| Message ID | 20211206093318.45214-21-hdegoede@redhat.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | power-suppy/i2c/extcon: Fix charger setup on Xiaomi Mi Pad 2 and Lenovo Yogabook | expand |
On 12/6/21 6:33 PM, Hans de Goede wrote: > 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. > > Signed-off-by: Hans de Goede <hdegoede@redhat.com> > --- > drivers/extcon/extcon-intel-cht-wc.c | 18 +++++++++++++----- > 1 file changed, 13 insertions(+), 5 deletions(-) [snip] Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
diff --git a/drivers/extcon/extcon-intel-cht-wc.c b/drivers/extcon/extcon-intel-cht-wc.c index 144cb5d8cd47..2a8d41cbf41c 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; } }
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. Signed-off-by: Hans de Goede <hdegoede@redhat.com> --- drivers/extcon/extcon-intel-cht-wc.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)