linux-kernel - RE: [PATCH v2] gpio: dwapb: Add support for a bus clock

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Date:   Tue, 13 Mar 2018 16:42:35 +0000
From:   Phil Edworthy <phil.edworthy@...esas.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
CC:     Hoan Tran <hotran@....com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Michel Pollet <michel.pollet@...renesas.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2] gpio: dwapb: Add support for a bus clock

Hi Andy,

On 13 March 2018 16:36, Andy Shevchenko wrote:
> On Mon, Mar 12, 2018 at 8:30 PM, Phil Edworthy
> <phil.edworthy@...esas.com> wrote:
> > Enable an optional bus clock provided by DT.
> 
> FWIW,
> Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
Thanks!
 
> (Assuming it has been tested on clock-less cases)
I hacked together a test where the bus clock for the device I have
is always on, and the clock for this driver is not present in the DTB.
Whilst not ideal, it does test the clock-less case.

Thanks
Phil
 
> > Signed-off-by: Phil Edworthy <phil.edworthy@...esas.com>
> > ---
> > v2:
> >  - Fix include order.
> >  - Use a clock name.
> >  - Check errors from clk_prepare_enable()
> >  - Add calls to enable/disable the clock in PM
> > ---
> >  drivers/gpio/gpio-dwapb.c | 20 +++++++++++++++++++-
> >  1 file changed, 19 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
> > index b0704a8..226977f 100644
> > --- a/drivers/gpio/gpio-dwapb.c
> > +++ b/drivers/gpio/gpio-dwapb.c
> > @@ -8,8 +8,9 @@
> >   * All enquiries to support@...ochip.com
> >   */
> >  #include <linux/acpi.h>
> > -#include <linux/gpio/driver.h>
> > +#include <linux/clk.h>
> >  #include <linux/err.h>
> > +#include <linux/gpio/driver.h>
> >  #include <linux/init.h>
> >  #include <linux/interrupt.h>
> >  #include <linux/io.h>
> > @@ -98,6 +99,7 @@ struct dwapb_gpio {
> >         struct irq_domain       *domain;
> >         unsigned int            flags;
> >         struct reset_control    *rst;
> > +       struct clk              *clk;
> >  };
> >
> >  static inline u32 gpio_reg_v2_convert(unsigned int offset) @@ -670,6
> > +672,16 @@ static int dwapb_gpio_probe(struct platform_device *pdev)
> >         if (IS_ERR(gpio->regs))
> >                 return PTR_ERR(gpio->regs);
> >
> > +       /* Optional bus clock */
> > +       gpio->clk = devm_clk_get(&pdev->dev, "bus");
> > +       if (!IS_ERR(gpio->clk)) {
> > +               err = clk_prepare_enable(gpio->clk);
> > +               if (err) {
> > +                       dev_info(&pdev->dev, "Cannot enable clock\n");
> > +                       return err;
> > +               }
> > +       }
> > +
> >         gpio->flags = 0;
> >         if (dev->of_node) {
> >                 const struct of_device_id *of_devid; @@ -712,6 +724,7
> > @@ static int dwapb_gpio_remove(struct platform_device *pdev)
> >         dwapb_gpio_unregister(gpio);
> >         dwapb_irq_teardown(gpio);
> >         reset_control_assert(gpio->rst);
> > +       clk_disable_unprepare(gpio->clk);
> >
> >         return 0;
> >  }
> > @@ -757,6 +770,8 @@ static int dwapb_gpio_suspend(struct device *dev)
> >         }
> >         spin_unlock_irqrestore(&gc->bgpio_lock, flags);
> >
> > +       clk_disable_unprepare(gpio->clk);
> > +
> >         return 0;
> >  }
> >
> > @@ -768,6 +783,9 @@ static int dwapb_gpio_resume(struct device *dev)
> >         unsigned long flags;
> >         int i;
> >
> > +       if (!IS_ERR(gpio->clk))
> > +               clk_prepare_enable(gpio->clk);
> > +
> >         spin_lock_irqsave(&gc->bgpio_lock, flags);
> >         for (i = 0; i < gpio->nr_ports; i++) {
> >                 unsigned int offset;
> > --
> > 2.7.4
> >
> 
> 
> 
> --
> With Best Regards,
> Andy Shevchenko