usb: uhci: Add clk support to uhci-platform

Quoted 59 lines · Benjamin Herrenschmidt

The Aspeed SoCs use uhci-platform. With the new dynamic clock control framework, the corresponding IP block clock must be properly enabled.

This is a simplified variant of what ehci-platform does, it looks for *one* clock attached to the device, and if it's there, enables it.

Signed-off-by Benjamin Herrenschmidt <[email protected]>

---

v3. Fix tab vs. spaces and probe error path

v2. Don't forget to git add latest changes :-) This adds the
part where we turn the clock off when removing the driver.

 drivers/usb/host/uhci-hcd.h      |  3 +++
 drivers/usb/host/uhci-platform.c | 24 ++++++++++++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

drivers/usb/host/uhci-hcd.h +3 -0

index f1cc47292a59..7f9f33c8c232 100644
@@ -4,6 +4,7 @@
 
 #include <linux/list.h>
 #include <linux/usb.h>
+#include <linux/clk.h>
 
 #define usb_packetid(pipe)   (usb_pipein(pipe) ? USB_PID_IN : USB_PID_OUT)
 #define PIPE_DEVEP_MASK              0x0007ff00

@@ -447,6 +448,8 @@ struct uhci_hcd {
      int total_load;                         /* Sum of array values */
      short load[MAX_PHASE];                  /* Periodic allocations */
 
+     struct clk *clk;                        /* (optional) clock source */
+
      /* Reset host controller */
      void    (*reset_hc) (struct uhci_hcd *uhci);
      int     (*check_and_reset_hc) (struct uhci_hcd *uhci);

drivers/usb/host/uhci-platform.c +2 -0

index 6cb16d4b2257..0d86ad244922 100644
@@ -89,6 +89,8 @@ static int uhci_hcd_platform_probe(struct platform_device *pdev)
      if (!hcd)
              return -ENOMEM;
 
+     uhci = hcd_to_uhci(hcd);
+
      res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
      hcd->regs = devm_ioremap_resource(&pdev->dev, res);
      if (IS_ERR(hcd->regs)) {

@@ -98,8 +100,6 @@ static int uhci_hcd_platform_probe(struct platform_device *pdev)
      hcd->rsrc_start = res->start;
      hcd->rsrc_len = resource_size(res);
 

drivers/usb/host/uhci-platform.c static int uhci_hcd_platform_probe(struct platform_device *pdev) · line 102

Quoted 2 lines

drivers/usb/host/uhci-platform.c +0 -2

-     uhci = hcd_to_uhci(hcd);
-

Any particular reason for moving this line up?

Quoted 29 lines

drivers/usb/host/uhci-platform.c +15 -0

      uhci->regs = hcd->regs;
 
      /* Grab some things from the device-tree */

@@ -119,6 +119,21 @@ static int uhci_hcd_platform_probe(struct platform_device *pdev)
                               "Enabled Aspeed implementation workarounds\n");
              }
      }
+
+     /* Get and enable clock if any specified */
+     uhci->clk = devm_clk_get(&pdev->dev, NULL);
+     if (IS_ERR(uhci->clk)) {
+             ret = PTR_ERR(uhci->clk);
+             goto err_rmr;
+     }
+     if (uhci->clk) {
+             ret = clk_prepare_enable(uhci->clk);
+             if (ret) {
+                     dev_err(&pdev->dev, "Error couldn't enable clock (%d)\n", ret);
+                     goto err_rmr;
+             }
+     }
+
      ret = usb_add_hcd(hcd, pdev->resource[1].start, IRQF_SHARED);
      if (ret)
              goto err_rmr;

@@ -127,6 +142,8 @@ static int uhci_hcd_platform_probe(struct platform_device *pdev)
      return 0;
 

drivers/usb/host/uhci-platform.c static int uhci_hcd_platform_probe(struct platform_device *pdev) · line 146

Quoted 3 lines

drivers/usb/host/uhci-platform.c +2 -0

 err_rmr:
+     if (uhci->clk)
+             clk_disable_unprepare(uhci->clk);

You don't actually need the test here or below. Both clk_disable and clk_unprepare test for IS_ERR_OR_NULL.

Anyway, this all looks okay. If you want to submit a v4, you can add

Acked-by Alan Stern <[email protected]>

Alan Stern

Quoted 9 lines

drivers/usb/host/uhci-platform.c +1 -0

      usb_put_hcd(hcd);
 
      return ret;

@@ -135,7 +152,10 @@ static int uhci_hcd_platform_probe(struct platform_device *pdev)
 static int uhci_hcd_platform_remove(struct platform_device *pdev)
 {
      struct usb_hcd *hcd = platform_get_drvdata(pdev);
+     struct uhci_hcd *uhci = hcd_to_uhci(hcd);
 

drivers/usb/host/uhci-platform.c static int uhci_hcd_platform_probe(struct platform_device *pdev) · line 160

Quoted 4 lines

drivers/usb/host/uhci-platform.c +2 -0

+     if (uhci->clk)
+             clk_disable_unprepare(uhci->clk);
      usb_remove_hcd(hcd);
      usb_put_hcd(hcd);

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