Re: [PATCH 1/1] Blackfin I2C Driver: Functional power management support

[Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>]

On Mon, Jul 28, 2008 at 06:07:28PM +0800, Bryan Wu wrote:
> On Mon, Jul 28, 2008 at 5:23 PM, Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org> wrote:
> > On Sun, Jul 27, 2008 at 02:41:54PM +0800, Bryan Wu wrote:
> >> From: Michael Hennerich <michael.hennerich-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>
> >>
> >> PM_SUSPEND_MEM: Blackfin does not maintain register state through
> >> Hibernate. Save and restore peripheral base initialization during
> >> PM transitions.
> >>
> >> Signed-off-by: Michael Hennerich <michael.hennerich-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>
> >> Signed-off-by: Bryan Wu <cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> >> ---
> >>  drivers/i2c/busses/i2c-bfin-twi.c |   35 ++++++++++++++++++++++++-----------
> >>  1 files changed, 24 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c
> >> index 48d084b..3c855ff 100644
> >> --- a/drivers/i2c/busses/i2c-bfin-twi.c
> >> +++ b/drivers/i2c/busses/i2c-bfin-twi.c
> >> @@ -49,6 +49,8 @@ struct bfin_twi_iface {
> >>       struct i2c_msg          *pmsg;
> >>       int                     msg_num;
> >>       int                     cur_msg;
> >> +     u16                     saved_clkdiv;
> >> +     u16                     saved_control;
> >>       void __iomem            *regs_base;
> >>  };
> >>
> >> @@ -565,32 +567,43 @@ static u32 bfin_twi_functionality(struct i2c_adapter *adap)
> >>              I2C_FUNC_I2C;
> >>  }
> >>
> >> -
> >>  static struct i2c_algorithm bfin_twi_algorithm = {
> >>       .master_xfer   = bfin_twi_master_xfer,
> >>       .smbus_xfer    = bfin_twi_smbus_xfer,
> >>       .functionality = bfin_twi_functionality,
> >>  };
> >>
> >> -
> >> -static int i2c_bfin_twi_suspend(struct platform_device *dev, pm_message_t state)
> >> +static int i2c_bfin_twi_suspend(struct platform_device *pdev, pm_message_t state)
> >>  {
> >> -     struct bfin_twi_iface *iface = platform_get_drvdata(dev);
> >> +     struct bfin_twi_iface *iface = platform_get_drvdata(pdev);
> >> +
> >> +     iface->saved_clkdiv = read_CLKDIV(iface);
> >> +     iface->saved_control = read_CONTROL(iface);
> >> +
> >> +     free_irq(iface->irq, iface);
> >>
> >>       /* Disable TWI */
> >> -     write_CONTROL(iface, read_CONTROL(iface) & ~TWI_ENA);
> >> -     SSYNC();
> >> +     write_CONTROL(iface, iface->saved_control & ~TWI_ENA);
> >
> > I assume removing the SSYNC() call is valid?
> >
> 
> Yes, I think it is OK for that. We tested on our platform.
> Actually, keeping the SSYNC() is not a big deal for this driver.
> How do you think Michael?
> 
> >>       return 0;
> >>  }
> >>
> >> -static int i2c_bfin_twi_resume(struct platform_device *dev)
> >> +static int i2c_bfin_twi_resume(struct platform_device *pdev)
> >>  {
> >> -     struct bfin_twi_iface *iface = platform_get_drvdata(dev);
> >> +     struct bfin_twi_iface *iface = platform_get_drvdata(pdev);
> >>
> >> -     /* Enable TWI */
> >> -     write_CONTROL(iface, read_CONTROL(iface) | TWI_ENA);
> >> -     SSYNC();
> >> +     int rc = request_irq(iface->irq, bfin_twi_interrupt_entry,
> >> +             IRQF_DISABLED, pdev->name, iface);
> >> +     if (rc) {
> >> +             dev_err(&pdev->dev, "Can't get IRQ %d !\n", iface->irq);
> >> +             return -ENODEV;
> >> +     }
> >> +
> >> +     /* Resume TWI interface clock as specified */
> >> +     write_CLKDIV(iface, iface->saved_clkdiv);
> >> +
> >> +     /* Resume TWI */
> >> +     write_CONTROL(iface, iface->saved_control);
> >>
> >>       return 0;
> >>  }
> >> --
> >> 1.5.6
> >
> > if removing the SSYNC() call is ok, then I'll queue this into
> > my tree which I will be requesting a pull asap.

ok, this is in my queue, unless anyone objects then it'll be pushed
out later today.

-- 
Ben

Q:      What's a light-year?
A:      One-third less calories than a regular year.


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