Chunfeng Yun wrote:
> On Fri, 2020-07-24 at 16:39 -0700, Thinh Nguyen wrote:
>> Add a new common function to parse maximum_speed property string for
>> the specified number of lanes and transfer rate.
>>
>> Signed-off-by: Thinh Nguyen <thinhn@xxxxxxxxxxxx>
>> ---
>> Changes in v3:
>> - Add new function to parse "maximum-speed" for lanes and transfer rate
>> - Remove separate functions getting num_lanes and transfer rate properties
>> Changes in v2:
>> - New commit
>>
>> drivers/usb/common/common.c | 47 ++++++++++++++++++++++++++++++++++++++++++---
>> include/linux/usb/ch9.h | 25 ++++++++++++++++++++++++
>> 2 files changed, 69 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/usb/common/common.c b/drivers/usb/common/common.c
>> index 1433260d99b4..53b4950c49e4 100644
>> --- a/drivers/usb/common/common.c
>> +++ b/drivers/usb/common/common.c
>> @@ -77,18 +77,59 @@ const char *usb_speed_string(enum usb_device_speed speed)
>> }
>> EXPORT_SYMBOL_GPL(usb_speed_string);
>>
>> -enum usb_device_speed usb_get_maximum_speed(struct device *dev)
>> +void usb_get_maximum_speed_and_num_lanes(struct device *dev,
>> + enum usb_device_speed *speed,
>> + enum usb_phy_gen *gen,
>> + u8 *num_lanes)
>> {
>> const char *maximum_speed;
>> + enum usb_device_speed matched_speed = USB_SPEED_UNKNOWN;
>> + enum usb_phy_gen matched_gen = USB_PHY_GEN_UNKNOWN;
>> + u8 matched_num_lanes = 0;
>> int ret;
>>
>> ret = device_property_read_string(dev, "maximum-speed", &maximum_speed);
>> if (ret < 0)
>> - return USB_SPEED_UNKNOWN;
>> + goto done;
>>
>> ret = match_string(speed_names, ARRAY_SIZE(speed_names), maximum_speed);
>> + if (ret >= 0) {
>> + matched_speed = ret;
>> + goto done;
>> + }
>> +
>> + if (strncmp("super-speed-plus-gen2x2", maximum_speed, 23) == 0) {
>> + matched_speed = USB_SPEED_SUPER_PLUS;
>> + matched_gen = USB_PHY_GEN_2;
>> + matched_num_lanes = 2;
>> + } else if (strncmp("super-speed-plus-gen2x1", maximum_speed, 23) == 0) {
>> + matched_speed = USB_SPEED_SUPER_PLUS;
>> + matched_gen = USB_PHY_GEN_2;
>> + matched_num_lanes = 1;
>> + } else if (strncmp("super-speed-plus-gen1x2", maximum_speed, 23) == 0) {
>> + matched_speed = USB_SPEED_SUPER_PLUS;
>> + matched_gen = USB_PHY_GEN_1;
>> + matched_num_lanes = 2;
>> + }
>> +
>> +done:
>> + if (speed)
>> + *speed = matched_speed;
>> +
>> + if (num_lanes)
>> + *num_lanes = matched_num_lanes;
>> +
>> + if (gen)
>> + *gen = matched_gen;
>> +}
>> +EXPORT_SYMBOL_GPL(usb_get_maximum_speed_and_num_lanes);
>> +
>> +enum usb_device_speed usb_get_maximum_speed(struct device *dev)
>> +{
>> + enum usb_device_speed speed;
>>
>> - return (ret < 0) ? USB_SPEED_UNKNOWN : ret;
>> + usb_get_maximum_speed_and_num_lanes(dev, &speed, NULL, NULL);
>> + return speed;
>> }
>> EXPORT_SYMBOL_GPL(usb_get_maximum_speed);
>>
>> diff --git a/include/linux/usb/ch9.h b/include/linux/usb/ch9.h
>> index 01191649a0ad..46cfd72e7082 100644
>> --- a/include/linux/usb/ch9.h
>> +++ b/include/linux/usb/ch9.h
>> @@ -57,6 +57,13 @@ enum usb_link_protocol {
>> USB_LP_SSP = 1,
>> };
>>
>> +/* USB phy signaling rate gen */
>> +enum usb_phy_gen {
>> + USB_PHY_GEN_UNKNOWN,
>> + USB_PHY_GEN_1,
>> + USB_PHY_GEN_2,
>> +};
> The GEN_1, GEN_2 will describe the capability of not only PHY but also
> MAC, add _PHY_ seems a little ambiguous, I think
> usb_get_maximum_speed_and_num_lanes() is mainly used to get the
> capability of MAC. Another, not suitable to add property about PHY
> capablity in MAC nodes.
>
From USB 3.2 spec:
"Gen 1 is an adjective used to refer to the Physical layer associated
with a 5.0 Gbps signaling rate. The original USB SuperSpeed Phy and a
Gen 1 Phy refer to the same Phy."
"Gen 2 is an adjective used to refer to the Physical layer associated
with a 10 Gbps signaling rate."
If you have a better name, I'm open for suggestions.
BR,
Thinh
