* [PATCH v5 2/3] dt-bindings: pwm: argon40,fan-hat: Document Argon40 Fan HAT
2025-06-29 22:07 [PATCH v5 1/3] dt-bindings: vendor-prefixes: Document Argon40 Marek Vasut
@ 2025-06-29 22:07 ` Marek Vasut
2025-06-29 22:07 ` [PATCH v5 3/3] pwm: argon-fan-hat: Add Argon40 Fan HAT support Marek Vasut
2025-06-30 8:12 ` [PATCH v5 1/3] dt-bindings: vendor-prefixes: Document Argon40 Uwe Kleine-König
2 siblings, 0 replies; 4+ messages in thread
From: Marek Vasut @ 2025-06-29 22:07 UTC (permalink / raw)
To: linux-pwm
Cc: Marek Vasut, Rob Herring (Arm), Uwe Kleine-König,
Conor Dooley, Krzysztof Kozlowski, devicetree, linux-renesas-soc
Document trivial PWM on Argon40 Fan HAT, which is a RaspberryPi
blower fan hat which can be controlled over I2C.
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: "Uwe Kleine-König" <ukleinek@kernel.org>
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: linux-pwm@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
---
V2: Implement dedicated binding document
V3: Update the description and pwm-cells
V4: Drop | from description and fix up pwm-cells = <2> in example
V5: Add RB from Rob
---
.../bindings/pwm/argon40,fan-hat.yaml | 48 +++++++++++++++++++
1 file changed, 48 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pwm/argon40,fan-hat.yaml
diff --git a/Documentation/devicetree/bindings/pwm/argon40,fan-hat.yaml b/Documentation/devicetree/bindings/pwm/argon40,fan-hat.yaml
new file mode 100644
index 000000000000..7dbc7c2cd802
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/argon40,fan-hat.yaml
@@ -0,0 +1,48 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/argon40,fan-hat.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Argon40 Fan HAT PWM controller
+
+maintainers:
+ - Marek Vasut <marek.vasut+renesas@mailbox.org>
+
+description:
+ The trivial PWM on Argon40 Fan HAT, which is a RaspberryPi blower fan
+ hat which can be controlled over I2C, generates a fixed 30 kHz period
+ PWM signal with configurable 0..100% duty cycle to control the fan
+ speed.
+
+allOf:
+ - $ref: pwm.yaml#
+
+properties:
+ compatible:
+ const: argon40,fan-hat
+
+ reg:
+ maxItems: 1
+
+ "#pwm-cells":
+ const: 3
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ pwm@1a {
+ compatible = "argon40,fan-hat";
+ reg = <0x1a>;
+ #pwm-cells = <3>;
+ };
+ };
--
2.47.2
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v5 3/3] pwm: argon-fan-hat: Add Argon40 Fan HAT support
2025-06-29 22:07 [PATCH v5 1/3] dt-bindings: vendor-prefixes: Document Argon40 Marek Vasut
2025-06-29 22:07 ` [PATCH v5 2/3] dt-bindings: pwm: argon40,fan-hat: Document Argon40 Fan HAT Marek Vasut
@ 2025-06-29 22:07 ` Marek Vasut
2025-06-30 8:12 ` [PATCH v5 1/3] dt-bindings: vendor-prefixes: Document Argon40 Uwe Kleine-König
2 siblings, 0 replies; 4+ messages in thread
From: Marek Vasut @ 2025-06-29 22:07 UTC (permalink / raw)
To: linux-pwm
Cc: Marek Vasut, Uwe Kleine-König, Conor Dooley,
Krzysztof Kozlowski, Rob Herring, devicetree, linux-renesas-soc
Add trivial PWM driver for Argon40 Fan HAT, which is a RaspberryPi
blower fan hat which can be controlled over I2C. Model this device
as a PWM, so the pwm-fan can be attached to it and handle thermal
zones and RPM management in a generic manner.
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: "Uwe Kleine-König" <ukleinek@kernel.org>
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: linux-pwm@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
---
V2: - Switch to waveform ops
- Add shutdown hook to force the fan to maximum RPM on shutdown
instead of stopping it, to be on the safe side
V3: - Find the 30 kHz fixed period PWM, use that
- Add comments
- Consolidate argon_fan_hat_write()
V4: - Add if (wf->duty_length_ns > ARGON40_FAN_HAT_PERIOD_NS) overflow check
- Use i2c_smbus_write_byte_data()
- Rename struct pwm_chip *pc to struct pwm_chip *chip
- Remove tab alignment from argon_fan_hat_pwm_ops {}
- Define ARGON40_FAN_HAT_REG_DUTY_CYCLE macro
V5: - Undo "Add shutdown hook" from V2
---
drivers/pwm/Kconfig | 9 +++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-argon-fan-hat.c | 109 ++++++++++++++++++++++++++++++++
3 files changed, 119 insertions(+)
create mode 100644 drivers/pwm/pwm-argon-fan-hat.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 6e113f8b4baf..3ef1757502eb 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -66,6 +66,15 @@ config PWM_APPLE
To compile this driver as a module, choose M here: the module
will be called pwm-apple.
