[lm-sensors] [PATCH 04/10] hwmon: (lm85) Don't write back cached values

Juerg Haefliger juergh at gmail.com
Wed May 28 02:52:42 CEST 2008


Looks good.

Acked-by: Juerg Haefliger <juergh at gmail.com>


On Sat, Apr 12, 2008 at 10:56 AM, Jean Delvare <khali at linux-fr.org> wrote:

> In set_pwm_auto_pwm_minctl, we write cached register bits back to the
> chip. This is a bad idea as we have no guarantee that the cache is
> up-to-date. Better read a fresh register value from the chip, it's
> safer and in fact it is also more simple.
>
> Signed-off-by: Jean Delvare <khali at linux-fr.org>
> ---
>  drivers/hwmon/lm85.c |   15 ++++++---------
>  1 file changed, 6 insertions(+), 9 deletions(-)
>
> --- linux-2.6.25-rc8.orig/drivers/hwmon/lm85.c  2008-04-03
> 09:50:16.000000000 +0200
> +++ linux-2.6.25-rc8/drivers/hwmon/lm85.c       2008-04-03
> 09:50:19.000000000 +0200
> @@ -309,10 +309,8 @@ struct lm85_data {
>        u8 pwm[3];              /* Register value */
>        u8 temp_ext[3];         /* Decoded values */
>        u8 in_ext[8];           /* Decoded values */
> -       u8 smooth[1];           /* Register encoding */
>        u8 vid;                 /* Register value */
>        u8 vrm;                 /* VRM version */
> -       u8 syncpwm3;            /* Saved PWM3 for TACH 2,3,4 config */
>        u32 alarms;             /* Register encoding, combined */
>        struct lm85_autofan autofan[3];
>        struct lm85_zone zone[3];
> @@ -757,14 +755,15 @@ static ssize_t set_pwm_auto_pwm_minctl(s
>        struct i2c_client *client = to_i2c_client(dev);
>        struct lm85_data *data = i2c_get_clientdata(client);
>        long val = simple_strtol(buf, NULL, 10);
> +       u8 tmp;
>
>        mutex_lock(&data->update_lock);
>        data->autofan[nr].min_off = val;
> -       lm85_write_value(client, LM85_REG_AFAN_SPIKE1, data->smooth[0]
> -               | data->syncpwm3
> -               | (data->autofan[0].min_off ? 0x20 : 0)
> -               | (data->autofan[1].min_off ? 0x40 : 0)
> -               | (data->autofan[2].min_off ? 0x80 : 0));
> +       tmp = lm85_read_value(client, LM85_REG_AFAN_SPIKE1);
> +       tmp &= ~(0x20 << nr);
> +       if (data->autofan[nr].min_off)
> +               tmp |= 0x20 << nr;
> +       lm85_write_value(client, LM85_REG_AFAN_SPIKE1, tmp);
>        mutex_unlock(&data->update_lock);
>        return count;
>  }
> @@ -1530,8 +1529,6 @@ static struct lm85_data *lm85_update_dev
>                }
>
>                i = lm85_read_value(client, LM85_REG_AFAN_SPIKE1);
> -               data->smooth[0] = i & 0x0f;
> -               data->syncpwm3 = i & 0x10;  /* Save PWM3 config */
>                data->autofan[0].min_off = (i & 0x20) != 0;
>                data->autofan[1].min_off = (i & 0x40) != 0;
>                data->autofan[2].min_off = (i & 0x80) != 0;
>
> --
> Jean Delvare
>
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