[PATCH 1/3] dt-bindings: vendor-prefixes: Document Argon40

[PATCH 1/3] dt-bindings: vendor-prefixes: Document Argon40

[Marek Vasut]

Argon 40 Technologies Limited is a SBC expansion board vendor.
Document the prefix. For details see https://argon40.com .

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
---
 Documentation/devicetree/bindings/vendor-prefixes.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/vendor-prefixes.yaml b/Documentation/devicetree/bindings/vendor-prefixes.yaml
index 5d2a7a8d3ac6..e5e5bd34136a 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.yaml
+++ b/Documentation/devicetree/bindings/vendor-prefixes.yaml
@@ -149,6 +149,8 @@ patternProperties:
     description: Arctic Sand
   "^arcx,.*":
     description: arcx Inc. / Archronix Inc.
+  "^argon40,.*":
+    description: Argon 40 Technologies Limited
   "^ariaboard,.*":
     description: Shanghai Novotech Co., Ltd. (Ariaboard)
   "^aries,.*":
-- 
2.47.2

[PATCH 2/3] dt-bindings: trivial-devices: Document Argon40 Fan HAT

[Marek Vasut]

Document trivial PWM on Argon40 Fan HAT, which is a RaspberryPi
blower fan hat which can be controlled over I2C.

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
---
 Documentation/devicetree/bindings/trivial-devices.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
index 27930708ccd5..b8f1ee6e63dd 100644
--- a/Documentation/devicetree/bindings/trivial-devices.yaml
+++ b/Documentation/devicetree/bindings/trivial-devices.yaml
@@ -45,6 +45,8 @@ properties:
           - adi,lt7182s
             # AMS iAQ-Core VOC Sensor
           - ams,iaq-core
+            # Argon40 Fan HAT PWM controller
+          - argon40,fan-hat
             # Temperature monitoring of Astera Labs PT5161L PCIe retimer
           - asteralabs,pt5161l
             # i2c h/w elliptic curve crypto module
-- 
2.47.2

[PATCH 3/3] pwm: argon-fan-hat: Add Argon40 Fan HAT support

[Marek Vasut]

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
---
 drivers/pwm/Kconfig             |  9 +++++
 drivers/pwm/Makefile            |  1 +
 drivers/pwm/pwm-argon-fan-hat.c | 64 +++++++++++++++++++++++++++++++++
 3 files changed, 74 insertions(+)
 create mode 100644 drivers/pwm/pwm-argon-fan-hat.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index d9bcd1e8413e..02f1a52ea29e 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..3d04abdbd349
--- /dev/null
+++ b/drivers/pwm/pwm-argon-fan-hat.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025 Marek Vasut
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/pwm.h>
+
+static int argon_fan_hat_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+				   const struct pwm_state *state)
+{
+	struct i2c_client *i2c = pwmchip_get_drvdata(chip);
+	u8 tx[2] = { 0x80, state->enabled ? pwm_get_relative_duty_cycle(state, 100) : 0 };
+	struct i2c_msg msg = {
+		.addr = i2c->addr,
+		.len = 2,
+		.buf = tx,
+	};
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	return (i2c_transfer(i2c->adapter, &msg, 1) == 1) ? 0 : -EINVAL;
+}
+
+static const struct pwm_ops argon_fan_hat_pwm_ops = {
+	.apply = argon_fan_hat_pwm_apply,
+};
+
+static int argon_fan_hat_i2c_probe(struct i2c_client *i2c)
+{
+	struct pwm_chip *pc = devm_pwmchip_alloc(&i2c->dev, 1, 0);
+
+	if (IS_ERR(pc))
+		return PTR_ERR(pc);
+
+	pc->ops = &argon_fan_hat_pwm_ops;
+	pwmchip_set_drvdata(pc, i2c);
+
+	return devm_pwmchip_add(&i2c->dev, pc);
+}
+
+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

Re: [PATCH 3/3] pwm: argon-fan-hat: Add Argon40 Fan HAT support

[Uwe Kleine-König]

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Hello Marek,

I wonder how this device works in rpios, I didn't find a matching driver
(but I also didn't try more than two minutes).

