* [PATCH v5 1/5] dt-bindings: iio: adc: add xlnx,versal-sysmon binding
2026-06-08 18:37 [PATCH v5 0/5] iio: adc: add AMD/Xilinx Versal SysMon driver Salih Erim
@ 2026-06-08 18:37 ` Salih Erim
2026-06-08 18:37 ` [PATCH v5 2/5] iio: adc: add Versal SysMon driver Salih Erim
` (3 subsequent siblings)
4 siblings, 0 replies; 9+ messages in thread
From: Salih Erim @ 2026-06-08 18:37 UTC (permalink / raw)
To: jic23, andy
Cc: dlechner, nuno.sa, robh, krzk+dt, conor+dt, conall.ogriofa,
michal.simek, linux, erimsalih, linux-iio, devicetree,
linux-kernel, Salih Erim, Krzysztof Kozlowski
Add devicetree binding for the AMD/Xilinx Versal System Monitor (SysMon).
The Versal SysMon is the successor to the Zynq UltraScale+ AMS block,
providing on-chip voltage and temperature monitoring. The hardware
supports up to 160 supply voltage measurement points and up to 64
temperature satellites distributed across the SoC, with configurable
threshold alarms and oversampling. The device can be accessed via
memory-mapped I/O or via an I2C interface.
Supply and temperature channels are described as child nodes under
container nodes, referencing the standard adc.yaml binding for
channel properties.
Co-developed-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Salih Erim <salih.erim@amd.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
Changes in v5:
- No code changes
Changes in v4:
- Add Reviewed-by tag from Krzysztof Kozlowski
Changes in v3:
- Use single compatible (xlnx,versal-sysmon only), remove
xlnx,versal-sysmon-i2c (Krzysztof)
- Rename supply-channels container to voltage-channels (Krzysztof)
- Use single quotes in patternProperties regex (Krzysztof)
- Drop label description from channel properties (Krzysztof)
- Drop bipolar from channel properties (Krzysztof)
- Remove xlnx,aie-temp property from binding and example (Krzysztof)
Changes in v2:
- Restructured to container nodes (supply-channels, temperature-channels)
with channel@N children referencing adc.yaml
- Added xlnx,versal-sysmon-i2c compatible
- Descriptions rewritten to describe hardware only
- Example simplified to #address-cells = <1>
- Interrupt example uses GIC_SPI/IRQ_TYPE_LEVEL_HIGH constants
- Commit description explains hardware context instead of schema layout
- reg required for both MMIO and I2C, interrupts optional
- Hex unit-addresses (channel@a not channel@10) per DTSpec
- patternProperties regex updated to accept hex digits [0-9a-f]
- Example trimmed to minimal variants (one basic + one bipolar supply,
one AIE temperature channel)
.../bindings/iio/adc/xlnx,versal-sysmon.yaml | 154 ++++++++++++++++++
1 file changed, 154 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/adc/xlnx,versal-sysmon.yaml
diff --git a/Documentation/devicetree/bindings/iio/adc/xlnx,versal-sysmon.yaml b/Documentation/devicetree/bindings/iio/adc/xlnx,versal-sysmon.yaml
new file mode 100644
index 00000000000..1ad58e3d616
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/xlnx,versal-sysmon.yaml
@@ -0,0 +1,154 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) 2022 - 2026, Advanced Micro Devices, Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/xlnx,versal-sysmon.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: AMD/Xilinx Versal System Monitor
+
+maintainers:
+ - Salih Erim <salih.erim@amd.com>
+
+description:
+ The AMD/Xilinx Versal System Monitor (SysMon) is the successor to the
+ Zynq UltraScale+ AMS block. It provides on-chip voltage and temperature
+ monitoring with up to 160 voltage measurement points and up to
+ 64 temperature satellites distributed across the SoC. The hardware
+ supports configurable threshold alarms and oversampling. The device
+ can be accessed via memory-mapped I/O or via an I2C interface.
+
+properties:
+ compatible:
+ const: xlnx,versal-sysmon
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+ '#io-channel-cells':
+ const: 1
+
+ voltage-channels:
+ type: object
+ description:
+ Container for voltage measurement channels.
+
+ properties:
+ '#address-cells':
+ const: 1
+
+ '#size-cells':
+ const: 0
+
+ patternProperties:
+ '^channel@([0-9a-f]|[1-9][0-9a-f])$':
+ $ref: adc.yaml
+
+ description:
+ Measures a voltage rail. The register index and rail
+ name are assigned by the hardware design tool (Vivado).
+
+ properties:
+ reg:
+ minimum: 0
+ maximum: 159
+ description:
+ Voltage measurement register index assigned by the hardware
+ design tool.
+
+ required:
+ - reg
+ - label
+
+ unevaluatedProperties: false
+
+ required:
+ - '#address-cells'
+ - '#size-cells'
+
+ additionalProperties: false
+
+ temperature-channels:
+ type: object
+ description:
+ Container for temperature satellite measurement channels.
+
+ properties:
+ '#address-cells':
+ const: 1
+
+ '#size-cells':
+ const: 0
+
+ patternProperties:
+ '^channel@([1-9a-f]|[1-3][0-9a-f]|40)$':
+ $ref: adc.yaml
+
+ description:
+ Reads a temperature satellite sensor. Each satellite monitors
+ a specific region of the SoC die.
+
+ properties:
+ reg:
+ minimum: 1
+ maximum: 64
+ description:
+ Temperature satellite number (1-based hardware index).
+
+ required:
+ - reg
+ - label
+
+ unevaluatedProperties: false
+
+ required:
+ - '#address-cells'
+ - '#size-cells'
+
+ additionalProperties: false
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+ sysmon@f1270000 {
+ compatible = "xlnx,versal-sysmon";
+ reg = <0xf1270000 0x4000>;
+ interrupts = <GIC_SPI 144 IRQ_TYPE_LEVEL_HIGH>;
+ #io-channel-cells = <1>;
+
+ voltage-channels {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ channel@0 {
+ reg = <0>;
+ label = "vccaux";
+ };
+
+ channel@3 {
+ reg = <3>;
+ label = "vcc_ram";
+ bipolar;
+ };
+ };
+
+ temperature-channels {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ channel@a {
+ reg = <10>;
+ label = "aie-temp-ch1";
+ };
+ };
+ };
--
2.48.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v5 2/5] iio: adc: add Versal SysMon driver
2026-06-08 18:37 [PATCH v5 0/5] iio: adc: add AMD/Xilinx Versal SysMon driver Salih Erim
2026-06-08 18:37 ` [PATCH v5 1/5] dt-bindings: iio: adc: add xlnx,versal-sysmon binding Salih Erim
@ 2026-06-08 18:37 ` Salih Erim
2026-06-08 18:37 ` [PATCH v5 3/5] iio: adc: versal-sysmon: add I2C driver Salih Erim
` (2 subsequent siblings)
4 siblings, 0 replies; 9+ messages in thread
From: Salih Erim @ 2026-06-08 18:37 UTC (permalink / raw)
To: jic23, andy
Cc: dlechner, nuno.sa, robh, krzk+dt, conor+dt, conall.ogriofa,
michal.simek, linux, erimsalih, linux-iio, devicetree,
linux-kernel, Salih Erim
Add the core driver and MMIO platform driver for the AMD/Xilinx Versal
System Monitor (SysMon) block.
The SysMon block resides in the platform management controller (PMC) and
provides on-chip voltage and temperature monitoring through a 10-bit,
200 kSPS ADC. It can monitor up to 160 voltage channels and 64
temperature satellites distributed across the SoC, with a consistent
sample rate of 8 kSPS per channel regardless of how many channels are
enabled.
The driver is split into three compilation units:
- versal-sysmon-core: Channel parsing, IIO registration, read_raw
- versal-sysmon: MMIO platform driver with custom regmap accessors
Voltage results are stored in a 19-bit modified floating-point format
and converted to millivolts. Temperature results are stored in Q8.7
signed fixed-point Celsius format and converted to millicelsius.
The MMIO regmap backend uses a custom reg_write accessor that
automatically unlocks the NPI (NoC programming interface) lock
register before each write, as required by the hardware. The regmap
is configured with fast_io since the underlying MMIO accessors are
safe to call from atomic context.
Co-developed-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Salih Erim <salih.erim@amd.com>
---
Changes in v5:
- Add err.h include to core (IWYU) (Andy)
- Drop (int) cast on MILLI in scale assignment (Andy)
- sign_extend32() instead of (s16) cast for temperature raw (Andy)
- Remove unneeded parentheses in voltage address calculation (Andy)
- Drop NULL checks before fwnode_get_child_node_count (Andy)
- Nested size_add() for overflow-safe allocation (Andy)
- if (ret) instead of if (ret < 0) for fwnode property reads (Andy)
- Remove outer parentheses in satellite address calculation (Andy)
- Loop index declared in for() scope (Andy)
- MMIO: add err.h, types.h includes (IWYU) (Andy)
- Header: remove unused types.h include and struct iio_dev
forward declaration (Andy)
Changes in v4:
- Temperature: RAW + SCALE (IIO_VAL_FRACTIONAL, 1000/128) instead
of PROCESSED (Jonathan)
- Voltage: PROCESSED only, drop RAW (Jonathan)
- Drop scan_type from all channel macros (Jonathan)
- Move __free(fwnode_handle) declarations down to just above use
(Jonathan)
- devm_regmap_init() on one line (Jonathan)
- Lock comment: describe RMW sequences and cached state (Jonathan)
- Remove sysmon_q8p7_to_millicelsius() from this patch; the function
is now introduced in P4 where it is first used
Changes in v3:
- IWYU: add array_size.h, string.h, types.h to core; audit and
fix header and MMIO driver includes (Andy)
- Rename _ext to _name in SYSMON_CHAN_TEMP macro parameter (Andy,
Jonathan)
- Use .info_mask_separate = BIT() style in SYSMON_CHAN_TEMP (Andy)
- Use s16 parameter in sysmon_q8p7_to_millicelsius (Andy)
- Use sign_extend32() in sysmon_supply_rawtoprocessed (Andy)
- Split sysmon_read_raw parameters logically across lines (Andy)
- Remove redundant (int) casts on regval (Andy)
- Split num_supply/num_temp initialization (Andy)
- Use __free(fwnode_handle) cleanup, remove goto err_put (Andy)
- Use size_add() for overflow-safe allocation (Andy)
- Use dev_err_probe() in sysmon_parse_fw error paths (Jonathan)
- Move fwnode_irq_get() to core_probe, remove irq parameter
from bus driver interfaces (Jonathan)
- Use (int)MILLI at call sites, drop SYSMON_MILLI define (Andy,
Jonathan)
- Remove sysmon->dev, sysmon->indio_dev, sysmon->irq from struct;
pass as local variables or use regmap_get_device() (Jonathan)
- Use struct device *dev local in sysmon_platform_probe (Andy)
- Describe protected data in lock comment (Jonathan)
- Add comment explaining RAW+PROCESSED co-exposure (Jonathan)
Changes in v2:
- Split into core (versal-sysmon-core.c) + MMIO platform driver
(versal-sysmon.c) + shared header (versal-sysmon.h)
- Uses regmap API instead of direct readl/writel
- MMIO regmap uses custom callbacks with NPI unlock in write path
- Reverse Christmas Tree variable ordering throughout
- Header include order fixed
- MAINTAINERS entry folded in with wildcard F: pattern
- Kconfig: hidden VERSAL_SYSMON_CORE + VERSAL_SYSMON selects it
- Kconfig/Makefile: alphabetical ordering (VERSAL before VF610)
- Bounds validation on DT reg values
- Named constants replace magic numbers (SYSMON_REG_STRIDE,
SYSMON_SUPPLY_MANTISSA_BITS, SYSMON_MILLI)
- kernel-doc for exported sysmon_core_probe() and sysmon_parse_fw()
- Supply voltage conversion uses proper two's complement sign
extension (s16 cast) matching the hardware specification
- Register offsets sorted by address in header
- Each patch introduces only the defines, fields, and includes
it uses (no dead code in any commit)
- Removed unused linux/limits.h and linux/units.h includes
- Renamed iio_dev_info to sysmon_iio_info
- regmap_write return values checked in probe init path
MAINTAINERS | 7 +
drivers/iio/adc/Kconfig | 20 ++
drivers/iio/adc/Makefile | 2 +
drivers/iio/adc/versal-sysmon-core.c | 285 +++++++++++++++++++++++++++
drivers/iio/adc/versal-sysmon.c | 93 +++++++++
drivers/iio/adc/versal-sysmon.h | 67 +++++++
6 files changed, 474 insertions(+)
create mode 100644 drivers/iio/adc/versal-sysmon-core.c
create mode 100644 drivers/iio/adc/versal-sysmon.c
create mode 100644 drivers/iio/adc/versal-sysmon.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 2fb1c75afd1..46762c8496d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -29216,6 +29216,13 @@ F: Documentation/devicetree/bindings/memory-controllers/xlnx,versal-net-ddrmc5.y
F: drivers/edac/versalnet_edac.c
F: include/linux/cdx/edac_cdx_pcol.h
+XILINX VERSAL SYSMON DRIVER
+M: Salih Erim <salih.erim@amd.com>
+L: linux-iio@vger.kernel.org
+S: Maintained
+F: Documentation/devicetree/bindings/iio/adc/xlnx,versal-sysmon.yaml
+F: drivers/iio/adc/versal-sysmon*
+
XILINX WATCHDOG DRIVER
M: Srinivas Neeli <srinivas.neeli@amd.com>
R: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index a9dedbb8eb4..c7f19057484 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1943,6 +1943,26 @@ config TWL6030_GPADC
This driver can also be built as a module. If so, the module will be
called twl6030-gpadc.
