Hello!

On 1/15/2018 1:59 AM, Benjamin Herrenschmidt wrote:

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]>
Acked-by: Alan Stern <[email protected]>
---

v4. Remove unnecessary NULL checks

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 | 20 ++++++++++++++++++--
  2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/uhci-hcd.h b/drivers/usb/host/uhci-hcd.h
index f1cc47292a59..7f9f33c8c232 100644
--- a/drivers/usb/host/uhci-hcd.h
+++ b/drivers/usb/host/uhci-hcd.h
@@ -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);
diff --git a/drivers/usb/host/uhci-platform.c b/drivers/usb/host/uhci-platform.c
index 6cb16d4b2257..55c2d99bf7ec 100644
--- a/drivers/usb/host/uhci-platform.c
+++ b/drivers/usb/host/uhci-platform.c
@@ -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);
- uhci = hcd_to_uhci(hcd);
-
        uhci->regs = hcd->regs;
/* Grab some things from the device-tree */
@@ -119,6 +119,19 @@ 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;
+       }
+       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 +140,7 @@ static int uhci_hcd_platform_probe(struct platform_device 
*pdev)
        return 0;
err_rmr:
+       clk_disable_unprepare(uhci->clk);

Really? You haven't enabled the clock before either *goto* above, why disable it here?

        usb_put_hcd(hcd);
return ret;
[...]

MBR, Sergei
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