1 files changed, 349 insertions, 0 deletions

diff --git a/kernel/drivers/iio/dac/mcp4725.c b/kernel/drivers/iio/dac/mcp4725.c
new file mode 100644
index 000000000..43d145884
--- /dev/null
+++ b/kernel/drivers/iio/dac/mcp4725.c
@@ -0,0 +1,349 @@
+/*
+ * mcp4725.c - Support for Microchip MCP4725
+ *
+ * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
+ *
+ * Based on max517 by Roland Stigge <stigge@antcom.de>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License.  See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
+ * (7-bit I2C slave address 0x60, the three LSBs can be configured in
+ * hardware)
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#include <linux/iio/dac/mcp4725.h>
+
+#define MCP4725_DRV_NAME "mcp4725"
+
+struct mcp4725_data {
+	struct i2c_client *client;
+	u16 vref_mv;
+	u16 dac_value;
+	bool powerdown;
+	unsigned powerdown_mode;
+};
+
+static int mcp4725_suspend(struct device *dev)
+{
+	struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
+		to_i2c_client(dev)));
+	u8 outbuf[2];
+
+	outbuf[0] = (data->powerdown_mode + 1) << 4;
+	outbuf[1] = 0;
+	data->powerdown = true;
+
+	return i2c_master_send(data->client, outbuf, 2);
+}
+
+static int mcp4725_resume(struct device *dev)
+{
+	struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
+		to_i2c_client(dev)));
+	u8 outbuf[2];
+
+	/* restore previous DAC value */
+	outbuf[0] = (data->dac_value >> 8) & 0xf;
+	outbuf[1] = data->dac_value & 0xff;
+	data->powerdown = false;
+
+	return i2c_master_send(data->client, outbuf, 2);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
+#define MCP4725_PM_OPS (&mcp4725_pm_ops)
+#else
+#define MCP4725_PM_OPS NULL
+#endif
+
+static ssize_t mcp4725_store_eeprom(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct mcp4725_data *data = iio_priv(indio_dev);
+	int tries = 20;
+	u8 inoutbuf[3];
+	bool state;
+	int ret;
+
+	ret = strtobool(buf, &state);
+	if (ret < 0)
+		return ret;
+
+	if (!state)
+		return 0;
+
+	inoutbuf[0] = 0x60; /* write EEPROM */
+	inoutbuf[1] = data->dac_value >> 4;
+	inoutbuf[2] = (data->dac_value & 0xf) << 4;
+
+	ret = i2c_master_send(data->client, inoutbuf, 3);
+	if (ret < 0)
+		return ret;
+	else if (ret != 3)
+		return -EIO;
+
+	/* wait for write complete, takes up to 50ms */
+	while (tries--) {
+		msleep(20);
+		ret = i2c_master_recv(data->client, inoutbuf, 3);
+		if (ret < 0)
+			return ret;
+		else if (ret != 3)
+			return -EIO;
+
+		if (inoutbuf[0] & 0x80)
+			break;
+	}
+
+	if (tries < 0) {
+		dev_err(&data->client->dev,
+			"mcp4725_store_eeprom() failed, incomplete\n");
+		return -EIO;
+	}
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
+
+static struct attribute *mcp4725_attributes[] = {
+	&iio_dev_attr_store_eeprom.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group mcp4725_attribute_group = {
+	.attrs = mcp4725_attributes,
+};
+
+static const char * const mcp4725_powerdown_modes[] = {
+	"1kohm_to_gnd",
+	"100kohm_to_gnd",
+	"500kohm_to_gnd"
+};
+
+static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan)
+{
+	struct mcp4725_data *data = iio_priv(indio_dev);
+
+	return data->powerdown_mode;
+}
+
+static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan, unsigned mode)
+{
+	struct mcp4725_data *data = iio_priv(indio_dev);
+
+	data->powerdown_mode = mode;
+
+	return 0;
+}
+
+static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
+	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
+{
+	struct mcp4725_data *data = iio_priv(indio_dev);
+
+	return sprintf(buf, "%d\n", data->powerdown);
+}
+
+static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
+	 uintptr_t private, const struct iio_chan_spec *chan,
+	 const char *buf, size_t len)
+{
+	struct mcp4725_data *data = iio_priv(indio_dev);
+	bool state;
+	int ret;
+
+	ret = strtobool(buf, &state);
+	if (ret)
+		return ret;
+
