* [PATCH v3 3/4] hwmon: Add Microchip LAN969x fan controller driver
2026-11-11 16:12 [PATCH v3 1/4] dt-bindings: hwmon: fan-common: reject zero pulses per revolution Robert Marko
2026-11-11 16:12 ` [PATCH v3 2/4] dt-bindings: hwmon: add Microchip LAN969x fan controller Robert Marko
@ 2026-11-11 16:12 ` Robert Marko
2026-11-11 16:12 ` [PATCH v3 4/4] arm64: dts: microchip: lan969x: add fan controller Robert Marko
2026-11-12 1:05 ` [PATCH v3 1/4] dt-bindings: hwmon: fan-common: reject zero pulses per revolution Rob Herring
3 siblings, 0 replies; 6+ messages in thread
From: Robert Marko @ 2026-11-11 16:12 UTC (permalink / raw)
To: linux, robh, krzk+dt, conor+dt, corbet, skhan, rdunlap,
nicolas.ferre, claudiu.beznea, linux-hwmon, devicetree,
linux-kernel, linux-doc, linux-arm-kernel
Cc: luka.perkov, Robert Marko
The LAN969x fan controller has its own register block, separate
from the Sparx5-compatible temperature sensor.
Add a dedicated hwmon driver for tachometer, PWM, and thermal cooling.
Signed-off-by: Robert Marko <robert.marko@sartura.hr>
---
Changes in v3:
- Use a standalone fan driver instead of extending sparx5-temp.
- Combine tachometer, PWM and thermal cooling support in one patch.
- Reject a zero-rate fan clock during probe.
- Add a dedicated MAINTAINERS entry.
Changes in v2:
- Register fan and temperature monitoring as separate hwmon devices.
- Reject a present but malformed pulses-per-revolution property.
- Drop the private mutex; hwmon serializes sysfs accesses.
- Preserve firmware PWM polarity when no fan child is present.
- Convert the DT period directly to a divider and reject invalid values
before changing fan registers.
- Use hwmon_lock() for cooling callbacks instead of a private mutex.
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/lan969x-fan.rst | 53 ++++
MAINTAINERS | 8 +
drivers/hwmon/Kconfig | 10 +
drivers/hwmon/Makefile | 1 +
drivers/hwmon/lan969x-fan.c | 444 ++++++++++++++++++++++++++++
6 files changed, 517 insertions(+)
create mode 100644 Documentation/hwmon/lan969x-fan.rst
create mode 100644 drivers/hwmon/lan969x-fan.c
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index a8ea421128b50..aa84893729fac 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -122,6 +122,7 @@ Hardware Monitoring Kernel Drivers
kbatt
kfan
lan966x
+ lan969x-fan
lattepanda-sigma-ec
lineage-pem
lm25066
diff --git a/Documentation/hwmon/lan969x-fan.rst b/Documentation/hwmon/lan969x-fan.rst
new file mode 100644
index 0000000000000..c79d8eadbc158
--- /dev/null
+++ b/Documentation/hwmon/lan969x-fan.rst
@@ -0,0 +1,53 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+Microchip LAN969x fan controller
+================================
+
+Supported chips:
+
+ * Microchip LAN969x
+
+ Prefix: 'lan969x_fan'
+
+ Addresses scanned: -
+
+ Datasheet: https://microchip-ung.github.io/lan969x-industrial_reginfo/
+
+Description
+-----------
+
+The LAN969x fan controller provides a tachometer input and a PWM output.
+
+The tachometer counts pulses over one-second intervals, independently of the
+PWM output. The fan child's pulses-per-revolution property specifies how many
+pulses represent one revolution; it defaults to two.
+
+The fan child's pwms property selects the initial PWM period and polarity.
+The output is dedicated to this fan and is not available to external PWM
+consumers. The pwm1 value describes the logical duty cycle independently of
+the output polarity. Frequency requests are rounded to the nearest hardware
+divider value; requests outside the divider range are rejected. pwm1_freq
+reports the resulting frequency.
+
+Sysfs entries
+-------------
+
+======================= ========================================================
+fan1_input Fan speed in RPM.
+pwm1 PWM duty cycle, from 0 to 255.
+pwm1_freq PWM frequency in Hz.
+======================= ========================================================
+
+Thermal cooling
+---------------
+
+With device-tree thermal support enabled, the fan can also act as a thermal
+cooling device. The fan child's cooling-levels property maps cooling states
+to PWM values from 0 to 255, in ascending order. When cooling levels are
+provided, the driver initially selects the highest level.
