Hi,
On Fri, Sep 18, 2015 at 04:39:53PM -0500, 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 502dd8a5..135cfd4 100644
> --- a/drivers/power/bq24257_charger.c
> +++ b/drivers/power/bq24257_charger.c
> @@ -107,6 +107,7 @@ struct bq24257_device {
> struct mutex lock; /* protect state data */
>
> bool iilimit_autoset_enable;
> + bool pg_gpio_disable;
I don't think this is required.
> };
>
> static bool bq24257_is_volatile_reg(struct device *dev, unsigned int reg)
> @@ -360,7 +361,26 @@ 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);
I guess you can just handle this like an optional gpio
if(bq->pg)
state->power_good = !gpiod_get_value_cansleep(bq->pg);
else
...
>
> return 0;
> }
> @@ -680,7 +700,7 @@ 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");
> return PTR_ERR(bq->pg);
> }
>
> @@ -814,10 +834,27 @@ static int bq24257_probe(struct i2c_client *client,
> INIT_DELAYED_WORK(&bq->iilimit_setup_work,
> bq24257_iilimit_setup_work);
>
> - /* we can only check Power Good status by probing the PG pin */
> - ret = bq24257_pg_gpio_probe(bq);
> - if (ret < 0)
> - return ret;
> + /*
> + * The BQ24250 doesn't have a dedicated Power Good (PG) pin so we
> + * explicitly disable this feature for this device and instead use
> + * a SW-based approach to determine the PG state.
> + */
> + if (bq->chip == BQ24250)
> + bq->pg_gpio_disable = true;
> +
> + /*
> + * For devices that do have a dedicated PG pin go ahead and probe it,
> + * using the SW-based approach as a fall back solution. Note that the
> + * use of the dedicated pin is preferred.
> + */
> + if (!bq->pg_gpio_disable) {
> + ret = bq24257_pg_gpio_probe(bq);
> + if (ret < 0) {
> + dev_info(bq->dev,
> + "using SW-based power-good detection\n");
> + bq->pg_gpio_disable = true;
> + }
> + }
>
> /* reset all registers to defaults */
> ret = bq24257_field_write(bq, F_RESET, 1);
-- Sebastian
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