
+ DS1803_050,
+ DS1803_100,
+ DS3502,
+};
+
+struct ds1803_cfg {
+ int wipers;
+ int avail[3];
+ int kohms;
+ const struct iio_chan_spec *channels;
+ u8 num_channels;
+ int (*read)(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val);
+};
+
+struct ds1803_data {
+ struct i2c_client *client;
+ const struct ds1803_cfg *cfg;
+};
+
+#define DS1803_CHANNEL(ch, addr) { \
+ .type = IIO_RESISTANCE, \
+ .indexed = 1, \
+ .output = 1, \
+ .channel = (ch), \
+ .address = (addr), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_RAW), \
+}
+
+static const struct iio_chan_spec ds1803_channels[] = {
+ DS1803_CHANNEL(0, DS1803_WIPER_0),
+ DS1803_CHANNEL(1, DS1803_WIPER_1),
+};
+
+static const struct iio_chan_spec ds3502_channels[] = {
+ DS1803_CHANNEL(0, DS3502_WR_IVR),
+};
+
+static int ds1803_read(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val)
+{
+ struct ds1803_data *data = iio_priv(indio_dev);
+ int ret;
+ u8 result[ARRAY_SIZE(ds1803_channels)];
+
+ ret = i2c_master_recv(data->client, result, indio_dev->num_channels);
+ if (ret < 0)
+ return ret;
+
+ *val = result[chan->channel];
+ return ret;
+}
+
+static int ds3502_read(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val)
+{
+ struct ds1803_data *data = iio_priv(indio_dev);
+ int ret;
+
+ ret = i2c_smbus_read_byte_data(data->client, chan->address);
+ if (ret < 0)
+ return ret;
+
+ *val = ret;
+ return ret;
+}
+
+static const struct ds1803_cfg ds1803_cfg[] = {
+ [DS1803_010] = {
+ .wipers = 2,
+ .avail = { 0, 1, 255 },
+ .kohms = 10,
+ .channels = ds1803_channels,
+ .num_channels = ARRAY_SIZE(ds1803_channels),
+ .read = ds1803_read,
+ },
+ [DS1803_050] = {
+ .wipers = 2,
+ .avail = { 0, 1, 255 },
+ .kohms = 50,
+ .channels = ds1803_channels,
+ .num_channels = ARRAY_SIZE(ds1803_channels),
+ .read = ds1803_read,
+ },
+ [DS1803_100] = {
+ .wipers = 2,
+ .avail = { 0, 1, 255 },
+ .kohms = 100,
+ .channels = ds1803_channels,
+ .num_channels = ARRAY_SIZE(ds1803_channels),
+ .read = ds1803_read,
+ },
+ [DS3502] = {
+ .wipers = 1,
+ .avail = { 0, 1, 127 },
+ .kohms = 10,
+ .channels = ds3502_channels,
+ .num_channels = ARRAY_SIZE(ds3502_channels),
+ .read = ds3502_read,
+ },
+};
+
+static int ds1803_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct ds1803_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = data->cfg->read(indio_dev, chan, val);
+ if (ret < 0)
+ return ret;
+
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+ *val = 1000 * data->cfg->kohms;
+ *val2 = data->cfg->avail[2]; /* Max wiper position */
+ return IIO_VAL_FRACTIONAL;
+ }
+
+ return -EINVAL;
+}
+
+static int ds1803_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct ds1803_data *data = iio_priv(indio_dev);
+ u8 addr = chan->address;
+ int max_pos = data->cfg->avail[2];
+
+ if (val2 != 0)
+ return -EINVAL;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (val > max_pos || val < 0)
+ return -EINVAL;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return i2c_smbus_write_byte_data(data->client, addr, val);
+}
+
+static int ds1803_read_avail(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ const int **vals, int *type,
+ int *length, long mask)
+{
+ struct ds1803_data *data = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ *vals = data->cfg->avail;
+ *length = ARRAY_SIZE(data->cfg->avail);
+ *type = IIO_VAL_INT;
+ return IIO_AVAIL_RANGE;
+ }
+ return -EINVAL;
+}
+
+static const struct iio_info ds1803_info = {
+ .read_raw = ds1803_read_raw,
+ .write_raw = ds1803_write_raw,
+ .read_avail = ds1803_read_avail,
+};
+
+static int ds1803_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct ds1803_data *data;
+ struct iio_dev *indio_dev;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, indio_dev);
+
+ data = iio_priv(indio_dev);
+ data->client = client;
+ data->cfg = device_get_match_data(dev);
+ if (!data->cfg)
+ data->cfg = &ds1803_cfg[id->driver_data];
+
+ indio_dev->info = &ds1803_info;
+ indio_dev->channels = data->cfg->channels;
+ indio_dev->num_channels = data->cfg->num_channels;
+ indio_dev->name = client->name;
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id ds1803_dt_ids[] = {
+ { .compatible = "maxim,ds1803-010", .data = &ds1803_cfg[DS1803_010] },
+ { .compatible = "maxim,ds1803-050", .data = &ds1803_cfg[DS1803_050] },
+ { .compatible = "maxim,ds1803-100", .data = &ds1803_cfg[DS1803_100] },
+ { .compatible = "maxim,ds3502", .data = &ds1803_cfg[DS3502] },
+ {}
+};
+MODULE_DEVICE_TABLE(of, ds1803_dt_ids);
+
+static const struct i2c_device_id ds1803_id[] = {
+ { "ds1803-010", DS1803_010 },
+ { "ds1803-050", DS1803_050 },
+ { "ds1803-100", DS1803_100 },
+ { "ds3502", DS3502 },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, ds1803_id);
+
+static struct i2c_driver ds1803_driver = {
+ .driver = {
+ .name = "ds1803",
+ .of_match_table = ds1803_dt_ids,
+ },
+ .probe = ds1803_probe,
+ .id_table = ds1803_id,
+};
+
+module_i2c_driver(ds1803_driver);
+
+MODULE_AUTHOR("Slawomir Stepien <sst@poczta.fm>");
+MODULE_AUTHOR("Jagath Jog J <jagathjog1996@gmail.com>");
+MODULE_DESCRIPTION("DS1803 digital potentiometer");
+MODULE_LICENSE("GPL v2");