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Subject[PATCH] iio: dac: ds4422/ds4424 dac driver
Date
From: "Ismail H. Kose" <ihkose@gmail.com>

This patch provides an iio device driver for DS4422/DS4424 chips that support
two/four channel 7-bit Sink/Source Current DAC.

The driver supports device tree and platform files for the configurations.

Datasheet publicly available at:
https://datasheets.maximintegrated.com/en/ds/DS4422-DS4424.pdf

Signed-off-by: Ismail Kose <Ismail.Kose@maximintegrated.com>
---
drivers/iio/dac/Kconfig | 9 +
drivers/iio/dac/Makefile | 1 +
drivers/iio/dac/ds4424.c | 476 +++++++++++++++++++++++++++++++++++++++++
include/linux/iio/dac/ds4424.h | 24 +++
4 files changed, 510 insertions(+)
create mode 100644 drivers/iio/dac/ds4424.c
create mode 100644 include/linux/iio/dac/ds4424.h

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index 25bed2d7d2b9..db6ceba1c76f 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -310,4 +310,13 @@ config VF610_DAC
This driver can also be built as a module. If so, the module will
be called vf610_dac.

+config DS4424
+ tristate "Maxim Integrated DS4422/DS4424 DAC driver"
+ depends on I2C
+ help
+ If you say yes here you get support for Maxim chips DS4422, DS4424.
+
+ This driver can also be built as a module. If so, the module
+ will be called ds4424.
+
endmenu
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index 603587cc2f07..f29f929a0587 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -33,3 +33,4 @@ obj-$(CONFIG_MCP4922) += mcp4922.o
obj-$(CONFIG_STM32_DAC_CORE) += stm32-dac-core.o
obj-$(CONFIG_STM32_DAC) += stm32-dac.o
obj-$(CONFIG_VF610_DAC) += vf610_dac.o
+obj-$(CONFIG_DS4424) += ds4424.o
diff --git a/drivers/iio/dac/ds4424.c b/drivers/iio/dac/ds4424.c
new file mode 100644
index 000000000000..8765bf20ab62
--- /dev/null
+++ b/drivers/iio/dac/ds4424.c
@@ -0,0 +1,476 @@
+/*
+ * Maxim Integrated
+ * 7-bit, Multi-Channel Sink/Source Current DAC Driver
+ * Copyright (C) 2017 Maxim Integrated
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/regulator/consumer.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/driver.h>
+#include <linux/iio/machine.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/dac/ds4424.h>
+
+#define DS4424_DAC_ADDR(chan) ((chan) + 0xf8)
+#define DS4424_SOURCE_I 1
+#define DS4424_SINK_I 0
+
+#define DS4424_CHANNEL(chan) { \
+ .type = IIO_CURRENT, \
+ .indexed = 1, \
+ .output = 1, \
+ .channel = chan, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET), \
+ .address = DS4424_DAC_ADDR(chan), \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = 8, \
+ .storagebits = 8, \
+ }, \
+}
+
+union ds4424_raw_data {
+ struct {
+ u8 dx:7;
+ u8 source_bit:1; /* 1 is source, 0 is sink */
+ };
+ u8 bits;
+};
+
+enum ds4424_device_ids {
+ ID_DS4422,
+ ID_DS4424,
+};
+
+struct ds4424_data {
+ struct i2c_client *client;
+ struct mutex lock;
+ uint16_t raw[DS4424_MAX_DAC_CHANNELS];
+ __maybe_unused uint16_t save[DS4424_MAX_DAC_CHANNELS];
+ uint32_t rfs_res[DS4424_MAX_DAC_CHANNELS];
+ struct regulator *vcc_reg;
+};
+
+static struct iio_map ds4424_iio_maps[] = {
+ { .consumer_dev_name = "ds4424_dac-consumer-dev_name-1",
+ .consumer_channel = "ds4424_dac1",
+ .adc_channel_label = "OUT1"
+ },
+ {
+ .consumer_dev_name = "ds4424_dac-consumer-dev_name-2",
