Re: [PATCH 3/4] extcon: arizona: Update manual headphone detection calculation

From: Chanwoo Choi
Date: Thu May 29 2014 - 21:27:41 EST


Hi Charles,

On 05/30/2014 12:27 AM, Charles Keepax wrote:
> The higher levels of impedance have a higher minimum value than the
> first level. As the same value was used for all levels, higher impedances
> were reported with a very low level of accuracy. This patch applies the
> approriate lower threshold for each level.
>
> Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/extcon/extcon-arizona.c | 13 ++++++++-----
> 1 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/extcon/extcon-arizona.c b/drivers/extcon/extcon-arizona.c
> index f2c36b1..c1c8647 100644
> --- a/drivers/extcon/extcon-arizona.c
> +++ b/drivers/extcon/extcon-arizona.c
> @@ -329,12 +329,13 @@ static void arizona_stop_mic(struct arizona_extcon_info *info)
> }
>
> static struct {
> + unsigned int threshold;
> unsigned int factor_a;
> unsigned int factor_b;
> } arizona_hpdet_b_ranges[] = {
> - { 5528, 362464 },
> - { 11084, 6186851 },
> - { 11065, 65460395 },
> + { 100, 5528, 362464 },
> + { 169, 11084, 6186851 },
> + { 169, 11065, 65460395 },

If you possible, I want to know the 'unit' of the variable(factor_a, factor_b).

> };
>
> static struct {
> @@ -391,7 +392,8 @@ static int arizona_hpdet_read(struct arizona_extcon_info *info)
> >> ARIZONA_HP_IMPEDANCE_RANGE_SHIFT;
>
> if (range < ARRAY_SIZE(arizona_hpdet_b_ranges) - 1 &&
> - (val < 100 || val >= 0x3fb)) {
> + (val < arizona_hpdet_b_ranges[range].threshold ||
> + val >= 0x3fb)) {

I don't understand the meaning of 0x3fb hex value.
I prefer to define constant variable for readability.

> range++;
> dev_dbg(arizona->dev, "Moving to HPDET range %d\n",
> range);
> @@ -404,7 +406,8 @@ static int arizona_hpdet_read(struct arizona_extcon_info *info)
> }
>
> /* If we go out of range report top of range */
> - if (val < 100 || val >= 0x3fb) {
> + if (val < arizona_hpdet_b_ranges[range].threshold ||
> + val >= 0x3fb) {

ditto.

> dev_dbg(arizona->dev, "Measurement out of range\n");
> return ARIZONA_HPDET_MAX;
> }
>

Thanks,
Chanwoo Choi

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/