Messages in this thread | | | Date | Wed, 19 Dec 2007 13:02:41 -0500 | From | Andres Salomon <> | Subject | Re: [PATCH 1/5] power: RFC: introduce a new power API |
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On Wed, 19 Dec 2007 15:35:46 +0300 Anton Vorontsov <cbou@mail.ru> wrote:
> On Tue, Dec 18, 2007 at 02:10:01AM -0500, Andres Salomon wrote: > > On Mon, 17 Dec 2007 14:24:16 +0300 > > Anton Vorontsov <cbou@mail.ru> wrote: > > > > > On Mon, Dec 17, 2007 at 02:41:39AM -0500, Andres Salomon wrote: > > > [...] > > > > > > On Sun, 2007-12-16 at 21:24 -0500, Andres Salomon wrote: > > > > > > > This API has the power_supply drivers device their own device_attribute > > > > > > > list; I find this to be a lot more flexible and cleaner. > > > > > > > > > > I don't see how this is more flexible and cleaner. See below. > > > > > > > > > > > > For example, > > > > > > > rather than having a function with a huge switch statement (as olpc_battery > > > > > > > currently has), we have separate callback functions. > > > > > > > > > > Is this an improvement? Look into ds2760_battery.c. I scared to > > > > > imagine what it will look like after conversion. > > > > > > [...] > > > > > > I see your point now. Basically, now I'm encourage to think just one > > > more time: is there third (better) option in addition to current and > > > this? I still hope there is some not obvious, but elegant solution. > > > If there isn't, I'm ready to surrender and will help with everything > > > I can. > > > > > > > Hm. It occurs to me that there's nothing keeping us from having a > > single callback for the driver properties. Keeping the other patches > > the same, do you prefer the following approach versus what was originally > > in patch#3? > > Why so difficult? Maybe like this: >
The point is to get rid of 'propval', and having the core driver define formats. That's one of the places where we ran into problems with the current API; by having the core driver define what type a property should be returning, we limit battery drivers to what they can display, as well as encourage a lot of non-shared code to end up in the core driver. That's the reason why we strcpy into 'buf', rather than val->strval.
For transitioning, we could certainly just use val->strval all of the time, but there's not much point in doing that in the long term; we might as well just pass around 'buf'.
> diff --git a/drivers/power/olpc_battery.c b/drivers/power/olpc_battery.c > index c998e68..00f0b71 100644 > --- a/drivers/power/olpc_battery.c > +++ b/drivers/power/olpc_battery.c > @@ -176,13 +176,13 @@ static int olpc_bat_get_property(struct power_supply *psy, > > switch (ec_byte >> 4) { > case 1: > - val->strval = "Gold Peak"; > + ret = sprintf(val->strval, "%s\n", "Gold Peak"); > break; > case 2: > - val->strval = "BYD"; > + ret = sprintf(val->strval, "%s\n", "BYD"); > break; > default: > - val->strval = "Unknown"; > + ret = sprintf(val->strval, "%s\n", "Unknown"); > break; > } > break; > diff --git a/drivers/power/power_supply_sysfs.c b/drivers/power/power_supply_sysfs.c > index 249f61b..83e127d 100644 > --- a/drivers/power/power_supply_sysfs.c > +++ b/drivers/power/power_supply_sysfs.c > @@ -54,7 +54,9 @@ static ssize_t power_supply_show_property(struct device *dev, > ssize_t ret; > struct power_supply *psy = dev_get_drvdata(dev); > const ptrdiff_t off = attr - power_supply_attrs; > - union power_supply_propval value; > + union power_supply_propval value = { > + .strval = buf, > + }; > > ret = psy->get_property(psy, off, &value); > > @@ -75,7 +77,7 @@ static ssize_t power_supply_show_property(struct device *dev, > return sprintf(buf, "%s\n", > capacity_level_text[value.intval]); > else if (off >= POWER_SUPPLY_PROP_MODEL_NAME) > - return sprintf(buf, "%s\n", value.strval); > + return ret; > > return sprintf(buf, "%d\n", value.intval); > }
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