+config VERSAL_SYSMON_CORE
+ tristate
+ select REGMAP
+
+config VERSAL_SYSMON
+ tristate "AMD Versal SysMon driver"
+ depends on ARCH_ZYNQMP || COMPILE_TEST
+ depends on HAS_IOMEM
+ select VERSAL_SYSMON_CORE
+ help
+ Say yes here to have support for the AMD/Xilinx Versal System
+ Monitor (SysMon). This driver provides voltage and temperature
+ monitoring through the IIO subsystem.
+
+ The SysMon measures up to 160 supply voltages and reads up to
+ 64 temperature satellites distributed across the SoC.
+
+ To compile this driver as a module, choose M here: the module
+ will be called versal-sysmon.
+
config VF610_ADC
tristate "Freescale vf610 ADC driver"
depends on HAS_IOMEM
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 097357d146b..d7696b1b157 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -167,6 +167,8 @@ obj-$(CONFIG_TI_TLC4541) += ti-tlc4541.o
obj-$(CONFIG_TI_TSC2046) += ti-tsc2046.o
obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
obj-$(CONFIG_TWL6030_GPADC) += twl6030-gpadc.o
+obj-$(CONFIG_VERSAL_SYSMON_CORE) += versal-sysmon-core.o
+obj-$(CONFIG_VERSAL_SYSMON) += versal-sysmon.o
obj-$(CONFIG_VF610_ADC) += vf610_adc.o
obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
obj-$(CONFIG_XILINX_AMS) += xilinx-ams.o
diff --git a/drivers/iio/adc/versal-sysmon-core.c b/drivers/iio/adc/versal-sysmon-core.c
new file mode 100644
index 00000000000..c7b5eecc93c
--- /dev/null
+++ b/drivers/iio/adc/versal-sysmon-core.c
@@ -0,0 +1,285 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD Versal SysMon core driver
+ *
+ * Copyright (C) 2019 - 2022, Xilinx, Inc.
+ * Copyright (C) 2022 - 2026, Advanced Micro Devices, Inc.
+ */
+
+#include <linux/array_size.h>
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/cleanup.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/units.h>
+
+#include <linux/iio/iio.h>
+
+#include "versal-sysmon.h"
+
+#define SYSMON_CHAN_TEMP(_chan, _address, _name) { \
+ .type = IIO_TEMP, \
+ .indexed = 1, \
+ .address = _address, \
+ .channel = _chan, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .datasheet_name = _name, \
+}
+
+/* Static temperature channels (always present) */
+static const struct iio_chan_spec temp_channels[] = {
+ SYSMON_CHAN_TEMP(0, SYSMON_TEMP_MAX, "temp"),
+ SYSMON_CHAN_TEMP(1, SYSMON_TEMP_MIN, "min"),
+ SYSMON_CHAN_TEMP(2, SYSMON_TEMP_MAX_MAX, "max_max"),
+ SYSMON_CHAN_TEMP(3, SYSMON_TEMP_MIN_MIN, "min_min"),
+};
+
+static void sysmon_supply_rawtoprocessed(int raw_data, int *val)
+{
+ int mantissa, format, exponent;
+
+ mantissa = FIELD_GET(SYSMON_MANTISSA_MASK, raw_data);
+ exponent = SYSMON_SUPPLY_MANTISSA_BITS - FIELD_GET(SYSMON_MODE_MASK, raw_data);
+ format = FIELD_GET(SYSMON_FMT_MASK, raw_data);
+ /*
+ * When format bit is set the mantissa is two's complement
+ * (per hardware spec); sign-extend to int for correct arithmetic.
+ */
+ if (format)
+ mantissa = sign_extend32(mantissa, 15);
+
+ *val = (mantissa * (int)MILLI) >> exponent;
+}
+
+static int sysmon_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct sysmon *sysmon = iio_priv(indio_dev);
+ unsigned int regval;
+ int ret;
+
+ guard(mutex)(&sysmon->lock);
+
+ switch (chan->type) {
+ case IIO_TEMP:
+ if (mask == IIO_CHAN_INFO_SCALE) {
+ /* Q8.7 to millicelsius: raw * 1000 / 128 */
+ *val = MILLI;
+ *val2 = BIT(SYSMON_FRACTIONAL_SHIFT);
+ return IIO_VAL_FRACTIONAL;
+ }
+ if (mask != IIO_CHAN_INFO_RAW)
+ return -EINVAL;
+
+ ret = regmap_read(sysmon->regmap, chan->address, ®val);
+ if (ret)
+ return ret;
+
+ *val = sign_extend32(regval, 15);
+ return IIO_VAL_INT;
+
+ case IIO_VOLTAGE:
+ if (mask != IIO_CHAN_INFO_PROCESSED)
+ return -EINVAL;
+
+ ret = regmap_read(sysmon->regmap,
+ chan->address * SYSMON_REG_STRIDE +
+ SYSMON_SUPPLY_BASE, ®val);
+ if (ret)
+ return ret;
+
+ sysmon_supply_rawtoprocessed(regval, val);
+ return IIO_VAL_INT;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int sysmon_read_label(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ char *label)
+{
+ if (chan->datasheet_name)
+ return sysfs_emit(label, "%s\n", chan->datasheet_name);
+
+ return -EINVAL;
+}
+
+static const struct iio_info sysmon_iio_info = {
+ .read_raw = sysmon_read_raw,
+ .read_label = sysmon_read_label,
+};
+
+/**
+ * sysmon_parse_fw() - Parse firmware nodes and configure IIO channels.
+ * @indio_dev: IIO device instance
+ * @dev: Parent device
+ *
+ * Reads voltage-channels and temperature-channels container nodes from
+ * firmware and builds the IIO channel array. Static temperature channels
+ * are prepended, followed by supply and satellite channels from DT.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+static int sysmon_parse_fw(struct iio_dev *indio_dev, struct device *dev)
+{
+ unsigned int num_supply = 0, num_temp = 0;
+ unsigned int idx, temp_chan_idx, volt_chan_idx;
+ struct iio_chan_spec *sysmon_channels;
+ const char *label;
+ u32 reg;
+ int ret;
+
+ struct fwnode_handle *supply_node __free(fwnode_handle) =
+ device_get_named_child_node(dev, "voltage-channels");
+ num_supply = fwnode_get_child_node_count(supply_node);
+
+ struct fwnode_handle *temp_node __free(fwnode_handle) =
+ device_get_named_child_node(dev, "temperature-channels");
+ num_temp = fwnode_get_child_node_count(temp_node);
+
+ sysmon_channels = devm_kcalloc(dev,
+ size_add(size_add(ARRAY_SIZE(temp_channels),
+ num_supply), num_temp),
+ sizeof(*sysmon_channels), GFP_KERNEL);
+ if (!sysmon_channels)
+ return -ENOMEM;
+
+ /* Static temperature channels first (fixed indices) */
+ idx = 0;
+ memcpy(sysmon_channels, temp_channels, sizeof(temp_channels));
+ idx += ARRAY_SIZE(temp_channels);
+
+ /* Supply channels from DT */
+ fwnode_for_each_child_node_scoped(supply_node, child) {
+ ret = fwnode_property_read_u32(child, "reg", ®);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "missing reg for supply channel\n");
+
+ if (reg > SYSMON_SUPPLY_IDX_MAX)
+ return dev_err_probe(dev, -EINVAL,
+ "supply reg %u exceeds max %u\n",
+ reg, SYSMON_SUPPLY_IDX_MAX);
+
+ ret = fwnode_property_read_string(child, "label", &label);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "missing label for supply channel\n");
+
+ sysmon_channels[idx++] = (struct iio_chan_spec) {
+ .type = IIO_VOLTAGE,
+ .indexed = 1,
+ .address = reg,
+ .info_mask_separate =
+ BIT(IIO_CHAN_INFO_PROCESSED),
+ .datasheet_name = label,
+ };
+ }
+
+ /* Temperature satellite channels from DT */
+ fwnode_for_each_child_node_scoped(temp_node, child) {
+ ret = fwnode_property_read_u32(child, "reg", ®);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "missing reg for temp channel\n");
+
+ if (reg < 1 || reg > SYSMON_TEMP_SAT_MAX)
+ return dev_err_probe(dev, -EINVAL,
+ "temp reg %u out of range [1..%u]\n",
+ reg, SYSMON_TEMP_SAT_MAX);
+
+ ret = fwnode_property_read_string(child, "label", &label);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "missing label for temp channel\n");
+
+ sysmon_channels[idx++] = (struct iio_chan_spec) {
+ .type = IIO_TEMP,
+ .indexed = 1,
+ .address = SYSMON_TEMP_SAT_BASE +
+ (reg - 1) * SYSMON_REG_STRIDE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_shared_by_type =
+ BIT(IIO_CHAN_INFO_SCALE),
+ .datasheet_name = label,
+ };
+ }
+
+ indio_dev->num_channels = idx;
+ indio_dev->info = &sysmon_iio_info;
+
+ /*
+ * Assign per-type sequential channel numbers.
+ * IIO sysfs uses type prefix (in_tempN, in_voltageN)
+ * so numbers only need to be unique within each type.
+ */
+ temp_chan_idx = 0;
+ volt_chan_idx = 0;
+ for (unsigned int idx = 0; idx < indio_dev->num_channels; idx++) {
+ if (sysmon_channels[idx].type == IIO_TEMP)
+ sysmon_channels[idx].channel = temp_chan_idx++;
+ else
+ sysmon_channels[idx].channel = volt_chan_idx++;
+ }
+
+ indio_dev->channels = sysmon_channels;
+
+ return 0;
+}
+
+/**
+ * sysmon_core_probe() - Initialize Versal SysMon core
+ * @dev: Parent device
+ * @regmap: Register map for hardware access
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int sysmon_core_probe(struct device *dev, struct regmap *regmap)
+{
+ struct iio_dev *indio_dev;
+ struct sysmon *sysmon;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*sysmon));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ sysmon = iio_priv(indio_dev);
+ sysmon->regmap = regmap;
+
+ ret = devm_mutex_init(dev, &sysmon->lock);
+ if (ret)
+ return ret;
+
+ /* Disable all interrupts and clear pending status */
+ ret = regmap_write(sysmon->regmap, SYSMON_IDR, SYSMON_INTR_ALL_MASK);
+ if (ret)
+ return ret;
+ ret = regmap_write(sysmon->regmap, SYSMON_ISR, SYSMON_INTR_ALL_MASK);
+ if (ret)
+ return ret;
+
+ indio_dev->name = "versal-sysmon";
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ ret = sysmon_parse_fw(indio_dev, dev);
+ if (ret)
+ return ret;
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+EXPORT_SYMBOL_GPL(sysmon_core_probe);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("AMD Versal SysMon Core Driver");
+MODULE_AUTHOR("Salih Erim <salih.erim@amd.com>");
diff --git a/drivers/iio/adc/versal-sysmon.c b/drivers/iio/adc/versal-sysmon.c
new file mode 100644
index 00000000000..0c2704326a4
--- /dev/null
+++ b/drivers/iio/adc/versal-sysmon.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD Versal SysMon MMIO platform driver
+ *
+ * Copyright (C) 2019 - 2022, Xilinx, Inc.
+ * Copyright (C) 2022 - 2026, Advanced Micro Devices, Inc.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+#include "versal-sysmon.h"
+
+struct sysmon_mmio {
+ void __iomem *base;
+};
+
+static int sysmon_mmio_reg_read(void *context, unsigned int reg,
+ unsigned int *val)
+{
+ struct sysmon_mmio *mmio = context;
+
+ *val = readl(mmio->base + reg);
+ return 0;
+}
+
+static int sysmon_mmio_reg_write(void *context, unsigned int reg,
+ unsigned int val)
+{
+ struct sysmon_mmio *mmio = context;
+
+ /* NPI must be unlocked before any register write except to NPI_LOCK */
+ if (reg != SYSMON_NPI_LOCK)
+ writel(SYSMON_NPI_UNLOCK_CODE, mmio->base + SYSMON_NPI_LOCK);
+ writel(val, mmio->base + reg);
+
+ return 0;
+}
+
+static const struct regmap_config sysmon_mmio_regmap_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = SYSMON_REG_STRIDE,
+ .max_register = SYSMON_MAX_REG,
+ .reg_read = sysmon_mmio_reg_read,
+ .reg_write = sysmon_mmio_reg_write,
+ .fast_io = true,
+};
+
+static int sysmon_platform_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct sysmon_mmio *mmio;
+ struct regmap *regmap;
+
+ mmio = devm_kzalloc(dev, sizeof(*mmio), GFP_KERNEL);
+ if (!mmio)
+ return -ENOMEM;
+
+ mmio->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(mmio->base))
+ return PTR_ERR(mmio->base);
+
+ regmap = devm_regmap_init(dev, NULL, mmio, &sysmon_mmio_regmap_config);
+ if (IS_ERR(regmap))
+ return PTR_ERR(regmap);
+
+ return sysmon_core_probe(dev, regmap);
+}
+
+static const struct of_device_id sysmon_of_match_table[] = {
+ { .compatible = "xlnx,versal-sysmon" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, sysmon_of_match_table);
+
+static struct platform_driver sysmon_platform_driver = {
+ .probe = sysmon_platform_probe,
+ .driver = {
+ .name = "versal-sysmon",
+ .of_match_table = sysmon_of_match_table,
+ },
+};
+module_platform_driver(sysmon_platform_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("AMD Versal SysMon Platform Driver");
+MODULE_AUTHOR("Salih Erim <salih.erim@amd.com>");
diff --git a/drivers/iio/adc/versal-sysmon.h b/drivers/iio/adc/versal-sysmon.h
new file mode 100644
index 00000000000..0c0c89f6e0c
--- /dev/null
+++ b/drivers/iio/adc/versal-sysmon.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * AMD Versal SysMon driver
+ *
+ * Copyright (C) 2019 - 2022, Xilinx, Inc.
