Re: [PATCH v2 3/9] usb: misc: qcom_eud: add per-path High-Speed PHY control
From: Konrad Dybcio <hidden>
Date: 2026-02-04 13:21:57
Also in:
linux-arm-msm, linux-usb, lkml
On 1/27/26 12:38 AM, Elson Serrao wrote:
EUD hardware can support multiple High-Speed USB paths, each routed through its own PHY. The active path is selected in hardware via the EUD_PORT_SEL register. As a High-Speed hub, EUD requires access to the High-Speed PHY associated with the active UTMI path. To support this multi-path capability, the driver must manage PHY resources on a per-path basis, ensuring that the PHY for the currently selected path is properly initialized and powered. This patch restructures the driver to implement per-path PHY management. The driver now powers the appropriate PHY based on the selected and enabled UTMI path, ensuring correct operation when EUD is enabled. Supporting this requires describing the available UTMI paths and their corresponding PHYs in Device Tree. This updates DT requirements and is not backward compatible with older DTs that lacked this description. Historically, EUD appeared to work on single-path systems because the USB controller kept the PHY initialized. However, EUD is designed to operate independently of the USB controller and therefore requires explicit PHY control. Signed-off-by: Elson Serrao <redacted> ---
[...]
+static int eud_phy_enable(struct eud_chip *chip)
+{
+ struct eud_path *path;
+ struct phy *phy;
+ int ret;
+
+ if (chip->phy_enabled)
+ return 0;
+
+ path = chip->paths[chip->port_idx];
+ if (!path || !path->phy) {I think neither are possible - path is != NULL since we can't enter into this function without failing the check in _store and !path->phy would error out in probe()->eud_init_path() [...]
+static void eud_phy_disable(struct eud_chip *chip)
+{
+ struct eud_path *path;
+ struct phy *phy;
+
+ if (!chip->phy_enabled)
+ return;
+
+ path = chip->paths[chip->port_idx];
+ if (!path || !path->phy)Likewise [...]
+static int eud_init_path(struct eud_chip *chip, struct device_node *np)
+{
+ struct eud_path *path;
+ u32 path_num;
+ int ret;
+
+ ret = of_property_read_u32(np, "reg", &path_num);
+ if (ret) {
+ dev_err(chip->dev, "Missing 'reg' property in path node\n");
+ return ret;You can use return dev_err_probe like you did a little below
quoted hunk ↗ jump to hunk
+ } + + if (path_num >= EUD_MAX_PORTS) { + dev_err(chip->dev, "Invalid path number: %u (max %d)\n", + path_num, EUD_MAX_PORTS - 1); + return -EINVAL; + } + + path = devm_kzalloc(chip->dev, sizeof(*path), GFP_KERNEL); + if (!path) + return -ENOMEM; + + path->chip = chip; + path->num = path_num; + + path->phy = devm_of_phy_get(chip->dev, np, NULL); + if (IS_ERR(path->phy)) + return dev_err_probe(chip->dev, PTR_ERR(path->phy), + "Failed to get PHY for path %d\n", path_num); + + chip->paths[path_num] = path; + + return 0; +} + static int eud_probe(struct platform_device *pdev) { + struct device_node *np = pdev->dev.of_node; + struct device_node *child; struct eud_chip *chip; struct resource *res; int ret;@@ -252,6 +368,18 @@ static int eud_probe(struct platform_device *pdev) if (ret) return ret; + for_each_child_of_node(np, child) {
With for_each_child_of_node_scoped(), you can dispose of the manual _put()
+ ret = eud_init_path(chip, child);
+ if (ret) {
+ of_node_put(child);
+ return ret;
+ }
+ }
+
+ /* Primary path is mandatory. Secondary is optional */
+ if (!chip->paths[0])
+ return -ENODEV;I'm going to assume we don't have any funny chips that violate this :) Konrad