On Wed, Jun 11, 2025 at 12:07:27AM +0200, Marek Vasut wrote:
> diff --git a/drivers/pwm/pwm-argon-fan-hat.c b/drivers/pwm/pwm-argon-fan-hat.c
> new file mode 100644
> index 000000000000..3d04abdbd349
> --- /dev/null
> +++ b/drivers/pwm/pwm-argon-fan-hat.c
> @@ -0,0 +1,64 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2025 Marek Vasut
> + */

 * Limitations:
 * - fixed period (which?)
 * - no support for offset/polarity

If you can find out if it completes a period when reconfigured that
would also be nice to document.

This device is really trivial, but for completeness' sake: If there is a
data sheet publicly available, please add a link here.

> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/pwm.h>
> +
> +static int argon_fan_hat_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> +				   const struct pwm_state *state)

Can you please implement the new-style callbacks?

> +{
> +	struct i2c_client *i2c = pwmchip_get_drvdata(chip);
> +	u8 tx[2] = { 0x80, state->enabled ? pwm_get_relative_duty_cycle(state, 100) : 0 };

This is too simple. I won't go into details about the right algorithm
for .apply() as I want you to implement .round_waveform_tohw() +
.round_waveform_fromhw() + .read_waveform() + .write_waveform() anyhow.

For .round_waveform_tohw() you have to know the actual period length and
then use something like:

	duty = wf->duty_length_ns;

	if (duty > ARGON_FAN_HAT_PERIOD)
		duty = ARGON_FAN_HAT_PERIOD;

	duty_percent = 100 * duty / ARGON_FAN_HAT_PERIOD;
	

> +	struct i2c_msg msg = {
> +		.addr = i2c->addr,
> +		.len = 2,
> +		.buf = tx,
> +	};
> +
> +	if (state->polarity != PWM_POLARITY_NORMAL)
> +		return -EINVAL;
> +
> +	return (i2c_transfer(i2c->adapter, &msg, 1) == 1) ? 0 : -EINVAL;
> +}
> +
> +static const struct pwm_ops argon_fan_hat_pwm_ops = {
> +	.apply = argon_fan_hat_pwm_apply,

Can you read back the configuration? If yes then please implement
.read_waveform().

> +};
> +
> +static int argon_fan_hat_i2c_probe(struct i2c_client *i2c)
> +{
> +	struct pwm_chip *pc = devm_pwmchip_alloc(&i2c->dev, 1, 0);
> +
> +	if (IS_ERR(pc))
> +		return PTR_ERR(pc);
> +
> +	pc->ops = &argon_fan_hat_pwm_ops;
> +	pwmchip_set_drvdata(pc, i2c);
> +
> +	return devm_pwmchip_add(&i2c->dev, pc);

Error message on failure please. (-> dev_err_probe())

> +}
> +
> +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,
> +};

TIL about PROBE_PREFER_ASYNCHRONOUS.

Best regards
Uwe

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Re: [PATCH 1/3] dt-bindings: vendor-prefixes: Document Argon40

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 313 bytes --]

On Wed, Jun 11, 2025 at 12:07:25AM +0200, Marek Vasut wrote:
> Argon 40 Technologies Limited is a SBC expansion board vendor.
> Document the prefix. For details see https://argon40.com .
> 
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

Acked-by: Conor Dooley <conor.dooley@microchip.com>

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Re: [PATCH 2/3] dt-bindings: trivial-devices: Document Argon40 Fan HAT

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 1533 bytes --]

On Wed, Jun 11, 2025 at 12:07:26AM +0200, Marek Vasut wrote:
> Document trivial PWM on Argon40 Fan HAT, which is a RaspberryPi
> blower fan hat which can be controlled over I2C.
> 
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

I don't see how a pwm controller, with a fan connected to it, is a
trivial device, sorry.
PWM fans have their own pwm consumer binding too, so it feels wrong on
two levels.

