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    SubjectRE: [PATCH 1/2] leds-lm3530: comment correction about the range of brightness
    IMHO it should be hidden inside driver. For example if hardware supports >8 bits for 
    brightness then too we scale/map 0-255 to supported range in hardware.

    BR
    Shreshtha

    -----Original Message-----
    From: Kim, Milo [mailto:Milo.Kim@ti.com]
    Sent: Friday, April 20, 2012 2:14 PM
    To: Shreshtha Kumar SAHU
    Cc: linus.walleij@linaro.org; Richard Purdie; linux-kernel@vger.kernel.org; Andrew Morton
    Subject: RE: [PATCH 1/2] leds-lm3530: comment correction about the range of brightness


    In the previous patch, max brightness was limited to 127 because only 7 bits are used in the brightness register.

    http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commit;h=bbe6453204c568723679212f6d0653b92b3d6244

    With this patch, 128 ~ 255 is invalid range of brightness, so comment needs to be corrected.
    (Even if the brt_val is greater than 127, the brightness will be set as max_brightness - 127)

    Thanks & BR
    Milo -

    > -----Original Message-----
    > From: Shreshtha Kumar SAHU [mailto:shreshthakumar.sahu@stericsson.com]
    > Sent: Friday, April 20, 2012 4:29 PM
    > To: Kim, Milo
    > Cc: linus.walleij@linaro.org; Richard Purdie; linux-
    > kernel@vger.kernel.org; Andrew Morton
    > Subject: RE: [PATCH 1/2] leds-lm3530: comment correction about the
    > range of brightness
    >
    > I feel driver should take care of range provided by hardware by
    > scaling the value provided by user, instead of limiting the max
    > brightness to user.
    >
    > For .e.g. here it can be something like this -
    > err = i2c_smbus_write_byte_data(drvdata->client,
    > LM3530_BRT_CTRL_REG, brt_val / 2);
    >
    > I am not sure if application really use/check max brightness in before
    > calculating/setting new brightness values.
    >
    > -----Original Message-----
    > From: Kim, Milo [mailto:Milo.Kim@ti.com]
    > Sent: Thursday, April 19, 2012 12:11 PM
    > To: Andrew Morton
    > Cc: Shreshtha Kumar SAHU; linus.walleij@linaro.org; Richard Purdie;
    > linux-kernel@vger.kernel.org
    > Subject: [PATCH 1/2] leds-lm3530: comment correction about the range of
    > brightness
    >
    > max brightness is 127, so the range of brt_val should be from 0 to 127
    >
    > Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
    > ---
    > include/linux/led-lm3530.h | 2 +-
    > 1 files changed, 1 insertions(+), 1 deletions(-)
    >
    > diff --git a/include/linux/led-lm3530.h b/include/linux/led-lm3530.h
    > index eeae6e7..4b13347 100644
    > --- a/include/linux/led-lm3530.h
    > +++ b/include/linux/led-lm3530.h
    > @@ -92,7 +92,7 @@ struct lm3530_pwm_data {
    > * @als2_resistor_sel: internal resistance from ALS2 input to ground
    > * @als_vmin: als input voltage calibrated for max brightness in mV
    > * @als_vmax: als input voltage calibrated for min brightness in mV
    > - * @brt_val: brightness value (0-255)
    > + * @brt_val: brightness value (0-127)
    > * @pwm_data: PWM control functions (only valid when the mode is PWM)
    > */
    > struct lm3530_platform_data {
    > --
    > 1.7.4.1
    >
    >
    > Best Regards,
    > Milo (Woogyom) Kim
    >



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