Hi Guenter

On 06/24/2016 10:10 AM, Guenter Roeck wrote:

Hi Chris,

On Thu, Jun 23, 2016 at 5:34 PM, Chris Zhong [off-list ref] wrote:

quoted

Hi Guenter


On 06/24/2016 05:47 AM, Guenter Roeck wrote:

quoted

Hi Chris,

On Thu, Jun 23, 2016 at 5:51 AM, Chris Zhong [off-list ref] wrote:

quoted

Add a PHY provider driver for the rk3399 SoC Type-c PHY. The USB
Type-C PHY is designed to support the USB3 and DP applications. The
PHY basically has two main components: USB3 and DisplyPort. USB3
operates in SuperSpeed mode and the DP can operate at RBR, HBR and
HBR2 data rates.

Signed-off-by: Chris Zhong <redacted>
Signed-off-by: Kever Yang <redacted>

[ ... ]

quoted

+
+static void tcphy_get_state(struct rockchip_typec_phy *tcphy,
+                           struct extcon_dev *edev)
+{
+       int mode;
+       bool plugged, flip, pin_assign, dfp, ufp, dp;
+
+       ufp = extcon_get_cable_state_(edev, EXTCON_USB);
+       dfp = extcon_get_cable_state_(edev, EXTCON_USB_HOST);
+       dp = extcon_get_cable_state_(edev, EXTCON_DISP_DP);
+       flip = extcon_get_cable_state_(edev, EXTCON_TYPEC_POLARITY);
+       pin_assign = extcon_get_cable_state_(edev,
EXTCON_TYPEC_PIN_ASSIGN);
+
+       plugged = ufp | dfp | dp;
+       tcphy->flip = flip;
+
+       if (plugged) {
+               if (ufp) {
+                       mode = MODE_UFP_USB;
+               } else if (dfp && !dp) {
+                       mode = MODE_DFP_USB;
+               } else if (dfp && dp) {
+                       mode = MODE_DFP_USB | MODE_DFP_DP;
+                       tcphy->pin_assign = pin_assign ? PIN_MAP_D :
PIN_MAP_B;
+               } else {
+                       mode = MODE_DFP_DP;
+                       tcphy->pin_assign = pin_assign ? PIN_MAP_C :
PIN_MAP_A;

I am having trouble extracting pin_assign from our code. What
determines if map A or C should be selected ?

Thanks,
Guenter

Oh, forgot rename the macro:

PIN_MAP_ should be PIN_ASSIGN_


  IF EXTCON_TYPEC_PIN_ASSIGN is attached, Type-C get
  Pin_Assignment_C(for DP only mode) or Pin_Assignment_D(for DP alt mode),
   if detached, it get the default Assignment: A(for DP only mode) or B(for
DP alt mode),.

So we are really talking about DP only vs. DP Alt mode ? If so, do we
even need PIN_ASSIGN ? Why not just use EXTCON_DISP_DP_ALT directly ?

Also, I'll have to get a better understanding what "DP only mode" and
"DP Alt mode" actually means. DisplayPort is already a Type-C
alternate mode, so the terminology is a bit confusing. Do you happen
to have a description somewhere, by any chance ?

Thanks,
Guenter

The Pin Assignments is come from:
VESA DisplayPort Alt Mode on USB Type-C Standard

There are 2 mode for DP: DP only mode, and DP+USB3 mode(EXTCON_DISP_DP_ALT )
At DP only mode, DP has 4 lanes of Type-C;
At DP+USB3 mode, DP has 2 lanes, and USB3 has the other 2 lanes.

For DP only mode, there are 3 kind of pin assignments: A, C, E.
For DP + USB3 mode, there are 3 kind of pin assignments: B, D, F.

Pin Assignments C and D use the same assignments as Pin Assignments E and F.
Thence, we just need to distinguish A and C for DP only mode.
and distinguish B and D for DP + USB3 mode.
That why the phy need a PIN_ASSIGN cable.


The name of "DP Alt mode", it is DP+USB3 mode, actually.
I think if the name makes anyone confused, it can be changed to DP_USB3 mode:
The cable list could be:
EXTCON_DISP_DP
EXTCON_DISP_DP_USB3

quoted

I am going to add a comment for describe which PIN_ASSIGN_ should be
selected
in next version, if no one disagrees the usage of cable

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