+
+Manual pwm1 writes remain available and update the reported cooling state
+to the highest state whose PWM value does not exceed the requested value,
+or state zero if the value is below the first level. Subsequent thermal
+cooling requests can override manual PWM settings. Each cooling request
+programs the exact PWM value associated with the requested state.
diff --git a/MAINTAINERS b/MAINTAINERS
index aa647f5d37ddb..bc8af689ce9b2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18369,6 +18369,14 @@ L: netdev@vger.kernel.org
S: Maintained
F: drivers/net/ethernet/microchip/sparx5/lan969x/*
+MICROCHIP LAN969X FAN CONTROLLER DRIVER
+M: Robert Marko <robert.marko@sartura.hr>
+L: linux-hwmon@vger.kernel.org
+S: Maintained
+F: Documentation/devicetree/bindings/hwmon/microchip,lan9691-fan.yaml
+F: Documentation/hwmon/lan969x-fan.rst
+F: drivers/hwmon/lan969x-fan.c
+
MICROCHIP LCDFB DRIVER
M: Nicolas Ferre <nicolas.ferre@microchip.com>
L: linux-fbdev@vger.kernel.org
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 3ae676a56d95c..634e174eb4d8b 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1060,6 +1060,16 @@ config SENSORS_LAN966X
This driver can also be built as a module. If so, the module
will be called lan966x-hwmon.
+config SENSORS_LAN969X_FAN
+ tristate "Microchip LAN969x fan controller"
+ depends on ARCH_LAN969X || COMPILE_TEST
+ help
+ If you say yes here you get support for the fan controller on
+ Microchip LAN969x SoCs.
+
+ This driver can also be built as a module. If so, the module
+ will be called lan969x-fan.
+
config SENSORS_LATTEPANDA_SIGMA_EC
tristate "LattePanda Sigma EC hardware monitoring"
depends on X86
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index be3eb0992a0d0..3d54ead07f0b4 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -122,6 +122,7 @@ obj-$(CONFIG_SENSORS_KB9002) += kb9002.o
obj-$(CONFIG_SENSORS_KBATT) += kbatt.o
obj-$(CONFIG_SENSORS_KFAN) += kfan.o
obj-$(CONFIG_SENSORS_LAN966X) += lan966x-hwmon.o
+obj-$(CONFIG_SENSORS_LAN969X_FAN) += lan969x-fan.o
obj-$(CONFIG_SENSORS_LATTEPANDA_SIGMA_EC) += lattepanda-sigma-ec.o
obj-$(CONFIG_SENSORS_LENOVO_EC) += lenovo-ec-sensors.o
obj-$(CONFIG_SENSORS_LINEAGE) += lineage-pem.o
diff --git a/drivers/hwmon/lan969x-fan.c b/drivers/hwmon/lan969x-fan.c
new file mode 100644
index 0000000000000..fae0248658818
--- /dev/null
+++ b/drivers/hwmon/lan969x-fan.c
@@ -0,0 +1,444 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Microchip LAN969x fan controller driver */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/hwmon.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/thermal.h>
+
+#include <dt-bindings/pwm/pwm.h>
+
+#define FAN_CFG 0
+#define FAN_CFG_DUTY_CYCLE GENMASK(23, 16)
+#define FAN_CFG_INV_POL BIT(3)
+#define FAN_CFG_GATE_ENA BIT(2)
+#define FAN_CFG_STAT_MODE BIT(0)
+#define FAN_PWM_FREQ 4
+#define FAN_PWM_FREQ_CYCLES GENMASK(27, 16)
+#define FAN_PWM_FREQ_DIV GENMASK(15, 0)
+#define FAN_CNT 8
+#define FAN_CNT_DATA GENMASK(15, 0)
+
+#define FAN_TACH_INTERVAL_HZ 100000
+#define FAN_PWM_FREQ_SCALE 256
+
+struct lan969x_fan {
+ void __iomem *base;
+ struct clk *clk;
+ struct device *hwmon_dev;
+ unsigned long clk_rate;
+ u32 pulses_per_revolution;
+ u32 pwm_period;
+ bool pwm_inverted;
+ u32 *cooling_levels;
+ unsigned long cooling_state;
+ unsigned long max_cooling_state;
+};
+
+static void lan969x_fan_enable(struct lan969x_fan *fan)
+{
+ u32 cycles, val;