+ * Copyright (C) 2022 - 2026, Advanced Micro Devices, Inc.
+ */
+
+#ifndef _VERSAL_SYSMON_H_
+#define _VERSAL_SYSMON_H_
+
+#include <linux/bits.h>
+#include <linux/mutex.h>
+
+struct device;
+struct regmap;
+
+/* Register offsets (sorted by address) */
+#define SYSMON_NPI_LOCK 0x000C
+#define SYSMON_ISR 0x0044
+#define SYSMON_IDR 0x0050
+#define SYSMON_TEMP_MAX 0x1030
+#define SYSMON_TEMP_MIN 0x1034
+#define SYSMON_SUPPLY_BASE 0x1040
+#define SYSMON_TEMP_MIN_MIN 0x1F8C
+#define SYSMON_TEMP_MAX_MAX 0x1F90
+#define SYSMON_TEMP_SAT_BASE 0x1FAC
+#define SYSMON_MAX_REG 0x24C0
+
+/* NPI unlock value written to SYSMON_NPI_LOCK */
+#define SYSMON_NPI_UNLOCK_CODE 0xF9E8D7C6
+
+/* Register stride: 4 bytes per 32-bit register */
+#define SYSMON_REG_STRIDE 4
+
+#define SYSMON_SUPPLY_IDX_MAX 159
+#define SYSMON_TEMP_SAT_MAX 64
+#define SYSMON_INTR_ALL_MASK GENMASK(31, 0)
+
+/* Supply voltage conversion register fields */
+#define SYSMON_MANTISSA_MASK GENMASK(15, 0)
+#define SYSMON_FMT_MASK BIT(16)
+#define SYSMON_MODE_MASK GENMASK(18, 17)
+
+/* Q8.7 fractional shift */
+#define SYSMON_FRACTIONAL_SHIFT 7U
+#define SYSMON_SUPPLY_MANTISSA_BITS 16
+
+/**
+ * struct sysmon - Driver data for Versal SysMon
+ * @regmap: register map for hardware access
+ * @lock: protects read-modify-write sequences on threshold registers
+ * and cached state that spans multiple regmap calls
+ */
+struct sysmon {
+ struct regmap *regmap;
+ /*
+ * Protects read-modify-write sequences on threshold registers
+ * and cached state (oversampling ratios, hysteresis values)
+ * that spans multiple regmap calls.
+ */
+ struct mutex lock;
+};
+
+int sysmon_core_probe(struct device *dev, struct regmap *regmap);
+
+#endif /* _VERSAL_SYSMON_H_ */
--
2.48.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v5 3/5] iio: adc: versal-sysmon: add I2C driver
2026-06-08 18:37 [PATCH v5 0/5] iio: adc: add AMD/Xilinx Versal SysMon driver Salih Erim
2026-06-08 18:37 ` [PATCH v5 1/5] dt-bindings: iio: adc: add xlnx,versal-sysmon binding Salih Erim
2026-06-08 18:37 ` [PATCH v5 2/5] iio: adc: add Versal SysMon driver Salih Erim
@ 2026-06-08 18:37 ` Salih Erim
2026-06-08 18:52 ` sashiko-bot
2026-06-08 18:38 ` [PATCH v5 4/5] iio: adc: versal-sysmon: add threshold event support Salih Erim
2026-06-08 18:38 ` [PATCH v5 5/5] iio: adc: versal-sysmon: add oversampling support Salih Erim
4 siblings, 1 reply; 9+ messages in thread
From: Salih Erim @ 2026-06-08 18:37 UTC (permalink / raw)
To: jic23, andy
Cc: dlechner, nuno.sa, robh, krzk+dt, conor+dt, conall.ogriofa,
michal.simek, linux, erimsalih, linux-iio, devicetree,
linux-kernel, Salih Erim
Add an I2C transport driver for the Versal SysMon block. The SysMon
provides an I2C slave interface that allows an external master to
read voltage and temperature measurements through the same register
map used by the MMIO path.
The I2C command frame is an 8-byte structure containing a 4-byte data
payload, a 2-byte register offset, and a 1-byte instruction field.
Read operations send the frame with a read instruction, then receive
a 4-byte response containing the register value.
Events are not supported on the I2C path because there is no
interrupt line and the I2C regmap backend cannot be called from
atomic context.
Co-developed-by: Conall O'Griofa <conall.ogriofa@amd.com>
Signed-off-by: Conall O'Griofa <conall.ogriofa@amd.com>
Signed-off-by: Salih Erim <salih.erim@amd.com>
---
Changes in v5:
- Add err.h, mod_devicetable.h includes (IWYU) (Andy)
Changes in v4:
- Replace enum with defines for I2C frame offsets (Jonathan)
- Use get_unaligned_le32() for read data reassembly (Jonathan)
- Use put_unaligned_le32/le16() for write data and register offset
packing (Jonathan)
- Named initializer in i2c_device_id (Jonathan)
- Drop bitfield.h, add unaligned.h (FIELD_GET/FIELD_PREP replaced
by unaligned accessors)
Changes in v3:
- IWYU: fix includes (Andy)
- Enum: assign all values explicitly for HW-mapped fields (Andy)
- Remove sysmon_i2c wrapper struct, pass i2c_client directly
(Andy)
- Use sizeof() for I2C buffer lengths instead of defines (Andy)
- Use = { } instead of = { 0 } for initializers (Andy)
- Use single compatible xlnx,versal-sysmon (Krzysztof)
- Adapt to core_probe interface change: irq moved to core,
remove irq parameter from bus driver (Jonathan)
Changes in v2:
- New patch (I2C was deferred to Series B in v1)
- Uses regmap API with custom I2C read/write callbacks
- Shares core module with MMIO driver via sysmon_core_probe()
- No event support (I2C has no interrupt line)
- Separate VERSAL_SYSMON_I2C Kconfig symbol
- Reverse Christmas Tree variable ordering in read/write functions
drivers/iio/adc/Kconfig | 13 +++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/versal-sysmon-i2c.c | 127 ++++++++++++++++++++++++++++
3 files changed, 141 insertions(+)
create mode 100644 drivers/iio/adc/versal-sysmon-i2c.c
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index c7f19057484..8f9fc9de74a 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1963,6 +1963,19 @@ config VERSAL_SYSMON
To compile this driver as a module, choose M here: the module
will be called versal-sysmon.
+config VERSAL_SYSMON_I2C
+ tristate "AMD Versal SysMon I2C driver"
+ depends on I2C
+ select VERSAL_SYSMON_CORE
+ help
+ Say yes here to have support for the AMD/Xilinx Versal System
+ Monitor (SysMon) via I2C interface. This driver enables voltage
+ and temperature monitoring when the Versal chip has SysMon
+ configured with I2C access.
+
+ To compile this driver as a module, choose M here: the module
+ will be called versal-sysmon-i2c.
+
config VF610_ADC
tristate "Freescale vf610 ADC driver"
depends on HAS_IOMEM
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index d7696b1b157..5abb611fe46 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -169,6 +169,7 @@ obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
obj-$(CONFIG_TWL6030_GPADC) += twl6030-gpadc.o
obj-$(CONFIG_VERSAL_SYSMON_CORE) += versal-sysmon-core.o
obj-$(CONFIG_VERSAL_SYSMON) += versal-sysmon.o
+obj-$(CONFIG_VERSAL_SYSMON_I2C) += versal-sysmon-i2c.o
obj-$(CONFIG_VF610_ADC) += vf610_adc.o
obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
obj-$(CONFIG_XILINX_AMS) += xilinx-ams.o
diff --git a/drivers/iio/adc/versal-sysmon-i2c.c b/drivers/iio/adc/versal-sysmon-i2c.c
new file mode 100644
index 00000000000..1d1e97e1931
--- /dev/null
+++ b/drivers/iio/adc/versal-sysmon-i2c.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD Versal SysMon I2C driver
+ *
+ * Copyright (C) 2023 - 2026, Advanced Micro Devices, Inc.
+ */
+
+#include <linux/bits.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/unaligned.h>
+
+#include "versal-sysmon.h"
+
+#define SYSMON_I2C_INSTR_READ BIT(2)
+#define SYSMON_I2C_INSTR_WRITE BIT(3)
+
+/*
+ * I2C command frame layout (8 bytes):
+ * [0..3] data payload (little-endian u32)
+ * [4..5] register offset >> 2 (little-endian u16)
+ * [6] instruction (read/write)
+ * [7] reserved
+ */
+#define SYSMON_I2C_DATA_OFS 0
+#define SYSMON_I2C_REG_OFS 4
+#define SYSMON_I2C_INSTR_OFS 6
+
+static int sysmon_i2c_reg_read(void *context, unsigned int reg,
+ unsigned int *val)
+{
+ struct i2c_client *client = context;
+ u8 write_buf[8] = { };
+ u8 read_buf[4];
+ int ret;
+
+ put_unaligned_le16(reg >> 2, &write_buf[SYSMON_I2C_REG_OFS]);
+ write_buf[SYSMON_I2C_INSTR_OFS] = SYSMON_I2C_INSTR_READ;
+
+ ret = i2c_master_send(client, write_buf, sizeof(write_buf));
+ if (ret < 0)
+ return ret;
+ if (ret != sizeof(write_buf))
+ return -EIO;
+
+ ret = i2c_master_recv(client, read_buf, sizeof(read_buf));
+ if (ret < 0)
+ return ret;
+ if (ret != sizeof(read_buf))
+ return -EIO;
+
+ *val = get_unaligned_le32(read_buf);
+
+ return 0;
+}
+
+static int sysmon_i2c_reg_write(void *context, unsigned int reg,
+ unsigned int val)
+{
+ struct i2c_client *client = context;
+ u8 write_buf[8] = { };
+ int ret;
+
+ put_unaligned_le32(val, &write_buf[SYSMON_I2C_DATA_OFS]);
+ put_unaligned_le16(reg >> 2, &write_buf[SYSMON_I2C_REG_OFS]);
+ write_buf[SYSMON_I2C_INSTR_OFS] = SYSMON_I2C_INSTR_WRITE;
+
+ ret = i2c_master_send(client, write_buf, sizeof(write_buf));
+ if (ret < 0)
+ return ret;
+ if (ret != sizeof(write_buf))
+ return -EIO;
+
+ return 0;
+}
+
+static const struct regmap_config sysmon_i2c_regmap_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = SYSMON_REG_STRIDE,
+ .max_register = SYSMON_MAX_REG,
+ .reg_read = sysmon_i2c_reg_read,
+ .reg_write = sysmon_i2c_reg_write,
+};
+
+static int sysmon_i2c_probe(struct i2c_client *client)
+{
+ struct regmap *regmap;
+
+ regmap = devm_regmap_init(&client->dev, NULL, client,
+ &sysmon_i2c_regmap_config);
+ if (IS_ERR(regmap))
+ return PTR_ERR(regmap);
+
+ /* I2C has no IRQ connection; events are not supported */
+ return sysmon_core_probe(&client->dev, regmap);
+}
+
+static const struct of_device_id sysmon_i2c_of_match_table[] = {
+ { .compatible = "xlnx,versal-sysmon" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, sysmon_i2c_of_match_table);
+
+static const struct i2c_device_id sysmon_i2c_id_table[] = {
+ { .name = "versal-sysmon" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, sysmon_i2c_id_table);
+
+static struct i2c_driver sysmon_i2c_driver = {
+ .probe = sysmon_i2c_probe,
+ .driver = {
+ .name = "versal-sysmon-i2c",
+ .of_match_table = sysmon_i2c_of_match_table,
+ },
+ .id_table = sysmon_i2c_id_table,
+};
+module_i2c_driver(sysmon_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("AMD Versal SysMon I2C Driver");
+MODULE_AUTHOR("Conall O'Griofa <conall.ogriofa@amd.com>");
+MODULE_AUTHOR("Salih Erim <salih.erim@amd.com>");
--
2.48.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH v5 3/5] iio: adc: versal-sysmon: add I2C driver
2026-06-08 18:37 ` [PATCH v5 3/5] iio: adc: versal-sysmon: add I2C driver Salih Erim
@ 2026-06-08 18:52 ` sashiko-bot
0 siblings, 0 replies; 9+ messages in thread
From: sashiko-bot @ 2026-06-08 18:52 UTC (permalink / raw)
To: Salih Erim; +Cc: conor+dt, devicetree, robh
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Unconditional probe failure for I2C devices due to incorrect handling of optional IRQ.
