RE: [PATCH 1/2] gpio: xilinx: Add clock adaptation support

[Srinivas Neeli <sneeli@xxxxxxxxxx>]

Hi,
I agree ,will address comments in V2.

> -----Original Message-----
> From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> Sent: Tuesday, February 18, 2020 9:33 PM
> To: Srinivas Neeli <sneeli@xxxxxxxxxx>
> Cc: Michal Simek <michals@xxxxxxxxxx>; Shubhrajyoti Datta
> <shubhraj@xxxxxxxxxx>; Srinivas Goud <sgoud@xxxxxxxxxx>; Linus Walleij
> <linus.walleij@xxxxxxxxxx>; LKML <linux-kernel@xxxxxxxxxxxxxxx>; arm-soc
> <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>; linux-gpio <linux-
> gpio@xxxxxxxxxxxxxxx>; git <git@xxxxxxxxxx>
> Subject: Re: [PATCH 1/2] gpio: xilinx: Add clock adaptation support
> 
> pon., 17 lut 2020 o 11:57 Srinivas Neeli <srinivas.neeli@xxxxxxxxxx> napisał(a):
> >
> > Add support of clock adaptation for AXI GPIO driver.
> >
> > Signed-off-by: Srinivas Neeli <srinivas.neeli@xxxxxxxxxx>
> > ---
> >  drivers/gpio/gpio-xilinx.c | 105
> > ++++++++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 103 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
> > index a9748b5198e6..26753ae58295 100644
> > --- a/drivers/gpio/gpio-xilinx.c
> > +++ b/drivers/gpio/gpio-xilinx.c
> > @@ -14,6 +14,8 @@
> >  #include <linux/io.h>
> >  #include <linux/gpio/driver.h>
> >  #include <linux/slab.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/clk.h>
> >
> >  /* Register Offset Definitions */
> >  #define XGPIO_DATA_OFFSET   (0x0)      /* Data register  */
> > @@ -38,6 +40,7 @@
> >   * @gpio_state: GPIO state shadow register
> >   * @gpio_dir: GPIO direction shadow register
> >   * @gpio_lock: Lock used for synchronization
> > + * @clk: clock resource for this driver
> >   */
> >  struct xgpio_instance {
> >         struct gpio_chip gc;
> > @@ -45,7 +48,8 @@ struct xgpio_instance {
> >         unsigned int gpio_width[2];
> >         u32 gpio_state[2];
> >         u32 gpio_dir[2];
> > -       spinlock_t gpio_lock[2];
> > +       spinlock_t gpio_lock[2];        /* For serializing operations */
> > +       struct clk *clk;
> >  };
> >
> >  static inline int xgpio_index(struct xgpio_instance *chip, int gpio)
> > @@ -255,6 +259,70 @@ static void xgpio_save_regs(struct xgpio_instance
> *chip)
> >                        chip->gpio_dir[1]);  }
> >
> > +static int xgpio_request(struct gpio_chip *chip, unsigned int offset)
> > +{
> > +       int ret = pm_runtime_get_sync(chip->parent);
> > +
> > +       /*
> > +        * If the device is already active pm_runtime_get() will return 1 on
> > +        * success, but gpio_request still needs to return 0.
> > +        */
> > +       return ret < 0 ? ret : 0;
> > +}
> > +
> > +static void xgpio_free(struct gpio_chip *chip, unsigned int offset) {
> > +       pm_runtime_put(chip->parent);
> > +}
> > +
> > +static int __maybe_unused xgpio_suspend(struct device *dev) {
> > +       struct platform_device *pdev = to_platform_device(dev);
> > +       int irq = platform_get_irq(pdev, 0);
> > +       struct irq_data *data = irq_get_irq_data(irq);
> > +
> > +       if (!irqd_is_wakeup_set(data))
> > +               return pm_runtime_force_suspend(dev);
> > +
> > +       return 0;
> > +}
> > +
> > +static int __maybe_unused xgpio_resume(struct device *dev) {
> > +       struct platform_device *pdev = to_platform_device(dev);
> > +       int irq = platform_get_irq(pdev, 0);
> > +       struct irq_data *data = irq_get_irq_data(irq);
> > +
> > +       if (!irqd_is_wakeup_set(data))
> > +               return pm_runtime_force_resume(dev);
