Re: [PATCH V2 4/8] gpio: vf610: add optional clock support

[Stefan Agner <stefan@agner.ch>]

On 23.10.2018 13:49, A.s. Dong wrote:
> Some SoCs need the gpio clock to be enabled before accessing
> HW registers. This patch add the optional clock handling.
> 
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Stefan Agner <stefan@agner.ch>
> Cc: Shawn Guo <shawnguo@kernel.org>
> Cc: linux-gpio@vger.kernel.org
> Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
> ---
> v1->v2:
>  * new patch
> ---
>  drivers/gpio/gpio-vf610.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/drivers/gpio/gpio-vf610.c b/drivers/gpio/gpio-vf610.c
> index d4ad6d0..cbc4f44 100644
> --- a/drivers/gpio/gpio-vf610.c
> +++ b/drivers/gpio/gpio-vf610.c
> @@ -16,6 +16,7 @@
>   */
>  
>  #include <linux/bitops.h>
> +#include <linux/clk.h>
>  #include <linux/err.h>
>  #include <linux/gpio.h>
>  #include <linux/init.h>
> @@ -256,6 +257,7 @@ static int vf610_gpio_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct device_node *np = dev->of_node;
> +	struct clk *clk_gpio, *clk_port;
>  	struct vf610_gpio_port *port;
>  	struct resource *iores;
>  	struct gpio_chip *gc;
> @@ -280,6 +282,24 @@ static int vf610_gpio_probe(struct platform_device *pdev)
>  	if (port->irq < 0)
>  		return port->irq;
>  
> +	clk_gpio = devm_clk_get(&pdev->dev, "gpio");
> +	clk_port = devm_clk_get(&pdev->dev, "port");

Are you sure that those are two independent clocks? On i.MX 7 usually
there was a single clock gate controlling multiple clocks at once (which
should be modeled as a single clock gate in the clock tree).

--
Stefan 

> +	if ((PTR_ERR(clk_gpio) == -EPROBE_DEFER) ||
> +	    (PTR_ERR(clk_port) == -EPROBE_DEFER)) {
> +		return -EPROBE_DEFER;
> +	} else if (!IS_ERR_OR_NULL(clk_gpio) &&
> +		   !IS_ERR_OR_NULL(clk_port)) {
> +		ret = clk_prepare_enable(clk_gpio);
> +		if (ret)
> +			return ret;
> +
> +		ret = clk_prepare_enable(clk_port);
> +		if (ret) {
> +			clk_disable_unprepare(clk_gpio);
> +			return ret;
> +		}
> +	}
> +
>  	gc = &port->gc;
>  	gc->of_node = np;
>  	gc->parent = dev;