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    SubjectRe: [PATCH 3/3] power/ds2760_battery: use factor of 20 for rated_capacity
    On Tue, May 11, 2010 at 06:38:46PM +0200, Daniel Mack wrote:
    > In the ds2760 driver, the currently used factor of 10 to store the rated
    > battery capacity internally is not sufficient for batteries > 2.55 Ah,
    > as the 8-bit register will overflow for bigger values.
    >
    > Change the factor to 20 to broaden that range. Note that due to
    > RATED_CAPACITY_FACTOR, the external interface won't change, neither for
    > the writeable sysfs entires nor for the kernel rated_capacity module
    > parameter.
    >
    > Signed-off-by: Daniel Mack <daniel@caiaq.de>
    > Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
    > Cc: Matt Reimer <mreimer@vpop.net>
    > Cc: Evgeniy Polyakov <zbr@ioremap.net>
    > Cc: Tejun Heo <tj@kernel.org>
    > Cc: David Woodhouse <dwmw2@infradead.org>
    > Cc: Len Brown <len.brown@intel.com>
    > Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
    > ---

    Hi Daniel,

    Sorry, it took quite a bit to get to your patches.

    They look good (as usual), but I have a few concerns.

    > drivers/power/ds2760_battery.c | 2 +-
    > 1 files changed, 1 insertions(+), 1 deletions(-)
    >
    > diff --git a/drivers/power/ds2760_battery.c b/drivers/power/ds2760_battery.c
    > index b82bf92..7b3043f 100644
    > --- a/drivers/power/ds2760_battery.c
    > +++ b/drivers/power/ds2760_battery.c
    > @@ -78,7 +78,7 @@ MODULE_PARM_DESC(current_accum, "current accumulator value");
    >
    > /* Some batteries have their rated capacity stored a N * 10 mAh, while
    > * others use an index into this table. */
    > -#define RATED_CAPACITY_FACTOR 10
    > +#define RATED_CAPACITY_FACTOR 20

    I'm a bit worried about this one.

    Shouldn't this confuse batteries that already store rated
    capacity with factor of ten? If so, please introduce a module
    option.

    Also, you don't update comments and module params description,
    e.g.

    MODULE_PARM_DESC(rated_capacity, "rated battery capacity, 10*mAh or index");
    ....
    /* set rated capacity from module param (given in 10 * mAh) */
    Is that intentionally?

    Thanks!

    --
    Anton Vorontsov
    email: cbouatmailru@gmail.com
    irc://irc.freenode.net/bd2


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