+
+ cycles = DIV_ROUND_CLOSEST(fan->clk_rate, FAN_TACH_INTERVAL_HZ);
+ cycles = clamp_val(cycles, 1, FIELD_MAX(FAN_PWM_FREQ_CYCLES));
+
+ val = readl(fan->base + FAN_PWM_FREQ);
+ val &= ~FAN_PWM_FREQ_CYCLES;
+ val |= FIELD_PREP(FAN_PWM_FREQ_CYCLES, cycles);
+ writel(val, fan->base + FAN_PWM_FREQ);
+
+ /* Count all tachometer pulses over one-second intervals. */
+ val = readl(fan->base + FAN_CFG);
+ val &= ~(FAN_CFG_STAT_MODE | FAN_CFG_GATE_ENA);
+ if (fan->pwm_period) {
+ val &= ~FAN_CFG_INV_POL;
+ if (fan->pwm_inverted)
+ val |= FAN_CFG_INV_POL;
+ }
+ writel(val, fan->base + FAN_CFG);
+}
+
+static void lan969x_fan_update_cooling_state(struct lan969x_fan *fan, u32 pwm)
+{
+ unsigned long state;
+
+ if (!fan->cooling_levels)
+ return;
+
+ for (state = 0; state < fan->max_cooling_state; state++)
+ if (pwm < fan->cooling_levels[state + 1])
+ break;
+
+ fan->cooling_state = state;
+}
+
+static int lan969x_fan_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct lan969x_fan *fan = dev_get_drvdata(dev);
+ unsigned long rate;
+ u32 data;
+
+ switch (type) {
+ case hwmon_fan:
+ if (attr != hwmon_fan_input)
+ break;
+ data = readl_relaxed(fan->base + FAN_CNT);
+ data = FIELD_GET(FAN_CNT_DATA, data);
+ *val = data * 60 / fan->pulses_per_revolution;
+ return 0;
+ case hwmon_pwm:
+ switch (attr) {
+ case hwmon_pwm_input:
+ data = readl_relaxed(fan->base + FAN_CFG);
+ *val = FIELD_GET(FAN_CFG_DUTY_CYCLE, data);
+ return 0;
+ case hwmon_pwm_freq:
+ data = readl_relaxed(fan->base + FAN_PWM_FREQ);
+ data = FIELD_GET(FAN_PWM_FREQ_DIV, data);
+ if (!data)
+ return -ENODATA;
+
+ rate = DIV_ROUND_CLOSEST(fan->clk_rate,
+ FAN_PWM_FREQ_SCALE);
+ *val = DIV_ROUND_CLOSEST(rate, data);
+ return 0;
+ default:
+ break;
+ }
+ break;
+ default:
+ break;
+ }
+
+ return -EOPNOTSUPP;
+}
+
+static void lan969x_fan_set_pwm(struct lan969x_fan *fan, u32 pwm)
+{
+ u32 data;
+
+ data = readl_relaxed(fan->base + FAN_CFG);
+ data &= ~FAN_CFG_DUTY_CYCLE;
+ data |= FIELD_PREP(FAN_CFG_DUTY_CYCLE, pwm);
+ writel_relaxed(data, fan->base + FAN_CFG);
+}
+
+static int lan969x_fan_write_pwm(struct lan969x_fan *fan, long val)
+{
+ if (val < 0 || val > 255)
+ return -EINVAL;
+
+ lan969x_fan_set_pwm(fan, val);
+ lan969x_fan_update_cooling_state(fan, val);
+
+ return 0;
+}
+
+static void lan969x_fan_write_pwm_divider(struct lan969x_fan *fan, u32 divider)
+{
+ u32 data;
+
+ data = readl_relaxed(fan->base + FAN_PWM_FREQ);
+ data &= ~FAN_PWM_FREQ_DIV;
+ data |= FIELD_PREP(FAN_PWM_FREQ_DIV, divider);
+ writel_relaxed(data, fan->base + FAN_PWM_FREQ);
+}
+
+static int lan969x_fan_write_pwm_period(struct lan969x_fan *fan)
+{
+ unsigned long rate;
+ u64 divider;
+
+ rate = DIV_ROUND_CLOSEST(fan->clk_rate, FAN_PWM_FREQ_SCALE);
+ divider = DIV_ROUND_CLOSEST_ULL((u64)rate * fan->pwm_period,
+ NSEC_PER_SEC);
+ if (!divider || divider > FIELD_MAX(FAN_PWM_FREQ_DIV))
+ return -ERANGE;
+
+ lan969x_fan_write_pwm_divider(fan, divider);
+
+ return 0;
+}
+
+static int lan969x_fan_write_pwm_freq(struct lan969x_fan *fan, long val)
+{
+ unsigned long rate, divider;
+
+ if (val <= 0)
+ return -EINVAL;
+
+ rate = DIV_ROUND_CLOSEST(fan->clk_rate, FAN_PWM_FREQ_SCALE);
+ if (val < DIV_ROUND_CLOSEST(rate, FIELD_MAX(FAN_PWM_FREQ_DIV)) ||
+ val > rate)
+ return -ERANGE;
+
+ divider = DIV_ROUND_CLOSEST(rate, val);
+ divider = min_t(unsigned long, divider, FIELD_MAX(FAN_PWM_FREQ_DIV));
+
+ lan969x_fan_write_pwm_divider(fan, divider);
