On Tue, Feb 28, 2012 at 04:15:53PM -0500, Nikolaus Schulz wrote:
> From: Nikolaus Schulz <schulz@xxxxxxxxxxx>
>
> The F75387 supports automatic fan control using either PWM duty cycle or
> RPM speed values. Make the driver detect the latter mode, and expose the
> different modes in sysfs as per pwm_enable, so that the user can switch
> between them.
>
> The interpretation of the pwm_enable attribute for the F75387 is adjusted
> to be a superset of those values used for similar Fintek chips which do
> not support automatic duty mode, with 2 mapping to automatic speed mode,
> and moving automatic duty mode to the new value 4.
>
> Toggling the duty mode via pwm_enable is currently denied for the F75387,
> as the chip then simply reinterprets the fan configuration register values
> according to the new mode, switching between RPM and PWM units, which
> makes this a dangerous operation.
>
> Signed-off-by: Nikolaus Schulz <mail@xxxxxxxxxxxxxx>
Nikolaus,
I don't feel comfortable adding this patch to 3.3 at this point; it is not a pure
bug fix but a functionality enhancement. We can either wait for 3.4, or split it into
two patches (if possible), one to fix <automatic, speed mode> for 3.3 and one to add
<automatic, pwm> for 3.4.
Any preference ?
Thanks,
Guenter
> ---
> drivers/hwmon/f75375s.c | 42 ++++++++++++++++++++++++++++++++++--------
> 1 files changed, 34 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/hwmon/f75375s.c b/drivers/hwmon/f75375s.c
> index 29c0d06..3fee82dc 100644
> --- a/drivers/hwmon/f75375s.c
> +++ b/drivers/hwmon/f75375s.c
> @@ -263,6 +263,21 @@ static inline u16 rpm_to_reg(int rpm)
> return 1500000 / rpm;
> }
>
> +static bool duty_mode_enabled(u8 pwm_enable)
> +{
> + switch (pwm_enable) {
> + case 0: /* Manual, duty mode (full speed) */
> + case 1: /* Manual, duty mode */
> + case 4: /* Auto, duty mode */
> + return true;
> + case 2: /* Auto, speed mode */
> + case 3: /* Manual, speed mode */
> + return false;
> + default:
> + BUG();
> + }
> +}
> +
> static ssize_t set_fan_min(struct device *dev, struct device_attribute *attr,
> const char *buf, size_t count)
> {
> @@ -336,11 +351,15 @@ static int set_pwm_enable_direct(struct i2c_client *client, int nr, int val)
> struct f75375_data *data = i2c_get_clientdata(client);
> u8 fanmode;
>
> - if (val < 0 || val > 3)
> + if (val < 0 || val > 4)
> return -EINVAL;
>
> fanmode = f75375_read8(client, F75375_REG_FAN_TIMER);
> if (data->kind == f75387) {
> + /* For now, deny dangerous toggling of duty mode */
> + if (duty_mode_enabled(data->pwm_enable[nr]) !=
> + duty_mode_enabled(val))
> + return -EOPNOTSUPP;
> /* clear each fanX_mode bit before setting them properly */
> fanmode &= ~(1 << F75387_FAN_DUTY_MODE(nr));
> fanmode &= ~(1 << F75387_FAN_MANU_MODE(nr));
> @@ -354,12 +373,14 @@ 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));
> break;
> - case 2: /* AUTOMATIC*/
> - fanmode |= (1 << F75387_FAN_DUTY_MODE(nr));
> + case 2: /* Automatic, speed mode */
> break;
> case 3: /* fan speed */
> fanmode |= (1 << F75387_FAN_MANU_MODE(nr));
> break;
> + case 4: /* Automatic, pwm */
> + fanmode |= (1 << F75387_FAN_DUTY_MODE(nr));
> + break;
> }
> } else {
> /* clear each fanX_mode bit before setting them properly */
> @@ -377,6 +398,8 @@ static int set_pwm_enable_direct(struct i2c_client *client, int nr, int val)
> break;
> case 3: /* fan speed */
> break;
> + case 4: /* Automatic pwm */
> + return -EINVAL;
> }
> }
>
> @@ -734,14 +757,17 @@ static void f75375_init(struct i2c_client *client, struct f75375_data *data,
>
> manu = ((mode >> F75387_FAN_MANU_MODE(nr)) & 1);
> duty = ((mode >> F75387_FAN_DUTY_MODE(nr)) & 1);
> - if (manu && duty)
> - /* speed */
> + if (!manu && duty)
> + /* auto, pwm */
> + data->pwm_enable[nr] = 4;
> + else if (manu && !duty)
> + /* manual, speed */
> data->pwm_enable[nr] = 3;
> - else if (!manu && duty)
> - /* automatic */
> + else if (!manu && !duty)
> + /* automatic, speed */
> data->pwm_enable[nr] = 2;
> else
> - /* manual */
> + /* manual, pwm */
> data->pwm_enable[nr] = 1;
> } else {
> if (!(conf & (1 << F75375_FAN_CTRL_LINEAR(nr))))
> --
> 1.7.9.1
>
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