--
commit f3303ed1c4a2a87b882fc5ca294a42e9cb520b70
Author: Salih Erim <salih.erim@amd.com>
iio: adc: versal-sysmon: add I2C driver
This commit adds an I2C transport driver for the Versal SysMon block, allowing
an external master to read voltage and temperature measurements. It explicitly
omits event support as the I2C path does not have an interrupt line.
> diff --git a/drivers/iio/adc/versal-sysmon-i2c.c b/drivers/iio/adc/versal-sysmon-i2c.c
> new file mode 100644
> --- /dev/null
> +++ b/drivers/iio/adc/versal-sysmon-i2c.c
[ ... ]
> +static int sysmon_i2c_probe(struct i2c_client *client)
> +{
> + struct regmap *regmap;
> +
> + regmap = devm_regmap_init(&client->dev, NULL, client,
> + &sysmon_i2c_regmap_config);
> + if (IS_ERR(regmap))
> + return PTR_ERR(regmap);
> +
> + /* I2C has no IRQ connection; events are not supported */
> + return sysmon_core_probe(&client->dev, regmap);
[Severity: High]
Will this unconditionally fail to probe when called from the I2C driver?
Looking at sysmon_core_probe() in versal-sysmon-core.c, it attempts to
get an IRQ and treats any negative return as a fatal error:
int sysmon_core_probe(struct device *dev, struct regmap *regmap)
{
...
irq = fwnode_irq_get(dev_fwnode(dev), 0);
if (irq < 0)
return dev_err_probe(dev, irq, "failed to get IRQ\n");
Since the I2C device tree node lacks an interrupts property, fwnode_irq_get()
will return a negative error code (such as -EINVAL), which causes the probe
to fail entirely before it can successfully initialize the device.
Should the core probe gracefully handle missing optional IRQs so that the
I2C driver can succeed?
> +}
[ ... ]
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260608183801.1257051-1-salih.erim@amd.com?part=3
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v5 4/5] iio: adc: versal-sysmon: add threshold event support
2026-06-08 18:37 [PATCH v5 0/5] iio: adc: add AMD/Xilinx Versal SysMon driver Salih Erim
` (2 preceding siblings ...)
2026-06-08 18:37 ` [PATCH v5 3/5] iio: adc: versal-sysmon: add I2C driver Salih Erim
@ 2026-06-08 18:38 ` Salih Erim
2026-06-08 18:52 ` sashiko-bot
2026-06-08 18:38 ` [PATCH v5 5/5] iio: adc: versal-sysmon: add oversampling support Salih Erim
4 siblings, 1 reply; 9+ messages in thread
From: Salih Erim @ 2026-06-08 18:38 UTC (permalink / raw)
To: jic23, andy
Cc: dlechner, nuno.sa, robh, krzk+dt, conor+dt, conall.ogriofa,
michal.simek, linux, erimsalih, linux-iio, devicetree,
linux-kernel, Salih Erim
Add threshold event support for temperature and supply voltage
channels.
Temperature events:
- Rising threshold with configurable value
- Over-temperature (OT) alarm with separate threshold
- Per-channel hysteresis as a millicelsius value
- Event direction is IIO_EV_DIR_RISING (hysteresis mode)
Supply voltage events:
- Rising/falling threshold per supply channel
- Per-channel alarm enable via alarm configuration registers
The hardware supports both window and hysteresis alarm modes for
temperature. This driver uses hysteresis mode, where the upper
threshold triggers the alarm and the lower threshold clears it
(re-arm point). The hardware has a single ISR bit per temperature
channel with no indication of which threshold was crossed, so
hysteresis mode is the natural fit. The lower threshold register
is computed internally as (upper - hysteresis).
Hysteresis is stored in the driver as a millicelsius value,
initialized from the hardware registers at probe. Writing the
rising threshold or hysteresis recomputes the lower register.
ALARM_CONFIG is hard-coded to hysteresis mode during init.
The interrupt handler masks active threshold interrupts (which are
level-sensitive) and schedules a delayed worker to poll for condition
clear before unmasking. When no hardware IRQ is available, event
channels are not created and interrupt init is skipped, since the
I2C regmap backend cannot be called from atomic context.
When disabling a supply channel alarm, the group interrupt remains
active if any other channel in the same alarm group still has an
alarm enabled.
Signed-off-by: Salih Erim <salih.erim@amd.com>
---
Changes in v5:
- clamp() instead of clamp_t() (Andy)
- regmap_assign_bits() instead of separate set/clear (Andy)
- Remove unneeded parentheses (2 places) (Andy)
- for_each_set_bit on single line (Andy)
- regmap_clear_bits() instead of regmap_update_bits() (Andy)
- Simplify unmask XOR to ~status & masked_temp (Andy)
- Add comment explaining unmask &= ~temp_mask logic (Andy)
- Split container_of across two lines (Andy)
- Move ISR write after !isr check to avoid writing 0 (Andy)
- unsigned int for init_hysteresis address param (Andy)
- Add comment explaining error check policy in worker/IRQ (Andy)
- Nested size_add() for overflow-safe allocation (Andy)
- Propagate negative from fwnode_irq_get() for
EPROBE_DEFER (Andy)
- Pass irq instead of has_irq to sysmon_parse_fw (Andy)
Changes in v4:
- Merge event channels into static temp array; two arrays
(with/without events) selected by has_irq (Jonathan)
- Event-only channels have no info_mask; their addresses are
logical identifiers, not readable registers
- Drop RAW for voltage events, keep PROCESSED only (Jonathan)
- Drop scan_type from event channel macro (Jonathan)
- Blank lines between call+error-check blocks (Jonathan)
- Fit under 80 chars on one line where possible (Jonathan)
- default case returns -EINVAL instead of break (Jonathan)
- sysmon_handle_event: return early in each case (Jonathan)
- guard(spinlock) in sysmon_iio_irq, return IRQ_NONE/IRQ_HANDLED
directly (Jonathan)
- Take irq_lock in write_event_config for temp_mask updates to
synchronize with unmask worker (Sashiko)
Changes in v3:
- IWYU: add new includes, group iio headers with blank line (Andy)
- Reduce casts in millicelsius_to_q8p7, consistent style with
q8p7_to_millicelsius (Andy)
- Use clamp_t with typed constants, remove tmp & U16_MAX (Andy)
- Use !! to return 0/1 from read_alarm_config (Andy)
- Use regmap_set_bits/clear_bits in write_alarm_config (Andy)
- Add comment explaining spinlock is safe (I2C never reaches
event code path) (Andy)
- Add comment explaining IMR negation logic (Andy)
- Split read_event_value/write_event_value parameters logically
across lines (Andy)
- Move mask/shift after regmap_read error check (Andy)
- Remove redundant else in read_event_value and
write_event_value (Andy)
- Use named constant for hysteresis bit, if-else not ternary
(Andy)
- Loop variable declared in for() scope (Andy)
- Add error checks in sysmon_handle_event (Andy)
- Use IRQ_RETVAL() macro (Andy)
- Use devm_delayed_work_autocancel instead of manual INIT +
devm_add_action (Andy)
- Use FIELD_GET/FIELD_PREP for hysteresis register bits
(Jonathan)
- Split OT vs TEMP handling with FIELD_GET (Jonathan)
- Rework hysteresis: store as millicelsius value, hardcode
ALARM_CONFIG to hysteresis mode, compute lower threshold
from (upper - hysteresis), initialize from HW at probe
(Jonathan)
- Remove falling threshold for temperature; single event
spec per channel with IIO_EV_DIR_RISING (Jonathan)
- Push IIO_EV_DIR_RISING events for temperature,
IIO_EV_DIR_EITHER for voltage (Jonathan)
Changes in v2:
- Reverse Christmas Tree variable ordering in all functions
- Named constants for hysteresis bits: SYSMON_OT_HYST_BIT,
SYSMON_TEMP_HYST_BIT instead of magic 0x1/0x2
- SYSMON_ALARM_BITS_PER_REG replaces magic number 32
- SYSMON_ALARM_OFFSET() helper macro deduplicates alarm register
offset computation
- BIT() macro for shift expressions in conversion functions
- Hysteresis input validated to single-bit range (0 or 1)
- Event channels only created when irq > 0 (I2C safety)
- Group alarm interrupt stays active while any channel in the
group has an alarm enabled
- write_event_value returns -EINVAL for unhandled types
- IRQ_NONE returned for spurious interrupts
- Q8.7 write path uses multiplication instead of left-shift
to avoid undefined behavior with negative temperatures
- (u16) mask prevents garbage in reserved register bits
- regmap_write return values checked for IER/IDR writes
- devm cleanup ordering: cancel_work before request_irq
drivers/iio/adc/versal-sysmon-core.c | 680 ++++++++++++++++++++++++++-
drivers/iio/adc/versal-sysmon.h | 45 ++
2 files changed, 716 insertions(+), 9 deletions(-)
diff --git a/drivers/iio/adc/versal-sysmon-core.c b/drivers/iio/adc/versal-sysmon-core.c
index c7b5eecc93c..5fbd509089b 100644
--- a/drivers/iio/adc/versal-sysmon-core.c
+++ b/drivers/iio/adc/versal-sysmon-core.c
@@ -11,7 +11,9 @@
#include <linux/bitops.h>
#include <linux/cleanup.h>
#include <linux/device.h>
+#include <linux/devm-helpers.h>
#include <linux/err.h>
+#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regmap.h>
@@ -19,10 +21,19 @@
#include <linux/sysfs.h>
#include <linux/units.h>
+#include <linux/iio/events.h>
#include <linux/iio/iio.h>
#include "versal-sysmon.h"
+/* OT and TEMP hysteresis mode bits in SYSMON_TEMP_EV_CFG */
+#define SYSMON_OT_HYST_MASK BIT(0)
+#define SYSMON_TEMP_HYST_MASK BIT(1)
+
+/* Compute alarm register offset from a channel address */
+#define SYSMON_ALARM_OFFSET(addr) \
+ (SYSMON_ALARM_REG + ((addr) / SYSMON_ALARM_BITS_PER_REG) * SYSMON_REG_STRIDE)
+
#define SYSMON_CHAN_TEMP(_chan, _address, _name) { \
.type = IIO_TEMP, \
.indexed = 1, \
@@ -33,14 +44,86 @@
.datasheet_name = _name, \
}
+#define SYSMON_CHAN_TEMP_EVENT(_chan, _address, _name, _events) {\
+ .type = IIO_TEMP, \
+ .indexed = 1, \
+ .address = _address, \
+ .channel = _chan, \
+ .event_spec = _events, \
+ .num_event_specs = ARRAY_SIZE(_events), \
+ .datasheet_name = _name, \
+}
+
+enum sysmon_alarm_bit {
+ SYSMON_BIT_ALARM0 = 0,
+ SYSMON_BIT_ALARM1 = 1,
+ SYSMON_BIT_ALARM2 = 2,
+ SYSMON_BIT_ALARM3 = 3,
+ SYSMON_BIT_ALARM4 = 4,
+ SYSMON_BIT_OT = 8,
+ SYSMON_BIT_TEMP = 9,
+};
+
+/* Temperature event specification: rising threshold + hysteresis only */
+static const struct iio_event_spec sysmon_temp_events[] = {
+ {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_RISING,
+ .mask_separate = BIT(IIO_EV_INFO_ENABLE) |
+ BIT(IIO_EV_INFO_VALUE) |
+ BIT(IIO_EV_INFO_HYSTERESIS),
+ },
+};
+
+/* Supply event specifications */
+static const struct iio_event_spec sysmon_supply_events[] = {
+ {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_RISING,
+ .mask_separate = BIT(IIO_EV_INFO_VALUE),
+ },
+ {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_FALLING,
+ .mask_separate = BIT(IIO_EV_INFO_VALUE),
+ },
+ {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_EITHER,
+ .mask_separate = BIT(IIO_EV_INFO_ENABLE),
+ },
+};
+
/* Static temperature channels (always present) */
-static const struct iio_chan_spec temp_channels[] = {
+static const struct iio_chan_spec temp_channels_no_events[] = {
+ SYSMON_CHAN_TEMP(0, SYSMON_TEMP_MAX, "temp"),
+ SYSMON_CHAN_TEMP(1, SYSMON_TEMP_MIN, "min"),
+ SYSMON_CHAN_TEMP(2, SYSMON_TEMP_MAX_MAX, "max_max"),
+ SYSMON_CHAN_TEMP(3, SYSMON_TEMP_MIN_MIN, "min_min"),
+};
+
+/* Static temperature channels with event support (when IRQ available) */
+static const struct iio_chan_spec temp_channels_with_events[] = {
SYSMON_CHAN_TEMP(0, SYSMON_TEMP_MAX, "temp"),
SYSMON_CHAN_TEMP(1, SYSMON_TEMP_MIN, "min"),
SYSMON_CHAN_TEMP(2, SYSMON_TEMP_MAX_MAX, "max_max"),
SYSMON_CHAN_TEMP(3, SYSMON_TEMP_MIN_MIN, "min_min"),
+ SYSMON_CHAN_TEMP_EVENT(4, SYSMON_ADDR_TEMP_EVENT, "temp",
