Commit 0f937c8d authored by XECDesign's avatar XECDesign Committed by Phil Elwell
Browse files

PoE HAT driver cleanup 



* Fix undeclared variable in rpi_poe_fan_suspend
* Add SPDX-License-Identifier
* Expand PoE acronym in Kconfig help
* Give clearer error message on of_property_count_u32_elems fail
* Add documentation
* Add vendor to of_device_id compatible string.
* Rename m_data_s struct to fw_data_s
* Fix typos

Fixes: #2665

Signed-off-by: default avatarSerge Schneider <serge@raspberrypi.org>
parent 55de35d3

Documentation/devicetree/bindings/hwmon/rpi-poe-fan.txt

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Bindings for the Raspberry Pi PoE HAT fan



Required properties:

- compatible	: "raspberrypi,rpi-poe-fan"

- firmware	: Reference to the RPi firmware device node

- pwms		: the PWM that is used to control the PWM fan

- cooling-levels      : PWM duty cycle values in a range from 0 to 255

			which correspond to thermal cooling states



Example:

	fan0: rpi-poe-fan@0 {

		compatible = "raspberrypi,rpi-poe-fan";

		firmware = <&firmware>;

		cooling-min-state = <0>;

		cooling-max-state = <3>;

		#cooling-cells = <2>;

		cooling-levels = <0 50 150 255>;

		status = "okay";

	};



	thermal-zones {

		cpu_thermal: cpu-thermal {

			trips {

				threshold: trip-point@0 {

					temperature = <45000>;

					hysteresis = <5000>;

					type = "active";

				};

				target: trip-point@1 {

					temperature = <50000>;

					hysteresis = <2000>;

					type = "active";

				};

				cpu_hot: cpu_hot@0 {

					temperature = <55000>;

					hysteresis = <2000>;

					type = "active";

				};

			};

			cooling-maps {

				map0 {

					trip = <&threshold>;

					cooling-device = <&fan0 0 1>;

				};

				map1 {

					trip = <&target>;

					cooling-device = <&fan0 1 2>;

				};

				map2 {

					trip = <&cpu_hot>;

					cooling-device = <&fan0 2 3>;

				};

			};

		};

	};

Documentation/hwmon/rpi-poe-fan

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Kernel driver rpi-poe-fan

=====================



This driver enables the use of the Raspberry Pi PoE HAT fan.



Author: Serge Schneider <serge@raspberrypi.org>



Description

-----------



The driver implements a simple interface for driving the Raspberry Pi PoE

(Power over Ethernet) HAT fan. The driver passes commands to the Raspberry Pi

firmware through the mailbox property interface. The firmware then forwards

the commands to the board over I2C on the ID_EEPROM pins. The driver exposes

the fan to the user space through the hwmon sysfs interface.

arch/arm/boot/dts/overlays/rpi-poe-overlay.dts

+1 −1
Original line number Diff line number Diff line
@@ -11,7 +11,7 @@ 
		target-path = "/";

		__overlay__ {

			fan0: rpi-poe-fan@0 {

				compatible = "rpi-poe-fan";

				compatible = "raspberrypi,rpi-poe-fan";

				firmware = <&firmware>;

				cooling-min-state = <0>;

				cooling-max-state = <3>;

drivers/hwmon/Kconfig

+3 −2
Original line number Diff line number Diff line
@@ -1287,11 +1287,12 @@ config SENSORS_PWM_FAN 
	  will be called pwm-fan.



config SENSORS_RPI_POE_FAN

	tristate "Raspberry Pi POE HAT fan"

	tristate "Raspberry Pi PoE HAT fan"

	depends on RASPBERRYPI_FIRMWARE

	depends on THERMAL || THERMAL=n

	help

	  If you say yes here you get support for Raspberry Pi POE HAT fan.

	  If you say yes here you get support for Raspberry Pi PoE (Power over

	  Ethernet) HAT fan.



