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Date: Mon, 7 Feb 2022 09:34:08 +0530
From: Jagath Jog J <jagathjog1996@...il.com>
To: jic23@...nel.org, lars@...afoo.de, andy.shevchenko@...il.com,
sst@...zta.fm, robh+dt@...nel.org
Cc: linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] iio: potentiometer: Add support for Maxim DS3502
The DS3502 is a 7-bit, nonvolatile digital potentiometer featuring
an output voltage range of up to 15.5V.
DS3502 support is implemented into existing ds1803 driver
Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3502.pdf
Signed-off-by: Jagath Jog J <jagathjog1996@...il.com>
---
drivers/iio/potentiometer/Kconfig | 4 +-
drivers/iio/potentiometer/ds1803.c | 150 +++++++++++++++++++++++------
2 files changed, 120 insertions(+), 34 deletions(-)
diff --git a/drivers/iio/potentiometer/Kconfig b/drivers/iio/potentiometer/Kconfig
index 832df8da2bc6..1741af33672c 100644
--- a/drivers/iio/potentiometer/Kconfig
+++ b/drivers/iio/potentiometer/Kconfig
@@ -27,10 +27,10 @@ config AD5272
module will be called ad5272.
config DS1803
- tristate "Maxim Integrated DS1803 Digital Potentiometer driver"
+ tristate "Maxim Integrated DS1803 and similar Digital Potentiometer driver"
depends on I2C
help
- Say yes here to build support for the Maxim Integrated DS1803
+ Say yes here to build support for the Maxim Integrated DS1803 and DS3502
digital potentiometer chip.
To compile this driver as a module, choose M here: the
diff --git a/drivers/iio/potentiometer/ds1803.c b/drivers/iio/potentiometer/ds1803.c
index 20b45407eaac..5e403e3400f7 100644
--- a/drivers/iio/potentiometer/ds1803.c
+++ b/drivers/iio/potentiometer/ds1803.c
@@ -1,12 +1,15 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * Maxim Integrated DS1803 digital potentiometer driver
+ * Maxim Integrated DS1803 and DS3502 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>
@@ -16,47 +19,88 @@
#include <linux/module.h>
#include <linux/mod_devicetable.h>
-#define DS1803_MAX_POS 255
-#define DS1803_WRITE(chan) (0xa8 | ((chan) + 1))
+#define DS1803_WIPER_0 (0xA9)
+#define DS1803_WIPER_1 (0xAA)
+#define DS3502_WR_IVR (0x00)
+#define DS3502_CR (0x02)
+#define DS3502_MODE0 (0x00)
+#define DS3502_MODE1 (0x80)
enum ds1803_type {
DS1803_010,
DS1803_050,
DS1803_100,
+ DS3502,
};
struct ds1803_cfg {
+ int wipers;
+ int avail[3];
int kohms;
};
static const struct ds1803_cfg ds1803_cfg[] = {
- [DS1803_010] = { .kohms = 10, },
- [DS1803_050] = { .kohms = 50, },
- [DS1803_100] = { .kohms = 100, },
+ [DS1803_010] = { .wipers = 2, .avail = { 0, 1, 255 }, .kohms = 10, },
+ [DS1803_050] = { .wipers = 2, .avail = { 0, 1, 255 }, .kohms = 50, },
+ [DS1803_100] = { .wipers = 2, .avail = { 0, 1, 255 }, .kohms = 100, },
+ [DS3502] = { .wipers = 1, .avail = { 0, 1, 127 }, .kohms = 10, },
+};
+
+struct maxim_potentiometer {
+ const struct iio_chan_spec *channels;
+ u8 num_channels;
};
struct ds1803_data {
struct i2c_client *client;
+ enum ds1803_type chip_type;
const struct ds1803_cfg *cfg;
+ const struct maxim_potentiometer *chip;
};
-#define DS1803_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), \
+#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_CHANNEL(1),
+ DS1803_CHANNEL(0, DS1803_WIPER_0),
+ DS1803_CHANNEL(1, DS1803_WIPER_1),
+};
+
+static const struct iio_chan_spec ds3502_channels[] = {
+ {
+ .type = IIO_RESISTANCE,
+ .indexed = 1,
+ .output = 1,
+ .channel = 0,
+ .address = (DS3502_WR_IVR),
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_ENABLE),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_RAW),
+ },
+};
+
+static const struct maxim_potentiometer maxim_potentiometer_chips[] = {
