Add DAC driver support for Vybrid SoC

Hello,

This patchset adds support for the DAC peripheral on Vybrid SoC. Patchset is based on top of shawn's for-next branch and has been tested on a Toradex Colibri VF50 module.

@Jonathan
I kept the IIO_SHARED_BY_DIR instead of using IIO_SHARED_BY_ALL since this gives "out_conversion_mode" allowing me to distinguish this in the ABI documentation, that this is explicitly for the DAC.

Since 4.5-rc4 was released recently and assuming this makes it with this or next version, I assumed the target kernel version would be 4.6 and used that in ABI documentation.

Feedbacks and comments most welcome.

Changes since v2:
1. Add dependencies on OF and HAS_IOMEM in Kconfig
2. Fix ordering of disabling DAC and calling iio unregister

Changes since v1:
1. Fix return type of vf610_dac_init function
2. Document conversion modes in sysfs-bus-iio-vf610
3. Remove "indexed" specification from iio_chan_spec
4. Use "return" directly from default case in switch
5. Remove DRIVER_NAME
6. Call vf610_dac_init before iio device registration
7. Define and use vf610_dac_exit function in remove and suspend

v2 of the patchset
http://www.spinics.net/lists/arm-kernel/msg482839.html

v1 of the patchset:
http://www.spinics.net/lists/arm-kernel/msg481190.html

Thanks & Regards,
Sanchayan Maity.

Sanchayan Maity (2):
ARM: dts: vfxxx: Add DAC node for Vybrid SoC
iio: dac: vf610_dac: Add IIO DAC driver for Vybrid SoC

 Documentation/ABI/testing/sysfs-bus-iio-vf610      |   9 +
 .../devicetree/bindings/iio/dac/vf610-dac.txt      |  20 ++
 arch/arm/boot/dts/vfxxx.dtsi                       |  18 ++
 drivers/iio/dac/Kconfig                            |  10 +
 drivers/iio/dac/Makefile                           |   1 +
 drivers/iio/dac/vf610_dac.c                        | 298 +++++++++++++++++++++
 6 files changed, 356 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/dac/vf610-dac.txt
 create mode 100644 drivers/iio/dac/vf610_dac.c

2.7.1

Add a device tree node entry for DAC peripheral on Vybrid SoC.

---
 arch/arm/boot/dts/vfxxx.dtsi | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

index a5f07e3..8238069 100644
@@ -602,6 +602,24 @@
 				status = "disabled";
 			};
 
+			dac0: dac at 400cc000 {
+				compatible = "fsl,vf610-dac";
+				reg = <0x400cc000 1000>;
+				interrupts = <55 IRQ_TYPE_LEVEL_HIGH>;
+				clock-names = "dac";
+				clocks = <&clks VF610_CLK_DAC0>;
+				status = "disabled";
+			};
+
+			dac1: dac at 400cd000 {
+				compatible = "fsl,vf610-dac";
+				reg = <0x400cd000 1000>;
+				interrupts = <56 IRQ_TYPE_LEVEL_HIGH>;
+				clock-names = "dac";
+				clocks = <&clks VF610_CLK_DAC1>;
+				status = "disabled";
+			};
+
 			fec0: ethernet at 400d0000 {
 				compatible = "fsl,mvf600-fec";
 				reg = <0x400d0000 0x1000>;

2.7.1

Add driver support for DAC peripheral on Vybrid SoC.

---
 Documentation/ABI/testing/sysfs-bus-iio-vf610      |   9 +
 .../devicetree/bindings/iio/dac/vf610-dac.txt      |  20 ++
 drivers/iio/dac/Kconfig                            |  10 +
 drivers/iio/dac/Makefile                           |   1 +
 drivers/iio/dac/vf610_dac.c                        | 298 +++++++++++++++++++++
 5 files changed, 338 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/dac/vf610-dac.txt
 create mode 100644 drivers/iio/dac/vf610_dac.c

index ecbc1f4..308a675 100644
@@ -5,3 +5,12 @@ Description:
 		Specifies the hardware conversion mode used. The three
 		available modes are "normal", "high-speed" and "low-power",
 		where the last is the default mode.
+
+
+What:		/sys/bus/iio/devices/iio:deviceX/out_conversion_mode
+KernelVersion:	4.6
+Contact:	linux-iio at vger.kernel.org
+Description:
+		Specifies the hardware conversion mode used within DAC.
+		The two available modes are "high-power" and "low-power",
+		where "low-power" mode is the default mode.

new file mode 100644
index 0000000..20c6c7a
@@ -0,0 +1,20 @@
+Freescale vf610 Digital to Analog Converter bindings
+
+The devicetree bindings are for the new DAC driver written for
+vf610 SoCs from Freescale.
+
+Required properties:
+- compatible: Should contain "fsl,vf610-dac"
+- reg: Offset and length of the register set for the device
+- interrupts: Should contain the interrupt for the device
+- clocks: The clock is needed by the DAC controller
+- clock-names: Must contain "dac" matching entry in the clocks property.
+
+Example:
+dac0: dac at 400cc000 {
+	compatible = "fsl,vf610-dac";
+	reg = <0x400cc000 0x1000>;
+	interrupts = <55 IRQ_TYPE_LEVEL_HIGH>;
+	clock-names = "dac";
+	clocks = <&clks VF610_CLK_DAC0>;
+};

index e701e28..75e9708 100644
@@ -196,4 +196,14 @@ config MCP4922
 	  To compile this driver as a module, choose M here: the module
 	  will be called mcp4922.
 
+config VF610_DAC
+	tristate "Vybrid vf610 DAC driver"
+	depends on OF
+	depends on HAS_IOMEM
+	help
+	  Say yes here to support Vybrid board digital-to-analog converter.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called vf610_dac.
+
 endmenu

index 63ae056..93feb27 100644
@@ -21,3 +21,4 @@ obj-$(CONFIG_MAX517) += max517.o
 obj-$(CONFIG_MAX5821) += max5821.o
 obj-$(CONFIG_MCP4725) += mcp4725.o
 obj-$(CONFIG_MCP4922) += mcp4922.o
+obj-$(CONFIG_VF610_DAC) += vf610_dac.o

2.7.1

For the binding:

Applied to the togreg branch of iio.git - initially pushed out as testing for the autobuilders to play with it.

Note the dts change probably wants to go via the relevant arch trees. I can take it with an appropriate ack if not.

Jonathan

Hello,

Thanks Jonathan.

Generally shawn picks up the device tree changes once the driver makes it to his for-next branch. I will ping shawn to pick this up once the driver lands in shawn's for-next branch.

Regards,
Sanchayan.

For such device enabling which does no harm on my tree, i.e. no regression or breakage, I will be happy to take it once driver part gets applied, so that we do not need to wait for another release cycle to get it work.

I applied dts patch, thanks.

Shawn