+ sysmon_temp_events),
+ SYSMON_CHAN_TEMP_EVENT(5, SYSMON_ADDR_OT_EVENT, "ot",
+ sysmon_temp_events),
};
+static void sysmon_q8p7_to_millicelsius(s16 raw_data, int *val)
+{
+ *val = (raw_data * (int)MILLI) >> SYSMON_FRACTIONAL_SHIFT;
+}
+
+static void sysmon_millicelsius_to_q8p7(u32 *raw_data, int val)
+{
+ *raw_data = (val << SYSMON_FRACTIONAL_SHIFT) / (int)MILLI;
+}
+
static void sysmon_supply_rawtoprocessed(int raw_data, int *val)
{
int mantissa, format, exponent;
@@ -58,6 +141,49 @@ static void sysmon_supply_rawtoprocessed(int raw_data, int *val)
*val = (mantissa * (int)MILLI) >> exponent;
}
+static void sysmon_supply_processedtoraw(int val, u32 reg_val, u32 *raw_data)
+{
+ int exponent = FIELD_GET(SYSMON_MODE_MASK, reg_val);
+ int format = FIELD_GET(SYSMON_FMT_MASK, reg_val);
+ int scale, tmp;
+
+ scale = BIT(SYSMON_SUPPLY_MANTISSA_BITS - exponent);
+ tmp = (val * scale) / (int)MILLI;
+
+ if (format)
+ tmp = clamp(tmp, S16_MIN, S16_MAX);
+ else
+ tmp = clamp(tmp, 0, U16_MAX);
+
+ *raw_data = (u16)tmp;
+}
+
+static int sysmon_temp_thresh_offset(int address,
+ enum iio_event_direction dir)
+{
+ switch (address) {
+ case SYSMON_ADDR_TEMP_EVENT:
+ return (dir == IIO_EV_DIR_RISING) ? SYSMON_TEMP_TH_UP :
+ SYSMON_TEMP_TH_LOW;
+ case SYSMON_ADDR_OT_EVENT:
+ return (dir == IIO_EV_DIR_RISING) ? SYSMON_OT_TH_UP :
+ SYSMON_OT_TH_LOW;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int sysmon_supply_thresh_offset(int address,
+ enum iio_event_direction dir)
+{
+ if (dir == IIO_EV_DIR_RISING)
+ return (address * SYSMON_REG_STRIDE) + SYSMON_SUPPLY_TH_UP;
+ if (dir == IIO_EV_DIR_FALLING)
+ return (address * SYSMON_REG_STRIDE) + SYSMON_SUPPLY_TH_LOW;
+
+ return -EINVAL;
+}
+
static int sysmon_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
@@ -104,6 +230,272 @@ static int sysmon_read_raw(struct iio_dev *indio_dev,
}
}
+static int sysmon_get_event_mask(unsigned long address)
+{
+ if (address == SYSMON_ADDR_TEMP_EVENT)
+ return BIT(SYSMON_BIT_TEMP);
+ if (address == SYSMON_ADDR_OT_EVENT)
+ return BIT(SYSMON_BIT_OT);
+
+ return BIT(address / SYSMON_ALARM_BITS_PER_REG);
+}
+
+static int sysmon_read_alarm_config(struct sysmon *sysmon,
+ unsigned long address)
+{
+ u32 shift = address % SYSMON_ALARM_BITS_PER_REG;
+ u32 offset = SYSMON_ALARM_OFFSET(address);
+ unsigned int reg_val;
+ int ret;
+
+ ret = regmap_read(sysmon->regmap, offset, ®_val);
+ if (ret)
+ return ret;
+
+ return !!(reg_val & BIT(shift));
+}
+
+static int sysmon_write_alarm_config(struct sysmon *sysmon,
+ unsigned long address, bool enable)
+{
+ u32 shift = address % SYSMON_ALARM_BITS_PER_REG;
+ u32 offset = SYSMON_ALARM_OFFSET(address);
+
+ return regmap_assign_bits(sysmon->regmap, offset, BIT(shift), enable);
+}
+
+static int sysmon_read_event_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir)
+{
+ u32 alarm_event_mask = sysmon_get_event_mask(chan->address);
+ struct sysmon *sysmon = iio_priv(indio_dev);
+ unsigned int imr;
+ int config_value;
+ int ret;
+
+ ret = regmap_read(sysmon->regmap, SYSMON_IMR, &imr);
+ if (ret)
+ return ret;
+
+ /* IMR bits are 1=masked, invert to get 1=enabled */
+ imr = ~imr;
+
+ if (chan->type == IIO_VOLTAGE) {
+ config_value = sysmon_read_alarm_config(sysmon, chan->address);
+ if (config_value < 0)
+ return config_value;
+ return config_value && (imr & alarm_event_mask);
+ }
+
+ return !!(imr & alarm_event_mask);
+}
+
+static int sysmon_write_event_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ bool state)
+{
+ u32 offset = SYSMON_ALARM_OFFSET(chan->address);
+ u32 ier = sysmon_get_event_mask(chan->address);
+ struct sysmon *sysmon = iio_priv(indio_dev);
+ unsigned int alarm_config;
+ int ret;
+
+ guard(mutex)(&sysmon->lock);
+
+ if (chan->type == IIO_VOLTAGE) {
+ ret = sysmon_write_alarm_config(sysmon, chan->address, state);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(sysmon->regmap, offset, &alarm_config);
+ if (ret)
+ return ret;
+
+ if (alarm_config)
+ return regmap_write(sysmon->regmap, SYSMON_IER, ier);
+
+ return regmap_write(sysmon->regmap, SYSMON_IDR, ier);
+ }
+
+ if (chan->type == IIO_TEMP) {
+ if (state) {
+ ret = regmap_write(sysmon->regmap, SYSMON_IER, ier);
+ if (ret)
+ return ret;
+
+ scoped_guard(spinlock_irq, &sysmon->irq_lock)
+ sysmon->temp_mask &= ~ier;
+ } else {
+ ret = regmap_write(sysmon->regmap, SYSMON_IDR, ier);
+ if (ret)
+ return ret;
+
+ scoped_guard(spinlock_irq, &sysmon->irq_lock)
+ sysmon->temp_mask |= ier;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Recompute the lower threshold register from upper threshold and
+ * cached hysteresis. Called when either upper threshold or hysteresis
+ * is written.
+ */
+static int sysmon_update_temp_lower(struct sysmon *sysmon, int address)
+{
+ unsigned int upper_reg;
+ int upper_mc, lower_mc, hysteresis;
+ u32 raw_val;
+ int upper_off, lower_off, ret;
+
+ upper_off = sysmon_temp_thresh_offset(address, IIO_EV_DIR_RISING);
+ if (upper_off < 0)
+ return upper_off;
+ lower_off = sysmon_temp_thresh_offset(address, IIO_EV_DIR_FALLING);
+ if (lower_off < 0)
+ return lower_off;
+
+ if (address == SYSMON_ADDR_OT_EVENT)
+ hysteresis = sysmon->ot_hysteresis;
+ else
+ hysteresis = sysmon->temp_hysteresis;
+
+ ret = regmap_read(sysmon->regmap, upper_off, &upper_reg);
+ if (ret)
+ return ret;
+
+ sysmon_q8p7_to_millicelsius(upper_reg, &upper_mc);
+
+ lower_mc = upper_mc - hysteresis;
+ sysmon_millicelsius_to_q8p7(&raw_val, lower_mc);
+
+ return regmap_write(sysmon->regmap, lower_off, raw_val);
+}
+
+static int sysmon_read_event_value(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info,
+ int *val, int *val2)
+{
+ struct sysmon *sysmon = iio_priv(indio_dev);
+ unsigned int reg_val;
+ int offset;
+ int ret;
+
+ guard(mutex)(&sysmon->lock);
+
+ if (chan->type == IIO_TEMP) {
+ if (info == IIO_EV_INFO_VALUE) {
+ /* Only rising threshold is exposed */
+ offset = sysmon_temp_thresh_offset(chan->address,
+ IIO_EV_DIR_RISING);
+ if (offset < 0)
+ return offset;
+
+ ret = regmap_read(sysmon->regmap, offset, ®_val);
+ if (ret)
+ return ret;
+
+ sysmon_q8p7_to_millicelsius(reg_val, val);
+
+ return IIO_VAL_INT;
+ }
+ if (info == IIO_EV_INFO_HYSTERESIS) {
+ if (chan->address == SYSMON_ADDR_OT_EVENT)
+ *val = sysmon->ot_hysteresis;
+ else
+ *val = sysmon->temp_hysteresis;
+ return IIO_VAL_INT;
+ }
+ }
+
+ if (chan->type == IIO_VOLTAGE) {
+ offset = sysmon_supply_thresh_offset(chan->address, dir);
+ if (offset < 0)
+ return offset;
+
+ ret = regmap_read(sysmon->regmap, offset, ®_val);
+ if (ret)
+ return ret;
+
+ sysmon_supply_rawtoprocessed(reg_val, val);
+
+ return IIO_VAL_INT;
+ }
+
+ return -EINVAL;
+}
+
+static int sysmon_write_event_value(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info,
+ int val, int val2)
+{
+ struct sysmon *sysmon = iio_priv(indio_dev);
+ unsigned int reg_val;
+ u32 raw_val;
+ int offset;
+ int ret;
+
+ guard(mutex)(&sysmon->lock);
+
+ if (chan->type == IIO_TEMP) {
+ if (info == IIO_EV_INFO_VALUE) {
+ /* Only rising threshold is exposed */
+ offset = sysmon_temp_thresh_offset(chan->address,
+ IIO_EV_DIR_RISING);
+ if (offset < 0)
+ return offset;
+
+ sysmon_millicelsius_to_q8p7(&raw_val, val);
+
+ ret = regmap_write(sysmon->regmap, offset, raw_val);
+ if (ret)
+ return ret;
+
+ /* Recompute lower = upper - hysteresis */
+ return sysmon_update_temp_lower(sysmon, chan->address);
+ }
+ if (info == IIO_EV_INFO_HYSTERESIS) {
+ if (val < 0)
+ return -EINVAL;
+
+ if (chan->address == SYSMON_ADDR_OT_EVENT)
+ sysmon->ot_hysteresis = val;
+ else
+ sysmon->temp_hysteresis = val;
+
+ return sysmon_update_temp_lower(sysmon, chan->address);
+ }
+ }
+
+ if (chan->type == IIO_VOLTAGE) {
+ offset = sysmon_supply_thresh_offset(chan->address, dir);
+ if (offset < 0)
+ return offset;
+
+ ret = regmap_read(sysmon->regmap, offset, ®_val);
+ if (ret)
+ return ret;
+
+ sysmon_supply_processedtoraw(val, reg_val, &raw_val);
+
+ return regmap_write(sysmon->regmap, offset, raw_val);
+ }
+
+ return -EINVAL;
+}
+
static int sysmon_read_label(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
char *label)
@@ -117,23 +509,252 @@ static int sysmon_read_label(struct iio_dev *indio_dev,
static const struct iio_info sysmon_iio_info = {
.read_raw = sysmon_read_raw,
.read_label = sysmon_read_label,
+ .read_event_config = sysmon_read_event_config,
+ .write_event_config = sysmon_write_event_config,
+ .read_event_value = sysmon_read_event_value,
+ .write_event_value = sysmon_write_event_value,
};
+static void sysmon_push_event(struct iio_dev *indio_dev, u32 address)
+{
+ const struct iio_chan_spec *chan;
+ enum iio_event_direction dir;
+
+ for (unsigned int i = 0; i < indio_dev->num_channels; i++) {
+ if (indio_dev->channels[i].address != address)
+ continue;
+
+ chan = &indio_dev->channels[i];
+ /* Temp uses hysteresis mode (rising only), voltage uses window */
+ dir = (chan->type == IIO_TEMP) ? IIO_EV_DIR_RISING :
+ IIO_EV_DIR_EITHER;
+ iio_push_event(indio_dev,
+ IIO_UNMOD_EVENT_CODE(chan->type,
+ chan->channel,
+ IIO_EV_TYPE_THRESH,
+ dir),
+ iio_get_time_ns(indio_dev));
+ }
+}
+
+static int sysmon_handle_event(struct iio_dev *indio_dev, u32 event)
+{
+ u32 alarm_flag_offset = SYSMON_ALARM_FLAG + event * SYSMON_REG_STRIDE;
+ u32 alarm_reg_offset = SYSMON_ALARM_REG + event * SYSMON_REG_STRIDE;
+ struct sysmon *sysmon = iio_priv(indio_dev);
+ unsigned long alarm_flag_reg;
+ unsigned int reg_val;
+ u32 address, bit;
+ int ret;
+
+ switch (event) {
+ case SYSMON_BIT_TEMP:
+ sysmon_push_event(indio_dev, SYSMON_ADDR_TEMP_EVENT);
+
+ ret = regmap_write(sysmon->regmap, SYSMON_IDR, BIT(SYSMON_BIT_TEMP));
+ if (ret)
+ return ret;
+
+ sysmon->masked_temp |= BIT(SYSMON_BIT_TEMP);
+ return 0;
+
+ case SYSMON_BIT_OT:
+ sysmon_push_event(indio_dev, SYSMON_ADDR_OT_EVENT);
+
+ ret = regmap_write(sysmon->regmap, SYSMON_IDR, BIT(SYSMON_BIT_OT));
+ if (ret)
+ return ret;
+
+ sysmon->masked_temp |= BIT(SYSMON_BIT_OT);
+ return 0;
+
+ case SYSMON_BIT_ALARM0:
+ case SYSMON_BIT_ALARM1:
+ case SYSMON_BIT_ALARM2:
+ case SYSMON_BIT_ALARM3:
+ case SYSMON_BIT_ALARM4:
+ ret = regmap_read(sysmon->regmap, alarm_flag_offset, ®_val);
+ if (ret)
+ return ret;
+
+ alarm_flag_reg = reg_val;
+
+ for_each_set_bit(bit, &alarm_flag_reg, SYSMON_ALARM_BITS_PER_REG) {
+ address = bit + SYSMON_ALARM_BITS_PER_REG * event;
+ sysmon_push_event(indio_dev, address);
+ ret = regmap_clear_bits(sysmon->regmap, alarm_reg_offset, BIT(bit));
+ if (ret)
+ return ret;
+ }
+
+ return regmap_write(sysmon->regmap, alarm_flag_offset, alarm_flag_reg);
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static void sysmon_handle_events(struct iio_dev *indio_dev,
+ unsigned long events)
+{
+ unsigned int bit;
+
+ for_each_set_bit(bit, &events, SYSMON_NO_OF_EVENTS)
+ sysmon_handle_event(indio_dev, bit);
+}
+
+static void sysmon_unmask_temp(struct sysmon *sysmon, unsigned int isr)
+{
+ unsigned int unmask, status;
+
+ status = isr & SYSMON_TEMP_INTR_MASK;
+
+ unmask = ~status & sysmon->masked_temp;
+ sysmon->masked_temp &= status;
+
+ /* Only unmask if not administratively disabled by userspace */
+ unmask &= ~sysmon->temp_mask;
+
+ regmap_write(sysmon->regmap, SYSMON_IER, unmask);
+}
+
+/*
+ * Versal threshold interrupts are level-sensitive. Active threshold
+ * interrupts are masked in the handler and polled via delayed work
+ * until the condition clears, then unmasked.
