[PATCH] staging:iio:Documentation Review simple dummy driver

[Manuel Stahl <manuel.stahl@iis.fraunhofer.de>]

Hi Jonathon,

here are some enhancements from me. Of course you can merge the things you like with the original commit.
Maybe we should call the driver "iio_reference", then it's clear what it's for.

Signed-off-by: Manuel Stahl <manuel.stahl@iis.fraunhofer.de>
---
 drivers/staging/iio/iio_simple_dummy.c |   73 ++++++++++++++++++++++++++++---
 1 files changed, 66 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/iio/iio_simple_dummy.c b/drivers/staging/iio/iio_simple_dummy.c
index 0f22be7..674b585 100644
--- a/drivers/staging/iio/iio_simple_dummy.c
+++ b/drivers/staging/iio/iio_simple_dummy.c
@@ -40,6 +40,13 @@ static const struct iio_dummy_accel_calibscale dummy_scales[] = {
 
 /**
  * iio_dummy_state: device instance specific state.
+ * @dac_val:			cache for dac value
+ * @single_ended_adc_val:	cache for single ended adc value
+ * @differential_adc_val:	cache for differential adc value
+ * @accel_val:			cache for acceleration value
+ * @accel_calibbias:		cache for acceleration calibbias
+ * @accel_calibscale:		cache for acceleration calibscale
+ * @lock:			mutex to access this struct
  */
 struct iio_dummy_state {
 	int dac_val;
@@ -134,6 +141,17 @@ static struct iio_chan_spec iio_dummy_channels[] = {
 		 */
 		(1 << IIO_CHAN_INFO_CALIBBIAS_SEPARATE),
 	},
+	/*
+	 * of course you can also use the IIO_CHAN and IIO_ST macros
+	 */
+#define IIO_DUMMY_ST	IIO_ST('s', 14, 16, 0)
+
+	IIO_CHAN(IIO_GYRO, 1, 0, 0, NULL, 0, IIO_MOD_X, 0,
+		0, 0, IIO_DUMMY_ST, 0),
+	IIO_CHAN(IIO_GYRO, 1, 0, 0, NULL, 0, IIO_MOD_Y, 0,
+		0, 0, IIO_DUMMY_ST, 0),
+	IIO_CHAN(IIO_GYRO, 1, 0, 0, NULL, 0, IIO_MOD_Z, 0,
+		0, 0, IIO_DUMMY_ST, 0),
 };
 
 /**
@@ -178,6 +196,10 @@ static int iio_dummy_read_raw(struct iio_dev *indio_dev,
 			*val = st->accel_val;
 			ret = IIO_VAL_INT;
 			break;
+		case IIO_GYRO:
+			*val = -123; /* return some arbitrary number */
+			ret = IIO_VAL_INT;
+			break;
 		default:
 			break;
 		}
@@ -194,7 +216,7 @@ static int iio_dummy_read_raw(struct iio_dev *indio_dev,
 		ret = IIO_VAL_INT_PLUS_MICRO;
 		break;
 	case (1 << IIO_CHAN_INFO_SCALE_SHARED):
-		/* all differential adc channels -> 0.000001344*/
+		/* all differential adc channels -> 0.000001344 */
 		*val = 0;
 		*val2 = 1344;
 		ret = IIO_VAL_INT_PLUS_NANO;
@@ -281,8 +303,8 @@ static const struct iio_info iio_dummy_info = {
  * iio_dummy_init_device: device instance specific init
  * @indio_dev: the iio device structure
  *
- * Most drivers have one of these to set up default values
- * etc.
+ * Most drivers have one of these to set up default values,
+ * reset the device, etc.
  */
 static int iio_dummy_init_device(struct iio_dev *indio_dev)
 {
@@ -298,6 +320,7 @@ static int iio_dummy_init_device(struct iio_dev *indio_dev)
 
 	return 0;
 }
+
 /**
  * iio_dummy_probe: device instance probe
  * @index: an id number for this instance.
@@ -335,13 +358,15 @@ static int __devinit iio_dummy_probe(int index)
 	 * With hardware:
 	 * Set the parent device.
 	 * indio_dev->dev.parent = &spi->dev;
-	 * indio_dev->dev.parent = &client->dev;
+	 * or
+	 * indio_dev->dev.parent = &i2c->dev;
 	 */
 
 	 /*
 	 * Make the iio_dev struct available to remove function.
 	 * Bus equivalents
-	 * i2c_set_clientdata(client, indio_dev);
+	 * i2c_set_clientdata(i2c, indio_dev);
+	 * or
 	 * spi_set_drvdata(spi, indio_dev);
 	 */
 	iio_dummy_devs[index] = indio_dev;
@@ -368,7 +393,7 @@ static int __devinit iio_dummy_probe(int index)
 	 */
 	indio_dev->info = &iio_dummy_info;
 
-	/* Specify that device provides sysfs type interfaces */
+	/* Specify that device provides sysfs type interfaces only */
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
 	ret = iio_device_register(indio_dev);
@@ -395,7 +420,8 @@ static int iio_dummy_remove(int index)
 	/*
 	 * Get a pointer to the device instance iio_dev structure
 	 * from the bus subsystem. E.g.
-	 * struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	 * struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
+	 * or
 	 * struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	 */
 	struct iio_dev *indio_dev = iio_dummy_devs[index];
@@ -408,6 +434,39 @@ static int iio_dummy_remove(int index)
 	return 0;
 }
 
+/*********************************************************
+ * Example for I2C:
+
+static const struct i2c_device_id iio_dummy_id[] = {
+	{ "dummy", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, iio_dummy_id);
+
+static struct i2c_driver iio_dummy_driver = {
+	.driver = {
+		.owner  = THIS_MODULE,
+		.name	= "iio_dummy",
+	},
+	.id_table	= iio_dummy_id,
+	.probe		= iio_dummy_probe,
+	.remove		= iio_dummy_remove,
+};
+
+static int __init iio_dummy_init(void)
+{
+	return i2c_add_driver(&iio_dummy_driver);
+}
+module_init(iio_dummy_init);
+
+static void __exit iio_dummy_exit(void)
+{
+	i2c_del_driver(&iio_dummy_driver);
+}
+module_exit(iio_dummy_exit);
+ *********************************************************/
+
+
 /**
  * iio_dummy_init: device driver registration
  *
-- 
1.7.2.3