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Patch "hwmon: (it87) Do not overwrite bit 2..6 of pwm control registers" has been added to the 4.10-stable tree

PATCH [email protected] 1 participant 1 message Mar 8, 2017

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This is a note to let you know that I've just added the patch titled

hwmon: (it87) Do not overwrite bit 2..6 of pwm control registers

to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     hwmon-it87-do-not-overwrite-bit-2..6-of-pwm-control-registers.patch

and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 4c7b8ca1ae5ed9e27014732c8a918ba11a86cf09 Mon Sep 17 00:00:00 2001

From: Guenter Roeck <[email protected]>
Date: Wed, 8 Feb 2017 14:07:42 -0800
Subject: hwmon: (it87) Do not overwrite bit 2..6 of pwm control registers

From: Guenter Roeck <[email protected]>

commit 4c7b8ca1ae5ed9e27014732c8a918ba11a86cf09 upstream.

In IT8620E, after setting pwm control to manual, it was observed that pwm values for fan 4..6 have reversed results (writing 0 results in fans running at full speed, writing 255 results in fans turned off).

With the new PWM control, pwm polarity for pwm control 4..6 is specified in its pwm control registers. Those registers are overwritten when setting the pwm mode or the temperature mapping. Do not touch bit 2..6 of pwm control registers on register writes to fix the problem.

---
 drivers/hwmon/it87.c |   37 ++++++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 13 deletions(-)
drivers/hwmon/it87.c +24 -13
@@ -1300,25 +1300,35 @@ static ssize_t set_pwm_enable(struct dev
 			it87_write_value(data, IT87_REG_FAN_MAIN_CTRL,
 					 data->fan_main_ctrl);
 		} else {
+			u8 ctrl;
+
 			/* No on/off mode, set maximum pwm value */
 			data->pwm_duty[nr] = pwm_to_reg(data, 0xff);
 			it87_write_value(data, IT87_REG_PWM_DUTY[nr],
 					 data->pwm_duty[nr]);
 			/* and set manual mode */
-			data->pwm_ctrl[nr] = has_newer_autopwm(data) ?
-					     data->pwm_temp_map[nr] :
-					     data->pwm_duty[nr];
-			it87_write_value(data, IT87_REG_PWM[nr],
-					 data->pwm_ctrl[nr]);
+			if (has_newer_autopwm(data)) {
+				ctrl = (data->pwm_ctrl[nr] & 0x7c) |
+					data->pwm_temp_map[nr];
+			} else {
+				ctrl = data->pwm_duty[nr];
+			}
+			data->pwm_ctrl[nr] = ctrl;
+			it87_write_value(data, IT87_REG_PWM[nr], ctrl);
 		}
 	} else {
-		if (val == 1)				/* Manual mode */
-			data->pwm_ctrl[nr] = has_newer_autopwm(data) ?
-					     data->pwm_temp_map[nr] :
-					     data->pwm_duty[nr];
-		else					/* Automatic mode */
-			data->pwm_ctrl[nr] = 0x80 | data->pwm_temp_map[nr];
-		it87_write_value(data, IT87_REG_PWM[nr], data->pwm_ctrl[nr]);
+		u8 ctrl;
+
+		if (has_newer_autopwm(data)) {
+			ctrl = (data->pwm_ctrl[nr] & 0x7c) |
+				data->pwm_temp_map[nr];
+			if (val != 1)
+				ctrl |= 0x80;
+		} else {
+			ctrl = (val == 1 ? data->pwm_duty[nr] : 0x80);
+		}
+		data->pwm_ctrl[nr] = ctrl;
+		it87_write_value(data, IT87_REG_PWM[nr], ctrl);
 
 		if (data->type != it8603 && nr < 3) {
 			/* set SmartGuardian mode */
@@ -1462,7 +1472,8 @@ static ssize_t set_pwm_temp_map(struct d
 	 * otherwise, just store it for later use.
 	 */
 	if (data->pwm_ctrl[nr] & 0x80) {
-		data->pwm_ctrl[nr] = 0x80 | data->pwm_temp_map[nr];
+		data->pwm_ctrl[nr] = (data->pwm_ctrl[nr] & 0xfc) |
+						data->pwm_temp_map[nr];
 		it87_write_value(data, IT87_REG_PWM[nr], data->pwm_ctrl[nr]);
 	}
 	mutex_unlock(&data->update_lock);

Patches currently in stable-queue which might be from [email protected] are

queue-4.10/hwmon-it87-ensure-that-pwm-control-cache-is-current-before-updating-values.patch queue-4.10/hwmon-it87-do-not-overwrite-bit-2..6-of-pwm-control-registers.patch