[PATCH 1/2] leds-lm3530: comment correction about the range of brightness

[PATCH 1/2] leds-lm3530: comment correction about the range of brightness

[Kim, Milo]

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

Re: [PATCH 1/2] leds-lm3530: comment correction about the range of brightness

[Linus Walleij]

On Thu, Apr 19, 2012 at 8:40 AM, Kim, Milo <Milo.Kim@ti.com> wrote:

> 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>

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

RE: [PATCH 1/2] leds-lm3530: comment correction about the range of brightness

[Shreshtha Kumar SAHU]

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

RE: [PATCH 1/2] leds-lm3530: comment correction about the range of brightness

[Kim, Milo]

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
> 

RE: [PATCH 1/2] leds-lm3530: comment correction about the range of brightness

[Shreshtha Kumar SAHU]

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
>