iio: impedance-analyzer: New driver for AD5933/4 Impedance Converter, Network Analyzer

The AD5933 is a high precision impedance converter system solution
that combines an on-board frequency generator with a 12-bit, 1 MSPS,
analog-to-digital converter (ADC). The frequency generator allows an
external complex impedance to be excited with a known frequency.

The response signal from the impedance is sampled by the on-board ADC
and a discrete Fourier transform (DFT) is processed by an on-chip DSP engine.
The DFT algorithm returns a real (R) and imaginary (I) data-word at each
output frequency.

Changes since V1:

Apply list review feedback:
Consistently use poll_time_jiffies.
Use be|le cpu endian helpers where applicable.
Add various comments.

Changes since V2:

Fix KernelVersion tag in Documentation.
Declare ad5933_default_pdata static.
Fix typos.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 28 insertions, 0 deletions

diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.h b/drivers/staging/iio/impedance-analyzer/ad5933.h
new file mode 100644
index 00000000000..b140e42d67c
--- /dev/null
+++ b/drivers/staging/iio/impedance-analyzer/ad5933.h
@@ -0,0 +1,28 @@
+/*
+ * AD5933 AD5934 Impedance Converter, Network Analyzer
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#ifndef IIO_ADC_AD5933_H_
+#define IIO_ADC_AD5933_H_
+
+/*
+ * TODO: struct ad5933_platform_data needs to go into include/linux/iio
+ */
+
+/**
+ * struct ad5933_platform_data - platform specific data
+ * @ext_clk_Hz:         the external clock frequency in Hz, if not set
+ *                      the driver uses the internal clock (16.776 MHz)
+ * @vref_mv:            the external reference voltage in millivolt
+ */
+
+struct ad5933_platform_data {
+        unsigned long                   ext_clk_Hz;
+        unsigned short                  vref_mv;
+};
+
+#endif /* IIO_ADC_AD5933_H_ */