+ [DS1803_100] = {
+ .channels = ds1803_channels,
+ .num_channels = ARRAY_SIZE(ds1803_channels),
+ },
+ [DS3502] = {
+ .channels = ds3502_channels,
+ .num_channels = ARRAY_SIZE(ds3502_channels),
+ },
};
static int ds1803_read_raw(struct iio_dev *indio_dev,
- struct iio_chan_spec const *chan,
- int *val, int *val2, long mask)
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
{
struct ds1803_data *data = iio_priv(indio_dev);
int pot = chan->channel;
@@ -65,17 +109,28 @@ static int ds1803_read_raw(struct iio_dev *indio_dev,
switch (mask) {
case IIO_CHAN_INFO_RAW:
- ret = i2c_master_recv(data->client, result,
- indio_dev->num_channels);
+ switch (data->chip_type) {
+ case DS1803_010:
+ case DS1803_050:
+ case DS1803_100:
+ ret = i2c_master_recv(data->client, result,
+ indio_dev->num_channels);
+ *val = result[pot];
+ break;
+ case DS3502:
+ ret = i2c_smbus_read_byte_data(data->client, chan->address);
+ *val = ret;
+ break;
+ default:
+ return -EINVAL;
+ }
+
if (ret < 0)
return ret;
-
- *val = result[pot];
return IIO_VAL_INT;
-
case IIO_CHAN_INFO_SCALE:
*val = 1000 * data->cfg->kohms;
- *val2 = DS1803_MAX_POS;
+ *val2 = data->cfg->avail[2];
return IIO_VAL_FRACTIONAL;
}
@@ -83,38 +138,64 @@ static int ds1803_read_raw(struct iio_dev *indio_dev,
}
static int ds1803_write_raw(struct iio_dev *indio_dev,
- struct iio_chan_spec const *chan,
- int val, int val2, long mask)
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
{
struct ds1803_data *data = iio_priv(indio_dev);
- int pot = chan->channel;
+ int max_pos = data->cfg->avail[2];
+ u8 addr = chan->address;
if (val2 != 0)
return -EINVAL;
switch (mask) {
case IIO_CHAN_INFO_RAW:
- if (val > DS1803_MAX_POS || val < 0)
+ if (val > max_pos || val < 0)
+ return -EINVAL;
+ break;
+ case IIO_CHAN_INFO_ENABLE:
+ if (val == 1)
+ val = DS3502_MODE1;
+ else if (val != DS3502_MODE0)
return -EINVAL;
+ addr = DS3502_CR;
break;
default:
return -EINVAL;
}
- return i2c_smbus_write_byte_data(data->client, DS1803_WRITE(pot), val);
+ 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,
+ .read_avail = ds1803_read_avail,
.write_raw = ds1803_write_raw,
};
static int ds1803_probe(struct i2c_client *client,
- const struct i2c_device_id *id)
+ const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct ds1803_data *data;
struct iio_dev *indio_dev;
+ enum ds1803_type chip_type = (id->driver_data <= DS1803_100 ? DS1803_100 : DS3502);
+ const struct maxim_potentiometer *chip = &maxim_potentiometer_chips[chip_type];
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
@@ -125,10 +206,12 @@ static int ds1803_probe(struct i2c_client *client,
data = iio_priv(indio_dev);
data->client = client;
data->cfg = &ds1803_cfg[id->driver_data];
+ data->chip = chip;
+ data->chip_type = chip_type;
indio_dev->info = &ds1803_info;
- indio_dev->channels = ds1803_channels;
- indio_dev->num_channels = ARRAY_SIZE(ds1803_channels);
+ indio_dev->channels = chip->channels;
+ indio_dev->num_channels = chip->num_channels;
indio_dev->name = client->name;
return devm_iio_device_register(dev, indio_dev);
@@ -138,6 +221,7 @@ 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);
@@ -146,6 +230,7 @@ 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);
@@ -162,5 +247,6 @@ static struct i2c_driver ds1803_driver = {
module_i2c_driver(ds1803_driver);
MODULE_AUTHOR("Slawomir Stepien <sst@...zta.fm>");
-MODULE_DESCRIPTION("DS1803 digital potentiometer");
+MODULE_AUTHOR("Jagath Jog J <jagathjog1996@...il.com>");
+MODULE_DESCRIPTION("DS1803 and DS3502 digital potentiometer");
MODULE_LICENSE("GPL v2");
--
2.17.1
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