* [PATCH 1/2] iio: adc: xilinx-xadc: Don't clobber preset voltage/temperature thresholds
2023-09-14 21:24 [PATCH 0/2] Xilinx XADC fixes Robert Hancock
@ 2023-09-14 21:24 ` Robert Hancock
2023-09-14 23:45 ` Robert Hancock
2023-09-14 21:24 ` [PATCH 2/2] iio: adc: xilinx-xadc: Correct temperature offset/scale for UltraScale Robert Hancock
1 sibling, 1 reply; 4+ messages in thread
From: Robert Hancock @ 2023-09-14 21:24 UTC (permalink / raw)
To: Jonathan Cameron
Cc: Lars-Peter Clausen, Michal Simek, Anand Ashok Dumbre, linux-iio,
linux-arm-kernel, Robert Hancock
In the probe function, the driver was reading out the thresholds already
set in the core, which can be configured by the user in the Vivado tools
when the FPGA image is built. However, it later clobbered those values
with zero or maximum values. In particular, the overtemperature shutdown
threshold register was overwritten with the max value, which effectively
prevents the FPGA from shutting down when the desired threshold was
eached, potentially risking hardware damage in that case.
Remove this code to leave the preconfigured default threshold values
intact.
Fixes: bdc8cda1d010 ("iio:adc: Add Xilinx XADC driver")
Signed-off-by: Robert Hancock <robert.hancock@calian.com>
---
drivers/iio/adc/xilinx-xadc-core.c | 16 ----------------
1 file changed, 16 deletions(-)
diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c
index dba73300f894..88d523ac7881 100644
--- a/drivers/iio/adc/xilinx-xadc-core.c
+++ b/drivers/iio/adc/xilinx-xadc-core.c
@@ -1429,22 +1429,6 @@ static int xadc_probe(struct platform_device *pdev)
if (ret)
return ret;
- /* Set thresholds to min/max */
- for (i = 0; i < 16; i++) {
- /*
- * Set max voltage threshold and both temperature thresholds to
- * 0xffff, min voltage threshold to 0.
- */
- if (i % 8 < 4 || i == 7)
- xadc->threshold[i] = 0xffff;
- else
- xadc->threshold[i] = 0;
- ret = xadc_write_adc_reg(xadc, XADC_REG_THRESHOLD(i),
- xadc->threshold[i]);
- if (ret)
- return ret;
- }
-
/* Go to non-buffered mode */
xadc_postdisable(indio_dev);
--
2.41.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 2/2] iio: adc: xilinx-xadc: Correct temperature offset/scale for UltraScale
2023-09-14 21:24 [PATCH 0/2] Xilinx XADC fixes Robert Hancock
2023-09-14 21:24 ` [PATCH 1/2] iio: adc: xilinx-xadc: Don't clobber preset voltage/temperature thresholds Robert Hancock
@ 2023-09-14 21:24 ` Robert Hancock
1 sibling, 0 replies; 4+ messages in thread
From: Robert Hancock @ 2023-09-14 21:24 UTC (permalink / raw)
To: Jonathan Cameron
Cc: Lars-Peter Clausen, Michal Simek, Anand Ashok Dumbre, linux-iio,
linux-arm-kernel, Robert Hancock
The driver was previously using offset and scale values for the
temperature sensor readings which were only valid for 7-series devices.
Add per-device-type values for offset and scale and set them appropriately
for each device type.
Note that the values used for the UltraScale family are for UltraScale+
(i.e. the SYSMONE4 primitive) using the internal reference, as that seems
to be the most common configuration and the device tree values Xilinx's
device tree generator produces don't seem to give us anything to tell us
which configuration is used. However, the differences within the UltraScale
family seem fairly minor and it's closer than using the 7-series values
instead in any case.
Fixes: c2b7720a7905 ("iio: xilinx-xadc: Add basic support for Ultrascale System Monitor")
Signed-off-by: Robert Hancock <robert.hancock@calian.com>
---
drivers/iio/adc/xilinx-xadc-core.c | 17 ++++++++++++++---
drivers/iio/adc/xilinx-xadc.h | 2 ++
2 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c
index 88d523ac7881..1c6314dd4d1d 100644
--- a/drivers/iio/adc/xilinx-xadc-core.c
+++ b/drivers/iio/adc/xilinx-xadc-core.c
@@ -456,6 +456,9 @@ static const struct xadc_ops xadc_zynq_ops = {
.interrupt_handler = xadc_zynq_interrupt_handler,
.update_alarm = xadc_zynq_update_alarm,
.type = XADC_TYPE_S7,
+ /* Temp in C = (val * 503.975) / 2**bits - 273.15 */
+ .temp_scale = 503975,
+ .temp_offset = 273150,
};
static const unsigned int xadc_axi_reg_offsets[] = {
@@ -566,6 +569,9 @@ static const struct xadc_ops xadc_7s_axi_ops = {
.interrupt_handler = xadc_axi_interrupt_handler,
.flags = XADC_FLAGS_BUFFERED | XADC_FLAGS_IRQ_OPTIONAL,
.type = XADC_TYPE_S7,
+ /* Temp in C = (val * 503.975) / 2**bits - 273.15 */
+ .temp_scale = 503975,
+ .temp_offset = 273150,
};
static const struct xadc_ops xadc_us_axi_ops = {
@@ -577,6 +583,12 @@ static const struct xadc_ops xadc_us_axi_ops = {
.interrupt_handler = xadc_axi_interrupt_handler,
.flags = XADC_FLAGS_BUFFERED | XADC_FLAGS_IRQ_OPTIONAL,
.type = XADC_TYPE_US,
+ /**
+ * Values below are for UltraScale+ (SYSMONE4) using internal reference.
+ * See https://docs.xilinx.com/v/u/en-US/ug580-ultrascale-sysmon
+ */
+ .temp_scale = 509314,
+ .temp_offset = 280231,
};
static int _xadc_update_adc_reg(struct xadc *xadc, unsigned int reg,
@@ -945,8 +957,7 @@ static int xadc_read_raw(struct iio_dev *indio_dev,
*val2 = bits;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_TEMP:
- /* Temp in C = (val * 503.975) / 2**bits - 273.15 */
- *val = 503975;
+ *val = xadc->ops->temp_scale;
*val2 = bits;
return IIO_VAL_FRACTIONAL_LOG2;
default:
@@ -954,7 +965,7 @@ static int xadc_read_raw(struct iio_dev *indio_dev,
}
case IIO_CHAN_INFO_OFFSET:
/* Only the temperature channel has an offset */
- *val = -((273150 << bits) / 503975);
+ *val = -((xadc->ops->temp_offset << bits) / xadc->ops->temp_scale);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SAMP_FREQ:
ret = xadc_read_samplerate(xadc);
diff --git a/drivers/iio/adc/xilinx-xadc.h b/drivers/iio/adc/xilinx-xadc.h
index 7d78ce698967..3036f4d613ff 100644
--- a/drivers/iio/adc/xilinx-xadc.h
+++ b/drivers/iio/adc/xilinx-xadc.h
@@ -85,6 +85,8 @@ struct xadc_ops {
unsigned int flags;
enum xadc_type type;
+ int temp_scale;
+ int temp_offset;
};
static inline int _xadc_read_adc_reg(struct xadc *xadc, unsigned int reg,
--
2.41.0
^ permalink raw reply related [flat|nested] 4+ messages in thread