staging:iio:adc: Add SPEAr ADC driver

This patch implements the basic single data conversion support for
the SPEAr600 SoC ADC. The register layout of SPEAr600 differs a bit
from other SPEAr SoC variants (e.g. SPEAr3xx). These differences are
handled via DT compatible testing. Resulting in a multi-arch binary.

This driver is currently tested only on SPEAr600. Future patches may add
support for other SoC variants (SPEAr3xx) and features like software
buffer or DMA.

Signed-off-by: Stefan Roese <sr@denx.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@st.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/staging/iio/adc/spear-adc.txt b/Documentation/devicetree/bindings/staging/iio/adc/spear-adc.txt
new file mode 100644
index 000000000000..02ea23a63f20
--- /dev/null
+++ b/Documentation/devicetree/bindings/staging/iio/adc/spear-adc.txt
@@ -0,0 +1,26 @@
+* ST SPEAr ADC device driver
+
+Required properties:
+- compatible: Should be "st,spear600-adc"
+- reg: Address and length of the register set for the device
+- interrupt-parent: Should be the phandle for the interrupt controller
+  that services interrupts for this device
+- interrupts: Should contain the ADC interrupt
+- sampling-frequency: Default sampling frequency
+
+Optional properties:
+- vref-external: External voltage reference in milli-volts. If omitted
+  the internal voltage reference will be used.
+- average-samples: Number of samples to generate an average value. If
+  omitted, single data conversion will be used.
+
+Examples:
+
+        adc: adc@d8200000 {
+                compatible = "st,spear600-adc";
+                reg = <0xd8200000 0x1000>;
+                interrupt-parent = <&vic1>;
+                interrupts = <6>;
+                sampling-frequency = <5000000>;
+                vref-external = <2500>; /* 2.5V VRef */
+        };