On 16.09.2015 02:58, Andreas Dannenberg wrote:
> A software-based approach for determining the charger's input voltage
> "Power Good" state is introduced for devices like the bq24250 which
> don't have a dedicated hardware pin for that purpose. This SW-based
> approach is also used for other devices (with dedicated PG pin) as a
> fall back solution if that pin is not configured to be used through
> "pg-gpios".
>
> Signed-off-by: Andreas Dannenberg <dannenberg@xxxxxx>
> ---
> drivers/power/bq24257_charger.c | 49 ++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 43 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/power/bq24257_charger.c b/drivers/power/bq24257_charger.c
> index 55e4ee4..d7488cf 100644
> --- a/drivers/power/bq24257_charger.c
> +++ b/drivers/power/bq24257_charger.c
> @@ -103,6 +103,7 @@ struct bq24257_device {
> struct mutex lock; /* protect state data */
>
> bool in_ilimit_autoset_disable;
> + bool pg_gpio_disable;
> };
>
> static bool bq24257_is_volatile_reg(struct device *dev, unsigned int reg)
> @@ -356,7 +357,26 @@ static int bq24257_get_chip_state(struct bq24257_device *bq,
>
> state->fault = ret;
>
> - state->power_good = !gpiod_get_value_cansleep(bq->pg);
> + if (bq->pg_gpio_disable)
> + /*
> + * If we have a chip without a dedicated power-good GPIO or
> + * some other explicit bit that would provide this information
> + * assume the power is good if there is no supply related
> + * fault - and not good otherwise. There is a possibility for
> + * other errors to mask that power in fact is not good but this
> + * is probably the best we can do here.
> + */
> + switch (state->fault) {
> + case FAULT_INPUT_OVP:
> + case FAULT_INPUT_UVLO:
> + case FAULT_INPUT_LDO_LOW:
> + state->power_good = false;
> + break;
> + default:
> + state->power_good = true;
> + }
> + else
> + state->power_good = !gpiod_get_value_cansleep(bq->pg);
>
> return 0;
> }
> @@ -676,7 +696,7 @@ static int bq24257_pg_gpio_probe(struct bq24257_device *bq)
> {
> bq->pg = devm_gpiod_get_index(bq->dev, BQ24257_PG_GPIO, 0, GPIOD_IN);
> if (IS_ERR(bq->pg)) {
> - dev_err(bq->dev, "could not probe PG pin\n");
> + dev_info(bq->dev, "could not probe PG pin\n");
I think if pg-gpio is provided (e.g. by DTS) but it is invalid (return
value != ENOENT) then it is an error you could print. The driver will
fallback to the software method but still user/developer may want to
notice the error (e.g. error in DTS).
Anyway it is up to you, rest looks good:
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
Best regards,
Krzysztof
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