1 files changed, 154 insertions, 23 deletions

diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c
index a612ec766d96..1f4a48e6a82c 100644
--- a/drivers/iio/dac/mcp4725.c
+++ b/drivers/iio/dac/mcp4725.c
@@ -12,14 +12,13 @@
  * 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)
- *
- * writing the DAC value to EEPROM is not supported
  */
 
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/i2c.h>
 #include <linux/err.h>
+#include <linux/delay.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -32,15 +31,19 @@ struct mcp4725_data {
 	struct i2c_client *client;
 	u16 vref_mv;
 	u16 dac_value;
+	bool powerdown;
+	unsigned powerdown_mode;
 };
 
-#ifdef CONFIG_PM_SLEEP
 static int mcp4725_suspend(struct device *dev)
 {
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct mcp4725_data *data = iio_priv(indio_dev);
 	u8 outbuf[2];
 
-	outbuf[0] = 0x3 << 4; /* power-down bits, 500 kOhm resistor */
+	outbuf[0] = (data->powerdown_mode + 1) << 4;
 	outbuf[1] = 0;
+	data->powerdown = true;
 
 	return i2c_master_send(to_i2c_client(dev), outbuf, 2);
 }
@@ -54,16 +57,150 @@ static int mcp4725_resume(struct device *dev)
 	/* restore previous DAC value */
 	outbuf[0] = (data->dac_value >> 8) & 0xf;
 	outbuf[1] = data->dac_value & 0xff;
+	data->powerdown = false;
 
 	return i2c_master_send(to_i2c_client(dev), 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,
+	},
+	IIO_ENUM("powerdown_mode", false, &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,
@@ -72,6 +209,7 @@ static const struct iio_chan_spec mcp4725_channel = {
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 	.scan_type	= IIO_ST('u', 12, 16, 0),
+	.ext_info	= mcp4725_ext_info,
 };
 
 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
@@ -138,6 +276,7 @@ static int mcp4725_write_raw(struct iio_dev *indio_dev,
 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,
 };
 
@@ -148,19 +287,17 @@ static int mcp4725_probe(struct i2c_client *client,
 	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");
-		err = -EINVAL;
-		goto exit;
+		return -EINVAL;
 	}
 
-	indio_dev = iio_device_alloc(sizeof(*data));
-	if (indio_dev == NULL) {
-		err = -ENOMEM;
-		goto exit;
-	}
+	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;
@@ -177,31 +314,25 @@ static int mcp4725_probe(struct i2c_client *client,
 	err = i2c_master_recv(client, inbuf, 3);
 	if (err < 0) {
 		dev_err(&client->dev, "failed to read DAC value");
-		goto exit_free_device;
+		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);
 
 	err = iio_device_register(indio_dev);
 	if (err)
-		goto exit_free_device;
+		return err;
 
 	dev_info(&client->dev, "MCP4725 DAC registered\n");
 
 	return 0;
-
-exit_free_device:
-	iio_device_free(indio_dev);
-exit:
-	return err;
 }
 
 static int mcp4725_remove(struct i2c_client *client)
 {
-	struct iio_dev *indio_dev = i2c_get_clientdata(client);
-
-	iio_device_unregister(indio_dev);
-	iio_device_free(indio_dev);
-
+	iio_device_unregister(i2c_get_clientdata(client));
 	return 0;
 }