+ */
+static void sysmon_unmask_worker(struct work_struct *work)
+{
+ struct sysmon *sysmon =
+ container_of(work, struct sysmon, sysmon_unmask_work.work);
+ unsigned int isr;
+
+ /*
+ * regmap errors are not checked here because the worker and IRQ
+ * handler cannot propagate errors. The MMIO regmap uses fast_io
+ * with direct readl/writel which cannot fail.
+ */
+ spin_lock_irq(&sysmon->irq_lock);
+ regmap_read(sysmon->regmap, SYSMON_ISR, &isr);
+ regmap_write(sysmon->regmap, SYSMON_ISR, isr);
+ sysmon_unmask_temp(sysmon, isr);
+ spin_unlock_irq(&sysmon->irq_lock);
+
+ if (sysmon->masked_temp)
+ schedule_delayed_work(&sysmon->sysmon_unmask_work,
+ msecs_to_jiffies(SYSMON_UNMASK_WORK_DELAY_MS));
+ else
+ regmap_write(sysmon->regmap, SYSMON_STATUS_RESET, 1);
+}
+
+static irqreturn_t sysmon_iio_irq(int irq, void *data)
+{
+ struct iio_dev *indio_dev = data;
+ struct sysmon *sysmon = iio_priv(indio_dev);
+ unsigned int isr, imr;
+
+ guard(spinlock)(&sysmon->irq_lock);
+
+ regmap_read(sysmon->regmap, SYSMON_ISR, &isr);
+ regmap_read(sysmon->regmap, SYSMON_IMR, &imr);
+
+ isr &= ~imr;
+ if (!isr)
+ return IRQ_NONE;
+
+ regmap_write(sysmon->regmap, SYSMON_ISR, isr);
+
+ sysmon_handle_events(indio_dev, isr);
+ schedule_delayed_work(&sysmon->sysmon_unmask_work,
+ msecs_to_jiffies(SYSMON_UNMASK_WORK_DELAY_MS));
+
+ return IRQ_HANDLED;
+}
+
+static int sysmon_init_interrupt(struct sysmon *sysmon,
+ struct device *dev,
+ struct iio_dev *indio_dev,
+ int irq)
+{
+ unsigned int imr;
+ int ret;
+
+ /* Events not supported without IRQ (e.g. I2C path) */
+ if (!irq)
+ return 0;
+
+ ret = devm_delayed_work_autocancel(dev, &sysmon->sysmon_unmask_work,
+ sysmon_unmask_worker);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(sysmon->regmap, SYSMON_IMR, &imr);
+ if (ret)
+ return ret;
+ sysmon->temp_mask = imr & SYSMON_TEMP_INTR_MASK;
+
+ return devm_request_irq(dev, irq, sysmon_iio_irq, 0,
+ "sysmon-irq", indio_dev);
+}
+
+/*
+ * Initialize the cached hysteresis for a temperature channel from the
+ * current hardware threshold registers: hysteresis = upper - lower.
+ */
+static int sysmon_init_hysteresis(struct sysmon *sysmon, unsigned int address,
+ int *hysteresis)
+{
+ unsigned int upper_reg, lower_reg;
+ int upper_mc, lower_mc;
+ int upper_off, lower_off;
+ int ret;
+
+ upper_off = sysmon_temp_thresh_offset(address, IIO_EV_DIR_RISING);
+ if (upper_off < 0)
+ return upper_off;
+ lower_off = sysmon_temp_thresh_offset(address, IIO_EV_DIR_FALLING);
+ if (lower_off < 0)
+ return lower_off;
+
+ ret = regmap_read(sysmon->regmap, upper_off, &upper_reg);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(sysmon->regmap, lower_off, &lower_reg);
+ if (ret)
+ return ret;
+
+ sysmon_q8p7_to_millicelsius(upper_reg, &upper_mc);
+ sysmon_q8p7_to_millicelsius(lower_reg, &lower_mc);
+ *hysteresis = upper_mc - lower_mc;
+
+ return 0;
+}
+
/**
* sysmon_parse_fw() - Parse firmware nodes and configure IIO channels.
* @indio_dev: IIO device instance
* @dev: Parent device
+ * @irq: IRQ number (positive enables event channels, 0 disables)
*
* Reads voltage-channels and temperature-channels container nodes from
* firmware and builds the IIO channel array. Static temperature channels
- * are prepended, followed by supply and satellite channels from DT.
+ * and event channels are prepended, followed by supply and satellite
+ * channels from DT.
+ *
+ * Event channels and per-channel event specs are only added when the
+ * device has an IRQ. I2C devices have no interrupt line, and the I2C
+ * regmap cannot be called from atomic context, so events are not
+ * supported on that path.
*
* Return: 0 on success, negative errno on failure.
*/
-static int sysmon_parse_fw(struct iio_dev *indio_dev, struct device *dev)
+static int sysmon_parse_fw(struct iio_dev *indio_dev, struct device *dev,
+ int irq)
{
+ const struct iio_chan_spec *temp_chans;
unsigned int num_supply = 0, num_temp = 0;
- unsigned int idx, temp_chan_idx, volt_chan_idx;
+ unsigned int num_static, idx, temp_chan_idx, volt_chan_idx;
struct iio_chan_spec *sysmon_channels;
const char *label;
u32 reg;
@@ -147,17 +768,25 @@ static int sysmon_parse_fw(struct iio_dev *indio_dev, struct device *dev)
device_get_named_child_node(dev, "temperature-channels");
num_temp = fwnode_get_child_node_count(temp_node);
+ if (irq > 0) {
+ temp_chans = temp_channels_with_events;
+ num_static = ARRAY_SIZE(temp_channels_with_events);
+ } else {
+ temp_chans = temp_channels_no_events;
+ num_static = ARRAY_SIZE(temp_channels_no_events);
+ }
+
sysmon_channels = devm_kcalloc(dev,
- size_add(size_add(ARRAY_SIZE(temp_channels),
+ size_add(size_add(num_static,
num_supply), num_temp),
sizeof(*sysmon_channels), GFP_KERNEL);
if (!sysmon_channels)
return -ENOMEM;
- /* Static temperature channels first (fixed indices) */
+ /* Static temperature channels (with or without events) */
idx = 0;
- memcpy(sysmon_channels, temp_channels, sizeof(temp_channels));
- idx += ARRAY_SIZE(temp_channels);
+ memcpy(sysmon_channels, temp_chans, num_static * sizeof(*temp_chans));
+ idx += num_static;
/* Supply channels from DT */
fwnode_for_each_child_node_scoped(supply_node, child) {
@@ -182,6 +811,10 @@ static int sysmon_parse_fw(struct iio_dev *indio_dev, struct device *dev)
.address = reg,
.info_mask_separate =
BIT(IIO_CHAN_INFO_PROCESSED),
+ .event_spec = irq > 0 ?
+ sysmon_supply_events : NULL,
+ .num_event_specs = irq > 0 ?
+ ARRAY_SIZE(sysmon_supply_events) : 0,
.datasheet_name = label,
};
}
@@ -248,6 +881,7 @@ int sysmon_core_probe(struct device *dev, struct regmap *regmap)
{
struct iio_dev *indio_dev;
struct sysmon *sysmon;
+ int irq;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*sysmon));
@@ -260,6 +894,7 @@ int sysmon_core_probe(struct device *dev, struct regmap *regmap)
ret = devm_mutex_init(dev, &sysmon->lock);
if (ret)
return ret;
+ spin_lock_init(&sysmon->irq_lock);
/* Disable all interrupts and clear pending status */
ret = regmap_write(sysmon->regmap, SYSMON_IDR, SYSMON_INTR_ALL_MASK);
@@ -269,13 +904,40 @@ int sysmon_core_probe(struct device *dev, struct regmap *regmap)
if (ret)
return ret;
+ irq = fwnode_irq_get(dev_fwnode(dev), 0);
+ if (irq < 0)
+ return dev_err_probe(dev, irq, "failed to get IRQ\n");
+
indio_dev->name = "versal-sysmon";
indio_dev->modes = INDIO_DIRECT_MODE;
- ret = sysmon_parse_fw(indio_dev, dev);
+ ret = sysmon_parse_fw(indio_dev, dev, irq);
if (ret)
return ret;
+ if (irq > 0) {
+ /* Set hysteresis mode for both temperature channels */
+ ret = regmap_set_bits(sysmon->regmap, SYSMON_TEMP_EV_CFG,
+ SYSMON_OT_HYST_MASK |
+ SYSMON_TEMP_HYST_MASK);
+ if (ret)
+ return ret;
+
+ /* Initialize cached hysteresis from hardware registers */
+ ret = sysmon_init_hysteresis(sysmon, SYSMON_ADDR_TEMP_EVENT,
+ &sysmon->temp_hysteresis);
+ if (ret)
+ return ret;
+ ret = sysmon_init_hysteresis(sysmon, SYSMON_ADDR_OT_EVENT,
+ &sysmon->ot_hysteresis);
+ if (ret)
+ return ret;
+
+ ret = sysmon_init_interrupt(sysmon, dev, indio_dev, irq);
+ if (ret)
+ return ret;
+ }
+
return devm_iio_device_register(dev, indio_dev);
}
EXPORT_SYMBOL_GPL(sysmon_core_probe);
diff --git a/drivers/iio/adc/versal-sysmon.h b/drivers/iio/adc/versal-sysmon.h
index 0c0c89f6e0c..b5861f7e882 100644
--- a/drivers/iio/adc/versal-sysmon.h
+++ b/drivers/iio/adc/versal-sysmon.h
@@ -11,6 +11,9 @@
#include <linux/bits.h>
#include <linux/mutex.h>
+#include <linux/spinlock_types.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
struct device;
struct regmap;
@@ -18,12 +21,24 @@ struct regmap;
/* Register offsets (sorted by address) */
#define SYSMON_NPI_LOCK 0x000C
#define SYSMON_ISR 0x0044
+#define SYSMON_IMR 0x0048
+#define SYSMON_IER 0x004C
#define SYSMON_IDR 0x0050
#define SYSMON_TEMP_MAX 0x1030
#define SYSMON_TEMP_MIN 0x1034
#define SYSMON_SUPPLY_BASE 0x1040
+#define SYSMON_ALARM_FLAG 0x1018
+#define SYSMON_ALARM_REG 0x1940
+#define SYSMON_TEMP_TH_LOW 0x1970
+#define SYSMON_TEMP_TH_UP 0x1974
+#define SYSMON_OT_TH_LOW 0x1978
+#define SYSMON_OT_TH_UP 0x197C
+#define SYSMON_SUPPLY_TH_LOW 0x1980
+#define SYSMON_SUPPLY_TH_UP 0x1C80
+#define SYSMON_TEMP_EV_CFG 0x1F84
#define SYSMON_TEMP_MIN_MIN 0x1F8C
#define SYSMON_TEMP_MAX_MAX 0x1F90
+#define SYSMON_STATUS_RESET 0x1F94
#define SYSMON_TEMP_SAT_BASE 0x1FAC
#define SYSMON_MAX_REG 0x24C0
@@ -35,8 +50,12 @@ struct regmap;
#define SYSMON_SUPPLY_IDX_MAX 159
#define SYSMON_TEMP_SAT_MAX 64
+#define SYSMON_NO_OF_EVENTS 32
#define SYSMON_INTR_ALL_MASK GENMASK(31, 0)
+/* ISR/IMR temperature and OT alarm mask (bits 9:8) */
+#define SYSMON_TEMP_INTR_MASK GENMASK(9, 8)
+
/* Supply voltage conversion register fields */
#define SYSMON_MANTISSA_MASK GENMASK(15, 0)
#define SYSMON_FMT_MASK BIT(16)
@@ -46,11 +65,26 @@ struct regmap;
#define SYSMON_FRACTIONAL_SHIFT 7U
#define SYSMON_SUPPLY_MANTISSA_BITS 16
+/* Event address IDs for temp event channels */
+#define SYSMON_ADDR_TEMP_EVENT 160
+#define SYSMON_ADDR_OT_EVENT 161
+
+/* Bits per alarm register */
+#define SYSMON_ALARM_BITS_PER_REG 32
+
+#define SYSMON_UNMASK_WORK_DELAY_MS 500
+
/**
* struct sysmon - Driver data for Versal SysMon
* @regmap: register map for hardware access
* @lock: protects read-modify-write sequences on threshold registers
* and cached state that spans multiple regmap calls
+ * @irq_lock: protects interrupt mask register updates (MMIO path only)
+ * @masked_temp: currently masked temperature alarm bits
+ * @temp_mask: temperature interrupt configuration mask
+ * @temp_hysteresis: cached DEVICE_TEMP hysteresis in millicelsius
+ * @ot_hysteresis: cached OT hysteresis in millicelsius
+ * @sysmon_unmask_work: re-enables events after alarm condition clears
*/
struct sysmon {
struct regmap *regmap;
@@ -60,6 +94,17 @@ struct sysmon {
* that spans multiple regmap calls.