+
+ return 0;
+}
+
+static int lan969x_fan_write(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long val)
+{
+ struct lan969x_fan *fan = dev_get_drvdata(dev);
+
+ if (type != hwmon_pwm)
+ return -EOPNOTSUPP;
+
+ switch (attr) {
+ case hwmon_pwm_input:
+ return lan969x_fan_write_pwm(fan, val);
+ case hwmon_pwm_freq:
+ return lan969x_fan_write_pwm_freq(fan, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static umode_t lan969x_fan_is_visible(const void *_data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ switch (type) {
+ case hwmon_fan:
+ return attr == hwmon_fan_input ? 0444 : 0;
+ case hwmon_pwm:
+ if (attr == hwmon_pwm_input || attr == hwmon_pwm_freq)
+ return 0644;
+ return 0;
+ default:
+ return 0;
+ }
+}
+
+static const struct hwmon_channel_info * const lan969x_fan_info[] = {
+ HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
+ HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_FREQ),
+ NULL
+};
+
+static const struct hwmon_ops lan969x_fan_hwmon_ops = {
+ .is_visible = lan969x_fan_is_visible,
+ .read = lan969x_fan_read,
+ .write = lan969x_fan_write,
+};
+
+static const struct hwmon_chip_info lan969x_fan_chip_info = {
+ .ops = &lan969x_fan_hwmon_ops,
+ .info = lan969x_fan_info,
+};
+
+static int lan969x_fan_cooling_get_max_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ struct lan969x_fan *fan = cdev->devdata;
+
+ *state = fan->max_cooling_state;
+
+ return 0;
+}
+
+static int lan969x_fan_cooling_get_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ struct lan969x_fan *fan = cdev->devdata;
+
+ hwmon_lock(fan->hwmon_dev);
+ *state = fan->cooling_state;
+ hwmon_unlock(fan->hwmon_dev);
+
+ return 0;
+}
+
+static int lan969x_fan_cooling_set_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long state)
+{
+ struct lan969x_fan *fan = cdev->devdata;
+
+ if (state > fan->max_cooling_state)
+ return -EINVAL;
+
+ hwmon_lock(fan->hwmon_dev);
+ lan969x_fan_set_pwm(fan, fan->cooling_levels[state]);
+ fan->cooling_state = state;
+ hwmon_unlock(fan->hwmon_dev);
+
+ return 0;
+}
+
+static const struct thermal_cooling_device_ops lan969x_fan_cooling_ops = {
+ .get_max_state = lan969x_fan_cooling_get_max_state,
+ .get_cur_state = lan969x_fan_cooling_get_cur_state,
+ .set_cur_state = lan969x_fan_cooling_set_cur_state,
+};
+
+static int lan969x_fan_get_cooling_data(struct device *dev,
+ struct device_node *fan_np,
+ struct lan969x_fan *fan)
+{
+ u32 *levels;
+ int count, i, ret;
+
+ if (!of_property_present(fan_np, "cooling-levels"))
+ return 0;
+
+ count = of_property_count_u32_elems(fan_np, "cooling-levels");
+ if (count <= 0)
+ return dev_err_probe(dev, count ? : -EINVAL,
+ "invalid cooling-levels property\n");
+
+ levels = devm_kcalloc(dev, count, sizeof(*levels), GFP_KERNEL);
+ if (!levels)
+ return -ENOMEM;
+ fan->cooling_levels = levels;
+
+ ret = of_property_read_u32_array(fan_np, "cooling-levels",
+ fan->cooling_levels, count);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "failed to read cooling-levels\n");
+
+ for (i = 0; i < count; i++) {
+ if (fan->cooling_levels[i] > 255)
+ return dev_err_probe(dev, -EINVAL,
+ "cooling level %d exceeds 255\n", i);
+ if (i && fan->cooling_levels[i] < fan->cooling_levels[i - 1])
+ return dev_err_probe(dev, -EINVAL,
+ "cooling levels must be ascending\n");
+ }
+
+ fan->max_cooling_state = count - 1;
+
+ return 0;
+}
+
+static int lan969x_fan_get_fan_data(struct device *dev,