	  This driver can also be built as a module.  If so, the module

	  will be called rpi-poe-fan.

drivers/hwmon/rpi-poe-fan.c

+16 −23
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * rpi-poe-fan.c - Hwmon driver for Raspberry Pi POE HAT fan.

 * rpi-poe-fan.c - Hwmon driver for Raspberry Pi PoE HAT fan.

 *

 * Copyright (C) 2018 Raspberry Pi (Trading) Ltd.

 * Based on pwm-fan.c by Kamil Debski <k.debski@samsung.com>

 *

 * Author: Serge Schneider <serge@raspberrypi.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/hwmon.h>
@@ -46,41 +37,41 @@ struct rpi_poe_fan_ctx { 
	struct notifier_block nb;

};



struct m_data_s{

struct fw_tag_data_s{

	u32 reg;

	u32 val;

	u32 ret;

};



static int write_reg(struct rpi_firmware *fw, u32 reg, u32 *val){

	struct m_data_s m_data = {

	struct fw_tag_data_s fw_tag_data = {

		.reg = reg,

		.val = *val

	};

	int ret;

	ret = rpi_firmware_property(fw, RPI_FIRMWARE_SET_POE_HAT_VAL,

				    &m_data, sizeof(m_data));

				    &fw_tag_data, sizeof(fw_tag_data));

	if (ret) {

		return ret;

	} else if (m_data.ret) {

	} else if (fw_tag_data.ret) {

		return -EIO;

	}

	return 0;

}



static int read_reg(struct rpi_firmware *fw, u32 reg, u32 *val){

	struct m_data_s m_data = {

	struct fw_tag_data_s fw_tag_data = {

		.reg = reg,

	};

	int ret;

	ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_POE_HAT_VAL,

				    &m_data, sizeof(m_data));

				    &fw_tag_data, sizeof(fw_tag_data));

	if (ret) {

		return ret;

	} else if (m_data.ret) {

	} else if (fw_tag_data.ret) {

		return -EIO;

	}

	*val = m_data.val;

	*val = fw_tag_data.val;

	return 0;

}
@@ -268,7 +259,8 @@ static int rpi_poe_fan_of_get_cooling_data(struct device *dev, 


	ret = of_property_count_u32_elems(np, "cooling-levels");

	if (ret <= 0) {

		dev_err(dev, "Wrong data!\n");

		dev_err(dev, "cooling-levels property missing or invalid: %d\n",

			ret);

		return ret ? : -EINVAL;

	}
@@ -397,10 +389,11 @@ static int rpi_poe_fan_suspend(struct device *dev) 
{

	struct rpi_poe_fan_ctx *ctx = dev_get_drvdata(dev);

	u32 value = 0;

	int ret = 0;



	if (ctx->pwm_value != value)

		ret = write_reg(ctx->fw, POE_CUR_PWM, &value);

	return 0;

	return ret;

}



static int rpi_poe_fan_resume(struct device *dev)
@@ -420,7 +413,7 @@ static SIMPLE_DEV_PM_OPS(rpi_poe_fan_pm, rpi_poe_fan_suspend, 
			 rpi_poe_fan_resume);



static const struct of_device_id of_rpi_poe_fan_match[] = {

	{ .compatible = "rpi-poe-fan", },

	{ .compatible = "raspberrypi,rpi-poe-fan", },

	{},

};

MODULE_DEVICE_TABLE(of, of_rpi_poe_fan_match);
@@ -439,5 +432,5 @@ module_platform_driver(rpi_poe_fan_driver); 


MODULE_AUTHOR("Serge Schneider <serge@raspberrypi.org>");

MODULE_ALIAS("platform:rpi-poe-fan");

MODULE_DESCRIPTION("Raspberry Pi POE HAT fan driver");

MODULE_DESCRIPTION("Raspberry Pi PoE HAT fan driver");

MODULE_LICENSE("GPL");