Re: [PATCH] TSL2550: extended mode bugfix

[Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>]

Hi Michele,

On Wed, 05 Aug 2009 17:08:05 +0200, Michele De Candia (VT) wrote:
> Hi all,
> according to the TAOS Application Note 'Controlling a Backlight with the
> TSL2550 Ambient Light Sensor' (page 14), the actual lux value in
> extended mode should be obtained multiplying the calculated lux value by 5.
> The following patch should fix the lux calculation in this case.
> 
> Regards,
> Michele De Candia
> --
> 
> Signed-off-by: Michele Jr De Candia <michele.decandia-EZxuzQJkuwwybS5Ee8rs3A@public.gmane.org>
> 
> drivers/i2c/chips/tsl2550.c |    7 +++++--
> 1 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/i2c/chips/tsl2550.c b/drivers/i2c/chips/tsl2550.c
> index b96f302..04b87e0 100644
> --- a/drivers/i2c/chips/tsl2550.c
> +++ b/drivers/i2c/chips/tsl2550.c
> @@ -279,7 +279,7 @@ static ssize_t __tsl2550_show_lux(struct i2c_client
> *client, char *buf)
> {
>      u8 ch0, ch1;

I don't know what your e-mail client is doing to the source code, but
it's bad. It replaces tabs with spaces and folds long lines at least -
I won't be able to apply your patch. Please either fix your client, or
attach the patch instead of inlining it.

>      int ret;
> -
> +    struct tsl2550_data *data = i2c_get_clientdata(client);
>      ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC0);
>      if (ret < 0)
>          return ret;
> @@ -293,7 +293,10 @@ static ssize_t __tsl2550_show_lux(struct i2c_client
> *client, char *buf)
>      ch1 = ret;
> 
>      /* Do the job */
> -    ret = tsl2550_calculate_lux(ch0, ch1);
> +    if (!data->operating_mode)
> +        ret = tsl2550_calculate_lux(ch0, ch1);
> +    else
> +        ret = tsl2550_calculate_lux(ch0, ch1) * 5;
>      if (ret < 0)
>          return ret;

Operating on values before you check for errors is wrong. I'd rather do:

    ret = tsl2550_calculate_lux(ch0, ch1);
    if (ret < 0)
        return ret;
    if (data->operating_mode == 1) /* extended mode */
        ret *= 5;

OK?

-- 
Jean Delvare