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List:       lm-sensors
Subject:    Re: [lm-sensors] [PATCH 1/6] hwmon: (f75375s) Fix register write order when setting fans to full spe
From:       Nikolaus Schulz <mail () microschulz ! de>
Date:       2012-02-23 1:46:40
Message-ID: 20120223014640.GA7948 () luigi ! zusammrottung ! local
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On Wed, Feb 22, 2012 at 05:14:22PM -0800, Guenter Roeck wrote:
> On Wed, Feb 22, 2012 at 05:18:44PM -0500, Nikolaus Schulz wrote:
> > From: Nikolaus Schulz <schulz@macnetix.de>
> > 
> > By hwmon sysfs interface convention, setting pwm_enable to zero sets a fan
> > to full speed.  In the f75375s driver, this need be done by enabling
> > manual fan control, plus duty mode for the F875387 chip, and then setting
> > the maximum duty cycle.  Fix a bug where the two necessary register writes
> > were swapped, effectively discarding the setting to full-speed.
> > 
> > Signed-off-by: Nikolaus Schulz <mail@microschulz.de>
> > ---
> >  drivers/hwmon/f75375s.c |    7 +++----
> >  1 files changed, 3 insertions(+), 4 deletions(-)
> > 
> Nikolaus,
> 
> this patch modifies register write order for the other chips as well.
> Does that have any impact on the other chips ? Or, in other words,
> is this patch also necessary for stable ?

I think so, although I have tested it only on the F75387.

(For stable kernels it needs to be backported.)

Nikolaus

> > diff --git a/drivers/hwmon/f75375s.c b/drivers/hwmon/f75375s.c
> > index faf66c8..5dae122 100644
> > --- a/drivers/hwmon/f75375s.c
> > +++ b/drivers/hwmon/f75375s.c
> > @@ -340,8 +340,6 @@ static int set_pwm_enable_direct(struct i2c_client *client, int nr, int val)
> >  			fanmode |= (1 << F75387_FAN_MANU_MODE(nr));
> >  			fanmode |= (1 << F75387_FAN_DUTY_MODE(nr));
> >  			data->pwm[nr] = 255;
> > -			f75375_write8(client, F75375_REG_FAN_PWM_DUTY(nr),
> > -					data->pwm[nr]);
> >  			break;
> >  		case 1: /* PWM */
> >  			fanmode  |= (1 << F75387_FAN_MANU_MODE(nr));
> > @@ -361,8 +359,6 @@ static int set_pwm_enable_direct(struct i2c_client *client, int nr, int val)
> >  		case 0: /* full speed */
> >  			fanmode  |= (3 << FAN_CTRL_MODE(nr));
> >  			data->pwm[nr] = 255;
> > -			f75375_write8(client, F75375_REG_FAN_PWM_DUTY(nr),
> > -					data->pwm[nr]);
> >  			break;
> >  		case 1: /* PWM */
> >  			fanmode  |= (3 << FAN_CTRL_MODE(nr));
> > @@ -377,6 +373,9 @@ static int set_pwm_enable_direct(struct i2c_client *client, int nr, int val)
> >  
> >  	f75375_write8(client, F75375_REG_FAN_TIMER, fanmode);
> >  	data->pwm_enable[nr] = val;
> > +	if (val == 0)
> > +		f75375_write8(client, F75375_REG_FAN_PWM_DUTY(nr),
> > +				data->pwm[nr]);
> >  	return 0;
> >  }
> >  
> > -- 
> > 1.7.9.1
> > 
> 

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