> ---
> 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
> ---
>  Documentation/devicetree/bindings/trivial-devices.yaml | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
> index 27930708ccd5..b8f1ee6e63dd 100644
> --- a/Documentation/devicetree/bindings/trivial-devices.yaml
> +++ b/Documentation/devicetree/bindings/trivial-devices.yaml
> @@ -45,6 +45,8 @@ properties:
>            - adi,lt7182s
>              # AMS iAQ-Core VOC Sensor
>            - ams,iaq-core
> +            # Argon40 Fan HAT PWM controller
> +          - argon40,fan-hat
>              # Temperature monitoring of Astera Labs PT5161L PCIe retimer
>            - asteralabs,pt5161l
>              # i2c h/w elliptic curve crypto module
> -- 
> 2.47.2
> 

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Re: [PATCH 3/3] pwm: argon-fan-hat: Add Argon40 Fan HAT support

[Marek Vasut]

On 6/11/25 7:55 AM, Uwe Kleine-König wrote:
> Hello Marek,

Hi,

> I wonder how this device works in rpios, I didn't find a matching driver
> (but I also didn't try more than two minutes).

The installation guide is here, download the PDF:

https://argon40.com/blogs/argon-resources/argon-fan-hat-installation-guide

Which leads to this script, which you download on the RPI and (better 
not without reading it first and understanding it) run:

https://download.argon40.com/argonfanhat.sh

Which downloads more scripts, installs systemd services which run other 
scripts, but ultimately this convoluted scripting leads to a single 
register write for this fan.

> On Wed, Jun 11, 2025 at 12:07:27AM +0200, Marek Vasut wrote:
>> diff --git a/drivers/pwm/pwm-argon-fan-hat.c b/drivers/pwm/pwm-argon-fan-hat.c
>> new file mode 100644
>> index 000000000000..3d04abdbd349
>> --- /dev/null
>> +++ b/drivers/pwm/pwm-argon-fan-hat.c
>> @@ -0,0 +1,64 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (C) 2025 Marek Vasut
>> + */
> 
>   * Limitations:
>   * - fixed period (which?)
>   * - no support for offset/polarity
> 
> If you can find out if it completes a period when reconfigured that
> would also be nice to document.
> 
> This device is really trivial, but for completeness' sake: If there is a
> data sheet publicly available, please add a link here.

There is nuvoton MS51FB9AE microcontroller on the underside of the 
board, which I think does the I2C communication and PWM generation. The 
firmware source does not seem available.

I can see some signal on the FAN itself, it is horribly noisy, but with 
sufficient filtering I can see they change the PWM period, from some 0 
Hz to 120 kHz , with duty cycle being some 10% (but I might be wrong, 
the signal is not great).

> 
>> +#include <linux/err.h>
>> +#include <linux/i2c.h>
>> +#include <linux/module.h>
>> +#include <linux/pwm.h>
>> +
>> +static int argon_fan_hat_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>> +				   const struct pwm_state *state)
> 
> Can you please implement the new-style callbacks?

Sure

[...]

>> +static const struct pwm_ops argon_fan_hat_pwm_ops = {
>> +	.apply = argon_fan_hat_pwm_apply,
> 
> Can you read back the configuration? If yes then please implement
> .read_waveform().

Nope, reading from the I2C device stops the fan.

Rest is fixed in V2, thanks.

-- 
Best regards,
Marek Vasut

Re: [PATCH 2/3] dt-bindings: trivial-devices: Document Argon40 Fan HAT

[Marek Vasut]

On 6/12/25 6:32 PM, Conor Dooley wrote:
> On Wed, Jun 11, 2025 at 12:07:26AM +0200, Marek Vasut wrote:
>> Document trivial PWM on Argon40 Fan HAT, which is a RaspberryPi
>> blower fan hat which can be controlled over I2C.
>>
>> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> 
> I don't see how a pwm controller, with a fan connected to it, is a
> trivial device, sorry.
> PWM fans have their own pwm consumer binding too, so it feels wrong on
> two levels.
Hopefully fixed in V2 series with dedicated bindings, thanks.