*/
struct mutex lock;
+ /*
+ * Protects interrupt mask register updates. Only used on the
+ * MMIO path (fast_io regmap); I2C has no IRQ and never reaches
+ * the event code that takes this lock.
+ */
+ spinlock_t irq_lock;
+ unsigned int masked_temp;
+ unsigned int temp_mask;
+ int temp_hysteresis;
+ int ot_hysteresis;
+ struct delayed_work sysmon_unmask_work;
};
int sysmon_core_probe(struct device *dev, struct regmap *regmap);
--
2.48.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH v5 4/5] iio: adc: versal-sysmon: add threshold event support
2026-06-08 18:38 ` [PATCH v5 4/5] iio: adc: versal-sysmon: add threshold event support Salih Erim
@ 2026-06-08 18:52 ` sashiko-bot
0 siblings, 0 replies; 9+ messages in thread
From: sashiko-bot @ 2026-06-08 18:52 UTC (permalink / raw)
To: Salih Erim; +Cc: robh, devicetree, conor+dt
Thank you for your contribution! Sashiko AI review found 8 potential issue(s) to consider:
- [High] The probe function unconditionally fails for devices without an IRQ, breaking I2C deployments.
- [High] `sysmon_write_event_value` overwrites the entire threshold register, incorrectly clearing upper bits.
- [High] The delayed worker blindly clears all pending hardware interrupts in the ISR register, causing unmasked hardware events to be permanently lost.
- [High] Missing 16-bit mask for negative temperature thresholds writes corrupted data (1s) to upper hardware register bits.
- [Medium] `sysmon_read_event_config` exposes transient internal polling mask state to userspace instead of the administrative state.
- [Medium] Unbounded user input from sysfs causes signed integer overflow in arithmetic conversions for temperature and voltage thresholds.
- [Medium] A race condition between `sysmon_write_event_config` and `sysmon_unmask_worker` can leave a disabled temperature interrupt enabled in hardware.
- [Medium] The driver will cause a 'scheduling while atomic' BUG on the I2C path if an interrupt is erroneously provided in the device tree.
--
commit 2275827bc141241d722cd6abd38d36f5e908731f
Author: Salih Erim <salih.erim@amd.com>
Subject: iio: adc: versal-sysmon: add threshold event support
This patch adds threshold event support for temperature and supply voltage
channels. The driver uses hysteresis mode for temperature and schedules a
delayed worker to poll for condition clear before unmasking.
> The interrupt handler masks active threshold interrupts (which are
> level-sensitive) and schedules a delayed worker to poll for condition
> clear before unmasking. When no hardware IRQ is available, event
> channels are not created and interrupt init is skipped, since the
> I2C regmap backend cannot be called from atomic context.
Does the unconditional check in sysmon_core_probe cause the probe to fail
on I2C devices instead of falling back to polled mode? The code aborts if
fwnode_irq_get returns a negative error code, which contradicts this part
of the commit message.
> diff --git a/drivers/iio/adc/versal-sysmon-core.c b/drivers/iio/adc/versal-sysmon-core.c
> index c7b5eecc93cfb..5fbd509089bbd 100644
> --- a/drivers/iio/adc/versal-sysmon-core.c
> +++ b/drivers/iio/adc/versal-sysmon-core.c
[ ... ]
> +static void sysmon_millicelsius_to_q8p7(u32 *raw_data, int val)
> +{
> + *raw_data = (val << SYSMON_FRACTIONAL_SHIFT) / (int)MILLI;
> +}
[Severity: Medium]
Could the arithmetic left shift overflow the 32-bit integer for large
user inputs?
[Severity: High]
If the division yields a negative signed integer for sub-zero temperatures,
does this result in an implicitly sign-extended 32-bit value that writes
1s to the upper 16 bits of the hardware register?
[ ... ]
> +static void sysmon_supply_processedtoraw(int val, u32 reg_val, u32 *raw_data)
> +{
> + int exponent = FIELD_GET(SYSMON_MODE_MASK, reg_val);
> + int format = FIELD_GET(SYSMON_FMT_MASK, reg_val);
> + int scale, tmp;
> +
> + scale = BIT(SYSMON_SUPPLY_MANTISSA_BITS - exponent);
> + tmp = (val * scale) / (int)MILLI;
[Severity: Medium]
Could this multiplication overflow a 32-bit signed integer if userspace
provides a moderately high voltage threshold?
[ ... ]
> +static int sysmon_read_event_config(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + enum iio_event_type type,
> + enum iio_event_direction dir)
> +{
> + u32 alarm_event_mask = sysmon_get_event_mask(chan->address);
> + struct sysmon *sysmon = iio_priv(indio_dev);
> + unsigned int imr;
> + int config_value;
> + int ret;
> +
> + ret = regmap_read(sysmon->regmap, SYSMON_IMR, &imr);
> + if (ret)
> + return ret;
> +
> + /* IMR bits are 1=masked, invert to get 1=enabled */
> + imr = ~imr;
> +
> + if (chan->type == IIO_VOLTAGE) {
> + config_value = sysmon_read_alarm_config(sysmon, chan->address);
> + if (config_value < 0)
> + return config_value;
> + return config_value && (imr & alarm_event_mask);
> + }
> +
> + return !!(imr & alarm_event_mask);
> +}
[Severity: Medium]
Does this expose the transient internal polling mask state from the
hardware instead of the persistent administrative state? If userspace
reads this during the 500ms delayed worker polling window, could it falsely
report that the interrupt is disabled?
[ ... ]
> +static int sysmon_write_event_config(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + enum iio_event_type type,
> + enum iio_event_direction dir,
> + bool state)
> +{
[ ... ]
> + if (chan->type == IIO_TEMP) {
> + if (state) {
> + ret = regmap_write(sysmon->regmap, SYSMON_IER, ier);
> + if (ret)
> + return ret;
> +
> + scoped_guard(spinlock_irq, &sysmon->irq_lock)
> + sysmon->temp_mask &= ~ier;
> + } else {
> + ret = regmap_write(sysmon->regmap, SYSMON_IDR, ier);
> + if (ret)
> + return ret;
> +
> + scoped_guard(spinlock_irq, &sysmon->irq_lock)
> + sysmon->temp_mask |= ier;
> + }
> + }
> +
> + return 0;
> +}
[Severity: Medium]
Is there a race condition here if sysmon_unmask_worker runs exactly
between the regmap_write to SYSMON_IDR and the spinlock acquisition?
Could the worker read the old sysmon->temp_mask and incorrectly re-enable
the interrupt in hardware?
[ ... ]
> +static int sysmon_write_event_value(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + enum iio_event_type type,
> + enum iio_event_direction dir,
> + enum iio_event_info info,
> + int val, int val2)
> +{
[ ... ]
> + if (chan->type == IIO_VOLTAGE) {
> + offset = sysmon_supply_thresh_offset(chan->address, dir);
> + if (offset < 0)
> + return offset;
> +
> + ret = regmap_read(sysmon->regmap, offset, ®_val);
> + if (ret)
> + return ret;
> +
> + sysmon_supply_processedtoraw(val, reg_val, &raw_val);
> +
> + return regmap_write(sysmon->regmap, offset, raw_val);
> + }
> +
> + return -EINVAL;
> +}
[Severity: High]
Does this overwrite the entire 32-bit threshold register with a
zero-extended 16-bit value? Since sysmon_supply_processedtoraw casts the
result to a u16 before assigning it to the u32 raw_val pointer, does
writing it back directly clear the upper 16 bits of the hardware register?
[ ... ]
> +static void sysmon_unmask_worker(struct work_struct *work)
> +{
> + struct sysmon *sysmon =
> + container_of(work, struct sysmon, sysmon_unmask_work.work);
> + unsigned int isr;
> +
> + /*
> + * regmap errors are not checked here because the worker and IRQ
> + * handler cannot propagate errors. The MMIO regmap uses fast_io
> + * with direct readl/writel which cannot fail.
> + */
> + spin_lock_irq(&sysmon->irq_lock);
> + regmap_read(sysmon->regmap, SYSMON_ISR, &isr);
> + regmap_write(sysmon->regmap, SYSMON_ISR, isr);
> + sysmon_unmask_temp(sysmon, isr);
> + spin_unlock_irq(&sysmon->irq_lock);
[Severity: High]
Does writing the exact read value back to the write-1-to-clear SYSMON_ISR
register permanently clear all pending hardware interrupts? If a supply
voltage alarm triggers just before this runs, could it be silently dropped
since the worker only processes temperature bits?
[ ... ]
> +static irqreturn_t sysmon_iio_irq(int irq, void *data)
> +{
> + struct iio_dev *indio_dev = data;
> + struct sysmon *sysmon = iio_priv(indio_dev);
> + unsigned int isr, imr;
> +
> + guard(spinlock)(&sysmon->irq_lock);
> +
> + regmap_read(sysmon->regmap, SYSMON_ISR, &isr);
[Severity: Medium]
Will this cause a scheduling while atomic bug on the I2C path if an
interrupt is erroneously provided in the device tree? Since sysmon_core_probe
unconditionally accepts the IRQ, and this handler uses a spinlock while
performing a regmap_read, could the I2C transfer function attempt to take
a mutex in atomic context?
[ ... ]
> @@ -269,13 +904,40 @@ int sysmon_core_probe(struct device *dev, struct regmap *regmap)
> if (ret)
> return ret;
>
> + irq = fwnode_irq_get(dev_fwnode(dev), 0);
> + if (irq < 0)
> + return dev_err_probe(dev, irq, "failed to get IRQ\n");
[Severity: High]
Does this unconditional check cause the probe to fail on I2C devices instead
of falling back to polled mode?
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260608183801.1257051-1-salih.erim@amd.com?part=4
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v5 5/5] iio: adc: versal-sysmon: add oversampling support
2026-06-08 18:37 [PATCH v5 0/5] iio: adc: add AMD/Xilinx Versal SysMon driver Salih Erim
` (3 preceding siblings ...)
2026-06-08 18:38 ` [PATCH v5 4/5] iio: adc: versal-sysmon: add threshold event support Salih Erim
@ 2026-06-08 18:38 ` Salih Erim
2026-06-08 18:49 ` sashiko-bot
4 siblings, 1 reply; 9+ messages in thread
From: Salih Erim @ 2026-06-08 18:38 UTC (permalink / raw)
To: jic23, andy
Cc: dlechner, nuno.sa, robh, krzk+dt, conor+dt, conall.ogriofa,
michal.simek, linux, erimsalih, linux-iio, devicetree,
linux-kernel, Salih Erim
Add support for reading and writing the oversampling ratio through
the IIO oversampling_ratio attribute. The hardware supports averaging
2, 4, 8, or 16 samples, plus a ratio of 1 (no averaging).
Temperature and supply channels share oversampling configuration at
the type level (all temperature channels share one ratio, all supply
channels share another), exposed through info_mask_shared_by_type.
The hardware encoding uses sample_count / 2 in a 4-bit field within
the CONFIG register. Per-channel averaging enable registers must also
be updated to activate or deactivate averaging.
