[v3] usb: uhci: Add clk support to uhci-platform

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Fri, 2018-01-12 at 22:35 -0500, Alan Stern wrote:
> On Sat, 13 Jan 2018, 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 <benh@kernel.crashing.org>
> > ---
> > 
> > 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(-)
> > 
> > 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..0d86ad244922 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);
> > -
> 
> Any particular reason for moving this line up?

Yes, otherwise you can goto the error path without uhci initialized
> 
> >       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;
> >  
> >  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.

Ah ok, it won't hurt tho, but I can do a v4 later or tomorrow.

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

Thanks!

> Acked-by: Alan Stern <stern@rowland.harvard.edu>
> 
> Alan Stern
> 
> >       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);
> >  
> > +     if (uhci->clk)
> > +             clk_disable_unprepare(uhci->clk);
> >       usb_remove_hcd(hcd);
> >       usb_put_hcd(hcd);
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-usb" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
---
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html