+config PWM_ARGON_FAN_HAT
+ tristate "Argon40 Fan HAT support"
+ depends on I2C && OF
+ help
+ Generic PWM framework driver for Argon40 Fan HAT.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-argon-fan-hat.
+
config PWM_ATMEL
tristate "Atmel PWM support"
depends on ARCH_AT91 || COMPILE_TEST
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 96160f4257fc..ff4f47e5fb7a 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_PWM) += core.o
obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
obj-$(CONFIG_PWM_ADP5585) += pwm-adp5585.o
obj-$(CONFIG_PWM_APPLE) += pwm-apple.o
+obj-$(CONFIG_PWM_ARGON_FAN_HAT) += pwm-argon-fan-hat.o
obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o
obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM) += pwm-atmel-hlcdc.o
obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o
diff --git a/drivers/pwm/pwm-argon-fan-hat.c b/drivers/pwm/pwm-argon-fan-hat.c
new file mode 100644
index 000000000000..2c59bd142d40
--- /dev/null
+++ b/drivers/pwm/pwm-argon-fan-hat.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025 Marek Vasut
+ *
+ * Limitations:
+ * - no support for offset/polarity
+ * - fixed 30 kHz period
+ *
+ * Argon Fan HAT https://argon40.com/products/argon-fan-hat
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/pwm.h>
+
+#define ARGON40_FAN_HAT_PERIOD_NS 33333 /* ~30 kHz */
+
+#define ARGON40_FAN_HAT_REG_DUTY_CYCLE 0x80
+
+static int argon_fan_hat_round_waveform_tohw(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ const struct pwm_waveform *wf,
+ void *_wfhw)
+{
+ u8 *wfhw = _wfhw;
+
+ if (wf->duty_length_ns > ARGON40_FAN_HAT_PERIOD_NS)
+ *wfhw = 100;
+ else
+ *wfhw = mul_u64_u64_div_u64(wf->duty_length_ns, 100, ARGON40_FAN_HAT_PERIOD_NS);
+
+ return 0;
+}
+
+static int argon_fan_hat_round_waveform_fromhw(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ const void *_wfhw,
+ struct pwm_waveform *wf)
+{
+ const u8 *wfhw = _wfhw;
+
+ wf->period_length_ns = ARGON40_FAN_HAT_PERIOD_NS;
+ wf->duty_length_ns = DIV64_U64_ROUND_UP(wf->period_length_ns * *wfhw, 100);
+ wf->duty_offset_ns = 0;
+
+ return 0;
+}
+
+static int argon_fan_hat_write_waveform(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ const void *_wfhw)
+{
+ struct i2c_client *i2c = pwmchip_get_drvdata(chip);
+ const u8 *wfhw = _wfhw;
+
+ return i2c_smbus_write_byte_data(i2c, ARGON40_FAN_HAT_REG_DUTY_CYCLE, *wfhw);
+}
+
+static const struct pwm_ops argon_fan_hat_pwm_ops = {
+ .sizeof_wfhw = sizeof(u8),
+ .round_waveform_fromhw = argon_fan_hat_round_waveform_fromhw,
+ .round_waveform_tohw = argon_fan_hat_round_waveform_tohw,
+ .write_waveform = argon_fan_hat_write_waveform,
+ /*
+ * The controller does not provide any way to read info back,
+ * reading from the controller stops the fan, therefore there
+ * is no .read_waveform here.
+ */
+};
+
+static int argon_fan_hat_i2c_probe(struct i2c_client *i2c)
+{
+ struct pwm_chip *chip = devm_pwmchip_alloc(&i2c->dev, 1, 0);
+ int ret;
+
+ if (IS_ERR(chip))
+ return PTR_ERR(chip);
+
+ chip->ops = &argon_fan_hat_pwm_ops;
+ pwmchip_set_drvdata(chip, i2c);
+
+ ret = devm_pwmchip_add(&i2c->dev, chip);
+ if (ret)
+ return dev_err_probe(&i2c->dev, ret, "Could not add PWM chip\n");
+
+ return 0;
+}
+
+static const struct of_device_id argon_fan_hat_dt_ids[] = {
+ { .compatible = "argon40,fan-hat" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, argon_fan_hat_dt_ids);
+
+static struct i2c_driver argon_fan_hat_driver = {
+ .driver = {
+ .name = "argon-fan-hat",
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ .of_match_table = argon_fan_hat_dt_ids,
+ },
+ .probe = argon_fan_hat_i2c_probe,
+};
+
+module_i2c_driver(argon_fan_hat_driver);
+
+MODULE_AUTHOR("Marek Vasut <marek.vasut+renesas@mailbox.org>");
+MODULE_DESCRIPTION("Argon40 Fan HAT");
+MODULE_LICENSE("GPL");
--
2.47.2
^ permalink raw reply related [flat|nested] 4+ messages in thread