Signed-off-by: Salih Erim <salih.erim@amd.com>
---
Changes in v5:
- Remove unneeded parentheses in i * SYSMON_REG_STRIDE (Andy)
- Use struct regmap *map local variable in
sysmon_set_avg_enable (Andy)
- switch instead of redundant if/if on channel_type (Andy)
- Add CONFIG register readback fence after oversampling update
to prevent NoC bus hang from posted writes (found during
hardware stress testing)
Changes in v4:
- Return directly from sysmon_set_avg_enable calls, remove
else after early returns, drop unreachable return 0 (Jonathan)
- Rename mask defines to SYSMON_CONFIG_SUPPLY_OSR and
SYSMON_CONFIG_TEMP_SAT_OSR (Jonathan)
- Drop "bits X:Y" from GENMASK comments (Jonathan)
- Blank lines after if (ret) return ret blocks (Jonathan)
- Move oversampling read inside guard(mutex) scope
Changes in v3:
- No changes
Changes in v2:
- EN_AVG per-channel bitmask registers written with all-ones
instead of boolean 1 when oversampling is enabled
- EN_AVG write errors propagated to userspace
- Oversampling limited to satellite temp and supply channels;
static temp channels do not participate
- Oversampling exposes actual sample counts (1,2,4,8,16) to
userspace with internal HW register translation
- write_raw_get_fmt returns IIO_VAL_INT for oversampling ratio
- HW encoding documented (sample_count/2, not log2)
- oversampling_avail is const int[] (type match fix)
drivers/iio/adc/versal-sysmon-core.c | 147 ++++++++++++++++++++++++++-
drivers/iio/adc/versal-sysmon.h | 17 ++++
2 files changed, 163 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/adc/versal-sysmon-core.c b/drivers/iio/adc/versal-sysmon-core.c
index 5fbd509089b..389a8887811 100644
--- a/drivers/iio/adc/versal-sysmon-core.c
+++ b/drivers/iio/adc/versal-sysmon-core.c
@@ -26,6 +26,12 @@
#include "versal-sysmon.h"
+/*
+ * Oversampling ratio values exposed to userspace via IIO.
+ * Actual number of samples averaged: 1=none, 2=2x, 4=4x, 8=8x, 16=16x.
+ */
+static const int sysmon_oversampling_avail[] = { 1, 2, 4, 8, 16 };
+
/* OT and TEMP hysteresis mode bits in SYSMON_TEMP_EV_CFG */
#define SYSMON_OT_HYST_MASK BIT(0)
#define SYSMON_TEMP_HYST_MASK BIT(1)
@@ -194,6 +200,12 @@ static int sysmon_read_raw(struct iio_dev *indio_dev,
guard(mutex)(&sysmon->lock);
+ if (mask == IIO_CHAN_INFO_OVERSAMPLING_RATIO) {
+ *val = (chan->type == IIO_TEMP) ? sysmon->temp_oversampling :
+ sysmon->supply_oversampling;
+ return IIO_VAL_INT;
+ }
+
switch (chan->type) {
case IIO_TEMP:
if (mask == IIO_CHAN_INFO_SCALE) {
@@ -496,6 +508,127 @@ static int sysmon_write_event_value(struct iio_dev *indio_dev,
return -EINVAL;
}
+static int sysmon_set_avg_enable(struct sysmon *sysmon,
+ u32 base, u32 count, u32 val)
+{
+ struct regmap *map = sysmon->regmap;
+ int ret;
+
+ for (unsigned int i = 0; i < count; i++) {
+ ret = regmap_write(map, base + i * SYSMON_REG_STRIDE, val);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int sysmon_osr_write(struct sysmon *sysmon, int channel_type, int val)
+{
+ /*
+ * HW register encoding is sample_count / 2:
+ * 0=none, 1=2x, 2=4x, 4=8x, 8=16x (not log2-based).
+ */
+ int hw_val = val >> 1;
+ unsigned int readback;
+ int ret;
+
+ switch (channel_type) {
+ case IIO_TEMP:
+ ret = regmap_update_bits(sysmon->regmap, SYSMON_CONFIG,
+ SYSMON_CONFIG_TEMP_SAT_OSR,
+ FIELD_PREP(SYSMON_CONFIG_TEMP_SAT_OSR,
+ hw_val));
+ if (ret)
+ return ret;
+
+ /*
+ * Readback fence: the SysMon CONFIG register resides in the
+ * PMC domain behind the NoC. A posted write may not reach the
+ * hardware before the next MMIO access. Reading the register
+ * back forces the interconnect to complete the write, preventing
+ * a bus hang on the subsequent access.
+ */
+ regmap_read(sysmon->regmap, SYSMON_CONFIG, &readback);
+
+ return sysmon_set_avg_enable(sysmon, SYSMON_TEMP_EN_AVG_BASE,
+ SYSMON_TEMP_EN_AVG_COUNT,
+ hw_val ? ~0U : 0);
+ case IIO_VOLTAGE:
+ ret = regmap_update_bits(sysmon->regmap, SYSMON_CONFIG,
+ SYSMON_CONFIG_SUPPLY_OSR,
+ FIELD_PREP(SYSMON_CONFIG_SUPPLY_OSR,
+ hw_val));
+ if (ret)
+ return ret;
+
+ /* Readback fence -- see above */
+ regmap_read(sysmon->regmap, SYSMON_CONFIG, &readback);
+
+ return sysmon_set_avg_enable(sysmon, SYSMON_SUPPLY_EN_AVG_BASE,
+ SYSMON_SUPPLY_EN_AVG_COUNT,
+ hw_val ? ~0U : 0);
+ default:
+ return -EINVAL;
+ }
+}
+
+static int sysmon_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct sysmon *sysmon = iio_priv(indio_dev);
+ int i, ret;
+
+ if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
+ return -EINVAL;
+
+ for (i = 0; i < ARRAY_SIZE(sysmon_oversampling_avail); i++) {
+ if (val == sysmon_oversampling_avail[i])
+ break;
+ }
+ if (i == ARRAY_SIZE(sysmon_oversampling_avail))
+ return -EINVAL;
+
+ guard(mutex)(&sysmon->lock);
+
+ ret = sysmon_osr_write(sysmon, chan->type, val);
+ if (ret)
+ return ret;
+
+ if (chan->type == IIO_TEMP)
+ sysmon->temp_oversampling = val;
+ else
+ sysmon->supply_oversampling = val;
+
+ return 0;
+}
+
+static int sysmon_write_raw_get_fmt(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ long mask)
+{
+ if (mask == IIO_CHAN_INFO_OVERSAMPLING_RATIO)
+ return IIO_VAL_INT;
+
+ return -EINVAL;
+}
+
+static int sysmon_read_avail(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ const int **vals, int *type,
+ int *length, long mask)
+{
+ if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
+ return -EINVAL;
+
+ *vals = sysmon_oversampling_avail;
+ *type = IIO_VAL_INT;
+ *length = ARRAY_SIZE(sysmon_oversampling_avail);
+
+ return IIO_AVAIL_LIST;
+}
+
static int sysmon_read_label(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
char *label)
@@ -508,6 +641,9 @@ static int sysmon_read_label(struct iio_dev *indio_dev,
static const struct iio_info sysmon_iio_info = {
.read_raw = sysmon_read_raw,
+ .write_raw = sysmon_write_raw,
+ .write_raw_get_fmt = sysmon_write_raw_get_fmt,
+ .read_avail = sysmon_read_avail,
.read_label = sysmon_read_label,
.read_event_config = sysmon_read_event_config,
.write_event_config = sysmon_write_event_config,
@@ -811,6 +947,10 @@ static int sysmon_parse_fw(struct iio_dev *indio_dev, struct device *dev,
.address = reg,
.info_mask_separate =
BIT(IIO_CHAN_INFO_PROCESSED),
+ .info_mask_shared_by_type =
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+ .info_mask_shared_by_type_available =
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
.event_spec = irq > 0 ?
sysmon_supply_events : NULL,
.num_event_specs = irq > 0 ?
@@ -843,7 +983,10 @@ static int sysmon_parse_fw(struct iio_dev *indio_dev, struct device *dev,
(reg - 1) * SYSMON_REG_STRIDE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type =
- BIT(IIO_CHAN_INFO_SCALE),
+ BIT(IIO_CHAN_INFO_SCALE) |
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+ .info_mask_shared_by_type_available =
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
.datasheet_name = label,
};
}
@@ -890,6 +1033,8 @@ int sysmon_core_probe(struct device *dev, struct regmap *regmap)
sysmon = iio_priv(indio_dev);
sysmon->regmap = regmap;
+ sysmon->temp_oversampling = 1;
+ sysmon->supply_oversampling = 1;
ret = devm_mutex_init(dev, &sysmon->lock);
if (ret)
diff --git a/drivers/iio/adc/versal-sysmon.h b/drivers/iio/adc/versal-sysmon.h
index b5861f7e882..ad97ff699dc 100644
--- a/drivers/iio/adc/versal-sysmon.h
+++ b/drivers/iio/adc/versal-sysmon.h
@@ -24,11 +24,13 @@ struct regmap;
#define SYSMON_IMR 0x0048
#define SYSMON_IER 0x004C
#define SYSMON_IDR 0x0050
+#define SYSMON_CONFIG 0x0100
#define SYSMON_TEMP_MAX 0x1030
#define SYSMON_TEMP_MIN 0x1034
#define SYSMON_SUPPLY_BASE 0x1040
#define SYSMON_ALARM_FLAG 0x1018
#define SYSMON_ALARM_REG 0x1940
+#define SYSMON_SUPPLY_EN_AVG_BASE 0x1958
#define SYSMON_TEMP_TH_LOW 0x1970
#define SYSMON_TEMP_TH_UP 0x1974
#define SYSMON_OT_TH_LOW 0x1978
@@ -40,6 +42,7 @@ struct regmap;
#define SYSMON_TEMP_MAX_MAX 0x1F90
#define SYSMON_STATUS_RESET 0x1F94
#define SYSMON_TEMP_SAT_BASE 0x1FAC
+#define SYSMON_TEMP_EN_AVG_BASE 0x24B4
#define SYSMON_MAX_REG 0x24C0
/* NPI unlock value written to SYSMON_NPI_LOCK */
@@ -56,6 +59,16 @@ struct regmap;
/* ISR/IMR temperature and OT alarm mask (bits 9:8) */
#define SYSMON_TEMP_INTR_MASK GENMASK(9, 8)
+/* SYSMON_CONFIG: supply oversampling ratio */
+#define SYSMON_CONFIG_SUPPLY_OSR GENMASK(17, 14)
+
+/* SYSMON_CONFIG: temperature satellite oversampling ratio */
+#define SYSMON_CONFIG_TEMP_SAT_OSR GENMASK(27, 24)
+
+/* Per-channel averaging enable register counts */
+#define SYSMON_SUPPLY_EN_AVG_COUNT 5
+#define SYSMON_TEMP_EN_AVG_COUNT 2
+
/* Supply voltage conversion register fields */
#define SYSMON_MANTISSA_MASK GENMASK(15, 0)
#define SYSMON_FMT_MASK BIT(16)
@@ -85,6 +98,8 @@ struct regmap;
* @temp_hysteresis: cached DEVICE_TEMP hysteresis in millicelsius
* @ot_hysteresis: cached OT hysteresis in millicelsius
* @sysmon_unmask_work: re-enables events after alarm condition clears
+ * @temp_oversampling: current temp oversampling ratio
+ * @supply_oversampling: current supply oversampling ratio
*/
struct sysmon {
struct regmap *regmap;
@@ -105,6 +120,8 @@ struct sysmon {
int temp_hysteresis;
int ot_hysteresis;
struct delayed_work sysmon_unmask_work;
+ unsigned int temp_oversampling;
+ unsigned int supply_oversampling;
};
int sysmon_core_probe(struct device *dev, struct regmap *regmap);
--
2.48.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH v5 5/5] iio: adc: versal-sysmon: add oversampling support
2026-06-08 18:38 ` [PATCH v5 5/5] iio: adc: versal-sysmon: add oversampling support Salih Erim
@ 2026-06-08 18:49 ` sashiko-bot
0 siblings, 0 replies; 9+ messages in thread
From: sashiko-bot @ 2026-06-08 18:49 UTC (permalink / raw)
To: Salih Erim; +Cc: robh, devicetree, conor+dt
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The oversampling ratio software caches are initialized to 1 without synchronizing with the actual hardware state during probe.
--
commit 3a6a43bb24f0fd6d80e623d9f51baca549ff9147
Author: Salih Erim <salih.erim@amd.com>
iio: adc: versal-sysmon: add oversampling support
This commit adds support for reading and writing the oversampling ratio
through the IIO oversampling_ratio attribute. The hardware supports averaging
2, 4, 8, or 16 samples, plus a ratio of 1 (no averaging).
> diff --git a/drivers/iio/adc/versal-sysmon-core.c b/drivers/iio/adc/versal-sysmon-core.c
> index 5fbd509089bbd..389a88878115f 100644
> --- a/drivers/iio/adc/versal-sysmon-core.c
> +++ b/drivers/iio/adc/versal-sysmon-core.c
[ ... ]
> @@ -890,6 +1033,8 @@ int sysmon_core_probe(struct device *dev, struct regmap *regmap)
>
> sysmon = iio_priv(indio_dev);
> sysmon->regmap = regmap;
> + sysmon->temp_oversampling = 1;
> + sysmon->supply_oversampling = 1;
[Severity: Medium]
Is it possible that the hardware was already configured with a different
oversampling ratio by the bootloader (FSBL) or retained state across a warm
reboot?
The software cache is initialized to 1 here, but no corresponding hardware
synchronization or explicit register initialization occurs before the IIO
device is registered.
If the hardware is actively using averaging (e.g., OSR=16), could the IIO
sysfs interface incorrectly report 1, masking the true hardware configuration?
Would it be safer to either enforce this default state on the hardware or read
the current register values during initialization?
>
> ret = devm_mutex_init(dev, &sysmon->lock);
> if (ret)
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260608183801.1257051-1-salih.erim@amd.com?part=5
^ permalink raw reply [flat|nested] 9+ messages in thread