> > +
> > +       return 0;
> > +}
> > +
> > +static int __maybe_unused xgpio_runtime_suspend(struct device *dev) {
> > +       struct platform_device *pdev = to_platform_device(dev);
> > +       struct xgpio_instance *gpio = platform_get_drvdata(pdev);
> > +
> > +       clk_disable(gpio->clk);
> > +
> > +       return 0;
> > +}
> > +
> > +static int __maybe_unused xgpio_runtime_resume(struct device *dev) {
> > +       struct platform_device *pdev = to_platform_device(dev);
> > +       struct xgpio_instance *gpio = platform_get_drvdata(pdev);
> > +
> > +       return clk_enable(gpio->clk);
> > +}
> > +
> > +static const struct dev_pm_ops xgpio_dev_pm_ops = {
> > +       SET_SYSTEM_SLEEP_PM_OPS(xgpio_suspend, xgpio_resume)
> > +       SET_RUNTIME_PM_OPS(xgpio_runtime_suspend,
> > +                          xgpio_runtime_resume, NULL) };
> > +
> >  /**
> >   * xgpio_of_probe - Probe method for the GPIO device.
> >   * @pdev: pointer to the platform device @@ -323,6 +391,8 @@ static
> > int xgpio_probe(struct platform_device *pdev)
> >         chip->gc.direction_output = xgpio_dir_out;
> >         chip->gc.get = xgpio_get;
> >         chip->gc.set = xgpio_set;
> > +       chip->gc.request = xgpio_request;
> > +       chip->gc.free = xgpio_free;
> >         chip->gc.set_multiple = xgpio_set_multiple;
> >
> >         chip->gc.label = dev_name(&pdev->dev); @@ -333,15 +403,45 @@
> > static int xgpio_probe(struct platform_device *pdev)
> >                 return PTR_ERR(chip->regs);
> >         }
> >
> > +       chip->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
> > +       if (IS_ERR(chip->clk)) {
> > +               if (PTR_ERR(chip->clk) != -ENOENT) {
> > +                       if (PTR_ERR(chip->clk) != -EPROBE_DEFER)
> > +                               dev_err(&pdev->dev, "Input clock not found\n");
> > +                       return PTR_ERR(chip->clk);
> > +               }
> > +               /*
> > +                * Clock framework support is optional, continue on
> > +                * anyways if we don't find a matching clock.
> > +                */
> 
> Why not use devm_clk_get_optional() then?
> 
> > +               chip->clk = NULL;
> > +       }
> > +       status = clk_prepare_enable(chip->clk);
> > +       if (status < 0) {
> > +               dev_err(&pdev->dev, "Failed to prepare clk\n");
> > +               return status;
> > +       }
> > +       pm_runtime_enable(&pdev->dev);
> > +       status = pm_runtime_get_sync(&pdev->dev);
> > +       if (status < 0)
> > +               goto err_unprepare_clk;
> > +
> >         xgpio_save_regs(chip);
> >
> >         status = devm_gpiochip_add_data(&pdev->dev, &chip->gc, chip);
> >         if (status) {
> >                 dev_err(&pdev->dev, "failed to add GPIO chip\n");
> > -               return status;
> > +               goto err_pm_put;
> >         }
> >
> > +       pm_runtime_put(&pdev->dev);
> >         return 0;
> > +err_pm_put:
> > +       pm_runtime_put(&pdev->dev);
> > +err_unprepare_clk:
> > +       pm_runtime_disable(&pdev->dev);
> > +       clk_unprepare(chip->clk);
> > +       return status;
> >  }
> >
> >  static const struct of_device_id xgpio_of_match[] = { @@ -356,6
> > +456,7 @@ static struct platform_driver xgpio_plat_driver = {
> >         .driver         = {
> >                         .name = "gpio-xilinx",
> >                         .of_match_table = xgpio_of_match,
> > +                       .pm = &xgpio_dev_pm_ops,
> >         },
> >  };
> >
> > --
> > 2.7.4
> >