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authorHans de Goede <hdegoede@redhat.com>2022-02-01 16:07:06 +0300
committerSebastian Reichel <sebastian.reichel@collabora.com>2022-02-01 16:55:12 +0300
commit21356ac14e054ee86a34008e2c59bd3f1b42d7bf (patch)
tree7d02c2839c09dfacf3fcca557d5cbc46a11e0b3a /drivers/extcon
parent66e31186cd2aa7ee325b64555321e2ba06f141ab (diff)
downloadlinux-21356ac14e054ee86a34008e2c59bd3f1b42d7bf.tar.xz
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>
Diffstat (limited to 'drivers/extcon')
-rw-r--r--drivers/extcon/extcon-intel-cht-wc.c18
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;
}
}