+ .consumer_channel = "ds4424_dac2",
+ .adc_channel_label = "OUT2"
+ },
+ {
+ .consumer_dev_name = "ds4424_dac-consumer-dev_name-3",
+ .consumer_channel = "ds4424_dac3",
+ .adc_channel_label = "OUT3"
+ },
+ {
+ .consumer_dev_name = "ds4424_dac-consumer-dev_name-4",
+ .consumer_channel = "ds4424_dac4",
+ .adc_channel_label = "OUT4"
+ },
+ { },
+};
+
+
+static const struct ds4424_pdata ds4424_pdata = {
+ .rfs_res = {400, 800, 1000, 1600},
+ .dac_iio_map = ds4424_iio_maps,
+};
+
+static const struct iio_chan_spec ds4424_channels[] = {
+ DS4424_CHANNEL(0),
+ DS4424_CHANNEL(1),
+ DS4424_CHANNEL(2),
+ DS4424_CHANNEL(3),
+};
+
+static int ds4424_get_value(struct iio_dev *indio_dev,
+ int *val, int channel)
+{
+ struct ds4424_data *data = iio_priv(indio_dev);
+ int ret;
+
+ mutex_lock(&data->lock);
+ ret = i2c_smbus_write_byte_data(data->client,
+ DS4424_DAC_ADDR(channel), 1);
+ if (ret < 0)
+ goto fail;
+
+ ret = i2c_smbus_read_byte_data(data->client, 1);
+ if (ret < 0)
+ goto fail;
+
+ *val = ret;
+ mutex_unlock(&data->lock);
+ return 0;
+
+fail:
+ mutex_unlock(&data->lock);
+ return ret;
+}
+
+/*
+ * DS4424 DAC control register 8 bits
+ * [7] 0: to sink; 1: to source
+ * [6:0] steps to sink/source
+ * bit[7] looks like a sign bit, but the value of the register is
+ * not a complemental code considering the bit[6:0] is a absolute
+ * distance from the zero point.
+ */
+
+/*
+ * val is positive if sourcing
+ * val is negative if sinking
+ * val can be -127 to 127
+ */
+static int ds4424_set_value(struct iio_dev *indio_dev,
+ int val, struct iio_chan_spec const *chan)
+{
+ struct ds4424_data *data = iio_priv(indio_dev);
+ int ret;
+
+ if (val < 0 || val > U8_MAX)
+ return -EINVAL;
+
+ mutex_lock(&data->lock);
+ ret = i2c_smbus_write_byte_data(data->client,
+ DS4424_DAC_ADDR(chan->channel), val);
+ if (ret < 0) {
+ mutex_unlock(&data->lock);
+ return ret;
+ }
+
+ data->raw[chan->channel] = val;
+ mutex_unlock(&data->lock);
+
+ return 0;
+}
+
+static int ds4424_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ union ds4424_raw_data raw;
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = ds4424_get_value(indio_dev, val, chan->channel);
+ if (ret < 0) {
+ pr_err("%s : ds4424_get_value returned %d\n",
+ __func__, ret);
+ return ret;
+ }
+ raw.bits = *val;
+ *val = raw.dx;
+ if (raw.source_bit == DS4424_SINK_I)
+ *val = -*val;
+ return IIO_VAL_INT;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int ds4424_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ union ds4424_raw_data raw;
+
+ if (val2 != 0)
+ return -EINVAL;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+
+ if (val > S8_MAX || val < S8_MIN)
+ return -EINVAL;
+
+ if (val > 0) {
+ raw.source_bit = DS4424_SOURCE_I;
+ raw.dx = val;
+ } else {
+ raw.source_bit = DS4424_SINK_I;
+ raw.dx = -val;
+ }
+
+ return ds4424_set_value(indio_dev, raw.bits, chan);
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int ds4424_verify_chip(struct iio_dev *indio_dev)
+{
+ int ret = 0, val;
+
+ ret = ds4424_get_value(indio_dev, &val, DS4424_DAC_ADDR(0));
+ if (ret < 0)
+ dev_err(&indio_dev->dev,
+ "ds4424 i2c read failed. ret: %d\n", ret);
+
+ return ret;
+}
+
+static int __maybe_unused ds4424_suspend(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct ds4424_data *data = iio_priv(indio_dev);
