iio: xilinx-xadc: Add basic support for Ultrascale System Monitor

The xilinx-xadc IIO driver currently has support for the XADC in the Xilinx
7 series FPGAs. The system-monitor is the equivalent to the XADC in the
Xilinx UltraScale and UltraScale+ FPGAs.

The IP designers did a good job at maintaining backwards compatibility and
only minor changes are required to add basic support for the system-monitor
core.

The non backwards compatible changes are:
  * Register map offset was moved from 0x200 to 0x400
  * Only one ADC compared to two in the XADC
  * 10 bit ADC instead of 12 bit ADC
  * Two of the channels monitor different supplies

Add the necessary logic to accommodate these changes to support the
system-monitor in the XADC driver.

Note that this patch does not include support for some new features found
in the system-monitor like additional alarms, user supply monitoring and
secondary system-monitor access. This might be added at a later time.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Anand Ashok Dumbre <anandash@xilinx.com>
Reviewed-by: Anand Ashok Dumbre <anandash@xilinx.com>
Link: https://lore.kernel.org/r/20200922134624.13191-2-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/iio/adc/xilinx-xadc.h b/drivers/iio/adc/xilinx-xadc.h
index 25abed9c0285..8b80195725e9 100644
--- a/drivers/iio/adc/xilinx-xadc.h
+++ b/drivers/iio/adc/xilinx-xadc.h
@@ -70,6 +70,11 @@ struct xadc {
 	int irq;
 };
 
+enum xadc_type {
+	XADC_TYPE_S7, /* Series 7 */
+	XADC_TYPE_US, /* UltraScale and UltraScale+ */
+};
+
 struct xadc_ops {
 	int (*read)(struct xadc *xadc, unsigned int reg, uint16_t *val);
 	int (*write)(struct xadc *xadc, unsigned int reg, uint16_t val);
@@ -80,6 +85,7 @@ struct xadc_ops {
 	irqreturn_t (*interrupt_handler)(int irq, void *devid);
 
 	unsigned int flags;
+	enum xadc_type type;
 };
 
 static inline int _xadc_read_adc_reg(struct xadc *xadc, unsigned int reg,