On 6/6/2012 10:40 PM, Peter Meerwald wrote:
v3:
* move from staging to drivers/iio
* switch to chan_spec
* dev_get_drvdata() -> dev_to_iio_dev()
* annotate probe() and remove() with __devinit and __devexit
v2 (based on comments from Jonathan Cameron and Lars-Peter Clausen):
* did NOT switch to chan_spec yet
* rebase to staging-next tree, update iio header locations
* dropped dac.h #include, not needed
* strict_strtol() -> kstrtol()
* call iio_device_unregister() in remove()
* everything in one patch
That's what I like. A driver short enough to review whilst having a
coffee before starting work at the day job ;)
Couple of comments. Only important one is I don't think that
the iio_dev pointer in your *_data structure is used anywhere...
Jonathan
Signed-off-by: Peter Meerwald<pmeerw@xxxxxxxxxx>
---
drivers/iio/dac/Kconfig | 11 ++
drivers/iio/dac/Makefile | 1 +
drivers/iio/dac/mcp4725.c | 228 +++++++++++++++++++++++++++++++++++++++
include/linux/iio/dac/mcp4725.h | 16 +++
4 files changed, 256 insertions(+)
create mode 100644 drivers/iio/dac/mcp4725.c
create mode 100644 include/linux/iio/dac/mcp4725.h
diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index a626f03..92fb3a0 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -118,4 +118,15 @@ config MAX517
This driver can also be built as a module. If so, the module
will be called max517.
+config MCP4725
+ tristate "MCP4725 DAC driver"
+ depends on I2C
+ ---help---
+ Say Y here if you want to build a driver for the Microchip
+ MCP 4725 12-bit digital-to-analog converter (DAC) with I2C
+ interface.
+
+ To compile this driver as a module, choose M here: the module
+ will be called mcp4725.
+
endmenu
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index 8ab1d26..9ea3cee 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_AD5764) += ad5764.o
obj-$(CONFIG_AD5791) += ad5791.o
obj-$(CONFIG_AD5686) += ad5686.o
obj-$(CONFIG_MAX517) += max517.o
+obj-$(CONFIG_MCP4725) += mcp4725.o
diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c
new file mode 100644
index 0000000..244ccf6
--- /dev/null
+++ b/drivers/iio/dac/mcp4725.c
@@ -0,0 +1,228 @@
+/*
+ * mcp4725.c - Support for Microchip MCP4725
+ *
+ * Copyright (C) 2012 Peter Meerwald<pmeerw@xxxxxxxxxx>
+ *
+ * Based on max517 by Roland Stigge<stigge@xxxxxxxxx>
+ *
+ * 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)
+ *
+ * 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/iio/iio.h>
+#include<linux/iio/sysfs.h>
+
+#include "mcp4725.h"
+
+#define MCP4725_DRV_NAME "mcp4725"
+
+struct mcp4725_data {
+ struct iio_dev *indio_dev;
I can't immediately see whta this iio_dev pointer is for?
Don't think it is even set anywhere.
+ struct i2c_client *client;
+ unsigned short vref_mv;
+ unsigned short dac_value;
Rather than a short, I'd use a defined length type
u16 probably. Doesn't matter much though.
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int mcp4725_suspend(struct device *dev)
+{
+ u8 outbuf[2];
+
+ outbuf[0] = 0x3<< 4; /* power-down bits, 500 kOhm resistor */
+ outbuf[1] = 0;
+
+ return i2c_master_send(to_i2c_client(dev),&outbuf, 2);
+}
+
+static int mcp4725_resume(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct mcp4725_data *data = iio_priv(indio_dev);
+ u8 outbuf[2];
+
+ /* restore previous DAC value */
+ outbuf[0] = (data->dac_value>> 8)& 0xf;
+ outbuf[1] = data->dac_value& 0xff;
+
+ return i2c_master_send(to_i2c_client(dev),&outbuf, 2);
+}
+
+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 const struct iio_chan_spec mcp4725_channel = {
+ .type = IIO_VOLTAGE,
+ .indexed = 1,
+ .output = 1,
+ .channel = 0,
+ .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
+ IIO_CHAN_INFO_SCALE_SHARED_BIT,
+ .scan_type = IIO_ST('u', 12, 16, 0),
Arguably this acts as documentation, but personally I'd not bother
specifying scan_type as output drivers don't currently use them.
+};
+
+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);
+ unsigned long scale_uv;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ *val = data->dac_value;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ scale_uv = (data->vref_mv * 1000)>> 12;
+ *val = scale_uv / 1000000;
+ *val2 = scale_uv % 1000000;
+ return IIO_VAL_INT_PLUS_MICRO;
+ }
+ 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);
Convention would be to probably not update the cache on a
failure. But then if we get a failiure the state is unknown
anyway so what the heck...
+ 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,
+ .driver_module = THIS_MODULE,
+};
+
+static int __devinit 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];
+ int err;
+
+ if (!platform_data || !platform_data->vref_mv) {
+ dev_err(&client->dev, "invalid platform data");
+ err = -EINVAL;
+ goto exit;
+ }
+
+ indio_dev = iio_device_alloc(sizeof(*data));
+ if (indio_dev == NULL) {
+ err = -ENOMEM;
+ goto exit;
+ }
+ 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");
+ goto exit_free_device;
+ }
+ data->dac_value = (inbuf[1]<< 4) | (inbuf[2]>> 4);
+
+ err = iio_device_register(indio_dev);
+ if (err)
+ goto exit_free_device;
+
+ dev_info(&client->dev, "MCP4725 DAC registered\n");
+
+ return 0;
+
+exit_free_device:
+ iio_device_free(indio_dev);
+exit:
+ return err;
+}
+
+static int __devexit 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);
+
+ 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 = __devexit_p(mcp4725_remove),
+ .id_table = mcp4725_id,
+};
+module_i2c_driver(mcp4725_driver);
+
+MODULE_AUTHOR("Peter Meerwald<pmeerw@xxxxxxxxxx>");
+MODULE_DESCRIPTION("MCP4725 12-bit DAC");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/iio/dac/mcp4725.h b/include/linux/iio/dac/mcp4725.h
new file mode 100644
index 0000000..91530e6
--- /dev/null
+++ b/include/linux/iio/dac/mcp4725.h
@@ -0,0 +1,16 @@
+/*
+ * MCP4725 DAC driver
+ *
+ * Copyright (C) 2012 Peter Meerwald<pmeerw@xxxxxxxxxx>
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#ifndef IIO_DAC_MCP4725_H_
+#define IIO_DAC_MCP4725_H_
+
+struct mcp4725_platform_data {
+ u16 vref_mv;
+};
+
+#endif /* IIO_DAC_MCP4725_H_ */
--
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