+ int ret = 0;
+ u32 i;
+
+ for (i = 0; i < indio_dev->num_channels; i++) {
+ data->save[i] = data->raw[i];
+ ret = ds4424_set_value(indio_dev, 0,
+ &indio_dev->channels[i]);
+ if (ret < 0)
+ return ret;
+ }
+ return ret;
+}
+
+static int __maybe_unused ds4424_resume(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct ds4424_data *data = iio_priv(indio_dev);
+ int ret = 0;
+ u32 i;
+
+ for (i = 0; i < indio_dev->num_channels; i++) {
+ ret = ds4424_set_value(indio_dev, data->save[i],
+ &indio_dev->channels[i]);
+ if (ret < 0)
+ return ret;
+ }
+ return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(ds4424_pm_ops, ds4424_suspend, ds4424_resume);
+
+static const struct iio_info ds4424_info = {
+ .read_raw = ds4424_read_raw,
+ .write_raw = ds4424_write_raw,
+ .driver_module = THIS_MODULE,
+};
+
+#ifdef CONFIG_OF
+static int ds4424_parse_dt(struct iio_dev *indio_dev)
+{
+ int ret;
+ int len;
+ int count;
+ struct property *prop;
+ struct ds4424_data *data = iio_priv(indio_dev);
+ struct device_node *node = indio_dev->dev.of_node;
+
+ if (!node) {
+ pr_info("%s:%d ds4424 DT not found\n", __func__, __LINE__);
+ return -ENODEV;
+ }
+
+ prop = of_find_property(node, "maxim,rfs-resistors-ohms", &len);
+ if (!prop) {
+ pr_err("ds4424 maxim,rfs-resistor not found in DT.\n");
+ return -EINVAL;
+ }
+
+ if (len != (DS4424_MAX_DAC_CHANNELS * sizeof(uint32_t))) {
+ pr_err("ds4424 maxim,rfs-resistor length in DT not valid.\n");
+ return -EINVAL;
+ }
+
+ ret = of_property_read_u32_array(node, "maxim,rfs-resistors-ohms",
+ data->rfs_res, DS4424_MAX_DAC_CHANNELS);
+ if (ret < 0) {
+ pr_err("ds4424 reading maxim,rfs-resistors from DT failed.\n");
+ return ret;
+ }
+
+ pr_info("ds4424 maxim,rfs-resistors: %d, %d, %d, %d\n",
+ data->rfs_res[0], data->rfs_res[1],
+ data->rfs_res[2], data->rfs_res[3]);
+
+ count = of_property_count_strings(node, "maxim,dac-iio-map");
+ if (count < 0) {
+ pr_info("ds4424 maxim,dac-iio-map not found in DT\n");
+ return count;
+ }
+
+ if (count != DS4424_MAX_DAC_CHANNELS * 3 &&
+ count != DS4424_MAX_DAC_CHANNELS * 3) {
+ pr_info("ds4424 maxim,dac-iio-map in DT not valid.\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+#else
+static int ds4424_parse_dt(struct iio_dev *indio_dev)
+{
+ return -ENODEV;
+}
+#endif
+
+static int ds4424_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ const struct ds4424_pdata *pdata;
+ struct ds4424_data *data;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev) {
+ dev_err(&client->dev, "iio dev alloc failed.\n");
+ return -ENOMEM;
+ }
+
+ data = iio_priv(indio_dev);
+ i2c_set_clientdata(client, indio_dev);
+ data->client = client;
+ indio_dev->name = id->name;
+ indio_dev->dev.of_node = client->dev.of_node;
+ indio_dev->dev.parent = &client->dev;
+
+ if (client->dev.of_node) {
+ indio_dev->dev.of_node = client->dev.of_node;
+ ret = ds4424_parse_dt(indio_dev);
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "%s - of_node error\n", __func__);
+ return -EINVAL;
+ }
+ } else {
+ pdata = client->dev.platform_data;
+ if (!pdata) {
+ dev_err(&client->dev,
+ "dts/platform data not found.\n");
+ pdata = &ds4424_pdata;
+ }
+
+ pdata = client->dev.platform_data;
+ memcpy(data->rfs_res, pdata->rfs_res,
+ sizeof(uint32_t) * DS4424_MAX_DAC_CHANNELS);
