linux-kernel - [PATCH v5 10/13] platform/x86: oxpec: Adhere to sysfs-class-hwmon and enable pwm on 2

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Message-ID: <20250317155349.1236188-11-lkml@antheas.dev>
Date: Mon, 17 Mar 2025 16:53:46 +0100
From: Antheas Kapenekakis <lkml@...heas.dev>
To: platform-driver-x86@...r.kernel.org
Cc: linux-hwmon@...r.kernel.org,
	linux-doc@...r.kernel.org,
	linux-pm@...r.kernel.org,
	Guenter Roeck <linux@...ck-us.net>,
	Jean Delvare <jdelvare@...e.com>,
	Jonathan Corbet <corbet@....net>,
	Joaquin Ignacio Aramendia <samsagax@...il.com>,
	Derek J Clark <derekjohn.clark@...il.com>,
	Kevin Greenberg <kdgreenberg234@...tonmail.com>,
	Joshua Tam <csinaction@...me>,
	Parth Menon <parthasarathymenon@...il.com>,
	Eileen <eileen@...-netbook.com>,
	linux-kernel@...r.kernel.org,
	sre@...nel.org,
	linux@...ssschuh.net,
	Antheas Kapenekakis <lkml@...heas.dev>
Subject: [PATCH v5 10/13] platform/x86: oxpec: Adhere to sysfs-class-hwmon and
 enable pwm on 2

Currently, the driver does not adhere to the sysfs-class-hwmon
specification: 0 is used for auto fan control and 1 is used for manual
control. However, it is expected that 0 sets the fan to full speed,
1 sets the fan to manual, and then 2 is used for automatic control.

Therefore, change the sysfs API to reflect this and enable pwm on 2.

As we are breaking the ABI for this driver, rename oxpec to oxp_ec,
reflecting the naming convention used by other drivers, to allow for
a smooth migration in current userspace programs.

Closes: https://lore.kernel.org/linux-hwmon/20241027174836.8588-1-derekjohn.clark@gmail.com/
Reviewed-by: Derek J. Clark <derekjohn.clark@...il.com>
Signed-off-by: Antheas Kapenekakis <lkml@...heas.dev>
---
 drivers/platform/x86/oxpec.c | 35 ++++++++++++++++++++++++++++++++---
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/oxpec.c b/drivers/platform/x86/oxpec.c
index 61b070168249e..14fa70652087b 100644
--- a/drivers/platform/x86/oxpec.c
+++ b/drivers/platform/x86/oxpec.c
@@ -731,7 +731,27 @@ static int oxp_platform_read(struct device *dev, enum hwmon_sensor_types type,
 		case hwmon_pwm_input:
 			return oxp_pwm_input_read(val);
 		case hwmon_pwm_enable:
-			return oxp_pwm_read(val);
+			ret = oxp_pwm_read(val);
+			if (ret)
+				return ret;
+
+			/* Check for auto and return 2 */
+			if (!*val) {
+				*val = 2;
+				return 0;
+			}
+
+			/* Return 0 if at full fan speed, 1 otherwise */
+			ret = oxp_pwm_fan_speed(val);
+			if (ret)
+				return ret;
+
+			if (*val == 255)
+				*val = 0;
+			else
+				*val = 1;
+
+			return 0;
 		default:
 			break;
 		}
@@ -745,15 +765,24 @@ static int oxp_platform_read(struct device *dev, enum hwmon_sensor_types type,
 static int oxp_platform_write(struct device *dev, enum hwmon_sensor_types type,
 			      u32 attr, int channel, long val)
 {
+	int ret;
+
 	switch (type) {
 	case hwmon_pwm:
 		switch (attr) {
 		case hwmon_pwm_enable:
 			if (val == 1)
 				return oxp_pwm_enable();
-			else if (val == 0)
+			else if (val == 2)
 				return oxp_pwm_disable();
-			return -EINVAL;
+			else if (val != 0)
+				return -EINVAL;
+
+			/* Enable PWM and set to max speed */
+			ret = oxp_pwm_enable();
+			if (ret)
+				return ret;
+			return oxp_pwm_input_write(255);
 		case hwmon_pwm_input:
 			return oxp_pwm_input_write(val);
 		default:
-- 
2.48.1