[lm-sensors] [PATCH v2 4/4] hwmon: (f75375s) Catch some attempts to write to r/o registers

[Guenter Roeck]

On Tue, Feb 28, 2012 at 04:15:54PM -0500, Nikolaus Schulz wrote:
> It makes no sense to attempt to manually configure the fan in auto mode,
> or set the duty cycle directly in closed loop mode.  The corresponding
> registers are then read-only.  If the user tries it nonetheless, error out
> with EINVAL instead of silently doing nothing.
> 
> Signed-off-by: Nikolaus Schulz <mail at microschulz.de>

Same as before - we can either hold the patch for 3.4, or split it into two parts.
Let me know which way you prefer.

Thanks,
Guenter

> ---
>  drivers/hwmon/f75375s.c |   27 +++++++++++++++++++++++++++
>  1 files changed, 27 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/hwmon/f75375s.c b/drivers/hwmon/f75375s.c
> index 3fee82dc..5374501 100644
> --- a/drivers/hwmon/f75375s.c
> +++ b/drivers/hwmon/f75375s.c
> @@ -278,6 +278,21 @@ static bool duty_mode_enabled(u8 pwm_enable)
>  	}
>  }
>  
> +static bool auto_mode_enabled(u8 pwm_enable)
> +{
> +	switch (pwm_enable) {
> +	case 0: /* Manual, duty mode (full speed) */
> +	case 1: /* Manual, duty mode */
> +	case 3: /* Manual, speed mode */
> +		return false;
> +	case 2: /* Auto, speed mode */
> +	case 4: /* Auto, duty mode */
> +		return true;
> +	default:
> +		BUG();
> +	}
> +}
> +
>  static ssize_t set_fan_min(struct device *dev, struct device_attribute *attr,
>  		const char *buf, size_t count)
>  {
> @@ -311,6 +326,11 @@ static ssize_t set_fan_target(struct device *dev, struct device_attribute *attr,
>  	if (err < 0)
>  		return err;
>  
> +	if (auto_mode_enabled(data->pwm_enable[nr]))
> +		return -EINVAL;
> +	if (data->kind == f75387 && duty_mode_enabled(data->pwm_enable[nr]))
> +		return -EINVAL;
> +
>  	mutex_lock(&data->update_lock);
>  	data->fan_target[nr] = rpm_to_reg(val);
>  	f75375_write16(client, F75375_REG_FAN_EXP(nr), data->fan_target[nr]);
> @@ -331,6 +351,10 @@ static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
>  	if (err < 0)
>  		return err;
>  
> +	if (auto_mode_enabled(data->pwm_enable[nr]) ||
> +			!duty_mode_enabled(data->pwm_enable[nr]))
> +		return -EINVAL;
> +
>  	mutex_lock(&data->update_lock);
>  	data->pwm[nr] = SENSORS_LIMIT(val, 0, 255);
>  	f75375_write_pwm(client, nr, data->pwm[nr]);
> @@ -792,6 +816,9 @@ static void f75375_init(struct i2c_client *client, struct f75375_data *data,
>  	set_pwm_enable_direct(client, 0, f75375s_pdata->pwm_enable[0]);
>  	set_pwm_enable_direct(client, 1, f75375s_pdata->pwm_enable[1]);
>  	for (nr = 0; nr < 2; nr++) {
> +		if (auto_mode_enabled(f75375s_pdata->pwm_enable[nr]) ||
> +		   !duty_mode_enabled(f75375s_pdata->pwm_enable[nr]))
> +			continue;
>  		data->pwm[nr] = SENSORS_LIMIT(f75375s_pdata->pwm[nr], 0, 255);
>  		f75375_write_pwm(client, nr, data->pwm[nr]);
>  	}
> -- 
> 1.7.9.1
>