+ }
+
+ data->vcc_reg = devm_regulator_get(&client->dev, "vcc");
+ if (IS_ERR(data->vcc_reg)) {
+ ret = PTR_ERR(data->vcc_reg);
+ dev_err(&client->dev,
+ "Failed to get vcc-supply regulator: %d\n", ret);
+ return ret;
+ }
+
+ mutex_init(&data->lock);
+ ret = regulator_enable(data->vcc_reg);
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "Unable to enable the regulator.\n");
+ return ret;
+ }
+
+ usleep_range(1000, 1200);
+ ret = ds4424_verify_chip(indio_dev);
+ if (ret < 0)
+ return -ENXIO;
+
+ switch (id->driver_data) {
+ case ID_DS4422:
+ indio_dev->num_channels = DS4422_MAX_DAC_CHANNELS;
+ break;
+ case ID_DS4424:
+ indio_dev->num_channels = DS4424_MAX_DAC_CHANNELS;
+ break;
+ default:
+ dev_err(&client->dev,
+ "ds4424: Invalid chip id.\n");
+ indio_dev->num_channels = DS4424_MAX_DAC_CHANNELS;
+ break;
+ }
+
+ indio_dev->channels = ds4424_channels;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &ds4424_info;
+
+ ret = iio_map_array_register(indio_dev, ds4424_pdata.dac_iio_map);
+ if (ret < 0)
+ goto err_iio_map_register;
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "iio_device_register failed. ret: %d\n", ret);
+ goto err_iio_dev_register;
+ }
+
+ return ret;
+
+err_iio_map_register:
+ regulator_disable(data->vcc_reg);
+
+err_iio_dev_register:
+ iio_map_array_unregister(indio_dev);
+ return ret;
+}
+
+static int ds4424_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct ds4424_data *data = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ iio_map_array_unregister(indio_dev);
+ regulator_disable(data->vcc_reg);
+
+ return 0;
+}
+
+static const struct i2c_device_id ds4424_id[] = {
+ { "ds4422", ID_DS4422 },
+ { "ds4424", ID_DS4424 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ds4424_id);
+
+static const struct of_device_id ds4424_of_match[] = {
+ { .compatible = "maxim,ds4422" },
+ { .compatible = "maxim,ds4424" },
+ { }
+};
+
+MODULE_DEVICE_TABLE(of, ds4424_of_match);
+
+static struct i2c_driver ds4424_driver = {
+ .driver = {
+ .name = "ds4424",
+ .of_match_table = ds4424_of_match,
+ .pm = &ds4424_pm_ops,
+ },
+ .probe = ds4424_probe,
+ .remove = ds4424_remove,
+ .id_table = ds4424_id,
+};
+module_i2c_driver(ds4424_driver);
+
+MODULE_DESCRIPTION("Maxim DS4424 DAC Driver");
+MODULE_AUTHOR("Ismail H. Kose <ismail.kose@maximintegrated.com>");
+MODULE_AUTHOR("Vishal Sood <vishal.sood@maximintegrated.com>");
+MODULE_AUTHOR("David Jung <david.jung@maximintegrated.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/iio/dac/ds4424.h b/include/linux/iio/dac/ds4424.h
new file mode 100644
index 000000000000..2c814118df38
--- /dev/null
+++ b/include/linux/iio/dac/ds4424.h
@@ -0,0 +1,24 @@
+/*
+ * Maxim Integrated
+ * 7-bit, Multi-Channel Sink/Source Current DAC Driver
+ * Copyright (C) 2017 Maxim Integrated
+ *
+ * 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.
+ */
+
+#ifndef IIO_DAC_DS4424_H_
+#define IIO_DAC_DS4424_H_
+#include <linux/iio/iio.h>
+#include <linux/iio/machine.h>
+
+#define DS4422_MAX_DAC_CHANNELS 2
+#define DS4424_MAX_DAC_CHANNELS 4
+
+struct ds4424_pdata {
+ const char *vcc_supply_name;
+ uint32_t rfs_res[DS4424_MAX_DAC_CHANNELS];
+ struct iio_map *dac_iio_map;
+};
+#endif /* IIO_DAC_DS4424_H_ */
--
2.11.0
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