+ struct device_node *fan_np,
+ struct lan969x_fan *fan)
+{
+ struct of_phandle_args args;
+ int ret;
+
+ ret = of_parse_phandle_with_args(fan_np, "pwms", "#pwm-cells", 0,
+ &args);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to parse fan PWM\n");
+
+ if (args.np != dev->of_node || args.args_count != 2 || !args.args[0] ||
+ args.args[1] & ~PWM_POLARITY_INVERTED) {
+ of_node_put(args.np);
+ return dev_err_probe(dev, -EINVAL, "invalid fan PWM specifier\n");
+ }
+
+ fan->pwm_period = args.args[0];
+ fan->pwm_inverted = args.args[1] & PWM_POLARITY_INVERTED;
+ of_node_put(args.np);
+
+ if (of_property_present(fan_np, "pulses-per-revolution")) {
+ ret = of_property_read_u32(fan_np, "pulses-per-revolution",
+ &fan->pulses_per_revolution);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "invalid pulses-per-revolution\n");
+ }
+ if (!fan->pulses_per_revolution || fan->pulses_per_revolution > 4)
+ return dev_err_probe(dev, -EINVAL,
+ "invalid pulses-per-revolution\n");
+
+ return lan969x_fan_get_cooling_data(dev, fan_np, fan);
+}
+
+static int lan969x_fan_probe(struct platform_device *pdev)
+{
+ struct thermal_cooling_device *cdev;
+ struct device *dev = &pdev->dev;
+ struct lan969x_fan *fan;
+ struct device_node *fan_np __free(device_node) = NULL;
+ u32 initial_pwm;
+ int ret;
+
+ fan = devm_kzalloc(dev, sizeof(*fan), GFP_KERNEL);
+ if (!fan)
+ return -ENOMEM;
+
+ fan->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(fan->base))
+ return PTR_ERR(fan->base);
+
+ fan->pulses_per_revolution = 2;
+ fan_np = of_get_available_child_by_name(dev->of_node, "fan");
+ if (fan_np) {
+ ret = lan969x_fan_get_fan_data(dev, fan_np, fan);
+ if (ret)
+ return ret;
+ }
+
+ fan->clk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(fan->clk))
+ return PTR_ERR(fan->clk);
+ fan->clk_rate = clk_get_rate(fan->clk);
+ if (!fan->clk_rate)
+ return dev_err_probe(dev, -EINVAL, "invalid fan clock rate\n");
+
+ if (fan->pwm_period) {
+ ret = lan969x_fan_write_pwm_period(fan);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "invalid fan PWM period\n");
+ }
+ lan969x_fan_enable(fan);
+
+ if (fan->cooling_levels) {
+ initial_pwm = fan->cooling_levels[fan->max_cooling_state];
+ ret = lan969x_fan_write_pwm(fan, initial_pwm);
+ if (ret)
+ return ret;
+ }
+
+ fan->hwmon_dev = devm_hwmon_device_register_with_info(dev, "lan969x_fan",
+ fan,
+ &lan969x_fan_chip_info,
+ NULL);
+ if (IS_ERR(fan->hwmon_dev))
+ return PTR_ERR(fan->hwmon_dev);
+
+ if (IS_ENABLED(CONFIG_THERMAL_OF) && fan->cooling_levels) {
+ cdev = devm_thermal_of_child_cooling_device_register(dev, fan_np,
+ "lan969x-fan", fan,
+ &lan969x_fan_cooling_ops);
+ if (IS_ERR(cdev))
+ return dev_err_probe(dev, PTR_ERR(cdev),
+ "failed to register cooling device\n");
+ }
+
+ return 0;
+}
+
+static const struct of_device_id lan969x_fan_match[] = {
+ { .compatible = "microchip,lan9691-fan" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, lan969x_fan_match);
+
+static struct platform_driver lan969x_fan_driver = {
+ .probe = lan969x_fan_probe,
+ .driver = {
+ .name = "lan969x-fan",
+ .of_match_table = lan969x_fan_match,
+ },
+};
+
+module_platform_driver(lan969x_fan_driver);
+
+MODULE_DESCRIPTION("Microchip LAN969x fan controller driver");
+MODULE_AUTHOR("Robert Marko <robert.marko@sartura.hr>");
+MODULE_LICENSE("GPL");
--
2.56.0
^ permalink raw reply related [flat|nested] 6+ messages in thread