Re: [PATCH v2] gpio: dwapb: Add support for a bus clock

From: Andy Shevchenko
Date: Tue Mar 13 2018 - 12:35:39 EST


On Mon, Mar 12, 2018 at 8:30 PM, Phil Edworthy
<phil.edworthy@xxxxxxxxxxx> wrote:
> Enable an optional bus clock provided by DT.

FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

(Assuming it has been tested on clock-less cases)

> Signed-off-by: Phil Edworthy <phil.edworthy@xxxxxxxxxxx>
> ---
> 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@xxxxxxxxxxxx
> */
> #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