diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2022-02-01 14:07:06 +0100 |
|---|---|---|
| committer | Sebastian Reichel <sebastian.reichel@collabora.com> | 2022-02-01 14:55:12 +0100 |
| commit | 21356ac14e054ee86a34008e2c59bd3f1b42d7bf (patch) | |
| tree | 7d02c2839c09dfacf3fcca557d5cbc46a11e0b3a | |
| parent | 66e31186cd2aa7ee325b64555321e2ba06f141ab (diff) | |
| download | linux-next-21356ac14e054ee86a34008e2c59bd3f1b42d7bf.tar.gz | |
extcon: intel-cht-wc: Report RID_A for ACA adapters
Make cht_wc_extcon_get_id() report RID_A for ACA adapters, instead of
reporting ID_FLOAT.
According to the spec. we should read the USB-ID pin ADC value
to determine the resistance of the used pull-down resister and
then return RID_A / RID_B / RID_C based on this. But all "Accessory
Charger Adapter"s (ACAs) which users can actually buy always use
a combination of a charging port with one or more USB-A ports, so
they should always use a resistor indicating RID_A. But the spec
is hard to read / badly-worded so some of them actually indicate
they are a RID_B ACA even though they clearly are a RID_A ACA.
To workaround this simply always return INTEL_USB_RID_A, which
matches all the ACAs which users can actually buy.
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
| -rw-r--r-- | drivers/extcon/extcon-intel-cht-wc.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/drivers/extcon/extcon-intel-cht-wc.c b/drivers/extcon/extcon-intel-cht-wc.c index cf74acb92fe3..89a6449e3f4a 100644 --- a/drivers/extcon/extcon-intel-cht-wc.c +++ b/drivers/extcon/extcon-intel-cht-wc.c @@ -121,13 +121,21 @@ static int cht_wc_extcon_get_id(struct cht_wc_extcon_data *ext, int pwrsrc_sts) return INTEL_USB_ID_GND; case CHT_WC_PWRSRC_RID_FLOAT: return INTEL_USB_ID_FLOAT; + /* + * According to the spec. we should read the USB-ID pin ADC value here + * to determine the resistance of the used pull-down resister and then + * return RID_A / RID_B / RID_C based on this. But all "Accessory + * Charger Adapter"s (ACAs) which users can actually buy always use + * a combination of a charging port with one or more USB-A ports, so + * they should always use a resistor indicating RID_A. But the spec + * is hard to read / badly-worded so some of them actually indicate + * they are a RID_B ACA evnen though they clearly are a RID_A ACA. + * To workaround this simply always return INTEL_USB_RID_A, which + * matches all the ACAs which users can actually buy. + */ case CHT_WC_PWRSRC_RID_ACA: + return INTEL_USB_RID_A; default: - /* - * Once we have IIO support for the GPADC we should read - * the USBID GPADC channel here and determine ACA role - * based on that. - */ return INTEL_USB_ID_FLOAT; } } |