Re: [PATCH] power_supply: Add driver for TWL4030/TPS65950 BCI charger

[Grazvydas Ignotas <notasas@gmail.com>]

On Wed, Dec 2, 2009 at 11:27 PM, Anton Vorontsov
<avorontsov@ru.mvista.com> wrote:
> On Wed, Dec 02, 2009 at 10:38:31PM +0200, Grazvydas Ignotas wrote:
>> On Mon, Nov 30, 2009 at 8:58 PM, Anton Vorontsov
>> <avorontsov@ru.mvista.com> wrote:
>> > On Mon, Nov 30, 2009 at 12:45:20PM -0600, Madhusudhan wrote:
>> > [...]
>> >> > +   case POWER_SUPPLY_PROP_VOLTAGE_NOW:
>> >> > +           /* charging must be active for meaningful result */
>> >> > +           if (!is_charging) {
>> >>
>> >> How about putting a kern_info here?
>> >
>> > It might be better to return -EINVAL.
>>
>> That causes lots of warnings from power_supply core (driver failed to
>> report XXX property), Not sure what to do here, I'd prefer to keep
>> returning 0.
>
> Lying to userspace is a bad idea.
>
> How about this patch + changing the driver to return -ENODATA?

This is fine for me, thanks.

>
> From 0fe4c834b551c4d4454d57acaf75645675d199ee Mon Sep 17 00:00:00 2001
> From: Anton Vorontsov <avorontsov@ru.mvista.com>
> Date: Thu, 3 Dec 2009 00:24:51 +0300
> Subject: [PATCH] power_supply_sysfs: Handle -ENODATA in a special way
>
> There are cases when some device can not report any meaningful value,
> e.g. TWL4030 charger can report voltage only when charging is
> active.
>
> In these cases drivers will return -ENODATA, and we shouldn't flood
> kernel log with error messages.
>
> Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
> ---
>  drivers/power/power_supply_sysfs.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/power/power_supply_sysfs.c b/drivers/power/power_supply_sysfs.c
> index 0814439..c790e0c 100644
> --- a/drivers/power/power_supply_sysfs.c
> +++ b/drivers/power/power_supply_sysfs.c
> @@ -65,7 +65,10 @@ static ssize_t power_supply_show_property(struct device *dev,
>        ret = psy->get_property(psy, off, &value);
>
>        if (ret < 0) {
> -               if (ret != -ENODEV)
> +               if (ret == -ENODATA)
> +                       dev_dbg(dev, "driver has no data for `%s' property\n",
> +                               attr->attr.name);
> +               else if (ret != -ENODEV)
>                        dev_err(dev, "driver failed to report `%s' property\n",
>                                attr->attr.name);
>                return ret;
> --
> 1.6.3.3
>
>