+	if (state)
+		ret = mcp4725_suspend(&data->client->dev);
+	else
+		ret = mcp4725_resume(&data->client->dev);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static const struct iio_enum mcp4725_powerdown_mode_enum = {
+	.items = mcp4725_powerdown_modes,
+	.num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
+	.get = mcp4725_get_powerdown_mode,
+	.set = mcp4725_set_powerdown_mode,
+};
+
+static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
+	{
+		.name = "powerdown",
+		.read = mcp4725_read_powerdown,
+		.write = mcp4725_write_powerdown,
+		.shared = IIO_SEPARATE,
+	},
+	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &mcp4725_powerdown_mode_enum),
+	IIO_ENUM_AVAILABLE("powerdown_mode", &mcp4725_powerdown_mode_enum),
+	{ },
+};
+
+static const struct iio_chan_spec mcp4725_channel = {
+	.type		= IIO_VOLTAGE,
+	.indexed	= 1,
+	.output		= 1,
+	.channel	= 0,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+	.ext_info	= mcp4725_ext_info,
+};
+
+static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
+{
+	struct mcp4725_data *data = iio_priv(indio_dev);
+	u8 outbuf[2];
+	int ret;
+
+	if (val >= (1 << 12) || val < 0)
+		return -EINVAL;
+
+	outbuf[0] = (val >> 8) & 0xf;
+	outbuf[1] = val & 0xff;
+
+	ret = i2c_master_send(data->client, outbuf, 2);
+	if (ret < 0)
+		return ret;
+	else if (ret != 2)
+		return -EIO;
+	else
+		return 0;
+}
+
+static int mcp4725_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2, long mask)
+{
+	struct mcp4725_data *data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		*val = data->dac_value;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = data->vref_mv;
+		*val2 = 12;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	}
+	return -EINVAL;
+}
+
+static int mcp4725_write_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int val, int val2, long mask)
+{
+	struct mcp4725_data *data = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = mcp4725_set_value(indio_dev, val);
+		data->dac_value = val;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static const struct iio_info mcp4725_info = {
+	.read_raw = mcp4725_read_raw,
+	.write_raw = mcp4725_write_raw,
+	.attrs = &mcp4725_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
+static int mcp4725_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct mcp4725_data *data;
+	struct iio_dev *indio_dev;
+	struct mcp4725_platform_data *platform_data = client->dev.platform_data;
+	u8 inbuf[3];
+	u8 pd;
+	int err;
+
+	if (!platform_data || !platform_data->vref_mv) {
+		dev_err(&client->dev, "invalid platform data");
+		return -EINVAL;
+	}
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &mcp4725_info;
+	indio_dev->channels = &mcp4725_channel;
+	indio_dev->num_channels = 1;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	data->vref_mv = platform_data->vref_mv;
+
+	/* read current DAC value */
+	err = i2c_master_recv(client, inbuf, 3);
+	if (err < 0) {
+		dev_err(&client->dev, "failed to read DAC value");
+		return err;
+	}
+	pd = (inbuf[0] >> 1) & 0x3;
+	data->powerdown = pd > 0 ? true : false;
+	data->powerdown_mode = pd ? pd-1 : 2; /* 500kohm_to_gnd */
+	data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
+
+	return iio_device_register(indio_dev);
+}
+
+static int mcp4725_remove(struct i2c_client *client)
+{
+	iio_device_unregister(i2c_get_clientdata(client));
+	return 0;
+}
+
+static const struct i2c_device_id mcp4725_id[] = {
+	{ "mcp4725", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mcp4725_id);
+
+static struct i2c_driver mcp4725_driver = {
+	.driver = {
+		.name	= MCP4725_DRV_NAME,
+		.pm	= MCP4725_PM_OPS,
+	},
+	.probe		= mcp4725_probe,
+	.remove		= mcp4725_remove,
+	.id_table	= mcp4725_id,
+};
+module_i2c_driver(mcp4725_driver);
+
+MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("MCP4725 12-bit DAC");
+MODULE_LICENSE("GPL");