Thread (30 messages) 30 messages, 4 authors, 2021-12-17

Re: [PATCH v4 20/20] extcon: intel-cht-wc: Report RID_A for ACA adapters

From: Chanwoo Choi <cw00.choi@samsung.com>
Date: 2021-12-16 02:32:42
Also in: linux-acpi, linux-efi, lkml, platform-driver-x86

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 <redacted>
---
 drivers/extcon/extcon-intel-cht-wc.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)
[snip]

Acked-by: Chanwoo Choi <cw00.choi@samsung.com>

-- 
Best Regards,
Chanwoo Choi
Samsung Electronics
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